Compactgtl Limited

Gtl Microsystems Ag

Ian Frederick Zimmerman

Clive Derek Lee-tuffnell

David Leslie Segal

John William Stairmand

Michael Joseph Bowe

Jason Andrew Maude

David Charles William Blaikley

Clive Derek Lee-Tuffnell

David James West

Robert Peat

Stuart Leigh Jones

Methane reacts with steam generating carbon monoxide and hydrogen in a first catalytic reactor; the resulting gas mixture undergoes Fischer-Tropsch synthesis in a second catalytic reactor. In the steam/methane reforming, the gas mixture passes through a narrow channel having mean and exit temperatures both in the range of 750&#xb0; C. to 900&#xb0; C., residence time less than 0.5 second, and the channel containing a catalyst, so that only reactions having comparatively rapid kinetics will occur. Heat is provided by combustion of methane in adjacent channels. The ratio of steam to methane may be about 1.5. Almost all methane will undergo the reforming reaction, almost entirely forming carbon monoxide. After Fischer-Tropsch synthesis, the remaining hydrogen may be fed back to the combustion channels. The steam for the reforming step may be generated from water generated by the chemical reactions, by condensing products from Fischer-Tropsch synthesis and by condensing water vapor generated in combustion.

Apparatus for steam-methane reforming

A reactor module for Fischer-Tropsch synthesis having a generally rectangular reactor block with a stack of plates defining flow channels for coolant and flow channels for the synthesis reaction arranged alternately in the block. The synthesis flow channels extend in a generally vertical direction between upper and lower faces of the reactor block and are defined by plates in combination with either bars or sheets such that each channel is of width no more than 200 mm. The coolant flow channels are oriented in the same direction, and communicate through distributor chambers with inlet and outlet ports at side faces of the reactor block. A plant may contain a multiplicity of such reactor modules operating in parallel, the modules being interchangeable and replaceable. The temperature control is enhanced by allowing the coolant flow to be parallel to the synthesis gas flow.

Catalytic reactor

A compact catalytic reactor () comprises a channel for a rapid reaction having an inlet () for a gas mixture to undergo the reaction. The channel is provided with two different catalyst structures (), a first catalyst structure () in the vicinity of the inlet () and a second catalyst structure () further from the inlet, such that a gas mixture supplied to the inlet flows past them both. The first catalyst structure () has little catalytic activity for the rapid reaction, whereas the second catalyst structure () has catalytic activity for the rapid reaction. This is applicable to combustion of gas mixtures containing hydrogen, for which the first catalyst structure () may comprise uncoated oxidized aluminum-containing ferritic steel, while the second catalyst structure () may incorporate Pt and/or Pd in an alumina support. Exhaust gases may also be recycled to the inlet () to inhibit combustion.

Catalyst structure for a rapid reaction

A catalytic reactor () comprises a plurality of sheets () defining flow channels () between them. Within each flow channel () is a foil () of corrugated material whose surfaces are coated with catalytic material apart from where they contact the sheets (). At each end of the reactor () are headers to supply gas mixtures to the flow channels (), the headers communicating with adjacent channels being separate. The reactor () enables different gas mixtures to be supplied to adjacent channels (), which may be at different pressures, and the corresponding chemical reactions are also different. Where one of the reactions is endothermic while the other reaction is exothermic, heat is transferred through the sheets () separating the adjacent channels (), from the exothermic reaction to the endothermic reaction. The reactor () may be used in a compact plant to perform steam/methane reforming, obtaining the necessary heat by catalytic methane combustion, and also for Fischer-Tropsch synthesis, so that the overall process involves conversion of methane to long-chain hydrocarbons.

Methane is reacted with steam, to generate carbon monoxide and hydrogen in a first catalytic reactor (); the resulting gas mixture can then be used to perform Fisher-Tropsch synthesis in a second catalytic reactor (). In performing the steam/methane reforming, the gas mixture is passed through a narrow channel in which the mean temperature and exit temperature are both in the range 750&#xb0; C. to 900&#xb0; C. the residence time being less than 0.5 second, and the channel containing a catalyst, so that only those reactions that have comparatively rapid kinetics will occur. The heat is provided by combustion of methane in adjacent channels (). The ratio of steam to methane should preferably be 1.4 to 1.6, for example about 1.5. Almost all the methane will undergo the reforming reaction, almost entirely forming carbon monoxide. After performing Fischer-Tropsch synthesis, the remaining hydrogen is preferably fed back () to the combustion channels (). The steam for the reforming step is preferably generated from water generated by the chemical reactions, by condensing () the products from the Fischer-Tropsch synthesis and by condensing () water vapour generated in the combustion.

Process an apparatus for steam-methane reforming

A compact catalytic reactor for Fischer-Tropsch synthesis defines a multiplicity of first and second flow channels arranged alternately in the reactor, for carrying a gas mixture which undergoes Fischer-Tropsch synthesis, and a coolant fluid, respectively. Each first flow channel contains a removable gas-permeable catalyst structure incorporating a metal substrate. A multiplicity of flow paths are defined through the catalyst structure, and the voidage, that is to say the proportion of the cross-sectional area of the first flow channel constituted by the said multiplicity of flow paths, is between 25% and 70%. This provides an optimum balance between productivity and selectivity, so that operation of the reactor can be economic and controllable.

Fischer-Tropsch synthesis is performed using a compact catalytic reactor unit () defining channels in which is a gas-permeable catalyst structure (), the channels extending between headers (). The synthesis occurs in at least two stages, as the reactor unit provides at least two successive channels () for the Fischer-Tropsch synthesis connected by a header, the gas flow velocity through the first channel being sufficiently high that no more than 65% of the carbon monoxide undergoes conversion. The gases are cooled () in the header between the two stages, so as to condense water vapor, and then pass through the second channel at a sufficiently high gas flow velocity that no more than 65% of the remaining carbon monoxide undergoes conversion. This lowers the partial pressure of water vapor and so suppresses oxidation of the catalyst.

Catalytic reactor and process

A catalytic reactor comprises a plurality of sheets defining flow channels between them. Within each flow channel is a foil of corrugated material whose surfaces are coated with catalytic material. Flow channels for a first gas extend in oblique directions relative to the flow channels for a second gas. The reactor incorporates header chambers to supply gas mixtures to the flow channels, the headers communicating with adjacent channels being separate. The reactor enables different gas mixtures to be supplied to adjacent channels, which may be at different pressures, and the corresponding chemical reactions are also different. Where one of the reactions is endothermic while the other reaction is exothermic, heat is transferred through the sheets separating the endothermic reaction. When the catalyst in one set of flow channels becomes spent, it can be replaced by removing a header.

Methane is reacted with steam, to generate carbon monoxide and hydrogen in a first catalytic reactor; the resulting gas mixture can then be used to perform Fischer-Tropsch synthesis in a second catalytic reactor. In performing the steam/methane reforming, the gas mixture is passed through a narrow flow channel containing a catalyst structure on a metal substrate, and adjacent to a source of heat, in a time less than 0.5 s, so that only those reactions that have comparatively rapid kinetics will occur. Both the average temperature and the exit temperature of the channel are in the range 750&#xb0; to 900&#xb0; C. The ratio of steam to methane should preferably be 1.4 to 1.6, for example about 1.5. Almost all the methane will undergo the reforming reaction, almost entirely forming carbon monoxide. After performing Fischer-Tropsch synthesis, the remaining hydrogen is preferably used to provide heat for the reforming reaction.

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Poole, United Kingdom

Clive Derek Lee-Tuffnell