Improvements in or relating to a process and apparatus for depoisoning gases

摘要

In a process for depoisoning gases by catalytic conversion of the carbon monoxide into carbon dioxide and hydrogen, the catalyst is in the form of pieces or debris and is repeatedly circulated in a hot state between the conversion chamber and a regeneration chamber, the temperature of the catalyst being maintained within a predetermined temperature range, the lower limit being the conversion temperature, e.g. 350--400 DEG C. and the upper limit by the regenerating temperature, e.g. about 800 DEG C. A suitable catalyst is the mineral ankerite containing iron lime and magnesia, and which may also serve to remove the carbon dioxide formed. The conversion of carbon monoxide takes place in the converter, 1 subdivided into chambers 2 and 3, arranged above a regenerator 4 also subdivided into two chambers 5 and 6. The conversion chambers 2 and 3 are heated or cooled by suitable gases passed through flues 9. The spent catalyst is discharged into the regenerator chambers 5 and 6, which are heated by gases introduced, mixed with air, through pipe 26. The hot combustion gases pass through a waste-heat boiler 30, the feedwater being preheated by an economizer 20 placed in the stack 21. The cooled combustion gases are discharged or used to heat chambers 2 and 3. The steam generated in the boiler is injected through openings 36 in the lower part 35 of the regenerator whereby the regenerated catalyst is cooled from about 800 DEG C. down to 400 DEG C., and the regeneration of the catalyst is assisted. If necessary, other gases may be used to cool the catalyst. A part of the steam is injected via pipe 33 into the converter. The hot gases leaving the regenerator by pipe 18 may be fed to the stack or diverted into the flues 9 to heat chambers 2 and 3. If the carbon dioxide or other gases leaving the regenerator are required for other purposes, they are discharged through pipe 38. The regenerated catalyst is fed into a bunker 41 and thence into a wagon 43 which is lifted to the top of the structure and discharges the catalyst into bunkers 47 and 49. The feeding device between the parts of the apparatus comprises a vertically reciprocable cylindrical sleeve 51 operating in a circular neck portion of the appropriate bunker or chamber. A cone 52 is attached to the lower part of sleeve 41, and a stationary distributing cone 50 is fixed above the neck. The sleeve 51 intercepts the falling catalyst before the cone 52 fits on its seating, thus giving a gas-tight seal without jamming of the catalyst. An appropriate gas pressure is maintained in the bunkers &c. to prevent gas leakage during transfer of the catalyst. All the feeding devices are operated in timed relationship so that catalyst is removed from the converter as it becomes inactive. The inlet and outlet conduits for the converter chambers 2 and 3, are so arranged that, for example, the gas passes up it through chamber 2, and is preheated by the hot catalyst before it mixes with the steam from pipes 33 and is converted by downward passage through chamber 3. The flow is then reversed. If desired, a battery may be arranged with the converters and regenerators side by side, so that the catalyst may be fed to any desired chamber. Fig. 5 shows diagrammatically the combination of the above process with a water-gas generator. During the blast period, primary air is fed from the compressor 86 to the water-gas generator 81, and the hot blase gases flow to the regenerator 84, and art burnt with air introduced through pipe 88, the regenerator taking the place of the usual heat storage chamber and the catalyst the place of the usual refractory checkerwork. The hot combustion products are used to produce steam in the boiler 82 and are then discharged through the stack 90. The water gas produced in the generator during the next period passes through the regenerator where it is preheated by the hot catalyst, and then to the converter 83, where it is converted into hydrogen and carbon dioxide with the aid of steam fed through pipe 92. The treated gas passes through coolers 94 to storage or user. The steam required for the water-gas generator is supplied through pipe 93.