Novel natural gas desulfurization device and method

Abstract

The invention provides a novel natural gas desulfurization device and method, and belongs to the technical field of natural gas extraction. The device comprises a desulfurization unit and a reaction unit, the desulfurization unit adopts water as a desulfurization medium and is in countercurrent contact with to-be-desulfurized natural gas, acid gas in the to-be-desulfurized natural gas is dissolved, acid-rich gas absorption liquid and desulfurized natural gas are generated, and the reaction unit receives the acid-rich gas absorption liquid and is subjected to a neutralization reaction with an alkaline solid reactant to generate desulfurized natural gas. Solid by-products, purified liquid and by-product gas are generated. Water is used for replacing a traditional alcohol amine solution, the toxicity and corrosion problems are avoided, the service life of equipment is prolonged, meanwhile, full recovery and cyclic utilization of desulfurization products are achieved, and the method is suitable for various natural gas exploitation scenes and especially suitable for ocean platforms with high environmental protection requirements.

Description

Technical Field

[0001] The present application relates to the field of natural gas extraction, and in particular to a novel natural gas desulfurization device and method, which is suitable for processing output during oil and gas well extraction. Background Art

[0002] In the technical field of obtaining natural gas from wells, after natural gas is extracted from an oil well (such as a land oil well or the wellhead of an offshore oil and gas drilling platform), the composition of the wellhead output is complex. In addition to the target natural gas, it also carries a certain amount of water vapor and a considerable amount of and Acid gases such as chlorinated hydrocarbons are key harmful components in well output that need to be separated and removed. In onshore oil and gas production, these acid gases can reduce pipeline transportation capacity, increase pressure drop in gas gathering lines, and aggravate equipment corrosion. In severe cases, they can cause pipeline blockages, leading to forced production interruptions. In special scenarios such as offshore oil and gas production platforms, due to the limited space and compact equipment layout of offshore platforms, the corrosive effects of acid gases can cause more rapid damage to the densely packed pipelines and equipment on the platforms, increasing maintenance costs and safety hazards. At the same time, the marine environment has extremely high environmental protection requirements. The leakage or improper handling of acid gases will not only pollute the marine ecology, but may also cause serious safety accidents.

[0003] Existing methods for treating acidic gases in well outputs typically involve dissolving and removing them with alcoholamine solutions. However, alcoholamine solutions are toxic and corrosive, which can reduce the lifespan of equipment and increase replacement frequency in onshore production. On offshore oil and gas platforms, their corrosive nature further shortens the lifespan of equipment, which is already difficult to maintain due to space constraints. Furthermore, the storage, transportation, and leakage risks of these toxic substances pose additional threats to the marine environment, making them incompatible with the high safety and environmental standards of marine production.

[0004] Therefore, there is an urgent need for a natural gas desulfurization device and method that is suitable for various natural gas extraction scenarios, is more environmentally friendly and can extend the service life of the equipment, so as to solve the many problems existing in the existing amine solution treatment method. Summary of the Invention

[0005] The purpose of the present application is to provide a new natural gas desulfurization device and method, which uses water instead of alcohol amine solution for desulfurization treatment, so as to solve the problems of environmental pollution and reduced equipment service life in the prior art of using alcohol amine solution for natural gas desulfurization.

[0006] The embodiments of the present application can be implemented through the following technical solutions: A new natural gas desulfurization device, comprising: A desulfurization unit is used to bring the desulfurization medium into countercurrent contact with the natural gas to be desulfurized to dissolve the acid gas, and output the desulfurized natural gas and the acid gas-rich absorption liquid respectively; A reaction unit is used to receive the acidic gas absorption liquid and neutralize it with the alkaline solid reactant to generate a mixed slurry containing solid by-products, and output the solid precipitate, purified liquid and reaction by-product gas respectively; Wherein, the desulfurization medium is water, and the first liquid outlet of the desulfurization unit is connected to the second liquid inlet of the reaction unit.

[0007] Furthermore, the desulfurization unit includes a first gas outlet arranged on the top, and a first liquid inlet, a first gas inlet and a first liquid outlet arranged on the side wall in order from top to bottom; The height of the first air inlet is lower than the liquid level in the desulfurization unit.

[0008] Furthermore, a metal ball packing layer is provided inside the desulfurization unit. The metal ball packing layer is composed of a plurality of arranged metal balls and is located between the first liquid inlet and the first gas inlet.

[0009] Furthermore, the number of the metal ball filler layers is at least one, and two adjacent metal ball filler layers are spaced apart in the vertical direction; And / or, the metal ball is a hollow sphere; And / or, the metal ball is made of stainless steel.

[0010] Furthermore, a condenser is provided at the top of the desulfurization unit to remove water entrained in the desulfurized natural gas; And / or, the desulfurization unit is further provided with a first liquid level monitoring component for monitoring the liquid level to ensure that the liquid level in the desulfurization unit is always higher than the first air inlet.

[0011] Furthermore, the reaction unit includes a reactant inlet and a second gas outlet provided on the top, and a second liquid inlet and a second liquid outlet provided on the side wall, and a sediment collection mechanism is provided at the bottom of the reaction unit for collecting and discharging solid sediment; And / or, the number of the reaction unit is at least one, and when the number is greater than one, the reaction units are arranged in series.

[0012] Furthermore, the desulfurization device further comprises a liquid distribution unit connected in series with the reaction unit, the liquid distribution unit comprising a third liquid inlet and a third liquid outlet, the third liquid inlet being communicated with the second liquid outlet of the reaction unit for receiving the purified liquid; the third liquid outlet being connected with the first liquid inlet and / or the discharge system of the desulfurization unit to realize recycling or discharge of the purified liquid; A second liquid level monitoring component is provided in the liquid distribution unit for monitoring the liquid level of the purified liquid and controlling the flow of the pipeline corresponding to the third liquid outlet according to the liquid level signal.

[0013] A natural gas desulfurization method comprises the following steps: S1, bringing the natural gas to be desulfurized into countercurrent contact with the desulfurization medium to dissolve the acid gas in the natural gas to generate an acid gas-rich absorption liquid, and simultaneously obtain desulfurized natural gas; S2, mixing the acid gas-rich absorption liquid with the alkaline solid reactant to perform a neutralization reaction to generate a mixed slurry containing solid by-products and reaction by-product gas; S3, separating the solid precipitate in the mixed slurry for recovery, recycling the purified liquid to step S1 or discharging it, and transporting the reaction by-product gas to the dehydration stage; Wherein, the desulfurization medium is water.

[0014] Furthermore, the volume flow ratio of the water to the natural gas to be desulfurized is 1:1 to 1:10; And / or, the alkaline solid reactant is limestone, and the mass flow ratio of the alkaline solid reactant to the natural gas to be desulfurized is greater than 1:10.

[0015] Furthermore, the S1 also involves pre-dehydration treatment of natural gas, and the pre-dehydration treatment includes: A metal ball packing layer is set in the countercurrent contact area, and the water vapor carried in the natural gas is removed by condensation through contact between the natural gas and the metal balls. The condensed water falls and is discharged with the acid gas-rich absorption liquid; And / or, a condenser is provided at the top of the countercurrent contact area to further remove water entrained in the desulfurized natural gas.

[0016] The embodiments of the present application provide a novel natural gas desulfurization device and method having at least the following beneficial effects: This application uses water to replace the traditional alcohol amine solution as the desulfurization medium, avoiding the toxicity and corrosiveness of alcohol amine from the source, avoiding the environmental pollution problems caused by it, and at the same time reducing equipment corrosion loss and extending the service life of the equipment. Water efficiently captures the sulfur in natural gas through dissolution. 、 , forming an acid gas-rich absorption liquid, which is then mixed with limestone ( ) undergoes a neutralization reaction, converting the soluble acidic substances into The reaction products include desulfurized natural gas, which can be used directly after treatment, solid precipitates, and other insoluble solids, achieving solidification and separation of acidic gases. The desulfurized natural gas can be used directly after treatment, the solid precipitates can be recycled as industrial raw materials, and the purified liquid can be recycled back to the desulfurization process, achieving efficient recycling of resources throughout the entire process.

[0017] This application completes the above-mentioned natural gas desulfurization process through the collaborative device setting of "desulfurization unit-reaction unit-liquid distribution unit", and improves the processing efficiency through further targeted structural improvements, such as setting a metal ball packing layer in the reaction unit, which is driven by natural gas to move in situ to form turbulence, thereby increasing the gas-liquid contact area and time, and improving the 、 The dissolution efficiency is improved, and the condensation nuclei of the metal balls are used to absorb water vapor. The attached water is washed into the bottom liquid pool by the inflowing water, which not only strengthens the dissolution of acidic gas but also pre-removes some water vapor. By setting up a condenser, the rising desulfurized natural gas is pre-treated and dehydrated, reducing the load of the subsequent dehydration process. The liquid level control design ensures that the natural gas inlet is always immersed in water to ensure the adequacy of the reaction and the safety of the system. The reaction unit adopts a conical bottom structure, combined with a screw conveyor and a solenoid valve, so that The solid precipitates gather along the cone wall and are efficiently discharged and recovered, avoiding accumulation that affects the reaction efficiency and achieving efficient solid-liquid separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of a natural gas desulfurization device provided in an embodiment of the present application; Numbers in the figure 1-desulfurization unit, 11-first gas outlet, 12-first liquid inlet, 13-first gas inlet, 14-first liquid outlet, 15-metal ball packing layer, 16-condenser, 17-first liquid level monitoring assembly, 2-reaction unit, 21-reactant inlet, 22-second liquid inlet, 23-second gas outlet, 24-second liquid outlet, 25-pressure control valve, 26-check valve, 27-screw conveyor, 28-solenoid valve, 29-collection box, 3-liquid distribution unit, 31-third liquid inlet, 32-third liquid outlet, 33-second liquid level monitoring assembly; DETAILED DESCRIPTION Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

[0019] In addition, various components in the drawings are enlarged or reduced in size for ease of understanding, but this is not intended to limit the scope of protection of this application.

[0020] Words importing the singular include the plural and vice versa.

[0021] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or are the orientation or positional relationship in which the products of the embodiments of the present application are usually placed when in use, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, in order to distinguish different units, words such as first and second are used in this specification, but these are not limited by the order of manufacture, nor can they be understood as indicating or implying relative importance. Their names may be different in the detailed description and claims of the present application.

[0022] The vocabulary in this specification is used to illustrate the embodiments of the present application, but is not intended to limit the present application. It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or a communication between the two components. For those skilled in the art, the specific meanings of the above terms in this application can be specifically understood.

[0023] On the one hand, this application provides a new type of natural gas desulfurization device, which aims to solve the problems of environmental pollution and shortened equipment life caused by alcohol amine solution desulfurization in the existing technology. The core solution is to use water as the desulfurization medium and achieve efficient desulfurization and environmental protection through the coordinated design of desulfurization unit + reaction unit. Figure 1 As shown, the natural gas desulfurization device provided in the embodiment of the present application includes a desulfurization unit 1 and a reaction unit 2. The desulfurization unit 1 is used to make the desulfurization medium contact with the natural gas to be desulfurized in countercurrent to dissolve the acid gas, and output the desulfurized natural gas and the acid gas-rich absorption liquid respectively; the reaction unit 2 is used to receive the acid gas-rich absorption liquid and make it react with the alkaline solid reactant to neutralize it to generate a mixed slurry containing solid by-products, and output the solid precipitate, purified liquid and reaction by-product gas respectively.

[0024] Furthermore, the desulfurization medium is water, and the acid gas refers to the 、 The alkaline solid reactant may be selected from limestone ( )、Carbide slag( ) and other energy The substance that reacts to form a precipitate of insoluble metal sulfide, preferably, the alkaline solid reactant is limestone.

[0025] In order to better understand this application, the reaction mechanism is first described: In the desulfurization unit 1, water is used as the desulfurization medium to countercurrently contact the natural gas to be desulfurized, and the acid gas in the natural gas (mainly and ) is dissolved in water, and the main reactions are as follows: (1) ; , and form carbonic acid: ; That is, in the desulfurization unit 1, the acid gas in the natural gas to be desulfurized ( and ) transfers from the gas phase to the liquid phase and dissolves in water to form a rich acid gas absorption liquid, while the methane in the natural gas ( ) and other components hardly participate in the dissolution process and are discharged as desulfurized natural gas after gas-liquid separation; In the reaction unit 2, the acid gas absorbing liquid and the alkaline solid reactant undergo a neutralization reaction, preferably limestone ( ) as an example, the main reactions are as follows: (1) Limestone and reaction: ; (2) The dissolved carbonic acid reaction: , generated further reaction with limestone; (3) Side reactions of calcium sulfide hydrolysis: , this reaction can be inhibited when limestone is sufficient; (4) Methane precipitation: , due to the limestone and The reaction is an exothermic reaction, which causes the temperature of the liquid in the reaction unit 2 to rise, causing part of the methane dissolved in the liquid to precipitate.

[0026] That is, in the reaction unit 2, the acidic components in the acid-rich gas absorption liquid are neutralized by the above reaction ( and recycled in the reaction chain) to obtain purified liquid, while generating insoluble solid by-products ( 、 etc.) and by-product gases (mainly precipitated methane).

[0027] Specifically, the top of the shell of the desulfurization unit 1 is provided with a first gas outlet 11 for discharging the desulfurized natural gas, and the side wall is provided with a first liquid inlet 12, a first gas inlet 13 and a first liquid outlet 14 in sequence from top to bottom; wherein the first liquid inlet 12 is used to introduce water as a desulfurization medium, the first gas inlet 13 is used to pass the natural gas to be desulfurized, and the first liquid outlet 14 is used to discharge the dissolved 、 By arranging the first liquid inlet 12 above the first gas inlet 13, a countercurrent flow path is formed, with water flowing from top to bottom and the natural gas to be desulfurized flowing from bottom to top. That is, a countercurrent contact zone between the water and the natural gas to be desulfurized is formed between the first liquid inlet 12 and the first gas inlet 13. This design allows the water and the natural gas to have a longer gas-liquid contact time in this countercurrent contact zone, thereby improving the solubility rate of the acid gas.

[0028] In some preferred embodiments, the height of the first air inlet 13 is set to be lower than the liquid level in the desulfurization unit 1. By setting the height of the first air inlet 13 lower than the liquid level, it is ensured that the natural gas to be desulfurized always directly contacts with water first after it is introduced to preliminarily dissolve the acidic gas therein, thereby avoiding the problem of the acidic gas being discharged without contact.

[0029] In some preferred embodiments, the first liquid inlet 12 and the first gas inlet 13 are arranged on the same side, and the first liquid outlet 14 and the first gas inlet 13 are arranged on both sides radially opposite to each other. This arrangement allows water and the natural gas to be desulfurized to form a more sufficient convection circulation in the desulfurization unit 1, increases the probability and area of ​​gas-liquid contact, and allows the acid gas to be more fully dissolved in the water.

[0030] In some preferred embodiments, a metal ball packing layer 15 is further provided in the countercurrent contact zone (i.e., between the first liquid inlet 12 and the first gas inlet 13), which is composed of a plurality of arranged metal balls. When the rising natural gas flows through the metal ball packing layer 15, the metal balls rotate or slightly displace in place because their own gravity is greater than the buoyancy of the gas. On the one hand, this can disrupt the flow path of the natural gas to form turbulence, prolong the gas-liquid contact time, and significantly improve the dissolution rate of the acid gas. On the other hand, the metal balls also act as condensation nuclei to promote the condensation of water vapor in the natural gas, forming droplets attached to the surface of the spheres, which can pre-remove the water vapor carried in the natural gas. When water is injected from the first liquid inlet 12 and flows through the metal ball packing layer 15, the water flow brings the condensed water attached to the surface of the spheres and the dissolved acid gas into the bottom liquid pool. Preferably, The metal ball is a hollow sphere; more preferably, the number of the metal ball packing layer 15 is at least one layer, that is, the number of the metal ball packing layer 15 can be 1 layer, 2 layers or more layers, and the upper and lower adjacent layers are spaced apart in the vertical direction to further improve the processing efficiency; specifically, the metal ball can be a sphere made of metal materials such as stainless steel, copper alloy, nickel alloy, etc. These metal materials have sufficient structural strength and density, which can not only meet the needs of in-situ rotation or micro-displacement under the action of airflow, but also promote water vapor condensation by relying on the thermal conductivity of the metal surface; preferably, the metal ball is made of stainless steel material. The surface of the stainless steel sphere is smooth and corrosion-resistant, which can not only extend the service life, but also its smooth surface can promote moisture to spread on the surface of the sphere to form a liquid film, further increasing the gas-liquid contact area.

[0031] In some preferred embodiments, a condenser 16 is further provided at the top of the desulfurization unit 1, which is arranged between the first liquid inlet 12 and the first gas outlet 11. It can adopt a conventional structure in the field and is not specifically limited here. It is used to further remove entrained water in the desulfurized natural gas.

[0032] In some preferred embodiments, the desulfurization unit 1 is further provided with a first liquid level monitoring component 17 for real-time monitoring of the internal liquid level. The monitoring signal can be transmitted to a control system, which then adjusts the flow rate of the first liquid outlet 14 to ensure that the liquid level within the desulfurization unit 1 is always higher than the first air inlet 13. In some specific embodiments, the first liquid level monitoring component 17 includes a first upper liquid level gauge and a first lower liquid level gauge. When the liquid level reaches the first upper liquid level gauge, the first liquid level monitoring component 17 feeds back a signal to the control system, which then controls the drainage rate of the first liquid outlet 14 (for example, by controlling a water pump in a pipeline connecting the first liquid outlet 14). When the liquid level drops to the first lower liquid level gauge, the first liquid level monitoring component 17 again feeds back a signal, which in turn controls the drainage rate of the first liquid outlet 14 to slow down. Through this dynamic adjustment method, the liquid level within the desulfurization unit 1 is always stabilized at a level higher than the first air inlet 13, while preventing water backflow caused by excessively high liquid levels, thereby ensuring effective gas-liquid contact and safe system operation.

[0033] Specifically, the reaction unit 2 includes a reactant inlet 21 and a second gas outlet 23 arranged at the top, a second liquid inlet 22 and a second liquid outlet 24 arranged on the side wall, and a precipitation collection mechanism arranged at the bottom; the reactant inlet 21 is used to add alkaline solid reactants into the reaction unit 2, and the second gas outlet 23 is used to discharge the reaction by-product gas, which can be connected to the subsequent dehydration link through a pipeline; the second liquid inlet 22 is connected to the first liquid outlet 14 of the desulfurization unit 1, for receiving the acidic gas absorption liquid from the desulfurization unit 1; the second liquid outlet 24 is used to discharge the purified liquid after the reaction.

[0034] In some preferred embodiments, the bottom of the reaction unit 2 is a conical structure, and the conical structure cooperates with a sedimentation collection mechanism disposed at the bottom to achieve efficient solid-liquid separation.

[0035] In some specific embodiments, the precipitation collection mechanism includes a screw conveyor 27 and a collection box 29. The screw conveyor 27 is arranged at the bottom of the reaction unit 2, and its discharge port is connected to the collection box 29 arranged outside the reaction unit 2 through a pipeline. The solid by-products generated by the reaction in the reaction unit 2 are settled and accumulated at the bottom, and then transported to the collection box 29 through the screw conveyor 27; preferably, the precipitation collection mechanism also includes a solenoid valve 28, which is arranged on the pipeline connecting the screw conveyor 27 and the collection box 29, and is used to control the opening and closing of the pipeline. It can realize intermittent automatic collection of solid by-products by timed opening, which is convenient for subsequent recycling.

[0036] In some preferred embodiments, a pressure control valve 25 is further provided on the pipeline connecting the second gas outlet 23 and the subsequent dehydration link. The pressure control valve 25 can stabilize the pressure inside the reaction unit 2 within a fixed range to ensure the progress of the reaction. When the amount of reaction by-product gas increases and the pressure exceeds the upper limit of the pressure value, the valve automatically opens to release excess gas.

[0037] In some preferred embodiments, a one-way valve 26 is further provided on the pipeline connecting the second gas outlet 23 and the subsequent dehydration link. The one-way valve 26 is located on the side of the pressure control valve 25 away from the second gas outlet 23, and can prevent other natural gas such as the dehydration link from flowing back into the reaction unit 2 through the one-way conduction design.

[0038] In some preferred embodiments, the number of the reaction units 2 can be 1, 2 or more. When the number of the reaction units 2 is 2 or more, the reaction units 2 are connected in series, that is, the second liquid outlet 24 of the first reaction unit 2 is connected to the second liquid inlet 22 of the second reaction unit 2 adjacent to it, and so on, forming a series connection together to further perform a neutralization reaction on the acid-rich gas absorption liquid, further remove residual impurities in the absorption liquid, and obtain a more standard purified liquid for discharge.

[0039] In some preferred embodiments, the natural gas desulfurization device also includes a liquid distribution unit 3, which is connected in series with the reaction unit 2. Specifically, when there are two or more reaction units 2, the liquid distribution unit 3 is connected after the last reaction unit 2; specifically, the liquid distribution unit 3 includes a third liquid inlet 31 and a third liquid outlet 32, and the third liquid inlet 31 is connected to the second liquid outlet 24 of the adjacent reaction unit 2 (i.e., the last reaction unit 2) for receiving purified liquid, and the third liquid outlet 32 ​​is connected to the first liquid inlet 12 and / or the discharge system of the desulfurization unit 1 to achieve recycling or discharge of the purified liquid.

[0040] In some preferred embodiments, a second liquid level monitoring component 33 is further provided in the liquid distribution unit 3, which is used to monitor the liquid level of the internal purified liquid and control the opening and closing of the passage corresponding to the third liquid outlet 32 ​​according to the liquid level signal. In some specific embodiments, the second liquid level monitoring component 33 includes a second upper liquid level gauge and a second lower liquid level gauge. When the liquid level reaches the second upper liquid level gauge, the passage connected to the third liquid outlet 32 ​​is opened (such as by turning on a water pump arranged on the passage) to discharge the purified liquid or enter the desulfurization unit for recycling. When the liquid level drops to the second lower liquid level gauge, the passage is closed.

[0041] On the other hand, the present application also provides a natural gas desulfurization method, which specifically comprises the following steps: S1, acid gas dissolution stage: the natural gas to be desulfurized is brought into countercurrent contact with the desulfurization medium to dissolve the acid gas in the natural gas to generate an acid gas-rich absorption liquid and obtain desulfurized natural gas at the same time; Wherein, the desulfurization medium is water; the countercurrent contact specifically refers to the contact zone formed by the desulfurization medium flowing from top to bottom and the natural gas to be desulfurized flowing from bottom to top; the acid gas in the natural gas specifically refers to and The acid gas-rich absorption liquid specifically refers to the dissolved and of water; Specifically, the water in S1 reacts with the acidic gas as follows: ; Preferably, the volume flow ratio of water to the natural gas to be desulfurized in S1 is 1:1-1:10 to ensure that the acid gas can be fully dissolved; Preferably, the S1 further involves pre-dehydration treatment of the natural gas. In some optional embodiments, the pre-dehydration treatment specifically refers to setting a metal ball packing layer in the countercurrent contact area, utilizing the contact condensation between the natural gas and the metal balls to remove the water vapor carried in the natural gas, and the condensed water falls and is discharged with the acid-rich gas absorption liquid; in some other optional embodiments, the pre-dehydration treatment specifically refers to setting a condenser at the top of the countercurrent contact area to further remove the water entrained in the desulfurized natural gas. Specifically, the condenser can be a plate condenser or other equipment capable of achieving water vapor separation. The specific selection can be based on the actual processing capacity and working conditions, and is not specifically limited here; in some other optional embodiments, the above-mentioned pre-dehydration treatment can be set at the same time; S2, neutralization reaction stage: mixing the acidic gas absorption liquid with the alkaline solid reactant to perform a neutralization reaction to generate a mixed slurry containing solid by-products and reaction by-product gas; Specifically, the alkaline solid reactant can be selected from limestone ( )、Carbide slag( ) and other energy The substance that reacts to form a precipitate of insoluble metal sulfide, preferably, the alkaline solid reactant is limestone.

[0042] Preferably, when the alkaline solid reactant is limestone, the acidic gas absorbing liquid in S2 reacts with the alkaline solid reactant as follows: Formula (2.1); Formula (2.2); ; That is, the solid by-product is The reaction by-product gas is precipitated Dissolved in acid gas absorption liquid Recycling in the reaction chain; Preferably, when the alkaline solid reactant is limestone, the mass flow ratio of the limestone to the natural gas to be desulfurized is greater than 1:10. This is because a side reaction such as equation (2.4) will also occur in S2, and this reaction can be suppressed when there is sufficient limestone, that is, excessive limestone can make the solution , inhibiting the hydrolysis of calcium sulfide and keeping it in the form of solid precipitate. More preferably, the mass flow ratio of limestone to natural gas to be desulfurized is 1:1 to 1:10. Within this ratio range, it can ensure that there is enough limestone to inhibit the hydrolysis side reaction of calcium sulfide shown in formula (2.4) and avoid Secondary precipitation leads to a decrease in desulfurization efficiency, ensuring that solid by-products It exists stably and is collected efficiently; it can also avoid waste and solid accumulation caused by excessive limestone, and reduce the load of subsequent solid-liquid separation.

[0043] S3, separation and treatment stage: separating the solid precipitate in the mixed slurry for recovery, recycling the purified liquid to step S1 or discharging, and transporting the reaction by-product gas to the dehydration stage; In some specific embodiments, the natural gas desulfurization method can be implemented using the natural gas desulfurization device provided above, and the specific implementation process is as follows: The natural gas to be desulfurized is introduced into the desulfurization unit 1 through the first air inlet 13. Water, serving as the desulfurization medium, is introduced through the first liquid inlet 12. The first liquid inlet 12 and the first air inlet 13 are located on the same side of the unit, and the first liquid outlet 14 is radially opposed to the first air inlet 13. The liquid level within the desulfurization unit 1 is controlled to always be above the upper edge of the first air inlet 13, so that the natural gas to be desulfurized directly enters the water. The volumetric flow rate ratio of water to natural gas to be desulfurized is controlled to be between 1:1 and 1:10 (at room temperature), creating a countercurrent flow of water from top to bottom and natural gas from bottom to top.

[0044] If a metal ball packing layer 15 is provided in the desulfurization unit 1 (located between the first liquid inlet 12 and the first gas inlet 13), when the desulfurized natural gas rises, it will drive the metal balls to rotate in place or slightly displace (the lifting force of the natural gas is not enough to lift them up), forming turbulence to increase the gas-liquid contact area and time; at the same time, the water vapor carried in the natural gas will adhere to the surface of the metal balls. When the water from the first liquid inlet 12 flows to the metal balls, it will flush the water and dissolved acidic gas attached to the surface of the balls and make them flow into the bottom liquid pool, further improving the gas-liquid contact area. dissolution efficiency and preliminary removal of carried water vapor.

[0045] The desulfurized natural gas continues to rise, passes through the condenser 16 to further remove the entrained water to reduce the subsequent dehydration pressure, and is finally discharged from the first gas outlet 11. The acid gas absorption liquid at the bottom of the desulfurization unit 1 (dissolved ) is discharged through the first liquid outlet 14, and its liquid level is controlled by a water pump in conjunction with the upper and lower liquid level gauges: when the liquid level reaches the upper liquid level gauge, the water pump speeds up the drainage speed; when it drops to the lower liquid level gauge, the water pump slows down the drainage speed to ensure that the liquid level is always higher than the first air inlet 13 and to avoid water backflow. The acid gas-rich absorption liquid is transported to the second liquid inlet 22 of the reaction unit 2 through a pipeline.

[0046] In the reaction unit 2, an alkaline solid reactant (preferably limestone, with a mass flow ratio of the reactant to the natural gas to be desulfurized greater than 1:10) is added through the reactant inlet 21. A series of reactions, including neutralization, occur with the acidic gas absorption liquid to generate byproduct gases such as methane, which are precipitated due to the increase in water temperature. The byproduct gases are discharged from the second gas outlet 23 and transported to the subsequent dehydration step through a pipeline (equipped with a pressure control valve 25 and a one-way valve 26. The pressure control valve 25 opens when the gas pressure in the container reaches the set pressure, and the one-way valve 26 prevents gas backflow).

[0047] The reaction 、 Insoluble solid by-products such as the above-mentioned solid by-products settle and gather at the conical bottom of the reaction unit 2 and are transported to the collection box 29 by the screw conveyor 27 (preferably, the electromagnetic valve 28 is opened at a fixed time to achieve intermittent discharge for easy recycling); the purified liquid after the neutralization reaction flows out through the second liquid outlet 24 and enters the liquid distribution unit 3, and can be recycled to the desulfurization unit 1 or discharged in compliance with the standards.

[0048] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications can be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A new type of natural gas desulfurization device, characterized in that: include: A desulfurization unit (1) is used to bring a desulfurization medium into countercurrent contact with the natural gas to be desulfurized to dissolve the acid gas, and to output the desulfurized natural gas and the acid gas-rich absorption liquid respectively; A reaction unit (2) is used to receive the acidic gas absorption liquid and neutralize it with the alkaline solid reactant to generate a mixed slurry containing solid by-products, and output the solid precipitate, purified liquid and reaction by-product gas respectively; The desulfurization medium is water, and the first liquid outlet (14) of the desulfurization unit (1) is connected to the second liquid inlet (22) of the reaction unit (2).

2. The new natural gas desulfurization device according to claim 1 is characterized in that: The desulfurization unit (1) comprises a first gas outlet (11) arranged at the top, and a first liquid inlet (12), a first gas inlet (13), and a first liquid outlet (14) arranged on the side wall in order from top to bottom; The height of the first air inlet (13) is lower than the liquid level in the desulfurization unit (1).

3. The new natural gas desulfurization device according to claim 2 is characterized in that: A metal ball packing layer (15) is further provided inside the desulfurization unit (1). The metal ball packing layer (15) is composed of a plurality of arranged metal balls and is located between the first liquid inlet (12) and the first gas inlet (13).

4. The new natural gas desulfurization device according to claim 3 is characterized in that: The number of the metal ball filling layers (15) is at least one, and two adjacent metal ball filling layers (15) are spaced apart in the vertical direction; And / or, the metal ball is a hollow sphere; And / or, the metal ball is made of stainless steel.

5. The new natural gas desulfurization device according to claim 3 is characterized in that: The desulfurization unit (1) is further provided with a condenser (16) at the top end thereof for removing water entrained in the desulfurized natural gas; And / or, the desulfurization unit (1) is further provided with a first liquid level monitoring component (17) for monitoring the liquid level to ensure that the liquid level in the desulfurization unit (1) is always higher than the first air inlet (13).

6. The new natural gas desulfurization device according to claim 1 is characterized in that: The reaction unit (2) comprises a reactant inlet (21) and a second gas outlet (23) arranged at the top, and a second liquid inlet (22) and a second liquid outlet (24) arranged at the side wall, and a sediment collection mechanism is provided at the bottom of the reaction unit (2) for collecting and discharging solid sediment; And / or, the number of the reaction unit (2) is at least one, and when the number is greater than one, the reaction units (2) are arranged in series.

7. The new natural gas desulfurization device according to claim 1 is characterized in that: The invention also includes a liquid distribution unit (3) connected in series with the reaction unit (2), wherein the liquid distribution unit (3) includes a third liquid inlet (31) and a third liquid outlet (32), wherein the third liquid inlet (31) is connected to the second liquid outlet (24) of the reaction unit (2) for receiving the purified liquid; and the third liquid outlet (32) is connected to the first liquid inlet (12) and / or the discharge system of the desulfurization unit (1) to realize recycling or discharge of the purified liquid. A second liquid level monitoring component (33) is provided in the liquid distribution unit (3) for monitoring the liquid level of the purified liquid and controlling the flow rate of the pipeline corresponding to the third liquid outlet (32) according to the liquid level signal.

8. A natural gas desulfurization method, characterized in that: The following steps are involved: S1, bringing the natural gas to be desulfurized into countercurrent contact with the desulfurization medium to dissolve the acid gas in the natural gas to generate an acid gas-rich absorption liquid, and simultaneously obtain desulfurized natural gas; S2, mixing the acid gas-rich absorption liquid with the alkaline solid reactant to perform a neutralization reaction to generate a mixed slurry containing solid by-products and reaction by-product gas; S3, separating the solid precipitate in the mixed slurry for recovery, recycling the purified liquid to step S1 or discharging it, and transporting the reaction by-product gas to the dehydration stage; Wherein, the desulfurization medium is water.

9. The natural gas desulfurization method according to claim 8, characterized in that: The volume flow ratio of the water to the natural gas to be desulfurized is 1:1 to 1:10; And / or, the alkaline solid reactant is limestone, and the mass flow ratio of the alkaline solid reactant to the natural gas to be desulfurized is greater than 1:

10.

10. The natural gas desulfurization method according to claim 8, characterized in that: Said S1 also involves pre-dehydration treatment of natural gas, said pre-dehydration treatment comprising: A metal ball packing layer is set in the countercurrent contact area, and the water vapor carried in the natural gas is removed by condensation through contact between the natural gas and the metal balls. The condensed water falls and is discharged with the acid gas-rich absorption liquid; And / or, a condenser is provided at the top of the countercurrent contact area to further remove water entrained in the desulfurized natural gas.

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