Circulating water liquid ammonia evaporation system

Abstract

The utility model discloses a circulating water liquid ammonia evaporation system, and belongs to the technical field of thermal power plants. The system comprises a high-position buffer tank, a liquid ammonia evaporator, an indirect cooling tower and an air condenser, the high-position buffer tank is used for feeding ammonia gas evaporated by the liquid ammonia evaporator into the stokehole ammonia doping system; and the liquid ammonia evaporator is used for evaporating liquid ammonia in a liquid ammonia pipeline into ammonia gas by utilizing waste heat of circulating water between the indirect cooling tower and the air-cooled condenser. The circulating water waste heat is used as a heat source to evaporate and overheat the liquid ammonia, the circulating water waste heat is recycled, and the loss of steam or electric energy caused by liquid ammonia evaporation is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of thermal power plants, in particular to a circulating water liquid ammonia evaporation system. Background Art

[0002] Thermal power plants use ammonia blending as a means of reducing carbon emissions. However, the transportation and use of liquid ammonia hides a significant energy waste problem. Liquid ammonia must be evaporated and gasified before entering the boiler for combustion. Currently, most thermal power plants use steam as the heat source for evaporating liquid ammonia. The source of steam is usually high-temperature and high-pressure steam from the boiler. This steam was originally used to drive the steam turbine to generate electricity, but after being used for evaporating liquid ammonia, its latent heat is consumed in large quantities, resulting in reduced energy utilization efficiency.

[0003] In addition to steam heat source, some thermal power plants also use electricity as the heat source for liquid ammonia evaporation. Although this method avoids the direct consumption of steam, the production process of electricity is also accompanied by energy loss and increased emissions. Especially when the amount of ammonia blended increases, the amount of steam and electricity required will increase accordingly, resulting in greater energy loss. Utility Model Content

[0004] Aiming at the problem of excessive loss of steam or electric energy in the evaporation of liquid ammonia in the prior art, the utility model provides a circulating water liquid ammonia evaporation system, which uses the waste heat of circulating water as a heat source to evaporate and superheat the liquid ammonia, recovers the waste heat of circulating water, and reduces the loss of steam or electric energy in the evaporation of liquid ammonia.

[0005] In order to achieve the above-mentioned purpose, the utility model provides the following technical solutions.

[0006] A circulating water liquid ammonia evaporation system comprises a high-level buffer, a liquid ammonia evaporator, an intercooling tower and an air-cooled condenser; the high-level buffer is used to send the ammonia gas evaporated by the liquid ammonia evaporator into a pre-furnace ammonia blending system; the liquid ammonia evaporator is used to utilize the waste heat of the circulating water between the intercooling tower and the air-cooled condenser to evaporate the liquid ammonia in the liquid ammonia pipeline into ammonia gas.

[0007] Optionally, the water inlet end of the liquid ammonia evaporator is connected to the hot water main pipe between the intercooling tower and the air-to-air condenser; the water outlet end of the liquid ammonia evaporator is connected to the cold water main pipe between the intercooling tower and the air-to-air condenser.

[0008] Optionally, a first regulating valve is provided between the water inlet end of the liquid ammonia evaporator and the hot water main pipe; a first temperature transmitter is provided between the water inlet end of the liquid ammonia evaporator and the first regulating valve; and a first check valve is provided between the first regulating valve and the hot water main pipe.

[0009] Optionally, a second check valve, a third check valve and a starting pump are also provided between the first regulating valve and the hot water main pipe; one end of the second check valve is connected between the first regulating valve and the first check valve, the other end of the second check valve is connected to one end of the third check valve, and the other end of the third check valve is connected between the first check valve and the hot water main pipe; the starting pump is installed between the second check valve and the third check valve.

[0010] Optionally, a second temperature transmitter is provided between the water outlet of the liquid ammonia evaporator and the cooling water main pipe; and a circulating water pump is provided on the cooling water main pipe between the water outlet of the liquid ammonia evaporator and the air-cooled condenser.

[0011] Optionally, the liquid ammonia evaporator is connected to the hot water main pipe between the intercooling tower and the air-cooling condenser; the water inlet end of the liquid ammonia evaporator is close to the hot water main pipe in the direction of the air-cooling condenser, and the water outlet end of the liquid ammonia evaporator is close to the hot water main pipe in the direction of the intercooling tower; a second regulating valve is provided on the hot water main pipe between the intercooling tower and the air-cooling condenser.

[0012] Optionally, a first temperature transmitter is provided between the water inlet end of the liquid ammonia evaporator and the hot water main pipe, and a first check valve is provided between the first temperature transmitter and the hot water main pipe; a second temperature transmitter is provided between the water outlet end of the liquid ammonia evaporator and the hot water main pipe.

[0013] Optionally, a circulating water pump is provided on the cooling water main pipe between the intercooling tower and the air-cooled condenser.

[0014] Optionally, the lower part of the liquid ammonia evaporator is connected to the liquid ammonia pipeline, and the upper part of the liquid ammonia evaporator is connected to the upper middle part of the high-level buffer; the lower part of the high-level buffer is connected to the lower part of the liquid ammonia evaporator.

[0015] Optionally, the upper part of the high-level buffer is connected to a pre-furnace ammonia doping system.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] The utility model provides a circulating water liquid ammonia evaporation system, which uses the circulating water waste heat between the intercooler and the air-cooled condenser as a heat source to provide heat energy for the liquid ammonia evaporator, not only recovering the waste heat that might have been lost, but also reducing the dependence on steam or electric energy during the evaporation of liquid ammonia. Thereby reducing production costs and reducing waste heat emissions. In the liquid ammonia evaporator, the waste heat is heat-exchanged with liquid ammonia, so that the liquid ammonia is heated, evaporated and overheated, and converted into ammonia gas and transported to a high-level buffer. The ammonia gas is transported to the ammonia blending system in front of the furnace through the high-level buffer, and the liquid ammonia that has not been evaporated into ammonia gas will be re-evaporated through the liquid ammonia evaporator. Therefore, the utility model effectively utilizes the waste heat that was originally wasted, provides the required heat energy for the evaporation of liquid ammonia, and reduces the loss of steam or electric energy during the evaporation of liquid ammonia. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are for explanation purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only for illustration purposes to help understand the present invention and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings:

[0019] Figure 1 This is a schematic diagram of a circulating water-liquid ammonia evaporation system according to Example 1 of the utility model;

[0020] Figure 2 This is a schematic diagram of a circulating water-liquid ammonia evaporation system according to Example 2 of the utility model.

[0021] In the figure, 1 is a high-level buffer; 2 is a liquid ammonia evaporator; 21 is a safety valve; 3 is an intercooler; 4 is an air-cooled condenser; 5 is a circulating water pump; 61 is a hot water main pipe; 62 is a cold water main pipe; 7 is a first temperature transmitter; 8 is a second temperature transmitter; 9 is a third temperature transmitter; 101 is a first regulating valve; 102 is a first check valve; 103 is a second check valve; 104 is a third check valve; 105 is a starting pump; 106 is a second regulating valve; 11 is a fourth temperature transmitter; 12 is a pressure transmitter; 13 is a pre-furnace ammonia blending system; and 14 is a liquid ammonia pipeline. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0025] The utility model discloses a circulating water liquid ammonia evaporation system, which comprises a high-position buffer 1, a liquid ammonia evaporation unit, an intercooler 3 and an air-cooled condenser 4.

[0026] The liquid ammonia evaporation unit comprises a liquid ammonia evaporator 2 .

[0027] The intercooling tower 3 and the air-cooled condenser 4 are connected by an intercooling circulating water pipe, the liquid ammonia evaporator 2 is connected to the intercooling circulating water pipe, and the high-level buffer 1 is connected to the liquid ammonia evaporator 2. The liquid ammonia in the liquid ammonia pipeline 14 enters the liquid ammonia evaporator 2 from the bottom of the liquid ammonia evaporator 2. Most of the liquid ammonia is evaporated after heat exchange in the liquid ammonia evaporator 2. After evaporation, the liquid ammonia becomes ammonia gas and enters the high-level buffer 1 from the middle of the high-level buffer 1. A small amount of liquid ammonia that has not been evaporated flows back to the liquid ammonia evaporator 2 from the bottom pipeline of the high-level buffer 1, and is evaporated again through the liquid ammonia evaporator 2. The ammonia gas in the high-level buffer 1 enters the pre-furnace ammonia mixing system 13 through the top outlet of the high-level buffer 1.

[0028] like Figure 1 As shown, the intercooling tower 3 and the air-cooling condenser 4 are provided with an intercooling circulating water pipe, and the intercooling circulating water pipe includes a hot water pipe 61 and a cold water pipe 62 .

[0029] The circulating water in the intercooling tower 3 enters the air-cooled condenser 4 through the cold water main pipe 62. In the air-cooled condenser 4, the circulating water exchanges heat with the exhaust steam of the steam turbine, absorbs the heat in the exhaust steam and transfers it to the circulating water, so that the exhaust steam is condensed into water. The temperature of the circulating water after the heat exchange increases, and it enters the intercooling tower 3 again through the hot water main pipe 61 for cooling and recycling. Therefore, the circulating water in the intercooling tower 3 will enter the air-cooled condenser 4, playing a role in cooling the exhaust steam of the steam turbine. Such a cycle process can be carried out continuously to ensure the effective condensation of the exhaust steam of the steam turbine and the normal operation of the system.

[0030] The water inlet end of the liquid ammonia evaporator 2 is connected to the hot water main pipe 61 , and the water outlet end of the liquid ammonia evaporator 2 is connected to the cold water main pipe 62 .

[0031] A first regulating valve 101 is provided on the main road between the water inlet end of the liquid ammonia evaporator 2 and the hot water main pipe 61, a first check valve 102 is provided between the first regulating valve 101 and the hot water main pipe 61, one end of the second check valve 103 is connected between the first regulating valve 101 and the first check valve 102, the other end of the second check valve 103 is connected to the start pump 105, the start pump 105 is also connected to one end of the third check valve 104, the other end of the third check valve 104 is connected between the first check valve 102 and the hot water main pipe 61, the second check valve 103, the third check valve 104 and the start pump 105 are provided on the bypass road between the water inlet end of the liquid ammonia evaporator 2 and the hot water main pipe 61. A first temperature transmitter 7 is provided between the water inlet end of the liquid ammonia evaporator 2 and the first regulating valve 101. A second temperature transmitter 8 is provided between the water outlet end of the liquid ammonia evaporator 2 and the cold water main pipe 62. A circulating water pump 5 is provided on the cooling water main pipe 62 between the water outlet of the liquid ammonia evaporator 2 and the air-cooled condenser 4. The circulating water pump 5 ensures that the circulating water circulates between the intercooler 3 and the air-cooled condenser according to a set flow rate.

[0032] A first regulating valve 101 is provided on the main circuit of the water inlet end of the liquid ammonia evaporator 2, and the first regulating valve 101 is used to regulate the amount of circulating water passing through the liquid ammonia evaporator 2 to maintain the temperature stability at the outlet end of the liquid ammonia evaporator 2. A starting pump 105 is provided on the bypass circuit of the water inlet end of the liquid ammonia evaporator 2. When the circulating water pressure in the hot water main pipe 61 is low, the first check valve 102 is closed, and the starting pump 105 in the bypass circuit is started to ensure the stable supply of circulating water in the liquid ammonia evaporator 2. A temperature transmitter is provided at both the water inlet end and the water outlet end of the liquid ammonia evaporator 2, and the temperature of the liquid ammonia evaporator 2 is measured by the temperature transmitter, and the temperature of the liquid ammonia evaporator 2 is controlled according to the measured temperature.

[0033] The lower part of the liquid ammonia evaporator 2 is connected to the liquid ammonia pipeline 14. After the liquid ammonia in the liquid ammonia pipeline 14 enters the liquid ammonia evaporator 2, most of the liquid ammonia is evaporated after heat exchange in the liquid ammonia evaporator 2. After the liquid ammonia evaporates, it becomes ammonia gas and enters the high buffer 1 from the middle part of the high buffer 1. The middle part of the high buffer 1 is connected to the upper area of ​​the liquid ammonia evaporator 2. The middle inlet of the high buffer 1 is provided with a fourth temperature transmitter 11 and a pressure transmitter 12, wherein the fourth temperature transmitter 11 is close to the middle inlet of the high buffer 1, and the pressure transmitter 12 is far away from the middle inlet of the high buffer 1. The upper area of ​​the liquid ammonia evaporator 2 is provided with a safety valve 21. A small amount of liquid ammonia that has not been evaporated flows back to the liquid ammonia evaporator 2 from the bottom pipeline of the high buffer 1, and the liquid ammonia is evaporated again through the liquid ammonia evaporator 2. The ammonia gas in the high buffer 1 enters the pre-furnace ammonia mixing system 13 through the top outlet of the high buffer 1. A third temperature transmitter 9 is provided between the lower part of the liquid ammonia evaporator 2 and the liquid ammonia pipeline 14 .

[0034] like Figure 2As shown, the intercooling tower 3 and the air-cooling condenser 4 are provided with an intercooling circulating water pipe, and the intercooling circulating water pipe includes a hot water pipe 61 and a cold water pipe 62 .

[0035] The circulating water in the intercooling tower 3 enters the air-cooled condenser 4 through the cold water main pipe 62. In the air-cooled condenser 4, the circulating water exchanges heat with the exhaust steam of the steam turbine, absorbs the heat in the exhaust steam and transfers it to the circulating water, so that the exhaust steam is condensed into water. The temperature of the circulating water after the heat exchange increases, and it enters the intercooling tower 3 again through the hot water main pipe 61 for cooling and recycling. Therefore, the circulating water in the intercooling tower 3 will enter the air-cooled condenser 4, playing a role in cooling the exhaust steam of the steam turbine. Such a cycle process can be carried out continuously to ensure the effective condensation of the exhaust steam of the steam turbine and the normal operation of the system.

[0036] The liquid ammonia evaporator 2 is arranged on the hot water main pipe 61, wherein the water inlet end of the liquid ammonia evaporator 2 is connected to the hot water main pipe 61 close to the intercooler 3, and the water outlet end of the liquid ammonia evaporator 2 is connected to the hot water main pipe 61 close to the air-cooled condenser 4.

[0037] A first check valve 102 is provided between the water inlet of the liquid ammonia evaporator 2 and the hot water main pipe 61, and a first temperature transmitter 7 is provided between the water inlet of the liquid ammonia evaporator 2 and the first check valve 102. A second temperature transmitter 8 is provided between the water outlet of the liquid ammonia evaporator 2 and the hot water main pipe 61. A second regulating valve 106 is provided on the hot water main pipe 61 between the water inlet and the water outlet of the liquid ammonia evaporator 2. A circulating water pump 5 is provided on the cold water main pipe 62 between the water inlet of the liquid ammonia evaporator 2 and the intercooler 3.

[0038] The lower part of the liquid ammonia evaporator 2 is connected to the liquid ammonia pipeline 14. After the liquid ammonia in the liquid ammonia pipeline 14 enters the liquid ammonia evaporator 2, most of the liquid ammonia is evaporated after heat exchange in the liquid ammonia evaporator 2. After the liquid ammonia evaporates, it becomes ammonia gas and enters the high buffer 1 from the middle part of the high buffer 1. The middle part of the high buffer 1 is connected to the upper area of ​​the liquid ammonia evaporator 2. The middle inlet of the high buffer 1 is provided with a fourth temperature transmitter 11 and a pressure transmitter 12, wherein the fourth temperature transmitter 11 is close to the middle inlet of the high buffer 1, and the pressure transmitter 12 is far away from the middle inlet of the high buffer 1. The upper area of ​​the liquid ammonia evaporator 2 is provided with a safety valve 21. A small amount of liquid ammonia that has not been evaporated flows back to the liquid ammonia evaporator 2 from the bottom pipeline of the high buffer 1, and the liquid ammonia is evaporated again through the liquid ammonia evaporator 2. The ammonia gas in the high buffer 1 enters the pre-furnace ammonia mixing system 13 through the top outlet of the high buffer 1. A third temperature transmitter 9 is provided between the lower part of the liquid ammonia evaporator 2 and the liquid ammonia pipeline 14 .

[0039] The liquid ammonia in the liquid ammonia pipeline 14 comes from the liquid ammonia in the ammonia tank or the liquid ammonia pump.

[0040] In summary, both the intercooler and the air-cooled condenser will generate a certain amount of circulating water waste heat. If these waste heats are directly discharged into the environment, it will not only cause energy waste, but also may cause thermal pollution to the environment. By using this part of waste heat as a heat source and supplying it to the liquid ammonia evaporator, the effective utilization of waste heat can be achieved. The liquid ammonia evaporator is responsible for evaporating and superheating the liquid ammonia. However, the traditional liquid ammonia evaporation process usually consumes a large amount of steam or electricity, which not only increases the operating cost, but also may cause a certain burden on the environment. Using the circulating water waste heat as a heat source can significantly reduce the dependence of liquid ammonia evaporation on steam or electricity, thereby reducing energy consumption and environmental pollution. Therefore, the utility model provides a circulating water liquid ammonia evaporation system, which guides the circulating water waste heat of the intercooler and the air-cooled condenser to the liquid ammonia evaporator through a pipeline system, and through the liquid ammonia evaporator, the waste heat in the circulating water is heat-exchanged with liquid ammonia, so that the liquid ammonia is heated and evaporated and superheated. In this way, the waste heat that was originally wasted is effectively utilized to provide the required heat energy for liquid ammonia evaporation. The utility model not only recovers the waste heat that might be lost, but also reduces the loss of steam or electric energy caused by the evaporation of liquid ammonia, thereby improving the energy utilization efficiency of the entire power generation system.

[0041] Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the preceding claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed utility model subject matter.

[0042] The above content is a further detailed description of the utility model. It cannot be determined that the specific implementation methods of the utility model are limited to these. For ordinary technicians in the technical field to which the utility model belongs, they can make some simple deductions or substitutions without departing from the concept of the utility model, which should be regarded as belonging to the protection scope of the utility model determined by the submitted claims.

Claims

1. A circulating water liquid ammonia evaporation system, characterized in that: It comprises a high-level buffer (1), a liquid ammonia evaporator (2), an intercooler (3) and an air-cooled condenser (4); The high-level buffer (1) is used to send the ammonia gas evaporated by the liquid ammonia evaporator (2) into the pre-furnace ammonia mixing system (13); The liquid ammonia evaporator (2) is used to utilize waste heat of circulating water between the intercooler (3) and the air-cooled condenser (4) to evaporate liquid ammonia in the liquid ammonia pipeline (14) into ammonia gas.

2. A circulating water liquid ammonia evaporation system according to claim 1, characterized in that: The water inlet end of the liquid ammonia evaporator (2) is connected to the hot water main pipe (61) between the intercooler (3) and the air-cooled condenser (4); The water outlet end of the liquid ammonia evaporator (2) is connected to the cooling water main pipe (62) between the intercooler (3) and the air-cooled condenser (4).

3. A circulating water liquid ammonia evaporation system according to claim 2, characterized in that: A first regulating valve (101) is provided between the water inlet end of the liquid ammonia evaporator (2) and the hot water main pipe (61); A first temperature transmitter (7) is provided between the water inlet end of the liquid ammonia evaporator (2) and the first regulating valve (101); A first check valve (102) is provided between the first regulating valve (101) and the hot water main pipe (61).

4. A circulating water liquid ammonia evaporation system according to claim 3, characterized in that: A second check valve (103), a third check valve (104) and a starter pump (105) are also provided between the first regulating valve (101) and the hot water main pipe (61); One end of the second check valve (103) is connected between the first regulating valve (101) and the first check valve (102), the other end of the second check valve (103) is connected to one end of the third check valve (104), and the other end of the third check valve (104) is connected between the first check valve (102) and the hot water main pipe (61); The priming pump (105) is installed between the second check valve (103) and the third check valve (104).

5. A circulating water liquid ammonia evaporation system according to claim 2, characterized in that: A second temperature transmitter (8) is provided between the water outlet of the liquid ammonia evaporator (2) and the cold water main pipe (62); A circulating water pump (5) is provided on the cooling water main pipe (62) between the water outlet of the liquid ammonia evaporator (2) and the air-cooled condenser (4).

6. A circulating water liquid ammonia evaporation system according to claim 1, characterized in that: The liquid ammonia evaporator (2) is connected to the hot water main pipe (61) between the intercooler (3) and the air-cooled condenser (4); The water inlet end of the liquid ammonia evaporator (2) is close to the hot water main pipe (61) in the direction of the air-cooled condenser (4), and the water outlet end of the liquid ammonia evaporator (2) is close to the hot water main pipe (61) in the direction of the intercooler (3); A second regulating valve (106) is provided on the hot water main pipe (61) between the intercooling tower (3) and the air-to-air condenser (4).

7. A circulating water liquid ammonia evaporation system according to claim 6, characterized in that: A first temperature transmitter (7) is provided between the water inlet end of the liquid ammonia evaporator (2) and the hot water main pipe (61), and a first check valve (102) is provided between the first temperature transmitter (7) and the hot water main pipe (61); A second temperature transmitter (8) is provided between the water outlet of the liquid ammonia evaporator (2) and the hot water main pipe (61).

8. A circulating water liquid ammonia evaporation system according to claim 6, characterized in that: A circulating water pump (5) is provided on the cooling water main pipe (62) between the intercooling tower (3) and the air-to-air condenser (4).

9. A circulating water liquid ammonia evaporation system according to claim 1, characterized in that: The lower part of the liquid ammonia evaporator (2) is connected to the liquid ammonia pipeline (14), and the upper part of the liquid ammonia evaporator (2) is connected to the middle and upper part of the high-level buffer (1); The lower part of the high-level buffer (1) is connected to the lower part of the liquid ammonia evaporator (2).

10. A circulating water liquid ammonia evaporation system according to claim 1, characterized in that: The upper part of the high-level buffer (1) is connected to the pre-furnace ammonia mixing system.

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