| 摘要 |
C2H4 recovery from a crude gas mixt. contg. hydrocarbons other than C2H4 takes place by compressing the crude gas mixt., cooling, separation, in several steps, into a 3+C hydrocarbon fraction, a CH4 and a 2C hydrocarbon fraction, and C2H4 separation from 2C hydrocarbon fraction. In new process, only part of 3+C hydrocarbons is separated before CH4 separation from crude gas mixt. in a pre-separation is separated in a further separation column, into a 3+C hydrocarbon fraction and a 2C hydrocarbon fraction. (i) Cooling requirement of process can be reduced by 32%. Head cooling temp. in both columns for 3+C hydrocarbons may be -20 degrees C (compared with -40 degrees C for temp. required in sharp separation of 3+C hydrocarbon fraction before CH4 separation), resulting in an 8% saving in energy requirement. (ii) Column for separating the last part of the 3+C hydrocarbons is arranged in shunt of process and is fed only with CH4 column sump fraction. |
