Patent GB-710894-A (GB)
Title: Improvements in and relating to heat regenerative catalytic process
IPC: B01J8/02
Filed: 1951-11-14
Abstract: In the production of olefins and diolefins by dehydrogenation of saturated aliphatic hydrocarbons, the gaseous reactants are passed through channels in a heated refractory mass into a reaction chamber containing catalyst, and the reaction products are cooled by passing them through channels in a similar mass, the time of residence of the gases in each of the refractory masses not exceeding 0.3X second, and in the reaction zone not exceeding 0.05X second, where X is the pressure in absolute atmospheres at which the reaction is carried out, and the pressure drop through the apparatus not exceeding 5 lbs. per sq. in.  In order to maintain the refractory masses at the required temperature, the reaction period may be alternated with a heating step which comprises passing a combustible mixture of fuel gas and oxygen-containing gas through the apparatus in the reverse direction.  Part of the heat for the endothermic reaction may be provided by partially burning the reactant gas by mixing it with oxygen or air; alternatively the reaction may be made continuous by supplying all the heat in this way and periodically reversing the direction of gas flow through the apparatus.  Reference is made to the conversion of butane to butylene, the use of chromium oxide as catalyst, and to carrying out the reaction under sub-atmospheric pressure.ALSO:An endothermic catalytic gas reaction is carried out by passing the reactants through channels in a heated refractory mass 1 into reaction chamber 4 containing catalyst, and cooling the reaction products by passing them through channels in a similar mass 2, the time of residence of the gases in each of the refractory masses not exceeding 0.3 X second, and in the reaction zone not exceeding 0.05 X second, where X is the pressure in absolute atmospheres at which the reaction is carried out, and the pressure drop through the apparatus not exceeding 5 lbs. per sq. in.  In order to maintain the refractory masses at the required temperature, the endothermic reaction may be continued for a period of 1/2 -3 minutes and alternated with a heating step which comprises passing a combustible mixture of fuel gas and oxygen-containing gas through the apparatus in the reverse direction.  When the gas treated is combustible, it may be mixed with oxygen or air and partially burned to provide some of the heat for the endothermic reaction; in this case the production step may last for one minute and the heating step for 1-4 seconds.  Alternatively the endothermic reaction may be made continuous by supplying all the heat necessary by burning part (e.g. 15-40 per <PICT:0710894/III/1> cent.) of the reactant gas, and by reversing the direction of gas flow through the apparatus, e.g. every 1-3 minutes.  Reactions referred to are the reforming of natural gas or petroleum hydrocarbons to produce heating or synthesis gas, and the dehydrogenation of saturated aliphatic hydrocarbons to produce olefins and diolefins.  Examples describe continuous and intermittent processes for the production of a heating gas containing carbon monoxide and hydrogen from a mixture of natural gas, air, and steam, and an intermittent process for producing a hydrogen-containing gas from a mixture of propane and steam.  In the examples, the catalyst consists of nickel pellets; other suitable catalysts for these reactions are chromium, cobalt, iron, p  copper, silver, and oxides and salts thereof; for the reforming of methane and higher hydrocarbons to produce heating gas or unsaturated compounds and aromatics, alumina or silicon carbide may be used as surface active material; a chromium oxide catalyst may be used for dehydrogenation, e.g. of butane to butylene.  The refractory masses should not exceed 15 feet in length, the volume of the reaction chamber should not exceed 60 per cent. of the combined volume of the channels in both the masses, the maximum width of the channels should not exceed 0.75 inch, and the raio of the total volume of the channels to the total volume of the mass should not exceed 1 : 3.  Burners 6 are used at the start of the operation to heat the catalyst bed and the refractory masses; the catalyst bed may be raised to a temperature of 1100 DEG -1300 DEG  C., the inner ends of the masses to about 1000 DEG  C., and the outer ends to about 100 DEG  C.  Reaction may be carried out under reduced or increased pressure.  Specifications 697,108, [Group XIII], 705,393 and 708,832 are referred to.