Pyrolysis Product Compression

A process for producing and compressing a process gas, the process comprising:

• (a) providing a feed comprising hydrocarbon, a fuel having a heating value ≥1×106 J/kg, air, and water;
• (b) compressing the air;
• (c) combusting at least a portion of the fuel with at least a portion of the compressed air to produce a heated effluent;
• (d) expanding the heated effluent to produce a decompressed effluent and a first shaft power;
• (e) vaporizing at least a portion of the water by indirectly transferring heat to the water from the decompressed effluent to produce steam;
• (f) expanding at least part of the steam of step (e) to produce decompressed steam and a second shaft power;
• (g) pyrolysing at least a portion of the feed to produce a process gas comprising ethylene;
• and
• (h) transferring to a process gas compressor at least part of the first shaft power and at least part of the second shaft power, and compressing the process gas.

A hydrocarbon pyrolysis process, the process comprising:

• (a) providing first and second feeds;
• first, second, and third fuels;
• air;
• water;
• first and second thermal pyrolysis reactors;
• a power generator;
• and a process gas compressor;
• wherein
• (i) at least part of the first reactor is pre-heated,
• (ii) at least part of the second reactor is pre-cooled, and
• (iii) the power generator includes a compressor stage, first and second expansion stages, and a heat transfer stage;
• (b) producing a first process gas and a first combustion effluent during a first time interval t1 by at least:
• (i) pyrolysing the first feed in the preheated first thermal pyrolysis reactor, which cools the first thermal pyrolysis reactor and produces a flow of a first process gas;
• (ii) conducting the first process gas to the process gas compressor;
• (iii) combusting the first fuel with a first portion of the air in the pre-cooled second thermal pyrolysis reactor, which produces a flow of a first combustion effluent and heats the second thermal pyrolysis reactor;
• (c) producing a second process gas and a second combustion effluent during a second time interval t2 by at least:
• (i) pyrolysing the second feed in the heated second thermal pyrolysis reactor, which re-cools the second thermal pyrolysis reactor and produces a flow of a second process gas;
• (ii) conducting the second process gas to the process gas compressor;
• (iii) combusting the second fuel with a flow of a second portion of the air in the first thermal pyrolysis reactor, which re-heats the first thermal pyrolysis reactor and produces a flow of a second combustion effluent;
• (d) generating first and second shaft powers during t1 and t2 by at least:
• (i) compressing at least a third portion of the air in the compressor stage;
• (ii) combusting at least a portion of the third fuel with at least a portion of the compressed air which heats the compressed air;
• (iii) expanding the heated compressed air in the first expansion stage to produce decompressed air and the first shaft power;
• (iv) transferring heat from the decompressed air to the water in the heat transfer stage, to vaporize at least a portion of the water to produce steam;
• and
• (v) expanding at least a portion of the steam in the second expansion stage to produce decompressed steam and the second shaft power;
• and
• (e) transferring at least a portion of the first shaft power and at least a portion of the second shaft power to the process gas compressor to compress at least a portion of the first process gas during t1 and to compress at least a portion of the second process gas during t2.

An apparatus for producing and compressing a process gas, the apparatus comprising

• (a) a flow-through reactor having an internal volume which includes opposed first and second regions, the flow-through reactor being configured to receive a feed comprising hydrocarbon and to pyrolyse the feed which produces a process gas comprising C2+ olefin,
• (b) a power generator which produces shaft power, wherein the power generator includes
• (i) a compressor stage configured to compress a first working fluid which comprises at least one oxidant,
• (ii) a combustion stage configured to combust a fuel having a heating value ≥1×106 J/kg with at least a portion of the first working fluid's oxidant and to heat the compressed first working fluid,
• (iii) a first expansion stage configured to decompress the heated first working fluid and produce a first shaft power,
• (iv) a heat transfer stage configured to transfer heat from the decompressed first working fluid to a second working fluid comprising water which produces steam, and
• (v) a second expansion stage configured to decompress the steam and produce a second shaft power;
• and
• (c) a process gas compressor which is configured to consume at least part of the first shaft power and at least part of the second shaft power to compress at least a portion of the process gas.

A reverse-flow hydrocarbon pyrolysis process, the process comprising:

• (a) providing first and second feeds;
• first, second, and third fuels;
• air;
• water;
• first and second pyrolysis reactors;
• a power generator;
• and a process gas compressor;
• wherein
• (i) the first and second feeds each comprise hydrocarbon, and the third fuel is at least partially gaseous,
• (ii) the first and second pyrolysis reactors comprise an internal volume which includes opposed first and second regions, and
• (iii) the power generator includes a compressor stage, first and second expansion stages, and a heat transfer stage;
• (b) producing a first process gas and a first combustion effluent during a first time interval tP by at least:
• (i) establishing a flow of the first feed into the internal volume of the first pyrolysis reactor toward the first region, and transferring heat from the first region to the first feed which cools the first region and heats the first feed;
• (ii) pyrolysing at least a portion of the heated first feed in the internal volume under pyrolysis conditions, to produce a flow of a first pyrolysis product toward the second region of the first pyrolysis reactor, the first pyrolysis product comprising molecular hydrogen, C2+ olefin, and condensable constituents;
• (iii) transferring heat from the first pyrolysis product to the first pyrolysis reactor's second region, which heats the second region, cools the first pyrolysis product, and condenses at least a portion of the condensable constituents to produce the first process gas;
• (iv) establishing flows of a first portion of the air and the first fuel into the internal volume of the second pyrolysis reactor toward the second region and transferring heat from the second region to at least the first portion of the air, which heats the second portion of the air and cools the second region;
• and
• (v) combusting the at least a portion of the first fuel with at least a portion of the heated first portion of the air to produce a first combustion effluent and transferring heat from the first combustion effluent to the first region of the second pyrolysis reactor, which heats the first region and cools the first combustion effluent;
• (c) producing a second process gas and a second combustion effluent during a second time interval tR by at least:
• (i) establishing a flow of the second feed into the internal volume of the second pyrolysis reactor toward the first region, and transferring heat from the first region to the second feed which cools the first region and heats the second feed;
• (ii) pyrolysing at least a portion of the heated second feed in the internal volume under pyrolysis conditions, to produce a flow of a second pyrolysis product toward the second region of the second pyrolysis reactor, the second pyrolysis product comprising molecular hydrogen, C2+ olefin, and condensable constituents;
• (iii) transferring heat from the second pyrolysis product to the second pyrolysis reactor's second region, which heats the second region, cools the second pyrolysis product, and condenses at least a portion of the condensable constituents to produce the second process gas;
• (iv) establishing flows of a second portion of the air and the second fuel into the internal volume of the first pyrolysis reactor toward the second region and transferring heat from the second region to at least the second portion of the air, which heats the second portion of the air and cools the second region;
• and
• (v) combusting the at least a portion of the second fuel with at least a portion of the heated second portion of the air to produce a second combustion effluent and transferring heat from the second combustion effluent to the first region of the first pyrolysis reactor, which heats the first region and cools the second combustion effluent;
• (d) generating first and second shaft powers by at least:
• (i) compressing at least a third portion of the air in the compressor stage;
• (ii) combusting at least a portion of the third fuel with at least a portion of the compressed air which heats the compressed air;
• (iii) expanding the heated compressed air in the first expansion stage to produce decompressed air and the first shaft power;
• (iv) transferring heat from the decompressed air to the water in the heat transfer stage, to vaporize at least a portion of the water to produce steam;
• (v) expanding at least a portion of the steam in the second expansion stage to produce decompressed steam and the second shaft power;
• and
• (e) transferring at least a portion of the first shaft power and at least a portion of the second shaft power to the process gas compressor to compress at least a portion of the first process gas during tP and to compress at least a portion of the second process gas during tR.