Device for increasing content of methane in liquid nitrogen wash inlet gas

Abstract

The utility model discloses a device for increasing methane content in liquid nitrogen wash inlet gas, which comprises a liquid nitrogen wash fuel gas pipe network, an oil-free lubrication gas circulating compressor and a gas cooler, and the output end of the liquid nitrogen wash fuel gas pipe network is connected to the input end of the oil-free lubrication gas circulating compressor; compared with the prior art, the oil-free lubricating gas circulating compressor, the gas cooler, the circulating water pipe network water pipe network and the circulating water pipe network water return pipe network are arranged on the liquid nitrogen washing fuel gas pipe network, so that the structure is simple, the installation and the use are convenient, and the process principles of pressurization, cooling and recovery are fully utilized; therefore, the purpose of intermittently increasing the content of methane in the liquid nitrogen wash inlet gas to 1500ppm is achieved, the stable operation of the liquid nitrogen wash device is ensured, the problem that the resistance of a raw material gas channel from the liquid nitrogen wash inlet to the nitrogen wash tower inlet is intermittently increased to influence the production can be solved, and the stable operation of the liquid nitrogen wash device is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid nitrogen washing systems, in particular to a device for increasing the methane content in liquid nitrogen washing inlet gas. Background Art

[0002] According to the requirements of coal chemical industry and power generation process, the resistance of raw gas pipeline has increased since the liquid nitrogen washing device was put into operation. The main phenomena are as follows: ① The pressure difference between the raw gas entering the 1# raw gas cooler (E-2602) and the nitrogen washing tower (C-2601) gradually increases from the normal value of about 25kPa to 60kPa, or even higher; ② The temperature of the reflux gas such as purified gas, fuel gas, and circulating hydrogen out of the 2# raw gas cooler (E-2603) drops sharply, and the cooling capacity is obviously "not able to be carried down"; ③ The temperature of the raw gas entering the nitrogen washing tower rises, and the pressure difference of the nitrogen washing tower rises accordingly, and the washing condition of the liquid nitrogen washing system deteriorates, and even the tower plate of the nitrogen washing tower accumulates liquid and the liquid level of the tower kettle drops rapidly; ④ When the liquid level of the nitrogen washing tower is uncontrollable, there will often be a trace amount (CO content) in the purified gas running high, affecting the long-term stable operation of the aerospace furnace device. For this reason, the utility model proposes a device for increasing the methane content in the liquid nitrogen washing inlet gas. Utility Model Content

[0003] The utility model aims to provide a device for increasing the methane content in the liquid nitrogen washing inlet gas, so as to solve the problem that the resistance of the raw gas pipeline increases due to the slow crystallization of CH4 in the raw gas on the inner wall of the pipeline, which affects the safety and stability of the liquid nitrogen washing device and the long-term stable operation of the gasification device.

[0004] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a device for increasing the methane content in the liquid nitrogen washing inlet gas, comprising a liquid nitrogen washing fuel gas pipeline network, an oil-free lubricating gas circulating compressor and a gas cooler, wherein the output end of the liquid nitrogen washing fuel gas pipeline network is connected to the input end of the oil-free lubricating gas circulating compressor, the output end of the oil-free lubricating gas circulating compressor is connected to the input end of the gas cooler, the output end of the gas cooler is connected to a low-temperature methanol washing station flash steam compressor, and the gas cooler is also equipped with a circulating water network upper water network and a circulating water network return water network.

[0005] As a preferred technical solution of the utility model, a loop pipe is provided on one side of the oil-free lubrication gas circulation compressor, and a regulating valve is provided on the loop pipe.

[0006] As a preferred technical solution of the utility model, the input end of the loop pipe is connected to the connection between the oil-free lubricated gas circulation compressor and the gas cooler, and the output end of the loop pipe is connected to the connection between the liquid nitrogen washed fuel gas pipeline network and the oil-free lubricated gas circulation compressor.

[0007] As a preferred technical solution of the utility model, a branch pipeline is provided on one side of the loop pipeline, and a remote automatic regulating valve group is provided on the branch pipeline.

[0008] As a preferred technical solution of the utility model, the remote automatic regulating valve group includes a plurality of automatic regulating valves, and each automatic regulating valve is electrically connected to the DCS remote control system.

[0009] As a preferred technical solution of the utility model, the input end of the branch pipeline is connected to the connection between the gas cooler and the flash steam compressor of the low-temperature methanol washing station, the output end of the branch pipeline is connected to the liquid nitrogen washing fuel gas pipeline network, and the output end of the branch pipeline is located on the side of the loop pipeline output end away from the oil-free lubricated gas circulation compressor.

[0010] As a preferred technical solution of the utility model, the output end of the flash steam compressor of the low-temperature methanol washing station is connected to a low-temperature methanol washing system.

[0011] Compared with the prior art, the beneficial effects of the utility model are:

[0012] The utility model discloses a device for increasing the methane content in the inlet gas of liquid nitrogen washing. By arranging an oil-free lubricating gas circulation compressor, a gas cooler, a water pipe network of a circulating water pipe network, and a water return pipe network of a circulating water pipe network on a liquid nitrogen washing fuel gas pipe network, the device has a simple structure, is easy to install and use, and makes full use of the process principles of pressurization, cooling and temperature reduction, and recycling, thereby achieving the purpose of intermittently increasing the methane content in the inlet gas of the liquid nitrogen washing to 1500ppm, ensuring the stable operation of the liquid nitrogen washing device, and solving the problem that the resistance of the raw gas channel from the liquid nitrogen washing inlet to the nitrogen washing tower inlet is intermittently increased and affects the production, thereby ensuring the stable operation of the liquid nitrogen washing device.

[0013] Other features and advantages of the present invention will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0015] In the figure: 1. Liquid nitrogen washing fuel gas pipeline network; 2. Oil-free lubricated gas circulation compressor; 3. Gas cooler; 4. Circulating water pipeline network; 5. Circulating water pipeline network return pipeline network; 6. Low-temperature methanol washing station flash steam compressor; 7. Loop pipe line; 8. Remote automatic regulating valve group; 9. Branch pipe line. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0018] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] See also Figure 1 In this embodiment, a device for increasing the methane content in the liquid nitrogen washing inlet gas is provided, comprising a liquid nitrogen washing fuel gas pipeline network 1, an oil-free lubricated gas circulation compressor 2 and a gas cooler 3, wherein the output end of the liquid nitrogen washing fuel gas pipeline network 1 is connected to the input end of the oil-free lubricated gas circulation compressor 2, wherein the oil-free lubricated gas circulation compressor 2 is used to pressurize the 0.3-0.4Mpa gas entering from the liquid nitrogen washing fuel gas outlet to 1.3-1.5Mpa, and transport it to the gas cooler 3, the output end of the oil-free lubricated gas circulation compressor 2 is connected to the input end of the gas cooler 3, wherein the gas cooler 3 ... The gas pressurized by the oil-free lubrication gas circulation compressor 2 is cooled to 25-35°C with circulating water, and then transported to the low-temperature methanol washing station flash steam compressor 6. The output end of the gas cooler 3 is connected to the low-temperature methanol washing station flash steam compressor 6. The gas cooler 3 is also equipped with a circulating water network water network 4 and a circulating water network return water network 5. Because the CH4 content in the liquid nitrogen washing fuel gas is relatively high, the CH4 content is about 3.0%, which is three orders of magnitude higher than the CH4 content of the raw gas, so part of the liquid nitrogen washing fuel gas can be recovered to the low-temperature methanol washing inlet to increase the methane content in the liquid nitrogen washing inlet raw gas.

[0020] It should be noted that this technology highlights the impact of changes in the methane content in the raw gas beforehand on the operation of the liquid nitrogen washing device, breaks through the limitations of thinking, intentionally increases the methane content in the raw gas, tries to explore a suitable methane content in the raw gas, and selects a more suitable methane content.

[0021] In this embodiment, a loop pipe 7 is provided on one side of the oil-free lubricated gas circulating compressor 2, and its function is to adjust and control the outlet pressure of the oil-free lubricated gas circulating compressor 2 within an appropriate index range to prevent overpressure and ensure the safe and stable operation of the oil-free lubricated gas circulating compressor 2; a regulating valve is provided on the loop pipe 7, and the input end of the loop pipe 7 is connected to the connection between the oil-free lubricated gas circulating compressor 2 and the gas cooler 3, and the output end of the loop pipe 7 is connected to the connection between the liquid nitrogen washed fuel gas pipeline network 1 and the oil-free lubricated gas circulating compressor 2.

[0022] In this embodiment, a stream of gas is divided from the liquid nitrogen washing fuel gas pipeline network 1 to the input port of the oil-free lubricated gas circulation compressor 2, which is pressurized to 1.6Mpa by the oil-free lubricated gas circulation compressor 2, and then cooled to 25-35°C by circulating water at 20-30°C through the outlet gas cooler 3, and then transported to the flash steam compressor 6 at the low-temperature methanol washing station, and finally further pressurized to 3.5Mpa by the flash steam compressor, entering the low-temperature methanol washing system, and then to the liquid nitrogen washing inlet, so as to intermittently increase the methane content in the liquid nitrogen washing inlet gas to 1500ppm, solve the problem of intermittent increase in the resistance of the raw gas channel from the liquid nitrogen washing inlet to the nitrogen washing tower inlet affecting production, thereby ensuring the stable operation of the liquid nitrogen washing device; at the same time, the remote DCS central control microcomputer automatic adjustment operation is realized, thereby improving the automatic operation level and production efficiency of the aerospace furnace device.

[0023] In this embodiment, a branch pipe 9 is provided on one side of the loop pipe 7, which is used to adjust and control the output gas volume of the oil-free lubrication gas circulation compressor 2, so as to control the methane content in the appropriate gas, and can also realize remote DCS control operation to improve the automatic control of the device; a remote automatic regulating valve group 8 is provided on the branch pipe 9, and the remote automatic regulating valve group 8 includes a plurality of automatic regulating valves, each of which is electrically connected to the DCS remote control system. By using the remote automatic regulating valve group 8, the DCS remote central control microcomputer can be automatically adjusted, thereby reducing the labor intensity of the operator.

[0024] In this embodiment, the input end of the branch pipeline 9 is connected to the connection between the gas cooler 3 and the low-temperature methanol washing station flash steam compressor 6, the output end of the branch pipeline 9 is connected to the liquid nitrogen washing fuel gas pipeline network 1, and the output end of the branch pipeline 9 is located on the side of the loop pipeline 7 away from the oil-free lubricated gas circulation compressor 2.

[0025] In this embodiment, the output end of the flash steam compressor 6 of the low-temperature methanol washing station is connected to a low-temperature methanol washing system.

[0026] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A device for increasing the methane content in the liquid nitrogen washing inlet gas, characterized in that: The invention comprises a liquid nitrogen fuel gas washing pipeline network (1), an oil-free lubricating gas circulation compressor (2) and a gas cooler (3), wherein the output end of the liquid nitrogen fuel gas washing pipeline network (1) is connected to the input end of the oil-free lubricating gas circulation compressor (2), the output end of the oil-free lubricating gas circulation compressor (2) is connected to the input end of the gas cooler (3), the output end of the gas cooler (3) is connected to a low-temperature methanol washing station flash steam compressor (6), and the gas cooler (3) is also equipped with a circulating water pipeline network (4) and a circulating water pipeline network return water pipeline network (5).

2. The device for increasing the methane content in the liquid nitrogen washing inlet gas according to claim 1, characterized in that: A loop pipe (7) is provided on one side of the oil-free lubrication gas circulation compressor (2), and a regulating valve is provided on the loop pipe (7).

3. The device for increasing the methane content in the liquid nitrogen washing inlet gas according to claim 2, characterized in that: The input end of the loop pipe (7) is connected to the connection between the oil-free lubricating gas circulation compressor (2) and the gas cooler (3), and the output end of the loop pipe (7) is connected to the connection between the liquid nitrogen washed fuel gas pipeline network (1) and the oil-free lubricating gas circulation compressor (2).

4. The device for increasing the methane content in the liquid nitrogen washing inlet gas according to claim 3 is characterized in that: A branch pipeline (9) is provided on one side of the loop pipeline (7), and a remote automatic regulating valve group (8) is provided on the branch pipeline (9).

5. The device for increasing the methane content in the liquid nitrogen washing inlet gas according to claim 4, characterized in that: The remote automatic regulating valve group (8) comprises a plurality of automatic regulating valves, each of which is electrically connected to a DCS remote control system.

6. The device for increasing the methane content in the liquid nitrogen washing inlet gas according to claim 4, characterized in that: The input end of the branch pipe (9) is connected to the connection between the gas cooler (3) and the flash steam compressor (6) of the low-temperature methanol washing station, the output end of the branch pipe (9) is connected to the liquid nitrogen washing fuel gas pipeline (1), and the output end of the branch pipe (9) is located on the side of the output end of the loop pipe (7) away from the oil-free lubrication gas circulation compressor (2).

7. The device for increasing the methane content in the liquid nitrogen washing inlet gas according to claim 1, characterized in that: The output end of the flash steam compressor (6) of the low-temperature methanol washing station is connected to a low-temperature methanol washing system.

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