WO2023060946A1

WO2023060946A1 - System and method for incinerating oil sludge by using power station pulverized coal boiler

Info

Publication number: WO2023060946A1
Application number: PCT/CN2022/102023
Authority: WO
Inventors: 汪华剑; 马翔; 邓玲恵; 王洋; 房凡; 吴庆龙; 陈煜�; 徐党旗; 刘笑; 周军
Original assignee: 西安热工研究院有限公司
Priority date: 2021-10-15
Filing date: 2022-06-28
Publication date: 2023-04-20
Also published as: CN113819469A

Abstract

A system and a method for incinerating oil sludge by using a power station pulverized coal boiler. The system comprises a boiler (1), an air preheater (2), an air feeder (3), a primary fan (4), a flue gas purification device (5), a coal mill (9), a separator (10), a combustion system (11), a coal bin (12), a coal conveying belt (13), a spiral stirrer (14) and a mixer feeding port (15). By means of the method, without providing any intermediate oil sludge incineration device, oil sludge can be directly mixed with raw coal after a certain pretreatment is carried out on the oil sludge; a mixture is crushed by means of an existing powdering system of the boiler (1) and conveyed into a hearth of the boiler (1) for incineration; and then purification is carried out by means of an existing flue gas purification device of the boiler (1), thereby utilizing the oil sludge and realizing treatment on the oil sludge to make same harmless.

Description

System and method for incinerating oil sludge using pulverized coal boiler in power station

Cross References to Related Applications

This application claims the priority of the Chinese patent application submitted to the China Patent Office on October 15, 2021, with the application number 202111205644.0, and the title of the invention is "A System and Method for Burning Oil Sludge Using Power Plant Pulverized Coal Boiler", the entire content of which is passed Incorporated herein by reference.

technical field

The application belongs to the technical field of coal-fired boilers, and in particular relates to a system and method for incinerating oil sludge using a pulverized coal boiler of a power station.

Background technique

Oil sludge is one of the main solid wastes generated during the exploitation, transportation and utilization of petroleum and biomass oil. Since oil sludge is a hazardous waste with stable structure and difficult to handle, it cannot be disposed of by simple landfill method like traditional waste. Existing oil sludge treatment technologies mainly include: incineration, centrifugal separation, solvent extraction, and biological methods, among which incineration is the lowest cost and most widely used method. The traditional oil sludge incineration treatment is mainly carried out by establishing a dedicated incinerator separately. On the one hand, with the increasingly stringent environmental protection regulations, the difficulty of incinerator construction approval is increasing, and the construction cost is increasing day by day. On the other hand, the temperature of the incineration process is relatively low, and there may be organic pollutants such as dioxins in the flue gas generated at the furnace outlet, and the dioxins in the exhausted flue gas The content of dust, NOx and SOx is generally much higher than the ultra-low emission standard required by the current environmental protection, which will cause great pollution to the surrounding environment.

There are a huge number of pulverized coal power plant boilers distributed in different regions of the country. Using pulverized coal power plant boilers to treat oil sludge is a solution with low processing cost and high comprehensive benefits. Using this solution to deal with oil sludge, on the one hand, can save the problem of high construction cost of incinerators; on the other hand, pulverized coal power plant boilers have the characteristics of high combustion temperature, high combustion efficiency and high thermal efficiency, which can greatly improve the heat utilization efficiency of oil sludge, and Power plant boilers have already built ultra-low emission environmental protection facilities for flue gas, which can achieve ultra-low emission of dust, NOx and SOx in the flue gas. However, oil sludge has physical and chemical properties that are very different from raw coal. How to embed the transportation and combustion control of oil sludge in the existing pulverized coal power plant boiler system to form a system and method that can solve the problem of burning oil sludge in power plant pulverized coal boilers, especially Whether or not the existing boiler system can meet the incineration needs of oil sludge is also an important subject that needs to be studied urgently.

Contents of the invention

The purpose of this application is to provide a system and method for incinerating oil sludge using a pulverized coal boiler in a power station. Under the condition of not installing an intermediate oil sludge incineration device, the oil sludge can be directly mixed with raw coal after a certain pretreatment, and passed through the boiler The existing pulverizing system is crushed and transported into the furnace of the boiler for incineration, and then purified by the existing flue gas purification device of the boiler to realize the utilization and harmless treatment of oil sludge.

The application is realized through the following technical solutions:

A method for burning oil sludge using a pulverized coal boiler of a power station, comprising the steps of:

Step 1, according to the analysis of the characteristics of the sludge, configure the sludge conditioner, and use the configured conditioner to modify the sludge with strong volatility and high water content;

Step 2, feed the oil sludge and the prepared conditioning agent into the mixer respectively, fully stir them evenly in the mixer, use the conditioning agent to modify the oil sludge, reduce the physical properties and volatility of the liquid flow of the oil sludge, and make it Similar solid properties to raw coal;

Step 3. Send the oil sludge after conditioning to the raw coal conveyor belt, and blend it with the raw coal on the coal conveyor belt according to the set ratio. The mass ratio of the blend is determined by the best ratio obtained from the blending test. ;

Step 4. The mixed oil sludge and raw coal are sent to the existing pulverization system for pulverization, and then sent to the furnace of the pulverized coal power plant boiler through the powder feeding system for high-temperature incineration. The incineration process is a mixed combustion process of coal powder and oil sludge powder The temperature is controlled in the range of 1300-1600 ℃ to ensure the harmless treatment of harmful substances in the oil sludge, and the control of the mixed combustion process is adjusted in conjunction with the optimization control of the entire boiler combustion;

Step 5, the dust, NOx and SOx pollutants produced by the combustion of raw coal and oil sludge in the boiler are purified through the denitrification, dust removal and desulfurization devices arranged in the flue at the tail of the boiler.

The further improvement of the present application is that in step 1, the formulation of the conditioner is based on the specific indicators of the moisture and volatile content of the oil sludge, and the quicklime, fly ash and kaolin are used to configure according to the mass percentage, and the proportion of the configuration is mainly quicklime, accounting for 50-60%, fly ash accounts for 20-40%, and other minerals such as kaolin account for 10-20%. The final proportion of each component is determined by the composition characteristics of the oil sludge. The thermal gravimetric analysis experiment effect of oil sludge modification is confirmed by comparison.

The further improvement of the present application lies in that in step 2, the oil sludge is modified with a conditioning agent, and a custom-made modulator is added based on favorable physical and chemical characteristics indicators to improve the fluidity and volatile characteristics of the oil sludge, specifically including After adding the preparation agent, the mud state with a high water content that is not suitable for storage is transformed into a solid state similar to coal with a water content below 20%, which is easy to store and transport. On the other hand, those volatile and flammable components are also contained in the preparation agent. Adsorbed by the porous modulator, the volatile performance is greatly reduced, and the mass ratio of the modulator is 20-30%.

The further improvement of the present application is that in step 3, the tempered oil sludge and raw coal are blended on the coal conveyor belt according to the set ratio, and the mass ratio of the oil sludge that can be blended on the coal conveyor belt does not exceed 20%. .

A system for incinerating oil sludge using a pulverized coal boiler in a power station, including a boiler, an air preheater, a blower, a primary fan, a flue gas purification device, a coal mill, a separator, a combustion system, a coal bunker, a coal conveyor belt, and a spiral agitator Device and mixer inlet;

Among them, the heat generated by the combustion of fuel in the boiler passes through the heat exchange surface, and the secondary air and primary air sent by the blower and the primary fan are heated by the air preheater, and the heated secondary air passes through the organization of the boiler combustion system. , to supplement oxygen for the combustion of fuel in the furnace; the high-pressure head hot primary air sent by the primary fan is sent to the coal mill through the pipeline, and the raw coal and oil sludge mixture in the coal mill are dried and transported;

Sludge and conditioning agent are respectively added to the feed inlet of the mixer at the entrance of the spiral agitator, and then the sludge and conditioning agent are stirred in the spiral agitator and mixed evenly and tempered, and the conditioned sludge is transported to Blending is carried out on the coal conveyor belt; the mixture of coal and oil sludge is sent to the coal bunker through the coal conveyor belt, and the mixture of raw coal and coal slime in the coal bunker is sent to the coal mill through the coal drop pipe, and after grinding and drying, Carried by the primary air, it enters the pulverized coal separator, and the pulverized coal separator transports the pulverized coal and oil sludge powder with qualified particle size to the combustion system through the powder delivery pipeline, and sends them into the boiler for combustion under the organization of the combustion system; the combustion produces The dust, NOx and SOx pollutants are purified by the dust removal, denitrification and desulfurization devices included in the flue gas purification device arranged on the tail flue.

A further improvement of the present application is that the flue gas purified from air pollutants is discharged through the chimney.

A further improvement of the present application is that the primary air volume is adjusted through the primary air adjustment door according to the actual needs of the pulverizing system.

A further improvement of the present application is that the secondary air volume is adjusted through the secondary air adjustment door according to the actual needs of boiler combustion.

The application has at least the following beneficial technical effects:

This application provides a system and method for direct combustion of oil sludge based on pulverized coal power plant boilers. Based on the existing pulverizing system, combustion system and environmental protection equipment for flue gas purification of pulverized coal power plant boilers widely distributed in China, the After the oil sludge is modified by the conditioning agent, the oil sludge is mixed with the raw coal on the coal conveyor belt, then sent to the coal bunker, and then pulverized by the coal mill and sent to the boiler furnace for combustion. During the combustion process of sludge and coal powder in the furnace, the heat utilization of sludge and the high-temperature harmless treatment of harmful substances are simultaneously completed, and the air pollutants produced by combustion are purified by the flue gas purification device at the tail flue to achieve Environmental standards for ultra-low emissions. It has the following advantages,

First: the system is simple, the construction cost is low, and there is no need to build a dedicated sludge incinerator and corresponding flue gas environmental protection equipment, saving a lot of infrastructure equipment and operation and maintenance costs;

Second: The pretreatment process of oil sludge is simple, only need to add a conditioner designed for favorable characteristics, and stir and mix in the mixer to complete the pretreatment;

Third: The pulverization, transportation and combustion of oil sludge can all be completed by using the existing pulverizing system, and there are few new equipment added to the system;

Fourth: The thermal efficiency of oil sludge utilization is high, the temperature in the boiler is high, the combustion organization is advanced, the combustion efficiency can reach more than 98%, and cogeneration of heat and power can also be used. The thermal efficiency of the system is much higher than that of special oil sludge incinerators;

Fifth: The boiler incineration temperature is high, the temperature inside the boiler can usually be as high as 1600°C, and the toxic and harmful substances in the sludge can be completely harmless treated;

Sixth: The flue gas emission control has high environmental protection standards. The flue gas purification equipment of the power plant is advanced. Pollutants such as NOx, dust and SOx produced by sludge incineration can be treated by the existing environmental protection equipment of the power plant to meet the ultra-low emission standard and meet the Relevant requirements of environmental regulations.

Description of drawings

Fig. 1 is a flow chart of a method for incinerating oil sludge using a pulverized coal power plant boiler.

Figure 2 is a structural block diagram of a system for incinerating oil sludge using a pulverized coal power plant boiler.

Figure 3 is a schematic diagram of by-products of an oil well.

Figure 4 is a schematic diagram of the appearance of a by-product of an oil well after quenching and tempering.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and embodiments.

As shown in Figure 1, this application makes full use of the system and equipment characteristics of the current coal-based power plant pulverized coal boiler, and modifies the sludge by adding a conditioner to the sludge to reduce the fluidity and volatility of the sludge. The modification process mainly It is carried out in a spiral agitator, and the oil sludge that has been tempered and modified is sent to the raw coal conveyor belt, sent to the coal bunker, and then pulverized and ground, and then burned in the furnace through the organization of the combustion system, and the flue gas passes through the environmental protection of the boiler system The device is purified to meet the emission standard of ultra-low emission. The application has a simple system structure and does not need to build a new oil sludge incinerator, oil sludge pre-treatment equipment and flue gas purification equipment, saving a lot of construction costs and equipment operation and maintenance costs. At the same time, because the pulverized coal power plant boiler has the advantages of large capacity, high combustion temperature, high boiler combustion and thermal efficiency, and good flue gas purification performance of the boiler flue gas purification equipment, the oil sludge can be treated more thoroughly and harmlessly, and can be fully Utilize the thermal resources of oil sludge, and give full play to the comprehensive effect of harmless disposal of oil sludge and synergistic power generation in the process of co-combustion of oil sludge and coal. On the one hand, the application can reduce the cost of oil sludge incineration and disposal, on the other hand, it can also realize the improvement of comprehensive benefits of pulverized coal power plant boiler oil sludge incineration and collaborative power generation, and enhance the comprehensive competitiveness of power generation enterprises.

Example:

As shown in Figure 3, the by-product sludge of an oil production well is composed of 60% oil, 8% water, 7% solid combustibles, and about 25% of other non-combustible substances such as ash, and the calorific value is as high as 33MJ/ kg. Due to the high oil content of this sludge, it has the characteristics of high calorific value. However, due to its large molecular weight of oil, the viscosity of the oil on the whole is high, and transportation is difficult and poses a greater safety risk. On the other hand, moisture and non-combustible substances also contain certain toxic and harmful substances, which need to be harmlessly treated at high temperatures. Using the method of the present application, the following steps can be adopted to carry out incineration, so as to realize the comprehensive utilization of the calorific value of the oil sludge and the harmless treatment of harmful substances.

First, as mentioned above, the main physical and chemical indicators of the oil sludge are analyzed, and it is determined that the oil sludge can be sent to the high-temperature combustion pulverized coal boiler of the power plant for comprehensive utilization and harmless treatment through the method of this aspect;

Next, according to the main indicators such as the composition of the oil sludge with 60% oil and 8% water, the temperature determined by the thermogravimetric analysis experiment compared with a large amount of volatilization analysis is controlled at about 300 ° C, and the composition of the preparation agent is determined to be about quicklime 45%, fly ash is 40%, kaolin is 15%, and the mass ratio of conditioning agent and oil sludge is 1:2. The water content of the oil sludge after conditioning is about 3%, that in the sludge is about 35%, the mass proportion of non-combustible minerals such as ash is increased to 47%, and the calorific value is about 20MJ/kg. The appearance diagram of the oil sludge after conditioning is as follows As shown in Figure 4, it shows that the physical properties and calorific value of the modified oil sludge are also close to those of ordinary raw coal, which is suitable for transportation and combustion in the coal transportation system of power plants.

Further, on the basis of laboratory research to determine the formula of the preparation and the mass ratio of the preparation and the sludge, the sludge is transported to the feed port of the mixer of the sludge and coal in a power plant through a special tank truck, etc., and Control the oil sludge and conditioning agent to be fed at a ratio of 2:1, and then the mixture of oil sludge and conditioning agent is further mixed and transported in the spiral agitator to realize the conditioning process of oil sludge.

Further, the rotation speed of the spiral agitator can be controlled, and the quality of the tempered oil sludge transported to the coal conveying belt through the spiral agitator can be controlled within about 1:9 of the mass ratio of the oil sludge and the coal conveyed on the coal conveying substitute. , the raw coal and modified oil sludge are sent to the raw coal bunker through the coal conveyor belt for mixing, and then the raw coal is mixed with modified oil sludge in the pulverization process of the coal mill to achieve secondary mixing.

Furthermore, the mixture of oil sludge and coal is sent into the boiler for combustion through the original powder conveying and combustion system of the boiler. The temperature in the pulverized coal boiler of the power station is usually as high as 1300-1600 °C, and the high-temperature incineration time of oil sludge and other particles in the furnace is about 2 -3 seconds, organic pollutants such as dioxins and heavy metals that are easily produced during the sludge combustion process will generate dust and flue gas after being incinerated under long-term high-temperature conditions in the boiler. Purification treatment is carried out, and the emission reaches the ultra-low emission standard of current thermal power plants.

During the combustion process of the whole oil sludge in the boiler of the power plant, the feeding system of the oil sludge and the preparation agent can use mature products such as conventional grab machines and elevators, and add related equipment such as mixers and spiral agitators of this application. The modified tempered oil sludge can be mixed with raw coal, and the comprehensive utilization of heat and ultra-low emission of pollutants can be realized through the existing pulverization, combustion and exhaust gas purification devices of the boiler. The system is simple, the construction cost is low, and it also has the advantages of The advantages of high efficiency and low pollution.

As shown in Figure 2, a system for incinerating oil sludge using a pulverized coal boiler in a power station provided by the present application includes: a boiler 1, an air preheater 2, a blower 3, a primary fan 4, a flue gas purification device 5, a chimney 6, two Secondary air adjustment door 7, primary air adjustment door 8, coal mill 9, separator 10, combustion system 11, coal bunker 12, coal conveyor belt 13, spiral agitator 14 and mixer feed port 15. Among them, the heat generated by the combustion of fuel in the boiler 1 passes through the heat exchange surface, and the secondary air and the primary air sent by the blower 3 and the primary fan 4 are heated by the air preheater 2, and the heated secondary air passes through the boiler. The organization of the combustion system 11 supplements the amount of oxygen for the combustion of the fuel in the furnace, and the size of the secondary air volume can be adjusted through 7 according to the actual needs of the boiler combustion; the high-pressure head hot primary air sent by the primary fan 4 is sent through the pipeline The coal mill 9 is used to dry and convey the mixture of raw coal and oil sludge in the coal mill, and its primary air volume can be adjusted through the primary air adjustment door 8 according to the actual needs of the pulverizing system.

Sludge and conditioning agent are respectively added to the feed port 15 of the mixer at the entrance of the spiral agitator 14, and then the sludge and conditioning agent are stirred in the spiral agitator 14 and mixed evenly and tempered well. The oil sludge is transported to the coal conveyor belt 13 for blending; the mixture of coal and sludge is sent to the coal bunker 12 through the coal conveyor belt 13, and the mixture of raw coal and coal slime in the coal bunker 12 is transported to the coal mill 9 through the coal drop pipe In the process, after being milled and dried, it enters the pulverized coal separator 10 carried by the primary air, and the pulverized coal separator 10 transports the pulverized coal and oil sludge powder with a particle size qualified to the combustion system 11 through the pulverized feeding pipeline. Under the organization of the system 11, it is fed into the boiler 1 for combustion; the dust, NOx and SOx and other pollutants produced by the combustion are removed from the air pollutants by the dust removal, denitrification and desulfurization devices included in the flue gas purification device 5 arranged on the tail flue. purification.

Although the present application has been described in detail with general descriptions and specific implementations above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present application. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present application all belong to the protection scope of the present application.

Claims

Utilize the method for incinerating oil sludge in power plant pulverized coal boiler, it is characterized in that, comprises the following steps:

Step 1, according to the analysis of the characteristics of the sludge, configure the sludge conditioner, and use the configured conditioner to modify the sludge with strong volatility and high water content;

Step 2, feed the oil sludge and the prepared conditioning agent into the mixer respectively, fully stir them evenly in the mixer, use the conditioning agent to modify the oil sludge, reduce the physical properties and volatility of the liquid flow of the oil sludge, and make it Similar solid properties to raw coal;

Step 3. Send the oil sludge after conditioning to the raw coal conveyor belt, and blend it with the raw coal on the coal conveyor belt according to the set ratio. The mass ratio of the blend is determined by the best ratio obtained from the blending test. ;

Step 4. The mixed oil sludge and raw coal are sent to the existing pulverization system for pulverization, and then sent to the furnace of the pulverized coal power plant boiler through the powder feeding system for high-temperature incineration. The incineration process is a mixed combustion process of coal powder and oil sludge powder The temperature is controlled in the range of 1300-1600 ℃ to ensure the harmless treatment of harmful substances in the oil sludge, and the control of the mixed combustion process is adjusted in conjunction with the optimization control of the entire boiler combustion;

Step 5, the dust, NOx and SOx pollutants produced by the combustion of raw coal and oil sludge in the boiler are purified through the denitrification, dust removal and desulfurization devices arranged in the flue at the tail of the boiler.
The method for incinerating oil sludge using a pulverized coal boiler in a power station according to claim 1, wherein in step 1, the formula of the conditioner is based on the moisture and volatile content of the oil sludge, using quicklime, fly ash and kaolin according to The proportion of the configuration is mainly quicklime, accounting for 50-60%, fly ash accounting for 20-40%, kaolin and other minerals accounting for 10-20%, the final proportion of each component is determined by the composition of oil sludge It is determined by the characteristics, and determined by comparing the experimental effects of thermogravimetric analysis on the modification of oil sludge by formulas with different proportions of components in the early stage.
According to claim 1, the method for incinerating oil sludge using a pulverized coal boiler in a power station is characterized in that, in step 2, the oil sludge is modified by using a conditioner, and a custom-made modulating agent is added according to favorable physical and chemical characteristic indicators. The fluidity and volatile characteristics of the oil sludge are improved, specifically including that after adding the conditioner, the mud state with a high moisture content that is not suitable for storage is transformed into a solid state similar to coal with a moisture content of less than 20%, so that it is easy to store and transport. Another On the other hand, those volatile and flammable components are also adsorbed by the porous modulator in the modulator, and the volatile performance is greatly reduced, and the mass ratio of the modulator is 20-30%.
According to claim 1, the method for incinerating oil sludge using a pulverized coal boiler in a power station is characterized in that in step 3, the oil sludge after quenching and tempering is mixed with raw coal on the coal conveyor belt according to the set ratio, and the coal is transported The proportion of oil sludge that can be blended on the belt does not exceed 20%.
A system for incinerating oil sludge using a pulverized coal boiler in a power station is characterized in that it includes a boiler (1), an air preheater (2), a blower (3), a primary fan (4), a flue gas purification device (5), and a coal pulverizer (9), separator (10), combustion system (11), coal bunker (12), coal conveyor belt (13), spiral agitator (14) and mixer inlet (15);

Among them, the heat generated by the combustion of fuel in the boiler (1) is heated by the air preheater (2) to the secondary air and primary air sent by the blower (3) and the primary blower (4) after heat exchange on the heat exchange surface. The heated secondary air passes through the organization of the boiler combustion system (11) to supplement the amount of oxygen for the combustion of fuel in the furnace; the high-pressure hot primary air sent by the primary fan (4) is sent to the coal mill (9) through the pipeline , drying and transporting the raw coal and oil sludge mixture in the coal mill (9);

Sludge and conditioning agent are respectively added to the feed inlet (15) of the mixer at the inlet of the spiral agitator (14), and then the sludge and conditioning agent are stirred in the spiral agitator (14) and mixed evenly and tempered After that, the oil sludge that has been tempered is transported to the coal conveyor belt (13) for blending; the mixture of coal and oil sludge is sent into the coal bunker (12) by the coal conveyor belt (13), and the raw coal and the The mixture of coal slime is transported to the coal mill (9) through the coal falling pipe, and after being ground and dried, it enters the pulverized coal separator (10) under the carrying of the primary air, and the pulverized coal separator (10) separates the particle size Qualified pulverized coal and oil sludge powder are delivered to the combustion system (11) through the powder delivery pipeline, and are sent into the boiler (1) for combustion under the organization of the combustion system (11); the dust, NOx and SOx pollutants produced by combustion, Air pollutants are purified through the dust removal, denitrification and desulfurization devices included in the flue gas purification device (5) arranged on the tail flue.
According to claim 5, the system for incinerating oil sludge by using pulverized coal boiler of power station is characterized in that the flue gas after the purification of air pollutants is discharged through the chimney (6).
According to claim 5, the system for incinerating oil sludge by using the pulverized coal boiler of the power station is characterized in that the primary air volume is adjusted through the primary air adjustment door (8) according to the actual needs of the pulverizing system.
According to claim 5, the system for incinerating sludge by using pulverized coal boiler of power station is characterized in that the size of the secondary air volume is adjusted through the secondary air adjustment door (7) according to the actual needs of boiler combustion.