| 摘要 |
<p>The invention provides an improvement in the conventional operation of a vacuum pipestill, whereby when used with, for example, an atmospheric residuum either(a) conventional yields are obtainable with less stripping steam utilisation, or (b) a deeper cut into the residuum is obtainable for conventional steam utilisation. Some of the gaseous mixture normally withdrawn from the top of the vacuum pipestill for washing and removal is fed into compression and recycle means and recycled to the stripping zone of the pipestill to replace, or augment, the conventionally used stripping steam.</p> |
