METHOD AND PLANT FOR SEPARATING CARBON DIOXIDE FROM CRUDE GASES CONTAINING METHANE
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Abstract
A method for removing carbon dioxide from methane-containing crude gases, especially biogas, by pressure scrubbing, using a physical solvent, includes circulating the contaminated scrubbing solution after regeneration. A plant suitable for carrying out the method considerably reduces the methane loss which arises through methane slippage and improves the overall energy balance of the method. Laden scrubbing solution obtained from the pressure scrubbing is treated at least in one flash stage before the first stripping stage. In addition, a nitrogen, oxygen, carbon dioxide and methane-containing gas mixture drawn off from the flash stage is cleaned in a scrubbing stage by purified scrubbing solution drawn off from the second stripping stage and supplied in countercurrent, forming a high-purity methane gas.
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Citations
34 Claims
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1-17. -17. (canceled)
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18. A method of purifying crude gases, including biogas, containing methane and hydrogen sulfide, the method comprising the following steps:
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desulfurizing accruing crude gas and removing carbon dioxide from the crude gas by pressure scrubbing using a physically acting scrubbing solution supplied in countercurrent and dissolved in the scrubbing solution; drawing-off purified biogas; purifying laden scrubbing solution in at least two successive stripping stages including a first and a second stripping stage and thereafter supplying the purified laden scrubbing solution again to the pressure scrubbing; treating the laden scrubbing solution accruing from the pressure scrubbing upstream of the first stripping stage in at least one flash stage; and additionally purifying the gas mixture drawn off from the at least one flash stage containing nitrogen, oxygen, carbon dioxide and methane in a scrubbing stage using the purified scrubbing solution drawn off from the second stripping stage and supplied in countercurrent, producing a methane gas of high purity. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification