| 摘要 |
<p>1492761 Mixing liquified gases SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 5 Nov 1974 [7 Nov 1973] 47798/74 Heading B1C A method for the production and distribution of liquefied petroleum gas in the gas phase comprises mixing in the liquid phase two LPG's of different volatility (for example propane and butane) so that the saturated vapour pressure of the mixture does not exceed a predetermined value P 0 which is equal to or greater than the consumption pressure P u , vapourising the mixture, and reducing the pressure of the gas so obtainable to P u . The method renders subsequent re-condensation unlikely. An apparatus comprises a mixing vessel 16 to which LPG of lesser volatility (e.g. butane) is supplied from a container 12 through a valve 24 controlled to maintain the liquid level in the vessel 16 between level sensors 54, 56. A LPG of greater volatility (e.g. propane) is supplied from a container 14 through a valve 38 which is controlled by a vapour pressure sensor 58, which senses the drop in saturated vapour pressure caused by the supply of butane and causes propane to be supplied until the saturated vapour pressure in the vessel reaches a predetermined value P 0 . The mixed liquefied gases are recirculated, preferably through a heat exchanger 52, and returned as droplets to the vessel 16 in order to equalize temperatures and pressures in the vessel and maintain it near the ambient temperature; the propane supply line 36 is advantageously connected to the recirculation line 50. The mixed liquefied gases are supplied to a vapourizer 18 and thence to a pressure regulator 20 arranged to supply gas at the supply pressure P u to the supply line 10. A fall in the ambient temperature will cause a greater proportion of propane to be supplied in order to maintain the pressure P o , and vice versa. Should the fall in ambient temperature be so great that the pressure P o cannot be reached, the valve 38 will be closed when the liquid level in vessel 16 reaches a maximum level sensor 60. In a modification the level sensor 56 may be dispensed with and butane supplied in a fixed time. In another modification the control of the valves 24, 38 may be reversed, so that propane is supplied until the liquid level reaches 56 and the vapour pressure is then reduced to P o by addition of butane. In another embodiment see Fig. 5 (not shown) the vapourizer and mixing vessel are combined.</p> |
