| 摘要 |
PROBLEM TO BE SOLVED: To provide a process and an apparatus for satisfactorily adjusting the calorific value of LNG while preventing the solidification of impurities such as methanol by a simple inexpensive structure by mixing a liquefied natural gas with a liquefied petroleum gas having a temperature higher than that of the former. SOLUTION: As regards the side of an LNG delivery passage 12, the LNG is sent to a mixer 30 by opening a shut-off valve 18, operating an LNG delivery pump 14 and regulating the flow rate of the LNG by means of a flow control valve 16. On the other hand, as regards the side of an LNG delivery passage 22, when the concentration of impurities in an LPG held in an LPG tank 20 is above the allowance, namely when the concentration of impurities is so high that the impurities cooled by mixing with the LNG in the mixer 30 are solidified and stop the passage (e.g. when the concentration of a methanol impurity in a propane-based LPG is 50ppm or above), a shut-off valve 52 is shut, a shut-off valve 28 is opened, and an LNG delivery pump 24 is operated. The flow rate is regulated by means of a flow rate control valve 26. The impurity-containing LPG is sent to a membrane separator 40, the separated impurities are discharged out of the system, and the remaining LPG is fed to the mixer 30 and mixed with a low-temperature LNG, whereupon the stoppage of the passage can be prevented. |
