Catalytic pressure swing adsorption + membrane separation technology for hydrogen enrichment in dry gas
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At present, the hydrogen content in the catalytic dry gas from most refineries is relatively high, around 35%. Therefore, if we use membrane separation and pressure swing adsorption technologies to concentrate the hydrogen in this catalytic dry gas, the benefits would be considerable. For a catalytic cracking unit with a capacity of 800,000 tons per day, the amount of catalytic dry gas produced is around 70 tons per day, corresponding to a volume of about 4,000 cubic meters per hour; the hydrogen content in this gas is approximately 1,500 cubic meters per hour. If we build a facility for producing hydrogen from catalytic dry gas, capable of generating 1,500 cubic meters of hydrogen per hour, then the annual consumption of dry gas would be 3,000 tons, which is equivalent to 10.5 million yuan in value. If methanol is used to produce hydrogen—780 kilograms per hour of hydrogen generation—the annual consumption of methanol would be 2,340 tons, costing 7.2 million yuan. These calculations are based on 8,000 hours of operation per year. The price of dry gas is 3,500 yuan per ton, while the price of methanol is 3,000 yuan per ton. Given these profit considerations, are there any design firms willing to develop designs for directly concentrating hydrogen from dry gas?
Using catalytic dry gas results in almost no raw material costs over a year—the processed dry gas is used as fuel
The hydrogen content in the catalytic dry gas is usually quite high, around 35%. Is it really that high? In our two catalytic units, the hydrogen concentration in the dry gas is generally only around 22%
It depends on what the catalytic process is, whether the catalyst is poisoned, and how the hydrogen content in the gas changes; if it’s 35%, any design institute can handle it； 15%-22% is problematic; a high dosage is required, and coupled with the hydrogen loss from desorbed gas, it’s not very cost-effective.
Does that calculation refer to the volume fraction in the dry gas? 35%? ? ? ? ?
Here, the catalytic process used is the MGD process; the average hydrogen content in the catalyzed dry gas is generally around 21%–22% (by volume). In our facility, the dry gas goes directly to the ethane and ethylene concentration unit without undergoing any hydrogen removal treatment.
I have just finished working on the design for this set of equipment; the design institute is Beijing Yulong Institute
The raw materials for our system come from catalytic dry gas on one hand, and hydrogenated dry gas from the hydrogenation unit on the other; these are supplied as raw materials to the ethylene plant
What is the process involved in an ethane-ethylene concentration plant, what operating conditions are required, and what are the costs?
The ethylene-ethane concentration unit essentially uses a PSA unit to process gases such as catalytic dry gas; its purpose is to produce high-concentration ethylene and ethane for use in ethylene production facilities, while the remaining gas is sent to the fuel gas system for combustion.
Catalytic dry gas, generally around 20%.