Patent EA-004384-B1 (EA)
Title: Process and apparatus for isolating organic substances from gas mixtures in which these substances are present
Inventor: PRINZ PETER
IPC: C07C253/34
Filed: 2001-08-02
Abstract: 1. Process for isolating one or more organic substances from a gas mixture in which these organic substances are present, in which the gas mixture is subjected to a quenching in a column, characterized in that quenching is carried out in the upper part of the column and the quenching liquid is subjected to stripping in the lower part of the column. 2. Process according to Claim 1, characterized in that the gas mixture introduced is quenched by bringing it into intimate contact with a stream of quenching liquid and this stream of quenching liquid is subsequently subjected to stripping by bringing the quenching liquid into contact with an inert gas. 3. Process according to Claim 2, characterized in that the gas mixture introduced originates from an acrylonitrile or methacrylonitrile synthesis. 4. Process according to Claim 3, characterized in that the reaction gases formed in the acrylonitrile synthesis comprise acrylonitrile, propylene, ammonium, oxygen, nitrogen, HCN, CO2, CO, acetonitrile, acrolein, acrylic acid, fumaronitrile, nicotinonitrile, oxazole, acetic acid, water, further higher nitrites, aldehydes and ketones. 5. Process according to any one of Claims 1-3, characterized in that 0.5-8 kg, preferably 0.7-5 kg, particularly preferably 0.8-2 kg and in particular 1-2 kg, of quenching liquid, preferably water, are used per m<3> of chemically active reaction gas. 6. Process according to any one Claims 3-5, characterized in that 0.1-5 mol, preferably 0.5-3 mol and in particular 0.75-1.5 mol of inert gas are used per mol of propylene/isobutene employed in the synthesis of acrylonitrile or methacrylonitrile. 7. Process according to any one of Claims 2-6, characterized in that the inert gas used is the absorber waste gas from the absorption in the synthesis of acrylonitrile. 8. Column for carrying out the process according to any one of Claims 2-6, in which both quenching and stripping can be carried out, characterized in that a) it has an upper quenching section and a lower stripping section, b) it has a lateral feed facility for a chemically active reaction gas stream below the quenching section and, above the quenching section, a further lateral feed line for the quenching liquid, c) it has, above the quenching section, a liquid distributor through which the quenching liquid is introduced into the column, d) a feed line for the stripping gas is located below the stripping section and is arranged either above the bottom volume of the column or else at the height of the bottom volume, e) the bottom volume of the column is connected to the liquid distributor of the quenching section via a pump-driven feed line and f) optionally, part of the bottom volume can be discharged from the column via a lateral discharge line. g) a feed line for fresh quenching liquid is present at the height of the bottom volume. 9. The column according to Claim 8, characterized in that further comprises a discharge line for discharge of the product gas stream is located at the top of the column.