Abstract: For removing undesired gaseous components, e.g., SO.sub.2, from hot combustion gases (from carbonaceous fuels) by scrubbing with a regenerable absorbent, the scrubbing is conducted with a liquid physical absorbent, e.g., dimethylformamide, at a temperature less than 0.degree. C. The cooling requirements of the scrubbing process are supplied by means of an absorption-type refrigeration unit. The hot combustion gases, prior to scrubbing, are cooled in indirect heat exchange, first with air in an upper temperature range cooling zone, and then with cold combustion gas purified by the scrubbing in a lower temperature range cooling zone. The resultant heated air is used in part as (a) air for combustion, and/or in part as (b) an energy source for the operation of the absorption-type refrigeration unit. A heat pump may be used to supplement the said refrigeration unit.

Abstract: For thermally cracking heavy liquid hydrocarbons to produce gaseous olefins comprising a catalytic hydrogenating pretreatment, a separation of the hydrogenation product into a lighter fraction and a heavier fraction; passing the heavier fraction at least in part to a thermal cracking step to produce normally gaseous olefins; and withdrawing the lighter fraction, the improvement wherein the hydrogenation is conducted within the shaded area of FIG. 2, whereby said lighter fraction has a higher octane number.

Abstract: To obtain olefins by the thermal cracking of hydrocarbons, e.g., vacuum gas oil, by hydrogenation and subsequent steam cracking, an intermediate fractionation of the hydrogenate is provided so that the light fraction enriched in branched isomers can be used as fuel and the heavy fraction only is subjected to the steam cracking.

Abstract: In a process for the thermal cracking of hydrocarbons to produce olefins, improvement of recovering hydrocarbons boiling above 200.degree. C. from the thermal cracking stage, preferably removing polymeric components therefrom, catalytically hydrogenating resultant hydrocarbons boiling above 200.degree. C., and recycling resultant hydrogenated hydrocarbons to the thermal cracking stage.

Abstract: For removing undesired gaseous components, e.g., SO.sub.2, from hot combustion gases (from carbonaceous fuels) by scrubbing with a regenerable absorbent, the scrubbing is conducted with a liquid physical absorbent, e.g., dimethylformamide, at a temperature less than 0.degree. C. The cooling requirements of the scrubbing process are supplied by an absorption type refrigeration unit. The hot combustion gases, prior to scrubbing, are cooled in indirect heat exchange, first with air in an upper temperature range cooling zone, and then with cold combustion gas purified by the scrubbing in a lower temperature range cooling zone. The resultant heated air is used in part as (a) air for combustion and in part as (b) an energy source for the operation of the refrigeration unit. A heat pump may be used to supplement the absorption type refrigeration unit. Other aspects include, for example, special regenerator design and absorbent regeneration steps.

Abstract: To obtain olefins by the thermal cracking of hydrocarbons, e.g., vacuum gas oil, by hydrogenation and subsequent steam cracking, an intermediate fractionation of the hydrogenate is provided so that the light fraction enriched in branched isomers can be used as fuel and the heavy fraction only is subjected to the steam cracking.