Abstract: A fixed bed containing a particulate catalyst or sorbent material (10) subject to operation at high temperature having a shaped boundary member (16) inclined to the direction of fluid flow through the bed that maintains the depth of said catalyst or sorbent at the boundary of the bed through a series of thermal expansion-thermal contraction cycles is described. By maintaining bed depth, the shaped boundary member (16) can prevent bypass of, e.g. ammonia through a bed of particulate ammonia oxidation catalyst.

Abstract: Ammonia oxidation by passing a mixture of air and ammonia over a catalyst containing at least one cobalt compound at an elevated temperature wherein, prior to contact with the catalyst, the air is passed through an absorber comprising a support carrying an absorbent material for acidic gases.

Abstract: A high temperature shift process using an iron oxide-containing catalyst wherein the feed gas is contacted with an iron-free, copper-containing, catalyst at an inlet temperature in the range 280-370° C. before contact with the iron oxide-containing catalyst in order to effect some shift reaction and thus avoid conditions conducive to over-reduction of the iron oxide containing catalyst.

Abstract: A high temperature shift process using an iron oxide-containing catalyst wherein the feed gas is contacted with an iron-free, copper-containing, catalyst at an inlet temperature in the range 280-370° C. before contact with the iron oxide-containing catalyst in order to effect some shift reaction and thus avoid conditions conducive to over-reduction of the iron oxide containing catalyst.

Abstract: A catalyst unit for use in an exothermic reaction, such as ammonia oxidation, comprises a material effective as a catalyst for said reaction having a shape conforming to a disc or cone having a plurality of radially extending corrugations. The catalyst unit may be disposed across a reactor with a start-up burner disposed above the catalyst unit and mounted for rotation about the axis of the reactor. The burner tube is pivoted and provided with means, for example a follower engaging with the upper surface of the catalyst unit, so that as the burner is rotated about the axis the burner tube pivots to maintain the burner tube a constant distance above the upper surface of the catalyst unit.

Abstract: Catalyst precursor pellets, suitable for use, after reduction, as high temperature shift catalysts, comprising oxides of iron and chromium and including particles having an aspect ratio of at least 2 and an average (by weight) maximum dimension of at least 500 nm. The particles are preferably acicular and particularly are acicular iron oxide, alumina, or zinc oxide particles.