PROCESS FOR THE PURIFICATION OF HYDROGEN CYANIDE
FIG2 shows an embodiment of the process of the invention where first liquid stream (2) is heated by heat exchange with bottoms stream (6) before it is introduced into distillation column (4)
The examples herein are performed using a computational model of a process based on the distillation process shown in FIG2. Process modelling is an established and reliable methodology used by engineers to simulate complex chemical processes before building the real plant. In the context of the examples herein the commercial modeling software Aspen Plus® (Aspen Technology, Inc., 20 Crosby Roads, Bedford, Massachusetts 01730, USA) was used in combination with physical property data available from public databases. Using the modeling software Aspen Plus®, the purification of the acrolein comprising stream is simulated for a distillation process shown in FIG2: An aqueous feed stream (1) comprising ca. 6 wt.-% acrolein is split into a first liquid stream (2) and a second liquid stream (3) with a mass flow ratio of 85:25. The stream (2) is heated to a temperature of about 84°C in the heat exchanger (7) by use of the bottom stream (6) from the distillation column (4) to give a heated stream (8). Said stream (8) is introduced at the feed stage of the distillation column (4). The heat transmitted in the heat exchanger (7) is kept at 9765 kW for all mass ratios of stream (2) to stream (3). The thus obtained cooled bottom stream (11) is discarded. The stream (3) is introduced at the highest stage of the distillation column (4) with a temperature of 18.5°C. A bottom stream (11) enriched in water is feed to the heat exchanger (7).
embodiment
3
stream
2
stream streams
10
stream
13
liquefied stream
['1. A process for the purification of hydrogen cyanide, comprising the steps of a) splitting a liquid feed stream (1) comprising hydrogen cyanide into at least a first liquid stream (2) and a second liquid stream (3), b) introducing the first liquid stream (2) with a temperature T1 into a distillation column (4) at a point between the top and the bottom of the distillation column, c) introducing the second liquid stream (3) with a temperature T2 into the distillation column (4) at the top of the distillation column (4), d) withdrawing an overhead vapor stream (5) enriched in hydrogen cyanide from the distillation column (4), and e) withdrawing a bottom stream (6) depleted in hydrogen cyanide from the distillation column (4), wherein the temperature T2 of the second liquid stream (3) in step c) is lower than the temperature T1 of the first liquid stream (2) in step b).', '13. The process according to any of claims 1 to 10, further comprising the steps of g) condensing at least a part of the overhead vapor stream (5) withdrawn from the distillation column (4) to give a liquefied stream (13) and, if applicable, a residual vapor stream (14), and h) feeding the liquefied stream (13) of step g) to a further processing or to a storage tank.']