阅读说明：本技术 一种节能型尿素水解系统蒸汽减温减压装置 (Energy-saving urea system steam temperature and pressure reduction device that hydrolysises ) 是由 徐晓涛 潘栋 罗志 董陈 杨世极 舒凯 李淑宏 尚桐 袁壮 杨晓刚 石磊 张向 于 2021-10-21 设计创作，主要内容包括：本发明提供一种节能型尿素水解系统蒸汽减温减压装置,能够实现尿素水解系统的热量循环,回收高温高压蒸汽热量并加以二次利用,形成节能型循环回路,简化系统设备的布置同时提高运行经济性,降低改造成本,提高减温减压的质量。包括换热器,其上设置有蒸汽进口、蒸汽出口、稀释风进口和稀释风出口；所述蒸汽进口通过高温蒸汽管路与提供高温蒸汽的气源连接,高温蒸汽管路上设置调压阀；所述稀释风进口通过冷稀释风管路与提供冷稀释风的风源连接,冷稀释风管路上设有流量调节阀和流量计,所述蒸汽减温减压装置设置在所述尿素水解反应器和所述烟气换热器之间。(The invention provides a steam temperature and pressure reducing device of an energy-saving urea hydrolysis system, which can realize heat circulation of the urea hydrolysis system, recover high-temperature and high-pressure steam heat and reutilize the high-temperature and high-pressure steam heat to form an energy-saving circulation loop, simplify the arrangement of system equipment, improve the operation economy, reduce the modification cost and improve the quality of temperature and pressure reduction. Comprises a heat exchanger, a steam inlet, a steam outlet, a dilution air inlet and a dilution air outlet are arranged on the heat exchanger; the steam inlet is connected with an air source for providing high-temperature steam through a high-temperature steam pipeline, and a pressure regulating valve is arranged on the high-temperature steam pipeline; the dilution air inlet is connected with an air source for providing cold dilution air through a cold dilution air pipeline, a flow regulating valve and a flow meter are arranged on the cold dilution air pipeline, and the steam temperature and pressure reducing device is arranged between the urea hydrolysis reactor and the flue gas heat exchanger.)

1. An energy-saving urea hydrolysis system steam temperature and pressure reduction device is characterized by comprising

The heat exchanger (1) is provided with a steam inlet (11), a steam outlet (12), a dilution air inlet (13) and a dilution air outlet (14);

the steam inlet (11) is connected with an air source for providing high-temperature steam through a high-temperature steam pipeline, and the high-temperature steam pipeline is provided with a pressure regulating valve (2);

the dilution air inlet (13) is connected with an air source for providing cold dilution air through a cold dilution air pipeline, and a flow regulating valve (3) and a flow meter (4) are arranged on the cold dilution air pipeline.

2. The steam temperature and pressure reduction device of the energy-saving urea hydrolysis system as claimed in claim 1, wherein the heat exchanger (1) is one of a steam air heater, a hybrid heat exchanger or a shell-and-tube heat exchanger.

3. The steam temperature and pressure reduction device of the energy-saving urea hydrolysis system according to claim 1, wherein a manual ball valve (7), a pressure measuring device and a first temperature measuring element are further arranged on the high-temperature steam pipeline.

4. The steam temperature and pressure reducing device of the energy-saving urea hydrolysis system as claimed in claim 3, wherein the pressure regulating valve (2) is a double-seat pressure reducing valve structure.

5. An energy-saving type urea hydrolysis system steam temperature and pressure reduction device according to claim 3, characterized in that a safety valve is arranged between the pressure regulating valve (2) and the manual ball valve (7).

6. The steam temperature and pressure reduction device of the energy-saving urea hydrolysis system as claimed in claim 1, wherein a plurality of stop valves are further disposed on the cold dilution air pipeline.

7. The steam temperature and pressure reduction device of the energy-saving urea hydrolysis system as claimed in claim 1, wherein a second temperature measuring element is arranged at the steam outlet (12).

8. An energy-saving urea hydrolysis system, which is characterized by comprising a steam temperature and pressure reduction device, a urea hydrolysis reactor (5) and a flue gas heat exchanger (6) according to any one of claims 1 to 7, wherein the steam temperature and pressure reduction device is arranged between the urea hydrolysis reactor (5) and the flue gas heat exchanger (6);

the system comprises a urea hydrolysis reactor (5), a steam outlet (12) of a heat exchanger (1), a dilution air outlet (14) of the heat exchanger (1), a flue gas heat exchanger (6), and an ammonia-air mixer (15), wherein the steam outlet (12) of the heat exchanger (1) is connected with a reaction inlet of the urea hydrolysis reactor (5), the dilution air outlet (14) of the heat exchanger (1) is connected with an inlet of the flue gas heat exchanger (6), and the reaction outlet of the urea hydrolysis reactor (5) and the outlet of the flue gas heat exchanger (6) are respectively connected with inlets of ammonia-air mixers (15) in a denitration area.

9. An energy-saving urea hydrolysis system according to claim 8, wherein a check valve (10) is arranged on the pipeline between the dilution air outlet (14) and the flue gas heat exchanger (6).

Technical Field

The invention belongs to the technical field of urea hydrolysis systems, and particularly relates to a steam temperature and pressure reducing device of an energy-saving urea hydrolysis system.

Background

The urea hydrolysis ammonia preparation is a mature denitration reducing agent preparation process, and many thermal power generating units at home and abroad are improved by the urea hydrolysis process instead of the liquid ammonia process.

The principle of the urea hydrolysis reaction is that urea solution with the mass concentration of about 50 percent is injected into a hydrolysis reactor and is heated to a certain temperature and pressure to generate NH through hydrolysis reaction₃、CO₂And water vapor is fed into an ammonia-air mixer in the denitration area to be mixed with hot dilution air, and then the mixture is fed into a denitration reactor, wherein the hot dilution air is generally obtained by heating cold dilution air by using a flue gas heat exchanger arranged in a denitration outlet flue. The heating steam of the hydrolysis reactor is designed to have the temperature of 180 ℃ and the pressure of 1MP, the heating steam is prepared by a temperature and pressure reducing device, an air source is taken from the common auxiliary steam of a plant area or the cold re-extraction of a unit, and the steam is obtainedThe steam temperature is generally higher than 300 ℃ and the pressure is more than 1 MPa.

The temperature and pressure reducing device commonly used at present mainly comprises a pressure reducing valve, a temperature reducing water pump and a temperature reducing water nozzle. The pressure of the high-temperature high-pressure steam is adjusted to be near 1MPa after passing through the pressure reduction adjusting valve, then a large amount of temperature reduction water is sprayed through the temperature reduction water nozzle to reduce the temperature of the high-temperature steam to 180 ℃, and finally the high-temperature high-pressure steam enters the hydrolysis reactor. Therefore, above-mentioned steam temperature and pressure reduction process energy loss is big, and need additionally set up corresponding attemperator and cool down steam, can waste a large amount of attemperators when cooling, has improved holistic running cost when increasing the system complexity, moreover, still need be equipped with corresponding waste water treatment device and carry out secondary treatment to attemperator, cooling efficiency and effect are also not fully satisfactory, influence unit operation economic nature.

In addition, as described above, after the urea hydrolysis reaction, the product generated after the urea hydrolysis reaction needs to be mixed with hot dilution air to denitrate in the denitration area, so that a flue gas heat exchanger needs to be arranged in the urea hydrolysis system to heat cold dilution air firstly to obtain hot dilution air, and then the hot dilution air is mixed with the product, when the usage amount of the used hot dilution air is large, the flue gas heat exchanger with a large heat exchange area needs to be correspondingly arranged to heat to obtain the required hot dilution air, the difficulty of how to arrange the overlarge heat exchanger is increased, and the difficulty of arranging the urea hydrolysis system is increased.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides the energy-saving urea hydrolysis system steam temperature and pressure reduction device, which can realize the heat circulation of the urea hydrolysis system, recover the heat of high-temperature and high-pressure steam and reutilize the heat to form an energy-saving circulation loop, simplify the arrangement of system equipment, improve the operation economy, reduce the reconstruction cost and improve the quality of temperature and pressure reduction.

The invention is realized by the following technical scheme:

an energy-saving urea hydrolysis system steam temperature and pressure reduction device comprises

The heat exchanger is provided with a steam inlet, a steam outlet, a dilution air inlet and a dilution air outlet;

the steam inlet is connected with an air source for providing high-temperature steam through a high-temperature steam pipeline, and a pressure regulating valve is arranged on the high-temperature steam pipeline;

the dilution air inlet is connected with an air source for providing cold dilution air through a cold dilution air pipeline, and a flow regulating valve and a flow meter are arranged on the cold dilution air pipeline.

Preferably, the heat exchanger adopts one of a steam air heater, a hybrid heat exchanger or a shell-and-tube heat exchanger.

Preferably, a manual ball valve, a pressure measuring device and a first temperature measuring element are further arranged on the high-temperature steam pipeline.

Preferably, the pressure regulating valve adopts a double-valve-seat pressure reducing valve structure.

Preferably, a safety valve is arranged between the pressure regulating valve and the manual ball valve.

Preferably, the safety valve is an impulse type safety valve.

Preferably, a plurality of stop valves are further arranged on the cold dilution air pipeline.

Preferably, a second temperature measuring element is arranged at the steam outlet.

An energy-saving urea hydrolysis system comprises the steam temperature and pressure reduction device, the urea hydrolysis reactor and the flue gas heat exchanger, wherein the steam temperature and pressure reduction device is arranged between the urea hydrolysis reactor and the flue gas heat exchanger;

the steam outlet of the heat exchanger is connected with the reaction inlet of the urea hydrolysis reactor, the dilution air outlet of the heat exchanger is connected with the inlet of the flue gas heat exchanger, and the reaction outlet of the urea hydrolysis reactor and the outlet of the flue gas heat exchanger are respectively connected with the inlet of an ammonia air mixer of the denitration area.

Preferably, a check valve is arranged on a pipeline between the dilution air outlet and the flue gas heat exchanger.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention provides a steam temperature and pressure reduction device of an energy-saving urea hydrolysis system, which is characterized in that a set of heat exchanger is added in an original urea hydrolysis system, 4 connectors are arranged on the heat exchanger and comprise a steam inlet and a dilution air inlet, a pressure regulating valve is arranged in front of the steam inlet, high-temperature and high-pressure steam introduced by an air source is subjected to pressure regulating operation, the high-temperature and high-pressure steam is introduced into the heat exchanger after being regulated to proper pressure, part of cold dilution air is introduced to be mixed with the high-temperature steam for heat exchange, a flow regulating valve and a flow meter are arranged in front of the dilution air inlet, and the temperature of the steam at the steam outlet is controlled by regulating the flow of the cold dilution air entering the heat exchanger, so that the purpose of recovering the heat of the high-temperature and high-pressure steam is achieved, and the running economy of a unit is improved; in addition, the dilution air outlet of the heat exchanger is connected with the flue gas heat exchanger at the outlet of the denitration flue, and part of cold dilution air is heated into hot dilution air in the heat exchanger, so that the hot dilution air can directly participate in the subsequent mixing with hydrolysis products, the heat exchange area of the flue gas heat exchanger at the outlet of the SCR can be greatly reduced, the purchase cost of the heat exchanger is reduced, the transformation cost is saved, the heat circulation of a urea hydrolysis system is realized, and the heat of recovered high-temperature high-pressure steam is secondarily utilized to form an energy-saving circulation loop.

Drawings

FIG. 1 is a schematic view of a steam temperature and pressure reducing device according to the present invention;

FIG. 2 is a schematic diagram of the energy-saving urea hydrolysis system of the present invention.

In the figure: the device comprises a heat exchanger 1, a steam inlet 11, a steam outlet 12, a dilution air inlet 13, a dilution air outlet 14, a pressure regulating valve 2, a flow regulating valve 3, a flowmeter 4, a urea hydrolysis reactor 5, a flue gas heat exchanger 6, a manual ball valve 7, a pressure transmitter 8, a temperature transmitter 9, a check valve 10 and an ammonia-air mixer 15.

Detailed Description

The present invention will now be described in further detail with reference to the attached drawings, which are illustrative, but not limiting, of the present invention.

The invention relates to a steam temperature and pressure reducing device of an energy-saving urea hydrolysis system, which comprises,

the heat exchanger 1 is provided with a steam inlet 11, a steam outlet 12, a dilution air inlet 13 and a dilution air outlet 14;

the steam inlet 11 is connected with an air source for providing high-temperature steam through a high-temperature steam pipeline, and the high-temperature steam pipeline is provided with a pressure regulating valve 2;

the dilution air inlet 13 is connected with an air source for providing cold dilution air through a cold dilution air pipeline, and a flow regulating valve 3 and a flow meter 4 are arranged on the cold dilution air pipeline.

The invention provides a steam temperature and pressure reduction device of an energy-saving urea hydrolysis system, which is characterized in that a set of heat exchanger 1 is added in an original urea hydrolysis system, 4 connectors are arranged on the heat exchanger 1, the heat exchanger comprises a steam inlet and a dilution air inlet, a pressure regulating valve 2 is arranged in front of a steam inlet 11, high-temperature and high-pressure steam introduced from an air source is subjected to pressure regulating operation, the high-temperature and high-pressure steam is regulated to proper pressure and then enters the heat exchanger 1, partial cold dilution air is introduced to be subjected to mixed heat exchange with the high-temperature steam, a flow regulating valve 3 and a flow meter 4 are arranged in front of a dilution air inlet 13, and the temperature of the steam at a steam outlet 12 is controlled by regulating the flow of the cold dilution air entering the heat exchanger 1, so that the purpose of recovering the heat of the high-temperature and high-pressure steam is achieved, and the running economy of a unit is improved; in addition, the dilution air outlet 14 of the heat exchanger 1 is connected with the flue gas heat exchanger 6 at the outlet of the denitration flue, and part of cold dilution air is heated into hot dilution air in the heat exchanger 1, so that the hot dilution air can directly participate in the subsequent mixing with hydrolysis products, the heat exchange area of the flue gas heat exchanger 6 at the outlet of the SCR can be greatly reduced, the purchase cost of the heat exchanger is reduced, the transformation cost is saved, the heat circulation of a urea hydrolysis system is realized, the heat of the recovered high-temperature high-pressure steam is secondarily utilized, and an energy-saving circulation loop is formed.

In this embodiment, the heat exchanger 1 is one of a steam air heater, a hybrid heat exchanger and a shell-and-tube heat exchanger, and a criss-cross serpentine tube is arranged inside the heat exchanger 1, so that the heat exchange area can be increased in a limited space, wherein a steam inlet 11 and a steam outlet 12 are connected with a heat source tube inside the heat exchanger 1, and a dilution air inlet 13 and a dilution air outlet 14 are connected with a cold source tube inside the heat exchanger 1; or the hot fluid and the cold fluid are directly contacted with each other in the heat exchanger for heat exchange.

In this embodiment, the high-temperature steam pipeline is further provided with a plurality of manual ball valves 7, a pressure measuring device and a first temperature measuring element.

Preferably, the pressure regulating valve 2 adopts a double-seat pressure reducing valve structure.

Preferably, a safety valve is arranged between the pressure regulating valve 2 and the second manual ball valve on the pipeline.

Preferably, the safety valve is an impulse type safety valve.

Preferably, the pressure measuring device employs a pressure transducer 8.

Preferably, the first temperature measuring element employs a temperature transmitter 9.

In this embodiment, still be provided with a plurality of stop valves on the cold dilution air pipeline.

In this embodiment, a second temperature measuring element is disposed at the steam outlet 12.

Preferably, the second temperature measuring element employs a temperature transmitter 9.

The invention also provides an energy-saving urea hydrolysis system, which comprises the steam temperature and pressure reduction device, a urea hydrolysis reactor 5 and a flue gas heat exchanger 6, wherein the steam temperature and pressure reduction device is arranged between the urea hydrolysis reactor 5 and the flue gas heat exchanger 6;

the steam outlet 12 of the heat exchanger 1 is connected with the reaction inlet of the urea hydrolysis reactor 5, the dilution air outlet 14 of the heat exchanger 1 is connected with the inlet of the flue gas heat exchanger 6, and the reaction outlet of the urea hydrolysis reactor 5 and the outlet of the flue gas heat exchanger 6 are respectively connected with the inlet of an ammonia air mixer 15 of the denitration area.

In this embodiment, a check valve 10 is disposed on a pipeline between the dilution air outlet 14 and the flue gas heat exchanger 6.

The invention provides an energy-saving urea hydrolysis system, which is operated as follows when in use:

high-temperature and high-pressure steam enters the heat exchanger 1 from the steam inlet 11 after passing through the pressure regulating valve 2;

cold dilution air enters the heat exchanger 1 from a dilution air inlet 13 after passing through the flow regulating valve 3 and the flow meter 4;

the high-temperature steam subjected to pressure regulation and cold dilution air exchange heat in a heat exchanger 1;

the temperature and the pressure of the steam after heat exchange are reduced to the proper hydrolysis temperature of the urea solution, and the urea solution is sent to a urea area;

after being heated, the cold dilution air is converged with the rest cold dilution air, enters the denitration outlet flue gas heat exchanger 6, is heated again, then enters the ammonia air mixer 15 of the denitration area, and is mixed with a product of urea hydrolysis.

In the invention, because the temperature of heating steam designed by the urea hydrolyzer is 180 ℃, the pressure is 1MP, the steam pressure is mainly controlled by the pressure regulating valve 2, in order to control the temperature of the steam at the outlet of the steam air heater, a flow regulating valve 3 and a flow meter 4 are arranged in a pipeline before cold dilution air enters the steam air heater, the pressure and temperature parameters of the steam at the outlet of the steam air heater are controlled by regulating the flow of the cold dilution air entering the steam air heater and coupling the action of the pressure regulating valve 2, the parameter requirements of the heating steam of the urea hydrolyzation system can be always met, the stability of the urea hydrolysis reaction is ensured, and the ammonia reducing agent is continuously prepared.

The foregoing embodiments and description are merely illustrative of the principles of the invention, and various changes and modifications can be made therein without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed.