| 摘要 |
<p>Gaseous acidic contaminants, e.g. CO2 are removed from gaseous mixtures containing them by passing the mixture through a filter element containing at least one alkali filter body said filter body, prior to its contact with the gaseous mixture, containing water but in an amount not exceeding 5% by weight, and being reactivated when exhausted by heating at a temperature such that the surface layers of the body rupture to expose fresh absorbing surface but substantially none of the previously absorbed acidic gas is released, each reactivation step employed being conducted at a temperature higher than the previous one. Preferably the filter bodies consist of Ca(OH)2 and the working absorbing temperature of the filler body is between 100 DEG and 200 DEG C. and the reactivation temperature ranges in successive steps from 250 DEG to 400 DEG C. A suitable on line arrangement is depicted in the figure utilizing two filter elements 3 and 4, arranged in parallel, one 3 being in use while the other 4 is regenerated, the elements being maintained at working temperatures or reactivation temperature by heating elements 32 and 42. When detector 14 in outlet pipe 6 detects the acidic gas, i.e. CO2 breaking through element 3, controller 13 changes over two-way valve 5 and simultaneously operates switches 10 and 11 so that the heating elements 32 and 42 are connected to voltages suitable for their working or regeneration phase. Contact thermometers 33 and 43 are fitted in the heater circuit so that when the temperature of the absorbent reaches a specified upper limit, the current is cut-off. In the regeneration phase, at this temperature, the contact is not remade so the regenerated bed slowly cools. The vessel 7 is a water filter which removes water from the gas and dries it. It may be heated under the control of thermometer 72 and switch 12. Its specified operating temperature is 110 DEG C. and its specified packing is CaO + Ca(OH)2.</p> |
