Selective Adsorption for Deep Desulfurization at Ambient Temperature

2 Selective Adsorption for Deep Desulfurization at Ambient Temperature 

More recently, Yang and coworkers have reported on adsorption separation of thiophenic sulfur compounds from aromatic compounds based on rt-complexation using Cu- and Ag-exchanged Y zeolites. The Cu(I)-Y zeolite was prepared by reducing the Cu(ll)-Y zeolite at 450°C in He atmosphere. Better adsorption performance was noticed over Cu(I)-Y zeolites. 

However, it is not clear how the 7i-complexation can differentiate between sulfur-containing aromatic compounds and non-sulfur containing aromatic compounds in real liquid fuels, although they have shown by theoritical calculations that the Ti-complexation strength is higher for thiophene compared to benzene. The authors have noted that the adsorption performance of the Cu(I)-Y zeolite is decreased when aromatics are present in the fliel probably due to the competitive adsorption of sulfur compounds and aromatics by Ti-complexation. 

3 New Integrated Process Concept Based on Selective Adsorption 

The PSU-SARS-HDSCS concept represents an attempt to make deep desulfurization in a future refinery fundamentally more efficient and consumes less hydrogen, which is a significant cost factor for both capital investment (H2S scrubber for recycle H2 gas, compressor) and process operation (consumption of H2). It is known that for current commercial hydrotreater operations, each 1 wt% sulfur removal results in about 18-20 NmVm feed (110-120 SCFB) of H2 consumption each 1000 ppm nitrogen removal results in about 5.9-6.1 Nm /m (35-36 SCFB) of H2 consumption each 1 wt% aromatics removal yields about 5.0-8.4 (use half of these numbers if aromatics are reported as voliune %) each one unit increase in °API gravity requires about 17 NmVm feed (100 SCFB) of H2 consumption, as does each one imit increase in cetane number for diesel stocks . 

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