公开(公告)号：US20230234859A1

公开(公告)日：2023-07-27

申请号：US17996954

申请日：2021-04-24

申请人： Covestro Deutschland AG

发明人： Thomas Rosin ,  Peter Drinda ,  Klaus Pilarczyk

IPC分类号： C02F1/00 ,  B01D3/34 ,  B01D3/38 ,  B01D3/42 ,  C02F1/10 ,  B01D3/26

CPC分类号： C02F1/008 ,  B01D3/346 ,  B01D3/38 ,  B01D3/42 ,  C02F1/10 ,  B01D3/26 ,  C02F2101/38

摘要： The present invention relates to a process for purifying a wastewater stream WW1 contaminated with nitrobenzene, comprising (I) stripping of the wastewater stream WW1 with a stripping gas SG1 in a continuously operated stripping column to obtain a wastewater stream WW2 which contains nitrobenzene in a concentration reduced relative to WW1 (cNB,WW2), (II) further purification of the wastewater stream WW2 in a wastewater treatment plant, wherein a target value (cNB,WW2,TARGET) is specified for the concentration of nitrobenzene in the wastewater stream WW2, which is greater than zero but takes into account the requirements of the wastewater treatment plant for the maximum content of nitrobenzene in the wastewater streams supplied thereto, wherein, for at least one combination of specified boundary conditions of (a) nitrobenzene concentration in WW1, (b) the temperature of WW1, and (c) the temperature of SG1, a set of linear mathematical relationships of the type mSG1=x·mWW1 is stored in a database, which linear mathematical relationships define a range of concentrations of nitrobenzene in WW2, wherein the set comprises, in addition to a mathematical relationship (0) which corresponds to the target value cNB,WW2,TARGET, at least a first mathematical relationship (1) for a first value of cNB,WW2, which corresponds to 98% of the target value cNB,WW2,TARGET, and a second linear mathematical relationship (2) for a second value of cNB,WW2, which corresponds to 102% of the target value cNB,WW2,TARGET, and wherein the flow rate of the stripping gas is adapted to the flow rate of the wastewater WW1 such that the flow rate of WW1 is within a range of values (AB) that is generated by the first mathematical relationship (1) and the second mathematical relationship (2) at the respective flow rate of WW1, and controlling the concentration of nitrobenzene in WW2 (cNB,WW2) by adjusting the flow rate of stripping gas SG1 accordingly in the event of a measured actual value of this concentration which is outside a window of >98% to

公开(公告)号：US12129187B2

公开(公告)日：2024-10-29

申请号：US17996954

申请日：2021-04-24

申请人： Covestro Deutschland AG

发明人： Thomas Rosin ,  Peter Drinda ,  Klaus Pilarczyk

IPC分类号： C02F1/10 ,  B01D3/26 ,  B01D3/34 ,  B01D3/38 ,  B01D3/42 ,  C02F1/00 ,  C02F101/38

CPC分类号： C02F1/008 ,  B01D3/26 ,  B01D3/346 ,  B01D3/38 ,  B01D3/42 ,  C02F1/10 ,  C02F2101/38

摘要： A process for purifying nitrobenzene-contaminated wastewater stream WW1 includes stripping WW1 with stripping gas SG1 in a stripping column to obtain wastewater stream WW2 containing reduced concentration of nitrobenzene relative to WW1 (cNB,WW2), and purifying WW2 in a wastewater treatment plant, wherein a target value (cNB,WW2,TARGET) is specified for the nitrobenzene concentration in WW2. A set of linear mathematical relationships is stored in a database for a combination of boundary conditions of nitrobenzene concentration in WW1, temperature of WW1, and temperature of SG1. This set defines a range of concentrations of nitrobenzene in WW2 and includes a mathematical relationship corresponding to cNB,WW2,TARGET, a mathematical relationship for a value of cNB,WW2 corresponding to 98% of cNB,WW2,TARGET, and a linear mathematical relationship for a value of cNB,WW2 corresponding to 102% of cNB,WW2,TARGET. The concentration of nitrobenzene is controlled in WW2 (cNB,WW2) by adjusting the flow rate of SG1.