CN112023603B - Ship tail gas washing and purifying system and method suitable for swing/start-stop complex working conditions - Google Patents

Abstract

The invention relates to a ship tail gas washing and purifying system and a method suitable for swinging/starting and stopping complex working conditions. The invention aims at a plurality of absorbent SO under complex conditions such as different sea areas, different emission requirements, different meteorological conditions, different ship engines/running conditions and the like ₂ The difficult problem of high-efficient stable low-cost desorption provides a ship tail gas washing and purifying system and method suitable for swinging/starting and stopping complex working conditions, and the device and method for realizing various pollutants of the ship tail gas, especially SO (SO) through the rapid temperature adjustment of a pre-washing turbulence temperature adjustment section, the reinforcement of gas-liquid mixing by a liquid redistribution component, the flexible collaborative adjustment and control of multiple factors and the like ₂ The method solves the problems of high-efficiency stable desulfurization under the working conditions of tower body swing, quick start and stop of the ship, seawater change and the like, and provides support for high-efficiency stable safe and reliable removal of the tail gas pollutants of the ship.

Description

Ship exhaust gas scrubbing and purification system and method suitable for complex swing/start-stop working conditions

Technical field

The invention belongs to the technical field of air pollutant control, and specifically relates to a ship exhaust gas scrubbing and purification system and method suitable for complex swing/start-stop working conditions.

Background technique

In recent years, my country has made significant progress in reducing air pollutant emissions, and the problem of ship exhaust pollutant emissions has become increasingly prominent. China's ships emit a huge amount of SO ₂ , and most ship pollutants are discharged in offshore areas, which has become an important cause of air pollution in coastal areas and ports.

Since 1997, the International Maritime Organization (IMO) has gradually set up four major emission control areas (ECA) around the world: the Baltic Sea, the North Sea, North America, and the U.S. Caribbean Sea, all of which have put forward new requirements for SOx emission control. Currently, the International Maritime Organization (IMO) has increasingly strict limits on ship exhaust pollutant emissions. At the same time, governments in some countries and regions in North America, Europe and Asia have also introduced ship pollution emission control policies and standards. At the 58th meeting of the Marine Environment Protection Committee (MEPC), the amendment to Annex VI of the MARPOL73/78 Convention on reducing sulfur oxide emissions from ships was adopted. The tail gas sulfur oxide emissions put forward new requirements for ship exhaust control on a global scale. All have put forward strict requirements. The Ministry of Transport of China established a ship air pollutant emission control area in 2015. In 2018, the control area plan was upgraded and adjusted to include areas within 12 nautical miles of my country's coast and inland navigation areas such as the Yangtze River. The scope of the control area was It has put forward detailed control requirements for ship SOx, NOx and other pollutant emissions within the country; at the same time, my country began to implement the "Ship Engine Exhaust Pollutant Emission Limits" issued by the Ministry of Environmental Protection in conjunction with the General Administration of Quality Supervision, Inspection and Quarantine on July 1, 2018. and Measurement Methods (China Phase I and Phase II)" Phase I standards. At present, the main methods to achieve sulfur emission targets are: low-sulfur oil or alternative fuels, and installing ship exhaust gas scrubbing devices. The cost of using low-sulfur oil or alternative fuels is relatively high. Installing ship flue gas scrubbers is one of the important measures to control ship SO ₂ emissions. However, ship engine room space is limited and requires high reliability, safety and applicability of absorbents. It also faces problems such as swinging under conditions such as storms and waves. For different ships/aircraft models, different absorbents, and different sea area working conditions, , how to achieve efficient, stable and low-cost desulfurization is still an urgent problem to be solved.

Contents of the invention

This invention aims at the problem of efficient, stable and low-cost removal of SO ₂ from multiple absorbents under complex conditions such as different sea areas, different emission requirements, different meteorological conditions, different ship engines/operating conditions, etc., and provides a method suitable for complex swing/start-stop operations. The ship exhaust gas scrubbing and purification system and method under working conditions, through the rapid temperature regulation of the pre-washing turbulent temperature regulation section, the liquid redistribution component to strengthen the gas-liquid mixing, and the flexible coordinated regulation of multiple factors, realize the purification of various pollutants in the ship exhaust gas, especially It is a low-cost and efficient removal of SO ₂ , which solves the problem of efficient and stable desulfurization under working conditions such as tower swing, rapid start and stop of ships, changes in sea water, etc., and provides support for the efficient, stable, safe and reliable removal of ship exhaust pollutants.

A ship exhaust gas scrubbing and purification system suitable for complex swing/start-stop working conditions. The system includes a connected exhaust gas pre-washing turbulent temperature regulation section, a compact high-efficiency enhanced mass transfer scrubbing tower and a multi-factor flexible control system;

In view of the frequent fluctuations of ship engines/operating conditions and the large fluctuation range of exhaust gas flow (10% to 100%), it is difficult to flexibly control the velocity field, concentration field, temperature field, etc. of the exhaust gas pre-washing turbulent temperature regulation section with the load. According to different voyages It is required that the tail gas pre-washing turbulent temperature control section includes more than one tail gas pre-wash turbulent temperature control section branch to achieve rapid cooling of high-temperature tail gas, facilitate flexible control of the tail gas flow field entering the tower, and achieve rapid cooling of high-temperature tail gas; the tail gas pre-washing The branch of the turbulent temperature regulation section includes a pre-washing and cooling section, a turbulence-enhancing mixing section, and a cooling rectification section arranged in sequence from top to bottom. The inlet end of the pre-washing and cooling layer is provided with a first cooling spray pre-washing layer to enhance turbulence. The upper end of the mixing section is provided with a second cooling spray pre-washing layer;

The exhaust gas pre-washing turbulent temperature regulation section is connected with the exhaust gas channel, and anti-swing guide vanes are provided in the exhaust gas channel;

The compact and high-efficiency enhanced mass transfer scrubber includes a liquid collection area arranged in sequence from bottom to top, a multi-zone enhanced mass transfer layer suitable for swinging, a liquid phase reaggregation and redistribution ring suitable for swinging, and a liquid-gas ratio suitable for swinging. Control layer, eddy current agglomeration device and mist eliminator. The multi-zone enhanced mass transfer layer suitable for swing is composed of multiple small hole corrugated plate liquid holding areas. The liquid-gas ratio control layer suitable for swing includes a variable frequency circulation pump, spray pipe, an anti-sway nozzle and a pipeline switching device, the anti-swing nozzle is arranged on the spray pipe, and the variable frequency circulation pump is connected to the spray pipe through the pipeline switching device;

The multi-factor flexible control system includes a washing liquid circulation tank, a detergent addition pipeline, a seawater pipeline, a monitoring device and a detergent switching device. The washing liquid circulation tank is connected to the detergent switching device and the monitoring device respectively. The washing liquid circulation tank The liquid circulation tank is connected to the spray pipe through a variable frequency circulation pump and a pipeline switching device. The detergent switching device is connected to the detergent adding pipeline and the seawater pipeline respectively.

Preferably, the cooling spray layer is arranged at the entrance end of the pre-wash cooling section and the upper end of the turbulence-enhanced mixing section, and is connected with an electric valve to realize the regulation and distribution of the cooling pre-wash liquid;

The tail gas pre-washing turbulent temperature regulation section and the compact high-efficiency enhanced mass transfer scrubber are arranged in a compact "U-shaped" or "W-shaped" structure; the liquid collection area is connected to the washing liquid circulation tank through a washing liquid collection pipe. .

Preferably, the first cooling spray layer includes a multi-section Venturi type spray main pipe, cooling spray branch pipes with the same pipe diameter and staggered distribution, a first cooling nozzle and a second cooling nozzle, the first cooling nozzle and The cooling spray branch pipes with the same pipe diameter are staggered and correspond one to one. At the same time, in order to further increase the heat exchange effect, a second cooling nozzle is provided at the starting end of the Venturi type spray main pipe, and the first cooling nozzle is The cooling nozzle and the second cooling nozzle are one-way 90° or 120° solid spiral cone nozzles; the tail gas flow rate at the entrance end of the pre-washing cooling section is relatively gentle, and the spray main pipe adopts a multi-stage Venturi type to ensure that the cooling spray liquid is kept at a relatively low temperature. A large flow rate enters the entrance end of the pre-washing and cooling section, which enhances the mixing and heat exchange effect of the exhaust gas. The solid spiral cone nozzle ensures that the atomized droplets are sprayed in a spiral shape and meet the high-temperature exhaust gas in the same flow direction to form a spiral vortex, which is helpful to Enhance heat exchange.

Preferably, the second cooling spray layer includes a main spray pipe with the same diameter, a cooling spray branch pipe with a staggered distribution of the same diameter, and a third cooling nozzle. The third cooling nozzle is interlaced with the cooling spray pipe of the same diameter. The shower pipes correspond one to one; the third cooling nozzle is a bidirectional 90° or 120° solid cone nozzle; the tail gas flow rate in the turbulence-enhanced mixing section is larger, which strengthens the heat exchange effect of mixing the tail gas and the cooling washing liquid, and promotes the temperature of the tail gas to further increase Rapid reduction; the solid cone nozzle atomizes droplets in the same direction as the exhaust gas flow, and the bidirectional nozzle strengthens the coverage area with high-temperature exhaust gas, further enhancing the cooling of high-temperature exhaust gas.

Preferably, the anti-swing guide vane is driven by an electric mechanism to form an angle between the guide vane and the exhaust gas passage in the horizontal direction of 0° to 5°, while changing the cross-sectional area of the exhaust passage; when the ship engine load is less than 30%, the When the exhaust gas flow rate entering the tower is low at low load, the horizontal angle between the guide vanes and the exhaust channel is 10° to 15°, and the cross-sectional area of the exhaust channel is reduced by 20% to 30%; when the ship swings more than 10°, in order to slow down the ship swing The phenomenon of uneven distribution of exhaust gas velocity field, concentration field, temperature field, etc. when the exhaust gas enters the compact high-efficiency mass transfer scrubber. The anti-swing guide vane is driven by an electric mechanism and the angle between the guide vane and the horizontal direction of the exhaust gas channel is 0°. ~5°.

In order to prevent the downward washing liquid in the compact high-efficiency mass transfer scrubber from entering the connecting exhaust gas channel, preferably, a rain shield is provided at the connection between the exhaust gas channel and the compact high-efficiency enhanced mass transfer scrubber, and the rain shield is connected to the compact exhaust gas channel. A high-efficiency mass transfer scrubbing tower with an angle of 80° in the vertical downward direction and a length of 200~500mm.

After the ship exhaust gas passes through the liquid-holding area of the small-hole corrugated plate, it contacts the washing liquid to strengthen the turbulent mixing of gas and liquid, and forms a liquid-holding layer of a certain height, which further strengthens the gas-liquid absorption and mass transfer contact time and improves the pollutant removal efficiency; as a preferred option, The small-hole corrugated plate liquid-holding area includes a liquid-holding plate, and the liquid-holding plate is provided with openings. The hole shape of the openings is a circular hole or a "herringbone"-shaped hole; the diameter of the circular hole is 15 mm to 25 mm. The opening rate is 25% ~ 35%; the side length of the "herringbone" hole is 5mm ~ 8mm, and the opening rate is 25% ~ 30%; in order to reduce the uneven distribution of liquid holding layer height in the multi-zone enhanced mass transfer layer caused by ship swings , the height of the liquid-holding plate in the liquid-holding area of the small hole corrugated plate is preferably 200mm~300mm.

The liquid phase regrouping and redistribution ring is arranged below the spray layer, connected to the wall weld of the compact high-efficiency mass transfer scrubbing tower at a certain angle, and has holes to redisperse the descending liquid droplets into small droplets. Liquid phase reaggregation and redistribution - increase the gas flow rate, increase the spray coverage, increase the density of droplets, further improve the sulfur dioxide absorption efficiency, and reduce the escape of exhaust gas against the wall when the ship swings and the removal of pollutants caused by uneven distribution of the washing liquid. Efficiency instability phenomenon; as a preference, the liquid phase reaggregation and redistribution ring is connected at a certain angle with the weld seam on the inner wall of the enhanced mass transfer scrubber shell, and the liquid phase reaggregation and redistribution ring is arranged 800mm~ below the spray pipe At 1000mm; the area ratio between the liquid phase reaggregation and redistribution ring and the compact high-efficiency mass transfer scrubber is 5% to 10%, and the angle between the liquid phase reaggregation and redistribution ring and the inner wall of the enhanced mass transfer scrubber shell is 45° to 60°. The aperture of the distribution ring is 20mm~30mm, and the opening rate is 30%~45%.

In order to alleviate the problem of unstable desulfurization efficiency caused by large swings of ships in sea conditions such as storms and waves, multi-layer liquid-to-gas ratio control areas are set up to form a multi-dimensional and multi-scale ship exhaust gas capture network; the liquid-to-gas ratio control areas and zones are The spray main pipe is connected with an electric valve, and the spray main pipe is connected to a washing liquid frequency conversion circulation pump to achieve flexible regulation of the liquid-gas ratio in the compact and high-efficiency mass transfer scrubber under different navigation areas and loads.

At the same time, in order to ensure the uniformity of the washing liquid and reduce the possibility of ship exhaust gas escaping, it is preferred that the number of liquid-gas ratio control layers is 3 to 5, wherein a single liquid-gas ratio control layer includes multiple liquid-gas ratio control layers Sub-area, the sub-area nozzles adopt anti-swing and ultra-fine particle size atomization nozzles to maximize the washing liquid spray coverage.

In order to reduce the angle between the atomized washing liquid droplets and the upward ship exhaust gas caused by the ship swinging and other navigation environment, and slow down the decrease in spray coverage caused by the ship swinging and other navigation environment, it is further preferred that the spray angle deviation of the nozzle in the sub-region is preferably ± 5% to 10%, the median diameter of the nozzle atomized droplet volume (Dv0.5) should be less than 500 μm.

Preferably, the vortex agglomeration device includes an even number of alternating rows of rounded "Z" and reverse "Z" spoilers. The spoiler angle is 30°, with the rounded "Z" and reverse "Z" spoilers. The end of the spoiler is regularly arranged with saw teeth of the same size. The shape of the saw teeth is triangular or rectangular. The total length of the spoiler is 1000~1500mm. After purification, the exhaust gas carrying droplets such as dust and carbon black particles flows through the spoiler. During flow, a large number of vortices of different sizes can be generated in different directions in the compact high-efficiency mass transfer scrubber, effectively promoting the collision and agglomeration between droplets and particles, promoting the growth of droplets carried in ship exhaust, collision and separation, and strengthening Removal of carbon black, PAHs and other pollutants in ship exhaust gas.

As a preferred option, the compact enhanced mass transfer scrubber has a multi-zone enhanced mass transfer layer, a liquid phase reaggregation and redistribution ring, a liquid-gas ratio control area and a vortex agglomeration and mist-removing area to form a stable flow design, which can reduce the liquid-gas ratio. The same desulfurization efficiency can be achieved by more than 10%, which is beneficial to the economical operation of the desulfurization system.

A multi-factor flexible control system is used to monitor the pH, temperature, components of the washing liquid in the circulating tank and other factors that affect the sulfur dioxide efficiency through a monitoring device, and the detergent switching device is used to flexibly control the pH, temperature, and liquid phase components of the washing liquid, further Through the pipeline switching device, the liquid-gas ratio in the compact high-efficiency mass transfer scrubber can be flexibly regulated, and the liquid-gas ratio can be comprehensively adjusted, as well as the pH, temperature and concentration of the scrubbing liquid to achieve efficient, stable and low-cost SO ₂ removal. , while improving the adaptability, safety and reliability of using multiple absorbents in a single scrubber; as a preference, when seawater is used as the detergent, the pH value of the detergent solution should be controlled at 7.5~8.3, and the total alkalinity should be 2.0~ 3.0mmol/L, the liquid-to-gas ratio of the washing liquid should not be less than 10L/Nm ³ , and the temperature should be controlled at 15 to 30°C; preferably, magnesium hydroxide slurry is used as the detergent, and the pH value of the detergent solution should be controlled at 5.0 to 3.0mmol/L. 6.5, the molar ratio of magnesium to sulfur should not be greater than 1.05, the liquid-to-gas ratio of the washing liquid should be greater than 5L/Nm3, and the temperature should be controlled at 40 to 52°C.

The invention also provides a method for the above system to be used for ship exhaust gas scrubbing and purification in complex anti-sway/start-stop working conditions, which includes the following steps:

The high-temperature exhaust gas enters the pre-washing and cooling section, contacts the spray atomized droplets of the first cooling spray pre-washing layer, and increases its speed through the turbulence-enhanced mixing section, forming a strengthened turbulence zone to strengthen the rapid cooling of the high-temperature exhaust gas. After cooling, the high-temperature exhaust gas enters the cooling section. It is decelerated after the rectification section, and the inertial force of the droplets is increased through turbulence. The temperature of the exhaust gas increases the thermophoretic force of the droplets. The difference in droplet speed increases the probability of collision between droplets, causing small droplets and dust particles to grow and settle. The grown liquid The droplets and dust particles are separated from gas and liquid after passing through the front tail gas channel of the compact high-efficiency mass transfer scrubber, and the separated pollutant droplets enter the liquid collection area through the tail gas channel;

According to different navigation needs, the exhaust gas pre-washing turbulent temperature control section includes more than one exhaust gas pre-wash turbulent temperature control section branch to achieve rapid cooling of high-temperature exhaust gas, facilitate flexible control of the exhaust gas flow field entering the tower, and achieve rapid cooling of high-temperature exhaust gas;

The ship exhaust gas is cooled by the exhaust gas pre-washing turbulent temperature regulation section and then enters the multi-zone enhanced mass transfer layer through the anti-swing guide vanes. The small droplets of the washing liquid contact the ship exhaust gas and tumble under high-speed airflow conditions. The turbulent flow mixes and forms a liquid-holding layer. , which strengthens the gas-liquid absorption and mass transfer contact time, improves the utilization rate of the absorbent, and improves the pollutant removal efficiency; in order to reduce the uneven distribution of the height of the liquid-holding layer in the multi-zone enhanced mass transfer layer caused by ship swings, the small-hole corrugated plate liquid-holding area is Liquid holding plate with a certain height;

After the ship exhaust gas flows up into the liquid phase reaggregation and redistribution ring, the openings in the liquid phase reaggregation and redistribution ring redisperse the downward droplets into small droplets, and the liquid phase reaggregation and redistribution increases the gas flow rate and increases the spray The coverage rate increases the density of droplets, further improves the sulfur dioxide absorption efficiency, and reduces the instability of pollutant removal efficiency caused by the escape of exhaust gas against the wall when the ship swings and uneven distribution of washing liquid;

The ship exhaust gas continues to flow up to the liquid-gas ratio control layer, forming a liquid-gas ratio control area, forming a multi-dimensional and multi-scale ship exhaust gas capture network to achieve exhaust gas purification; at the same time, in order to ensure the uniformity of the washing liquid and reduce the possibility of ship exhaust gas escaping, The single-layer liquid-gas ratio control layer includes multiple liquid-gas ratio control sub-areas, and the sub-area nozzles adopt anti-swing and ultra-fine particle size atomization nozzles to maximize the cleaning liquid spray coverage;

When the purified tail gas carrying droplets such as dust and carbon black particles flows through the vortex agglomeration device, it can generate a large number of vortices of different sizes in different directions in the compact and efficient mass transfer scrubber, effectively promoting the interaction between droplets and particles. Collision and agglomeration promote the collision and separation of liquid droplets carried in the ship's exhaust gas, which strengthens the removal of pollutants in the ship's exhaust gas. The mist droplets are further removed by the demister and then discharged into the atmospheric environment through the tower top chimney;

A multi-factor flexible control system is used to monitor the factors affecting the sulfur dioxide efficiency in the circulation tank through a monitoring device, and the detergent switching device is used to realize flexible control of the pH, temperature, and liquid phase components of the washing liquid, and further the pipeline switching device is used to realize all the requirements. The flexible control of the liquid-gas ratio in a compact high-efficiency mass transfer scrubber, comprehensive liquid-gas ratio, multi-factor control of scrubber pH, temperature and concentration, achieves efficient, stable and low-cost removal of SO ₂ , while improving the use of multiple types of single scrubbers. The adaptability, safety and reliability of the absorbent.

Preferably, the tail gas pre-washing turbulent temperature regulation section and the compact high-efficiency enhanced mass transfer scrubber are arranged in a compact "U-shaped" or "W-shaped" structure; the multi-zone enhanced mass transfer scrubber in the compact The stable flow design consists of the mass layer, the liquid phase reaggregation and redistribution ring, the liquid-gas ratio control area and the vortex aggregation and mist-removing area, which can reduce the liquid-gas ratio by more than 10% to achieve the same desulfurization efficiency, which is beneficial to the economy of the desulfurization system. Sex runs.

Beneficial effects of the present invention:

(1) In view of the frequent fluctuations of ship engines/operating conditions and the large fluctuation range of exhaust gas flow (10% to 100%), it is difficult to flexibly control the velocity field, concentration field, temperature field, etc. of the exhaust gas pre-washing turbulent temperature regulation section with the load. According to different navigation needs, the exhaust gas pre-washing turbulent temperature control section includes more than one exhaust gas pre-wash turbulent temperature control section branch to achieve rapid cooling of high-temperature exhaust gas, facilitate flexible control of the exhaust gas flow field entering the tower, and achieve rapid cooling of high-temperature exhaust gas;

(2) The high-temperature exhaust gas enters the pre-washing cooling section, contacts the spray atomized droplets of the cooling spray pre-washing layer, and increases its speed through the turbulence-enhanced mixing section, forming a strengthened turbulence zone to strengthen the rapid cooling of the high-temperature exhaust gas, and at the same time, the cooled high-temperature exhaust gas After entering the cooling rectification section, it is decelerated, causing the fine droplets and dust particles to grow and settle, thereby realizing the capture and pre-washing of carbon black particles and PAHs in the ship's exhaust gas; after purification, the exhaust gas carrying droplets containing dust, carbon black particles and other droplets flows through When the vortex agglomerates in the defogging zone, a large number of vortices of different sizes are generated in different directions in the compact high-efficiency mass transfer scrubber, which effectively promotes the collision and agglomeration between droplets and particles, and promotes the growth and collision separation of droplets carried in ship exhaust. , strengthen the removal of carbon black, PAHs and other pollutants in ship exhaust gas; after the above treatment, more than 96% of carbon black particles and PAHs in ship exhaust gas can be captured and removed;

(3) Anti-swing guide vanes that can change with the ship load and swing angle are installed in the exhaust channel to prevent the ship from swinging and causing uneven distribution of exhaust gas velocity field, concentration field, temperature field, etc. into the compact high-efficiency mass transfer scrubber; The anti-swing nozzle is used to optimize the spray direction and particle size of atomized droplets to reduce uneven coverage of the washing liquid caused by ship swings; the small hole corrugated plate liquid holding area is used to form multiple washing liquid distribution areas with stable and uniform liquid holding height distribution. Divide the enhanced mass transfer layer into multiple dense-phase enhanced mass transfer areas to reduce the uneven distribution of the height of the liquid-holding layer in the enhanced mass transfer layer caused by ship swings, and slow down the instability of desulfurization efficiency caused by ship swings; use liquid phase repolymerization to regenerate The distribution ring realizes the re-aggregation and redistribution of the liquid phase, reducing the exhaust gas escaping from the wall when the ship swings and the unstable pollutant removal efficiency caused by uneven distribution of the washing liquid;

(4) A multi-zone enhanced mass transfer layer is used to promote the small droplets of the washing liquid to contact the ship exhaust and tumble under high-speed airflow conditions. The turbulent flow mixes and forms a liquid-holding layer with a certain height, which strengthens the gas-liquid absorption and mass transfer contact time and improves the The utilization rate of the absorbent improves the pollutant removal efficiency; after using the liquid phase reaggregation and redistribution ring, the liquid phase reaggregation and redistribution increase the gas flow rate, increase the density of the droplets, and further improve the sulfur dioxide absorption efficiency; set the liquid-gas ratio control layer, forming a multi-dimensional and multi-scale ship exhaust gas capture network. At the same time, in order to ensure the uniformity of the washing liquid and reduce the possibility of ship exhaust gas escaping, the single-layer liquid-gas ratio control layer includes multiple liquid-gas ratio control sub-regions, and sub-region nozzles Use anti-swing and ultra-fine particle size atomization nozzles to maximize washing liquid spray coverage;

(5) A multi-factor flexible control system is used to monitor the pH, temperature, composition and other factors of the washing liquid in the washing liquid circulation tank that affect the sulfur dioxide efficiency through the monitoring device, aiming at different navigation sea areas, emission requirements and ship engine/operating conditions of the ship. Conditions, the desulfurization mode can be switched through the detergent adding device to realize flexible regulation of the pH, temperature, liquid phase components, etc. of the washing liquid, and the liquid in the compact and high-efficiency mass transfer washing tower can be further realized through the washing spray pipeline switching device. Flexible control of the gas ratio, comprehensive liquid-gas ratio, scrubber pH, temperature and concentration and other multi-factor controls achieve efficient, stable and low-cost removal of SO ₂ while improving the adaptability, safety and reliability of using multiple absorbents in a single scrubber. ;

(6) The tail gas pre-washing turbulent temperature regulation section and the compact high-efficiency enhanced mass transfer scrubber are arranged in a compact "U-shaped" or "W-shaped" structure; the multi-zone enhanced mass transfer layer and liquid in the compact enhanced mass transfer scrubber are The phase reintegration and redistribution ring, the liquid-gas ratio control area and the vortex agglomeration and demister area (including the vortex agglomeration device and demister) form a steady flow design, which can reduce the liquid-gas ratio by more than 10% to achieve the same desulfurization efficiency. Conducive to the economical operation of the desulfurization system;

(7) After the ship exhaust gas is processed by a compact and high-efficiency scrubber with rapid temperature regulation in the pre-washing turbulent temperature regulation section, liquid redistribution components to strengthen gas-liquid mixing, and flexible and coordinated regulation of multiple factors, a variety of pollutants can be removed with low cost and high efficiency. , which can effectively solve the problems of efficient, stable and low-cost desulfurization caused by tower swings, changing absorbent liquids, changing sea/seawater conditions, etc. The desulfurization efficiency can reach more than 99%, SO ₂ (ppm)/CO ₂ (%) Exceeds the most stringent requirements of the International Maritime Organization (IMO).

Description of the drawings

Figure 1 is a schematic structural diagram of the ship exhaust gas scrubbing and purification system of the present invention suitable for complex swing/start-stop working conditions;

Figure 2 is a schematic structural diagram of the first cooling pre-washing spray layer arranged at the entrance of the pre-washing and cooling section according to the present invention;

Figure 3 is a schematic structural diagram of the second cooling pre-washing spray layer arranged at the upper end of the turbulence-enhanced mixing section according to the present invention;

Figure 4 is a schematic structural diagram of the liquid-holding area of the corrugated plate with herringbone holes according to the present invention;

Figure 5 is a schematic structural diagram of the eddy current agglomeration device of the present invention;

Figure 6 is a schematic structural diagram of the rounded "Z"-shaped rectangular tooth vortex spoiler of the present invention;

Figure 7 is a schematic structural diagram of a compact high-efficiency mass transfer scrubber with a single tail gas pre-washing turbulent temperature regulation section of the present invention;

Figure 8 is a schematic structural diagram of a compact high-efficiency mass transfer scrubber tower with dual exhaust gas pre-washing turbulent temperature regulation sections according to the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

Example 1

Referring to Figures 1 to 8, a ship exhaust gas scrubbing and purification system suitable for complex swing/start-stop working conditions is shown. The system includes a connected exhaust gas pre-washing turbulent temperature regulating section 1, a compact and efficient enhanced mass transfer scrubbing tower 2 and a multi-factor Flexible control system 3, the compact and efficient enhanced mass transfer scrubber includes an enhanced mass transfer scrubber shell;

The exhaust gas pre-washing turbulent temperature regulation section 1 includes a pre-wash cooling section 11, a turbulence-enhanced mixing section 12, a cooling rectification section 13 and an exhaust gas channel 16 arranged in sequence from top to bottom. The inlet end of the pre-wash cooling section 11 A first cooling spray pre-washing layer 141 is provided, a second cooling spray pre-washing layer 142 is provided at the upper end of the turbulence-enhanced mixing section 12, and an anti-swing guide vane 15 is provided in the exhaust passage 16;

The compact high-efficiency mass transfer scrubber tower includes a liquid collection area 26, a multi-zone enhanced mass transfer layer 21, a liquid phase reaggregation and redistribution ring 22, a liquid-gas ratio control area 23, and a vortex agglomeration device sequentially arranged from bottom to top. 24 and demister 25 (the vortex agglomeration device 24 and the demister 25 form a vortex agglomeration demister layer). The multi-zone enhanced mass transfer layer 21 is composed of a plurality of small hole corrugated plate liquid holding areas 211. The liquid-to-gas ratio The control layer 23 includes a variable frequency circulation pump 231, a spray pipe 232, a pipeline switching device 233 and an anti-swing nozzle 234. Corresponding liquid phase regrouping and redistribution rings 22 are provided below the spray pipe 232;

The multi-factor flexible control system includes a washing liquid collection pipe 31, a washing liquid circulation tank 32, a detergent switching device 33 and a monitoring device 34. The washing liquid circulation tank 32 is connected to the detergent switching device 33 and the monitoring device 34. The detergent switching device 33 is connected to the detergent adding pipe 331 and the seawater pipe 332 respectively. The washing liquid circulation tank 32 is connected to the spray pipe 232 through the frequency conversion circulation pump 231 and the pipeline switching device 233. The spray pipe 232 is connected to the anti-static The swing nozzle 234 is connected, and the liquid collection area 26 is connected with the washing liquid circulation tank 32 through the washing liquid collection pipe 31 .

The first cooling spray pre-washing layer 141 is connected to the first electric valve 171, and the second cooling spray pre-washing layer 142 is connected to the second electric valve 172; the electric valve is connected to realize the regulation and distribution of the cooling pre-washing liquid. .

The tail gas pre-washing turbulent flow temperature regulating section and the compact high-efficiency enhanced mass transfer scrubber are in the form of a compact "U-shaped" (compact high-efficiency mass transfer scrubber with a single tail gas pre-washing turbulent flow temperature-regulating section) or "W-shaped" ( Compact high-efficiency mass transfer scrubber with dual tail gas pre-wash turbulent temperature control sections) structural arrangement; multi-zone enhanced mass transfer layer 21 in the tower, liquid phase reaggregation and redistribution ring 22, liquid-gas ratio control layer 23, vortex flow The agglomeration device 24 and the mist eliminator 25 form a steady flow design, which can reduce the liquid-gas ratio by more than 10% to achieve the same desulfurization efficiency, which is beneficial to the economical operation of the desulfurization system.

The multi-factor flexible control system monitors factors such as pH, temperature, and composition of the washing liquid in the washing liquid circulation tank 32 that affect the sulfur dioxide efficiency through the monitoring device 34 . When the ship sails to the four major emission control areas (ECA) of the Baltic Sea, the North Sea, North America, and the U.S. Caribbean Sea, the multi-factor control system switches the absorbent and adds magnesium hydroxide slurry as a washing additive through the detergent adding pipe 331 . When the ship sails outside the four major emission control areas of the Baltic Sea, the North Sea, North America, and the U.S. Caribbean Sea or burns low-sulfur oil, the multi-factor control device switches absorbent control and adds seawater as a wash through the seawater pipeline 332. agent, the pH value of the detergent solution is controlled to be 7.5-8.3, the total alkalinity is 2.0-3.0mmol/L, the temperature should be controlled at 15-30°C, and the liquid-to-gas ratio of the washing liquid is 12L/Nm ³ , which increases the value by more than one tower. Absorbent adaptability.

The first cooling spray layer 141 at the entrance end of the pre-washing cooling section 11 is composed of a multi-section Venturi spray main pipe 1411, cooling spray branch pipes 1412 with the same pipe diameter and staggered distribution, and first cooling nozzles 1413. The cooling nozzles 1413 correspond to the cooling spray branch pipes 1412. At the same time, in order to further increase the heat exchange effect, a second cooling nozzle 1414 is added to the starting end of the Venturi spray main pipe 1411; The tail gas flow rate at the entrance end of the pre-washing and cooling section 11 is relatively gentle. The spray main pipe 1411 adopts a multi-stage Venturi type to ensure that the cooling spray liquid enters the entrance end of the pre-washing and cooling section 11 at a larger flow rate, thereby strengthening the mixing and exchange of the tail gas. Thermal effect: The cooling nozzle 1413 is preferably a one-way 90° solid spiral cone nozzle. The atomized droplets are sprayed in a spiral shape and meet the high-temperature exhaust gas in the same flow direction to form a spiral vortex, which helps to enhance heat transfer.

The second cooling spray layer 142 at the entrance of the turbulence-enhanced mixing section 12 is composed of a main spray pipe 1421 of the same diameter, a staggered cooling spray branch pipe 1422 of the same diameter, and a third cooling nozzle 1423 . The cooling nozzle 1423 corresponds to the cooling spray branch pipe 1422 one-to-one; the turbulence-enhanced mixing section 12 has a larger tail gas flow rate, which strengthens the heat exchange effect of mixing the tail gas and the cooling washing liquid, and promotes a further rapid reduction in tail gas temperature; The cooling nozzle 1423 is preferably a bidirectional 90° solid cone nozzle. The spray direction of the atomized droplets is consistent with the flow direction of the exhaust gas. The bidirectional nozzle 1423 enhances the coverage area of the high-temperature exhaust gas and further enhances the cooling of the high-temperature exhaust gas.

The anti-swing guide vane 15 is driven by an electric mechanism so that the angle between the guide vane 15 and the exhaust passage 16 in the horizontal direction is 0° to 5°, and at the same time the cross-sectional area of the exhaust passage 16 is changed; when the ship engine load is less than 30%, To increase the flow rate of exhaust gas entering the tower at low load, the horizontal angle between the guide vanes 15 and the exhaust channel 16 is 10° to 15°, and the cross-sectional area of the exhaust channel 16 is reduced by 20% to 30%; when the ship swings beyond 10°, In order to slow down the phenomenon of uneven distribution of exhaust gas velocity field, concentration field, temperature field, etc. caused by ship swinging into the compact high-efficiency mass transfer scrubber 2, the anti-swing guide vane 15 drives the guide vane 15 and the exhaust channel through an electric mechanism 16 The included angle in the horizontal direction is 0°~5°.

In order to prevent the downward washing liquid in the compact high-efficiency enhanced mass transfer scrubber 2 from entering the connecting tail gas channel 16, a rain shield 18 is provided at the connection between the connecting channel and the compact high-efficiency enhanced mass transfer scrubber 2. The rain shield 18 has an angle of 80° with the vertical downward direction of the compact high-efficiency mass transfer scrubber 2, and a length of 200 to 500 mm.

The multi-zone enhanced mass transfer layer 21 is composed of liquid-holding zones 211 divided into a plurality of small hole corrugated plates. After the ship exhaust gas passes through the liquid-holding area 211 of the small-hole corrugated plate, it contacts the washing liquid to strengthen the turbulent mixing of gas and liquid, and forms a liquid-holding layer of a certain height, which further strengthens the gas-liquid absorption and mass transfer contact time, and improves the pollutant removal efficiency; as described The liquid-holding plate is provided with openings 213. The hole shape 213 of the openings 213 is preferably a "round hole" or a "herringbone" shape; further preferably, the circular hole diameter is 15 mm to 25 mm, and the opening rate is 25% to 35%. %; the side length of the "herringbone" hole is 5mm to 8mm, and the opening rate is preferably 25% to 30%; in order to reduce the uneven height distribution of the liquid-holding layer of the multi-zone enhanced mass transfer layer 21 caused by ship swings, corrugated small holes are preferred The height of the liquid holding plate 212 in the plate liquid holding area 211 is 200 mm to 300 mm.

The liquid phase regrouping and redistribution ring 22 is arranged below the spray pipe 232, connected to the wall weld of the compact high-efficiency mass transfer scrubbing tower at a certain angle, and has holes to redisperse the descending liquid droplets into small liquids. Drops, liquid phase re-aggregation and redistribution - increase the gas flow rate, increase the spray coverage, increase the density of the droplets, further improve the sulfur dioxide absorption efficiency, and reduce the exhaust gas escaping from the wall when the ship swings and the pollutants caused by uneven distribution of the washing liquid The removal efficiency is unstable.

Preferably, the liquid phase reaggregation and redistribution ring 22 is arranged at 800 mm to 1000 mm below the spray pipe 232; the area ratio of the liquid phase reaggregation and redistribution ring 22 to the compact high-efficiency mass transfer scrubber is preferably 5% to 10%. The angle with the wall of the compact high-efficiency mass transfer scrubber is preferably 45° to 60°, the pore diameter of the liquid phase reaggregation and redistribution ring 22 is preferably 20 mm to 30 mm, and the opening rate is preferably 30% to 45%.

In order to alleviate the problem of unstable desulfurization efficiency caused by large ship swings in sea conditions such as storms and waves, 3 to 5 liquid-gas ratio control layers 23 are set up to form a multi-dimensional and multi-scale ship exhaust gas capture network; at the same time, in order to ensure the washing liquid uniformity and reduce the possibility of ship exhaust gas escaping, the single-layer liquid-gas ratio control area is divided into liquid-gas ratio control sub-areas, and the sub-area nozzles 234 adopt anti-swing and ultra-fine particle size atomization nozzles to maximize the Large washing liquid spray coverage. The liquid-gas ratio control layer 23 is connected to the spray main pipe 232 with an electric valve. The spray main pipe 232 is connected to the washing liquid frequency conversion circulation pump 231 to achieve compact, efficient and enhanced transmission under different navigation areas and loads. The liquid-gas ratio in the quality scrubber 2 can be flexibly adjusted.

In order to reduce the angle between the atomized washing liquid droplets and the upward ship exhaust gas caused by the ship swinging and other navigation environment, and slow down the decrease in spray coverage caused by the ship swinging and other navigation environment, the spray angle deviation of the sub-area nozzle 234 is preferably ±5 %~10%, the median diameter of the nozzle atomized droplet volume (Dv0.5) should be less than 500 μm.

The vortex agglomeration device 24 is arranged at the upper end of the liquid-gas ratio control layer 23 and consists of even-numbered rows of alternately arranged rounded "Z" and reverse "Z" type spoilers 241, with a flow angle of 30°. , the ends of the rounded "Z" and reverse "Z" type spoilers are regularly arranged with saw teeth of the same size. The shape of the saw teeth is preferably triangular or rectangular. The total length of the spoiler section is 1000~1500mm; after purification, it carries dust and carbon When the tail gas of liquid droplets such as black particles flows through the spoiler, a large number of eddies of different sizes can be generated in different directions in the compact high-efficiency mass transfer scrubber, effectively promoting collision and agglomeration between liquid droplets and particles, and promoting The liquid droplets carried in the ship exhaust gas grow up, collide and separate, and strengthen the removal of pollutants such as carbon black and PAHs in the ship exhaust gas.

The high-temperature exhaust gas enters the pre-washing and cooling section 11, contacts the spray atomized droplets of the first cooling spray pre-washing layer 141, and increases its speed through the turbulence-enhanced mixing section 12, forming a strengthened turbulence area to strengthen the rapid cooling of the high-temperature exhaust gas, and the high temperature after cooling The exhaust gas is decelerated after entering the cooling rectification section 13. The inertial force of the droplets is increased through turbulence, and the temperature of the exhaust gas increases the thermophoretic force of the droplets. The difference in droplet speed increases the probability of collision between droplets, causing small droplets and dust particles to grow and settle. The large liquid droplets and dust particles are separated into gas and liquid after passing through the tail gas channel 16 in front of the compact high-efficiency mass transfer scrubber 2, and the separated pollutant droplets enter the liquid collection area 26 through the tail gas channel 16;

According to different navigation needs, the exhaust gas pre-washing turbulent temperature control section 1 includes more than one exhaust gas pre-wash turbulent temperature control section branch to achieve rapid cooling of high-temperature exhaust gas, facilitate flexible control of the tail gas flow field entering the tower, and achieve rapid cooling of high-temperature exhaust gas;

The ship exhaust gas is cooled by the exhaust gas pre-washing turbulent temperature regulating section 1 and then enters the multi-zone enhanced mass transfer layer 21 through the anti-swing guide vane 15. The small droplets of the washing liquid contact the ship exhaust gas and tumble under high-speed airflow conditions. The turbulent flow mixes and forms The liquid-holding layer strengthens the gas-liquid absorption and mass transfer contact time, improves the absorbent utilization rate, and improves the pollutant removal efficiency; in order to reduce the multi-zone enhanced mass transfer layer 21 caused by ship swings, the height of the liquid-holding layer is unevenly distributed, and the small holes The corrugated plate liquid holding area 211 has a liquid holding plate 212 of a certain height;

After the ship exhaust gas flows up into the liquid phase reaggregation and redistribution ring 22, the openings in the liquid phase reaggregation and redistribution ring 22 redisperse the downward droplets into small droplets, and the liquid phase reaggregation and redistribution increases the gas flow rate and increases The spray coverage rate increases the density of droplets, further improves the sulfur dioxide absorption efficiency, and reduces the instability of pollutant removal efficiency caused by exhaust gas escaping from the wall when the ship swings and uneven distribution of washing liquid;

The ship exhaust gas continues up to the liquid-gas ratio control layer 23 to form a liquid-gas ratio control area, forming a multi-dimensional and multi-scale ship exhaust gas capture network to achieve exhaust gas purification; at the same time, the liquid-gas ratio control sub-area nozzle 234 adopts anti-swing and ultra-fine particle diameter atomizing nozzle to maximize the washing liquid spray coverage;

When the purified tail gas carrying droplets such as dust and carbon black particles flows through the vortex agglomeration device 24, it can generate a large number of vortices of different sizes in different directions in the compact high-efficiency mass transfer scrubber 2, effectively promoting the separation of droplets and particles. The collision and reunion between the droplets in the ship's exhaust promote the collision and separation of the liquid droplets carried in the ship's exhaust, and strengthen the removal of pollutants in the ship's exhaust. The mist droplets are further removed by the demister 25 and then discharged into the atmospheric environment through the tower top chimney;

The multi-factor flexible control system 3 is used to monitor the factors affecting the sulfur dioxide efficiency in the circulation tank 32 through the monitoring device 34, and the pH, temperature and liquid phase components of the washing liquid are flexibly controlled through the detergent switching device, and further switched through the pipeline The device 233 realizes flexible regulation of the liquid-gas ratio in the compact high-efficiency mass transfer scrubber 2, comprehensive liquid-gas ratio, multi-factor regulation of scrubbing liquid pH, temperature and concentration, achieving efficient, stable and low-cost removal of SO ₂ while improving the individual The scrubber uses a variety of absorbents for its adaptability, safety and reliability.

Example 2

A container ship has a rated power of 16440kW, a flue gas volume of 40kg/s, and a container carrying capacity of 2680t. The route is from Alexandria, Egypt to Piraeus, Greece. It burns marine fuel oil with a sulfur content of 3.0%. When the ship sails to the Emission Control Area (ECA) At that time, the ship load rate was floating at 87%. After denitration, the temperature of the ship exhaust before entering the pre-washing cooling layer was 320-350°C, the SO ₂ concentration was 2000 ppm, and the concentration of particulate matter and PAHs was about 10 ppm. After passing through the turbulence-enhanced mixed layer After rapid temperature adjustment, more than 95% of the carbon black particles and PAHs in the ship exhaust gas were captured and pre-washed and removed. The temperature entering the compact high-efficiency enhanced mass transfer scrubber was 120-130°C, and the liquid redistribution component was further combined to enhance gas-liquid mixing. - A compact and efficient scrubber with flexible control of the liquid-to-gas ratio, using magnesium hydroxide slurry as the detergent. The pH value of the detergent solution is between 5.8 and 6.0, the magnesium-sulfur molar ratio is 1.03, the scrubbing liquid-to-liquid ratio is 6L/Nm ³ , and the temperature About 45°C; combined with the system in Embodiment 1, the anti-swing guide vane 15 is driven by an electric mechanism to form an angle between the guide vane 15 and the exhaust gas channel 16 in the horizontal direction of 0° to 5°, and the hole pattern provided on the liquid holding plate 213 is a "herringbone" shape, the "herringbone" hole side length is 8mm, the opening rate is preferably 30%, the height of the liquid holding plate 212 in the small hole corrugated plate liquid holding area 211 is 200mm, the liquid phase is gathered and redistributed in the ring 22 is arranged 800mm below the spray pipe 232; the area ratio of the liquid phase reaggregation and redistribution ring 22 to the compact high-efficiency mass transfer scrubber 2 is preferably 10%, and the angle between the wall of the compact high-efficiency mass transfer scrubber 2 is preferably 60°. , the aperture of the liquid phase reaggregation and redistribution ring 22 is preferably 30mm, the opening rate is preferably 30%, three layers of liquid-gas ratio control layer 23 are provided, the spray angle deviation of the sub-region nozzle 234 is preferably ±5%, and the nozzle atomizes liquid droplets The median volume diameter (Dv0.5) is 400 μm. It consists of 6 rows of alternately arranged rounded "Z" and reverse "Z" type spoilers 241. The spoiler angle is 30°, and the rounded "Z" and The end of the anti-"Z" type spoiler is regularly arranged with rectangular saw teeth of the same size. The total length of the spoiler section is 1000mm, which solves the problem of efficient and stable desulfurization under working conditions such as tower swing (up to 20°) and improves desulfurization efficiency. It can reach more than 99.8%, the SO ₂ concentration is 4.5ppm, and the SO ₂ (ppm)/CO ₂ (%) is 1.26, which is better than the most stringent requirements of IMO.

Example 3

A container ship has a rated power of 19810kW and a flue gas volume of 60kg/s. The route is from Aqaba, Jordan to Djibouti. It burns marine fuel oil with a sulfur content of 0.1%. When the ship sails to the Emission Control Area (ECA), the ship load factor is 71.4% floating. After denitration, the temperature of the ship exhaust gas before entering the pre-washing cooling layer is 300~320°C, the SO ₂ concentration is 67 ppm, and the concentration of particulate matter and PAHs is about 8 ppm. After rapid temperature adjustment through the turbulence-enhanced mixing layer, it is achieved More than 95% of the carbon black particles and PAHs in the ship exhaust are captured, pre-washed and removed. The temperature entering the compact and efficient enhanced mass transfer scrubber is 110-120°C. It is further combined with liquid redistribution components to enhance gas-liquid mixing and flexible control of the liquid-gas ratio. The compact and efficient scrubber uses seawater as the detergent. The pH value of the detergent solution is 7.5 to 8.0, the total alkalinity is about 2.8mmol/L, the temperature is 20 to 25°C, and the washing liquid liquid to gas ratio is 12L/Nm ³ ; combined with In the system in Embodiment 1, the anti-swing guide vane 15 is driven by an electric mechanism to form an angle between the guide vane 15 and the exhaust passage 16 in the horizontal direction of 0° to 5°, and the hole pattern 213 provided on the liquid retaining plate is a "herringbone"" shape, the side length of the "herringbone"-shaped hole is 6mm, the opening rate is preferably 25%, the height of the liquid-holding plate 212 in the liquid-holding area 211 of the small hole corrugated plate is 300mm, and the liquid phase reintegration and redistribution ring 22 is arranged in the spray 900mm below the tube 232; the area ratio of the liquid phase reaggregation redistribution ring 22 to the compact high-efficiency mass transfer scrubber 2 is preferably 15%, and the angle between the wall of the compact high-efficiency mass transfer scrubber 2 is preferably 45°, and the liquid phase reaggregation is The aperture of the redistribution ring 22 is preferably 20 mm, the opening rate is preferably 40%, three layers of liquid-gas ratio control layer 23 are provided, the spray angle deviation of the sub-region nozzle 234 is preferably ±8%, and the median diameter of the nozzle atomized droplet volume is ( Dv0.5) 450μm, consisting of 6 rows of alternatingly arranged rounded “Z” and reverse “Z” type spoilers 241, with a flow angle of 30°, rounded “Z” and reverse “Z” shapes The end of the spoiler is regularly arranged with rectangular saw teeth of the same size. The total length of the spoiler section is 1200mm, which solves the problem of efficient and stable desulfurization under working conditions such as tower swing (up to 20°), and the desulfurization efficiency can reach more than 97%. , SO ₂ concentration is 2.0ppm, SO ₂ (ppm)/CO ₂ (%) is 0.95, which is better than the most stringent requirements of IMO.

Example 4

A container ship has a rated power of 42350kW and a flue gas volume of 108.75kg/s. The route is from RIGA, Latvia to BREMERHAVEN, Germany. It burns marine fuel oil with a sulfur content of 3.0%. When the ship sails to the Emission Control Area (ECA), the ship load The rate fluctuates between 20% and 98%. Referring to Figure 8, the difference between this embodiment and Embodiment 1 and 2 is that the pre-washing turbulent temperature-regulating section adopts dual exhaust gas pre-washing turbulent temperature-regulating sections, and the ship exhaust gas enters before the pre-washing cooling layer after denitration. The temperature is 340~360℃, the _SO2 concentration is 2000ppm, and the concentration of particulate matter and PAHs is about 15ppm. After rapid temperature adjustment of the turbulence-enhanced mixed layer, more than 96% of the carbon black particles and PAHs in the ship exhaust are captured and pre-washed. In addition, the temperature entering the compact high-efficiency enhanced mass transfer scrubber is 95 to 100°C. The compact high-efficiency scrubber is further combined with liquid redistribution components to strengthen gas-liquid mixing and flexible control of the liquid-gas ratio. Magnesium hydroxide slurry is added as a scrubber. The pH value of the detergent solution is between 5.8 and 6.0, the molar ratio of magnesium to sulfur is 1.02, the liquid-to-gas ratio of the washing liquid is 5.5L/Nm ³ , and the temperature is about 42°C; combined with the system in Example 1, the tower body swing (up to 20° ) and other working conditions, the desulfurization efficiency can reach more than 99.8%, the SO ₂ concentration is 4.5ppm, and the SO ₂ (ppm)/CO ₂ (%) is 1.20, which is better than the most stringent requirements of IMO.

Comparative example 1

A container ship has a rated power of 19890kW and a flue gas volume of 60kg/s. The route is from Aqaba, Jordan to Djibouti. It uses marine fuel oil with a sulfur content of 0.1%. When the ship sails to the Emission Control Area (ECA), the ship load factor is 70% floating. The temperature of the ship exhaust gas before entering the pre-washing cooling layer after denitration is 310-330°C, the _SO2 concentration is 80 ppm, and the concentration of particulate matter and PAHs is about 10 ppm. This embodiment does not use the multi-zone enhanced transmission described in the present invention. The mass layer 21, the liquid phase reaggregation and redistribution ring 22 and the vortex agglomeration device 24 use seawater as the detergent. The pH value of the detergent solution is 7.5~8.0, the total alkalinity is about 2.8mmol/L, and the temperature is 20~25°C. As a result, the liquid-to-gas ratio of the washing liquid reaches 14L/Nm ³ , which is approximately 17% higher than in Example 3. At the same time, the anti-swing guide vane 15 is not provided, and the spray angle deviation of the sub-region nozzle 234 exceeds ±11%. The median diameter of the nozzle atomized droplet volume (Dv0.5) reaches 1000 μm. It is difficult to achieve high efficiency and stability of pollutants under working conditions such as the tower swinging (up to 20°) when the ship is in strong wind and waves. The desulfurization efficiency is only 80%, SO ₂ concentration is about 14 ppm, SO ₂ (ppm)/CO ₂ (%) is 4.36, which does not meet the requirements of IMO.

Comparative example 2

Referring to Embodiment 2, the hole pattern 213 provided on the liquid-holding plate is in the shape of a "herringbone", with a side length of 5 mm and an opening rate of 40%. The liquid-holding plate in the liquid-holding area 211 of the corrugated plate with small holes is 212 has a height of 50mm, and the liquid phase reaggregation and redistribution ring 22 is arranged 500mm below the spray pipe 232; the area ratio of the liquid phase reaggregation and redistribution ring 22 to the compact high-efficiency mass transfer scrubber 2 is 10%, which is 10% higher than that of the compact high-efficiency mass transfer scrubber 2. The angle between the 2 walls of the mass transfer scrubbing tower is 70°. The liquid phase regrouping and redistribution ring 22 has an aperture of 45mm and an opening rate of 60%. There are three layers of liquid-gas ratio control layer 23. The injection angle deviation of the sub-region nozzle 234 is ± 15%, the median diameter of the nozzle atomized droplet volume (Dv0.5) is 600 μm, consisting of 6 rows of alternately arranged rounded "Z" and reverse "Z" type spoilers 241, with a flow angle of 45 °, the ends of the rounded "Z" and reverse "Z" type spoilers are regularly arranged with rectangular saw teeth of the same size. The total length of the spoiler section is 1000mm. It is difficult to cause the tower body to swing when the ship is in strong wind and waves (up to 20°) and other working conditions, the desulfurization efficiency is only 85%, the SO ₂ concentration is 30 ppm, and the SO ₂ (ppm)/CO ₂ (%) is 4.35.

Claims (6)

1. A ship tail gas washing and purifying system suitable for swinging/starting and stopping complex working conditions is characterized in that: the system comprises a communicated tail gas pre-washing turbulence temperature regulation section, a compact high-efficiency enhanced mass transfer washing tower and a multi-factor flexible regulation system;

the tail gas pre-washing turbulence temperature regulating section comprises more than one tail gas pre-washing turbulence temperature regulating section branch, the tail gas pre-washing turbulence temperature regulating section branch comprises a pre-washing temperature reducing section, a turbulence strengthening mixing section and a temperature reducing rectifying section which are sequentially arranged from top to bottom, a first temperature reducing spraying pre-washing layer is arranged at the inlet end of the pre-washing temperature reducing section, and a second temperature reducing spraying pre-washing layer is arranged at the upper end of the turbulence strengthening mixing section;

the tail gas pre-washing turbulence temperature adjusting section is communicated with a tail gas channel, and an anti-swing guide vane is arranged in the tail gas channel;

the compact efficient reinforced mass transfer washing tower comprises a liquid collecting area, a multi-region reinforced mass transfer layer suitable for swinging, a liquid phase back-focusing redistribution ring suitable for swinging, a liquid-gas ratio regulating layer suitable for swinging, a vortex agglomerating device and a demister which are sequentially arranged from bottom to top, wherein the multi-region reinforced mass transfer layer suitable for swinging consists of a plurality of small-hole corrugated plate liquid holding areas, the liquid-gas ratio regulating layer suitable for swinging comprises a variable-frequency circulating pump, a spray pipe, an anti-swinging nozzle and a pipeline switching device, and the anti-swinging nozzle is arranged on the spray pipe and is communicated with the spray pipe through the pipeline switching device;

The multi-factor flexible regulation and control system comprises a washing liquid circulating tank, a washing agent adding pipeline, a seawater pipeline, a monitoring device and a washing agent switching device, wherein the washing liquid circulating tank is respectively connected with the washing agent switching device and the monitoring device, the washing liquid circulating tank is communicated with a spray pipe through a variable-frequency circulating pump and the pipeline switching device, and the washing agent switching device is respectively communicated with the washing agent adding pipeline and the seawater pipeline;

the first cooling spraying pre-washing layer comprises a plurality of sections of Venturi type spraying main pipes, cooling spraying branch pipes with the same pipe diameters in a staggered mode, first cooling nozzles and second cooling nozzles, the first cooling nozzles correspond to the cooling spraying branch pipes with the same pipe diameters in a staggered mode one by one, the starting end of each Venturi type spraying main pipe is provided with one second cooling nozzle, and the first cooling nozzles and the second cooling nozzles are unidirectional 90-degree or 120-degree solid spiral cone nozzles;

the second cooling spraying pre-washing layer comprises a same-diameter spraying main pipe, cooling spraying branch pipes which are distributed in a same-diameter staggered manner and third cooling nozzles, and the third cooling nozzles are in one-to-one correspondence with the cooling spraying branch pipes which are distributed in the same-diameter staggered manner; the third cooling nozzle is a bidirectional 90-degree or 120-degree solid cone nozzle;

The liquid holding area of the small-hole corrugated plate comprises a liquid holding plate, wherein the liquid holding plate is provided with an opening, and the hole type of the opening is a round hole or a herringbone hole; the circular aperture is 15 mm-25 mm, and the aperture ratio is 25% -35%; the lambdoidal shape Kong Bianchang mm-8 mm and the aperture ratio is 25% -30%; the height of the liquid holding plate is 200-300 mm;

the liquid phase back-polymerization redistribution ring is connected with the welding seam of the inner wall of the shell of the compact high-efficiency reinforced mass transfer washing tower at a certain angle, and is arranged at the position 800-1000 mm below the spray pipe; the area ratio of the liquid phase back-polymerization redistribution ring to the compact high-efficiency enhanced mass transfer washing tower is 5-10%, the included angle between the liquid phase back-polymerization redistribution ring and the inner wall of the shell of the compact high-efficiency enhanced mass transfer washing tower is 45-60 degrees, the aperture of the liquid phase back-polymerization redistribution ring is 20-30 mm, and the aperture ratio is 30-45%;

the compact high-efficiency reinforced mass transfer washing tower is characterized in that a steady flow design is carried out on a multi-region reinforced mass transfer layer, a liquid phase back-polymerization redistribution ring, a liquid-gas ratio regulation and control region and a vortex agglomeration demisting region, so that the liquid-gas ratio can be reduced by more than 10% to achieve the same desulfurization efficiency, and the economic operation of a desulfurization system is facilitated;

the pH, temperature and liquid phase components of the washing liquid in the circulating tank are monitored by a monitoring device by adopting a multi-factor flexible regulation and control system, the pH, temperature and liquid phase components of the washing liquid are flexibly regulated and controlled by a detergent switching device, and the flexible regulation and control of the liquid-gas ratio in the compact high-efficiency enhanced mass transfer washing tower is realized by the pipeline switching device;

When seawater is used as a detergent, the pH value of the detergent solution is controlled to be 7.5-8.3, the total alkalinity is 2.0-3.0 mmol/L, and the liquid-gas ratio of the detergent solution is not less than 10L/Nm ³ The temperature is preferably controlled between 15 and 30 ℃;

when the magnesium hydroxide slurry is used as a detergent, the pH value of the detergent solution is controlled to be 5.0-6.5, the molar ratio of magnesium to sulfur is not more than 1.05, and the liquid-gas ratio of the detergent solution is more than 5L/Nm ³ The temperature is controlled between 40 and 52 ℃.

2. The marine vessel exhaust gas cleaning and purifying system suitable for swing/start-stop complex conditions according to claim 1, wherein: the anti-swing guide vane drives the guide vane to form an included angle of 0-5 degrees with the horizontal direction of the tail gas channel through the electric mechanism, and meanwhile, the cross-sectional area of the tail gas channel is changed; when the load of the ship engine is lower than 30%, the included angle between the guide vane and the horizontal direction of the tail gas channel is 10-15 degrees, and the cross section area of the tail gas channel is reduced by 20-30%; when the ship swings by more than 10 degrees, the swing-preventing guide vane drives the guide vane to form an included angle of 0-5 degrees with the horizontal direction of the tail gas channel through the electric mechanism.

3. The marine vessel exhaust gas cleaning and purifying system suitable for swing/start-stop complex conditions according to claim 1, wherein: the number of the liquid-gas ratio regulating layers is 3-5, the single-layer liquid-gas ratio regulating layer comprises a plurality of liquid-gas ratio regulating subareas, the spray angle deviation of the nozzles of the subareas is +/-5% -10%, the nozzles of the subareas adopt anti-swing and superfine particle diameter atomizing nozzles, and the median diameter of the atomized liquid drops of the nozzles is smaller than 500 mu m.

4. The marine vessel exhaust gas cleaning and purifying system suitable for swing/start-stop complex conditions according to claim 1, wherein: the vortex agglomerating device comprises even-numbered rows of round angle Z-shaped and inverted Z-shaped spoilers which are alternately arranged, the incident flow angle of the spoilers is 30 degrees, the tail ends of the round angle Z-shaped spoilers and inverted Z-shaped spoilers are regularly arranged with saw teeth with the same size, the saw teeth are triangular or rectangular, and the total length of the spoilers is 1000-1500 mm.

5. A method for cleaning and purifying marine vessel exhaust gas by the system according to any one of claims 1-4, characterized by comprising the steps of:

the high-temperature tail gas enters a pre-washing cooling section and contacts with spray atomization liquid drops of a first cooling spray pre-washing layer, a turbulent flow reinforced mixing section is used for accelerating, a reinforced turbulent flow area is formed for reinforcing rapid cooling of the high-temperature tail gas, the cooled high-temperature tail gas enters a cooling rectifying section and is decelerated, the inertia force of the liquid drops is improved through turbulent flow, the temperature of the tail gas is improved, the collision probability among the liquid drops is improved through speed difference of the liquid drops, fine liquid drops and dust particles are promoted to grow and settle, the grown liquid drops and dust particles are subjected to gas-liquid separation after passing through a tail gas channel in front of a compact high-efficiency reinforced mass transfer washing tower, and separated pollutant liquid drops enter a liquid collecting area through the tail gas channel;

According to different sailing requirements, the tail gas pre-washing turbulence temperature regulating section comprises more than one tail gas pre-washing turbulence temperature regulating section branch so as to realize the rapid cooling of the high-temperature tail gas, and the flow field of the tail gas entering the tower is convenient to flexibly regulate and control, so that the rapid cooling of the high-temperature tail gas is realized;

the ship tail gas enters a multi-region reinforced mass transfer layer through an anti-swing guide vane after being cooled by a tail gas pre-washing turbulence temperature adjusting section, small washing liquid drops are contacted with the ship tail gas and roll under the high-speed airflow condition, turbulent flow is mixed to form a liquid holding layer, the gas-liquid absorption mass transfer contact time is prolonged, the utilization rate of an absorbent is improved, and the pollutant removal efficiency is improved; in order to reduce uneven height distribution of liquid-holding layers of multi-region reinforced mass transfer layers caused by ship swing, the liquid-holding areas of the small-hole corrugated plates are provided with liquid-holding plates with certain heights;

after the ship tail gas goes into the liquid phase back-aggregation redistribution ring, the descending liquid drops are redispersed into small liquid drops through the openings on the liquid phase back-aggregation redistribution ring, the liquid phase back-aggregation redistribution is used for improving the gas flow rate, increasing the spray coverage rate, improving the density of the liquid drops, further improving the sulfur dioxide absorption efficiency, and reducing the phenomena of unstable pollutant removal efficiency caused by tail gas adherence escape and uneven washing liquid distribution during ship swing;

The ship tail gas continues to ascend to the liquid-gas ratio regulating layer to form a liquid-gas ratio regulating area, so as to form a multi-dimensional multi-scale ship tail gas trapping network and realize tail gas purification; meanwhile, in order to ensure the uniformity of the washing liquid and reduce the possibility of ship tail gas escape, the single-layer liquid-gas ratio regulating layer comprises a plurality of liquid-gas ratio regulating sub-areas, and nozzles of the sub-areas adopt anti-swing and ultrafine particle diameter atomizing nozzles so as to increase the spraying coverage rate of the washing liquid to the greatest extent;

when the purified tail gas carrying liquid drops containing dust, carbon black particles and the like flows through the vortex agglomerating device, a large amount of vortices with different dimensions can be generated in different directions in the compact efficient enhanced mass transfer washing tower, collision and agglomeration between the liquid drops and the particles are effectively promoted, the growth, collision and separation of the liquid drops carried in the ship tail gas are promoted, the removal of pollutants in the ship tail gas is enhanced, and the mist drops are further removed through a demister and then discharged outside a tower top chimney to enter the atmosphere;

the system is characterized in that a multi-factor flexible regulation and control system is adopted to monitor factors influencing sulfur dioxide efficiency in the circulating tank through a monitoring device, flexible regulation and control of pH, temperature and liquid phase components of a washing liquid are realized through a detergent switching device, flexible regulation and control of liquid-gas ratio in the compact efficient enhanced mass transfer washing tower is further realized through a pipeline switching device, multi-factor regulation and control of pH, temperature and concentration of the washing liquid are integrated, and SO is realized ₂ High efficiency, stability and low cost, and improves the adaptability and the safety and reliability of using a plurality of absorbents by a single washing tower.

6. The method for washing and purifying ship exhaust gas by using the system according to claim 5, wherein: the tail gas pre-washing turbulence temperature regulating section and the compact high-efficiency reinforced mass transfer washing tower are arranged in a compact U-shaped or W-shaped structure.