Comprehensive utilization of dry gas
Thread Content
Which expert knows the mature technologies for the comprehensive utilization and value addition of dry gas (methane, ethane)? Looking forward to your guidance!
Hydrogen production: high price of hydrogen, mature technology for the facilities, low investment requirements, and quick returns
At present, the Institute of Rock Mechanics is working on a project to produce methanol gasoline from dry gas
The technology for producing ethylbenzene from dry gas is efficient and fairly mature.
Ethylbenzene can be produced from dry gas, styrene can be obtained from ethylbenzene, and styrene can then be further processed downstream. . . . . . .
The more mature method is hydrogen production via dry gas adsorption; hydrogen is expensive, thus it has a high added value. There are also processes for producing methanol; it depends on the scale and whether it is worth investing in.
May I ask the experts here: can methane and ethane also be used to produce ethylbenzene? What other uses are there besides those mentioned above?
The production of ethylbenzene from dry gas involves using the ethylene present in it to carry out a hydrocarbonation reaction with benzene, thereby producing ethylbenzene. Therefore, the presence of ethylene in dry gas is a necessary condition for manufacturing ethylbenzene.
Comprehensive Utilization Technologies of Refinery Gas Qiao Yingbin Abstract: This paper briefly describes the comprehensive utilization technologies for resources such as hydrogen, ethylene, propylene, and butylene in China’s refinery gas. The utilization of dry gas includes technologies such as membrane separation and purification of catalytic cracking dry gas to produce hydrogen, the use of coking dry gas as a raw material for hydrogen production, and the production of ethylbenzene from catalytic cracking dry gas ； Propylene utilization technologies include technologies for producing polypropylene, technologies for producing acrylonitrile, and technologies for producing isopropyl alcohol ； C4 utilization technologies include MTBE production technology, butadiene production technology, isobutylene production technology, and methylethyl ketone production technology. Producing high-value-added products from refinery gas will be an important technical issue that needs to be addressed urgently in the future. Keywords: Refinery gas; Comprehensive utilization; Petrochemical industry; Review
TECHNOLOGIES FOR COMPREHENSIVE UTILIZATION OF REFINERY GAS
Qiao Yingbin (SINOPEC Technological Development Center, Beijing 100029)
Abstract: The domestically developed technologies for utilizing hydrogen, ethylene, propylene, and butylenes derived from refinery gas are reviewed. These technologies include: the separation of hydrogen from FCC dry gas using membranes; hydrotreating coker gas to produce feedstock for steam reforming; the alkylation of ethylbenzene from FCC dry gas without prior treatment; the production of polypropylene, acrylonitrile, and isopropyl alcohol from propylene; and the manufacture of MTBE, butadiene, isobutylene, and methyl ethyl ketone from butylenes. There is still an urgent need for further comprehensive utilization of refinery gas to produce products with high added value.
Key Words: Refinery gas; Comprehensive utilization; Petrochemical industry; Review
1. Introduction
China’s refineries have a crude oil processing capacity of approximately 200 million tons per year. Due to the high proportion of heavy fractions in crude oil, secondary processing units play a significant role in these refineries. For example, the processing capacity of catalytic cracking (FCC) units is around 60 million tons per year; there are many units for the secondary processing of crude oil, and there is also an abundant supply of refinery gas. In particular, the DCC, MGG, and MIO technologies developed in China in recent years [1] have enabled the production of ethylene, propylene, and butylene to increase exponentially (or even several times), providing ample raw materials for the comprehensive utilization of refinery gas. Through years of research and development, the technologies for further processing refinery gas to produce petrochemical products have seen some of them put into industrial use, with their technical levels reaching international advanced standards. This article provides a brief introduction to the comprehensive utilization technologies for refinery gas that have been successfully developed in China. 2 Utilization technologies of dry gas: The dry gas in refineries mainly refers to FCC dry gas and delayed coking dry gas. The main components of FCC dry gas are hydrogen (accounting for 25%–40%) and ethylene (accounting for 10%–20%), while the main components of delayed coking dry gas are methane and ethane. This article mainly introduces the technologies of producing hydrogen through FCC dry gas separation and purification, producing ethylbenzene from FCC dry gas and ethylene, and using coking dry gas as a raw material for hydrogen production. 2.1 Technology for hydrogen production through catalytic cracking dry gas separation and purification［2］ The Dalian Institute of Chemical Physics, Chinese Academy of Sciences, in collaboration with Shijiazhuang Refinery, successfully developed a technology for separating and purifying hydrogen from FCC dry gas using mesoporous fiber membranes. As tested by Shijiazhuang Refinery, under conditions of a temperature of 45 ℃, a pressure of 6.1 MPa, and an osmotic pressure of 0.2 MPa, the hydrogen recovery rate using domestic separation membranes for FCC dry gas was 89.4%. This result indicates that it is feasible to use this technology for hydrogen purification via FCC dry gas separation. For a large FCC unit, the value of hydrogen recovered in one year amounts to tens of millions of yuan, resulting in significant economic benefits. The composition and quantity of dry gas and the recovered hydrogen are shown in Tables 1 and 2. The FCC unit at Shijiazhuang Refinery uses atmospheric residue as feedstock; no passivator is added during operation to produce hydrogen from the dry gas, resulting in a high hydrogen content in the dry gas. Table 1 Composition and quantity of dry gas
Component Composition/% Absolute amount/t.a-1
Hydrogen 46.49 8 460
Nitrogen 5.64 14 249
Methane 19.99 28 943
Ethylene 6.11 15 462
Ethane 12.40 33 648
C3–C5 9.37 42 194
Table 2 Composition and quantity of the recovered hydrogen
Component Composition/% Absolute amount/t.a-1
Hydrogen 98.16 7 570
Nitrogen 0.10 107
Methane 0.71 436
Ethylene 0.29 311
Ethane 0.25 288
C3–C5 0.49 912
As can be seen from the data in Tables 1 and 2, the purity of the recovered hydrogen reaches 98.16%, a level that meets the requirements of most hydrogenation units. There are many FCC units in our country, and the widespread use of this technology will provide refineries with a considerable amount of cheap hydrogen. 2.2 Coking dry gas as a raw material for hydrogen production [3,4] Coking dry gas contains 10%–14% of C2–C4 cracked olefins and 30–60 g/m3 of sulfur; such a raw material does not meet the requirements of catalysts used for efficient hydrogen production. In 1994, Changling Refining and Chemical Complex collaborated with the Research Institute of Petrochemicals (RIPP) to use the RS-200 catalyst developed by RIPP. Under conditions of a temperature of 230–320 °C, a pressure of 1.6–2.1 MPa, and a space velocity of 1,000 h-1, hydroprocessing of coker dry gas reduced the total sulfur content to below 0.3 mg/m3 and the olefin content to below 0.3%. The Changling Refining and Chemical Complex uses hydroprocessed coker dry gas as raw material and high-efficiency hydrogen production catalysts for industrial production, achieving satisfactory results; the performance data of this industrial operation are shown in Tables 3 and 4. Table 3 Results of Hydrogenation Refining of Coking Dry Gas Item Result Hydrogenation Conditions Pressure/MPa: 1.6–2.1 Inlet Temperature/°C: 230–280 Outlet Temperature/°C: ≤320 Bed Temperature/°C: 30–88 Contents of Key Components in the Dry Gas after Hydrodesulfurization Total Sulfur/mg·m-3
TECHNOLOGIES FOR COMPREHENSIVE UTILIZATION OF REFINERY GAS
Qiao Yingbin (SINOPEC Technological Development Center, Beijing 100029)
Abstract: The domestically developed technologies for utilizing hydrogen, ethylene, propylene, and butylenes derived from refinery gas are reviewed. These technologies include: the separation of hydrogen from FCC dry gas using membranes; hydrotreating coker gas to produce feedstock for steam reforming; the alkylation of ethylbenzene from FCC dry gas without prior treatment; the production of polypropylene, acrylonitrile, and isopropyl alcohol from propylene; and the manufacture of MTBE, butadiene, isobutylene, and methyl ethyl ketone from butylenes. There is still an urgent need for further comprehensive utilization of refinery gas to produce products with high added value.
Key Words: Refinery gas; Comprehensive utilization; Petrochemical industry; Review
1. Introduction
China’s refineries have a crude oil processing capacity of approximately 200 million tons per year. Due to the high proportion of heavy fractions in crude oil, secondary processing units play a significant role in these refineries. For example, the processing capacity of catalytic cracking (FCC) units is around 60 million tons per year; there are many units for the secondary processing of crude oil, and there is also an abundant supply of refinery gas. In particular, the DCC, MGG, and MIO technologies developed in China in recent years [1] have enabled the production of ethylene, propylene, and butylene to increase exponentially (or even several times), providing ample raw materials for the comprehensive utilization of refinery gas. Through years of research and development, the technologies for further processing refinery gas to produce petrochemical products have seen some of them put into industrial use, with their technical levels reaching international advanced standards. This article provides a brief introduction to the comprehensive utilization technologies for refinery gas that have been successfully developed in China. 2 Utilization technologies of dry gas: The dry gas in refineries mainly refers to FCC dry gas and delayed coking dry gas. The main components of FCC dry gas are hydrogen (accounting for 25%–40%) and ethylene (accounting for 10%–20%), while the main components of delayed coking dry gas are methane and ethane. This article mainly introduces the technologies of producing hydrogen through FCC dry gas separation and purification, producing ethylbenzene from FCC dry gas and ethylene, and using coking dry gas as a raw material for hydrogen production. 2.1 Technology for hydrogen production through catalytic cracking dry gas separation and purification［2］ The Dalian Institute of Chemical Physics, Chinese Academy of Sciences, in collaboration with Shijiazhuang Refinery, successfully developed a technology for separating and purifying hydrogen from FCC dry gas using mesoporous fiber membranes. As tested by Shijiazhuang Refinery, under conditions of a temperature of 45 ℃, a pressure of 6.1 MPa, and an osmotic pressure of 0.2 MPa, the hydrogen recovery rate using domestic separation membranes for FCC dry gas was 89.4%. This result indicates that it is feasible to use this technology for hydrogen purification via FCC dry gas separation. For a large FCC unit, the value of hydrogen recovered in one year amounts to tens of millions of yuan, resulting in significant economic benefits. The composition and quantity of dry gas and the recovered hydrogen are shown in Tables 1 and 2. The FCC unit at Shijiazhuang Refinery uses atmospheric residue as feedstock; no passivator is added during operation to produce hydrogen from the dry gas, resulting in a high hydrogen content in the dry gas. Table 1 Composition and quantity of dry gas
Component Composition/% Absolute amount/t.a-1
Hydrogen 46.49 8 460
Nitrogen 5.64 14 249
Methane 19.99 28 943
Ethylene 6.11 15 462
Ethane 12.40 33 648
C3–C5 9.37 42 194
Table 2 Composition and quantity of the recovered hydrogen
Component Composition/% Absolute amount/t.a-1
Hydrogen 98.16 7 570
Nitrogen 0.10 107
Methane 0.71 436
Ethylene 0.29 311
Ethane 0.25 288
C3–C5 0.49 912
As can be seen from the data in Tables 1 and 2, the purity of the recovered hydrogen reaches 98.16%, a level that meets the requirements of most hydrogenation units. There are many FCC units in our country, and the widespread use of this technology will provide refineries with a considerable amount of cheap hydrogen. 2.2 Coking dry gas as a raw material for hydrogen production [3,4] Coking dry gas contains 10%–14% of C2–C4 cracked olefins and 30–60 g/m3 of sulfur; such a raw material does not meet the requirements of catalysts used for efficient hydrogen production. In 1994, Changling Refining and Chemical Complex collaborated with the Research Institute of Petrochemicals (RIPP) to use the RS-200 catalyst developed by RIPP. Under conditions of a temperature of 230–320 °C, a pressure of 1.6–2.1 MPa, and a space velocity of 1,000 h-1, hydroprocessing of coker dry gas reduced the total sulfur content to below 0.3 mg/m3 and the olefin content to below 0.3%. The Changling Refining and Chemical Complex uses hydroprocessed coker dry gas as raw material and high-efficiency hydrogen production catalysts for industrial production, achieving satisfactory results; the performance data of this industrial operation are shown in Tables 3 and 4. Table 3 Results of Hydrogenation Refining of Coking Dry Gas Item Result Hydrogenation Conditions Pressure/MPa: 1.6–2.1 Inlet Temperature/°C: 230–280 Outlet Temperature/°C: ≤320 Bed Temperature/°C: 30–88 Contents of Key Components in the Dry Gas after Hydrodesulfurization Total Sulfur/mg·m-3
First is hydrogen production; second is recycling it as fuel for heating furnaces, which enables both energy recovery and environmental protection.
We do the same thing by using it as fuel for heating furnaces, but I think it’s better to use it for hydrogen production – it’s a shame to burn it!