Static pressure energy recovery device for urea synthesis

Abstract

The utility model discloses a static pressure energy recycling device for urea synthesis, including stripping column, the top of stripping column is connected with liquid inlet pipeline, and the bottom of stripping column is connected with decomposition tower through liquid inlet pipeline, and the liquid inlet pipeline is installed with pressure -reducing valve and flowmeter, and the liquid inlet pipeline of pressure -reducing valve both sides is connected with bypass pipeline, and the bypass pipeline is installed with power generation device, the utility model discloses a bypass pipeline is set up at pressure -reducing valve, sets up water turbine and generator on bypass pipeline, can maximum limit recycling static pressure energy of methylamine solution between stripping column and decomposition tower, and power generation is driven through water turbine generator, supplies other electric equipment use, reduces the power consumption of static pressure energy recycling device for urea synthesis.

Description

Technical Field

[0001] This utility model belongs to the technical field of fertilizer production equipment, and relates to a static pressure energy recovery and utilization device for urea synthesis. Background Technology

[0002] Urea is one of the simplest organic compounds and a major nitrogen-containing end product of protein metabolism in mammals and some fish. It can be used as a fertilizer, animal feed, explosives, glue stabilizer, and chemical raw material. As a neutral fertilizer, urea is suitable for various soils and plants. It is easy to store, convenient to use, and has minimal impact on soil health. It is a widely used chemical nitrogen fertilizer in agriculture.

[0003] In industry, liquid ammonia and carbon dioxide are commonly used to synthesize urea via carbon dioxide stripping, a common method in fertilizer production. The high-pressure loop and decomposition process of the carbon dioxide stripping urea synthesis system includes a urea synthesis tower, stripping tower, ammonium carbamate condenser, high-pressure scrubber and high-pressure ejector, and decomposition tower. High-pressure liquid ammonia, pressurized by a plunger pump, carries the methylamine solution from the high-pressure scrubber into the reactor via the ejector. Carbon dioxide, compressed by a compressor, removes unreacted ammonia and undecomposed methylamine from the solution in the stripping tower before entering the reactor. The reactor is a tubular reactor; the reaction of carbon dioxide and ammonia to produce methylamine occurs inside the tubes, releasing heat, while byproduct steam is removed from the tubes. The methylamine solution and unreacted gas phase enter the synthesis tower from bottom to top. After a certain reaction time, the methylamine is gradually converted into urea. The unreacted gas phase further reacts to produce methylamine and provides heat for its decomposition. The unreacted gas phase in the synthesis tower is drawn off from the top and enters a high-pressure scrubber, where it is washed with methylamine solution from subsequent processes to absorb CO2 and NH3 from the tail gas of the synthesis tower. The scrubbing liquid is carried into the reactor by high-pressure liquid ammonia through an ejector. The heat released during the process is removed using high-pressure temperature-controlled water. The tail gas after scrubbing still contains a certain amount of CO2, NH3, and non-condensable gases, which are sent to a low-pressure absorption tower for further recovery before being vented. Since not all methylamine is converted into urea in the synthesis tower, a stripping tower is installed. The liquid phase after the reaction in the synthesis tower is drawn off from the upper outlet pipe and sent to the upper part of the stripping tower. It is then evenly distributed to each stripping pipe by a distributor at the top of the stripping tower. The flow rate is controlled by the liquid level of the distributor, causing the liquid to form a liquid film and descend along the pipe wall. Compressed CO2 is introduced into the lower part of the stripping tower, where it comes into countercurrent contact with the liquid phase inside the stripping pipe. Steam heating is used to provide heat outside the stripping pipe. Excess ammonia and unconverted methylamine in the liquid phase of the synthesis tower are stripped and enter the reactor from the top of the tower as a gas. The stripped liquid phase at the bottom of the tower is sent to the decomposition process. A certain liquid level is maintained at the bottom of the stripping tower to form a liquid seal, preventing high-pressure gas from entering subsequent low-pressure equipment. The liquid phase (methylamine-urea solution) at the outlet of the stripping tower is sent to the decomposition system after depressurization. The stripped gas at the outlet of the stripping tower, together with the ammonium carbamate liquid from the ammonium carbamate injector, enters the ammonium carbamate condenser. The ammonium carbamate condenser transports the gas and liquid to the urea synthesis tower through gas and liquid pipelines, respectively. The urea in the synthesis tower flows by gravity to the stripping tower, and the gas phase outlet is sent to the high-pressure scrubber. The gas at the outlet of the high-pressure scrubber contains small amounts of ammonia and carbon dioxide. These gases are sent to the low-pressure absorption tower and absorbed by the process condensate and steam condensate. The absorbed tail gas is discharged into the atmosphere. The post-processing system only includes a decomposition and absorption system; the vacuum evaporation system includes two stages: vacuum evaporation and condensation, and a process condensation treatment process has been established. The evaporated urine is sent to the final granulation process.

[0004] The stripping tower, also known as a high-pressure heat exchanger, receives the reaction mixture from the bottom of the synthesis tower. The mixture enters from the top and flows downwards into the tube bundle, forming a liquid film that flows down the tube wall before exiting from the bottom. Carbon dioxide gas from the carbon dioxide compressor enters from the bottom, and the jacket is heated with steam to strip and decompose unreacted ammonia and ammonium carbamate in the solution. Some water also evaporates. The gas exiting from the top of the stripping tower is sent to the top of the high-pressure condenser. The methylamine-urea solution exiting the bottom of the stripping tower is then sent to the decomposition tower after pressure reduction. The pressure inside the stripping tower is relatively high, approximately 13-15 MPa, while the pressure inside the decomposition tower is relatively low, approximately 0.25-2.5 MPa. A pressure-reducing valve is often installed before the methylamine-urea solution exiting the bottom of the stripping tower enters the decomposition tower to reduce its pressure. Therefore, there is a significant loss of static pressure energy at the pressure-reducing valve, which needs to be recovered and utilized. Utility Model Content

[0005] The purpose of this invention is to provide a static pressure energy recovery and utilization device for urea synthesis, which solves the problem of significant static pressure energy waste in existing static pressure energy recovery and utilization devices for urea synthesis.

[0006] The technical solution adopted in this utility model is a static pressure energy recovery and utilization device for urea synthesis, including a stripping tower, a liquid inlet pipe connected to the top of the stripping tower, a decomposition tower connected to the bottom of the stripping tower through a liquid inlet pipe, a pressure reducing valve and a flow meter installed on the liquid inlet pipe, bypass pipes connected to the liquid inlet pipes on both sides of the pressure reducing valve, and a power generation device installed on the bypass pipes.

[0007] The features of this utility model also include: The bottom of the stripping tower is connected to an air inlet pipe.

[0008] An exhaust pipe is connected to the top of the stripping tower.

[0009] The power generation unit includes a water turbine, which is installed on a bypass pipeline and connected to a generator.

[0010] An electric valve is installed on the bypass pipeline of the power generation unit near the stripping tower.

[0011] A manual valve is connected to the bypass pipe of the power generation unit near the decomposition tower.

[0012] The water turbine is connected to the generator via a coupling. An air inlet pipe is connected to the top of the stripping tower.

[0013] The bottom of the stripping tower is connected to a liquid outlet pipe.

[0014] The generator, pressure reducing valve, and flow meter are all electrically connected to a control cabinet.

[0015] The beneficial effects of this utility model are: This invention, by setting a bypass pipe at the pressure reducing valve and installing a water turbine and generator on the bypass pipe, can maximize the recovery and utilization of the static pressure energy of the methylamine solution between the stripping tower and the decomposition tower. The water turbine drives the generator to generate electricity for other electrical equipment, thereby reducing the power consumption of the static pressure energy recovery and utilization device used for urea synthesis. Attached Figure Description

[0016] Figure 1 This is a structural diagram of the present invention.

[0017] In the diagram, 1. Stripping tower, 2. Liquid inlet pipe, 3. Gas inlet pipe, 4. Gas inlet pipe, 5. Liquid outlet pipe, 6. Exhaust pipe, 7. Flow meter, 8. Pressure reducing valve, 9. Liquid inlet pipe, 10. Decomposition tower, 11. Bypass pipe, 12. Electric valve, 13. Power generation unit, 131. Water turbine, 132. Generator, 14. Manual valve, 15. Control cabinet. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0019] A static pressure energy recovery and utilization device for urea synthesis, see [link / reference]. Figure 1 It includes a stripping tower 1, with an inlet pipe 2 connected to the top of the stripping tower 1, and a decomposition tower 10 connected to the bottom of the stripping tower 1 via an inlet pipe 9. A pressure reducing valve 8 and a flow meter 7 are installed on the inlet pipe 9, and bypass pipes 11 are connected to the inlet pipes 9 on both sides of the pressure reducing valve 8. A power generation device 13 is installed on the bypass pipe 11.

[0020] The bottom of the stripping tower 1 is connected to the gas inlet pipe 3, and the top of the stripping tower 1 is connected to the exhaust pipe 6. The generated gas is discharged from the exhaust pipe 6.

[0021] The power generation unit 13 includes a water turbine 131, which is installed on the bypass pipe 11 and is connected to the generator 132 via a coupling.

[0022] An electric valve 12 is installed on the bypass pipe 11 of the power generation unit 13 near the stripping tower 1, and a manual valve 14 is connected to the bypass pipe 11 of the power generation unit 13 near the decomposition tower 10.

[0023] The top of the stripping tower 1 is connected to an air inlet pipe 4, and the bottom of the stripping tower 1 is connected to an outlet pipe 5.

[0024] The generator 132, pressure reducing valve 8, and flow meter 7 are electrically connected to the control cabinet 15, and the generator 132 is connected to the power grid through the control cabinet 15.

[0025] The working process of this utility model: The methylamine-urea solution enters the stripping tower 1 through the inlet pipe 2. Carbon dioxide, pressurized by the carbon dioxide compressor, enters the stripping tower 1 through the gas inlet pipe 3. Steam from the outside enters the stripping tower through the gas inlet pipe 4 and indirectly contacts the methylamine-urea solution through the heat exchange coil. The steam is condensed and discharged from the outlet pipe 5 in the form of condensate. The methylamine-urea solution and carbon dioxide are in direct countercurrent contact. Under the heating of steam, the unreacted ammonia and ammonium carbamate in the solution are stripped and decomposed. Ammonia and carbon dioxide are continuously overflowed, and some water is also evaporated. The water is discharged from the exhaust pipe 6 and sent to the total condensation reactor through the ammonium carbamate injector. The liquid phase methylamine-urea solution enters the decomposition tower 10 through the inlet pipe 9 and after being depressurized by the pressure reducing valve 8.

[0026] The working principle of this utility model: The methylamine solution discharged from the stripping tower 1 enters the turbine 131 through the bypass pipe 11 at the pressure reducing valve 8. The turbine 131 converts the static pressure energy of the methylamine solution before and after the pressure reducing valve 8 into kinetic energy. The turbine 131 outputs the kinetic energy to the generator 132, which in turn converts the kinetic energy into electrical energy to power other electrical equipment, thereby reducing the energy consumption of the static pressure energy recovery and utilization device used for urea synthesis.

[0027] During normal operation, the electric valve 12 is slowly opened, and the pressure reducing valve 8 is slowly closed in conjunction with it, causing the turbine 131 to increase in speed. When the turbine 131 speed equals the synchronous speed of the generator 132, the control switch for connecting the generator 132 to the power grid is activated. The electric valve 12 continues to be slowly opened, and the pressure reducing valve 8 is slowly closed in conjunction with it, causing the turbine 131 speed to continue to increase. When the turbine 131 speed is higher than the synchronous speed of the generator 132, the generator 132 begins to generate electricity until the electric valve 12 is fully open and the pressure reducing valve 8 is fully closed. At this point, the generator enters normal operation, and the output of the generator 132 reaches its maximum value.

[0028] When the generator 13 fails, the control switch connecting the generator 132 to the power grid is tripped by the control cabinet 15, causing the generator 132 to stop generating electricity. At the same time, the electric valve 12 is closed and the pressure reducing valve 8 is opened to the set value, reducing the speed of the turbine 131 until it stops rotating, restoring the original operating state.

[0029] Example 1: A static pressure energy recovery and utilization device for urea synthesis includes a stripping tower 1, with an inlet pipe 2 connected to the top of the stripping tower 1 and a decomposition tower 10 connected to the bottom of the stripping tower 1 via an inlet pipe 9. A pressure reducing valve 8 and a flow meter 7 are installed on the inlet pipe 9. Bypass pipes 11 are connected to the inlet pipes 9 on both sides of the pressure reducing valve 8, and a power generation device 13 is installed on the bypass pipes 11.

[0030] The bottom of the stripping tower 1 is connected to an air inlet pipe 3.

[0031] The top of the stripping tower 1 is connected to an exhaust pipe 6.

[0032] The power generation unit 13 includes a water turbine 131, which is installed on the bypass pipe 11 and connected to a generator 132.

[0033] An electric valve 12 is installed on the bypass pipe 11 near the stripping tower 1 of the power generation unit 13.

[0034] A manual valve 14 is connected to the bypass pipe 11 of the power generation unit 13 near the decomposition tower 10.

[0035] The generator 132, pressure reducing valve 8, and flow meter 7 are electrically connected to the control cabinet 15.

[0036] Example 2: A static pressure energy recovery and utilization device for urea synthesis includes a stripping tower 1, with an inlet pipe 2 connected to the top of the stripping tower 1 and a decomposition tower 10 connected to the bottom of the stripping tower 1 via an inlet pipe 9. A pressure reducing valve 8 and a flow meter 7 are installed on the inlet pipe 9. Bypass pipes 11 are connected to the inlet pipes 9 on both sides of the pressure reducing valve 8, and a power generation device 13 is installed on the bypass pipes 11.

[0037] The bottom of the stripping tower 1 is connected to an air inlet pipe 3.

[0038] The top of the stripping tower 1 is connected to an exhaust pipe 6.

[0039] The power generation unit 13 includes a water turbine 131, which is installed on the bypass pipe 11 and connected to a generator 132.

[0040] The water turbine 131 is connected to the generator 132 via a coupling. The top of the stripping tower 1 is connected to an air inlet pipe 4.

[0041] The bottom of the stripping tower 1 is connected to the liquid outlet pipe 5.

[0042] The generator 132, pressure reducing valve 8, and flow meter 7 are electrically connected to the control cabinet 15.

[0043] Example 3: A static pressure energy recovery and utilization device for urea synthesis includes a stripping tower 1, with an inlet pipe 2 connected to the top of the stripping tower 1 and a decomposition tower 10 connected to the bottom of the stripping tower 1 via an inlet pipe 9. A pressure reducing valve 8 and a flow meter 7 are installed on the inlet pipe 9. Bypass pipes 11 are connected to the inlet pipes 9 on both sides of the pressure reducing valve 8, and a power generation device 13 is installed on the bypass pipes 11.

[0044] The bottom of the stripping tower 1 is connected to an air inlet pipe 3.

[0045] The top of the stripping tower 1 is connected to an exhaust pipe 6.

[0046] The power generation unit 13 includes a water turbine 131, which is installed on the bypass pipe 11 and connected to a generator 132.

[0047] An electric valve 12 is installed on the bypass pipe 11 near the stripping tower 1 of the power generation unit 13.

[0048] The water turbine 131 is connected to the generator 132 via a coupling.

[0049] The generator 132, pressure reducing valve 8, and flow meter 7 are electrically connected to the control cabinet 15.

[0050] Example 4: A static pressure energy recovery and utilization device for urea synthesis includes a stripping tower 1, with an inlet pipe 2 connected to the top of the stripping tower 1 and a decomposition tower 10 connected to the bottom of the stripping tower 1 via an inlet pipe 9. A pressure reducing valve 8 and a flow meter 7 are installed on the inlet pipe 9. Bypass pipes 11 are connected to the inlet pipes 9 on both sides of the pressure reducing valve 8, and a power generation device 13 is installed on the bypass pipes 11.

[0051] The bottom of the stripping tower 1 is connected to an air inlet pipe 3.

[0052] The top of the stripping tower 1 is connected to an exhaust pipe 6.

[0053] The power generation unit 13 includes a water turbine 131, which is installed on the bypass pipe 11 and connected to a generator 132.

[0054] An electric valve 12 is installed on the bypass pipe 11 near the stripping tower 1 of the power generation unit 13.

[0055] A manual valve 14 is connected to the bypass pipe 11 of the power generation unit 13 near the decomposition tower 10.

[0056] The water turbine 131 is connected to the generator 132 via a coupling.

[0057] The generator 132, pressure reducing valve 8, and flow meter 7 are electrically connected to the control cabinet 15.

[0058] Example 5: A static pressure energy recovery and utilization device for urea synthesis includes a stripping tower 1, with an inlet pipe 2 connected to the top of the stripping tower 1 and a decomposition tower 10 connected to the bottom of the stripping tower 1 via an inlet pipe 9. A pressure reducing valve 8 and a flow meter 7 are installed on the inlet pipe 9. Bypass pipes 11 are connected to the inlet pipes 9 on both sides of the pressure reducing valve 8, and a power generation device 13 is installed on the bypass pipes 11.

[0059] The bottom of the stripping tower 1 is connected to an air inlet pipe 3.

[0060] The top of the stripping tower 1 is connected to an exhaust pipe 6.

[0061] The power generation unit 13 includes a water turbine 131, which is installed on the bypass pipe 11 and connected to a generator 132.

[0062] A manual valve 14 is connected to the bypass pipe 11 of the power generation unit 13 near the decomposition tower 10.

[0063] The top of the stripping tower 1 is connected to an air inlet pipe 4.

[0064] Example 6: A static pressure energy recovery and utilization device for urea synthesis includes a stripping tower 1, with an inlet pipe 2 connected to the top of the stripping tower 1 and a decomposition tower 10 connected to the bottom of the stripping tower 1 via an inlet pipe 9. A pressure reducing valve 8 and a flow meter 7 are installed on the inlet pipe 9. Bypass pipes 11 are connected to the inlet pipes 9 on both sides of the pressure reducing valve 8, and a power generation device 13 is installed on the bypass pipes 11.

[0065] The bottom of the stripping tower 1 is connected to an air inlet pipe 3.

[0066] An electric valve 12 is installed on the bypass pipe 11 near the stripping tower 1 of the power generation unit 13.

[0067] A manual valve 14 is connected to the bypass pipe 11 of the power generation unit 13 near the decomposition tower 10.

[0068] The bottom of the stripping tower 1 is connected to the liquid outlet pipe 5.

[0069] Example 7: A static pressure energy recovery and utilization device for urea synthesis includes a stripping tower 1, with an inlet pipe 2 connected to the top of the stripping tower 1 and a decomposition tower 10 connected to the bottom of the stripping tower 1 via an inlet pipe 9. A pressure reducing valve 8 and a flow meter 7 are installed on the inlet pipe 9. Bypass pipes 11 are connected to the inlet pipes 9 on both sides of the pressure reducing valve 8, and a power generation device 13 is installed on the bypass pipes 11.

[0070] The bottom of the stripping tower 1 is connected to an air inlet pipe 3.

[0071] The power generation unit 13 includes a water turbine 131, which is installed on the bypass pipe 11 and connected to a generator 132.

[0072] A manual valve 14 is connected to the bypass pipe 11 of the power generation unit 13 near the decomposition tower 10.

[0073] The water turbine 131 is connected to the generator 132 via a coupling. Example 8: A static pressure energy recovery and utilization device for urea synthesis includes a stripping tower 1, with an inlet pipe 2 connected to the top of the stripping tower 1 and a decomposition tower 10 connected to the bottom of the stripping tower 1 via an inlet pipe 9. A pressure reducing valve 8 and a flow meter 7 are installed on the inlet pipe 9. Bypass pipes 11 are connected to the inlet pipes 9 on both sides of the pressure reducing valve 8, and a power generation device 13 is installed on the bypass pipes 11.

[0074] The top of the stripping tower 1 is connected to an exhaust pipe 6.

[0075] The power generation unit 13 includes a water turbine 131, which is installed on the bypass pipe 11 and connected to a generator 132.

[0076] An electric valve 12 is installed on the bypass pipe 11 near the stripping tower 1 of the power generation unit 13.

[0077] The water turbine 131 is connected to the generator 132 via a coupling. The bottom of the stripping tower 1 is connected to the liquid outlet pipe 5.

Claims

1. A static pressure energy recovery and utilization device for urea synthesis, characterized in that, The equipment includes a stripping tower (1), with an inlet pipe (2) connected to the top of the stripping tower (1) and a decomposition tower (10) connected to the bottom of the stripping tower (1) via an inlet pipe (9). A pressure reducing valve (8) and a flow meter (7) are installed on the inlet pipe (9). Bypass pipes (11) are connected to the inlet pipes (9) on both sides of the pressure reducing valve (8). A power generation device (13) is installed on the bypass pipes (11).

2. The static pressure energy recovery and utilization device for urea synthesis according to claim 1, characterized in that, The bottom of the stripping tower (1) is connected to an air inlet pipe (3).

3. The static pressure energy recovery and utilization device for urea synthesis according to claim 1, characterized in that, The top of the stripping tower (1) is connected to an exhaust pipe (6).

4. The static pressure energy recovery and utilization device for urea synthesis according to any one of claims 1-3, characterized in that, The power generation device (13) includes a water turbine (131) which is installed on a bypass pipe (11) and is connected to a generator (132).

5. The static pressure energy recovery and utilization device for urea synthesis according to any one of claims 1-3, characterized in that, An electric valve (12) is installed on the bypass pipe (11) of the power generation unit (13) near the stripping tower (1).

6. The static pressure energy recovery and utilization device for urea synthesis according to any one of claims 1-3, characterized in that, The power generation device (13) is connected to a manual valve (14) on the bypass pipe (11) near the decomposition tower (10).

7. The static pressure energy recovery and utilization device for urea synthesis according to claim 4, characterized in that, The water turbine (131) is connected to the generator (132) via a coupling.

8. The static pressure energy recovery and utilization device for urea synthesis according to any one of claims 1-3, characterized in that, The top of the stripping tower (1) is connected to an air inlet pipe (4).

9. The static pressure energy recovery and utilization device for urea synthesis according to any one of claims 1-3, characterized in that, The bottom of the stripping tower (1) is connected to a liquid outlet pipe (5).

10. The static pressure energy recovery and utilization device for urea synthesis according to claim 4, characterized in that, The generator (132), pressure reducing valve (8), and flow meter (7) are electrically connected to the control cabinet (15).

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