Method of providing heat for chemical conversion and a process and system employing the method for the production of olefin
AssigneeLummus Technology Inc.
InventorsRichard J. Wilcox, Sanjeev Ram, Ajay Gami, Robert Brummer, Joseph Romeo
Life of this patent
Estimating the term…
Abstract
A method and system for providing heat to a chemical conversion process is advantageously employed in the production of olefin by the catalytic dehydrogenation of a corresponding hydrocarbon. The catalytic dehydrogenation process employs diluent steam operating at a steam to oil ratio which can be 1.0 or below and relatively low steam superheater furnace temperature. The process and system are advantageously employed for the production of styrene by the catalytic dehydrogenation of ethylbenzene.
Claims23
A method for providing heat to a chemical conversion process stream containing at least one chemical reactant, comprising the steps of:
- a) superheating a heat transfer fluid;
- b) transferring heat from the superheated heat transfer fluid to a process stream;
- c) dividing at least some of the heat transfer fluid into a first portion and a second portion;
- d) pressurizing the first portion of heat transfer fluid;
- e) recycling the pressurized first portion of heat transfer fluid to superheating step (a);
- and,
- f) introducing the second portion of the heat transfer fluid into the process stream.
A process for the production of olefins by the catalytic dehydrogenation of a hydrocarbon, comprising:
- a) superheating a steam feed stream in a heater comprising a plurality of heating zones;
- b) transferring heat from superheated steam to a process stream comprising diluent steam and the hydrocarbon, the heat being sufficient to effect catalytic dehydrogenation of at least a portion of the hydrocarbon in a reaction zone, wherein after transferring the heat the superheated steam becomes spent steam;
- c) splitting said spent stream into a first portion and a second portion;
- d) pressurizing the first portion of said spent steam;
- e) recycling the pressurized first portion of the spent steam to a first heating zone in the heater;
- f) recycling the second portion to a different section of the heater to a second heating zone in the heater;
- g) heating the second portion of the spent steam to regenerate superheated steam in the second heating zone;
- and
- h) combining at least a portion of the superheated steam with the process stream.
In a process for the production of styrene in a reaction zone by contacting a mixture of steam and ethylbenzene having a mass steam/oil ratio with a dehydrogenation catalyst at a dehydrogenation reaction temperature, the improvement comprising:
- combining sufficient diluent steam with ethylbenzene to reduce the mass steam/oil ratio to no more than 1.0;
- wherein superheated steam at a temperature of less than 815° C. is used to transfer sufficient heat to raise the ethylbenzene and diluent steam to the reaction temperature, and wherein a least a portion of said superheated steam is combined with the ethylbenzene to provide at least a portion of the diluent steam.
A process for the production of styrene by the catalytic dehydrogenation of ethylbenzene, said process comprising:
- a) providing at least first and second reaction zones, each reaction zone having associated therewith a catalytically effective amount of a dehydrogenation catalyst;
- b) providing a furnace having a plurality of heating zones;
- c) providing a feed stream containing a vaporized mixture of water and ethylbenzene having a steam/oil weight ration of no more than about 0.5;
- d) combining the feed stream with a first stream of superheated steam to provide a fluid stream having a steam/oil weight ratio of no more than about 1.0;
- e) contacting the fluid stream with the dehydrogenation catalyst in the first reaction zone under dehydrogenation reaction conditions to provide a first effluent;
- f) transferring heat from a second stream of superheated steam to the first effluent in a heat transfer zone associated with the second reaction zone, the second stream of superheated steam becoming a stream of spent steam after transfer of its heat to the first effluent;
- g) contacting the heated first effluent with dehydrogenation catalyst in the second reaction zone under dehydrogenation reaction conditions to provide a product stream containing styrene;
- h) dividing the stream of spent steam into first and second portions;
- i) pressurizing the first portion of spent steam;
- j) heating the pressurized first portion of spent steam in a first heating zone in the furnace to provide the second stream of superheated steam which is recycled upstream to the heat transfer zone associated with the second reaction zone;
- k) heating the second portion of the spent steam in a second heating zone in the furnace to provide the first stream of superheated steam.
Dependencies are inferred from the claim text.