US 4,166,830 AGranted

Diacritic cracking of hydrocarbon feeds for selective production of ethylene and synthesis gas

OwnerEugene D. Guth, LeGrand A. Daly +1inventors

InventorsEugene D. Guth, LeGrand A. Daly, John K. Arand

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Abstract

A continuous process for the selective production of ethylene by the diacritic cracking of heavy hydrocarbon feeds such as residual oils, heavy vacuum gas oils, atmospheric gas oils, crude oils and coal-derived liquids. The diacritic cracking takes place in a non-tubular multi-zone reactor at elevated pressures (e.g. 70-1000 p.s.i.a.) A fuel is combusted with oxygen in the first section of the multi-zone reactor. The high temperature products of combustion of the first zone pass into a second section of the reactor where the feed is atomized and cracked to yield products including ethylene, acetylene and synthesis gas. The reaction products of the second zone then pass into a third section in which they are quenched. In each stage of the reactor the present process seeks to prevent the build-up of coke deposits on the walls of the reactor. In the first two stages, a film of gas such as CO.sub.2 or N.sub.2 is injected along the inner walls to prevent build-up of coke. In the quench section, the liquid material introduced as the quenching fluid also acts as a barrier to prevent coking.

Claims56

Dependent claims

A method for the diacritic cracking of hydrocarbon feedstocks to obtain high yields of ethylene at a pressure in the range of about 70 psia to 1,000 psia comprising the steps of:

(a) feeding into a first zone of a reactor a hydrocarbon containing fuel stream and combusting said fuel in the presence of oxygen to form gaseous combustion products having a temperature sufficient to crack a preselected hydrocarbon feedstock;
(b) passing said combustion products into a second zone of said reactor in which sad preselected hydrocarbon feedstock is injected into said combustion products causing said hydrocarbon feed stock to react and be diacritically cracked so as to selectively form a gaseous product stream comprising a substantial yield of gaseous ethylene, synthesis gas, and said combustion products, said hydrocarbon feedstock being in said second zone for a residence time period of about 3 to 10 milliseconds and at a temperature of about 2400.degree. to 2500.degree. F. to allow said selective diacritic cracking to occur;
(c) passing into said second zone of said reactor an inert gas to form a gas film primarily along the wall surfaces of said reactor to minimize the deposit of coke in said second zone, said coke having been formed by the combustion of the hydrocarbon fuel in said first zone and by the cracking of the hydrocarbon feedstock in said second zone;
and
(d) cooling said gaseous product stream from said second zone in a third zone of said reactor to terminate further cracking and reactions, thereby optimizing the yield of ethylene.

2 more elements

A method for the diacritic cracking of heavy hydrocarbon feedstocks selected from the group consisting of crude oils, residual oils, vacuum gas oils, atmospheric gas oils, heavy grades of petroleum oils, coal derived liquids and mixtures thereof, to obtain ethylene, light olefins and synthesis gas at a pressure in the range of about 70 psia to 1,000 psia comprising the steps of:

(a) feeding a liquid hydrocarbon fuel into a first zone of a multi-zone reactor;
(b) feeding an oxygen stream into said first zone;
(c) combusting in said first zone said hydrocarbon fuel and said oxygen to form gaseous combustion products having a temperature sufficient to crack a preselected hydrocarbon feedstock;
(d) passing said combustion products into a second zone of said reactor in which said preselected hydrocarbon feedstock is injected in atomized droplets into said combustion products causing said hydrocarbon feedstock to react and be diacritically cracked so as to selectively form a gaseous product stream comprising a substantial yield of gaseous ethylene, synthesis gas, and said combustion products, said hydrocarbon feedstock being in said second zone for a residence time period of 3 to 10 milliseconds and at a temperature of about 2400.degree. to 2500.degree. F. to allow said diacritic cracking to occur;
(e) passing into said second zone of said reactor an inert gas to form a gas film primarily along the wall surfaces of said reactor to minimize the deposit of coke on said wall surfaces in said second zone, said coke having been formed by the combustion of the hydrocarbon fuel in said first zone and by the cracking of the feedstock in said second zone;
and
(d) promptly cooling said gaseous product stream from said second zone in a third zone of said multi-stage reactor to terminate further cracking and reactions thereby optimizing the yield of ethylene.

4 more elements

Dependencies are inferred from the claim text.