The method of preparing sulfur-containing gas to the fractionation

 

(57) Abstract:

The invention relates to the processing of sulfur-containing gas and can be used at gas processing plants and installations of complex processing gases. The method of preparing sulfur-containing gas to the fractionation involves the removal of acid impurities and mercaptans by means of absorption solution methyldiethanolamine, drying, subsequent degassing of the adsorbent and its regeneration at a temperature of 120-140oWith the submission of sour gas from phase regeneration for processing into elemental sulfur by the Claus reaction, while cleaning and drying of sulfur-containing gas takes place simultaneously in the absorption process integrated absorbent, representing a solution of methyldiethanolamine ethylene glycol and having a composition, wt.%: methyldiethanolamine 40-60, ethylene glycol 40-60. The absorption can be carried out at a temperature of 30-40oAnd degassing after throttling by blowing inert or partially soluble in the absorbent gas at a temperature of absorption or by heating to 60-70oC. the Proposed method allows to significantly simplify the process, to increase the depth and selectivity purification and recycle of sulfur-containing gases with polysensitized gas, in particular selective adsorption of natural gas, gas processing plants and facilities for the complex processing of gases for commercial gas used as fuel and raw materials for the petrochemical and sour gas recovery, used as raw material for production of elemental sulfur for plants Claus.

There is a method of preparation of gas feed to the fractionation, including cleaning and drying using a non-aqueous composite sinks, where as alkanolamine used monoethanolamine, diethanolamine, diisopropanolamine, and as an organic solvent - sulfolane, methanol, benzyl alcohol, N-organic, tetrahydrofuranyl alcohol /Cleaning of process gases. Edited by Semenova So on, Leites, I. L., M., Chemistry, 1977, S. 236-241/.

The known method allows you to clean any sulfur-containing raw material gas, however, has no selectivity for hydrogen sulfide in the presence of carbon dioxide and leads to the absorption of a significant amount of hydrocarbons from the gas, which complicates subsequent processing of sour gas in the Claus process.

Closest to the proposed method on the basis of the Yu, includes cleaning of acidic components from natural gas: hydrogen sulfide, carbon dioxide, therookie carbon, carbon disulphide and mercaptans - absorption 35-50 wt.% aqueous solution of methyldiethanolamine with purification from mercaptans by adsorption on zeolite, drying the purified commodity gas glycols with degassing and absorbent regeneration at 125oWith obtaining sour gas, which is sent for recycling to produce elementary sulfur by the Claus reaction. The hydrogen sulfide content in the purified gas to 20 mg/m3and mercaptans, after purification on zeolites, up to 36 mg/m3(mercaptan sulfur) /Struchkov C. M., Afanasiev, A. I., Vysheslavtsev Y. F., Stepanyuk C. A., Murin Century. And., Nastika Century. And. , Borodin, B. P., Latuk Century. And. Scientific - technical achievements in the field of desulfurization of gases. - M.: Negatron, 1988, 30 s/.

However, this method leads to high water cut as acidic (up to 10 wt.%) and clean gas (up to 2.5 g/m3) why for processing the latter introduces an additional step of drying mono - and diethylenglycol. In addition, in the case of purification of gases with a high content of carbon dioxide, for example sulfur-containing gas of Karachaganak field, there is no need selectives the receiving of carbon dioxide and hydrogen sulfide, not relevant requirements of the Claus process (hydrogen sulphide content for the Claus process should be not less than 50 wt.%, and the content of carbon dioxide is not more than 40 wt.%). This leads to the need for pre-mixing gas of Karachaganak field with other sulfur-containing gas, characterized by a significantly lower proportion of carbon dioxide compared with hydrogen sulfide, for example Orenburg gas field, i.e. the introduction of an additional stage. To the disadvantage of the prototype can be attributed to the low degree of extraction (10%) mercaptans aqueous solutions of methyldiethanolamine that requires special stage purification of marketable gas on zeolite /in. A. Nikolaev, N. In. Busygin, I., Busygin. The basic processes of physical and chemical processing of natural gas. M.: Nedra, 1998, S. 25/.

The present invention is the simplification of the process by providing simultaneous removal of acid impurities, including mercaptans, and drying gas reaching required for the Claus process selectivity in the case of purification of sulfur-containing gases with a high content of carbon dioxide, for example Karachaganak gas field.

oWith the submission of sour gas from phase regeneration for processing into elemental sulfur by the Claus reaction, which according to the invention the cleaning and drying of sulfur-containing gas takes place simultaneously in the absorption process integrated absorbent, representing a solution of methyldiethanolamine ethylene glycol and having a composition (wt.%): methyldiethanolamine 40-60, ethylene glycol 40-60.

And that

the absorption is carried out at a temperature of 30-40oWITH,

degassing of the absorbent perform throttling followed by purging with an inert gas or poorly soluble in the absorbent gas at a temperature of absorption or by heating to a temperature of 60-70oC.

The method is as follows: high-pressure natural gas (pressure 4-5 MPa) or low-pressure process gas (pressure of 0.5-3.0 MPa) after mechanical separation of liquid hydrocarbons and solids is sent to the absorber is equipped with a thermocouple to record the temperature at the stages of absorption, decontamination and regeneration of the absorbent. To the output gas lines carry out sampling for chromatographic OLE: 40-60 wt.%. methyldiethanolamine, 40-60 wt.% of ethylene glycol.

The use of integrated absorbent on the basis of a mixture of ethylene glycol and methyldiethanolamine leads to unexpected effect: the emergence of synergies related to the removal of acid components and mercaptans while reducing the solubility in the hydrocarbon absorbent gas components, both due to the high polarity and high basicity of the proposed absorbent.

The absorption is carried out at a temperature of 25-45oC, preferably at a temperature of 30-40oC. the Stage of absorption is carried out before the start of the breakthrough of hydrogen sulfide in the purified gas and iodometrically determine the content of hydrogen sulfide and mercaptans. The residual hydrogen sulphide content in the purified gas is not more than 6 mg/m3that meets the requirements of OST 51.40-93, and the residual content of mercaptans, no more than 36 mg/m3(OST 51.40-83) when the degree of extraction of the mercaptans is not less than 92%.

Saturated absorbent Tegaserod at a temperature absorption overlap of the intake valve and the gradual pressure drop in the absorber to a pressure close to atmospheric. Gases degassing analyze chromatographic content key is an additional degassing passing through the absorber inert gas (nitrogen, helium or gas, soluble in the absorbent, for example methane. In the case of low-pressure gas additional degassing is performed by heating the adsorbent to a temperature of 60-70oC. Discharge valve overlap and to begin the process of regeneration temperature raise up to 120-140oC. the Obtained acidic gas regeneration analyze chromatographic.

Below are examples of the implementation of the method.

Example 1.

The process is carried out at pilot plant. The absorber is designed for 400 g of the absorbent fill an integrated absorbent (AK), representing a solution of methyldiethanolamine in ethylene glycol - 50 wt.% methyldiethanolamine and 50 wt.% of ethylene glycol. At a temperature of 30oThrough the absorbent miss raw gas of Karachaganak field (gas pressure 5 MPa), the last stage mechanical separation of liquid hydrocarbons and solids. The composition of the gas to be cleaned, are given in table. 1.

The absorption leads to early breakthrough of hydrogen sulfide in the purified gas. Get cleaned commodity gas with residual hydrogen sulphide content of not more than 6 mg/m3and mercaptans, no more than 36 mg/m3. Degassing of the absorbent are so, Kant regenerate at 120oC.

Example 2.

The method is carried out analogously to example 1, but using absorbent having a composition: 60 wt.% methyldiethanolamine, 40 wt.% of ethylene glycol. Temperature absorption 40oC. the temperature of the degassing 40oC. the temperature of the regeneration 140oC. Get cleaned commodity gas with residual hydrogen sulphide content of not more than 6 mg/m3and mercaptans, no more than 36 mg/m3.

The composition of the acid gas obtained by the method of examples 1 and 2, are presented in table. 2.

Comparative data on the composition of the acid gas obtained by the purification Karachaganakskogo gas under the proposed method (AK) and for water prototype (VP) /Struchkov C. M., Afanasiev, A. I., Vysheslavtsev Y. F., Stepanyuk C. A. , Murin Century. And., Nastika Century. And., Borodin, B. P., Latuk Century. And. Scientific - technical achievements in the field of desulfurization of gases. - M.: Negatron, 1988, 30 s/ are given in table. 3.

As can be seen from the presented data (table. 2, 3), received the sour gas is in fact satisfies the conditions of installation Claus not only on the ratio of N2S-CO2but the content of the hydrocarbon components (less than 8 vol%).

Thus, the proposed is inromania by combining stages of cleaning and drying;

recycle sulfur-containing gases with a high content of carbon dioxide, for example, the Karachaganak field;

to carry out deep cleaning commercial gas from mercaptans, eliminating an additional unit of adsorption purification of gases in zeolites.

1. The method of preparing sulfur-containing gas by fractionation, including the removal of acid impurities and mercaptans by means of absorption solution methyldiethanolamine, drying, subsequent degassing of the adsorbent and its regeneration at a temperature of 120-140oWith the submission of sour gas from phase regeneration for processing into elemental sulfur by the Claus reaction, characterized in that the cleaning and drying of sulfur-containing gas takes place simultaneously in the absorption process integrated absorbent, representing a solution of methyldiethanolamine ethylene glycol and having a composition, wt. %:

Methyldiethanolamine - 40-60

The glycol - 40-60

2. The method according to p. 1, wherein the absorption is carried out at a temperature of 30-40oC.

3. The method according to p. 1, characterized in that the degassing of the absorbent perform throttling followed by purging with an inert gas or a gas soluble in the absorbent at a temperature

 

Same patents:

The invention relates to the dehydration of natural gas

The invention relates to a method for processing natural gas to remove water and/or extraction of impurities higher hydrocarbons

The invention relates to oil and gas industry, in particular to methods of gas purification from sulfur compounds

The invention relates to a method of purification of natural gas and bring it to compliance with requirements, marketable gas, which consists in the fact that the gas has a dew point between 0 and -18oC and the content of H2below 4 million
The invention relates to solid compositions for storage and transportation of hydrocarbon gases, namely clathrate compounds include natural gas on the basis of the fluorinated graphite of the total composition CxFClyzCnH2n+2where x=1.8 to 2.5, y=0,08-0,09, z=0,12-0,22, CnH2n+2methane, ethane, propane and butane

The invention relates to the petrochemical and gas industry, and more specifically to a method of cleaning gases from sulfur-containing compounds

The invention relates to a method of removing sulfur compounds from flue gas sulfur recovery method Claus

The invention relates to methods for fine purification of gases from sulfur compounds and may find use in the purification of natural gas

The invention relates to a method for removing elemental sulfur present in the gas in the form of vapor and/or entrained particles, in which the treated gas is cooled to a temperature between the point of condensation of water vapor and 120oC

The invention relates to a method of selective cleaning of gases from inorganic and/or organic sulfur compounds, such as hydrogen sulfide, carbondisulfide, carbon disulfide, mercaptans, etc

The invention relates to processes for the production of sulfur from acid gases and can be used in oil, gas, petrochemical and other industries

The invention relates to a method of removing nitrogen from natural gas

The invention relates to a power system and can be used in boilers, industrial furnaces, heat generators and heat engines, burning of gas, liquid and solid fossil fuels

The invention relates to gas industry and is intended for use in installations of commercial preparation of natural gas to the main transport method of absorption and drying, in particular, the invention relates to a method of cleaning solution of glycol natural gas dehydrator

The invention relates to the field of absorption and purification of hydrocarbon gases from sulfur compounds liquid organic absorbents and may find application in oil and gas industries for purification of natural gas from hydrogen sulfide, and hydrogen sulfide and mercaptans
Up!