| 摘要 |
<p>1,241,065. Separating gas mixtures. UNION CARBIDE CORP. 9 Aug., 1968 [9 Aug., 1967], No. 38163/68. Heading B1L. A four bed adiabatic pressure swing bed cyclic process for separating gas mixtures by adsorption comprises taking each of the four beds in turn and in the appropriate time relationship through the sequence of steps shown. Thus, feed is passed by manifold 10 to bed A where impurities are adsorbed and product effluent leaves by manifould 11. Adsorption is discontinued before impurity breakthrough occurs, whereupon feed is switched to bed D, and thereafter in turn to beds B and C before bed A comes on-stream again in the next cycle. After adsorption in bed A has been discontinued, the pressure of bed A is equalized with that of bed B (which is being repressurized prior to coming on-stream) through the discharge end of bed B. Thereafter, bed A is cocurrently depressurized by connecting its discharge end to the discharge end of bed C, thereby purging bed C prior to repressurization of residual sorbate through manifold 12. Bed A is then countercurrently depressurized through its inlet end to desorb and remove sorbate through manifold 12 and afterwards purged by introducing gas from the countercurrent depressurization step of bed D to its discharge end. Bed A is then repressurized partly with gas from the pressure equalization step of bed B, and partly by the recycling of a portion of the product effluent. As described, the process is of particular application to the removal of light hydrocarbons, carbon monoxide and dioxide, ammonia, hydrogen sulphide, argon, nitrogen and water from gas streams consisting principally of hydrogen, but is also of value in separating nitrogen or helium from minor amounts of impurities. A flow sheet is provided (see Fig. 1, not shown) setting out details of the various valves and interconnections necessary. In one example, the beds are each constituted of a first section of active carbon and a second section of calcium zeolite A. The process may also be adapted for use with five beds (see Fig. 3). Reference has been directed by the Comptroller to Specification 1,067,177 and 989,073.</p> |
