UOP Alkylene Process

Fig. 15. UOP Alkylene solid acid-catalyzed alkylation process (237).

Technologically, the Alkylene process is a break-through. Several significant inventions were required to make it technically feasible. The development of a unique solid-acid catalyst and transport reactor by UOP allows for the potential elimination of hazardous liquid acid processes. About 1 MM gallons of hydrofluoric acid inventory could be eliminated, transport of 33 MM lbs (4 MM gallons) of hydrofluoric acid per year would be stopped, and ca. 20 MM lbs per year of other fluoride containing solids would not have to be land filled. 

Note, however, that liquid acids are still largely used in refinery and petrochemical processes. For example, HF alkylation (for isobutane alkylation with light olefins) is still among the top-ten refining processes licensed by UOP, with over 100 units installed worldwide. However, UOP introduced from 2002 the Alkylene process, which uses a liquid phase riser reactor with a solid acid catalyst for the isobutane alkylation. However, HF alkylation remains the best economic choice [223], notwithstanding environmental and corrosion problems. Also in this case, the conventional process has been improved, for example by HF aerosol vapor suppression. Other aspects of isobutane alkylation have been reviewed by Hommeltoft [224]. 

The Alkylene process employs a catalyst referred to as HAL-100, whose composition has not been disclosed. It is likely that the catalyst is an AI2O3-supported AICI3 promoted by and alkaline or alkaline earth metal cation and a hydrogenating function due to a transition metal such as Ni, Pd, or Pt, as it is reported in the UOP s patent where the process is described (248). During the reaction, a makeup of a halide source such as an alkyl chloride or hydrogen chloride has probably to be fed to the reactor to keep the catalyst activity at the desired level (249). 

According to UOP sources, the alkylate product obtained by the Alkylene process displays values of RON = 95 and MON = 93 (250). In 2005, Baku Heydar Aliyev Refinery (BHAR, Azerbaijan Republic) chose UOPs Alkylene technology... 

Given the obvious disadvantages of the existing alkylation processes several alternative catalyst technologies have been proposed and tested but are not yet at the same mature commercial level. Solid acid catalysts (Lummus Technology - Alky-Clean , Exelus - ExSact , and UOP - Alkylene ) or acidic ionic liquid catalysts (PetroChina - lonikylation ) show a lot of promise but their economics have to compete in many cases with old, fully depreciated existing plants, which prevents rapid market penetration. 

During the last 40 years, an enormous effort was put into searching for a solid catalyst [4, 5]. The main obstacle still to be overcome is the formation of acid-soluble oils (ASO, also known as conjunct polymers or red oil) which accompanies the alkylation process. This material contains highly unsaturated cyclic hydrocarbons, which rapidly passivate the catalyst. When liquid catalysts are used, they can be easily withdrawn from the process and replaced, without interrupting the alkylation operation. UOP has developed the Alkylene technology, which uses the proprietary HAL 100 catalyst in a process that is claimed to be commercially competitive [6]. 

Alkylene A process for making alkylate (see previous two entries) by reacting olefins with isobutene, using a proprietary solid acid catalyst called HAL-100. The major constituents of this alkylate are branched trimethylpentanes. Developed by UOP from 1995. 

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