Sulfuric acid alkylation technology

Over the years H2S04 alkylation capacity has declined relative to HF alkylation.303,304 Reasons for this trend are a significantly lower acid consumption, overall lower operation costs, and less expensive regeneration plant cost and operating expenses of the HF alkylation process. Because of the mentioned environmental hazard associated with anhydrous HF and the need for further improvement of alkylate quality, improved technologies for sulfuric acid alkylation emerged, although it is improbable that there will be a major turnback to sulfuric acid alkylation. 

Many petrochemical companies hold extensive patent portfolios relating to ionic liquid technologies. However, the first of these to announce an industrial process is PetroChina. The process for alkylation of isobutene uses an alumi-nium(iii) chloride based ionic liquid and is called lonikylation. After success at the pilot plant stage, the technology is currently being retrofitted into an existing sulfuric acid alkylation plant in China with an output of 65 000 tonnes per year. This retrofit will increase yield and capacity at the site and is the largest commercial use of ionic liquids reported to date. ... 

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... 

In 1999, Akzo Nobel (which later sold its catalyst division to Albemarle) patented a new technology for alkylating hydrocarbons based on a zeolite acid catalyst [193]. This new process, AlkyClean, was then designed by ABB Lummus and Albemarle, and a 10 barrels per stream day (BPSD) demonstration unit came online in Finland in 2002. AlkyClean produces a high-quality sulfur-free alkylate (96 octane), eliminating all the drawbacks of the liquid acid catalyst technologies. There are no add-soluble oil waste streams, the reactor operates at 50-90 °C, and the catalyst is a solid, noncorrosive material, which is easily transported and stored. 

The main requirement to methylchloride, ethylchloride and chlorobenzene is the absence of impurities, by-products and especially moisture. With even the slightest amount of liquid entering the reaction zone, the products start to hydrolyse and condense, the activity of the contact mass or copper-silicon alloy decreases, and the process subsides. That is why the technology of direct synthesis usually provides for a device to dehydrate alkyl- and arylchlorides. For this purpose one can pass methyl- or ethylchloride through the tower sprayed with sulfuric acid, or use other dehydrating substances (burnt CaCF, AI203 and zeolites, e.g. burnt klinoptilo-lite). 

III. Discussion of the basic principles of current sulfuric acid and HF alkylation technology and of any likely developments which could lead to a change m the present balance between the two. 

Bronsted Acids. Sulfuric acid (H2SO4) is an inexpensive, easy to handle protic acid used widely as catalyst in hydrolysis, hydration and dehydration, elimination, substitution, and rearrangements. It also catalyzes aromatic electrophilic substitutions mostly Friedel-Crafts acylations and alkylations (22). A very important application of sulfuric acid is its use in commercial isoalkane-alkene alkylation technologies. These commercial processes are still based on the use of sulfuric acid (and hydrogen fluoride) catalysts (23). 

Ammonium salts of alkenyl succinic half-amides have teen described for use as corrosion inhibitors in oil and gas production technology to combat corrosion by media containing CO2, H2S, and elemental sulfur [1366]. The inhibitor composition may contain a dispersing agent, such as a low molecular weight or polymeric anionic surfactant like an alkylsulfonic acid or an alkyl-aryl sulfonic acid. 

---