GB390849A - Improvements relating to the production of hydrogen and carbon monoxide - Google Patents

Abstract

<PICT:0390849/III/1> A mixture of hydrogen and carbon monoxide, with or without nitrogen, is produced from gaseous hydrocarbons, such as methane, and steam, with the addition of air or air and oxygen when a mixture of nitrogen and hydrogen is required for ammonia synthesis, by passing the mixed gases over preheated refractory material at temperatures in excess of 1300 DEG C., the gases being first preheated and partially reacting while passing upward through a zone of increasing temperature; the reaction is completed while the gases pass downward through a zone of decreasing temperature. Heating of the refractory material is effected by combustion of gas with air in a region between the tops of the zones prior to the introduction of the reacting gases, the process being interrupted at intervals to allow reheating to be effected. Alternatively, the temperature may be maintained by the addition of oxygen, air, or air and oxygen. Two layers of refractory material may be employed, the upper being the more refractory so as to allow of stronger heating; this layer may be formed of lumps of fused alumina or magnesia. In the apparatus shown, two vertical chambers 1, 2 connected by a horizontal passage 3 are filled to two-thirds of their height with broken firebrick or chequer brickwork 4, 4<1> above which are placed layers 5, 5<1> of broken high temperature refractory material. Pipes 6, 6<1> are provided at the base and other pipes 7 at the top. In operation, gas introduced at the pipes 7 is burnt with air entering by the pipe 6 to heat the material 5, 5<1> to 1500 DEG C., the products of combustion leaving by the pipe 6<1>. To equalize the temperature, the direction of the flow of air and withdrawal of combustion products are reversed at intervals. After the heating is complete, methane and steam in the proportion of one to three, are admitted at the pipe 6, the gases being preheated by the brickwork 4 and decomposed by the material 5, 5<1>; excess heat in the reaction products is absorbed by the brickwork 4<1> and utilized by reversing the flow of gases. Air, or air and oxygen, may be admitted by the pipes 7 in such proportions as to render the process continuous and produce, after purification, a mixture of nitrogen and hydrogen for ammonia synthesis. Specifications 116,406 and 269,711, [both in Class 55 (ii), Gas manufacture &c.], are referred to.