CN102051244A - High-efficiency purification desulfurizer for high-acid oil and gas - Google Patents

Abstract

The invention belongs to the technical field of petroleum and natural gas purification, and relates to a desulfurizer for efficiently purifying and removing acidic components from highly acidic petroleum and natural gas. Containing 10-85% (wt) of alcohol amine compound, 15-75% (wt) of oxygen-containing and/or nitrogen-containing heterocyclic compound A, and 0.1-30% (wt) of oxygen-containing and/or nitrogen-containing heterocyclic compound B , 0.1-30% (wt) sulfur-containing heterocyclic compound, and 10-80% (wt) water. By adopting the desulfurizer of the present invention, organic sulfur, H ₂ S and CO ₂ in highly acidic petroleum and natural gas can be respectively reduced from about 1000 mg/Nm ³ , about 15% (mol) and about 9% (mol) to below 20 mg/Nm ³ , below 5mg/Nm ³ and below 0.1% (mol), the organic sulfur removal rate can reach up to 98%. The pressure of raw material high-acid oil and gas can be between 0.1MPa and 8.5MPa. Compared with ordinary alcohol amine solvents, the desulfurizer of the present invention has significant advantages such as high desulfurization rate, good stability, low regeneration energy consumption, less running loss, and less foaming. It is suitable for oil and gas with high sulfur content, especially high organic sulfur content. The purification has obvious effect.

Description

High-efficiency purification and desulfurization agent for highly acidic oil and gas

Technical field: the invention belongs to the technical field of petroleum and natural gas purification, and specifically relates to a method for efficiently removing acidic components from highly acidic petroleum and natural gas, especially from sour petroleum and natural gas containing high concentrations of sulfides such as COS, H ₂ S and mercaptans. Partial desulfurizer.

Background technology: Natural gas produced from gas fields usually contains various acidic components, and these acidic components mainly include H ₂ S, sulfides such as COS and RSH, and CO ₂ . The types and contents of acidic components in the natural gas of various gas fields vary greatly. The content of acidic components in the natural gas of the same gas field is also different at different stages of exploitation. Usually, the content of organic sulfur in natural gas will vary to varying degrees with the prolongation of the development time of the gas field. Increase.

High concentration of CO ₂ will reduce the calorific value of natural gas; the existence of H ₂ S will not only cause corrosion to the pipeline but also seriously endanger the health of users; and COS is the main component of organic sulfur contained in natural gas, if it is not removed On the one hand, it will poison the catalyst of the downstream chemical process using natural gas as raw material; on the other hand, the untreated COS discharged into the atmosphere can form SO ₂ , which promotes photochemical reactions and brings serious environmental problems. At the same time, these sulfur compounds have an unbearable odor even at extremely low concentration levels. Therefore, the acidic components, especially sulfides, must be removed to a specific value before the natural gas is transported into pipelines. For example, GB 17820-1999 stipulates that H ₂ S ≤ 20 mg/Nm ³ , total sulfur ≤ 200 mg/Nm ³ , and CO ₂ ≤ 3% (mol) in civil secondary natural gas in China.

The alkanolamine method is a common method for removing these acidic components. Commonly used alcoholamines include monoethanolamine (MEA), diethanolamine (DEA), methylmonoethanolamine (MMEA), diethylethanolamine (DEEA), triethanolamine (TEA), diisopropanolamine (DIPA), diglycolamine (DGA) and N-methyldiethanolamine (MDEA). Usually these alcohol amines can remove most of H ₂ S and CO ₂ in natural gas, but it is usually difficult to effectively remove organic sulfur by using only alcohol amines. For example, the removal rates of MEA and DEA to methyl mercaptan, ethanethiol and propylene mercaptan are about 45%-50%, 20-25% and 0-10%, respectively. In order to effectively remove high-concentration COS in natural gas, the known process often adopts a three-stage process, that is, two absorption towers plus a COS hydrolysis reactor. The sour natural gas first removes most of the H ₂ S in the first absorption tower and CO ₂ , enter the hydrolysis reactor to hydrolyze and convert COS after heating up, and then go through the second absorption tower to further remove residual CO ₂ and H ₂ S generated by the hydrolysis reaction. Since the whole process has experienced the heating and cooling process of the raw material gas, the energy consumption is increased and the process flow is complicated. Moreover, this process cannot guarantee the effective removal of high-concentration mercaptan compounds.

If an absorbent with a good removal effect on high-concentration COS and organic sulfides such as mercaptans is used to realize the one-step removal of each acidic component, the process can be simplified and energy consumption can be reduced.

Most workers improve the removal effect of organic sulfur by adding an appropriate amount of auxiliary solvent to the MDEA-based solution, in order to further reduce the total sulfur content in purified oil and gas.

US 4808765 adopts the process of contacting the gas with MDEA, DIPA and NaOH respectively to remove H ₂ S, COS and mercaptan in the gas flow, and the process and equipment are extremely complicated.

US 4462968 achieves the purpose of removing mercaptans by adding H ₂ O ₂ to the treatment liquid, but it is only applicable to feed gas whose mercaptan concentration is lower than 50mg/Nm ³ .

The patent US 4336233 of BASF Company describes the removal of H ₂ S, CO ₂ and COS in the mixed gas by using MDEA as the main solvent and adding 0.05-0.8 mol/L piperazine as the activator.

US 6740230B1 and 6337059B1 also use piperazine-activated MDEA as a solvent to remove H ₂ S, CO ₂ and low-concentration organic sulfides in acid gases.

Both CN 1421264A and 1887406A use MDEA and hindered amine as the main solvent, and add an appropriate amount of co-solvent and catalyst to remove _H2S and most of the organic sulfur in the gas mixture.

None of the above methods involves the purification effect of oil and gas with high content of organic sulfur and high content of H ₂ S at the same time. When the content of H ₂ S in petroleum and natural gas is up to about 15% (mol), and the content of organic sulfur exceeds 600 mg/Nm ³ or even reaches 2000 mg/Nm ³ , it is difficult to purify the content of acidic components in petroleum and natural gas by using the above solvents. Especially the total sulfur content meets the standard requirements.

Summary of the invention: The object of the present invention is to propose a highly efficient purifying desulfurizer (Unitedly developed desulfur solvent, UDS for short) to remove high-concentration _{H 2 S} At the same time as _CO2 , high-concentration COS and organic sulfides such as mercaptans are efficiently removed, and each acidic component is removed to the required index value in one step.

Compared with other solvents, the desulfurizer of the present invention shows more outstanding advantages when the UDS desulfurizer is used to treat oil and gas with high sulfide content, especially oil and gas with high organic sulfide content. It provides a guarantee for the reliable production of high-acid natural gas fields, and at the same time simplifies the removal process and improves the economical efficiency of the process.

The main technical scheme of the present invention is: UDS desulfurizer is composed of alcohol amine compound of 10-85% (wt) by weight, 15-75% (wt) of oxygen-containing and/or nitrogen-containing heterocyclic compound A, 0.1-30% (wt) oxygen- and/or nitrogen-containing heterocyclic compound B, 0.1-30% (wt) sulfur-containing heterocyclic compound, and 10-80% (wt) water.

Generally, the alcohol amine compound in the present invention is a primary amine compound, a secondary amine compound, a tertiary amine compound or a mixture of two or more thereof; the suitable dosage of the alcohol amine compound is 10-70%.

The compound A is a monocyclic, bicyclic or tricyclic compound, preferably a six-membered monoepoxy azacyclic compound; the dosage of the compound A is 25-65%.

The compound B is an oxygen- and/or nitrogen-containing heterocyclic compound, preferably a six-membered nitrogen-containing unsaturated heterocyclic compound; the suitable dosage of the compound B is 0.1-15%.

The sulfur-containing heterocyclic compound is a five-membered or six-membered sulfur-containing heterocyclic compound; the suitable dosage of the sulfur-containing heterocyclic compound is 0.1-15%.

The highly acidic petroleum and natural gas may be acidic petroleum and natural gas containing ~20% (mol) H ₂ S, ~2000 mg/ ^Nm organic sulfur and/or ~20% (mol) CO ₂ ; the organic sulfur is carbonyl Sulfur, methyl mercaptan, ethanethiol, propylene mercaptan, and other mercaptan or thioether compounds or a mixture of several; the pressure of high acid oil and gas can be 0.1MPa to 8.5MPa.

UDS desulfurizer can replace a single alcohol amine compound with a mixture of two or more alcohol amine compounds to achieve more effective removal of harmful components in natural gas (especially H ₂ S and CO ₂ ) , while expanding the adaptability to raw materials.

By adding oxygen-containing and/or nitrogen-containing heterocyclic compound A, UDS desulfurizer can significantly increase the adaptability of the solvent to various sulfides in the raw gas, improve the total sulfur removal rate, and significantly reduce the total sulfur content in the purified tail gas.

Adding oxygen-containing and/or nitrogen-containing heterocyclic compound B to the UDS desulfurizer can significantly increase the solvent's absorption activity of sulfide and increase the desulfurization rate.

Due to the addition of sulfur-containing heterocyclic compounds, the UDS desulfurizer has a stronger binding ability to sulfide, and it can show superior desulfurization performance when used as a purification solvent for oil and gas with high sulfide content.

Compared with ordinary alcohol amine solvents, UDS desulfurizer has the advantages of high desulfurization rate, good thermal stability, low regeneration energy consumption, strong degradation resistance, low running loss, less foaming, and low corrosion. For high sulfur content, Especially the purification of oil and gas with high organic sulfur content has obvious advantages.

BRIEF DESCRIPTION OF THE DRAWINGS: Accompanying drawing 1 is a block flow diagram of an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: The present invention will be described in detail below in conjunction with the embodiments and accompanying drawings.

When the present embodiment uses UDS desulfurizer to purify highly acidic oil and gas, it can be implemented according to the mode of accompanying drawing 1:

High-acid oil and natural gas are in reverse contact with the absorption liquid in the absorption tower, the purified gas after removing the acidic components is discharged from the top of the tower, and the rich liquid that has absorbed the acidic components comes out from the bottom of the tower and enters the rich liquid flash tank for flash evaporation Dissolved hydrocarbons are discharged, and after heat exchange between the flash-evaporated rich liquid and the regenerated lean liquid, it enters the regeneration tower for desorption and regeneration. The desorbed acid gas is discharged from the top of the regeneration tower, and the regenerated lean liquid is discharged from the bottom of the tower, and returned to the absorption tower for recycling after heat exchange with the rich liquid and cooling. Compared with the process with COS hydrolysis reactor, the process is obviously simpler and more economical.

Implementation example one

High acid oil and natural gas contains organic sulfur 999.1mg/Nm ³ , H ₂ S 15.11% (mol), CO ₂ 8.96% (mol). Carry out the absorption experiment according to the flow process shown in Fig. 1, the formula that UDS desulfurizer adopts is: the monoethanolamine of 26% (wt) six-membered epoxy azacyclic compound, 3% (wt) monoethanolamine, 3% (wt) the Diethanolamine, 2% (wt) six-membered nitrogen-containing unsaturated heterocyclic compound, 2% (wt) five-membered sulfur-containing heterocyclic compound, 59% (wt) water, and the rest is N-methyldiethanolamine. The absorption temperature is 16°C, the absorption pressure is 2×10 ⁵ Pa, the feed gas flow rate is 55.3L/h, and the absorption liquid circulation rate is 0.42L/h. Organic sulfur in purified gas after absorption treatment is 16.2mg/Nm ³ , H ₂ S 4mg/Nm ³ , CO ₂ <0.1% (mol). The removal rate of organic sulfur is 98.77%.

Implementation example two

High acid oil and natural gas contains organic sulfur 999.1mg/Nm ³ , H ₂ S 15.11% (mol), CO ₂ 8.96% (mol). The absorption experiment is carried out according to the flow process shown in Figure 1, and the formula that the UDS desulfurizer adopts is: 42% (wt) of six-membered epoxy nitrogen heterocyclic compound, 5% (wt) of monoethanolamine, 5% (wt) of Diethanolamine, 3% (wt) six-membered nitrogen-containing unsaturated heterocyclic compound, 3% (wt) five-membered sulfur-containing heterocyclic compound, 35% (wt) water, and the rest is N-methyldiethanolamine. The absorption temperature is 18°C, the absorption pressure is 2×10 ⁵ Pa, the feed gas flow rate is 20.9L/h, and the absorption liquid circulation rate is 0.54L/h. Organic sulfur in purified gas after absorption treatment is 19.6mg/Nm ³ , H ₂ S 1.5mg/Nm ³ , CO ₂ <0.1% (mol). The removal rate of organic sulfur is 98.51%.

Implementation example three

High acid oil and natural gas contains organic sulfur 1110mg/Nm ³ , H ₂ S 16.8% (mol), CO ₂ 8.8% (mol). The absorption experiment is carried out according to the flow process shown in Figure 1, and the formula that UDS desulfurizer adopts is: 32% (wt) of six-membered epoxy nitrogen heterocyclic compound, 4% (wt) of monoethanolamine, 4% (wt) of Diethanolamine, 2% (wt) six-membered nitrogen-containing unsaturated heterocyclic compound, 3% (wt) five-membered sulfur-containing heterocyclic compound, 50% (wt) water, and the rest is N-methyldiethanolamine. The absorption temperature is 40°C, the absorption pressure is 15×10 ⁵ Pa, the feed gas flow rate is 135L/h, and the absorption liquid circulation rate is 0.8L/h. Organic sulfur in purified gas after absorption treatment is 81.6mg/Nm ³ , H ₂ S<0.5mg/Nm ³ , CO ₂ <0.1% (mol). The removal rate of organic sulfur is 94.49%.

Implementation example four

High acid oil and natural gas contains organic sulfur 1258.6mg/Nm ³ , CO ₂ 8.3% (mol). The absorption experiment is carried out according to the flow process shown in Figure 1, and the formula that UDS desulfurizer adopts is: 32% (wt) of six-membered epoxy nitrogen heterocyclic compound, 4% (wt) of monoethanolamine, 4% (wt) of Diethanolamine, 2% (wt) six-membered nitrogen-containing unsaturated heterocyclic compound, 3% (wt) five-membered sulfur-containing heterocyclic compound, 50% (wt) water, and the rest is N-methyldiethanolamine. The absorption temperature is 33°C, the absorption pressure is 10.5×10 ⁵ Pa, the feed gas flow rate is 100L/h, and the absorption liquid circulation rate is 0.8L/h. Organic sulfur in purified gas after absorption treatment is 70.8 mg/Nm ³ , CO ₂ <0.1% (mol). The removal rate of organic sulfur is 94.84%.

Implementation example five

High acid oil and natural gas contains organic sulfur 1100mg/Nm ³ , H ₂ S 17.2% (mol), CO ₂ 8.5% (mol). The absorption experiment is carried out according to the flow process shown in Figure 1, and the formula that UDS desulfurizer adopts is: 32% (wt) of six-membered epoxy nitrogen heterocyclic compound, 4% (wt) of monoethanolamine, 4% (wt) of Diethanolamine, 2% (wt) six-membered nitrogen-containing unsaturated heterocyclic compound, 3% (wt) five-membered sulfur-containing heterocyclic compound, 50% (wt) water, and the rest is N-methyldiethanolamine. The absorption temperature is 40°C, the absorption pressure is 83×10 ⁵ Pa, the feed gas flow rate is 400L/h, and the absorption liquid circulation rate is 5L/h. After absorption treatment, organic sulfur in the purified gas is 38.1mg/Nm ³ , H ₂ S 46.6mg/Nm ³ , CO ₂ <0.2% (mol). The removal rate of organic sulfur is 97.43%.

Implementation example six

High acid oil and natural gas contains organic sulfur 999.1mg/Nm ³ , H ₂ S 15.11% (mol), CO ₂ 8.96% (mol). The absorption experiment is carried out according to the flow process shown in Figure 1, and the formula that UDS desulfurizer adopts is: 22% (wt) of six-membered monoepoxide azacyclic compound, 4% (wt) of monoethanolamine, 4% (wt) of Diethanolamine, 2% (wt) six-membered nitrogen-containing unsaturated heterocyclic compound, 2% (wt) five-membered sulfur-containing heterocyclic compound, 64% (wt) water, and the rest is N-methyldiethanolamine. The absorption temperature is 19°C, the absorption pressure is 2×10 ⁵ Pa, the feed gas flow rate is 52.2L/h, and the absorption liquid circulation rate is 0.45L/h. Organic sulfur in purified gas after absorption treatment is 355.5mg/Nm ³ , H ₂ S 52mg/Nm ³ , CO ₂ <0.1% (mol). The removal rate of organic sulfur is 72.96%.

Comparative example one

High acid oil and natural gas contains organic sulfur 999.1mg/Nm ³ , H ₂ S 15.11% (mol), CO ₂ 8.96% (mol). The absorption experiment was carried out according to the process shown in Figure 1. The desulfurization agent was 65% (wt) MDEA, the absorption temperature was 17°C, the absorption pressure was 2×10 ⁵ Pa, the feed gas flow rate was 55.3 L/h, and the absorption liquid circulation volume was 0.42 L/h. h. The purified gas after absorption treatment contains 603.3 mg/Nm ³ organic sulfur, 145 mg/Nm ³ H ₂ S and 0.65% (mol) CO ₂ . The removal rate of organic sulfur is 54.11%.

Comparative example two

High acid oil and natural gas contains organic sulfur 1110mg/Nm ³ , H ₂ S 15.3% (mol), CO ₂ 8.4% (mol). The absorption experiment was carried out according to the process shown in Figure 1. The desulfurizer was 50% (wt) MDEA, the absorption temperature was 40°C, the absorption pressure was 15×10 ⁵ Pa, the raw gas flow rate was 135L/h, and the absorption liquid circulation volume was 0.8L/h . The purified gas after absorption treatment contains 432.8 mg/Nm ³ organic sulfur, H ₂ S<0.5 mg/Nm ³ , and 0.3% (mol) CO ₂ . The removal rate of organic sulfur is 69.91%.

Comparative example three

High acid oil and natural gas contains organic sulfur 1100mg/Nm ³ , H ₂ S 16.3% (mol), CO ₂ 8.7% (mol). The absorption experiment was carried out according to the process flow shown in Figure 1, and the desulfurizer used 50% (wt) MDEA. The absorption temperature is 40°C, the absorption pressure is 83×10 ⁵ Pa, the feed gas flow rate is 500L/h, and the absorption liquid circulation rate is 5L/h. After absorption treatment, the organic sulfur in the purified gas is 536.2mg/Nm ³ , H ₂ S 116.1mg/Nm ³ , and CO ₂ 0.6% (mol). The removal rate of organic sulfur is 63.18%.

Claims (14)

1. High-efficiency purification and desulfurization agent for highly acidic petroleum and natural gas, which is an absorption solvent for efficiently purifying and removing acidic components from highly acidic petroleum and natural gas, characterized in that the desulfurizing agent is composed of alcohol amine with a weight percentage of 10 to 85%. compound, 15-75% of oxygen- and/or nitrogen-containing heterocyclic compound A, 0.1-30% of oxygen- and/or nitrogen-containing heterocyclic compound B, 0.1-30% of sulfur-containing heterocyclic compound and 10-80% of water composition. 2. The desulfurizing agent according to claim 1, characterized in that the alcohol amine compound is a primary amine compound, a secondary amine compound, a tertiary amine compound or a mixture of two or more of them. 3. The desulfurizing agent according to claim 1 or 2, characterized in that the amount of alcohol amine compound is 10-70%. 4. The desulfurizing agent according to claim 1, characterized in that the compound A is a monocyclic, bicyclic or tricyclic compound. 5. The desulfurizing agent according to claim 4, characterized in that the compound A is a six-membered monoepoxide nitrogen heterocyclic compound. 6. The desulfurizing agent according to claim 1, characterized in that the amount of the compound A is 25-65%. 7. The desulfurizer according to claim 1, characterized in that the compound B is an oxygen- and/or nitrogen-containing heterocyclic compound, but the compound B is different from the compound A described in claims 1 or 4-6. 8. The desulfurizing agent according to claim 7, characterized in that the compound B is a six-membered nitrogen-containing unsaturated heterocyclic compound. 9. The desulfurizing agent according to claim 1, characterized in that the compound B is used in an amount of 0.1-15%. 10. The desulfurizing agent according to claim 1, characterized in that the sulfur-containing heterocyclic compound is a five-membered or six-membered sulfur-containing heterocyclic compound. 11. The desulfurizing agent according to claim 1, characterized in that the amount of the sulfur-containing heterocyclic compound is 0.1-15%. 12. The desulfurizer according to claim 1, characterized in that the highly acidic petroleum and natural gas contains ~20% (mol) H ₂ S, ~2000 mg/Nm ³ organic sulfur and/or ~20% (mol) CO ₂ for sour oil and gas. 13. The desulfurizing agent according to claim 12, characterized in that the organic sulfur is one or more of carbonyl sulfide, methyl mercaptan, ethanethiol, propanethiol and other mercaptan or thioether compounds mixture. 14. The desulfurizer according to claim 1 or 12, characterized in that the pressure of the highly acidic oil and gas is between 0.1MPa and 8.5MPa.

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