On demand synthesis gas from methanol
A reactor system and a process for carrying out the methanol cracking and reverse water gas shift reaction of a feedstock comprising methanol to synthesis gas are provided, where the heat for the endothermic methanol cracking and reverse water gas shift reaction is provided by resistance heating.
1. A reactor system for production of synthesis gas from a feedstock comprising methanol in the presence of a catalyst under methanol cracking and reverse water gas shift reaction conditions, said reactor system comprising:
a supply of feedstock comprising methanol and water;
a structured catalyst arranged for catalyzing methanol cracking and reverse water gas shift reactions of said feedstock, said structured catalyst comprising a macroscopic structure of an electrically conductive material, said macroscopic structure supporting a ceramic coating, wherein said ceramic coating supports a catalytically active material;
a pressure shell housing said structured catalyst, said pressure shell comprising an inlet for letting in said feedstock and an outlet for letting out product gas, wherein said inlet is positioned so that said feedstock enters said structured catalyst in a first end of said structured catalyst and said product gas exits said structured catalyst from a second end of said structured catalyst;
a heat insulation layer between said structured catalyst and said pressure shell;
at least two conductors electrically connected to said structured catalyst and to an electrical power supply placed outside said pressure shell, wherein said electrical power supply is dimensioned to heat at least part of said structured catalyst to a temperature of at least 500° C. by passing an electrical current through said macroscopic structure, wherein said at least two conductors are connected to the structured catalyst at a position on the structured catalyst closer to said first end of said structured catalyst than to said second end of said structured catalyst, and wherein the structured catalyst is constructed to direct an electrical current to run from one conductor substantially to the second end of the structured catalyst and return to a second of said at least two conductors;
an outlet for a first product gas comprising synthesis gas.
2. The reactor system according to claim 1 , wherein said structured catalyst is arranged to catalyze the methanation and steam reforming reactions.
3. The reactor system according to claim 1 , wherein said electrical power supply is dimensioned to heat at least part of said structured catalyst to a temperature of at least 700° C.
4. The reactor system according to claim 1 , wherein the feedstock additionally comprises CO 2 .
5. The reactor system according to claim 1 , wherein the feedstock additionally comprises H 2 , N 2 , CH 4 and/or Ar.
6. The reactor system according to claim 1 , further comprising electrically insulating parts provided in the structured catalyst and positioned between the at least two conductors.
7. A process for carrying out the methanol cracking and reverse water gas shift reaction of a feedstock comprising methanol and water to synthesis gas in the presence of a catalyst under methanol cracking and reverse water gas shift reaction conditions, in a reactor system comprising a pressure shell housing a structured catalyst arranged for catalyzing said methanol cracking and reverse water gas shift reactions of a feedstock, said structured catalyst comprising a macroscopic structure of electrically conductive material, said macroscopic structure supporting a ceramic coating, wherein said ceramic coating supports a catalytically active material; wherein said reactor system is provided with heat insulation between said structured catalyst and said pressure shell; said process comprising the steps of:
pressurizing said feedstock,
supplying said pressurized feedstock to said pressure shell through an inlet positioned so that said feedstock enters said structured catalyst in a first end of said structured catalyst; allowing the feedstock to undergo a methanol cracking and reverse water gas shift reaction over the structured catalyst and outletting a product gas from said pressure shell, wherein said product gas exits said structured catalyst from a second end of said structured catalyst;
supplying electrical power via electrical conductors connecting an electrical power supply placed outside said pressure shell to said structured catalyst, allowing an electrical current to run through said macroscopic structure, thereby heating at least part of the structured catalyst to a temperature of at least 500° C., wherein said at least two conductors are connected to the structured catalyst at a position on the structured catalyst closer to said first end of said structured catalyst than to said second end of said structured catalyst, and wherein the structured catalyst is constructed to direct an electrical current to run from one conductor substantially to the second end of the structured catalyst and return to a second of said at least two conductors, thereby heating at least part of the structured catalyst to a temperature sufficient for said feedstock to undergo the methanol cracking and reverse water gas shift reaction over the structured catalyst, thereby heating at least part of the structured catalyst to a temperature sufficient for said feedstock to undergo the methanol cracking and reverse water gas shift reaction over the structured catalyst,
outletting a first product gas comprising synthesis gas from the reactor system.
8. The process according to claim 7 , wherein the first product gas comprising synthesis gas from the reactor system is provided to an adiabatic post converter comprising a fifth catalyst active for catalyzing steam methane reforming, methanation and reverse water gas shift reactions; and in said adiabatic post converter, letting at least a part of the product gas stream and a heated CO 2 rich gas stream undergo steam methane reforming, methanation and reverse water gas shift reactions to thereby provide a second product gas, said second product gas being a CO rich synthesis gas stream.
9. The process according to claim 7 , wherein the process further comprises the step of feeding the first product gas or the second product gas comprising synthesis gas to an upgrading unit and separating it into an upgraded synthesis gas stream and one or more off-gas stream.
10. The process according to claim 9 , wherein the process further comprises the step of recycling one or more of the off-gas streams to upstream units of said upgrading unit.
11. A method for rapidly switching a metal-catalysed methanol cracking and reverse water gas shift reaction of a feedstock comprising methanol in a reactor system according to claim 1 , from a first steady-state reaction condition (A) to a second steady-state reaction condition (B) or vice-versa; said method comprising the steps of:
in said first steady-state reaction condition (A):
supplying said feedstock to the reactor system in a first total flow, and
supplying a first electrical power via electrical conductors connecting an electrical power supply placed outside said pressure shell to said structured catalyst, thereby allowing a first electrical current to run through said electrically conductive material,
thereby heating at least part of the structured catalyst to a first temperature at which said feedstock is converted to a first product gas mixture over said structured catalyst under said first steady-state reaction conditions (A); and said first product gas is outlet from the reactor system;
and, in said second steady-state reaction condition (B):
supplying said feedstock to the reactor system in a second total flow,
supplying a second electrical power via electrical conductors connecting an electrical power supply placed outside said pressure shell to said structured catalyst, thereby allowing a second electrical current to run through said electrically conductive material,
thereby heating at least part of the structured catalyst to a second temperature; at which said feedstock is converted to a second product gas mixture over said structured catalyst under said second steady-state reaction conditions (B); and said second product gas is outlet from the reactor system;
wherein said second electrical power is higher than said first electrical power; and/or said second total flow is higher than said first total flow.