Method for treating gas containing H2S and CO2

Abstract

The present invention belongs to the field of gas separation, and specifically relates to a method for step-by-step treatment of gas containing H2S and CO2. The method comprises the following steps: A: throttling the gas containing H2S and CO2 to be treated to obtain gas I; B: pre-absorbing gas I with a reduction liquid to obtain pre-absorbed gas II, and throttling the pre-absorbed gas II to obtain gas III; C: deeply absorbing gas III with a reduction liquid to obtain deeply absorbed gas IV, and separating the deeply absorbed gas IV by mist capture to obtain gas V and liquid I, and liquid I is reused as a reduction liquid. The method of the present invention is not only applicable to the oil and gas field site containing H2S and CO2 gas, but also applicable to the efficient purification treatment of H2S and CO2 gas generated by an experimental simulation device. The technical scheme of the present invention can reduce the pollution of H2S to the environment, and reduce the impact of the release of CO2 gas on the environment and climate change.

Description

Technical Field

[0001] The invention belongs to the field of gas separation, and in particular relates to a method for step-by-step processing of gas containing H2S and CO2. Background Art

[0002] In the production of oil and gas fields, H2S and CO2 are often produced with oil and gas. H2S is toxic and direct discharge will pollute the environment. H2S and CO2 will also corrode devices and equipment. When the concentration of H2S in the environment reaches 10ppm, the eyes and respiratory tract begin to be irritated to a certain extent. When the concentration rises to 20-300ppm, it will cause dizziness, headache, temporary loss of smell and edema. When the concentration rises to 300-500ppm, short-term exposure will also be life-threatening and require timely treatment. Therefore, it is necessary to effectively treat the output gas containing H2S and CO2 to meet the emission requirements and corrosion control requirements.

[0003] In addition, after conducting simulated H2S and CO2 corrosion experiments in the laboratory using high-temperature and high-pressure autoclaves, normal-pressure closed devices, and corrosion loops, the gases after the experiments also need to be purified to meet emission requirements.

[0004] In view of the toxicity of H2S, more attention is paid to H2S removal technology at home and abroad, and relatively few reports are on the technology of removing H2S and CO2 at the same time. Desulfurization technology is mainly divided into dry desulfurization and wet desulfurization. Dry desulfurization usually uses granular or powdered desulfurizers to adsorb, absorb or oxidize H2S, but dry desulfurizers are difficult to regenerate and require high reaction temperatures. Wet desulfurization uses solvents with H2S absorption properties to absorb or absorb and oxidize H2S. In fact, after CO2 reacts with alkaline substances in the desulfurizer, it will affect the acidity and alkalinity of the system and consume the desulfurization liquid components. Therefore, the absorption performance of the treatment solution containing H2S and CO2 gases is required to be higher.

[0005] CN205659554U discloses a novel hydrogen sulfide tail gas purification treatment device, which treats H2S tail gas through two storage tanks connected in series. Multi-layer baffles with holes are alternately arranged inside the storage tank to extend the flow time of tail gas in the storage tank and improve the H2S purification treatment efficiency; a spray port is arranged on the top of the storage tank. However, the device is only suitable for hydrogen sulfide tail gas treatment, and the specific composition of the treatment solvent is not mentioned.

[0006] CN106381182B discloses a liquid absorbent for removing hydrogen sulfide and its application. The absorbent is composed of the following components in mass percentage: 30-50% of a mixture of hexahydrotriazine compounds and pyridine compounds, 10-20% of acetonitrile, and the balance is water. The hydrogen sulfide absorbent can quickly and efficiently absorb hydrogen sulfide in the gas produced in the wellbore. The product is stable and soluble in water. It has a good effect on wellbores with low hydrogen sulfide gas content, reduces the corrosion of hydrogen sulfide to the wellbore pipe column, and protects on-site employees from hydrogen sulfide poisoning. However, hexahydrotriazine compounds are mainly suitable for situations with lower concentrations of H2S (such as less than 300ppm), and are not effective when the H2S content is higher. In addition, the pH value of produced water from general oil and gas fields is 5-7, the pH value of hexahydrotriazine compounds (1% aqueous solution) is 9.5-11.5, and pyridine compounds are also alkaline. Such alkaline absorbents added directly into the wellbore will cause the pH value of the produced water to increase and change the properties of the produced water. For produced water with high mineralization, or produced water with high content of scaling ions such as calcium and magnesium, the scaling tendency of the produced water will be significantly increased, and a scale layer will be formed in the wellbore. In severe cases, the wellbore will be blocked, and small pore corrosion is prone to occur on the metal surface under the scale layer.

[0007] CN109381981A discloses a novel desulfurizing agent and a process for oxidative removal of hydrogen sulfide. The desulfurizing agent includes an iron-based ionic liquid and a cosolvent, and preferably also includes a defoamer. The weight ratio of the iron-based ionic liquid, the cosolvent and the defoamer is 200:(1-80):(1-60). The iron-based ionic liquid is an organic amine type iron-based ionic liquid, such as triethylamine hydrochloride iron-based ionic liquid Et3NHFeCl4, and the cosolvent is selected from any one or more of N,N-dimethylacetamide, N,N-dimethylformamide, tributyl phosphate, and N-methylpyrrolidone propylene carbonate. The defoamer is selected from any one or more of tributyl phosphate, silicone defoamer, polyether defoamer, and polyether composite silicone defoamer. The iron-based ionic liquid oxidizes H2S into sulfur. However, this desulfurization process is actually a complex iron desulfurization process, which is not suitable for the treatment of gases with high H2S content. In addition, the rich liquid formed by the reaction of the complex iron solution with H2S during the treatment process has high viscosity, which reduces the gas-liquid mass transfer efficiency and limits the conversion rate of hydrogen sulfide. Another prominent problem of this process is the sulfur blockage problem in the equipment, which affects production efficiency and easily causes safety problems. Summary of the invention

[0008] The purpose of the present invention is to overcome the problem of low efficiency in treating H2S and CO2-containing gases in the prior art, and to provide a method for treating H2S and CO2-containing gases.

[0009] In order to achieve the above object, the present invention provides a method for treating a gas containing H2S and CO2, the method comprising the following steps:

[0010] A: The gas containing H2S and CO2 to be treated is throttled to obtain gas I;

[0011] B: pre-absorb gas I with reducing liquid to obtain pre-absorbed gas II, and then throttle the pre-absorbed gas II to obtain gas III;

[0012] C: Gas III is deeply absorbed by the reduction liquid to obtain deeply absorbed gas IV. The deeply absorbed gas IV is separated by mist capture to obtain gas V and liquid I. Liquid I is reused as the reduction liquid.

[0013] Through the above technical solution, the present invention has the following beneficial effects:

[0014] The existing technology mainly achieves the purpose of removing H2S by combining desulfurizers with treatment devices. It mainly desulfurizes natural gas containing H2S or tail gas containing H2S. The treatment effect is not high. The H2S concentration in the treated gas is difficult to reach the emission limit of 10mg / m 3 In addition, these devices and methods are not designed to treat gases containing H2S and CO2. When the gas contains both H2S and CO2, CO2 will react with the alkaline substances in the desulfurizer, which will affect the acidity and alkalinity of the system and consume the desulfurization liquid components, thus increasing the difficulty of desulfurization and decarbonization.

[0015] In a preferred embodiment, the organic amine in the abatement agent of the present invention can react with hydrogen sulfide and carbon dioxide to form bound amine (R3NH + ); The inorganic base in the present invention has two functions, one is that it can directly react with hydrogen sulfide and carbon dioxide; the other is that it can bind the amine (R3NH + ) is converted into free amines, which can then react with hydrogen sulfide and carbon dioxide to achieve the purpose of activation and recycling. The promoter of the present invention can further promote the reaction of organic amines and inorganic bases with hydrogen sulfide and carbon dioxide, thereby increasing the reduction effect of the reduction liquid. In combination with the device for treating gases containing H2S and CO2 of the present invention, the concentrations of H2S and CO2 are gradually reduced. The reduction agent of the present invention has a certain corrosion inhibition effect on the device, and the device and method of the present invention have a wide range of applications and high treatment efficiency.

[0016] The device and method for step-by-step treatment of H2S and CO2-containing gases provided by the present invention are not only applicable to oil and gas fields containing H2S and CO2 gases, but also applicable to the efficient purification of H2S and CO2-containing gases produced by experimental simulation devices. The technical solution of the present invention can reduce the pollution of H2S to the environment and reduce the impact of the release of CO2 gas on the environment and climate change; the H2S content in the treated gas is less than 10mg / m 3The requirements of the company were met, solving the problems of low efficiency, foaming and corrosion in the treatment of gases containing H2S and CO2. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of a device for treating gas containing H2S and CO2 according to a specific embodiment of the present invention;

[0018] Figure 2 It is a structural schematic diagram of the deep absorption tower of the present invention;

[0019] Figure 3 It is a schematic structural diagram of the guide vane and the second hollow tube of the present invention;

[0020] Figure 4 It is a schematic diagram of the structure of the gas source area when the device of the present invention is used for experimental simulation.

[0021] Description of Reference Numerals

[0022] 1 Gas source introduction mechanism 2 Pre-absorption tower

[0023] 3 Deep absorption tower 4 Deep separation tower

[0024] 5 Reduction fluid storage tank 6-1 One-way pressure reducing valve

[0025] 7-1 Large-diameter gas pipeline 8-1 Small-diameter gas pipeline

[0026] 2-1 Gas distribution structure 2-2 Reduction liquid spray pipe

[0027] 31 H2S concentration measuring instrument 3-1 Gas distributor

[0028] 3-2 Hollow reducing liquid sprayer 3-21 Multi-hole spray head

[0029] 3-3 Liquid receiving tube 3-4 First hollow tube

[0030] 3-5 deflector 3-6 mist collector

[0031] 3-7 Gas exhaust pipe 41 flame arrester

[0032] 42 Burner 43 Exhaust pipe

[0033] 4-1 Guide vane 4-2 Second hollow tube

[0034] 4-3 Support plate 4-4 Inclined plate

[0035] 4-5 Flow blocker 4-6 Porous mist collector

[0036] 51 Acid storage tank 52 Alkali storage tank

[0037] 53 Reduction fluid circulation pump 5-1 Agitator

[0038] 5-2 pH meter 9 next door

[0039] 9-1 First air inlet pipe 9-2 First check valve

[0040] 9-3 First air pump 9-1-1 Second air inlet pipe

[0041] 9-2-1 Second one-way valve 9-3-1 Second air pump

[0042] 6-2 One-way pressure reducing valve 7-2 Large diameter gas pipeline

[0043] 8-2 Small-diameter gas pipeline DETAILED DESCRIPTION

[0044] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0045] In the present invention, "I, II, III, IV, V, VI, VII, VIII" are only used to distinguish the products obtained in different steps and do not play a limiting role.

[0046] In the present invention, unless otherwise specified, directional words such as "up, down, bottom, top" generally refer to the up, down, bottom, top shown in the reference drawings; "inside and outside" refer to the inside and outside relative to the outline of each device itself.

[0047] In the present invention, the pressure refers to the gauge pressure.

[0048] The present invention provides a method for treating a gas containing H2S and CO2, the method comprising the following steps:

[0049] A: The gas containing H2S and CO2 to be treated is throttled to obtain gas I, and the flow rate of gas I is 0.1-1.5m / s;

[0050] B: Pre-absorb gas I with reducing liquid to obtain pre-absorbed gas II, and then throttle the pre-absorbed gas II to obtain gas III, with a flow rate of gas III of 0.05-1m / s;

[0051] C: Gas III is deeply absorbed by the reduction liquid to obtain deeply absorbed gas IV. The deeply absorbed gas IV is separated by mist capture to obtain gas V and liquid I. Liquid I is reused as the reduction liquid.

[0052] According to the present invention, preferably, when the H2S concentration in gas V is less than 10 mg / m 3 When , gas V is directly discharged.

[0053] According to the present invention, preferably, when the H2S concentration in gas V is greater than 10 mg / m 3 The method further comprises step D: subjecting gas V to cyclone separation to obtain gas VI and liquid II, subjecting gas VI to collision to obtain gas VII and liquid III, subjecting gas VII to mist separation to obtain gas VIII and liquid IV, subjecting gas VIII to combustion in a burner (42) and then being discharged; and subjecting liquids II, III and IV to repeated use as reduction liquids.

[0054] According to the present invention, preferably, the reduction liquid in step A is the same as or different from that in step B, and the reduction liquid comprises an organic amine, an inorganic base and a promoter, and the weight ratio of the organic amine, the inorganic base and the promoter is 1:0.1-40:0.03-0.3, preferably 1:1-30:0.1-0.2, and more preferably 1:20-30:0.15-0.2, the organic amine comprises an alcohol amine and / or a polyamine, the inorganic base comprises an inorganic base containing an alkali metal and / or an alkaline earth metal, and the promoter comprises at least one of an imide, an amide, a nitrogen-containing six-membered heterocyclic compound, a nitrogen-containing condensed heterocyclic compound, a C2-C5 sulfoxide, a C3-C5 sulfone and a C2-C5 nitrile.

[0055] According to the present invention, preferably, the alcoholamine comprises ethanolamine and / or triethanolamine citrate.

[0056] According to the present invention, preferably, the polyamine comprises diethylenetriamine and / or triethylenetetramine.

[0057] According to the present invention, preferably, the organic amine is selected from a combination of one of triethanolamine citrate, diethylenetriamine and triethylenetetramine and ethanolamine; more preferably, the weight ratio of one of triethanolamine citrate, diethylenetriamine and triethylenetetramine to ethanolamine is 1:4-5.

[0058] According to the present invention, preferably, the inorganic base includes at least one of NaOH, Na2CO3, KOH, NaHCO3, K2CO3, Ca(OH)2 and Cs2CO3.

[0059] According to the present invention, preferably, the imide comprises N-hydroxyphthalimide.

[0060] According to the present invention, preferably, the amide includes at least one of N,N-dimethylacetamide, N,N-dimethylformamide and formamide.

[0061] According to the present invention, preferably, the nitrogen-containing six-membered heterocyclic compound includes pyridine.

[0062] According to the present invention, preferably, the nitrogen-containing fused heterocyclic compound comprises quinoline.

[0063] According to the present invention, preferably, the C2-C5 sulfoxide comprises dimethyl sulfoxide.

[0064] According to the present invention, preferably, the C3-C5 sulfone includes sulfolane.

[0065] According to the present invention, preferably, the C2-C5 nitrile comprises acetonitrile.

[0066] According to the present invention, preferably, the reduction fluid further comprises a defoamer and a solvent, the defoamer is an organosilicon defoamer, and the solvent comprises water or a C1-C5 alcohol.

[0067] According to the present invention, preferably, the weight ratio of the organic amine, the defoaming agent and the solvent is 1:0.003-0.1:0.1-30, preferably 1:0.03-0.08:1-25.

[0068] According to the present invention, preferably, the organosilicon defoamer includes at least one of a polydimethylsiloxane defoamer, a glycol siloxane defoamer and a polyether-modified organosilicon defoamer.

[0069] According to the present invention, preferably, the C1-C5 alcohol includes at least one of C1-C5 monohydric alcohol, C1-C5 dihydric alcohol and C1-C5 polyhydric alcohol, the C1-C5 monohydric alcohol includes at least one of ethanol, methanol and isopropanol, the C1-C5 dihydric alcohol includes ethylene glycol, and the C1-C5 polyhydric alcohol includes glycerol.

[0070] According to the present invention, preferably, the pH value of the reduction liquid is 7-11.

[0071] According to the present invention, preferably, in the gas containing H2S and CO2, the content of H2S is 0.00001-15% by volume, and the content of CO2 is 0-99% by volume, preferably the content of H2S is 0.1-15% by volume, and the content of CO2 is 5-20% by volume. Other gases in the gas containing H2S and CO2 may be nitrogen, methane, etc.

[0072] According to the present invention, preferably, the temperature of the gas containing H2S and CO2 is 20-80°C and the pressure is 0.1-8MPa.

[0073] According to the present invention, preferably, the amount of the reduction fluid is 1-30Nm 3 / h.

[0074] According to the present invention, preferably, the method is carried out in the following device, which comprises a gas source introduction mechanism 1, a pre-absorption tower 2, a deep absorption tower 3 and an optional deep separation tower 4 connected in sequence;

[0075] A throttling structure is provided between the gas source introduction mechanism 1 and the pre-absorption tower 2, and a throttling structure is provided between the pre-absorption tower 2 and the deep absorption tower 3;

[0076] The deep absorption tower 3 is provided with a gas distributor 3-1, a hollow reduction liquid sprayer 3-2, a liquid receiving pipe 3-3, a guide plate 3-5, a mist collector 3-6 and a gas discharge pipe 3-7 in sequence from bottom to top;

[0077] The deep absorption tower 3 is also provided with a first hollow tube 3-4, the bottom inlet of the first hollow tube 3-4 is located in the space between the hollow reduction liquid sprayer 3-2 and the gas uniform distributor 3-1, and the top outlet of the first hollow tube 3-4 is located in the space between the hollow reduction liquid sprayer 3-2 and the mist collector 3-6, so that the reacted gas can contact the mist collector 3-6 through the first hollow tube 3-4 to separate the reduction liquid;

[0078] One end of the guide plate 3-5 is connected to the top of the first hollow tube 3-4, and the other end is connected to the liquid receiving pipe 3-3, so that the reduction liquid separated by the mist collector 3-6 flows into the liquid receiving pipe 3-3 along the guide plate 3-5, and the liquid receiving pipe 3-3 is connected to the hollow reduction liquid sprayer 3-2 so that the separated reduction liquid flows back to the hollow reduction liquid sprayer 3-2.

[0079] According to the present invention, preferably, the hollow reducing liquid sprayer 3-2 is provided with a porous nozzle 3-21. The porous nozzle 3-21 is evenly distributed along the radial and axial directions of the hollow reducing liquid sprayer 3-2 so that the reducing liquid is evenly distributed in all directions in the deep absorption tower 3.

[0080] According to the present invention, preferably, the mist collector 3-6 has a porous structure, and the mist collector 3-6 can be a porous mesh structure composed of foam metal or non-metallic material.

[0081] According to the present invention, the number of deep absorption towers 3 in the device can be adjusted as needed. When there are multiple deep absorption towers 3, the deep absorption towers 3 can be connected in series or in parallel. Preferably, three deep absorption towers 3 are provided in the device and connected in parallel.

[0082] According to the present invention, preferably, the throttling structure between the gas source introduction mechanism 1 and the pre-absorption tower 2 includes a first large-diameter gas pipeline 7-1, a first small-diameter gas pipeline 8, and a first one-way pressure reducing valve 6 arranged on the first large-diameter gas pipeline 7, and the inner diameter ratio of the first large-diameter gas pipeline 7-1 to the first small-diameter gas pipeline 8-1 is 1.1-3: 1. The gas enters the pre-absorption tower 2 from the gas source introduction mechanism 1 through the large-diameter gas pipeline 7-1 and the small-diameter gas pipeline 8-1 in sequence.

[0083] According to the present invention, preferably, the throttling structure between the pre-absorption tower 2 and the deep absorption tower 3 includes a second large-diameter gas pipeline 7-2, a second small-diameter gas pipeline 8-2, and a second one-way pressure reducing valve 6-2 arranged on the second large-diameter gas pipeline 7-2, and the inner diameter ratio of the second large-diameter gas pipeline 7-2 to the second small-diameter gas pipeline 8-2 is 1.1-3: 1. The gas discharged from the pre-absorption tower 2 enters the deep absorption tower 3 through the second large-diameter gas pipeline 7-2 and the second small-diameter gas pipeline 8-2 in sequence, and first passes through the gas distributor 3-1 to make the gas flow evenly upward.

[0084] According to the present invention, preferably, a throttling structure can also be arranged between the deep absorption tower 3 and the deep separation tower 4, and the throttling structure between the deep absorption tower 3 and the deep separation tower 4 is composed of a gas discharge pipe 3-7 and a small-diameter gas pipeline, and the ratio of the gas discharge pipe 3-7 and the small-diameter gas pipeline is 1.1-3:1.

[0085] According to the present invention, preferably, a gas uniform distribution structure 2-1 and a reduction liquid spray pipe 2-2 are provided in the pre-absorption tower 2. In order to make the gas fully contact with the reduction liquid, more preferably, the reduction liquid spray pipe 2-2 is located above the gas uniform distribution structure 2-1. Further preferably, the radial and axial uniformly distributed pores of the reduction liquid spray pipe 2-2 are 0.1-0.15mm small holes, so that the reduction liquid is evenly sprayed out and contacts with the gas to reduce the content of H2S and CO2 in the gas.

[0086] According to the present invention, preferably, 2-6 reduction liquid spray pipes are arranged in the pre-absorption tower 2, and the angle between two adjacent reduction liquid spray pipes is 60-180 degrees. When two reduction liquid spray pipes are arranged in the pre-absorption tower 2, the angle between the two reduction liquid spray pipes is 180 degrees, and they are arranged in parallel with the gas uniform distribution structure 2-1. In order to further increase the contact probability between the gas and the reduction liquid, the number of reduction liquid spray pipes can be increased. It is further preferred that three reduction liquid spray pipes are arranged in the pre-absorption tower 2, and the angle between two adjacent reduction liquid spray pipes is 120 degrees. Figure 2 shown.

[0087] According to the present invention, preferably, the deep separation tower 4 is provided with a guide vane 4-1, a second hollow tube 4-2, a support plate 4-3, an inclined plate 4-4, a baffle 4-5 and a porous mist catcher 4-6. The gas discharged from the deep absorption tower 3 enters the deep separation tower 4 through the gas discharge pipe 3-7, so that the gas is subjected to cyclone separation under the action of the guide vane 4-1, and then passes through the second hollow tube 4-2, passes through the gap between the inclined plate 4-4 and the baffle 4-5, and then passes upward through the porous mist catcher 4-6 to be discharged from the deep separation tower 4.

[0088] The support plate 4-3 divides the deep separation tower 4 into an upper space and a lower space. The second hollow tube 4-2 is fixed at the center of the deep separation tower 4 perpendicular to the support plate 4-3. The bottom inlet and the top inlet of the second hollow tube 4-2 are respectively located in the lower space and the upper space. The guide vane 4-1 is located in the lower space and is connected to the inner wall of the deep separation tower 4 and the outer wall of the second hollow tube 4-2, so that part of the reduction liquid in the gas entering the lower space of the deep separation tower 4 is separated and enters the upper space of the deep separation tower 4 through the second hollow tube (4-2);

[0089] A porous mist-catching plate 4-6 is arranged in the upper space of the deep separation tower 4, a baffle 4-5 is fixed on the porous mist-catching plate 4-6, and an inclined plate 4-4 is arranged in parallel with the baffle 4-5, so that the gas entering the upper space from the second hollow tube 4-2 can only pass through the gap between the inclined plate 4-4 and the baffle 4-5 and then contact with the porous mist-catching plate 4-6 to further separate the reduction liquid.

[0090] According to the present invention, preferably, the vertical distance of the gap between the inclined plate 4-4 and the baffle 4-5 is 1-5 cm.

[0091] According to the present invention, preferably, the guide vane 4-1 has an inclination angle of 30-60 degrees with respect to the vertical direction. Under the action of the guide vane 4-1, the gas forms a downward rotating flow in the deep separation tower 4, and the droplets are thrown to the side wall and fall under the action of gravity, so as to achieve the purpose of gas-liquid separation. After separation, the liquid is collected at the bottom of the deep separation tower 4, and the separated gas enters the upper space through the hollow tube 4-2.

[0092] According to the present invention, preferably, the baffle 4-5 is a conical baffle. The center of the baffle 4-5 is fixed on the porous mist catching plate 4-6 and the edge extends toward the side wall of the deep separation tower 4, one end of the inclined plate 4-4 is fixed on the side wall of the deep separation tower 4 and the other end extends toward the porous mist catching plate 4-6, so that the inclined plate 4-4 is arranged opposite to the conical surface of the conical baffle.

[0093] According to the present invention, preferably, the device also includes a flame arrester 41, a burner 42 and an exhaust pipe 43 connected in sequence, and the flame arrester 41 is connected to the top of the deep separation tower 4 so that the separated gas enters the burner 42 for combustion and is discharged through the exhaust pipe 43.

[0094] According to the present invention, preferably, the device further comprises an H2S concentration measuring instrument 31 arranged on the gas discharge pipe 3-7, for measuring the H2S concentration in the exhaust gas of the gas discharge pipe 3-7;

[0095] The gas discharge pipe 3 - 7 is connected to the deep separation tower 4 and the exhaust pipe 43 through a pipeline, so that the gas that meets the discharge requirements is directly discharged through the exhaust pipe 43 , and the gas that does not meet the discharge requirements enters the deep separation tower 4 .

[0096] The gas discharged from the gas discharge pipe 3-7 is measured by the H2S concentration measuring instrument 31. When the H2S concentration in the gas is less than 10 mg / m 3 When the H2S concentration in the gas is greater than 10 mg / m 3 When the gas enters the deep separation tower 4, the gas obtained after the reduction liquid in the gas is deeply separated passes through the flame arrester 41 and is burned by the burner 42 and enters the exhaust pipe 43 for discharge.

[0097] According to the present invention, preferably, the device further comprises a reduction liquid storage tank 5 and an acid storage tank 51, an alkali storage tank 52 and a reduction liquid circulation pump 53 connected thereto, wherein the reduction liquid circulation pump 53 is connected to the pre-absorption tower 2 and the deep absorption tower 3 through a pipeline for providing the reduction liquid in the reduction liquid storage tank 5 to the reduction liquid spray pipe 2-2 and the hollow reduction liquid sprayer 3-2, and the reduction liquid storage tank 5 is connected to the bottom of the pre-absorption tower 2, the deep absorption tower 3 and the deep separation tower 4 through a pipeline so as to collect the reduction liquid recovered by the pre-absorption tower 2, the deep absorption tower 3 and the deep separation tower 4. The acid storage tank 51 is used to store acid, and the alkali storage tank 52 is used to store alkali, and the acid and alkali are used to adjust the pH value of the reduction liquid in the reduction liquid storage tank 5. The acid is a hydrochloric acid solution and / or an acetic acid solution. The alkali is at least one of a sodium hydroxide solution, a potassium hydroxide solution, a cesium carbonate solution, an ethanolamine solution and a formamide solution. The acid solution is an acid aqueous solution and / or an acid alcohol solution, and the alkali solution is an alkali aqueous solution and / or an alkali alcohol solution.

[0098] According to the present invention, preferably, a pH meter 5-2 and a stirrer 5-1 are provided in the reduction liquid storage tank 5. The pH meter 5-2 is used to detect the pH value of the reduction liquid in the reduction liquid storage tank 5, and then the pH value of the reduction liquid in the reduction liquid storage tank 5 is adjusted to 7-11 using acid and alkali. The stirrer 5-1 is used to make the components of the reduction liquid in the reduction liquid storage tank 5 evenly distributed.

[0099] According to the present invention, the device can also connect the gas discharge pipe 3-7 to the inlet of the deep absorption tower 3 by adding a pipeline, so that the gas circulates in the deep absorption tower 3 to reduce the concentration of H2S until the concentration of H2S is lower than the emission standard, and then directly discharged or enters the deep separation tower 4. According to the requirements of Table 3 in GB31573-2015 (Inorganic Chemical Industry Pollutant Emission Standard), the limit value of H2S emission in the atmosphere is 10 mg / m 3 .

[0100] In the present invention, the pipelines and equipment in the device are all made of materials resistant to H2S and CO2 corrosion.

[0101] When conducting simulation experiments in the laboratory, gases containing H2S and CO2 will also be produced, which may be tail gas during the experiment or gas accidentally leaked during the experiment. Therefore, the device of the present invention is also suitable for treating gases containing H2S and CO2 produced during the experimental simulation process. When used for experimental simulation experiments, the experimental simulation device can be used as a gas source introduction mechanism 1, and an isolation room 9 needs to be added to the periphery of the gas source introduction mechanism 1, and a large-caliber gas pipeline 7 passes through the middle of the top of the isolation room 9. It is also necessary to punch a hole at the top of the next-door room 9 to allow the first air inlet pipe 9-1 to pass through, and install a first one-way valve 9-2 and a first air pump 9-3 on the first air inlet pipe 9-1, and punch a hole at the bottom of the next-door room 9 to allow the second air inlet pipe 9-1-1 to pass through, and install a second one-way valve 9-2-1 and a second air pump 9-3-1 on the second air inlet pipe 9-1-1. When gas is produced, the gas can directly enter the device of the present invention through the large-caliber gas pipeline 7. When gas leakage occurs, the first air inlet pipe 9-1, the first non-return valve 9-2 and the first air pump 9-3 can be opened to allow external gas to enter the isolation room 9 through the first air inlet pipe 9-1 to dilute the gas in the isolation room 9, and the second air inlet pipe 9-1-1, the second non-return valve 9-2-1 and the second air pump 9-3-1 can be opened to allow the gas in the isolation room 9 to enter the device of the present invention through the second air inlet pipe 9-1-1. After entering the device of the present invention, H2S and CO2 can be removed according to the method of the present invention.

[0102] The following reference Figure 1 and Figure 2 The schematic diagram of the process flow of treating gas containing H2S and CO2 of the present invention is shown, and the working process of the device for treating gas containing H2S and CO2 is described.

[0103] The gas containing H2S and CO2 is introduced into the gas source introduction mechanism 1 and sequentially passes through the first large-caliber gas pipeline 7-1, the first one-way pressure reducing valve 6-1 and the first small-caliber gas pipeline 8-1 to reduce the temperature and pressure of the gas containing H2S and CO2 to obtain gas I. Gas I enters the pre-absorption tower 2, and firstly passes through the horizontally arranged gas uniform distribution structure 2-1 to make the gas uniformly dispersed and flow upward, and then contacts with the reduction liquid sprayed by the reduction liquid spray pipe 2-2 to absorb H2S and CO2, and obtains the pre-absorbed gas II. Gas II then passes through the second large-caliber gas pipeline 7-2, the second one-way pressure reducing valve 6-2 and the second small-caliber gas pipeline 8-2 to further reduce the temperature and pressure of the gas containing H2S and CO2 to obtain gas III. Gas III enters the deep absorption tower 3, and firstly passes through the horizontally arranged gas uniform distributor 3-1 to make the gas uniformly dispersed and flow upward, and then contacts with the reduction liquid sprayed by the porous nozzle 3-21 to absorb H2S and CO2, and obtains the deeply absorbed gas IV. After passing through the first hollow tube 3-4, gas IV contacts the mist collector 3-6 to separate liquid I from gas IV to obtain gas V. Liquid I retained by the mist collector 3-6 drips onto the guide plate 3-5, and then collects into the liquid receiving pipe 3-3 and recirculates back to the hollow reduction liquid sprayer 3-2 for reuse as reduction liquid. Gas V is discharged from the deep absorption tower 3 through the gas discharge pipe 3-7, and then the H2S concentration in gas V is measured by the H2S concentration measuring instrument 31. When the H2S concentration in gas V is less than 10mg / m 3 When the H2S concentration in gas V is greater than 10 mg / m 3When the gas V enters the deep separation tower 4, the centrifugal force of cyclone separation is generated under the action of the guide blade 4-1, so that the gas and liquid in the gas V are separated to obtain gas VI and liquid II. The gas VI enters the upper space of the deep separation tower 4 through the second hollow tube 4-2, and then collides with the inclined plate 4-4 and the baffle 4-5 to obtain gas VII and liquid III. The gas VII passes through the gap between the inclined plate 4-4 and the baffle 4-5 and goes up to the porous mist catching plate 4-6. Under the action of the porous mist catching plate 4-6, the gas VIII is separated to obtain gas VIII and liquid IV. The gas VIII passes through the flame arrester 41 and is burned by the burner 42 and enters the exhaust pipe 43 for discharge. Liquid II, liquid III and liquid IV are refluxed to the reduction liquid storage tank 5 through the pipeline and reused. The reduction liquid storage tank 5 is filled with reduction liquid, which is an alkaline liquid with a controlled pH value of 7-11. The reduction liquid storage tank 5 is provided with a pH meter 5-2, and is connected with the acid storage tank 51 and the alkali storage tank 52. The pH meter 5-2 monitors the pH value of the reduction liquid in real time, and adds acid or alkali into the reduction liquid storage tank 5 through an automatic adjustment device to adjust the pH value of the reduction liquid. The reduction liquid storage tank 5 is also provided with an agitator 5-1 to ensure that the components in the reduction liquid in the reduction liquid storage tank 5 are evenly dispersed. The reduction liquid storage tank 5 provides reduction liquid to the reduction liquid spray pipe 2-2 and the hollow reduction liquid sprayer 3-2 through the reduction liquid circulation pump 53. The reduction liquid storage tank 5 is connected to the bottom of the pre-absorption tower 2, the deep absorption tower 3 and the deep separation tower 4 through a pipeline for recovering the reduction liquid.

[0104] The present invention will be described in detail below by way of examples, but the present invention is not limited to the following examples.

[0105] Example 1

[0106] Use as Figure 1 and Figure 2 The device shown processes a gas containing H2S and CO2, wherein the temperature of the gas containing H2S and CO2 is 80°C, the pressure is 4MPa, and the flow rate is 0.26m / s, and comprises the following steps:

[0107] Add the reducing liquid into the reducing liquid storage tank 5, start the agitator 5-1 to make the reducing liquid evenly dispersed, monitor the pH value of the reducing liquid in real time with the pH meter 5-2, and control the pH value of the reducing liquid by adding acid or alkali through the acid storage tank 51 or the alkali storage tank 52, and then provide the reducing liquid to the reducing liquid spray pipe 2-2 and the hollow reducing liquid sprayer 3-2 through the reducing liquid circulation pump 53. The composition and pH value of the reducing liquid are shown in Table 1. The amount of reducing liquid is 25Nm 3 / h.

[0108] A: The H2S and CO2-containing gas to be treated in the gas source introduction mechanism 1 passes through the first large-diameter gas pipeline 7-1, the first one-way pressure reducing valve 6-1 and the first small-diameter gas pipeline 8-1 (the inner diameter ratio of the first large-diameter gas pipeline 7-1 to the first small-diameter gas pipeline 8-1 is 2:1) in sequence to reduce the temperature and pressure of the H2S and CO2-containing gas to obtain gas I. The H2S and CO2 contents in the H2S and CO2-containing gas to be treated are shown in Table 2.

[0109] B: Gas I is sent to the pre-absorption tower 2 for pre-absorption with the reducing liquid, and the flow rate of gas I is 1.05m / s. Gas I first passes through the horizontally arranged gas uniform distribution structure 2-1 to make the gas evenly dispersed and flow upward, and then contacts with the reducing liquid sprayed by the reducing liquid spray pipe 2-2 to absorb H2S and CO2 to obtain the pre-absorbed gas II. The pre-absorbed gas II then passes through the second large-diameter gas pipeline 7-2, the second one-way pressure reducing valve 6-2 and the second small-diameter gas pipeline 8-2 (the inner diameter of the second large-diameter gas pipeline 7-2 and the second small-diameter gas pipeline 8-2 is 3:1) to reduce the temperature and pressure of the gas containing H2S and CO2 to obtain gas III.

[0110] C: Gas III is sent into the deep absorption tower 3 for deep absorption, and the flow rate of gas III is 0.5m / s. Gas III first passes through the horizontally arranged gas distributor 3-1 to make the gas evenly dispersed and flow upward, and then contacts with the reduction liquid sprayed by the porous nozzle 3-21 to absorb H2S and CO2 to obtain gas IV after deep absorption. After passing through the first hollow tube 3-4, gas IV contacts with the mist collector 3-6 to separate the liquid I in gas IV to obtain gas V. Liquid I drips on the guide plate 3-5, and then collects in the liquid receiving pipe 3-3 and recirculates back to the hollow reduction liquid sprayer 3-2 for reuse as reduction liquid. The concentration of H2S in gas V measured by the H2S concentration measuring instrument 31 is 5mg / m 3 , reaching the emission standards, and can be discharged through the exhaust pipe 43.

[0111] Example 1-1

[0112] The gas containing H2S and CO2 was treated according to the method of Example 1, except that the amount of the reduction liquid was 30 Nm 3 / h, the contents of H2S and CO2 in the gas containing H2S and CO2 to be treated are shown in Table 2. The concentration of H2S in gas V is shown in Table 2.

[0113] Example 2-11

[0114] The gas containing H2S and CO2 is treated according to the method of Example 1, except that the composition of the reduction liquid and the content of H2S and CO2 in the gas containing H2S and CO2 to be treated are different. The composition of the reduction liquid is shown in Table 1, and the content of H2S and CO2 in the gas containing H2S and CO2 to be treated is shown in Table 2.

[0115] When the H2S concentration in the gas V measured by the H2S concentration measuring instrument 31 is lower than 10 mg / m 3 When the gas reaches the emission standard, it can be discharged through the exhaust pipe 43. The concentration of H2S in the gas V is shown in Table 2.

[0116] When the H2S concentration in the gas V measured by the H2S concentration measuring instrument 31 is higher than 10 mg / m 3 When the gas V is sent to the deep separation tower 4 for deep separation, the gas V is cyclone-separated under the action of the guide blade 4-1 after entering the deep separation tower 4 to obtain gas VI and liquid II, the gas VI collides with the inclined plate 4-4 and the baffle 4-5 to obtain gas VII and liquid III, the gas VII is separated by mist capture to obtain gas VIII and liquid IV, the gas VIII passes through the flame arrester 41 and the burner 42 to be burned and enter the exhaust pipe 43 for discharge; the liquids II, III and IV flow back to the reduction liquid storage tank 5 through the bottom of the deep separation tower 4 and are reused as reduction liquid.

[0117] Example 12

[0118] The gas containing H2S and CO2 is treated according to the method of Example 1, except that the first large-diameter gas pipeline 7-1, the first small-diameter gas pipeline 8-1, the second large-diameter gas pipeline 7-2 and the second small-diameter gas pipeline 8-2 are replaced by pipes with the same inner diameter, and the first one-way pressure reducing valve 6-1 and the second one-way pressure reducing valve 6-2 are replaced by ordinary one-way valves.

[0119] Table 1

[0120]

[0121]

[0122] Table 2

[0123]

[0124] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for treating a gas containing H2S and CO2, characterized in that: The method comprises the following steps: A: The gas containing H2S and CO2 to be treated is throttled through the throttling structure between the gas source introduction mechanism and the pre-absorption tower to obtain gas I, and the flow rate of gas I is 0.1-1.5m / s; The throttling structure between the gas source introduction mechanism and the pre-absorption tower includes a first large-diameter gas pipeline, a first small-diameter gas pipeline and a first one-way pressure reducing valve arranged on the first large-diameter gas pipeline; B: pre-absorb gas I with a reducing liquid to obtain pre-absorbed gas II, and throttle the pre-absorbed gas II through a throttling structure between the pre-absorption tower and the deep absorption tower to obtain gas III, and the flow rate of gas III is 0.05-1m / s; the throttling structure between the pre-absorption tower and the deep absorption tower includes a second large-diameter gas pipeline, a second small-diameter gas pipeline, and a second one-way pressure reducing valve arranged on the second large-diameter gas pipeline; C: Gas III is deeply absorbed by the reduction liquid to obtain deeply absorbed gas IV. The deeply absorbed gas IV is separated by mist capture to obtain gas V and liquid I. Liquid I is reused as the reduction liquid; D: When the H2S concentration in gas V is less than 10 mg / m 3 When the H2S concentration in gas V is greater than 10 mg / m 3 When the gas V is subjected to cyclone separation, the gas VI and liquid II are obtained; Wherein, the deep absorption is carried out in a deep absorption tower, which includes a gas uniform distributor, a hollow reduction liquid sprayer, a liquid receiving pipe, a guide plate, a mist collector, a gas discharge pipe and a first hollow pipe; The bottom inlet of the first hollow tube is located between the hollow reducing liquid sprayer and the gas uniform distributor, and the top outlet of the first hollow tube is located between the hollow reducing liquid sprayer and the mist catcher; one end of the guide plate is connected to the top of the first hollow tube, and the other end is connected to the liquid receiving pipe; the liquid receiving pipe is connected to the hollow reducing liquid sprayer; The cyclone separation is carried out in a deep separation tower, which includes a guide vane, a second hollow tube, a support plate, an inclined plate, a baffle and a porous mist catcher. The gas V enters the deep separation tower and is cyclone separated under the action of the guide vane, passes through the second hollow tube, passes through the gap between the inclined plate and the baffle, and then is discharged from the deep separation tower through the porous mist catcher. Wherein, the reduction liquid in step B is the same as or different from that in step C, and the reduction liquid comprises an organic amine, an inorganic base and a promoter, and the weight ratio of the organic amine, the inorganic base and the promoter is 1:0.1-40:0.03-0.3; the organic amine comprises ethanolamine, triethanolamine citrate, diethylenetriamine or triethylenetetramine; the inorganic base comprises at least one of NaOH, Na2CO3, KOH, NaHCO3, K2CO3, Ca(OH)2 and Cs2CO3; the promoter comprises at least one of N-hydroxyphthalimide, N,N-dimethylacetamide, N,N-dimethylformamide, formamide, pyridine, quinoline, dimethyl sulfoxide, sulfolane and acetonitrile.

2. The method according to claim 1, wherein: The reduction liquid also includes a defoamer and a solvent, and the weight ratio of the organic amine, the defoamer and the solvent is 1:0.003-0.1:0.1-30.

3. The method according to claim 2, wherein: The defoaming agent is an organosilicon defoaming agent, and the solvent includes water or C1-C5 alcohol.

4. The method according to claim 3, wherein: The organosilicon defoamer includes at least one of a polydimethylsiloxane defoamer, a glycol siloxane defoamer and a polyether-modified organosilicon defoamer.

5. The method according to claim 3, wherein: The C1-C5 alcohol includes at least one of a C1-C5 monohydric alcohol, a C1-C5 dihydric alcohol and a C1-C5 polyhydric alcohol.

6. The method according to claim 5, wherein: The C1-C5 monohydric alcohol includes at least one of ethanol, methanol and isopropanol; And / or, the C1-C5 diol includes ethylene glycol; And / or, the C1-C5 polyol includes glycerol.

7. The method according to claim 1, wherein: The pH value of the reduction liquid is 7-11.

8. The method according to claim 1, wherein: In the gas containing H2S and CO2, the content of H2S is 0.00001-15% by volume, and the content of CO2 is 0-99% by volume.

9. The method according to claim 1, wherein: In the gas containing H2S and CO2, the content of H2S is 0.1-15% by volume, and the content of CO2 is 5-20% by volume.

10. The method according to any one of claims 1 to 9, wherein: The temperature of the gas containing H2S and CO2 is 20-80°C and the pressure is 0.1-8MPa.

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