Imperial Chemical Industries Limited

Godfrey C Chinchen

James R Jennings

Glyn D Short

Kenneth C Waugh

James G Williamson

Methods and apparatus for monitoring the reaction between a metal, and/or metal oxide, reactive with nitrous oxide wherein a mixture of nitrous oxide and a diluent is passed through a bed of a material containing the metal, or metal oxide, and the time to a marked change in the exit gas composition is determined. The procedure is of particular utility for metal surface area determination.

Monitoring reaction of nitrous oxide to form nitrogen

A catalyst suitable for a carbon oxides conversion process comprises metallic copper and oxides of zinc and/or magnesium and has a copper metal surface area of at least 70 m.sup.2 per g of copper. Whereas conventional catalysts are normally made by forming an intimate mixture of discrete particles of compounds of copper, and zinc and/or magnesium, and optionally at least one other element such as aluminum, calcining the composition to convert the constituents to oxides and then subjecting the calcined composition to reduction conditions so that the copper compounds therein are converted to copper, the high copper area catalysts are made by a process in which the calcination stage is omitted so that the copper compounds in the intimate mixture are reduced to metallic copper without the intimate mixture being heated to a temperature above 250.degree. C. Where the catalyst is required in pelleted form, it is preferably pelleted after reduction.

Process for the manufacture of a catalyst

A catalyst suitable for use in catalytic shift, or methanol synthesis, comprises copper, zinc oxide, magnesia, and at least one trivalent metal oxide, e.g. alumina. The amount of magnesia is such that the magnesium atoms constitute 0.2 to 7% of the total number of copper, zinc, and magnesium atoms.

Catalyst

The shift reaction of carbon monoxide with steam to give carbon dioxide and hydrogen is carried out over a catalyst comprising iron oxide and at least one further metal oxide that is difficultly reducible to metal, contains metal exerting a valency of at least 2 and is incapable of forming a mixed oxide having the spinel structure M.sup.II M.sup.III M.sub.2 O.sub.4 where M.sup.II is a divalent metal and M.sup.III is a trivalent metal.

Hydrogen production

The life of copper-containing catalysts in the low temperature shift reaction of carbon monoxide with steam is limited as a result of slow poisoning by halogen and/or sulphur compounds. It has been found that the poisoning reaction and the shift reaction occur almost entirely on the surface of the catalyst pellets, and that the rate at which a catalyst charge loses activity can be decreased by having the catalyst in an inlet zone in a form more accessible to the reacting gas than that catalyst downstream thereof. The inlet zone catalyst pieces can be smaller and/or formed with indentations or protrusions and/or more macroporous in order to provide better access.

Low temperature shift conversion process

A carbon monoxide shift process at a pressure of at least 15 atm. abs. is carried out over an oxidic and/or sulphidic catalyst of a specified level of activity in a 2-zone bed. The upstream zone has an outlet temperature in the range 350.degree.-400.degree. C. and the downstream zone has a higher outlet temperature, for example up to 550.degree. C. The catalyst in the upstream zone differs from the catalyst in the downstream zone by containing more catalytic material per unit volume and/or by having a lower area/volume ratio and/or by having a lower porosity.

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Stockton-on-Tees, United Kingdom

Godfrey C Chinchen