Method and system for producing a synthesis gas in an oxygen transport membrane based reforming system that is free of metal dusting corrosion

Patent metadata

Field	Value
Publication number	US-9611144-B2
Application number	US-201314090289-A
Country	US
Kind code	B2
Filing date	Nov 26, 2013
Priority date	Apr 26, 2013
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

A method and system for producing a synthesis gas in an oxygen transport membrane based reforming system that utilizes a combined feed stream having a steam to carbon ratio between about 1.6 and 3.0 and a temperature between about 500° C. and 750° C. The combined feed stream is comprised a pre-reformed hydrocarbon feed, superheated steam, and a reaction product stream created by the reaction of a hydrogen containing stream reacted with the permeated oxygen at the permeate side of the oxygen transport membrane elements and wherein the oxygen transport membrane based reforming system and associated synthesis production process equipment are substantially free of carbon formation and metal dusting corrosion.

First claim

What is claimed is:

1. A method for producing synthesis gas in an oxygen transport membrane based reforming system, wherein said system comprises two distinct reactors:
at least one catalyst containing reforming reactor comprising a plurality of catalytic reforming tubes, wherein said reforming reactor is configured to produce a synthesis gas stream by reacting a combined feed stream in the presence of the catalyst and heat; and
a reactively driven oxygen transport membrane reactor proximate to said at least one catalyst containing reforming reactor, the reactively driven oxygen transport membrane reactor comprising a plurality of oxygen transport membrane elements configured to separate oxygen from an oxygen containing feed stream and produce an oxygen permeate at a permeate side of the oxygen transport membrane elements and an oxygen depleted retentate stream at a retentate side of the oxygen transport membrane elements, the method comprising the steps of:
separating an oxygen containing stream into an oxygen permeate and an oxygen depleted retentate stream using a plurality of oxygen transport membrane elements disposed in the oxygen transport membrane based reforming system;
reacting a hydrogen containing stream contacting a permeate side of the oxygen transport membrane elements with the oxygen permeate to generate a reaction product stream and heat;
pre-heating a hydrocarbon containing feed stream and combining the pre-heated hydrocarbon containing feed stream with a portion of the reaction product stream and steam to produce a combined feed stream having a temperature between about 500° C. and 750° C.;
reforming the combined feed steam in the at least one catalyst containing reforming reactor in the presence of the catalyst and heat, wherein said heat is generated said oxygen transport membrane reactor by the reaction of the hydrogen containing stream and permeated oxygen, to produce a synthesis gas stream, the at least one catalyst based reforming reactor disposed proximate the oxygen transport membrane elements;
cooling the synthesis gas stream exiting the oxygen transport membrane based reforming system in a heat exchange network fluidly coupled to the reforming reactor and the oxygen transport membrane reactor, wherein said network comprises one or more coils disposed in an oxygen depleted retentate stream duct, wherein steam is superheated via indirect heat exchange between the oxygen depleted retentate stream as the steam is directed through the one or more coils disposed in the oxygen depleted retentate stream duct, wherein said heat exchange network is configured to: (i) cool the synthesis gas stream exiting the at least one catalyst containing reforming reactor to a temperature of less than about 400° C.; (ii) produce steam, and (iii) optionally pre-heat a hydrocarbon containing feed stream; and
feeding a portion of the cooled synthesis gas stream to the permeate side of the plurality of oxygen transport membrane elements to form all or a portion of the hydrogen containing stream;
wherein the oxygen transport membrane based reforming system and associated synthesis production process equipment are substantially free of carbon formation and metal dusting corrosion.

2. The method of claim 1 further comprising the step of superheating the steam by heating the steam via indirect heat exchange with the heated retentate stream and feeding a portion of the superheated steam to the hydrocarbon containing feed stream to adjust the steam to carbon ratio and temperature of the combined feed stream.

3. The method of claim 2 wherein the superheated steam is between about 15 bar to 80 bar and between about 300° C. and 600° C.

4. The method of claim 1 wherein the step of pre-heating the hydrocarbon feed stream further comprises pre-heating the hydrocarbon containing feed stream via indirect heat exchange with the synthesis gas stream or via indirect heat exchange with the oxygen depleted retentate stream or both.

5. The method of claim 1 further wherein the step of combining the pre-heated hydrocarbon containing feed stream with a portion of the reaction product stream and steam to produce the combined feed stream further comprises mixing the hydrocarbon feed stream with superheated steam and heating the mixed stream via indirect heat exchange with the oxygen depleted retentate stream.

6. The method of claim 1 wherein the step of feeding a portion of the cooled synthesis gas stream to the permeate side of the plurality of oxygen transport membrane elements further comprises:
compressing the portion of the cooled synthesis gas stream while maintaining the temperature of the cooled, compressed portion of the synthesis gas stream at a temperature less than about 400° C.; and
directing the cooled, compressed portion of the synthesis gas stream to the permeate side of the oxygen transport membrane elements to react with the oxygen permeate to generate the reaction product stream and heat.

7. The method of claim 1 further comprising the steps of:
Feeding the oxygen depleted retentate stream to a duct burner where it reacts with a source of supplemental fuel to produce a heated exhaust stream; and
heating the oxygen containing stream via indirect heat exchange with the heated exhaust stream using a continuously rotating ceramic regenerator disposed in operative association with the oxygen containing stream and the heated retentate stream.

8. The method of claim 1 further comprising the steps of further cooling the synthesis gas stream with one or more of the following streams: a boiler feed water stream in an economizer to produce heated boiler feedwater; a feed water stream in a feed water heater to heat the feed water; or a cooling water stream in a cooling water heat exchanger.

9. An oxygen transport membrane based reforming system for producing synthesis gas which comprises two distinct reactors, said system comprising:
a reactor housing;
at least one catalyst containing reforming reactor comprising a plurality of catalytic reforming tubes disposed in the reactor housing and configured to produce a synthesis gas stream by reacting a combined feed stream in the presence of the catalyst and heat; and
a reactively driven oxygen transport membrane reactor disposed in the reactor housing proximate the at least one catalyst containing reforming reactor, the reactively driven oxygen transport membrane reactor comprising a plurality of oxygen transport membrane elements configured to separate oxygen from an oxygen containing feed stream and produce an oxygen permeate at a permeate side of the oxygen transport membrane elements and an oxygen depleted retentate stream at a retentate side of the oxygen transport membrane elements;
a hydrogen containing stream in contact with the permeate side of the plurality of oxygen transport membrane elements, wherein the permeated oxygen reacts with the hydrogen containing stream to reactively drive the separation of oxygen from the oxygen containing feed stream and to generate a reaction product stream and heat that is transferred to the oxygen depleted retentate stream and to at least one catalyst containing reforming reactor; and

a heat exchange network fluidly coupled to the reforming reactor and the oxygen transport membrane reactor, the heat exchange network comprising one or more coils disposed in an oxygen depleted retentate stream duct, wherein steam is superheated via indirect heat exchange between the oxygen depleted retentate stream as the steam is directed through the one or more coils disposed in the oxygen depleted retentate stream duct, said heat exchange network configured to: (i) cool the synthesis gas stream exiting the at least one catalyst containing reforming reactor to a

Assignees

• Chakravarti Shrikar
• Drnevich Raymond Francis
• Burgers Kenneth L
• Praxair Technology Inc

Inventors

• Chakravarti Shrikar
• Drnevich Raymond Francis
• Burgers Kenneth L

Classifications

• C01B2203/043

  Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration · CPC title

• C01B2203/0233

  the reforming step being a steam reforming step · CPC title

• C01B2203/0827

  at least part of the fuel being a recycle stream · CPC title

• B01J2219/00006

  Large-scale industrial plants · CPC title

• C01B2203/0283

  containing a CO-shift step, i.e. a water gas shift step · CPC title