Steady-state operation control system for steam pipe network

Abstract

The utility model discloses a steady-state operation control system for a steam pipe network, which comprises a buffer decompression system, the buffer decompression system is connected with a heat exchanger, the heat exchanger is connected with a heat recovery device, and a back pressure type power generation device is arranged in the buffer decompression system. According to the operation characteristics of the ammonia synthesis device, a steam official website system meeting the production requirement is constructed, and meanwhile, an active temperature and pressure reduction system is arranged between pipe-level official websites; according to the operation characteristics of the ammonia synthesis device, a steam official website system meeting the production requirement is constructed, and meanwhile, an active temperature and pressure reduction system is arranged between pipe-level official websites.

Description

TECHNICAL FIELD

[0001] The utility model relates to chemical energy utilization technical field, especially a steam pipe network steady state operation control system. BACKGROUND

[0002] In order to make full use of waste heat generated in the gas purification and synthesis reaction process, the coal-to-ammonia plant generally sets up a waste heat boiler to convert the waste heat generated in the reaction into low-pressure steam for use in other rectification devices, different steam pipe networks are connected through temperature-reducing and pressure-reducing systems to form a complete steam system network, when the system steam is in surplus, it can be adjusted through the set vent valve, and steam waste will be caused by venting.

[0003] The coal-to-ammonia plant is closely related to the production of ethylene glycol. A large amount of waste heat is generated in the production process of the coal-to-ammonia plant, and these waste heat can be recycled and utilized through a circulating water system, thereby improving energy utilization efficiency. In the low-pressure steam recovered by the circulating water system, the surplus steam is mainly sent to the park and other chemical plants.

[0004] When the ethylene glycol device is shut down, the rectification steam is greatly reduced, or after the production capacity of synthetic ammonia is improved, a large amount of surplus low-pressure steam in the production of synthetic ammonia will continue to accumulate, at which time the internal low-pressure steam will not be able to be consumed, in order to balance the pipe network pressure, part of the steam will be vented, the pipe network pressure will be adjusted frequently, and the system pipe network pressure will be frequently fluctuated.

[0005] The long-time venting of low-pressure steam not only wastes energy, but also causes visual pollution and noise pollution, which is not conducive to the economic operation of the plant and the improvement of the environment. SUMMARY

[0006] The technical problem to be solved by the utility model is to provide a steam pipe network steady state operation control system, which is transformed from the existing steam pipe network, a pressure-reducing system is constructed, and the stable operation of the correct steam system and energy recovery system and the economy of the project are ensured.

[0007] To solve the above technical problems, the utility model adopts the technical scheme that

[0008] A steam pipe network steady state operation control system, comprising a buffer pressure-reducing system, the buffer pressure-reducing system is connected with a heat exchanger, the heat exchanger is connected with a heat recovery device, and a back pressure power generation device is arranged in the buffer pressure-reducing system.

[0009] The heat exchanger comprises a first heat exchanger and a second heat exchanger, the first heat exchanger and the second heat exchanger are connected with a first heat recovery machine and a second heat recovery machine respectively, and the two groups of heat exchangers are in standby for each other in combination with the heat recovery device.

[0010] The back pressure type power generation device of the buffer pressure reducing system has a bypass pressure reducing device.

[0011] The bypass pressure reducing device comprises a first valve, a pressure reducing valve and a second valve connected in sequence, and pipelines at both ends of the back pressure type power generation device are connected to the first valve and the second valve respectively.

[0012] The input end and the output end of the buffer pressure reducing system are respectively provided with an input pressure gauge and an output pressure gauge, an input flow gauge and an output flow gauge, the input pressure gauge, the output pressure gauge, the input flow gauge and the output flow gauge are connected to an input end of a DCS control system, and the back pressure type power generation device is controlled by the DCS control system.

[0013] The back pressure type power generation device comprises a steam turbine, a generator and a steam turbine control device, and the steam turbine control device is controlled by a DCS sending control signal.

[0014] The first heat exchanger and the second heat exchanger are circulating water type heat exchange devices, which are used for condensing steam and supplying heat absorbed by the steam to the first heat recovery machine and the second heat recovery machine.

[0015] The utility model provides a kind of steam pipe network steady operation control system, according to the operating characteristics of synthetic ammonia plant, construct the steam official website system satisfying production, simultaneously, set up initiative temperature-reducing pressure-reducing system between pipe level official website;According to the operating characteristics of synthetic ammonia plant, construct the steam official website system satisfying production, simultaneously, set up initiative temperature-reducing pressure-reducing system between pipe level official website BRIEF DESCRIPTION OF DRAWINGS

[0016] The utility model will be further described below in connection with drawings and examples:

[0017] Figure 1 It is the structure schematic diagram of the steam pipe network steady operation control system of the utility model;

[0018] Figure 2 It is the structure schematic diagram of buffer pressure reducing system;

[0019] Figure 3 It is the structure schematic diagram of preferred buffer pressure reducing system;

[0020] Figure 4 It is the structure schematic diagram of back pressure type power generation device.

[0021] In the drawing: buffer pressure reducing system 1, filter 101, first valve 102, pressure reducing valve 103, second valve 104, input pressure gauge 105, output pressure gauge 106, input flow gauge 107, output flow gauge 108, first heat exchanger 2, first heat recovery machine 3, second heat exchanger 4, second heat recovery machine 5, condensate buffer tank 6, back pressure type power generation device 7, steam turbine 71, generator 72. DETAILED DESCRIPTION

[0022] As Figures 1-4 shown, a steam pipe network steady operation control system, comprising a buffer pressure reducing system 1, the buffer pressure reducing system 1 is connected with a heat exchanger, the heat exchanger is connected with a heat recovery device, a back pressure power generation device 7 is arranged in the buffer pressure reducing system 1.

[0023] The back pressure power generation device 7 can reduce the accumulated low pressure steam pressure in the steam pipe network caused by the shutdown of the ethylene glycol device to a pressure value range that can be utilized by the heat recovery system, and the generator generates power, and the power generation of the heat recovery system, while stabilizing the pressure of the accumulated steam, also greatly improves the energy recovery rate.

[0024] The heat exchanger comprises a first heat exchanger 2 and a second heat exchanger 4, the first heat exchanger 2 and the second heat exchanger 4 are connected with a first heat recovery machine 3 and a second heat recovery machine 5 respectively, and the two groups of heat exchangers are standby for each other in combination with the heat recovery device.

[0025] The back pressure power generation device 7 in the buffer pressure reducing system 1 is provided with a bypass pressure reducing device.

[0026] The bypass pressure reducing device comprises a first valve 102, a pressure reducing valve 103 and a second valve 104 connected in sequence, and the pipelines at both ends of the back pressure power generation device 7 are connected at both ends of the first valve 102 and the second valve 104 respectively.

[0027] The input end and the output end of the buffer pressure reducing system 1 are respectively provided with an input pressure gauge 105 and an output pressure gauge 106, an input flow gauge 107 and an output flow gauge 108, the input pressure gauge 105, the output pressure gauge 106, the input flow gauge 107 and the output flow gauge 108 are connected with the input end of a DCS control system, and the back pressure power generation device 7 is controlled by the DCS control system.

[0028] By detecting the input pressure and the output pressure of the buffer pressure reducing system 1, it is judged whether the pressure input to the heat recovery end exceeds the set value, if it exceeds, the DCS system controls and regulates the operation state of the back pressure power generation device 7 through the calculation of the input pressure value and the output pressure difference value, and the input flow and the output flow.

[0029] The back pressure power generation device 7 comprises a steam turbine 71, a generator 72 and a steam turbine control device, and the steam turbine control device is controlled by a control signal sent by the DCS.

[0030] The first heat exchanger 2 and the second heat exchanger 4 are circulating water type heat exchange devices, which are used for condensing steam and supplying the heat absorbed thereby to the first heat recovery machine 3 and the second heat recovery machine 5.

[0031] Example 1:

[0032] A synthetic ammonia plant has three circulating fluidized bed boilers, two operating and one standby, with a single boiler steam production of about 650 t / h, and nine waste heat boilers for purification of synthesis, with about 400 t of low-pressure steam sent out per hour, with the surplus steam mainly sent to the park, nylon plant and phosphate fertilizer plant.

[0033] Currently, after the glycol unit is shut down, the steam for rectification is greatly reduced, and after the new project is completed, the low-pressure steam production will continue to increase. At that time, the internal low-pressure steam of the sub-factory will not be able to be consumed, and in order to balance the pipe network pressure, part of the steam will be vented, the pipe network pressure will be adjusted frequently, and the system pipe network pressure will fluctuate frequently.

[0034] Based on the above problems, the existing steam pipe network is modified, a cascade pressure reduction system is built, a steam energy recovery system is added to the lowest steam pressure pipe network, and after the addition of the back pressure power generation device 7, the 0.6 Mpa pressure of the pipe network is converted to 0.08 Mpa for energy recovery, and the bypass pressure reducing valve can also convert the 0.6 Mpa pressure to 0.08 Mpa, specifically:

[0035] The 0.6 MPa steam main pipe (DN400) of the glycol plant is connected to the electric valve after the 53 rectification boundary, and the new generator is designed to bypass the pressure reducer to reduce the pressure to 0.08 MPa steam and then directly enter the original 53 waste heat recovery turbine unit to generate electricity.

Claims

1. A steam network steady state operation control system, characterized by: Including buffer The pressure reducing system (1) is connected with a heat exchanger, the heat exchanger is connected with a heat recovery device, and the back pressure power generation device (7) is arranged in the buffer pressure reducing system (1).

2. A steady state operation control system for a steam pipe network according to claim 1, characterized in that, The heat exchanger comprises a first heat exchanger (2) and a second heat exchanger (4), the first heat exchanger (2) and the second heat exchanger (4) are connected with a first heat recovery machine (3) and a second heat recovery machine (5) respectively, and the two groups of heat exchangers are used as backup for each other in combination with the heat recovery device.

3. A steady state operation control system for a steam pipe network according to claim 2, characterized in that, The back pressure power generation device (7) in the buffer pressure reducing system (1) is provided with a bypass pressure reducing device.

4. A steady state operation control system for a steam pipe network according to claim 3, characterized in that, The bypass pressure reducing device comprises a first valve (102), a pressure reducing valve (103) and a second valve (104) connected in sequence, and pipelines at two ends of the back pressure power generation device (7) are connected to the two ends of the first valve (102) and the second valve (104) respectively.

5. A steady state operation control system for a steam pipe network according to claim 4, characterized in that, The input end and the output end of the buffer pressure reducing system (1) are respectively provided with an input pressure gauge (105) and an output pressure gauge (106), an input flow gauge (107) and an output flow gauge (108), the input pressure gauge (105), the output pressure gauge (106), the input flow gauge (107) and the output flow gauge (108) are connected with an input end of a DCS control system, and the back pressure power generation device (7) is controlled by the DCS control system.

6. A steady state operation control system of a steam pipe network according to claim 5, characterized in that, The back pressure power generation device (7) comprises a steam turbine (71), a generator (72) and a steam turbine control device, and the steam turbine control device is controlled by a DCS sending control signal.

7. A steady state operation control system of a steam pipe network according to claim 6, characterized in that, The first heat exchanger (2) and the second heat exchanger (4) are circulating water type heat exchange devices, which are used for condensing steam and supplying heat absorbed by the steam to the first heat recovery machine (3) and the second heat recovery machine (5).

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