Development And Application Of Adsorbents For Benzene And Propylene Purification In Cumene Unit

In cumene unit,the basic nitrogen and sulfur impurities in benzene and propylene feed can deactivate the acidic catalyst,thus shortening the span life of the catalyst.Therefore,it is vital to clean the benzene and propylene feed during the purification unit of the reaction system in order to protect the catalyst activity.Purification process of the feeds are through two stage protective beds in cumene unit,the first bed is used to remove alkaline nitrides and sulfides from benzene and the second bed is designed for adsorbing weakly alkaline nitrides and sulfides.The first bed for propylene is designed to remove the impurities such as sulfur and arsenic in propylene,and the second bed for propylene is designed to remove polar compounds such as nitrogen and water.In this paper,the adsorbents for benzene purification and the adsorbent for propylene purification have been developed and applied to benzene bed and propylene bed of the 167 KTA cumene plant in Gaoqiao Petrochemical Company.The result of research:It was feasible that recycled BTA instead of clay for the first bed for benzene.Compared to acid clay,the total acid content and nitrogen capacity are higher.The adsorbentRX-15for the second bed for benzene can effectively remove weakly alkaline nitrides in benzene and the total nitrides content is lower than 0.03mg/kg after purification,which meets the technological requirements.RX-15 has a longer life span and decreases the frequencies of replacement of adsorbents.The multiple metal oxide adsorbent ADX-12 has been developed and applied to the first bed for propylene.ADX-12 has a large specific surface area,high pore volume,high sulfur capacity.The sulfur content in propylene is lowerthan0.1 mg/kg after ADX-12 purification,which meets the requirements of plant.ADX-12 has high sulfur capacity which extend the life span of adsorbent.