A Urea Hydrolysis to Ammonia Heating and Steam Supply System and Method with a Steam Injector

Abstract

The present invention discloses a urea hydrolysis ammonia production heat supply and steam supply system and method with a steam ejector, including a steam generator, a steam turbine, the second stage of the steam turbine unit, the third stage of the steam turbine unit, the fourth stage of the steam turbine unit, a urea hydrolysis reactor, a storage tank urea solution pipeline, a urea solution storage tank, a dissolving tank urea solution pipeline, a spray desuperheater, a steam ejector, a high-pressure steam pipeline regulating valve of the steam ejector, a third-stage steam extraction pipeline regulating valve of the steam turbine, a fourth-stage steam extraction pipeline regulating valve of the steam turbine, a steam pipeline regulating valve at the outlet of the steam ejector, a supplementary heat steam regulating valve for the storage tank urea solution pipeline, and an ejector steam regulating valve of the steam ejector. The system and method have the characteristics of high flexibility, small waste of steam quality, high entrainment coefficient of the steam ejector, and strong entrainment capacity.

Description

Technical Field

[0001] The present invention relates to a urea hydrolysis ammonia production heat supply and steam supply system and method, and particularly to a urea hydrolysis ammonia production heat supply and steam supply system and method with a steam ejector. Background Art

[0002] With the development of society, the state has become increasingly strict with flue gas prevention and control. In the field of flue gas denitrification, urea hydrolysis ammonia production overcomes the safety problems existing in the use of liquid ammonia in coal-fired power plant flue gas denitrification. In the urea hydrolysis process, steam is an indispensable energy source for the hydrolysis process and plays an important role in processes such as heating the urea dissolution tank, heating the urea solution storage tank, heating the hydrolysis reactor, and pipeline tracing. In the hydrolysis process, a large amount of steam is consumed; in the previous urea hydrolysis steam supply system, steam is reduced in temperature and pressure to meet the requirements of the hydrolysis process, resulting in waste of the steam energy level of the steam supply. In the coupled system of a thermal power unit combined with urea hydrolysis ammonia production for heat supply and steam supply, the steam ejector plays an important role. The steam ejector can solve the problem of steam parameter mismatch between the steam extraction of the power plant and the urea hydrolysis ammonia production heat supply and steam supply system; compared with the traditional desuperheating and pressure reducing valve, the steam ejector can entrain some low-parameter steam, thereby achieving the purpose of energy conservation and consumption reduction.

[0003] In the industrial steam supply system, desuperheating and pressure reducing valves are mostly used, resulting in a large waste of the steam quality; in addition, the flexibility of the urea hydrolysis ammonia production heat supply and steam supply system is not high enough. When the thermal power unit operates at low load, the performance of the steam ejector deteriorates under variable working conditions, resulting in a decrease in the entrainment coefficient and a decline in the entrainment capacity, directly affecting the operation of the urea hydrolysis ammonia production heat supply and steam supply system. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned disadvantages of the prior art and provide a urea hydrolysis ammonia production heat supply and steam supply system and method with a steam ejector, which have the characteristics of high flexibility, small waste of steam quality, high entrainment coefficient of the steam ejector, and strong entrainment capacity.

[0005] To achieve the above purpose, the urea hydrolysis ammonia production heat supply and steam supply system with a steam ejector described in the present invention includes a steam generator, a steam turbine, the second stage of the steam turbine unit, the third stage of the steam turbine unit, the fourth stage of the steam turbine unit, a urea hydrolysis reactor, a storage tank urea solution pipeline, a urea solution storage tank, a dissolution tank urea solution pipeline, a spray desuperheater, a steam ejector, a steam ejector high-pressure steam pipeline regulating valve, a third-stage steam turbine extraction pipeline regulating valve, a fourth-stage steam turbine extraction pipeline regulating valve, a steam ejector outlet steam pipeline regulating valve, a storage tank urea solution pipeline supplementary heat steam regulating valve, and a steam ejector entrained steam regulating valve;

[0006] The high-temperature and high-pressure steam outlet of the steam generator is connected to the inlet of the steam turbine. The steam outlet pipeline of the second stage of the steam turbine unit is connected to the inlet of the high-pressure steam pipeline of the steam ejector through the regulating valve of the high-pressure steam pipeline of the steam ejector. The outlet of the steam ejector is connected to the inlet of the regulating valve of the steam pipeline at the outlet of the steam ejector.

[0007] The steam outlet pipeline of the third stage of the steam turbine unit is connected to the inlet of the regulating valve of the extraction steam pipeline of the third-stage steam turbine. The steam outlet pipeline of the fourth stage of the steam turbine unit is connected to the inlet of the regulating valve of the extraction steam pipeline of the fourth-stage steam turbine. The outlet of the regulating valve of the supplementary heat steam pipeline of the urea solution pipeline in the storage tank is connected to the inlet of the urea solution pipeline in the storage tank.

[0008] The outlet of the regulating valve of the extraction steam pipeline of the third-stage steam turbine, the outlet of the regulating valve of the extraction steam pipeline of the fourth-stage steam turbine, the outlet of the regulating valve of the steam pipeline at the outlet of the steam ejector, and the inlet of the regulating valve of the supplementary heat steam pipeline of the urea solution pipeline in the storage tank are all connected to the inlet of the desuperheater by water injection. The outlet of the desuperheater by water injection is connected to the inlet of the heating steam pipeline of the urea hydrolysis reactor.

[0009] The outlet of the urea solution pipeline in the dissolution tank is connected to the inlet of the regulating valve of the entrained steam of the steam ejector. The outlet of the regulating valve of the entrained steam of the steam ejector is connected to the inlet of the entrained steam of the steam ejector.

[0010] The steam outlet pipeline of the second stage of the steam turbine unit is connected to the inlet of the high-pressure steam pipeline of the steam ejector through a separator and the regulating valve of the high-pressure steam pipeline of the steam ejector.

[0011] It also includes a urea dissolution tank. The outlet of the heating steam pipeline of the urea hydrolysis reactor is connected to the inlet of the heating steam pipeline of the urea solution pipeline in the storage tank. The outlet of the heating steam pipeline of the urea solution pipeline in the storage tank is connected to the inlet of the heating pipeline of the urea solution storage tank. The outlet of the heating pipeline of the urea solution storage tank is connected to the inlet of the urea solution pipeline in the dissolution tank. The outlet of the urea solution pipeline in the dissolution tank is connected to the inlet of the heating pipeline of the urea dissolution tank. The outlet of the heating pipeline of the urea dissolution tank is connected to the power plant return water pipeline outside. The urea solution outlet of the urea dissolution tank is connected to the urea solution inlet of the urea solution storage tank. The urea solution outlet of the urea solution storage tank is connected to the urea solution inlet of the urea hydrolysis reactor. The urea hydrolysis product outlet of the urea hydrolysis reactor is connected to the SCR reactor outside.

[0012] The urea solution outlet of the urea dissolution tank is connected to the urea solution inlet of the urea solution storage tank through a urea solution transfer pump in the dissolution tank.

[0013] The urea solution outlet of the urea solution storage tank is connected to the urea solution inlet of the urea hydrolysis reactor through a urea solution transfer pump in the storage tank.

[0014] It also includes a power plant condenser, a low-pressure heater, a deaerator and a high-pressure regenerative heater; the exhaust port of the steam turbine unit is connected to the inlet of the deaerator through the power plant condenser and the low-pressure heater, the outlet of the deaerator is connected to the inlet of the high-pressure regenerative heater, and the outlet of the high-pressure regenerative heater is connected to the inlet of the steam generator.

[0015] The exhaust port of the steam turbine unit is connected to the inlet of the deaerator through the power plant condenser, a condensate pump and the low-pressure heater.

[0016] The outlet of the deaerator is connected to the inlet of the high-pressure regenerative heater through a feed water pump.

[0017] The method for heating and steam supply of urea hydrolysis to produce ammonia with a steam ejector according to the present invention includes:

[0018] In the operation mode under high load of the power plant, the steam ejector, the regulating valve of the high-pressure steam pipeline of the steam ejector, the regulating valve of the outlet steam pipeline of the steam ejector and the regulating valve of the entrained steam of the steam ejector are all in the working state; the steam ejector extracts the exhaust steam of the second stage of the steam turbine unit and entrains the low-temperature and low-pressure water vapor in the urea solution pipeline of the dissolution tank; according to the demand of the steam consumption, the opening degree of the regulating valve of the entrained steam of the steam ejector is adjusted to realize the flow control of the extracted steam. At this time, the regulating valve of the extraction steam pipeline of the third-stage steam turbine is closed, and the regulating valve of the extraction steam pipeline of the fourth-stage steam turbine is closed. When the temperature in the urea solution pipeline of the storage tank meets the insulation temperature, the regulating valve of the supplementary heat steam of the urea solution pipeline of the storage tank is closed, otherwise, the regulating valve of the supplementary heat steam of the urea solution pipeline of the storage tank is opened, and by adjusting the opening degree of the regulating valve of the supplementary heat steam of the urea solution pipeline of the storage tank, the temperature requirement of the urea solution pipeline of the storage tank is met; the steam output by the steam ejector enters the desuperheater through the regulating valve of the outlet steam pipeline of the steam ejector, and then enters the heating steam pipeline of the urea hydrolysis reactor after being desuperheated by spraying water in the desuperheater;

[0019] In the operation mode under the intermediate load of the power plant, the regulating valve of the extraction steam pipeline of the fourth-stage steam turbine is opened, and the flow rate of the extracted steam is controlled by adjusting the opening degree of the regulating valve of the extraction steam pipeline of the fourth-stage steam turbine; at this time, the steam ejector stops working, and the regulating valve of the high-pressure steam pipeline of the steam ejector, the regulating valve of the outlet steam pipeline of the steam ejector and the regulating valve of the entrained steam of the steam ejector are all in the closed state, and the regulating valve of the extraction steam pipeline of the third-stage steam turbine is closed; when the temperature in the urea solution pipeline of the storage tank meets the insulation temperature, the regulating valve of the supplementary heat steam of the urea solution pipeline of the storage tank is closed, otherwise, the regulating valve of the supplementary heat steam of the urea solution pipeline of the storage tank is opened, and by adjusting the opening degree of the regulating valve of the supplementary heat steam of the urea solution pipeline of the storage tank, the temperature requirement of the urea solution pipeline of the storage tank is met. The steam output by the regulating valve of the extraction steam pipeline of the fourth-stage steam turbine enters the desuperheater and then enters the heating steam pipeline of the urea hydrolysis reactor after being desuperheated by spraying water in the desuperheater;

[0020] Under the low-load operation mode of the power plant, open the regulating valve of the third-stage steam extraction pipeline of the steam turbine, and control the steam extraction flow rate by adjusting the opening degree of the regulating valve of the third-stage steam extraction pipeline of the steam turbine; at this time, the steam ejector stops working, and the regulating valves of the high-pressure steam pipeline of the steam ejector, the outlet steam pipeline of the steam ejector, and the entrained steam regulating valve of the steam ejector are all in the closed state, and the regulating valve of the fourth-stage steam extraction pipeline of the steam turbine is closed; when the temperature in the urea solution pipeline of the storage tank meets the insulation temperature, the heat-supplementing steam regulating valve of the urea solution pipeline of the storage tank is closed, otherwise, open the heat-supplementing steam regulating valve of the urea solution pipeline of the storage tank, and adjust the opening degree of the heat-supplementing steam regulating valve of the urea solution pipeline of the storage tank to meet the temperature requirements of the urea solution pipeline of the storage tank. The steam output from the regulating valve of the third-stage steam extraction pipeline of the steam turbine enters the desuperheater, and after desuperheating by spraying water, it is sent into the heating steam pipeline of the urea hydrolysis reactor.

[0021] The present invention has the following beneficial effects:

[0022] When the urea hydrolysis ammonia production heat supply and steam supply system and method with a steam ejector of the present invention are specifically operated, the entrained steam is sourced from the steam extraction of the second stage, the third stage, and the fourth stage of the steam turbine unit. At the same time, a steam ejector is added, and regulating valves for the high-pressure steam pipeline of the steam ejector, the third-stage steam extraction pipeline of the steam turbine, the fourth-stage steam extraction pipeline of the steam turbine, the outlet steam pipeline of the steam ejector, the heat-supplementing steam regulating valve of the urea solution pipeline of the storage tank, and the entrained steam regulating valve of the steam ejector are provided. By controlling the positions of the regulating valves to switch the steam sources, on the premise of ensuring the normal operation of the urea hydrolysis ammonia production heat supply and steam supply system, the cascade utilization of energy is realized to a large extent, the steam consumption cost is reduced, the steam ejector does not require other energy consumption, works stably, and the equipment has high safety and reliability, with the characteristics of high flexibility and small waste of steam quality. It preferably solves the problem of flexible switching of the steam source position, thereby reducing the steam cost of the power plant for steam supply and saving energy on the premise of meeting the steam demand for urea hydrolysis ammonia production. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the present invention.

[0024] Among them, 1 is a steam generator, 2 is the second stage of the steam turbine unit, 3 is the third stage of the steam turbine unit, 4 is the fourth stage of the steam turbine unit, 5 is a high-pressure regenerative heater, 6 is a feed water pump, 7 is a deaerator, 8 is a low-pressure heater, 9 is a condensate pump, 10 is a power plant condenser, 11 is a separator, 12 is a urea hydrolysis reactor, 13 is a storage tank urea solution transfer pump, 14 is a storage tank urea solution pipeline, 15 is a urea solution storage tank, 16 is a dissolution tank urea solution transfer pump, 17 is a dissolution tank urea solution pipeline, 18 is a urea dissolution tank, 19 is a spray desuperheater, 20 is a steam injector, 101 is a regulating valve for the high-pressure steam pipeline of the steam injector, 102 is a regulating valve for the extraction steam pipeline of the third-stage steam turbine, 103 is a regulating valve for the extraction steam pipeline of the fourth-stage steam turbine, 104 is a regulating valve for the outlet steam pipeline of the steam injector, 105 is a regulating valve for the supplementary heating steam of the storage tank urea solution pipeline, and 106 is a regulating valve for the ejector steam of the steam injector. Detailed implementation manners

[0025] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present invention disclosure. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessarily confusing the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0026] The structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures and their relative sizes and positional relationships are only exemplary, and may actually deviate due to manufacturing tolerances or technical limitations. Those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0027] Refer to Figure 1, the urea hydrolysis ammonia production heat and steam supply system with a steam ejector according to the present invention includes a steam generator 1, the second stage of a steam turbine unit 2, the third stage of a steam turbine unit 3, the fourth stage of a steam turbine unit 4, a high-pressure regenerative heater 5, a feed water pump 6, a deaerator 7, a low-pressure heater 8, a condensate pump 9, a power plant condenser 10, a separator 11, a urea hydrolysis reactor 12, a storage tank urea solution transfer pump 13, a storage tank urea solution pipeline 14, a urea solution storage tank 15, a dissolution tank urea solution transfer pump 16, a dissolution tank urea solution pipeline 17, a urea dissolution tank 18, a spray desuperheater 19, a steam ejector 20, a steam ejector high-pressure steam pipeline regulating valve 101, a third-stage steam turbine extraction pipeline regulating valve 102, a fourth-stage steam turbine extraction pipeline regulating valve 103, a steam ejector outlet steam pipeline regulating valve 104, a storage tank urea solution pipeline supplementary heat steam regulating valve 105, and a steam ejector entrained steam regulating valve 106;

[0028] The high-temperature and high-pressure steam outlet of the steam generator 1 is connected to the inlet of the steam turbine. The steam outlet pipeline of the second stage 2 of the steam turbine unit is connected to the inlet of the high-pressure steam inlet pipeline of the steam ejector 20 through the separator 11 and the regulating valve 101 of the high-pressure steam pipeline of the steam ejector. The outlet of the steam ejector 20 is connected to the inlet of the regulating valve 104 of the steam pipeline at the outlet of the steam ejector. The steam outlet pipeline of the third stage 3 of the steam turbine unit is connected to the inlet of the regulating valve 102 of the extraction steam pipeline of the third-stage steam turbine. The steam outlet pipeline of the fourth stage 4 of the steam turbine unit is connected to the inlet of the regulating valve 103 of the extraction steam pipeline of the fourth-stage steam turbine. The outlet of the regulating valve 105 for supplementary heating steam of the urea solution pipeline of the storage tank is connected to the inlet of the urea solution pipeline 14 of the storage tank. The outlets of the regulating valve 102 of the extraction steam pipeline of the third-stage steam turbine, the outlet of the regulating valve 103 of the extraction steam pipeline of the fourth-stage steam turbine, the outlet of the regulating valve 104 of the steam pipeline at the outlet of the steam ejector, and the inlet of the regulating valve 105 for supplementary heating steam of the urea solution pipeline of the storage tank are all connected to the inlet of the desuperheater 19. The outlet of the desuperheater 19 is connected to the inlet of the heating steam pipeline of the urea hydrolysis reactor 12. The outlet of the heating steam pipeline of the urea hydrolysis reactor 12 is connected to the inlet of the heating steam pipeline of the urea solution pipeline 14 of the storage tank. The outlet of the heating steam pipeline of the urea solution pipeline 14 of the storage tank is connected to the inlet of the heating pipeline of the urea solution storage tank 15. The outlet of the heating pipeline of the urea solution storage tank 15 is connected to the inlet of the urea solution pipeline 17 of the dissolution tank. The outlet of the urea solution pipeline 17 of the dissolution tank is connected to the inlet of the heating pipeline of the urea dissolution tank 18 and the inlet of the regulating valve 106 for the entrained steam of the steam ejector. The outlet of the regulating valve 106 for the entrained steam of the steam ejector is connected to the entrained steam inlet of the steam ejector 20. The outlet of the heating pipeline of the urea dissolution tank 18 is connected to the power plant return water pipeline. The urea solution outlet of the urea dissolution tank 18 is connected to the urea solution inlet of the urea solution storage tank 15 through the urea solution transfer pump 16 of the dissolution tank. The urea solution outlet of the urea solution storage tank 15 is connected to the urea solution inlet of the urea hydrolysis reactor 12 through the urea solution transfer pump 13 of the storage tank. The urea hydrolysis product outlet of the urea hydrolysis reactor 12 is connected to the external SCR reactor.

[0029] The exhaust port of the steam turbine unit is connected to the inlet of the deaerator 7 through the power plant condenser 10, the condensate pump 9, and the low-pressure heater 8. The outlet of the deaerator 7 is connected to the inlet of the high-pressure regenerative heater 5 through the feed water pump 6. The outlet of the high-pressure regenerative heater 5 is connected to the inlet of the steam generator 1.

[0030] The method for producing ammonia by urea hydrolysis with heat supply and steam supply using a steam ejector according to the present invention includes:

[0031] Under the operation mode at high load in the power plant, when the exhaust steam of the intermediate pressure cylinder of the fourth stage 4 of the steam turbine unit operates at a load of 920 - 1060 kPa (85% THA - 100% THA), the steam ejector 20, the regulating valve 101 of the high-pressure steam pipeline of the steam ejector, the regulating valve 104 of the outlet steam pipeline of the steam ejector, and the regulating valve 106 of the entrained steam of the steam ejector are all in the working state; the steam ejector 20 extracts the exhaust steam of the second stage 2 of the steam turbine unit and entrains the low-temperature and low-pressure water vapor in the urea solution pipeline 17 of the dissolution tank; according to the demand of the steam consumption, the opening of the regulating valve 106 of the entrained steam of the steam ejector is adjusted to achieve the flow control of the extracted steam. At this time, the regulating valve 102 of the extraction steam pipeline of the third-stage steam turbine is closed, and the regulating valve 103 of the extraction steam pipeline of the fourth-stage steam turbine is closed. When the temperature in the urea solution pipeline 14 of the storage tank meets the heat preservation temperature, the regulating valve 105 of the supplementary heat steam of the urea solution pipeline of the storage tank is closed, otherwise, the regulating valve 105 of the supplementary heat steam of the urea solution pipeline of the storage tank is opened, and by adjusting the opening of the regulating valve 105 of the supplementary heat steam of the urea solution pipeline of the storage tank, the temperature requirement of the urea solution pipeline 14 of the storage tank is met; the steam output by the steam ejector 20 enters the desuperheater 19 through the regulating valve 104 of the outlet steam pipeline of the steam ejector, and after being desuperheated by spraying water in the desuperheater 19, it enters the heating steam pipeline of the urea hydrolysis reactor 12.

[0032] Under the operation mode at intermediate load in the power plant, when the exhaust steam of the intermediate pressure cylinder of the fourth stage 4 of the steam turbine unit operates between a load of 750 kPa - 920 kPa (70% THA - 85% THA), the regulating valve 103 of the extraction steam pipeline of the fourth-stage steam turbine is opened, and the flow rate of the extracted steam is controlled by adjusting the opening of the regulating valve 103 of the extraction steam pipeline of the fourth-stage steam turbine; at this time, the steam ejector 20 stops working, and the regulating valve 101 of the high-pressure steam pipeline of the steam ejector, the regulating valve 104 of the outlet steam pipeline of the steam ejector, and the regulating valve 106 of the entrained steam of the steam ejector are all in the closed state, and the regulating valve 102 of the extraction steam pipeline of the third-stage steam turbine is closed; when the temperature in the urea solution pipeline 14 of the storage tank meets the heat preservation temperature, the regulating valve 105 of the supplementary heat steam of the urea solution pipeline of the storage tank is closed, otherwise, the regulating valve 105 of the supplementary heat steam of the urea solution pipeline of the storage tank is opened, and by adjusting the opening of the regulating valve 105 of the supplementary heat steam of the urea solution pipeline of the storage tank, the temperature requirement of the urea solution pipeline 14 of the storage tank is met. The steam output by the regulating valve 103 of the extraction steam pipeline of the fourth-stage steam turbine enters the desuperheater 19, and after being desuperheated by spraying water in the desuperheater 19, it enters the heating steam pipeline of the urea hydrolysis reactor 12.

[0033] Under the operation mode of the power plant at low load, when the exhaust steam of the intermediate pressure cylinder of the fourth stage 4 of the steam turbine unit operates below 750 kPa (70% THA load), at this time, open the regulating valve 102 of the extraction steam pipeline of the third-stage steam turbine, and control the flow rate of the extraction steam by adjusting the opening degree of the regulating valve 102 of the extraction steam pipeline of the third-stage steam turbine; at this time, the steam ejector 20 stops working, and the regulating valve 101 of the high-pressure steam pipeline of the steam ejector, the regulating valve 104 of the outlet steam pipeline of the steam ejector, and the regulating valve 106 of the ejector steam of the steam ejector are all in the closed state, and the regulating valve 103 of the extraction steam pipeline of the fourth-stage steam turbine is closed; when the temperature in the storage tank urea solution pipeline 14 meets the insulation temperature, the heat compensation steam regulating valve 105 of the storage tank urea solution pipeline is closed, otherwise, open the heat compensation steam regulating valve 105 of the storage tank urea solution pipeline, and adjust the opening degree of the heat compensation steam regulating valve 105 of the storage tank urea solution pipeline to meet the temperature requirement of the storage tank urea solution pipeline 14. The steam output by the regulating valve 102 of the extraction steam pipeline of the third-stage steam turbine enters the desuperheater 19 and is then sent to the heating steam pipeline of the urea hydrolysis reactor 12 after desuperheating by spraying water.

Claims

1. A urea hydrolysis ammonia production heat and steam supply system with a steam injector, characterized in that, It includes a steam generator (1), a steam turbine, the second stage (2) of the steam turbine unit, the third stage (3) of the steam turbine unit, the fourth stage (4) of the steam turbine unit, a urea hydrolysis reactor (12), a storage tank urea solution pipeline (14), a urea solution storage tank (15), a dissolution tank urea solution pipeline (17), a spray desuperheater (19), a steam ejector (20), a regulating valve (101) for the high-pressure steam pipeline of the steam ejector, a regulating valve (102) for the extraction steam pipeline of the third-stage steam turbine, a regulating valve (103) for the extraction steam pipeline of the fourth-stage steam turbine, a regulating valve (104) for the outlet steam pipeline of the steam ejector, a regulating valve (105) for the supplementary heat steam of the storage tank urea solution pipeline, and a regulating valve (106) for the entrained steam of the steam ejector; The high-temperature and high-pressure steam outlet of the steam generator (1) is connected to the inlet of the steam turbine. The steam outlet pipeline of the second stage (2) of the steam turbine unit is connected to the inlet of the high-pressure steam pipeline of the steam ejector (20) through the regulating valve (101) for the high-pressure steam pipeline of the steam ejector. The outlet of the steam ejector (20) is connected to the inlet of the regulating valve (104) for the outlet steam pipeline of the steam ejector; The steam outlet pipeline of the third stage (3) of the steam turbine unit is connected to the inlet of the regulating valve (102) for the extraction steam pipeline of the third-stage steam turbine. The steam outlet pipeline of the fourth stage (4) of the steam turbine unit is connected to the inlet of the regulating valve (103) for the extraction steam pipeline of the fourth-stage steam turbine. The outlet of the regulating valve (105) for the supplementary heat steam of the storage tank urea solution pipeline is connected to the inlet of the storage tank urea solution pipeline (14); The outlets of the regulating valve (102) for the extraction steam pipeline of the third-stage steam turbine, the regulating valve (103) for the extraction steam pipeline of the fourth-stage steam turbine, the regulating valve (104) for the outlet steam pipeline of the steam ejector, and the inlet of the regulating valve (105) for the supplementary heat steam of the storage tank urea solution pipeline are all connected to the inlet of the spray desuperheater (19). The outlet of the spray desuperheater (19) is connected to the inlet of the heating steam pipeline of the urea hydrolysis reactor (12); The outlet of the dissolution tank urea solution pipeline (17) is connected to the inlet of the regulating valve (106) for the entrained steam of the steam ejector. The outlet of the regulating valve (106) for the entrained steam of the steam ejector is connected to the entrained steam inlet of the steam ejector (20); The steam outlet pipeline of the second stage (2) of the steam turbine unit is connected to the inlet of the high-pressure steam pipeline of the steam ejector (20) through a separator (11) and the regulating valve (101) for the high-pressure steam pipeline of the steam ejector; It further includes a urea dissolving tank (18); the heating steam pipeline outlet of the urea hydrolysis reactor (12) is communicated with the heating steam pipeline inlet of the storage tank urea solution pipeline (14), the heating steam pipeline outlet of the storage tank urea solution pipeline (14) is communicated with the heating pipeline inlet of the urea solution storage tank (15), the heating pipeline outlet of the urea solution storage tank (15) is communicated with the inlet of the dissolving tank urea solution pipeline (17), the outlet of the dissolving tank urea solution pipeline (17) is communicated with the heating pipeline inlet of the urea dissolving tank (18), the heating pipeline outlet of the urea dissolving tank (18) is connected to the power plant return water pipeline outside, the urea solution outlet of the urea dissolving tank (18) is connected to the urea solution inlet of the urea solution storage tank (15), the urea solution outlet of the urea solution storage tank (15) is connected to the urea solution inlet of the urea hydrolysis reactor (12), and the urea hydrolysis product outlet of the urea hydrolysis reactor (12) is connected to the SCR reactor outside.

2. The urea hydrolysis ammonia production heat and steam supply system with a steam ejector according to claim 1, wherein The urea solution outlet of the urea dissolving tank (18) is connected to the urea solution inlet of the urea solution storage tank (15) through the dissolving tank urea solution transfer pump (16).

3. The urea hydrolysis ammonia production heat and steam supply system with a steam injector according to claim 1, characterized in that The urea solution outlet of the urea solution storage tank (15) is connected to the urea solution inlet of the urea hydrolysis reactor (12) through the storage tank urea solution transfer pump (13).

4. The urea hydrolysis ammonia production heat and steam supply system with a steam injector according to claim 1, characterized in that, It further includes a power plant condenser (10), a low-pressure heater (8), a deaerator (7) and a high-pressure regenerative heater (5); the exhaust port of the steam turbine unit is connected to the inlet of the deaerator (7) after passing through the power plant condenser (10) and the low-pressure heater (8), the outlet of the deaerator (7) is connected to the inlet of the high-pressure regenerative heater (5), and the outlet of the high-pressure regenerative heater (5) is connected to the inlet of the steam generator (1).

5. The urea hydrolysis ammonia production heat and steam supply system with a steam ejector according to claim 4, characterized in that, The exhaust port of the steam turbine unit is connected to the inlet of the deaerator (7) after passing through the power plant condenser (10), the condensate pump (9) and the low-pressure heater (8).

6. The urea hydrolysis ammonia production heat and steam supply system with a steam ejector according to claim 4, characterized in that, The outlet of the deaerator (7) is connected to the inlet of the high-pressure regenerative heater (5) through the feed water pump (6).

7. A method for supplying heat and steam in urea hydrolysis to produce ammonia with a steam injector, characterized in that, The urea hydrolysis ammonia production heat supply and steam supply system with a steam ejector according to claim 1, comprising: Under the operation mode of high load in the power plant, the steam ejector (20), the regulating valve (101) of the high-pressure steam pipeline of the steam ejector, the regulating valve (104) of the outlet steam pipeline of the steam ejector, and the regulating valve (106) of the entrained steam of the steam ejector are all in working state; the steam ejector (20) extracts the exhaust steam of the second stage (2) of the steam turbine unit and entrains the low-temperature and low-pressure water vapor in the urea solution pipeline (17) of the dissolution tank; according to the demand of the steam consumption, the opening degree of the regulating valve (106) of the entrained steam of the steam ejector is adjusted to realize the flow control of the extracted steam. At this time, the regulating valve (102) of the extraction steam pipeline of the third-stage steam turbine is closed, and the regulating valve (103) of the extraction steam pipeline of the fourth-stage steam turbine is closed. When the temperature in the urea solution pipeline (14) of the storage tank meets the heat preservation temperature, the regulating valve (105) of the supplementary heat steam of the urea solution pipeline of the storage tank is closed, otherwise, the regulating valve (105) of the supplementary heat steam of the urea solution pipeline of the storage tank is opened, and the temperature requirement of the urea solution pipeline (14) of the storage tank is met by adjusting the opening degree of the regulating valve (105) of the supplementary heat steam of the urea solution pipeline of the storage tank; the steam output by the steam ejector (20) enters the spray desuperheater (19) through the regulating valve (104) of the outlet steam pipeline of the steam ejector, and then enters the heating steam pipeline of the urea hydrolysis reactor (12) after being desuperheated by spraying water in the spray desuperheater (19). Under the operation mode of medium load in the power plant, the regulating valve (103) of the extraction steam pipeline of the fourth-stage steam turbine is opened, and the flow rate of the extracted steam is controlled by adjusting the opening degree of the regulating valve (103) of the extraction steam pipeline of the fourth-stage steam turbine; at this time, the steam ejector (20) stops working, the regulating valve (101) of the high-pressure steam pipeline of the steam ejector, the regulating valve (104) of the outlet steam pipeline of the steam ejector, and the regulating valve (106) of the entrained steam of the steam ejector are all in the closed state, and the regulating valve (102) of the extraction steam pipeline of the third-stage steam turbine is closed; when the temperature in the urea solution pipeline (14) of the storage tank meets the heat preservation temperature, the regulating valve (105) of the supplementary heat steam of the urea solution pipeline of the storage tank is closed, otherwise, the regulating valve (105) of the supplementary heat steam of the urea solution pipeline of the storage tank is opened, and the temperature requirement of the urea solution pipeline (14) of the storage tank is met by adjusting the opening degree of the regulating valve (105) of the supplementary heat steam of the urea solution pipeline of the storage tank. The steam output by the regulating valve (103) of the extraction steam pipeline of the fourth-stage steam turbine enters the spray desuperheater (19), and then enters the heating steam pipeline of the urea hydrolysis reactor (12) after being desuperheated by spraying water in the spray desuperheater (19). Under the operation mode of the power plant at low load, open the regulating valve (102) of the third-stage steam extraction pipeline of the steam turbine, and control the flow rate of the extracted steam through the opening degree of the regulating valve (102) of the third-stage steam extraction pipeline of the steam turbine; at this time, the steam ejector (20) stops working, and the regulating valves of the high-pressure steam pipeline (101), the outlet steam pipeline (104) and the entrained steam regulating valve (106) of the steam ejector are all in the closed state, and the regulating valve (103) of the fourth-stage steam extraction pipeline of the steam turbine is closed; when the temperature in the urea solution pipeline (14) of the storage tank meets the insulation temperature, the supplementary heat steam regulating valve (105) of the urea solution pipeline of the storage tank is closed, otherwise, open the supplementary heat steam regulating valve (105) of the urea solution pipeline of the storage tank, and adjust the opening degree of the supplementary heat steam regulating valve (105) of the urea solution pipeline of the storage tank to meet the temperature requirements of the urea solution pipeline (14) of the storage tank. The steam output by the regulating valve (102) of the third-stage steam extraction pipeline of the steam turbine enters the desuperheater (19), and then is sent to the heating steam pipeline of the urea hydrolysis reactor (12) after desuperheating by spraying water.

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