【Chemical Industry News – Alkylation】Recent advances in alkylation technology in recent years

Thread Content

This post was last edited by Xiao Gong 1985 on 2016-6-9 08:01. According to a report in the American journal Chemical Engineering from May 2016, alkylation is an increasingly important refining technique; it involves the reaction of low-carbon olefins with isobutane to produce trimethylpentane isomers, namely alkylated oils, which can be used as components in the formulation of clean gasoline. Alkylated oil is a high-quality component for gasoline, featuring a high octane rating, low vapor pressure, low sulfur content, and no aromatics. The demand for alkylated oils is on the rise, primarily due to economic growth which requires more gasoline, **the enforcement of stricter gasoline standards that call for a reduction in the content of high-octane components such as aromatics and olefins in blended gasoline, as well as the need for high-performance engines. Strict limits on the sulfur content in gasoline require more intensive hydrogenation processes, which results in a decrease in the octane rating of gasoline. Alkylated oil is a high-octane, low-sulfur blending component that can increase the octane rating of the final gasoline. Another factor is the availability of cheap butane in U.S. shale deposits, which provides an abundance of inexpensive raw materials for alkylation. Advances in solid acid catalyst alkylation technology over the past few months have shown that solid acid alkylation catalysts, which have been under development for many years, are now capable of replacing harmful and corrosive liquid acid catalysts (hydrofluoric acid and sulfuric acid). At this year’s AFPM conference, CB&I presented progress on the world’s first industrial-scale alkylation plant using solid acid catalysts. This plant is located at Zibo Haiyi Fine Chemicals, a subsidiary of Hui Feng Petrochemicals in Shandong, China, and it began operations in August 2015. The facility utilizes the AlkyClean technology developed through a collaboration between CB&I, Yabao, and the Finnish company Neste, with an alkylation oil production capacity of 2,700 barrels per day (100,000 tons per year). CB&I Company states that so far, all the performance parameters of the facility built in Shandong have met the expected levels. Since its production, the quality of the alkylated oil products has been proven to be excellent; their research octane number (RON) ranges from 96 to 98, which is significantly higher than that of conventional alkylated oils. Studying the octane number is an important indicator of the value of alkylated oils as components in gasoline blending. The AlkyClean technology uses the AlkyStar catalyst developed by Avon, which is a durable fixed-bed zeolite catalyst. When combined with CB&I’s innovative reactor design, this catalyst enables the AlkyClean process to produce high-quality alkylated oil products without the use of liquid acid catalysts, making the process safer and more reliable. It is a very effective technique for producing alkylated oils, as it requires no post-treatment and generates no acid-soluble oil waste. In February of this year, KBR announced that the first technology transfer contract for its K-SAAT solid acid alkylation technology had been signed. It is Dongying Haikelerlin Chemical Company that has signed a contract with KBR to build production facilities in Dongying City. KBR provides proprietary technologies, basic process design, key equipment, and catalysts. It is expected that this installation will come online in the first quarter of 2017. The K-SAAT process is characterized by the use of a solid acid catalyst called ExSact. This is an improved zeolite catalyst that is now available commercially; compared to liquid acid catalysts, it poses much less harm to humans and the environment. This advantage, along with lower capital investment, are the main factors that influenced Haike Company’s decision to choose the K-SAAT process over conventional sulfate alkylation technology. Gautham Krishnaiah, Technical Manager for Catalytic Cracking and Alkylation at KBR, said that solid acid catalyst alkylation units also incur lower operating costs, as they require less maintenance compared to K-SAAT units, and there is no need for refrigeration in sulfuric acid alkylation units. Furthermore, neither liquid acid regeneration nor solid waste treatment (acid-base neutralization) is required. KBR developed this green chemical technology in collaboration with Exelus, and now KBR is the sole licensor of Exelus’ ExSact catalyst. The K-SAAT process uses two reactors: one for alkylation operations and the other for regeneration or as a backup. Hydrogen is used to fully regenerate the catalyst; during this regeneration process, soft coke (various highly unsaturated hydrocarbons) and contaminants adsorbed on the catalyst are removed and blown away. The successfully developed ExSact catalyst outperforms liquid acid catalysts and other solid acid catalysts in many aspects. To enhance product selectivity, both the acid sites and pore structure of the catalyst were optimized. Compared to other solid acid catalysts, the operation cycle for alkylation using the ExSact catalyst is longer ； There is great flexibility in the source of raw materials and their components (ethylene, propylene, butylene, and pentene can all be used as olefins). In contrast, the liquid acid alkylation process cannot be used with ethylene for alkylation, as the use of ethylene results in the formation of stable esters. Furthermore, KBR’s solid acid process has excellent resistance to contaminants in the feedstock, such as moisture, sulfur, dienes, oxygen-containing compounds, and nitriles. Advances in sulfate catalyst alkylation technology: The emergence of industrial-scale solid acid alkylation processes has not prevented the innovative use of liquid acid catalyst alkylation units. DuPont is applying its sulfate alkylation technology to some unique raw materials. In March of this year, DuPont announced that it had signed a contract with a Chinese refinery to supply an alkylation unit that uses 100% butylene as raw material. Jeannie Branzaru, Global Sales Manager for Clean Technology at DuPont, said that the chemical foundation for DuPont’s new alanation technologies has been in place for a long time, and current economic conditions are favorable for using butane to produce alkylation oils, or what is known as \"specialty alkylation\" technology. This unique processing method was not economical in the past. Branzaru said that many companies can purchase low-value butane cheaply on the open market, process it in dehydrogenation units to produce isobutylene, and then feed that isobutylene into alkylation units to manufacture high-value alkylated oils. However, DuPont’s technology is not limited to butane; it can also process very high concentrations of propylene and 100% pentene. Dalian Hengli Petrochemical Company in China has signed a contract with DuPont to supply alkylation and spent acid regeneration (SAR) technologies for the construction of production facilities at the new refinery in the Changxing Island Port Industrial Zone. At present, Hengli Petrochemical Company plans to start construction in 2018, with operation expected to begin in 2019. DuPont will use its own Stratco alkylation and MECS spent acid regeneration technologies. By adopting DuPont’s technology in its integrated refining and chemical complex, Hengli Company will be able to produce high-quality alkylate products using 100% isobutylene as raw material. Kevin Bockwinkel, Global Business Manager for Stratco Technologies at DuPont, said, “Hengli’s facility has access to unique raw materials, marking the beginning of a new era for alkylated oils in the gasoline market, as facilities for producing alkylated oils from butane are increasing around the world.” Hengli Company’s alkylation unit will utilize DuPont’s XP2 patented technology in the Stratco contact reactor. Bockwinkel stated that the design of XP2 technology ensures very efficient utilization of the heat transfer surfaces in the tube bundle, thereby improving the quality of alkylated oil products through significant process advantages.