阅读说明：本技术 一种升级天然气质量的方法和装置 (Method and device for upgrading natural gas quality ) 是由 朱慧 周志斌 朱学田 于 2020-10-23 设计创作，主要内容包括：本发明提供一种升级天然气质量的方法和装置,具体包括以下步骤：原料天然气先经过醇胺法装置脱除大量的H-2S和适量的CO-2,得到半脱硫脱碳气；半脱硫脱碳气经过水解催化剂作用,几乎全部的COS/CS-2水解成H-2S和CO-2,得到脱COS/CS-2半产品气；脱COS/CS-2半产品气经过精脱硫装置,强碱水溶液的洗涤,残余的H-2S、COS和几乎全部的RSH也被脱除,得到了脱硫产品气；脱硫产品气经过三甘醇脱水则得到质量升级后的产品气。本发明技术方案对于现有脱硫装置升级天然气质量指标,仅需增加COS/CS-2水解和精脱硫单元,大部分脱除的RSH转化为二硫化物且可作为高价值副产品外售。(The invention provides a method and a device for upgrading the quality of natural gas, which specifically comprise the following steps: raw material natural gas is subjected to alcohol amine method device to remove a large amount of H 2 S and appropriate amount of CO 2 Obtaining semi-desulfurization and decarburization gas; the semi-desulfurization and decarbonization gas is acted by a hydrolysis catalyst, and almost all COS/CS 2 Hydrolysis to H 2 S and CO 2 To obtain the COS/CS removed 2 Semi-product gas; removing COS/CS 2 Passing the semi-product gas through a fine desulfurization device, washing with strong alkaline water solution, and removing residual H 2 S, COS and almost all RSH are also removed, resulting in a desulfurized product gas; and dehydrating the desulfurized product gas by using triethylene glycol to obtain the product gas with upgraded quality. According to the technical scheme, only COS/CS (COS/CS) is required to be added for upgrading the quality index of the natural gas of the conventional desulfurization device 2 Hydrolysis and fine desulfurization units, most of the removed RSH is converted to disulfides and can be sold as a high value byproduct.)

1. A method for upgrading the quality of natural gas, characterized by: the method comprises the following steps:

the method comprises the following steps: the method comprises the following steps of (1) enabling raw material natural gas to pass through an alcohol amine method desulfurization and decarburization unit to obtain semi-desulfurization and decarburization gas and residual gas; h in the obtained semi-desulfurization and decarburization gas₂S is removed to<200mg/m3, preferably<100mg/m3, most preferably<50mg/m 3; content of CO2<4%, preferably CO₂In an amount of<3%, most preferably CO₂In an amount of<2%；

Step two: introducing the semi-desulfurized and decarbonized gas to COS/CS₂Hydrolysis reaction unit to obtain COS/CS removed₂Semi-product gas; the COS/CS₂The hydrolysis reaction unit is humidified and adjusted in temperature by spraying saturated steam or deoxygenated water in a bubbling mode, separated from free liquid by a separation tank and led to a COS/CS2 hydrolysis reactor to generate COS/CS removal₂Semi-product gas;

step three: will remove COS/CS₂Leading the semi-product gas to a fine desulfurization unit; leading the liquid to a fine desulfurization device after temperature regulation and separation of free liquid in a fine desulfurization unit; the fine desulfurization device comprises a washing device of strong alkali aqueous solution; thereby obtaining a desulfurization product gas;

step four: passing the desulfurized product gas through a dehydration unit; and the dehydration unit adopts triethylene glycol for dehydration to obtain product gas.

2. A method of upgrading natural gas quality according to claim 1, characterized in that: COS/CS in step two₂The hydrolysis reaction temperature of the hydrolysis reactor is 60-200 ℃; preferably 90 to 160 ℃, and most preferably 110 to 140 ℃; the three ranges of the hydrolysis reaction temperature respectively correspond to the gas saturation humidity in sequence45-160 ℃, 70-140 ℃ and 100-130 ℃.

3. A method of upgrading natural gas quality according to claim 1, characterized in that: removing COS/CS in the third step₂The temperature regulation range of the semi-product gas is 40-50 ℃, and the temperature regulation method comprises gas heat exchange, air cooling or water cooling of an inlet and an outlet of the hydrolysis reactor.

4. A method of upgrading natural gas quality according to claim 1, characterized in that: and in the third step, the alkali liquor used in the washing device of the strong alkali aqueous solution is a sodium hydroxide or potassium hydroxide aqueous solution, wherein the mass fraction range of the alkali is 10-30%.

5. A method of upgrading natural gas quality according to claim 1, characterized in that: 50-300 ppmv of alkali liquor regeneration catalyst is contained in the alkali liquor in the washing device of the strong alkali aqueous solution in the third step; leading residual liquid output by a washing device of the strong alkali aqueous solution to an oxidation tower to realize alkali liquor regeneration; the regenerated alkali liquor is led to the fine desulfurization device again after being subjected to disulfide separation, dissolved oxygen removal, desalination and filtration.

6. A method of upgrading natural gas quality according to claim 1, characterized in that: in the first step, H is contained generated by the desulfurization and decarbonization unit by the alcohol amine method₂S or/and CO₂The residual gas is processed by a sulfur recovery device to recover sulfur element in the form of sulfur or is processed and injected underground.

7. A method of upgrading natural gas quality according to claim 1, characterized in that: COS/CS in step two₂And (3) carrying out oxidation regeneration and disulfide separation on the sulfide-containing alkali liquor generated by the hydrolysis reaction unit to obtain fresh alkali liquor, and sending the fresh alkali liquor to a fine desulfurization device for recycling after dissolved oxygen removal, desalting and filtering treatment.

8. A method of upgrading natural gas quality according to claim 5, characterized in that: the regeneration catalyst is composed of metal cobalt phthalocyanine or cobalt phthalocyanine and one or two of monoethanolamine, ammonium chloride, urea, cobalt polybutanethiol and morpholine.

9. A method of upgrading natural gas quality according to claim 5, characterized in that: and (3) further purifying and refining the disulfide separated from the oxidation tower by using C6-C11 heavy hydrocarbon, preferably heavy naphtha.

10. An apparatus for upgrading natural gas quality using a method of upgrading natural gas quality as claimed in any one of claims 1 to 7; the method is characterized in that: comprises an alcohol amine method desulfurization and decarbonization unit, COS/CS₂The device comprises a hydrolysis reaction unit, a fine desulfurization unit, a dehydration unit, a sulfur recovery or reinjection unit and a sulfur dioxide refining unit;

the alcohol amine method desulfurization and decarburization unit is used for performing selective desulfurization on raw material natural gas from an upstream filter at about 30-40 ℃ by using the alcohol amine method desulfurization and decarburization device to obtain semi-desulfurization and decarburization gas and H-containing gas₂S or/and CO₂The residual gas of (3); containing H₂S or/and CO₂The residual gas is led to a sulfur recovery or reinjection unit for recovery treatment;

the COS/CS₂The hydrolysis reaction unit is used for leading the semi-desulfurization and decarburization gas to pass through the hydrolysis reactor and leading almost all COS/CS₂Hydrolysis of H₂S and CO₂To obtain the COS/CS removed₂Semi-product gas;

the fine desulfurization unit is used for removing COS/CS₂Introducing the semi-product gas into alkali liquor to generate desulfurized product gas and residual liquid; leading the residual liquid to a sulfur dioxide refining unit for alkali liquor regeneration, and leading the regenerated alkali liquor to a fine desulfurization device of a fine desulfurization unit again after disulfide separation, dissolved oxygen removal, desalination and filtration;

the dehydration unit is used for dehydrating the desulfurization product gas to obtain the product gas.

Technical Field

The invention relates to the technical field of natural gas purification treatment, in particular to a method and a device for upgrading the quality of natural gas.

Background

Natural gas is used as a high-quality, high-efficiency and clean low-carbon energy and chemical raw material, and the resource status of the natural gas is increasingly prominent. The apparent consumption of natural gas is increased by 9 percent in 2019 years in China, and the production of natural gas is increased by 9.9 percent. Nevertheless, the domestic natural gas yield still can not keep up with the leap-type growth of demand, and the dependence degree of natural gas to the outside is as high as 44%, and a large amount of inferior natural gas containing sulfur, high sulfur content and the like still need to be developed in a large quantity. Therefore, the primary measures for the development of the natural gas industry in China still stably improve the domestic oil and gas exploration and development strength, guarantee the natural gas supply and control the external dependence at a reasonable level. On the other hand, as a primary energy source for converting new and old kinetic energy and improving the environmental quality, the natural gas quality of China is further improved by the nation to meet the requirements of users and the environment under the background of vigorous natural gas demand of China. The promulgation of the current natural gas (GB17820-2018) standard requires the natural gas H entering a long-distance pipeline₂S＜6mg/m³Total sulfur less than 20mg/m³(ii) a H relative to original (GB 17820-2012)₂S＜20mg/m³Total sulfur less than 200mg/m^3，The quality requirements are more strict. According to the standard of natural gas (GB17820-2018), the total sulfur of the target time of the middle and long term in China is controlled to be 8mg/m³That is, the quality standard of natural gas will be further upgraded in the future, and the total sulfur is reduced to less than 10mg/m³Or even lower, there is a pressing need for production methods and apparatus that improve the quality of natural gas.

In natural gas purification process, alcohol amine method is widely used for removing CO in acidic natural gas₂And H₂And S. The currently used alcohol amine solvents are mainly N-Methyldiethanolamine (MDEA) and various formulation solvents of MDEA. Overall, the alcohol amine process is applied to COS and CS of natural gas₂And the removal degree of RSH is limited, so that the sulfur content of product gas is difficult to meet the natural gas (GB 17820-2018). Albeit for COS, CS₂It can be converted into H industrially by hydrolysis₂S、CO₂And then removed, e.g. by converting COS in the gas stream to H using a solid hydrolysing agent as mentioned in EP1791622A1₂S and CO₂. It is also possible to use CN101175547B to propose the use of iron oxides at certain preferred temperatures, pressures and space velocitiesThe fine desulfurization of COS in the current gas stream. No matter hydrolysis or fine iron oxide desulfurization, the RSH content cannot be effectively reduced. RSH can be removed industrially by molecular sieve methods, such as CA2614169A1, but molecular sieves will work for H₂S、COS、CS₂There is also adsorption, for which a large amount of purified commodity gas is consumed as regeneration gas to regenerate the molecular sieve. Meanwhile, the commercial natural gas entering the long-distance pipeline needs to be controlled to have a reasonable dew point, and the commercial natural gas is dehydrated by a triethylene glycol method.

Therefore, in order to meet more stringent natural gas quality standards, a purification method and apparatus that upgrades the quality of existing natural gas is urgently needed.

Disclosure of Invention

1. The technical problem to be solved is as follows:

aiming at the technical problems, the invention provides a method and a device for upgrading the quality of natural gas, according to the composition of the natural gas, the method and the device can reasonably and effectively remove sulfide and carbon dioxide in the natural gas, and simultaneously control the dew point of the natural gas to ensure that the natural gas has H₂S content less than 2mg/m³Total sulfur less than 10mg/m³Thus, the natural gas is a high-quality commodity natural gas meeting the relevant regulations.

2. The technical scheme is as follows:

a method for upgrading the quality of natural gas, characterized by: the method comprises the following steps:

the method comprises the following steps: the method comprises the following steps of (1) enabling raw material natural gas to pass through an alcohol amine method desulfurization and decarburization unit to obtain semi-desulfurization and decarburization gas and residual gas; h in the obtained semi-desulfurization and decarburization gas₂S is removed to<200mg/m3, preferably<100mg/m3, most preferably<50 mg/m3；CO₂In an amount of<4%, preferably CO₂In an amount of<3%, most preferably CO₂In an amount of<2%。

Step two: introducing the semi-desulfurized and decarbonized gas to COS/CS₂Hydrolysis reaction unit to obtain COS/CS removed₂Semi-product gas; the COS/CS₂The hydrolysis reaction unit is firstly humidified and adjusted in temperature by a bubbling mode of spraying saturated steam or deoxygenated water, and then is led to COS/CS after being separated out of free liquid by a separation tank₂Hydrolysis reactor to produce COS/CS₂Half-yieldAnd (4) tasting qi.

Step three: will remove COS/CS₂Leading the semi-product gas to a fine desulfurization unit; leading the liquid to a fine desulfurization device after temperature regulation and separation of free liquid in a fine desulfurization unit; the fine desulfurization device comprises a washing device of strong alkali aqueous solution; thereby obtaining the desulfurization product gas.

Step four: passing the desulfurized product gas through a dehydration unit; and the dehydration unit adopts triethylene glycol for dehydration to obtain product gas.

Further, COS/CS in step two₂The hydrolysis reaction temperature of the hydrolysis reactor is 60-200 ℃; preferably 90 to 160 ℃, and most preferably 110 to 140 ℃; the three ranges of the hydrolysis reaction temperature respectively correspond to gas saturation humidity of 45-160 ℃, 70-140 ℃ and 100-130 ℃.

Further, removing COS/CS in the third step₂The temperature regulation range of the semi-product gas is 40-50 ℃, and the temperature regulation method comprises gas heat exchange, air cooling or water cooling of an inlet and an outlet of the hydrolysis reactor.

Further, the alkali liquor used in the washing device of the strong alkali aqueous solution in the third step is a sodium hydroxide or potassium hydroxide aqueous solution, wherein the mass fraction range of the alkali is 10-30%.

Further, 50-300 ppmv of alkali liquor regeneration catalyst is contained in an alkali solution in the washing device of the alkali liquor in the third step; leading residual liquid output by a washing device of the strong alkali aqueous solution to an oxidation tower to realize alkali liquor regeneration; the regenerated alkali liquor is led to the fine desulfurization device again after being subjected to disulfide separation, dissolved oxygen removal, desalination and filtration.

Further, in the step one, H is contained generated by the alcohol amine method desulfurization and decarbonization unit₂S or/and CO₂The residual gas is processed by a sulfur recovery device to recover sulfur element in the form of sulfur or is processed and injected underground.

Further, COS/CS in step two₂And (3) carrying out oxidation regeneration and disulfide separation on the sulfide-containing alkali liquor generated by the hydrolysis reaction unit to obtain fresh alkali liquor, and sending the fresh alkali liquor to a fine desulfurization device for recycling after dissolved oxygen removal, desalting and filtering treatment.

Furthermore, the regenerated catalyst is composed of metal cobalt phthalocyanine or cobalt phthalocyanine and one or two of monoethanolamine, ammonium chloride, urea, cobalt polybutanethiol and morpholine.

Further, the disulfide separated from the oxidation tower is further purified and refined through C6-C11 heavy hydrocarbon, preferably heavy naphtha.

A device for upgrading the quality of natural gas comprises an alcohol amine method desulfurization and decarburization unit, a COS/CS2 hydrolysis reaction unit, a fine desulfurization unit, a dehydration unit, a sulfur recovery or reinjection unit and a sulfur dioxide refining unit.

The alcohol amine method desulfurization and decarburization unit is used for performing selective desulfurization on raw material natural gas from an upstream filter at about 30-40 ℃ by using the alcohol amine method desulfurization and decarburization device to obtain semi-desulfurization and decarburization gas and H-containing gas₂S or/and CO₂The residual gas of (3); containing H₂S or/and CO₂The residual gas is led to a sulfur recovery or reinjection unit for recovery treatment.

And the COS/CS2 hydrolysis reaction unit is used for passing the semi-desulfurization and decarbonization gas through the hydrolysis reactor, and hydrolyzing almost all COS/CS2 into H2S and CO2 to obtain a semi-product gas of the decarbonization of COS/CS 2.

The fine desulfurization unit is used for introducing the semi-product gas subjected to COS/CS2 removal into alkali liquor to generate desulfurized product gas and residual liquid; and leading the residual liquid to a sulfur dioxide refining unit for alkali liquor regeneration, and leading the regenerated alkali liquor to a fine desulfurization device of a fine desulfurization unit again after disulfide separation, dissolved oxygen removal, desalination and filtration.

The dehydration unit is used for dehydrating the desulfurization product gas to obtain the product gas.

3. Has the advantages that:

(1) the scheme provided by the invention realizes the quality upgrade of the product gas of the existing device, and under the condition of keeping the existing alcohol amine desulfurization and decarbonization device, the COS/CS2 hydrolysis reaction unit, the fine desulfurization unit and the dehydration unit are added according to specific conditions, and the alkali liquor is recycled, so that the consumption is low, and simultaneously, RSH is converted into disulfide which can be used as a high-value product for sale.

(2) In the scheme, the H content of the semi-desulfurization and decarburization gas is controlled₂Amount of S, CO content₂The requirement of the product gas with different quality requirements can be realized in different ranges of quantity, and the COS/CS is simultaneously used₂The hydrolysis reaction temperature, hydrolysis reaction humidity in the hydrolysis reactor also provide different ranges.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

As shown in fig. 1, a method for upgrading natural gas quality is characterized in that: the method comprises the following steps:

the method comprises the following steps: the method comprises the following steps of (1) enabling raw material natural gas to pass through an alcohol amine method desulfurization and decarburization unit to obtain semi-desulfurization and decarburization gas and residual gas; h in the obtained semi-desulfurization and decarburization gas₂S is removed to<200mg/m3, preferably<100mg/m3, most preferably<50 mg/m3；CO₂In an amount of<4%, preferably CO₂In an amount of<3%, most preferably CO₂In an amount of<2%。

The method can reasonably and effectively remove sulfide and carbon dioxide in the natural gas according to the composition of the natural gas, and control the dew point of the natural gas to enable the natural gas to become high-quality commodity gas. In the step, raw material natural gas is subjected to alcohol amine method desulfurization and decarbonization unit to remove a large amount of H₂S and appropriate amount of CO₂To obtain the semi-desulfurization and decarburization gas. The raw material natural gas from the upstream filter is about 30-40 ℃, and the raw material natural gas is subjected to selective desulfurization by an alcohol amine method desulfurization and decarbonization device to obtain H in semi-desulfurization and decarbonization gas₂S is removed to<200mg/m³Preferably, the<100mg/m³Most preferably, it is<50 mg/m³，CO₂In an amount of<4%, preferably CO₂In an amount of<3%, most preferably CO₂In an amount of<2 percent. Three criteria are provided and can be selected according to the quality requirements of the product gas.

Step two: introducing the semi-desulfurized and decarbonized gas to COS/CS₂Hydrolysis reaction unit to obtain COS/CS removed₂Semi-product gas; the COS/CS₂The hydrolysis reaction unit is firstly humidified and adjusted in temperature by a bubbling mode of spraying saturated steam or deoxygenated water, and then is led to COS/CS after being separated out of free liquid by a separation tank₂HydrolysisReactor generation for COS/CS removal₂And (5) semi-product gas.

Step three: will remove COS/CS₂Leading the semi-product gas to a fine desulfurization unit; leading the liquid to a fine desulfurization device after temperature regulation and separation of free liquid in a fine desulfurization unit; the fine desulfurization device comprises a washing device of strong alkali aqueous solution; thereby obtaining the desulfurization product gas.

In this step, COS/CS is removed₂The semi-product gas is washed by low-concentration strong alkaline aqueous solution in a fine desulfurization device to remove COS/CS₂Residual H in semi-product gas₂S, COS are further removed and substantially all of the RSH is removed to produce a sweet product gas.

Step four: passing the desulfurized product gas through a dehydration unit; and the dehydration unit adopts triethylene glycol for dehydration to obtain product gas.

The product of the step is high-quality product gas which meets the existing quality requirement or is higher than the existing quality requirement.

Further, COS/CS in step two₂The hydrolysis reaction temperature of the hydrolysis reactor is 60-200 ℃; preferably 90 to 160 ℃, and most preferably 110 to 140 ℃; the three ranges of the hydrolysis reaction temperature respectively correspond to gas saturation humidity of 45-160 ℃, 70-140 ℃ and 100-130 ℃.

Further, removing COS/CS in the third step₂The temperature regulation range of the semi-product gas is 40-50 ℃, and the temperature regulation method comprises gas heat exchange, air cooling or water cooling of an inlet and an outlet of the hydrolysis reactor.

Further, the alkali liquor used in the washing device of the strong alkali aqueous solution in the third step is a sodium hydroxide or potassium hydroxide aqueous solution, wherein the mass fraction range of the alkali is 10-30%.

Further, 50-300 ppmv of alkali liquor regeneration catalyst is contained in an alkali solution in the washing device of the alkali liquor in the third step; leading residual liquid output by a washing device of the strong alkali aqueous solution to an oxidation tower to realize alkali liquor regeneration; the regenerated alkali liquor is led to the fine desulfurization device again after being subjected to disulfide separation, dissolved oxygen removal, desalination and filtration.

Further, in the step one, alcohol amineH-containing gas produced in a desulfurization and decarbonization unit₂S or/and CO₂The residual gas is processed by a sulfur recovery device to recover sulfur element in the form of sulfur or is processed and injected underground.

Further, COS/CS in step two₂And (3) carrying out oxidation regeneration and disulfide separation on the sulfide-containing alkali liquor generated by the hydrolysis reaction unit to obtain fresh alkali liquor, and sending the fresh alkali liquor to a fine desulfurization device for recycling after dissolved oxygen removal, desalting and filtering treatment.

Furthermore, the regenerated catalyst is composed of metal cobalt phthalocyanine or cobalt phthalocyanine and one or two of monoethanolamine, ammonium chloride, urea, cobalt polybutanethiol and morpholine.

Further, the disulfide separated from the oxidation tower is further purified and refined through C6-C11 heavy hydrocarbon, preferably heavy naphtha.

A device for upgrading the quality of natural gas comprises an alcohol amine method desulfurization and decarburization unit, a COS/CS2 hydrolysis reaction unit, a fine desulfurization unit, a dehydration unit, a sulfur recovery or reinjection unit and a sulfur dioxide refining unit.

The alcohol amine method desulfurization and decarburization unit is used for performing selective desulfurization on raw material natural gas from an upstream filter at about 30-40 ℃ by using the alcohol amine method desulfurization and decarburization device to obtain semi-desulfurization and decarburization gas and H-containing gas₂S or/and CO₂The residual gas of (3); containing H₂S or/and CO₂The residual gas is led to a sulfur recovery or reinjection unit for recovery treatment.

COS/CS₂And the hydrolysis reaction unit is used for leading the semi-desulfurization and decarbonization gas to pass through the hydrolysis reactor, and hydrolyzing almost all COS/CS2 into H2S and CO2 to obtain the COS/CS2 removed semi-product gas.

The fine desulfurization unit is used for removing COS/CS₂Introducing the semi-product gas into alkali liquor to generate desulfurized product gas and residual liquid; and leading the residual liquid to a sulfur dioxide refining unit for alkali liquor regeneration, and leading the regenerated alkali liquor to a fine desulfurization device of a fine desulfurization unit again after disulfide separation, dissolved oxygen removal, desalination and filtration.

The dehydration unit is used for dehydrating the desulfurization product gas to obtain the product gas.

The specific embodiment is as follows:

example 1:

the pressure of the natural gas used in the test is 5.0MPa, and the volume fraction of the main component is H₂S 2.0%、CO₂ 5.0%、COS+CS₂50mg/m in terms of sulfur³And the balance being methane. Raw material natural gas enters an alcohol amine desulphurization and decarbonization unit at 35-40 ℃, and H in semi-desulphurization and decarbonization gas is obtained after desulphurization and decarbonization by using an MDEA solution₂S content about 3mg/m³、COS+CS₂About 40 mg/m in terms of sulfur³、CO₂Is about 2.7%. After heat exchange and humidification, the gas enters a hydrolysis reactor at the temperature of 120 ℃ and the humidity of 110 ℃, and the gas at the outlet of the hydrolysis reactor enters a fine desulfurization unit after heat exchange and cooling to 40 ℃ and separation of free liquid. In the fine desulfurization unit, after being washed by sodium hydroxide alkali liquor with the mass fraction of 18 percent, the H in the desulfurization product gas₂S content<0.1mg/m³2.8 mg/m of total sulfur³、CO₂The content of (2.5%) can be directly fed into triethylene glycol dehydration unit to obtain dew point<-10 ℃ of product gas. The alkali liquor also contains 0.01 percent of sulfonated cobalt phthalocyanine and 0.1 percent of ammonium chloride by mass.

Example 2:

the pressure of the natural gas used in the test is 5.0MPa, and the volume fraction of the main component is H₂S 2.0%、CO₂5.0% and RSH 50mg/m in terms of sulfur³And the balance being methane. Raw material natural gas enters an alcohol amine desulphurization and decarbonization unit at 35-40 ℃, and H in semi-desulphurization and decarbonization gas is obtained after desulphurization and decarbonization by using an MDEA solution₂S content about 3mg/m³RSH is about 47 mg/m in terms of sulfur³、CO₂Is about 2.7%. After separating free liquid, the liquid enters a fine desulfurization unit. In the fine desulfurization unit, after being washed by sodium hydroxide alkali liquor with the mass fraction of 20 percent, the H in the desulfurization product gas₂S content<0.1mg/m³3.1 mg/m of total sulfur³、CO₂The content of (2.5%) can be directly fed into triethylene glycol dehydration unit to obtain dew point<-10 ℃ of product gas. The alkali liquor also contains 0.01 percent of sulfonated cobalt phthalocyanine and 0.1 percent of ammonium chloride by mass.

Example 3:

the pressure of the natural gas used in the test is 5.0MPa, and the volume fraction of the main component is H₂S 5.0%、CO₂ 6.0%、COS+CS₂100mg/m in terms of sulfur³RSH is 30mg/m in terms of sulfur³And the balance being methane. Raw material natural gas enters an alcohol amine desulphurization and decarbonization unit at 35-40 ℃, and H in semi-desulphurization and decarbonization gas is obtained after desulphurization and decarbonization by using an MDEA solution₂S content of about 4mg/m³、COS+CS₂About 79 mg/m in terms of sulfur³RSH about 29mg/m in terms of sulfur³、CO₂Is about 2.0%. After heat exchange and humidification, the gas enters a hydrolysis reactor at the temperature of 130 ℃ and the humidity of 120 ℃, and the gas at the outlet of the hydrolysis reactor enters a fine desulfurization unit after heat exchange and cooling to 40 ℃ and separation of free liquid. In the fine desulfurization unit, after being washed by sodium hydroxide alkali liquor with the mass fraction of 22 percent, the desulfurization product gas contains H₂S content<0.1mg/m³3.5 mg/m of total sulfur³、CO₂The content of (b) is 1.9%, and the dew point can be obtained by directly feeding the triethylene glycol into a triethylene glycol dehydration unit<-10 ℃ of product gas. The alkali liquor also contains 0.01 percent of sulfonated cobalt phthalocyanine and 0.1 percent of ammonium chloride by mass.

Example 4:

the pressure of the natural gas used in the test is 5.0MPa, and the volume fraction of the main component is H₂S 5.0%、CO₂ 6.0%、COS+CS₂50mg/m in terms of sulfur³RSH is 100mg/m in terms of sulfur³And the balance being methane. Raw material natural gas enters an alcohol amine desulphurization and decarbonization unit at 35-40 ℃, and H in semi-desulphurization and decarbonization gas is obtained after desulphurization and decarbonization by using an MDEA solution₂S content of about 4mg/m³、COS+CS₂About 40 mg/m in terms of sulfur³RSH is about 97mg/m in terms of sulfur³、CO₂Is about 2.0%. After heat exchange and humidification, the gas enters a hydrolysis reactor at the temperature of 130 ℃ and the humidity of 130 ℃, and the gas at the outlet of the hydrolysis reactor enters a fine desulfurization unit after heat exchange and cooling to 40 ℃ and separation of free liquid. In the fine desulfurization unit, after being washed by sodium hydroxide alkali liquor with the mass fraction of 22 percent, the desulfurization product gas contains H₂S content<0.1mg/m³Total sulfur 4.8 mg/m³、CO₂The content of (B) is 1.7%, triethylene glycol can be directly fed inA dehydration unit for obtaining dew point<-10 ℃ of product gas. The alkali liquor also contains 0.02 percent of sulfonated cobalt phthalocyanine, 0.2 percent of ammonium chloride and 0.01 percent of polybutanethiol cobalt by mass.

Example 5:

the pressure of the natural gas used in the test is 5.0MPa, and the volume fraction of the main component is H₂S 10.0%、CO₂ 6.0%、COS+CS₂150mg/m in terms of sulfur³RSH 50mg/m in terms of sulfur³And the balance being methane. Raw material natural gas enters an alcohol amine desulphurization and decarbonization unit at 35-40 ℃, and H in semi-desulphurization and decarbonization gas is obtained after desulphurization and decarbonization by using an MDEA solution₂S content about 15mg/m³、COS+CS₂About 119 mg/m in terms of sulfur³RSH is about 48mg/m in terms of sulfur³、CO₂Is about 1.8%. After heat exchange and humidification, the gas enters a hydrolysis reactor at the temperature of 130 ℃ and the humidity of 130 ℃, and the gas at the outlet of the hydrolysis reactor enters a fine desulfurization unit after heat exchange and cooling to 40 ℃ and separation of free liquid. In the fine desulfurization unit, after the fine desulfurization unit is washed by sodium hydroxide alkaline liquor with the mass fraction of 25%, H in the desulfurization product gas₂S content 0.5mg/m³Total sulfur 6.5 mg/m³、CO₂The content of (b) is 1.5%, and the dew point can be obtained by directly feeding into a triethylene glycol dehydration unit<-10 ℃ of product gas. The alkali liquor also contains 0.02 percent of sulfonated cobalt phthalocyanine, 0.2 percent of ammonium chloride and 0.01 percent of polybutanethiol cobalt by mass.

Example 6:

the pressure of the natural gas used in the test is 8.0MPa, and the volume fraction of the main component is H₂S 15.0%、CO₂ 10.0%、COS+CS₂150mg/m in terms of sulfur³RSH 50mg/m in terms of sulfur³And the balance being methane. Raw material natural gas enters an alcohol amine desulphurization and decarbonization unit at 35-40 ℃, and H in semi-desulphurization and decarbonization gas is obtained after desulphurization and decarbonization by using an MDEA solution₂S content about 20mg/m³、COS+CS₂About 122 mg/m in terms of sulfur³RSH is about 52mg/m in terms of sulfur³、CO₂Is about 1.8%. After heat exchange and humidification, the mixture enters a hydrolysis reactor at the temperature of 130 ℃ and the humidity of 130 ℃, and the gas at the outlet of the hydrolysis reactor is subjected to heat exchange and is cooled to 40 DEG CAnd the separated free liquid enters a fine desulfurization unit. In the fine desulfurization unit, after the fine desulfurization unit is washed by sodium hydroxide alkaline liquor with the mass fraction of 25%, H in the desulfurization product gas₂S content 1.2mg/m³Total sulfur 7.3 mg/m³、CO₂The content of (b) is 1.7%, and the dew point can be obtained by directly feeding the triethylene glycol into a triethylene glycol dehydration unit<-10 ℃ of product gas. The alkali liquor also contains 0.02 percent of sulfonated cobalt phthalocyanine, 0.2 percent of ammonium chloride and 0.01 percent of polybutanethiol cobalt by mass.

Example 7:

the pressure of the natural gas used in the test is 8.0MPa, and the volume fraction of the main component is H₂S 15.0%、CO₂ 10.0%、COS+CS₂100mg/m in terms of sulfur³RSH is 100mg/m in terms of sulfur³And the balance being methane. Raw material natural gas enters an alcohol amine desulphurization and decarbonization unit at 35-40 ℃, and H in semi-desulphurization and decarbonization gas is obtained after desulphurization and decarbonization by using an MDEA solution₂S content about 20mg/m³、COS+CS₂About 80 mg/m in terms of sulfur³RSH is about 103mg/m in terms of sulfur³、CO₂Is about 1.8%. After heat exchange and humidification, the gas enters a hydrolysis reactor at the temperature of 130 ℃ and the humidity of 130 ℃, and the gas at the outlet of the hydrolysis reactor enters a fine desulfurization unit after heat exchange and cooling to 40 ℃ and separation of free liquid. In the fine desulfurization unit, after the fine desulfurization unit is washed by sodium hydroxide alkaline liquor with the mass fraction of 25%, H in the desulfurization product gas₂S content 1.5mg/m³Total sulfur of 8.0 mg/m³、CO₂The content of (b) is 1.6%, and the dew point can be obtained by directly feeding the triethylene glycol into a triethylene glycol dehydration unit<-10 ℃ of product gas. The alkali liquor also contains 0.02 percent of sulfonated cobalt phthalocyanine, 0.2 percent of ammonium chloride and 0.01 percent of polybutanethiol cobalt by mass.

From the above examples, it can be seen that the technical scheme and process flow of the present invention have a wide range of sulfur-containing gas treatment, and can be adapted to the treatment of general sulfur content and high sulfur and high organic sulfur content. For the existing sulfur-containing device, the desulfurization and decarbonization device and the dehydration device do not need to be changed, and only COS/CS is added according to the situation₂And the hydrolysis and fine desulfurization working section can realize the quality upgrading of the natural gas.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.