Device capable of reducing water carried by shift gas

Abstract

The utility model relates to a device capable of reducing water carried by shift gas, which comprises a flow guide pipe, one end of the flow guide pipe is connected with a gas outlet end of a shift gas pipeline, the other end of the flow guide pipe is sealed and is provided with a plurality of straight pipe distributors along the circumferential direction, the plurality of straight pipe distributors are radially distributed along the radial direction, and one ends of the plurality of straight pipe distributors far away from the flow guide pipe are sealed. Gas distribution holes are formed in the lower side walls of the plurality of straight pipe distributors; after entering the ammonia pre-washing tower, the converted gas uniformly flows out from the gas distribution holes in the straight pipe distributor, the gas distribution is wide, the gas-liquid contact surface is increased, the washing effect is ensured, and meanwhile, the sleeve inserted into the liquid at the bottom of the ammonia pre-washing tower is detached, so that the pressure difference between the converted gas and the liquid in the tower is reduced; the flow velocity of the shift gas flowing out of the liquid level is more uniform, the liquid carrying amount is less, the energy consumption of a subsequent purification device is favorably reduced, and the operation stability of the subsequent purification device is improved.

Description

Technical Field

[0001] This utility model relates to the field of gas purification technology, and in particular to a device that can reduce water carryover in gas. Background Technology

[0002] Shift gas is a mixed gas produced by the water-gas shift reaction (CO + H2O → CO2 + H2). Its core function is to convert carbon monoxide (CO) in the feedstock gas (such as coal-to-syngas or natural gas reforming gas) into hydrogen (H2), while simultaneously producing carbon dioxide (CO2). Hydrogen is the main product of the shift gas, and it needs to be purified before being used in subsequent processes. The mixed gas produced after the water-gas shift reaction contains other impurities besides carbon dioxide (ammonia, benzene, phenol, coal dust, HCN, hydrocarbons, H2S, COS). A common purification process involves using a cooling device to cool the high-temperature shift gas produced by the water-gas shift reaction. The shift gas, cooled to 40℃ and 3.30MPa, enters the ammonia pre-washing tower to remove ammonia. To prevent the accumulation of ammonia in the feed gas during the methanol cycle and to remove trace amounts of benzene, phenol, and dust, feed water from a medium-pressure boiler at 140℃ and 6.50MPa(g) is used. The feed water is cooled to 38℃ by a boiler water cooler and then enters the ammonia pre-washing tower for washing. The shift gas (CO2+H2) after ammonia removal is sent from the top of the tower to the feed gas cooler. The cooled shift gas has a temperature of -17℃ and enters the methanol washing tower to remove HCN, benzene, hydrocarbons, H2S, COS, and CO2. The purified shift gas is then used in subsequent processes.

[0003] To enhance the washing effect, the existing technology employs the following structure: the shift gas enters the ammonia pre-washing tower through a guide pipe, with one end of the guide pipe facing downwards and inserted to the bottom of the ammonia pre-washing tower. Several air distribution holes are set on the pipe immersed in the pre-washing liquid, and a sleeve is set around this part of the pipe. One end of the sleeve above the air distribution holes is sealed to the pipe, and the other end is open and inserted to the bottom of the ammonia pre-washing tower. When the shift gas enters the ammonia pre-washing tower, it flows out from the air distribution holes of the pipe at the bottom of the tower and the open end of the sleeve. Because the pipe with air distribution holes is surrounded by a sleeve, when the gas flow rate increases, it is easy to cause a local pressure increase between the sleeve and the pipe. The shift gas passes through the boiler water surface, causing fluctuations in the liquid level of the ammonia pre-washing tower. The shift gas carries liquid severely, resulting in flooding.

[0004] In actual production, a large amount of water carried in the shift gas can easily cause blockage of the feed gas heat exchanger, forcing the unit to shut down. Water introduced into the downstream system increases the operating load of the pre-wash system and increases the unit's energy consumption. If this water enters the main wash system, it will affect the absorption of CO2 by methanol and affect the safe and stable operation of the unit. Utility Model Content

[0005] The purpose of this invention is to provide a device that can reduce water carryover in the alternating gas, thereby solving the aforementioned problems in the prior art.

[0006] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0007] A device for reducing water carryover in changeover gas includes a guide pipe, one end of which is connected to the outlet of the changeover gas pipeline, and the other end is sealed and has a plurality of straight pipe distributors arranged in a circumferential direction. The plurality of straight pipe distributors are radially distributed in a radial direction, and the ends of the plurality of straight pipe distributors away from the guide pipe are sealed. The lower sidewalls of the plurality of straight pipe distributors are provided with air distribution holes.

[0008] The beneficial effects of this invention are as follows: After the shift gas enters the ammonia pre-washing tower, the gas flows out evenly from the gas distribution holes on the straight pipe distributor, resulting in a wide gas distribution and increasing the gas-liquid contact surface, thus ensuring the washing effect. At the same time, the sleeve inserted under the liquid at the bottom of the ammonia pre-washing tower is removed, which reduces the pressure difference between the shift gas and the liquid in the tower, making the flow rate of the shift gas more uniform when it flows out from below the liquid surface, with less liquid carried over. This helps to reduce the energy consumption of the subsequent purification unit and improves the operational stability of the subsequent purification unit.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, several straight pipe distributors are set at equal angles.

[0011] The further beneficial effect of adopting the above is that the arrangement of several straight pipe distributors at equal angles further improves the uniformity of the flow velocity when the shift gas flows out from below the liquid surface.

[0012] Furthermore, the outer diameter of the straight pipe distributor is 400 mm, and the diameter of the air distribution hole is 50 mm.

[0013] The further beneficial effects of adopting the above are: under the same opening ratio, the resistance coefficient of a 50mm orifice is reduced by about 40% compared to a small orifice, and the flow coefficient of a single orifice is increased, making it suitable for high-velocity operating conditions; the 50mm orifice is more adaptable to dusty gas, effectively preventing clogging; in specific implementation, 50mm orifices can be obtained by flame cutting or mechanical drilling, which is 80% more efficient than dense small orifices, easier to process, and can effectively reduce processing costs.

[0014] Furthermore, both the guide tube and the straight pipe distributor are made of 316L austenitic stainless steel.

[0015] The further beneficial effects of adopting the above are: the shift gas contains corrosive gases such as H2S and CO2, and the prewash liquid contains NH4. + It is acidic, and 316L austenitic stainless steel is better able to adapt to corrosive environments and has better stability. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of one embodiment of the present utility model;

[0017] The attached diagram lists the components represented by each number as follows:

[0018] 1. Guide pipe, 11. Straight pipe distributor, 111. Air distribution hole, 12. Flange. Detailed Implementation

[0019] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0020] Example 1

[0021] like Figure 1 As shown, a device for reducing water carryover in the changeover gas includes a guide pipe 1. One end of the guide pipe 1 is connected to the outlet end of the changeover gas pipeline, and the other end is sealed and a plurality of straight pipe distributors 11 are arranged in a circumferential direction. The plurality of straight pipe distributors 11 are radially distributed in a radial direction. The ends of the plurality of straight pipe distributors 11 away from the guide pipe 1 are sealed, and air distribution holes 111 are provided on the lower sidewalls of the plurality of straight pipe distributors 11.

[0022] After the shifted gas enters the ammonia pre-washing tower, the gas flows out evenly from the gas distribution holes 111 on the straight pipe distributor 11. The gas distribution is wide, which increases the gas-liquid contact surface and ensures the washing effect. At the same time, the sleeve inserted under the liquid at the bottom of the ammonia pre-washing tower is removed, which reduces the pressure difference between the shifted gas and the liquid in the tower. This makes the flow rate of the shifted gas more uniform when it flows out from below the liquid surface, and the amount of liquid carried is less. This helps to reduce the energy consumption of the subsequent purification unit and improve the operational stability of the subsequent purification unit.

[0023] Example 2

[0024] This embodiment is a further improvement on embodiment 1, as detailed below:

[0025] Several straight pipe distributors 11 are set at equal angles; the equal angle setting of the straight pipe distributors 11 further improves the uniformity of the flow velocity when the change gas flows out from below the liquid surface.

[0026] In practice, there are 6 straight pipe distributors 11, set at equal angles of 60°.

[0027] The straight pipe distributor 11 has an outer diameter of 400 mm, and the air distribution hole 111 has a diameter of 50 mm. Under the same opening ratio, the resistance coefficient of the 50 mm hole is reduced by about 40% compared with the small hole, and the single hole flow coefficient is improved, making it suitable for high air velocity conditions. The 50 mm hole is more adaptable to dusty gas and effectively prevents clogging. In specific implementation, the 50 mm hole can be flame cut or mechanically drilled, which is 80% more efficient than dense small holes, easier to process, and can effectively reduce processing costs.

[0028] Both the guide pipe 1 and the straight pipe distributor 11 are made of 316L austenitic stainless steel. The shift gas contains corrosive gases such as H2S and CO2, and the prewash liquid contains NH4. + It is acidic, and 316L austenitic stainless steel is better able to adapt to corrosive environments and has better stability.

[0029] The straight pipe distributor 11 is welded and fixed to the guide pipe 1. The welded connection forms a continuous whole through metal fusion, completely eliminating potential leakage points such as loose flange / threaded connections, and is especially suitable for scenarios containing toxic / corrosive media such as H2S and NH3; the welded joint can withstand higher internal pressures such as above 5MPa, and better adapts to the pressure fluctuations of the gas transmission; the welded joint has a high natural frequency, is not prone to fatigue cracks due to fluid pulsation or mechanical vibration, has better stability, and has no protruding flange or threaded structure, reducing the scouring and wear of the pipe wall by solid impurities in the pre-washing liquid.

[0030] In practice, 316L austenitic stainless steel has good welding performance. The straight pipe distributor 11 and the guide pipe 1 can be welded by argon arc welding and then pickled and passivated after welding.

[0031] Example 3

[0032] This embodiment is a further improvement on embodiment 2, as detailed below:

[0033] One end of the guide pipe 1 is equipped with a flange 12; the guide pipe 1 is connected to the outlet end of the gas conversion pipeline through the flange joint, which is convenient for disassembly and facilitates the later inspection and maintenance of the interface.

[0034] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A device for reducing water carryover in shifted gases, characterized in that, It includes a guide pipe (1), one end of which is connected to the outlet end of the gas exchange pipeline, and the other end is sealed and a plurality of straight pipe distributors (11) are arranged in a circumferential direction. The plurality of straight pipe distributors (11) are radially distributed in a radial direction. The end of the plurality of straight pipe distributors (11) away from the guide pipe (1) is sealed, and the lower side wall of the plurality of straight pipe distributors (11) is provided with air distribution holes (111).

2. The device for reducing water carryover in shift gas according to claim 1, characterized in that, Several of the straight pipe distributors (11) are set at equal angles.

3. The device for reducing water carryover in shift gas according to claim 2, characterized in that, The outer diameter of the straight pipe distributor (11) is 400 mm, and the diameter of the air distribution hole (111) is 50 mm.

4. The device for reducing water carryover in shift gas according to claim 3, characterized in that, The guide pipe (1) and the straight pipe distributor (11) are both made of 316L austenitic stainless steel.

5. The device for reducing water carryover in shift gas according to claim 4, characterized in that, The straight pipe distributor (11) is welded and fixed to the guide pipe (1).

6. The device for reducing water carryover in shift gas according to claim 5, characterized in that, A flange (12) is provided at one end of the guide pipe (1).

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