Benzene → Cumene

The benzene column 140 receives feed from the bottoms of the depropanizer column 130 in the line 136 after it is mixed with transalkylation effluent in a line 152. The benzene column 140 produces a benzene column overhead stream comprising benzene in a line 142 and a benzene column bottom stream comprising ethylbenzene and PEBs in a line 144. The overhead benzene stream in the line 142 may be provided with a water concentration of about 50 to about 150 wppm and a temperature of at least about 120° C. and preferably greater than 125° C. and no more than about 170° C. The depropanizer intermediate stream in the line 132 has similar properties, and is combined with stream 142 and delivered to a hot adsorbent vessel 160 by line 161. The hot adsorbent vessel 160 contains a bed of acidic molecular sieve adsorbent for the removal of ONCs, including nitrites from the mixed benzene stream in the line 161. The denitrogenated benzene effluent in a line 164 is delivered to both the alkylation reactor 120 by the line 102 and to a transalkylation reactor 150 by a line 166. The benzene stream in the line 166 is mixed with an intermediate stream comprising diisopropylbenzene (DIB) in a line 168 from a heavies column 190. The mixture of benzene and DIB in a line 154 are delivered to the transalkylation reactor 150. The DIB transalkylates with benzene over a transalkylation catalyst bed 156 in the transalkylation reactor 150 to produce cumene. Transalkylation effluent in the line 152 has a greater concentration of cumene and a smaller concentration of benzene and DIB than in the line 154.