WO2021244033A1 - Integrated incineration boiler system for efficient disposal of high-calorific-value waste - Google Patents

Abstract

Disclosed is an integrated incineration boiler system for efficient disposal of high-calorific-value waste, the system comprising a fire grate frame (1), wherein a water-cooled furnace (2) is provided on the fire grate frame (1); the water-cooled furnace (2) is internally provided with a fire grate (3) mounted on the fire grate frame (1); the upper end of the water-cooled furnace (2) is provided with a fume outlet (1.1), the front end thereof is provided with a waste inlet (1.2), and the rear end thereof is provided with a residue outlet (1.3); and the fume outlet (1.1) of the water-cooled furnace (2) is connected to a flue group (4). The water-cooled furnace (2) is provided on the fire grate frame (1) for disposal of high-calorific-value household waste, and the heat efficiency is high.

Description

An incineration boiler integrated system for efficiently processing high-calorific value garbage Technical field

The invention relates to the technical field of garbage incineration equipment, in particular to an incineration boiler integrated system for efficiently processing high-calorific value garbage.

Background technique

With the development of economy, the continuous improvement of people’s living standards, and the increasing awareness of waste classification, more and more regions have a rapid increase in the calorific value of garbage, especially in some developed regions and countries, which leads to the original low calorific value and high ash content. The high-moisture incineration boiler system is difficult to operate economically and stably, such as severe coking and corrosion on the heating surface, frequent tube bursts, etc.

Moreover, with the changes in garbage subsidy policies in different regions and the high requirements for environmental protection, the investment cost of the project has increased. Improving the overall efficiency of incineration boilers has become a problem.

Existing incinerators are mainly suitable for incineration of wastes with low calorific value and high moisture content. As shown in Figure 8, the angle of the lower part of the front arch of the incinerator is 25°, and the angle between the upper part of the rear arch and the horizontal line is 65°. The angle between the middle part of the arch and the horizontal line is 39°. The structurally depressing the front arch enhances the flue gas radiation and convection heat exchange so that the garbage is fully dried. The flue gas outlet of the incinerator faces the front half of the combustion section and enters the high-temperature flue gas of the flue group. The coverage area is small, and the back arch angle is small and short, so that when the waste has a low calorific value, it can save heat and avoid the high temperature flue gas energy from moving backward. However, as the calorific value of the waste increases, the furnace angle is now small and the space is limited. The release of high calorific value heat must be changed, and the key to changing the furnace type is the angle of the front and rear arches.

In addition, the angle between the drying section grate, the burning section grate and the burnout section grate of the existing incinerator and the horizontal line is 26°, 24° or 0°. When the design is 26° or 24°, the angle is too large to cause garbage The residence time in the furnace is short, and when the angle is designed to be 0°, the garbage rolls unevenly, and the garbage cannot fall freely, there are problems such as incomplete combustion and high mechanical incomplete combustion loss. The slag heat reduction rate of the three angle designs is about 95%.

Summary of the invention

The purpose of the present invention is to provide an incineration boiler integrated system for efficiently processing high-calorific value garbage, which is used in the waste heat value range of 9500-12500 kJ/kg and has high requirements on the efficiency of the incineration boiler.

The technical solution to achieve the above objective is: an integrated system of incineration boiler for efficiently processing high-calorific value garbage, which is characterized by including a grate frame on which a water-cooled furnace is arranged, and the water-cooled furnace is installed on the grate frame. For the upper grate, the upper end of the water-cooled furnace is provided with a flue gas outlet, the front end is provided with a garbage inlet, and the rear end is provided with a slag outlet, and the flue gas outlet of the water-cooled furnace is connected with a flue group.

The beneficial effects of the present invention:

The water-cooled furnace on the grate frame can process high-calorific value domestic waste, which not only provides a solution for the current high-calorific value waste treatment, but also maximizes the use of waste heat with high thermal efficiency.

Further, the water-cooled hearth includes a front arch, a back arch, and furnace walls on both sides. The inner walls of the front arch, the back arch, and the furnace walls on both sides are provided with first water-cooled pipe walls. The tube wall is covered with a nickel-chromium alloy coating, and the first water-cooled tube walls of the furnace walls on both sides are covered with a second castable coating.

Because the front and rear arches are positively scoured by the flue gas and are severely worn or corroded, the nickel-chromium alloy coating is used, which has good wear resistance and corrosion resistance. The side wall is vertical, and the flue gas follows the side wall, so it is directly Use castables.

Further, the front arch includes an upper vertical section and a lower inclined section. The lower inclined section of the front arch is inclined forward and downward, and forms an angle of 30° to 35° with the horizontal; the rear arch includes an upper vertical section and a middle inclined section. And the lower inclined section, the middle inclined section and the lower inclined section of the rear arch are inclined backward and downward, and the angle between the middle inclined section of the rear arch and the horizontal line is 63°～66°, and the lower inclined section of the rear arch is clamped between the horizontal line and the horizontal line. The angle is 20°～25°.

The invention optimizes the design according to the characteristics of high calorific value garbage and low moisture. The angle between the lower inclined section of the front arch and the horizontal line is designed to be 30°～35°, so that the front arch is raised so that garbage with high calorific value does not need to be carried out for too long. Moisture can be removed by drying. The upper part of the back arch is a vertical section, and the angle between the inclined section of the middle part of the back arch and the horizontal line is 63°～66°. This large-angle design makes the high-calorific value garbage have enough space and time for energy release and sufficient heat Absorbed and converted by the water-cooled furnace. The angle between the inclined section of the lower back arch and the horizontal line is 20°～25°. The design of such a small angle and short back arch can well flush the smoke and combustion particles from the end of the back arch to the garbage surface of the burning section. , Further strengthen the radiant heat and convection heat exchange, greatly reduce the incomplete combustion loss of garbage machinery.

The invention designs a reasonable water-cooled furnace shape, thereby obtaining a suitable furnace volume heat load, avoiding too much furnace heat load and high furnace flame fullness, resulting in excessive furnace temperature, refractory material damage, and incomplete combustion of flue gas residence time, etc. At the same time, it can also avoid the problems that the furnace volume is too small and the heat load is too large. The furnace flame is too full and the furnace temperature is low, the combustion is unstable, and the slag heat loss rate is high.

Further, the grate includes a drying section grate, a combustion section grate, and a burn-out section grate that are arranged obliquely in sequence, and the flue gas outlet of the incinerator is directly opposite to the drying section grate and the combustion section grate. The angles between the grate in the drying section, the grate in the combustion section and the grate in the burnout section and the horizontal line are all 15°-18°.

The flue gas outlet of the incinerator of the present invention faces between the grate of the drying section and the grate of the combustion section, so that the coverage area is large, and a lot of high-energy flue gas enters the flue group, which can make full use of the radiant heat and convection heat of the flue gas. High heat utilization efficiency.

The design of the present invention considers the repose angle of garbage stacking at 45°, and the angle between the grate of the drying section, the grate of the burning section and the grate of the burned-out section and the horizontal line is 15-18°, which can prevent the angle from being too large, and the garbage will fall down and stay quickly. When the time is short, it can avoid the problem of too small angle and incomplete combustion. The structure design can make the slag heat reduction rate reach 97-98.5%.

Further, the upper vertical sections of the front arch and the rear arch are respectively provided with two rows of secondary air nozzles, the secondary air nozzles are all inclined inwardly, and the air outlet is located at the low end, and the upper part of the water-cooled furnace is also equipped with auxiliary burner.

Compared with the single-layer arrangement of the two rows of secondary air nozzles in the prior art, the air is evenly discharged and has a good disturbance effect on the flue gas. This makes the harmful pollutants that are not completely burned in the flue gas such as CO fully contacted with the air. Reaction, thereby reducing the concentration of CO, can reduce the secondary pollutants to a greater extent.

Further, the flue group includes a first vertical flue connected to the flue gas outlet of the water-cooled furnace, the outlet end of the first vertical flue is connected to the second vertical flue, and the outlet end of the second vertical flue A third vertical flue arranged vertically is connected, the outlet end of the third vertical flue is connected with a horizontal flue, the outlet end of the horizontal flue is connected with a tail flue, and the tail flue is arranged in the vertical direction Multiple sets of economizers connected in series.

Further, the inner walls of the first vertical flue, the second vertical flue, and the third vertical flue are respectively provided with second water-cooled pipe walls, and the first vertical flue is close to the first vertical flue on the side of the smoke outlet. The wall of the second water-cooled tube is covered with a first induction remelting layer, and the walls of the second water-cooled tube in other areas of the first vertical flue except for the first induction remelting layer are covered with a third castable coating. The walls of the second water-cooled pipes in the two vertical flues are covered with a second induction remelting layer.

By setting multiple flues and reasonably setting the area ratio of the castable covering the second water-cooled pipe wall in the first vertical flue to the induction remelting area, it is ensured that the temperature of the flue gas at the outlet of the first vertical flue stays above 850℃ Time ≥ 2s, to ensure that the flue gas temperature at the outlet of the tail flue is 190～220℃. It can not only maximize the use of the waste heat of the flue gas at the outlet of the water-cooled furnace, but also make the flue gas have a reasonable temperature field distribution to ensure the life of the boiler.

The first induction remelting layer is provided on the second water-cooled pipe wall of the first vertical flue near the side of the smoke outlet. Compared with the nickel-chromium alloy layer used in the prior art, the cost is low, and it is installed on the project site. The induction remelting operation is convenient and the maintenance cost is low.

The second water-cooled pipe wall in the first vertical flue adopts the third castable coating except for the side close to the smoke outlet. Compared with the nickel-chromium alloy layer in the prior art, it can ensure Under various working conditions, the flue gas temperature is above 950℃ and the residence time is more than 2s, which meets the technical requirements of different countries for domestic waste incineration monitoring network transmission technology.

Moreover, compared with the prior art that the wall of the water-cooled pipe in the second vertical flue is in direct contact with the flue gas, the second water-cooled pipe wall of the second vertical flue in the present invention is covered with an induction remelting layer to protect the water-cooled The function of the pipe wall can greatly reduce the corrosion and coking problem at the exit corner of the second vertical flue.

Further, the horizontal flue is provided with a high-temperature superheater, a high-temperature reheater, a medium-temperature superheater, a low-temperature reheater, and a low-temperature superheater, which are arranged in sequence along the flue gas conveying direction and used to provide steam to the steam turbine. After the coal heaters are connected in series, they are connected to the inlet end of the low-temperature superheater through a steam drum. The outlet end of the low-temperature superheater is connected to the medium-temperature superheater, the high-temperature superheater, and then the high-pressure cylinder of the steam turbine. The output end of the high-pressure cylinder of the steam turbine is connected to the low-temperature reheat in turn Connect the low-pressure cylinder of the steam turbine after the high-temperature reheater.

The setting of high temperature superheater, high temperature reheater, medium temperature superheater, low temperature reheater, and low temperature superheater can maximize the use of flue gas waste heat, which can ensure that low temperature superheated steam is heated to high temperature superheated steam and sent to the steam turbine for work. Electric energy can also send the spent steam after work to the reheater for secondary reheating and then to the steam turbine for power generation, which improves the cycle thermal efficiency of the unit.

Further, the high-temperature superheater and the high-temperature reheater are both made of TP310S stainless steel, and the inner wall of the inlet end of the high-temperature superheater is provided with a wear-resistant layer.

The outlet of the low-temperature reheater is connected to the high-temperature reheater, and the output steam of the low-temperature reheater is used to adjust the steam temperature at the outlet of the high-temperature reheater to avoid excessively high steam temperature and reduce the allowable stress of metal to affect the safety of the unit. At the same time, avoid excessively low steam temperature Affect the cycle thermal efficiency of the unit.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the present invention;

Figure 2 is a partial top view of the flue group;

Figure 3 is a cross-sectional view along the line A-A in Figure 2;

Figure 4 is a cross-sectional view taken along line B-B in Figure 2;

Figure 5 is a schematic diagram of the structure of the water-cooled furnace;

Figure 6 is a cross-sectional view along the line A-A in Figure 5;

Figure 7 is a schematic diagram of the connection relationship between the high temperature superheater, the high temperature reheater, the medium temperature superheater, the low temperature reheater, the low temperature superheater and the steam turbine;

Figure 8 is a structural view of an existing furnace.

detailed description

As shown in Figures 1-7, the present invention includes a grate frame 1, a water-cooled hearth 2 is provided on the grate frame 1, and a grate 3 installed on the grate frame 1 is provided in the water-cooled hearth 2, and the grate 3 includes successively Inclined drying section grate 3.1, combustion section grate 3.2 and burnout section grate 3.3, the angle between the drying section grate 3.1, combustion section grate 3.2 and burnout section grate 3.3 and the horizontal line are all a, a=15°-18°, more preferably, a=17.6°.

The upper end of the water-cooled furnace 2 is provided with a flue gas outlet 1.1, the front end is provided with a garbage inlet 1.2, and the rear end is provided with a slag outlet 1.3. The flue gas outlet of the water-cooled furnace 1 is connected with a flue group 4, and the water-cooled furnace 2 includes a front arch 2.1 The inner walls of the rear arch 2.2 and the furnace walls 2.3 on both sides, the front arch 2.1, the rear arch 2.2 and the inner walls of the furnace walls 2.3 on both sides are provided with a first water-cooled pipe wall 2.7, and the first water-cooled pipe wall 2.7 of the front arch 2.1 and the rear arch 2.2 It is covered with a nickel-chromium alloy coating (not shown in the figure), and the first water-cooled pipe wall 2.7 of the furnace wall 2.3 on both sides is covered with a second castable coating 2.8.

The front arch 2.1 includes an upper vertical section 2.11 and a lower inclined section 2.12. The lower inclined section 2.12 of the front arch 2.1 is arranged obliquely forward and downward, and the angle with the horizontal line is b, b=30°～35°, further preferably, b =33°; The rear arch 2.2 includes the upper vertical section 2.21, the middle inclined section 2.22 and the lower inclined section 2.23. The middle inclined section 2.22 and the lower inclined section 2.23 of the rear arch 2.2 are both inclined backward and downward, and the middle inclined section of the rear arch 2.2 The angle between 2.22 and the horizontal line is c, c=63°～66°, more preferably, c=65°, the angle between the lower inclined section of the back arch and the horizontal line is d, d=20°～25°, and it is more preferable地，d=22°.

The upper vertical section 2.11 of the front arch 2.1 and the upper vertical section 2.21 of the rear arch 2.2 are respectively provided with two rows of secondary air nozzles 5. Auxiliary burner 6 is also installed on the upper part.

The flue group 4 includes a first vertical flue 4.1 connected to the water-cooled furnace flue gas outlet 1.1, the outlet end of the first vertical flue 4.1 is connected to the second vertical flue 4.2, and the outlet of the second vertical flue 4.2 The end is connected with a vertically arranged third vertical flue 4.3, the outlet end of the third vertical flue 4.3 is connected with a horizontal flue 4.4, and the outlet end of the horizontal flue 4.4 is connected with two tail flues 4.5, two The tail flue 4.5 is provided with multiple sets of economizers 7 arranged in the vertical direction, and the multiple sets of economizers 7 in the two tail flues 4.5 are connected in series.

The peripheral side walls of the first vertical flue 4.1, the second vertical flue 4.2, and the third vertical flue 4.3 are respectively provided with second water-cooled pipe walls 8, and the first vertical flue 4.1 is close to the first smoke outlet. The second water-cooled tube wall 8 on the side is covered with a first induction remelting layer 9 (that is, the shaded area A in Figure 2), and the first vertical flue 4.1 covers the first induction remelting layer 9 in other areas The two water-cooled tube walls 8 are both covered with a third castable coating layer 20, and the second water-cooled tube walls 8 in the second vertical flue 4.2 are covered with a second induction remelting layer 21.

The area ratio of the first induction remelted layer 9 and the third castable layer 20 covered on the second water-cooled tube wall 8 in the first vertical flue 4.1 is 1:4.3, and the first induction remelted layer 9 and the second induction The remelted layer 21 is made of nickel-based alloy with a thickness of 0.8mm, nickel content ≥70%, chromium content ≥3%, and hardness ≥HRC40.

The third pouring coating layer 20 covered on the second water-cooled pipe wall in the first vertical flue 4.1 and the first induction remelting layer 9 adopts the form of overlap, that is, the first induction remelting layer 9 is poured toward the third The extension of the paint layer 20 is not less than 80 mm.

The horizontal flue 4.4 is provided with a high-temperature superheater 10, a high-temperature reheater 11, a medium-temperature superheater 12, a low-temperature reheater 13, and a low-temperature superheater 14 for supplying steam to the steam turbine in sequence along the flue gas conveying direction, and two tail flues The economizers 7 in 4.5 are connected in series with each other through the steam drum 16 to connect the inlet end of the low-temperature superheater 14, and the outlet end of the low-temperature superheater 14 is connected to the low-temperature superheater 14, the medium-temperature superheater 12, and the high-temperature superheater 10 in turn, and then connected to the steam turbine The output ends of the high-pressure cylinder 17 of the steam turbine 17 and the high-pressure cylinder of the steam turbine 17 are connected in series with the low-temperature reheater 13 and the high-temperature reheater 11, and then connected to the low-pressure cylinder of the steam turbine 17.

The saturated steam from the steam drum 16 enters the low-temperature superheater 14 to become low-temperature superheated steam. The low-temperature superheated steam then enters the medium-temperature superheater 12. After absorbing heat in the medium-temperature superheater 12, it becomes medium-temperature superheated steam, and the medium-temperature superheated steam then enters the high-temperature superheated steam. The superheater 10 absorbs heat in the high-temperature superheater 10 and turns it into high-temperature superheated steam, which is sent to the high-pressure cylinder of the steam turbine 17 to perform work. The steam completed in the high-pressure cylinder of the steam turbine 17 enters the low-temperature reheater 13, and is heated in the low-temperature reheater 13 to become low-temperature reheated steam. The low-temperature reheated steam then enters the high-temperature reheater 11 and is reheated at high temperature. The steam in the device 11 is heated into high-temperature reheated steam and then sent to the low-pressure cylinder of the steam turbine 17 to perform work again for output. This design method can maximize the use of flue gas waste heat and improve the thermal efficiency of the unit.

The outlet of the low-temperature reheater 13 is connected to the outlet of the high-temperature reheater 11 at the same time. The low-temperature reheat steam is used to adjust the outlet steam of the high-temperature reheater to avoid excessively high steam temperature and reduce the allowable stress of the metal to affect the safety of the unit. At the same time, avoid excessively low steam temperature Affect the cycle thermal efficiency of the unit.

Both the high-temperature superheater 10 and the high-temperature reheater 11 are made of TP310S stainless steel, and the inner wall of the inlet end of the high-temperature superheater 10 is provided with a wear-resistant layer. Compared with the 12Cr1MoVG used in the prior art, the TP310S material has strong corrosion resistance and wear resistance. Extend the service life of the superheater.

The working principle of the present invention:

The 1050°C flue gas at the outlet of the water-cooled furnace 2 passes through the first vertical flue 4.1, and the flue gas temperature decreases by about 150°C. After passing through the second vertical flue 4.2, the temperature decreases by about 180°C and passes through the third vertical flue 4.3. After passing through the high temperature superheater 10, the temperature drops by about 87°C, the high temperature reheater 11 temperature drops by about 30°C, the medium temperature superheater 12 temperature drops by about 55°C, and the low temperature reheater 13 temperature drops by about 55°C. The temperature of the low-temperature superheater 14 is reduced by about 70°C, and after the economizer 7, the temperature is reduced by about 170°C. At this time, the flue gas temperature is 190°C and discharged into the subsequent flue gas treatment system.

This design enables the flue gas at the outlet of the water-cooled furnace 2 to be fully absorbed from 1050°C through the flue group 4 to 190°C and then discharged into the subsequent flue gas treatment system. Moreover, the flue gas temperature at the inlet of the high-temperature superheater is less than 650°C, which avoids the strong corrosion of the flue group 4 caused by acid gases such as HCL and SOx in the high-temperature flue gas.

Claims (10)

1. An integrated incineration boiler system for efficiently processing high calorific value garbage, which is characterized in that it includes a grate frame, a water-cooled furnace is arranged on the grate frame, and a grate installed on the grate frame is arranged in the water-cooled furnace. The upper end is provided with a flue gas outlet, the front end is provided with a garbage inlet, the rear end is provided with a slag outlet, and the flue gas outlet of the water-cooled furnace is connected with a flue group.
2. The integrated incineration boiler system for efficiently processing high-calorific value waste according to claim 1, characterized in that: the water-cooled furnace includes a front arch, a back arch, and both sides of the furnace walls, a front arch, a back arch, and both sides of the furnace The inner wall of the wall is provided with a first water-cooled pipe wall, the first water-cooled pipe walls of the front arch and the rear arch are covered with a nickel-chromium alloy coating, and the first water-cooled pipe walls of the furnace walls on both sides are covered with a second water-cooled pipe wall. Castable coating.
3. The integrated system of an incineration boiler for efficiently processing high-calorie garbage according to claim 2, characterized in that: the front arch includes an upper vertical section and a lower inclined section, and the lower inclined section of the front arch is inclined forward and downward, It is at an angle of 30°～35° with the horizontal line; the rear arch includes the upper vertical section, the middle inclined section and the lower inclined section. The middle and lower inclined sections of the rear arch are inclined backward and downward, and the middle inclined section of the rear arch The angle with the horizontal line is 63°～66°, and the angle between the lower inclined section of the back arch and the horizontal line is 20°～25°.
4. The incineration boiler integrated system for efficiently processing high-calorific value garbage according to claim 1, wherein the grate includes a drying section grate, a combustion section grate and a burnout section which are arranged in an inclined manner. Grate, the flue gas outlet of the incinerator is directly between the drying section grate and the combustion section grate, the angle between the drying section grate, the combustion section grate and the burnout section grate and the horizontal line is 15°～18 °.
5. The incineration boiler integrated system for efficiently processing high-calorific value garbage according to claim 2, characterized in that: the upper vertical section of the front arch and the rear arch are respectively provided with two rows of secondary air nozzles, and the secondary air nozzles are both It is arranged inclined inward and the air outlet is located at the low end, and an auxiliary burner is also installed on the upper part of the water-cooled furnace.
6. The incineration boiler integrated system for efficiently processing high-calorific value garbage according to claim 1, wherein the flue group includes a first vertical flue connected to the flue gas outlet of the water-cooled furnace, and the first vertical flue The outlet end of the flue is connected to the second vertical flue, the outlet end of the second vertical flue is connected to a third vertical flue arranged vertically, and the outlet end of the third vertical flue is connected to a horizontal flue, The outlet end of the horizontal flue is connected with a tail flue, and a plurality of groups of economizers connected in series are arranged in the vertical direction in the tail flue.
7. The integrated system of an incineration boiler for efficiently processing high-calorific value garbage according to claim 1, characterized in that: the first vertical flue, the second vertical flue, and the third vertical flue are respectively on the surrounding inner walls A second water-cooled pipe wall is provided, and the second water-cooled pipe wall on the side of the first vertical flue near the smoke outlet is covered with a first induction remelting layer, and the first vertical flue is provided with a first induction remelting layer The walls of the second water-cooled pipes in other areas are covered with a third castable coating, and the walls of the second water-cooled pipes in the second vertical flue are all covered with a second induction remelting layer.
8. The incineration boiler integrated system for efficiently processing high-calorific value garbage according to claim 6, characterized in that: the horizontal flue is provided with high-temperature superheaters and high-temperature superheaters arranged in sequence along the flue gas conveying direction and used to provide steam to the steam turbine. Reheater, medium temperature superheater, low temperature reheater, low temperature superheater, the economizer in the tail flue is connected in series with each other and then connected to the inlet end of the low temperature superheater through the steam drum, and the outlet end of the low temperature superheater is connected to the medium temperature superheater in turn , After the high temperature superheater is connected to the high pressure cylinder of the steam turbine, the output end of the high pressure cylinder of the steam turbine is connected to the low temperature reheater, the high temperature reheater and then the low pressure cylinder of the steam turbine.
9. The incineration boiler integrated system for efficiently processing high-calorific value garbage according to claim 8, characterized in that: the high-temperature superheater and the high-temperature reheater are made of TP310S stainless steel, and the inner wall of the inlet end of the high-temperature superheater is provided with Wear-resistant layer.
10. The incineration boiler integrated system for efficiently processing high-calorific value garbage according to claim 9, wherein the outlet of the low-temperature reheater is simultaneously connected to the outlet end of the high-temperature reheater.

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