Sulfuric acid recovery process SARP

The sulfuric acid recovery process (SARP), developed jointly by Texaco Inc. and Stratford Engineering Corp. to reduce the acid consumption in H2S04 alkylation units, was another contribution to alkylation technology (18). In this process the spent acid from an alkylation... 

One patented process (40) was introduced in the mid- 60s to reduce the amount of sulfuric acid required by alkylation it was called the Sulfuric Acid Recovery Process (SARP) and was jointly licensed by Texaco Development Corporation and Stratford Engineering Corporation. Chemically, SARP proved all claims made for it. Utilized only with propylene/butylene alkylation the acid requirement was reduced as much as 70% actual acid dilution rates were lower than 0. 2 acid/gallon alkylate. However, the spent acid from SARP was different and could not be regenerated at the same rate as regular spent alkylation acid. This caused the chemical companies to increase the charges for regenerating the SARP spent acid to a point where there was no economic incentive to operate SARP. The two commercial SARP installations are not in use at the present time although new possibilities for SARP have arisen just in the past few months. 

A number of different processes involving the absorption of olefin in recycle sulfuric acid alkylation catalyst, extraction of the dialkyl sulfate, treatment of the extract in some manner, and alkylation of the treated dialkyl sulfate have been considered. One such process which has become known in the industry as SARP is the subject of this paper. SARP stands for Sulfuric Acid Recovery Process, which obviously has a rather generic connotation. The process is rather specific. The writer prefers the name originally given to the process, namely, Extractylation. However, SARP has the advantage of being known and is short, so SARP will probably prevail. 

SARP [Sulfuric Acid Recovery Process] A method for recovering sulfuric acid that has been used for alkylation, for reuse. The acid is reacted with propylene, yielding dipropyl sulfate, which is extracted from the acid tar with isobutane. It is not necessary to hydrolyze the sulfate to sulfuric acid because the sulfate itself... 

A process termed SARP has been developed for the recovery of the used or discarded catalyst from the alkylation of isobutane with olefins using strong sulfuric acid as the catalyst. The process was used commercially for several years by two companies, but currently is not in commercial operation. 

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