Improvements in or relating to the production of acetylene and ethylene

摘要

In the production of acetylene and ethylene either by partial combustion of a hydrocarbon followed by addition of a light hydrocarbon oil having an initial boiling point of 50 DEG C, and a dry point of 250 DEG C. or by the pyrolysis of a hydrocarbon, and the effluent is quenched with a raw crude petroleum oil. Fig. 1 depicts a partial combustion process in which methane and oxygen are preheated, mixed in mixing zone 3, passed through distributer 6 and burned. A light hydrocarbon oil boiling in the range 50 DEG -250 DEG C. is injected through nozzles 8 from line 9 to reduce the temperature to 500 DEG -1100 DEG C., the oil itself being partially pyrolysed. The products are quenched to not less than 100 DEG C., e.g. 150 DEG -200 DEG C., by injection of recycle heavy oil and make-up crude oil through nozzles 12. The lighter components of the crude oil are vaporized and pass with the gaseous products to oil scrubber 13 where they are contacted countercurrently with recycle heavy oil to remove any carbon not removed in the quenching. Heavy oil at 150 DEG -200 DEG C. from the quench and scrubber pass to the carbon precipitator 14 whence a carbon enriched fraction is removed by line 15 for use as a fuel and heavy oil for recycle is taken by line 16. The gaseous products from oil scrubber 13 pass to water scrubber 21 where light oil, vaporized from the crude oil or unconverted from quench 8, is condensed, separated from water and recycled by line 9 to the reactor. Uncondensed gases pass to acetylene concentrator 19 where heavy acetylenes are first absorbed, then acetylene and carbon dioxide, e.g. in methanol, and recovered therefrom by heating, using the heat in the quench oil in line 16. Carbon dioxide may be dissolved out with aqueous monoethanolamine. The remaining gases may be treated at 26 to recover ethylene, other gaseous hydrocarbons which may be partially oxidised together with the methane, and hydrogen and carbon monoxide which may be used as a fuel or synthesis gas. In pyrolysis processes the apparatus is modified, the reactor and quench being as shown in Fig. 2. Fuel, together with recycle waste gases from ethylene concentrator 26, is burned with oxygen in combustion chamber 7, steam being added to control the temperature. Light oil is injected at 8 to be pyrolysed and heavy oil at 12 for quenching. Otherwise the process is the same.