method and device for synthesedruk back to win of ammonia and carbon dioxide from the spuigas a ureumsynthese.

摘要

1341100 Removal of NH 3 VCO 2 from tail gas STAMICARBON NV 24 May 1971 [30 May 1970] 16579/71 Heading C1A [Also in Divisions C2 and B1] In a process for the removal of NH 3 and CO 2 from urea synthesis tail gas, the gases are washed with an aqueous absorbent to remove NH 3 and CO 2 and the residual gases are then diluted by the introduction of a diluent gas to form a gasious mixture of reduced explosive character. In the drawing gas from urea synthesis autoclave (not illustrated) passes into a wash column D through line 7 and inlet 9 into the bottom part of said column which is constructed as a gas bubble washer and is cooled by cooling elements (not illustrated). Gases having this washer then pass through a packed bed 11, e.g. of Rasching rings, in countercurrent flow to a stream of wash liquid supplied from line 12 and device 13. The gas leaving this fixed bed is substantially free of NH 3 or CO 2 is immediately mixed with an inert gas, e.g. air, N 3 or CO 2 , supplied via line 14 and distribution device 15 before being vented through 16. The wash liquor from the packed bed 11 flows down into the bottom of column D to supply the gas bubble washer, excess liquor from which is removed via overflow funnel 10 and line 8. In a further embodiment of the apparatus (Fig. 4, not illustrated) the diluent gas is also supplied to a buffer zone surrounding and connected to the gas space above the absorption vessel such that in the event of an explosion occurring the buffer zone will be able to absorb the increased pressure.