Patent GB-759785-A (GB)
Title: Manufacture of combustible gas
Inventor: WILLIAMS NORMAN HENRY
Filed: 1954-02-08
Abstract: 759,785. Oil-gas. HUMPHREYS & GLASGOW, Ltd. Jan. 7, 1955 [Feb. 8, 1954], No. 3629/54. Class 55(2). In a cyclic catalytic process for the manufacture of combustible gas from liquid hydrocarbons comprising alternate heating and gasproducing phases and in which the gas is made in two stages, a lean gas stage and a rich gas stage, the gasification medium during a gasproducing phase and/or during a heating phase, the air or other oxygen gas for burning carbon deposited in the plant is or are supplied at a lower temperature to the rich gas stage than to the lean gas stage. The apparatus shown in Fig. 1 comprises two gas-making chambers 10 and 11 and a combustion chamber 12 connected by lines 13 and 14 so that gas-flow is from the chamber 12 in series through the two gasmaking chambers. Each of the gas-making chambers has a contact bed, in the case of chamber 10 incorporating a catalyst and in the case of chamber 11 incorporating a catalyst or consisting of refractory material. The combustion chamber 12 has a refractory lining and connection 17, 18 and 19 for supplying air, steam and heating fuel respectively. A gas outlet connection 20 from the base of gas-making chamber 11 leads through. two-way valve 21 either through a waste-heat boiler 22 to stack for waste gases or through a washer 24 for the combustible gas. In operation the plant is raised to operating temperatures by combustion of heavy fuel oil in the combustion chamber 12. Thereafter heavy oil is sprayed into the gasmaking chamber 10 to react with steam admitted by connection 18 and preheated in passing through the combustion chamber. The gases from chamber 10 pass by line 14 into the gas-making chamber 11 into which gas-oil is sprayed during a part or the whole of the gasproducing phase. Non-preheated steam may be introduced into chamber 11 by connection 25 and some of the gases from chamber 10 may bypass chamber 11 via line 27 to reduce the operating temperature in chamber 11. Alternatively a heat exchanger (not shown) may be interposed between the two chambers so that the gases from chamber 10 are cooled before entering chamber 11. Cooled stored make-gas may also be added to chamber 11 through a connection 28. In the ensuing heating phase in which carbon is burnt off the contact masses in chambers 10 and 11 non-preheated air, steam or cooled waste gases may be introduced into the chamber 11 to prevent too high a temperature developing therein. Also a portion of the hot gases from chamber 10 may by-pass chamber 11 via line 27. In a modification the separate combustion chamber is omitted and the process is heat regenerative, two regenerators being employed to recover sensible heat from the make-gas and the waste gases of the heating phase. The regenerators are used for preheating the gasification medium and the combustion air, the gasification medium and/or the combustion air supplied to the lean gasproducing stage being passed through the whole of a regenerator while the gasification medium and/or the combustion air supplied to the rich gas-producing stage is passed only through the cooler part of the regenerator. Also the gaseous products from the lean gasproducing stage are passed through the whole of a regenerator while the gaseous products from the rich gas-producing stage are passed only through the cooler part of the regenerator. Provision' is made in each gas-producing chamber for supply of heating fuel and air for supplementary heating of the plant. In this modification the major part at least of the lean gas is not passed through the rich gas stage as set out in Specification 759,784. The heating phases may be carried out as set forth in Specification 701,594 or Specification 756,386.