Coking plant waste heat resource comprehensive utilization system

Abstract

The utility model discloses a comprehensive utilization system for waste heat resources of a coking plant, which comprises a dry quenching waste heat boiler, a flue gas waste heat boiler, a demineralized water deaerator, a steam turbine high-pressure cylinder and a steam turbine low-pressure cylinder, and a first superheater outlet of the dry quenching waste heat boiler is communicated with a steam inlet of the steam turbine high-pressure cylinder. An exhaust port of the steam turbine high-pressure cylinder is communicated with a middle-gear steam user and / or an inlet of a second superheater of the dry quenching waste heat boiler, an outlet of the second superheater is communicated with a steam inlet of the steam turbine low-pressure cylinder, and an exhaust port of the steam turbine low-pressure cylinder is communicated with the demineralized water deaerator; the flue gas waste heat boiler is arranged on a communicating pipeline of a coke oven and a chimney, one part of fluid in a heater in the flue gas waste heat boiler flows to a low-grade steam user, and the other part of the fluid in the heater in the flue gas waste heat boiler flows to a middle-grade steam user. According to the comprehensive utilization system for the waste heat resources of the coking plant, the generating capacity is improved, waste heat is fully utilized, and energy waste is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat recovery and utilization, in particular to a comprehensive utilization system for waste heat resources in a coking plant. Background Art

[0002] Waste heat utilization has always been the key to improving energy efficiency, energy conservation and emission reduction in various industries. The waste heat utilization of coke dry quenching in the coking industry started earlier and the technology is relatively mature. While waste heat power generation is carried out, it also provides a steam source for the whole plant. With the progress of the waste heat utilization technology field in the coking industry, the waste heat potential in the coking industry has been further developed, mainly manifested as the waste heat utilization of riser pipes and flue gas.

[0003] At present, only conventional 0.6Mpa low-pressure saturated steam is produced by using waste heat, and the insufficient part of steam with other parameters is supplemented by the extraction and pressure reduction of waste heat power generation from coke dry quenching. With the maturity of the waste heat utilization technology of riser pipes and flue gas, the waste heat utilization heat sources increase, and there is even a phenomenon of excessive external supply of 0.6Mpa low-pressure saturated steam produced. In the case of no external supply object, it can only be emptied and discharged, resulting in great energy waste and environmental pollution. Content of the Utility Model

[0004] In view of this, the utility model provides a comprehensive utilization system for waste heat resources in a coking plant, which conducts gradient utilization of waste heat resources, improves the power generation amount, fully utilizes waste heat, the produced steam is self-used spontaneously, avoiding the emptying and external discharging of steam and energy waste.

[0005] To achieve the above object, the utility model provides the following technical solutions:

[0006] A comprehensive utilization system for waste heat resources in a coking plant includes a coke dry quenching waste heat boiler, a flue gas waste heat boiler, a demineralized water deaerator, a high-pressure cylinder of a steam turbine and a low-pressure cylinder of a steam turbine. The outlet of the first superheater of the coke dry quenching waste heat boiler is communicated with the steam inlet of the high-pressure cylinder of the steam turbine. The exhaust port of the high-pressure cylinder of the steam turbine is communicated with a medium-grade steam user and / or the inlet of the second superheater of the coke dry quenching waste heat boiler. The outlet of the second superheater is communicated with the steam inlet of the low-pressure cylinder of the steam turbine. The exhaust port of the low-pressure cylinder of the steam turbine is communicated with the demineralized water deaerator;

[0007] The flue gas waste heat boiler is arranged on the connecting pipeline between the coke oven and the chimney. The heater in the flue gas waste heat boiler is communicated with the demineralized water deaerator. A part of the fluid flowing through the heater in the flue gas waste heat boiler flows to a low-grade steam user, and another part flows to a medium-grade steam user.

[0008] Optionally, the flue gas waste heat boiler includes a first-stage waste heat boiler and a second-stage waste heat boiler connected through a flue gas distribution pipeline. The inlet and outlet of the flue gas distribution pipeline are both connected to the main flue gas pipeline, and the main flue gas pipeline is connected between the chimney and the coke oven.

[0009] The first-stage waste heat boiler is arranged near the inlet end of the flue gas distribution pipeline, and the second-stage waste heat boiler is arranged near the outlet end of the flue gas distribution pipeline. The fluid flowing out of the deaerator for demineralized water enters the first heater and the second heater in the second-stage waste heat boiler. The outlet of the first heater is connected to the low-grade steam user, and the outlet of the second heater is connected to the third heater in the first-stage waste heat boiler.

[0010] Optionally, the first heater is connected in a circulating loop with the low-pressure steam drum of the flue gas waste heat boiler, and the third heater is connected in a circulating loop with the medium-pressure steam drum of the flue gas waste heat boiler.

[0011] The outlet of the third heater is connected to the inlet of the riser superheater, and the outlet of the riser superheater is connected to the medium-grade steam user. The riser superheater is arranged on the coke oven.

[0012] Optionally, a first flue gas valve is arranged on the flue gas distribution pipeline at the front end of the first-stage waste heat boiler, a second flue gas valve is arranged on the flue gas distribution pipeline at the rear end of the second-stage waste heat boiler, and a third flue gas valve is arranged on the main flue gas pipeline.

[0013] A dry desulfurization device and an integrated dust removal and denitration device are arranged on the pipeline between the first-stage waste heat boiler and the second-stage waste heat boiler.

[0014] Optionally, a riser evaporator is further arranged on the coke oven. The riser evaporator and the riser steam drum form a circulation loop. The inlet of the riser steam drum is connected to the deaerator for demineralized water, and the outlet of the riser steam drum is connected to the inlet of the riser superheater.

[0015] Optionally, the outlet of the riser superheater is further connected to the heating inlet of the rich oil heater. The heating outlet of the rich oil heater is connected to the flash tank. The low-pressure steam flashed by the flash tank flows into the low-grade steam user, and the high-temperature water flashed by the flash tank flows into the low-pressure heater. The low-pressure heater is used to heat the liquid flowing into the deaerator for demineralized water.

[0016] Optionally, the deaerator for demineralized water includes a first deaerator for demineralized water and a second deaerator for demineralized water. The first deaerator for demineralized water is connected to the second-stage waste heat boiler and the riser steam drum to provide demineralized water for both of them. The second deaerator for demineralized water is connected to the superheater of the coke dry quenching waste heat boiler to provide demineralized water for it.

[0017] A secondary economizer is provided on the pipeline connecting the second demineralized water deaerator and the superheater of the coke dry quenching waste heat boiler.

[0018] Optionally, the first demineralized water deaerator and the second demineralized water deaerator are connected to the steam outlet of the low-pressure cylinder of the steam turbine, and the liquid outlet of the low-pressure cylinder of the steam turbine is connected to the liquid inlet of the second demineralized water deaerator;

[0019] A condenser and a low-pressure heater are sequentially arranged on the pipeline connecting the liquid outlet of the low-pressure cylinder of the steam turbine and the liquid inlet of the second demineralized water deaerator, and the condenser is arranged close to the low-pressure cylinder of the steam turbine.

[0020] Optionally, the low-pressure heater includes a first low-pressure heater and a second low-pressure heater, and the first low-pressure heater is arranged close to the condenser;

[0021] The heating inlet of the first low-pressure heater is connected to the steam outlet of the low-pressure cylinder of the steam turbine, and the heating outlet of the first low-pressure heater is connected to the condenser;

[0022] The heating inlet of the second low-pressure heater is connected to the high-temperature water outlet of the flash tank after flashing, and the heating outlet of the second low-pressure heater is connected to the first demineralized water deaerator.

[0023] Optionally, a back-pressure steam turbine is further included. A water pump is arranged on the liquid outlet pipeline of the demineralized water deaerator. The power input end of the water pump is connected to the power output end of the back-pressure steam turbine. The steam input port of the back-pressure steam turbine is connected to the outlet of the riser superheater, and the steam output port of the back-pressure steam turbine is connected to the low-grade steam user.

[0024] As can be seen from the above technical solution, in the comprehensive utilization system of waste heat resources in a coking plant provided by the present utility model, the high-pressure cylinder of the steam turbine converts the power of high-pressure steam into the electric power output of the generator. The medium-grade steam is discharged from the outlet of the high-pressure cylinder of the steam turbine. The medium steam is distributed as needed. Part of it flows to medium-grade steam users, and the other part flows to the second superheater for heating. The heated steam returns to the low-pressure cylinder of the steam turbine for power generation, thereby providing more power generation and being able to adjust the required amount of medium-grade steam as needed to avoid waste. The flue gas waste heat boiler produces medium-grade steam and low-grade steam respectively to meet the needs of low-grade steam users and medium-grade steam users. In the comprehensive utilization system of waste heat resources in a coking plant of the present utility model, the steam is configured in three grades, and the waste heat resources are used to improve the steam quality as much as possible and improve the power generation efficiency. The high-grade steam increases the power generation. The medium-grade steam is configured according to the shortage of the consumption of low-grade steam. The excess part of the medium-grade steam continues to generate power after being reheated by the coke dry quenching waste heat boiler. In the comprehensive utilization system of waste heat resources in a coking plant of the present utility model, high-temperature ultra-high pressure reheat parameters are adopted, and the steam turbine is arranged with a double-cylinder structure of a high-pressure cylinder and a low-pressure cylinder, which improves the power generation, fully utilizes the waste heat, and the generated steam is self-used, avoiding the discharge of steam to the outside, and avoiding energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a schematic structural diagram of the comprehensive utilization system of waste heat resources in a coking plant provided by the embodiment of the present utility model;

[0027] Figure 2 It is a schematic connection structure diagram of the steam turbine and the coke dry quenching waste heat boiler provided by the embodiment of the present utility model;

[0028] Figure 3 It is a schematic structural diagram of the positions of the high-pressure cylinder and the low-pressure cylinder of the steam turbine provided by the embodiment of the present utility model;

[0029] Figure 4 It is a schematic structural diagram of the flue gas waste heat boiler provided by the embodiment of the present utility model;

[0030] Figure 5 It is a schematic application structure diagram of the back-pressure steam turbine provided by the embodiment of the present utility model.

[0031] Wherein:

[0032] 1, coke oven; 2, dry quenching waste heat boiler; 201, first superheater outlet; 202, second superheater outlet; 203, first superheater; 204, second superheater; 3, dry quenching boiler steam drum; 4, auxiliary economizer; 5, high pressure cylinder of steam turbine; 6, low pressure cylinder of steam turbine; 601, first steam outlet; 602, second steam outlet; 603, liquid outlet; 7, generator; 8, condenser; 801, first opening; 802, second opening; 9, condensate pump; 10, first low pressure heater; 11, second low pressure heater; 12, second demineralized water deaerator; 13, back pressure steam turbine; 14, first demineralized water deaerator; 15, second water pump; 16, first water pump; 17, medium pressure steam drum of flue gas waste heat boiler; 18, first stage waste heat boiler; 19, second stage waste heat boiler; 20, low pressure steam drum of flue gas waste heat boiler; 21, dry desulfurization device; 22, integrated dust removal and denitration device; 23, induced draft fan; 24, riser superheater; 25, riser evaporator; 26, second pressure reducing valve; 27, riser steam drum; 28, rich oil heater; 29, flash tank; 30, first pressure reducing valve; 31, medium grade steam user; 32, low grade steam user; 33, forced circulation pump; 34, chimney; 35, first flue valve; 36, second flue valve; 37, third flue valve; 38, third water pump. Detailed implementation manners

[0033] The utility model discloses a comprehensive utilization system for waste heat resources in a coking plant, which utilizes waste heat resources in a gradient manner, improves power generation, makes full use of waste heat, and the generated steam is self-used, avoiding steam being discharged and wasted, and avoiding energy waste.

[0034] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present utility model.

[0035] Refer to Figures 1 to 5, the comprehensive utilization system of waste heat resources in a coking plant of the present utility model includes a coke dry quenching waste heat boiler 2, a flue gas waste heat boiler, a demineralized water deaerator, a high-pressure cylinder 5 of a steam turbine, and a low-pressure cylinder 6 of a steam turbine. The outlet 201 of the first superheater of the coke dry quenching waste heat boiler 2 is communicated with the steam inlet of the high-pressure cylinder 5 of the steam turbine. The exhaust port of the high-pressure cylinder 5 of the steam turbine is communicated with a medium-grade steam user 31 and / or the inlet of the second superheater of the coke dry quenching waste heat boiler 2. The outlet 202 of the second superheater is communicated with the steam inlet of the low-pressure cylinder 6 of the steam turbine to provide driving steam for the low-pressure cylinder 6 of the steam turbine. The exhaust port of the high-pressure cylinder 5 of the steam turbine is communicated with the demineralized water deaerator. The flue gas waste heat boiler is arranged on the connecting pipeline between the coke oven 1 and the chimney 34. The heater in the flue gas waste heat boiler is communicated with the demineralized water deaerator. A part of the fluid flowing through the heater in the flue gas waste heat boiler flows to a low-grade steam user 32, and the other part flows to the medium-grade steam user 31.

[0036] Among them, a first superheater 203 and a second superheater 204 are arranged in the coke dry quenching waste heat boiler 2. The first superheater 203 is used to heat the fluid flowing into the high-pressure cylinder 5 of the steam turbine, and the second superheater 204 is used to heat the fluid flowing into the low-pressure cylinder 6 of the steam turbine. In order to increase the pressure of the fluid entering the high-pressure cylinder 5 of the steam turbine, a plurality of first superheaters 203 are arranged in series, as Figure 2 shown. The steam outlet of the medium-grade steam user 31 is communicated with the steam inlet of the low-grade steam user 32. The high-grade steam flows into the steam inlet of the high-pressure cylinder 5 of the steam turbine. The coke dry quenching waste heat boiler 2 produces high-pressure steam, which is generally used for the steam consumption of the whole plant and power generation. The demineralized water deaerator provides the demineralized water, which is the heating medium required by the system.

[0037] The comprehensive utilization system of waste heat resources in a coking plant of the present utility model. The high-pressure cylinder 5 of the steam turbine converts the power of high-pressure steam into the electric power output of the generator 7. The medium-grade steam is discharged from the outlet of the high-pressure cylinder 5 of the steam turbine. The medium steam is distributed as needed. A part of it flows to the medium-grade steam user 31, and the other part flows to the second superheater 204 for heating. The heated steam flows back to the low-pressure cylinder 6 of the steam turbine for power generation, so as to provide more power generation capacity and can adjust the required amount of medium-grade steam as needed to avoid waste. The flue gas waste heat boiler produces medium-grade steam and low-grade steam respectively to meet the needs of the low-grade steam user 32 and the medium-grade steam user 31. In the comprehensive utilization system of waste heat resources in a coking plant of the present utility model, the steam is configured in three grades, and the waste heat resources are used to improve the steam quality as much as possible and improve the power generation efficiency. The high-grade steam increases the power generation capacity. The medium-grade steam is configured according to the usage gap of the low-grade steam. The excess part of the medium-grade steam is reheated by the coke dry quenching waste heat boiler 2 and then continues to generate electricity. In the comprehensive utilization system of waste heat resources in a coking plant of the present utility model, the high-temperature ultra-high pressure reheat parameters are adopted, and the steam turbine is provided with a double-cylinder setting of a high-pressure cylinder and a low-pressure cylinder, which improves the power generation capacity, fully utilizes the waste heat, and the generated steam is self-used, avoiding the steam from being emptied and discharged, and avoiding energy waste.

[0038] Specifically, the flue gas waste heat boiler includes a first-stage waste heat boiler 18 and a second-stage waste heat boiler 19 connected by a flue gas distribution pipeline. The inlet and outlet of the flue gas distribution pipeline are both connected to the main flue gas pipeline, and the main flue gas pipeline is connected between the chimney 34 and the coke oven 1. The flue gas distribution pipeline is connected in parallel to the main flue gas pipeline. The first-stage waste heat boiler 18 is arranged near the inlet end of the flue gas distribution pipeline, and the second-stage waste heat boiler 19 is arranged near the outlet end of the flue gas distribution pipeline. The fluid flowing out of the deaerator for feed water enters the first heater and the second heater in the second-stage waste heat boiler 19. The outlet of the first heater is connected to the low-grade steam user 32, and the outlet of the second heater is connected to the third heater in the first-stage waste heat boiler 18. The first heater is connected in a cycle to the low-pressure steam drum 20 of the flue gas waste heat boiler, and the third heater is connected in a cycle to the medium-pressure steam drum 17 of the flue gas waste heat boiler. The feed water of the low-pressure section of the boiler is pressurized and sent into the first heater (low-pressure economizer) of the second-stage waste heat boiler 19. After heat exchange, it enters the low-pressure steam drum 20 of the flue gas waste heat boiler, and then undergoes natural circulation in the second-stage waste heat boiler 19. The steam-water mixture generated after circulation is separated by the low-pressure steam drum 20 of the flue gas waste heat boiler. The separated saturated steam is slightly superheated in the second-stage waste heat boiler 19 and then sent into the low-grade steam user 32 pipe network. The feed water of the medium-pressure section of the boiler is pressurized and sent into the second heater (medium-pressure economizer) in the second-stage waste heat boiler 19. After heat exchange, it enters the medium-pressure steam drum 17 of the flue gas waste heat boiler. Subsequently, natural circulation occurs in the first-stage waste heat boiler 18. The steam-water mixture generated after circulation is separated by the medium-pressure steam drum 17 of the flue gas waste heat boiler. The separated saturated steam is preliminarily superheated in the first-stage waste heat boiler 18 and then sent into the riser superheater 24 for superheating. The outlet of the third heater is connected to the inlet of the riser superheater 24, and the outlet of the riser superheater 24 is connected to the medium-grade steam user 31. The riser superheater 24 is arranged on the coke oven 1. A first pressure reducing valve 30 is arranged on the pipeline connecting the riser superheater 24 and the medium-grade steam user 31. The outlet of the first pressure reducing valve 30 provides low-pressure steam, which can be flexibly allocated according to the demand for low-grade steam usage.

[0039] Among them, the feed water of the low-pressure section of the boiler is pressurized by the first water pump 16, and the feed water of the medium-pressure section of the boiler is pressurized by the second water pump 15.

[0040] In order to facilitate the control of the flue gas flow direction of the coke oven 1, a first flue valve 35 is provided on the sub-flue gas pipeline at the front end of the first-stage waste heat boiler 18, a second flue valve 36 is provided on the sub-flue gas pipeline at the rear end of the second-stage waste heat boiler 19, and a third flue valve 37 is provided on the main flue gas pipeline. By controlling the opening or closing and the opening degree of the corresponding valves, the flow direction and flow rate of the flue gas are controlled. When the first flue valve 35 and the second flue valve 36 are closed and the third flue valve 37 is opened, the flue gas generated by the coke oven 1 directly flows to the chimney 34. When the first flue valve 35 and the second flue valve 36 are opened and the third flue valve 37 is closed, the flue gas generated by the coke oven 1 flows to the sub-flue gas pipeline. It can be understood that by adjusting the opening degree of the valves, the split flow rate of the flue gas in different channels can be adjusted.

[0041] In order to facilitate the treatment of the flowing flue gas, a dry desulfurization device 21 and a dust removal and denitrification integrated device 22 are provided on the pipeline between the first-stage waste heat boiler 18 and the second-stage waste heat boiler 19. The flue gas waste heat boiler adopts a dual-pressure boiler setting of the first-stage waste heat boiler 18 and the second-stage waste heat boiler 19 to produce medium-pressure steam and low-pressure steam respectively. By setting the dry desulfurization device 21 and the dust removal and denitrification integrated device 22, the flue gas is desulfurized, dust-removed and denitrified. The flue gas is subjected to anti-overtemperature protective cooling in the first-stage waste heat boiler 18, then enters the dry desulfurization device 21 for desulfurization, and then passes through the dust removal and denitrification integrated device 22 for dust removal and denitrification. After the dust removal and denitrification, the flue gas is sent to the second-stage waste heat boiler 19 for heat recovery and then sent back to the chimney 34 through the induced draft fan 23 to complete the process flow. Under the condition of the same waste heat, the steam in the first-stage waste heat boiler 18 is superheated through the riser superheater 24 to produce medium-pressure steam. The flue gas waste heat boiler can produce both low-pressure steam and medium-pressure steam. Under the condition of the same waste heat, the total steam volume of the medium-pressure steam and the low-pressure steam is reduced, reducing the situation of excessive steam discharge, and at the same time, solving the problem of waste caused by excessive low-pressure steam discharge.

[0042] Further, an upcomer evaporator 25 is also provided on the coke oven 1. The upcomer evaporator 25 and the upcomer steam drum 27 form a circulation loop, and a forced circulation pump 33 is provided on this circulation loop. The inlet of the upcomer steam drum 27 is communicated with the demineralized water deaerator, and the outlet of the upcomer steam drum 27 is communicated with the inlet of the upcomer superheater 24. A low-pressure steam output branch is provided on the pipeline connecting the upcomer steam drum 27 and the upcomer superheater 24, and a second pressure reducing valve 26 is provided on the low-pressure steam output branch. After being reduced in pressure by the second pressure reducing valve 26, low-pressure steam is provided. During operation, the boiler feed water is pressurized by the second water pump 15 and then sent into the upcomer steam drum 27, and then enters the upcomer evaporator 25 through the forced circulation pump 33 for forced circulation. The steam-water mixture generated after forced circulation is separated by the upcomer steam drum 27, and the separated saturated steam is superheated by the upcomer superheater 24 and then sent into the medium-grade steam pipe network.

[0043] Among them, the outlet of the upcomer superheater 24 is also communicated with the heating inlet of the rich oil heater 28. The heating outlet of the rich oil heater 28 is communicated with the flash tank 29. The low-pressure steam flashed by the flash tank 29 flows into the low-grade steam user 32, and the high-temperature water flashed by the flash tank 29 flows into the low-pressure heater. The low-pressure heater is used to heat the liquid flowing into the demineralized water deaerator. The rich oil heater 28 indirectly exchanges heat between the medium-grade steam and the chemical production process oil. According to the plant layout, the medium-grade steam source generally comes from the upcomer superheater 24, and the exhaust steam of the high-pressure cylinder 5 of the steam turbine is used as a standby steam source. After the medium-grade steam condenses and exchanges heat, it becomes medium-pressure saturated water and enters the flash tank 29 to flash into low-pressure steam and high-temperature water at the corresponding pressure by using the residual pressure. The low-pressure steam is introduced into the low-grade steam pipe network, and the high-temperature water is led out from the liquid outlet at the bottom of the flash tank 29, and after being reduced to a suitable temperature by the low-pressure heater, it safely enters the demineralized water deaerator.

[0044] To improve the reliability of the system, the demineralized water deaerator includes a first demineralized water deaerator 14 and a second demineralized water deaerator 12. The first demineralized water deaerator 14 is connected to the second-stage waste heat boiler 19 and the riser steam drum 27 to provide demineralized water for both. The second demineralized water deaerator 12 is connected to the superheater of the coke dry quenching waste heat boiler 2 to provide demineralized water for it. A secondary economizer 4 is provided on the pipeline connecting the second demineralized water deaerator 12 and the superheater of the coke dry quenching waste heat boiler 2. In the prior art, the riser superheater 24 and the flue gas waste heat boiler are provided with separate demineralized water deaerators, that is, separate deaerators are provided for the riser waste heat utilization and the flue gas waste heat utilization in the corresponding workshops. Due to the particularity of the coking plant, there is no suitable maintenance time for the riser waste heat utilization and the flue gas demineralized water deaerator. If the demineralized water deaerator fails, the deaeration effect will be affected. In the present utility model, the deaerators for the riser waste heat utilization and the flue gas waste heat utilization both adopt the first demineralized water deaerator 14 and are jointly arranged in the coke dry quenching boiler feed water pump house. The second demineralized water deaerator 12 can be used as a backup for the first demineralized water deaerator 14, reducing the investment in the deaerator while increasing the reliability of the system. The deaeration system is centrally controlled, reducing the manual inspection and operation intensity.

[0045] To facilitate the steam-water separation of the fluid heated by the coke dry quenching waste heat boiler 2, a coke dry quenching boiler steam drum 3 used in conjunction with the coke dry quenching waste heat boiler 2 is also provided. The boiler feed water is pressurized by a third water pump 38 and then sent into the secondary economizer 4, and then enters the coke dry quenching waste heat boiler 2. After being heated in the boiler, it enters the coke dry quenching boiler steam drum 3. The steam-water mixture generated by the natural circulation of the coke dry quenching waste heat boiler 2 is separated by the coke dry quenching boiler steam drum 3. The separated saturated steam is superheated by two-stage superheaters and then sent from the first superheater outlet 201 to the high-grade steam pipe network and sent to the high-pressure cylinder 5 of the steam turbine for power generation. A second superheater 204 is provided between the two first superheaters 203 of the coke dry quenching waste heat boiler 2. The second superheater 204 is used to reheate the steam flowing out of the high-pressure cylinder 5 of the steam turbine, and then the steam flows into the low-pressure cylinder 6 of the steam turbine for power generation.

[0046] In one embodiment, both the first demineralized water deaerator 14 and the second demineralized water deaerator 12 are connected to the first steam outlet 601 of the low-pressure cylinder 6 of the steam turbine. The liquid outlet 603 of the low-pressure cylinder 6 of the steam turbine is connected to the liquid inlet of the second demineralized water deaerator 12. A low-pressure heater is provided on the pipeline connecting the liquid outlet 603 and the liquid inlet of the second demineralized water deaerator 12. The low-pressure cylinder 6 of the steam turbine is also provided with a second steam outlet 602. The steam flowing out of the second steam outlet 602 is used to heat the fluid flowing through the low-pressure heater, and the cooled fluid flows into the pipeline connecting the liquid outlet 603 and the second demineralized water deaerator 12. A condenser 8 and the low-pressure heater are sequentially arranged on the pipeline connecting the liquid outlet 603 of the low-pressure cylinder 6 of the steam turbine and the liquid inlet of the second demineralized water deaerator 12, and the condenser 8 is arranged close to the low-pressure cylinder 6 of the steam turbine. The demineralized water of the second demineralized water deaerator 12 is introduced from the first opening 801 on the condenser 8, and the steam flowing out of the second steam outlet 602 is introduced from the second opening 802 on the condenser 8 after being cooled in the low-pressure heater.

[0047] Furthermore, the low-pressure heater includes a first low-pressure heater 10 and a second low-pressure heater 11, and the first low-pressure heater 10 is arranged close to the condenser 8. The heating inlet of the first low-pressure heater 10 is connected to the second steam outlet 602 of the low-pressure cylinder 6 of the steam turbine, and the heating outlet of the first low-pressure heater 10 is connected to the condenser 8, so as to achieve the purpose of heating the demineralized water flowing through the first low-pressure heater 10. The heating inlet of the second low-pressure heater 11 is connected to the high-temperature water outlet of the flash tank 29 after flashing, and the heating outlet of the second low-pressure heater 11 is connected to the first demineralized water deaerator 14. The exhaust steam of the low-pressure cylinder 6 of the steam turbine enters the condenser 8. According to the demand of the make-up water volume of the whole-plant steam cycle, the demineralized water is introduced from the first opening 801, which not only reduces the load of the circulating cooling system and the cold source loss, but also pre-removes the oxygen from the make-up water and reduces the burden on the second demineralized water deaerator 12. The condensate water is sent to the second demineralized water deaerator 12 after being heated by the condensate pump 9 through the first low-pressure heater 10 and the second low-pressure heater 11. The first low-pressure heater 10 adopts the steam extraction and regeneration method of the steam turbine, and the heating steam is introduced into the condenser 8 from the second opening 802, reducing the cold source loss and improving the thermal efficiency of the unit. The second low-pressure heater 11 uses the high-temperature hot water discharged from the flash tank 29 for heat exchange, so that the high-temperature hot water can enter the first demineralized water deaerator 14.

[0048] The comprehensive utilization system of the coking plant waste heat resources of the present invention further includes a back-pressure steam turbine 13, and the back-pressure steam turbine 13 is used to provide power for the water pump arranged on the liquid outlet pipeline of the demineralized water deaerator, so that the water pump is driven by steam, reducing the factory power consumption, reducing the number of energy conversions, and improving the energy utilization rate. The power input end of the water pump is connected to the power output end of the back-pressure steam turbine 13, the steam input port of the back-pressure steam turbine 13 is connected to the outlet of the riser superheater 24, and the steam output port of the back-pressure steam turbine 13 is connected to the low-grade steam user 32. As Figure 1and Figure 5 As shown in Figure 5 , the third water pump 38 is driven by a back-pressure steam turbine 13.

[0049] The comprehensive utilization system of the waste heat resources in the coking plant of the present utility model can produce high-grade steam, medium-grade steam and low-grade steam. The high-grade steam is produced by the utilization of the waste heat from coke dry quenching and all enters the high-pressure cylinder 5 of the steam turbine to make full use of power generation. The medium-grade steam is the combined superheated steam of the waste heat from the riser pipe and the superheated steam at the outlet of the high-pressure cylinder 5 of the steam turbine, which is used for the rich oil heater 28 and the regeneration tower process in the crude benzene section; it is used for driving the back-pressure steam turbine 13; the remaining part is reheated by the waste heat boiler 2 of coke dry quenching and then all enters the low-pressure cylinder 6 of the steam turbine to make full use of it. The low-grade steam is produced by the second-stage waste heat boiler 19 to produce low-pressure steam; the flash tank 29 produces low-pressure saturated steam; the outlet of the back-pressure steam turbine 13 driving produces low-pressure steam, which is used for the steam consumption of the low-pressure steam pipe network of the whole plant, and the insufficient part is supplemented by reducing the pressure of the saturated steam of the waste heat from the riser pipe and the second pressure reducing valve 26. It is made full use of without remainder. The steam is configured in three grades to improve the steam quality as much as possible by using the waste heat resources and improve the power generation efficiency. The high-grade steam increases the steam parameters and the power generation amount. The medium-grade steam is configured according to the usage gap of the low-grade steam, and the back-pressure steam turbine of the medium-grade steam is driven to balance the low-grade steam. The excess part of the medium-grade steam is reheated by the waste heat boiler 2 of coke dry quenching and then continues to generate power. The low-grade steam adopts a slightly superheated scheme to reduce the large amount of working medium loss and heat loss of the traditional saturated steam.

[0050] The comprehensive utilization system of the waste heat resources in the coking plant of the present utility model reduces the dependence of the coking plant on the surrounding plants, improves the stability, makes full use of the waste heat, and the produced steam is self-used without being forced to be sent out due to excessive steam. The setting of the first-stage waste heat boiler 18 improves the steam parameters, realizes the cascade utilization of energy, prevents overheating, and protects the normal operation of the subsequent processes. The exhaust steam of the high-pressure cylinder 5 of the steam turbine of the present utility model is used as the pressure parameter of the medium-grade steam in the plant. The medium-grade steam is coordinately distributed to fully meet the self-use of the medium-grade steam in the plant and the demand for steam driving. Then, according to the load change of the low-grade steam, the remaining medium-grade steam is controlled for reheating power generation. It achieves the full circulation of the working medium, the perfect regulation of the system, and the full utilization of energy.

[0051] The comprehensive utilization system of waste heat resources in a coking plant of the present utility model can improve the quality of waste heat steam as much as possible, fully consider the actual steam demand of the whole plant, and achieve cascaded utilization of energy. It integrates the steam parameters of the whole plant, and according to the change of the steam load of the whole plant, all the surplus steam is converted into electric energy. It has a high working medium recovery rate and high flexibility. From the perspective of heat balance, the waste heat energy is converted into "plant steam + self-use electricity + external power supply". On the premise of meeting the plant steam, the higher the power generation, the higher the conversion rate of waste heat utilization. Increasing the power generation is to improve the steam cycle efficiency. The present utility model adopts the mode of "steam drive + heat", realizes part of the self-use electricity through steam drive, reduces the energy conversion links, has certain energy-saving benefits, and uses the steam after driving for low-grade steam supply, so as to achieve the purpose of reducing the amount of working medium in the condenser 8. In addition, by trying to improve the steam parameters of the waste heat utilization of the riser and flue gas, and reducing the steam output, the same purpose can also be achieved.

[0052] In the description of this solution, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "vertical", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to this solution.

[0053] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this solution, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0054] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other. The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A comprehensive utilization system for waste heat resources in a coking plant, characterized in that, It includes a coke dry quenching waste heat boiler, a flue gas waste heat boiler, a demineralized water deaerator, a high-pressure cylinder of a steam turbine, and a low-pressure cylinder of a steam turbine. The outlet of the first superheater of the coke dry quenching waste heat boiler is communicated with the steam inlet of the high-pressure cylinder of the steam turbine. The exhaust port of the high-pressure cylinder of the steam turbine is communicated with a medium-grade steam user and / or the inlet of the second superheater of the coke dry quenching waste heat boiler. The outlet of the second superheater is communicated with the steam inlet of the low-pressure cylinder of the steam turbine. The exhaust port of the low-pressure cylinder of the steam turbine is communicated with the demineralized water deaerator; The flue gas waste heat boiler is arranged on the connecting pipeline between the coke oven and the chimney. The heater in the flue gas waste heat boiler is communicated with the demineralized water deaerator. A part of the fluid flowing through the heater in the flue gas waste heat boiler flows to a low-grade steam user, and the other part flows to a medium-grade steam user.

2. The comprehensive utilization system of the waste heat resources of the coking plant according to claim 1, characterized in that, The flue gas waste heat boiler includes a first-stage waste heat boiler and a second-stage waste heat boiler connected by a flue gas dividing pipeline. The inlet and outlet of the flue gas dividing pipeline are both communicated with the main flue gas pipeline. The main flue gas pipeline is connected between the chimney and the coke oven; The first-stage waste heat boiler is arranged near the inlet end of the flue gas dividing pipeline, and the second-stage waste heat boiler is arranged near the outlet end of the flue gas dividing pipeline. The fluid flowing out of the demineralized water deaerator enters the first heater and the second heater in the second-stage waste heat boiler. The outlet of the first heater is communicated with the low-grade steam user, and the outlet of the second heater is communicated with the third heater in the first-stage waste heat boiler.

3. The comprehensive utilization system of the waste heat resources of the coking plant according to claim 2, characterized in that, The first heater is in a circulating connection with the low-pressure steam drum of the flue gas waste heat boiler, and the third heater is in a circulating connection with the medium-pressure steam drum of the flue gas waste heat boiler; The outlet of the third heater is communicated with the inlet of the riser superheater. The outlet of the riser superheater is communicated with the medium-grade steam user. The riser superheater is arranged on the coke oven.

4. The comprehensive utilization system of the waste heat resources of the coking plant according to claim 2, wherein, A first flue gas valve is arranged on the flue gas dividing pipeline at the front end of the first-stage waste heat boiler, a second flue gas valve is arranged on the flue gas dividing pipeline at the rear end of the second-stage waste heat boiler, and a third flue gas valve is arranged on the main flue gas pipeline; A dry desulfurization device and a dust removal and denitration integrated device are arranged on the pipeline between the first-stage waste heat boiler and the second-stage waste heat boiler.

5. The comprehensive utilization system of the waste heat resources of the coking plant according to claim 3, characterized in that, A riser evaporator is also arranged on the coke oven. The riser evaporator and the riser steam drum form a circulation loop. The inlet of the riser steam drum is communicated with the demineralized water deaerator, and the outlet of the riser steam drum is communicated with the inlet of the riser superheater.

6. The comprehensive utilization system of the waste heat resources of the coking plant according to claim 3, wherein, The outlet of the riser superheater is also communicated with the heating inlet of the rich oil heater. The heating outlet of the rich oil heater is communicated with a flash tank. The low-pressure steam flashed by the flash tank flows into the low-grade steam user, and the high-temperature water flashed by the flash tank flows into a low-pressure heater. The low-pressure heater is used to heat the liquid flowing into the demineralized water deaerator.

7. The comprehensive utilization system of waste heat resources in a coking plant according to claim 5, characterized in that, The demineralized water deaerator includes a first demineralized water deaerator and a second demineralized water deaerator. The first demineralized water deaerator is connected to the second-stage waste heat boiler and the riser steam drum to supply demineralized water to both of them. The second demineralized water deaerator is connected to the superheater of the coke dry quenching waste heat boiler to supply demineralized water to it. A secondary economizer is provided on the pipeline where the second demineralized water deaerator is connected to the superheater of the coke dry quenching waste heat boiler.

8. The comprehensive utilization system of the waste heat resources of the coking plant according to claim 7, characterized in that, The first demineralized water deaerator and the second demineralized water deaerator are connected to the steam outlet of the low-pressure cylinder of the steam turbine. The liquid outlet of the low-pressure cylinder of the steam turbine is connected to the liquid inlet of the second demineralized water deaerator. A condenser and a low-pressure heater are sequentially arranged on the pipeline where the liquid outlet of the low-pressure cylinder of the steam turbine is connected to the liquid inlet of the second demineralized water deaerator. The condenser is arranged close to the low-pressure cylinder of the steam turbine.

9. The comprehensive utilization system of the waste heat resources of the coking plant according to claim 8, characterized in that, The low-pressure heater includes a first low-pressure heater and a second low-pressure heater. The first low-pressure heater is arranged close to the condenser. The heating inlet of the first low-pressure heater is connected to the steam outlet of the low-pressure cylinder of the steam turbine, and the heating outlet of the first low-pressure heater is connected to the condenser. The heating inlet of the second low-pressure heater is connected to the high-temperature water outlet of the flash tank after flashing, and the heating outlet of the second low-pressure heater is connected to the first demineralized water deaerator.

10. The comprehensive utilization system of the waste heat resources of a coking plant according to claim 3, characterized in that, It also includes a back-pressure steam turbine. A water pump is provided on the liquid outlet pipeline of the demineralized water deaerator. The power input end of the water pump is connected to the power output end of the back-pressure steam turbine. The steam input port of the back-pressure steam turbine is connected to the outlet of the riser superheater, and the steam output port of the back-pressure steam turbine is connected to the low-grade steam user.

Images