A skid-mounted natural gas desulfurization device

Abstract

The present invention discloses a skid-mounted natural gas desulfurization device, which relates to the technical field of natural gas treatment. The technical solution is as follows: It includes an absorption unit, a filtration and aeration unit, and a storage unit. It is characterized in that: The absorption unit includes an absorber. Inside the absorber, a gas distributor, a packing support plate, packing, and a demister are sequentially arranged from bottom to top. A purified natural gas outlet is provided at the top of the absorber, a natural gas inlet is provided on one side of the absorber, a gas connection pipe is provided on one side of the absorber, a degasser is provided at one end of the gas connection pipe, a liquid connection pipe is connected between the absorber and the degasser, a liquid level gauge is provided on one side of the degasser, and a liquid outlet pipe is provided at the bottom of the degasser. The absorption liquid and natural gas both enter the absorber from the bottom. The backwashing of the filter uses "air + absorption liquid" as the medium, and the working condition of the absorption liquid can be intuitively judged by the color of the liquid flowing out through the liquid outlet pipe. It is arranged in a skid-mounted manner, with few devices, low investment cost, and is convenient for control and maintenance.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas treatment, and particularly relates to a skid-mounted natural gas desulfurization device. Background Art

[0002] Since the sulfur content in the associated gas of the oilfield is not too high and the total gas volume is not too large, dry desulfurization is generally used for the associated gas. During the desulfurization process, iron sulfide is generated, which has spontaneous combustion properties and poses a certain risk in oil and gas stations. Moreover, after the dry desulfurization operates for a period of time, solid hazardous waste will be generated, which has an impact on the environment.

[0003] The existing wet desulfurization process has disadvantages such as large investment, complex equipment, many control points, and difficult operation and maintenance. Summary of the Invention

[0004] Therefore, the present invention provides a skid-mounted natural gas desulfurization device to solve the problems of large investment, complex equipment, many control points, and difficult operation and maintenance in the wet desulfurization process.

[0005] To achieve the above object, the present invention provides the following technical solution: A skid-mounted natural gas desulfurization device includes an absorption unit, a filtration and aeration unit, and a storage unit, and is characterized in that: the absorption unit includes an absorber, and inside the absorber, a gas distributor, a packing support plate, packing, and a demister are sequentially arranged from bottom to top. A purified natural gas outlet is provided at the top of the absorber, a natural gas inlet is provided on one side of the absorber, a gas connection pipe is provided on one side of the absorber, a degasser is provided at one end of the gas connection pipe, a liquid connection pipe is connected between the absorber and the degasser, a liquid level gauge is provided on one side of the degasser, and a liquid outlet pipe is provided at the bottom of the degasser. The absorption liquid and the natural gas both enter the absorber from the bottom.

[0006] Preferably, the filtration and aeration unit includes an aerator. Inside the aerator, an aeration element is provided. A regeneration air valve is provided at the connection end of the aeration element, and an air compressor is provided at the connection end of the regeneration air valve. An absorption liquid valve II is connected to one side of the aerator. One end of the absorption liquid valve II is connected to a quartz sand filter. A backwashing air valve is connected to one side of the quartz sand filter, and the backwashing air valve is connected to the air compressor. A backwashing outlet valve is provided at the top of the quartz sand filter. An absorption liquid valve I is connected to the bottom of the aerator. The aerator is an open container. Air enters from the bottom of the aerator and exits from the top. The absorption liquid enters from the lower part and flows out from the middle and upper parts. When the resistance of the quartz sand filter is large, the liquid level of the aerator rises and triggers the liquid level switch on the aerator to control the backwashing of the quartz sand filter, and the start time of the backwashing is determined according to the liquid level of the aerator.

[0007] Preferably, one end of the liquid outlet pipe is connected to an absorption liquid solenoid valve, and the absorption liquid solenoid valve is connected to the absorption liquid valve I.

[0008] Preferably, the storage unit includes a sedimentation tank, an absorption liquid pump is arranged inside the sedimentation tank, the absorption liquid pump is connected to the liquid inlet pipe, two pH meters are arranged on one side of the sedimentation tank, an alkali liquid valve is connected to the top of the sedimentation tank, an alkali liquid tank is arranged at the connection end of the alkali liquid valve, the pH meters provide signals for the alkali addition system, and the liquid level of the sedimentation tank determines whether to supplement water and medicaments.

[0009] Preferably, a liquid level switch is connected to the top of the aerator, an overflow pipe is arranged at the connection end of the liquid level switch, and the overflow pipe is connected to the sedimentation tank.

[0010] Preferably, a backwash outlet valve is arranged at the top of the quartz sand filter, and the backwash outlet valve is connected to the sedimentation tank.

[0011] Preferably, the absorption liquid solenoid valve is sequentially connected with a backwash absorption liquid valve and a post - filtration valve, and the post - filtration valve is connected to the backwash outlet valve.

[0012] Preferably, the quartz sand filter uses solid particles of quartz sand for filtration and is backwashed with absorption liquid and air, and the liquid flow rate does not change for a long time during the filtration and backwashing processes.

[0013] Preferably, a baffle plate is arranged inside the sedimentation tank to play a role in sedimentation.

[0014] A wet desulfurization method for natural gas comprises the following specific steps:

[0015] S1. Natural gas enters the liquid phase space of the absorber through the air distributor. Hydrogen sulfide in the natural gas reacts with the absorption liquid to generate elemental sulfur, and ferric ions in the absorption liquid are reduced to ferrous ions. The gas, liquid, and small - particle elemental sulfur flow upward simultaneously. The liquid and small - particle elemental sulfur enter the degasser through the liquid - phase connecting pipe for degassing. The removed gas enters the gas - phase space inside the absorber through the gas - phase connecting pipe, and the absorption liquid after degassing enters the aerator for regeneration to reduce ferrous ions to ferric ions;

[0016] S2. It enters the filter for filtration. The filtered absorption liquid is aerated and enters the sedimentation tank for sedimentation, and then is pressurized by the absorption liquid pump and enters the absorption liquid;

[0017] S3. The alkali addition system can quantitatively add alkali liquid when the pH value of the absorption liquid is lower than the set value.

[0018] The embodiments of the present invention have the following advantages:

[0019] Natural gas enters the absorber through the air distributor, disperses the natural gas into small bubbles, and the filler layer prevents the bubbles from growing and increases the residence time of the bubbles in the absorber, thereby improving the absorption effect of the absorption liquid on hydrogen sulfide. It is possible to intuitively judge whether the absorption liquid is working properly by the color of the liquid flowing out through the liquid outlet pipe;

[0020] The backwashing of the filter uses "air + absorbent liquid" as the medium, and the flow rate of the absorbent liquid is not changed during the backwashing process, so as to stabilize the precipitation effect of the precipitation tank. The precipitation tank is provided with a baffle to increase the residence time of the absorbent liquid in the tank and play a precipitation role. The precipitation tank is provided with a pH detector, and the amount of alkali added is controlled according to this value, so as to selectively absorb hydrogen sulfide without absorbing carbon dioxide. It is arranged in a skid-mounted manner, with few equipment and low investment cost, which is convenient for control and maintenance. Brief Description of the Drawings

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can be obtained according to the provided drawings.

[0022] The structures, ratios, sizes, etc. shown in this specification are only used to cooperate with the content disclosed in the specification for those who are familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the efficacy and the purpose that the present invention can achieve, should still fall within the scope that the technical content disclosed by the present invention can cover.

[0023] Figure 1 It is the overall structure schematic diagram provided by the present invention.

[0024] In the figure: 100, absorption unit; 101, absorber; 102, gas distributor; 103, packing support plate; 104, packing; 105, demister; 106, degasser; 107, purified natural gas outlet; 108, gas connection pipe; 109, liquid connection pipe; 110, liquid outlet pipe; 111, liquid inlet pipe; 112, natural gas inlet; 113, absorbent liquid solenoid valve; 114, liquid level gauge; 200, filtration aeration unit; 201, aerator; 202, regeneration air valve; 203, aeration element; 204, absorbent liquid valve 1; 205, absorbent liquid valve 2; 206, liquid level switch; 207, quartz sand filter; 208, backwashing absorbent liquid valve; 209, post-filter valve; 210, backwashing air valve; 211, backwashing outlet valve; 212, air compressor; 213, overflow pipe; 300, storage unit; 301, precipitation tank; 302, pH meter; 303, absorbent liquid pump; 304, alkali liquid tank; 305, alkali liquid valve. Detailed Embodiments

[0025] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0026] Referring to the attached Figure 1 , a skid-mounted natural gas desulfurization device provided by the present invention includes an absorption unit 100, a filtration aeration unit 200, and a storage unit 300. The absorption unit 100 includes an absorber 101. Inside the absorber 101, a gas distributor 102, a packing support plate 103, packing 104, and a demister 105 are sequentially arranged from bottom to top. A purified natural gas outlet 107 is provided at the top of the absorber 101. A natural gas inlet 112 is provided on one side of the absorber 101. A gas connection pipe 108 is provided on one side of the absorber 101. A degasser 106 is provided at one end of the gas connection pipe 108. A liquid connection pipe 109 is connected between the absorber 101 and the degasser 106. A liquid level gauge 114 is provided on one side of the degasser 106. A liquid outlet pipe 110 is provided at the bottom of the degasser 106. The absorption liquid and natural gas both enter the absorber 101 from the bottom;

[0027] In this embodiment, the absorber 101 prevents the bubbles of natural gas from aggregating and growing in the absorption liquid through the packing layer, increasing the gas-liquid contact area. Natural gas enters the absorber 101 from the natural gas inlet 112, is dispersed into small bubbles by the gas distributor 102 and reacts with the absorption liquid, reducing the trivalent iron in the absorption liquid to divalent iron, and at the same time reducing hydrogen sulfide to elemental sulfur. The natural gas passes through the packing 104, preventing the bubbles from aggregating and growing, increasing the upward floating distance of the natural gas, and increasing the reaction time of the chemical reaction. Most of the natural gas enters the gas phase space, and a small part enters the liquid connection pipe 109, where gas-liquid separation occurs in the degasser 106, and then returns to the gas phase space of the absorber 101 through the gas connection pipe 108. The natural gas passes through the demister 105 and the purified natural gas outlet 107, and after purification, enters the next process. The absorption liquid enters the absorber 101, reacts with the natural gas coming out of the gas distributor 102, then passes through the packing 104 and the liquid connection pipe 109 into the degasser 106. The degassed absorption liquid controls the liquid outlet flow according to the signal of the liquid level gauge 114 of the degasser 106 through the absorption liquid solenoid valve 113. The absorption liquid coming out of the absorption liquid solenoid valve 113 enters the aerator 201 through the absorption liquid valve 1 204 and reacts with air to oxidize the divalent iron to trivalent iron;

[0028] Among them, in order to achieve the purpose of aeration, the present device adopts the following technical solution: The filtration and aeration unit 200 includes an aerator 201. An aeration element 203 is provided inside the aerator 201. A regeneration air valve 202 is provided at the connection end of the aeration element 203. An air compressor 212 is provided at the connection end of the regeneration air valve 202. A second absorption liquid valve 205 is connected to one side of the aerator 201. One end of the second absorption liquid valve 205 is connected to a quartz sand filter 207. A backwash air valve 210 is connected to one side of the quartz sand filter 207. The backwash air valve 210 is connected to the air compressor 212. A backwash outlet valve 211 is provided at the top of the quartz sand filter 207. A first absorption liquid valve 204 is connected to the bottom of the aerator 201. The aerator 201 is an open container. Air enters from the bottom of the aerator 201 and exits from the top. The absorption liquid enters from the lower part and flows out from the middle upper part. When the resistance of the quartz sand filter 207 is large, the liquid level of the aerator 201 rises and triggers the liquid level switch 206 on the aerator 201 to control the backwash of the quartz sand filter 207. The start time of the backwash is determined according to the liquid level of the aerator 201. One end of the liquid outlet pipe 110 is connected to an absorption liquid solenoid valve 113. The absorption liquid solenoid valve 113 is connected to the first absorption liquid valve 204. The quartz sand filter 207 is filtered with solid particles such as quartz sand and backwashed with absorption liquid and air. During the filtration and backwash processes, the liquid flow does not change for a long time. The first absorption liquid valve 204, the regeneration air valve 202, and the post-filter valve 209 are closed. The backwash absorption liquid valve 208, the backwash air valve 210, and the backwash outlet valve 211 are opened. The large-particle sulfur washed out enters the precipitation in the precipitation tank 301. Sulfur accumulates at the bottom of the precipitation tank 301 and is cleaned regularly. During normal operation, air is dispersed into small bubbles through the regeneration air valve 202 and the aeration element 203, reacts with the absorption liquid, and is discharged outside through the overflow pipe 213. During backwashing, air enters the quartz sand filter 207 through the backwash air valve 210 to disturb the filter layer, so that the filter cake on the upper part enters the absorption precipitation tank 301 together with air and the backwash absorption liquid through the backwash outlet valve 211;

[0029] Among them, in order to achieve the purpose of quantitatively adding lye, the present device adopts the following technical solutions: The storage unit 300 includes a precipitation tank 301. Inside the precipitation tank 301, there is an absorption liquid pump 303. The absorption liquid pump 303 is connected to the liquid inlet pipe 111. On one side of the precipitation tank 301, there are two pH meters 302. The top of the precipitation tank 301 is connected to a lye valve 305. The connection end of the lye valve 305 is provided with a lye tank 304. The pH meters 302 provide signals for the lye addition system. The liquid level of the precipitation tank 301 determines whether to supplement water and chemicals. The top of the aerator 201 is connected to a liquid level switch 206. The connection end of the liquid level switch 206 is provided with an overflow pipe 213. The overflow pipe 213 is connected to the precipitation tank 301. The top of the quartz sand filter 207 is provided with an anti-wash outlet valve 211. The anti-wash outlet valve 211 is connected to the precipitation tank 301. The absorption liquid solenoid valve 113 is successively connected with an anti-wash absorption liquid valve 208 and a post-filtration valve 209. The post-filtration valve 209 is connected to the anti-wash outlet valve 211. Inside the precipitation tank 301, there is a baffle plate, which plays a role in precipitation. When the pH meter 302 in the precipitation tank 301 detects that the pH is too low, the lye valve 305 is opened for a period of time and then closed regularly;

[0030] A wet natural gas desulfurization method, the specific steps are as follows:

[0031] S1. Natural gas enters the absorber 101 from the natural gas inlet 112, is dispersed into small bubbles by the air distributor 102 and reacts with the absorption liquid, reducing the trivalent iron in the absorption liquid to divalent iron, and at the same time reducing hydrogen sulfide to elemental sulfur. The natural gas passes through the packing 104, which prevents the bubbles from aggregating and growing, increases the upward floating distance of the natural gas, and increases the time for chemical reactions. Most of the natural gas enters the gas phase space, and a small part enters the liquid connection pipe 109, is separated from gas and liquid in the degasser 106, and then returns to the gas phase space of the absorber 101 through the gas connection pipe 108. The natural gas passes through the demister 105 and the purified natural gas outlet 107, and after purification, it enters the next process. The absorption liquid enters the absorber 101, reacts with the natural gas coming out of the air distributor 102, then passes through the packing 104 and the liquid connection pipe 109 and enters the degasser 106. The degassed absorption liquid controls the liquid outlet flow through the absorption liquid solenoid valve 113 according to the signal of the liquid level gauge 114 in the degasser 106. The absorption liquid coming out of the absorption liquid solenoid valve 113 enters the aerator 201 through the absorption liquid valve one 204 and reacts with air, oxidizing the divalent iron to trivalent iron, then enters the quartz sand filter 207 through the absorption liquid valve two 205, then passes through the post-filtration valve 209 and enters the precipitation tank 301. The absorption liquid is further precipitated in the precipitation tank 301, and then enters the absorber 101 after being circulated by the absorption liquid pump 303. The top of the aerator 201 is provided with an overflow pipe 213 and a liquid level switch 206. When the resistance of the quartz sand filter 207 increases, it enters the precipitation tank 301 through the overflow pipe 213 and triggers the liquid level switch 206 to start the backwashing process;

[0032] S2. During backwashing, the absorption liquid valve 1 - 204, the regeneration air valve 202, and the post - filtration valve 209 are closed, while the backwash absorption liquid valve 208, the backwash air valve 210, and the backwash outlet valve 211 are opened. The large - particle sulfur washed out enters the sedimentation in the sedimentation tank 301, and the sulfur accumulates at the bottom of the sedimentation tank 301 and is cleaned regularly. During normal operation, air is dispersed into small bubbles by the aeration element 203 from the regeneration air valve 202, reacts with the absorption liquid, and is discharged outside through the overflow pipe 213. During backwashing, air enters the quartz sand filter 207 through the backwash air valve 210 to disturb the filter layer, so that the filter cake on the upper part enters the sedimentation tank 301 together with air and the backwash absorption liquid through the backwash outlet valve 211;

[0033] S3. When the pH meter 302 in the sedimentation tank 301 detects that the pH is too low, the alkali liquid valve 305 is opened for a period of time and then closed regularly.

[0034] As described above, it is only a preferred embodiment of the present invention. Any person skilled in the art may modify the present invention by using the technical solutions described above or modify it into an equivalent technical solution. Therefore, any simple modification or equivalent replacement made according to the technical solutions of the present invention falls within the scope of protection required by the present invention.

Claims

1. A skid-mounted natural gas desulfurization device, comprising an absorption unit (100), a filtration and aeration unit (200) and a storage unit (300), characterized in that: The absorption unit (100) includes an absorber (101). Inside the absorber (101), a gas distributor (102), a packing support plate (103), packing (104), and a demister (105) are successively arranged from bottom to top. A purified natural gas outlet (107) is provided at the top of the absorber (101). A natural gas inlet (112) is provided on one side of the absorber (101). A gas connection pipe (108) is provided on one side of the absorber (101). A degasser (106) is provided at one end of the gas connection pipe (108). A liquid connection pipe (109) is connected between the absorber (101) and the degasser (106). A liquid level gauge (114) is provided on one side of the degasser (106). A liquid outlet pipe (110) is provided at the bottom of the degasser (106). The absorption liquid and natural gas both enter the absorber (101) from the bottom; The filtration and aeration unit (200) includes an aerator (201). An aeration element (203) is provided inside the aerator (201). A regeneration air valve (202) is provided at the connection end of the aeration element (203). An air compressor (212) is provided at the connection end of the regeneration air valve (202). An absorption liquid valve II (205) is connected to one side of the aerator (201). A quartz sand filter (207) is connected to one end of the absorption liquid valve II (205). A backwash air valve (210) is connected to one side of the quartz sand filter (207). The backwash air valve (210) is connected to the air compressor (212). A backwash outlet valve (211) is provided at the top of the quartz sand filter (207). An absorption liquid valve I (204) is connected to the bottom of the aerator (201). The aerator (201) is an open container. Air enters from the bottom of the aerator (201) and exits from the top. The absorption liquid enters from the lower part and flows out from the middle upper part. When the resistance of the quartz sand filter (207) is large, the liquid level of the aerator (201) rises, triggering a liquid level switch (206) on the aerator (201) to control the backwash of the quartz sand filter (207). The start time of the backwash is determined according to the liquid level of the aerator (201). One end of the liquid outlet pipe (110) is connected to an absorption liquid solenoid valve (113). The absorption liquid solenoid valve (113) is connected to the absorption liquid valve I (204). The storage unit (300) includes a sedimentation tank (301). An absorption liquid pump (303) is provided inside the sedimentation tank (301). The absorption liquid pump (303) is connected to a liquid inlet pipe (111). Two pH meters (302) are provided on one side of the sedimentation tank (301). An alkali liquid valve (305) is connected to the top of the sedimentation tank (301). An alkali liquid tank (304) is provided at the connection end of the alkali liquid valve (305). The pH meters (302) provide signals for the alkali addition system. The liquid level of the sedimentation tank (301) determines whether to supplement water and chemicals. A baffle is provided inside the sedimentation tank (301) to play a role in sedimentation.

2. The skid-mounted natural gas desulfurization device according to claim 1, characterized in that: A liquid level switch (206) is connected to the top of the aerator (201). An overflow pipe (213) is provided at the connection end of the liquid level switch (206), and the overflow pipe (213) is connected to the sedimentation tank (301).

3. The skid-mounted natural gas desulfurization device according to claim 1, characterized in that: A backwash outlet valve (211) is provided at the top of the quartz sand filter (207), and the backwash outlet valve (211) is connected to the sedimentation tank (301).

4. The skid-mounted natural gas desulfurization device according to claim 3, characterized in that: The absorption liquid solenoid valve (113) is sequentially connected with a backwash absorption liquid valve (208) and a post-filtration valve (209), and the post-filtration valve (209) is connected to the backwash outlet valve (211).

5. The skid-mounted natural gas desulfurization device according to claim 1, wherein: The quartz sand filter (207) filters using solid particles such as quartz sand, and is backwashed with absorption liquid and air. During the filtration and backwashing processes, the liquid flow rate does not change for a long time.

6. A wet natural gas desulfurization method, based on a skid-mounted natural gas desulfurization device described in any one of claims 1-5, characterized in that: The specific steps are as follows: S1. Natural gas enters the liquid phase space of the absorber through the air distributor. Hydrogen sulfide in the natural gas reacts with the absorption liquid to generate elemental sulfur, and ferric iron in the absorption liquid is reduced to ferrous iron. The gas, liquid, and small particle elemental sulfur flow upward simultaneously. The liquid and small particle elemental sulfur enter the degasser through the liquid connection pipe for degassing. The removed gas enters the gas phase space inside the absorber through the gas connection pipe. The degassed absorption liquid enters the aerator for regeneration to reduce ferrous iron to ferric iron; S2. It enters the filter for filtration. The filtered absorption liquid is aerated and enters the sedimentation tank for sedimentation, and then is pressurized by the absorption liquid pump to enter the absorption liquid; S3. The alkali addition system can quantitatively add alkali solution when the pH value of the absorption liquid is lower than the set value.

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