| 摘要 |
<p>Plant material (for example, milled hop pellets) is placed in a pressure vessel and carbon dioxide is passed through the vessel in order to extract essential oil and resin components. Said passage is stopped after a predetermined period of time and inert gas(es) is/are used to displace said carbon dioxide and the extract(s) from said vessel to another location. If liquid carbon dioxide is used, it is displaced to an evaporator in which the extract is deposited, carbon dioxide being gasified. If supercritical carbon dioxide is used, it is displaced to a separator. Alternatively, the plant material may be steeped in liquid carbon dioxide which, after the steeping period, is displaced as aforesaid. The gases (carbon dioxide and inert) may be vented to atmosphere or recovered for re-use. Extraction using liquid carbon dioxide is isobaric whereas using supercritical carbon dioxide, the pressure in the pressure vessel is higher than in the separator.</p> |
