Abstract:
This method comprises: forming an expanded intermediate recirculation stream (170) from a liquid (112, 128) obtained during an upstream cooling and/or intermediate cooling step, upstream from the downstream cooling step; circulating the intermediate recirculation stream (170) at least in an upstream heat exchanger (42) to cool an upstream stream of cracked gas (102); reintroducing the reheated intermediate recirculation stream (170) in a raw cracked gas (20) upstream from at least one compressor (36, 38) of a cooling and compression stage (24). The upstream, intermediate and downstream cooling steps is carried out without a heat exchanger respectively of an upstream stream of cracked gas (102), an intermediate stream of cracked gas (114) and a downstream stream of cracked gas (140) with an external refrigeration cycle.
Abstract:
This method comprises the following steps: treating a feed stream (12) to obtain a treated gas stream (60); cooling the treated gas stream (60) in a heat exchanger (34) to form at least one column feed fraction; feeding each column feed fraction into a distillation column (50); heating at least one downstream flow (106) derived from the column head stream (104) in the heat exchanger (34). The treatment step comprises the forming of an intermediate stream (20) containing at least 20 mole % ethylene and at least 20 mole % carbon monoxide, the method comprising a step to remove the carbon monoxide contained in the intermediate stream (20).
Abstract:
A method for producing a stream of propylene and associated facility are described. The method includes: an introduction of a feed cut rich in C4 and/or C5 hydrocarbons, and at least one cut rich in ethylene into a metathesis reactor; an introduction of a metathesis product in a deethylenizer; a production of an overhead stream rich in ethylene and a feed stream; an introduction of the feed stream into a depropylenizer and recovery of a bottom stream containing C4+ hydrocarbons; a recovery, from an overhead stream of the depropylenizer, of the propylene stream; a lateral withdrawal of a recycle stream and return of the recycle stream to the metathesis reactor; a lateral draw-off, in the depropylenizer, of a purge rich in C4 paraffinic hydrocarbons and/or rich in isobutene.