MTBE and ETBE

This post was last edited by 18 on 2009-5-27 at 13:05. I. Concepts and Terminology Explanations 1. ETBE (Ethyl Tertiary Butyl Ether): Ethyl tert-butyl ether is a high-octane gasoline blending component with excellent properties. ETBE, ethanol, and MTBE are all high-octane gasoline modifiers, also known as “biofuel additives”. The maximum addition level of ETBE in gasoline is 17 Vol%. ETBE not only improves the octane rating of gasoline but can also be used as a co-solvent. ETBE has a high boiling point and does not form azeotropic compounds when mixed with hydrocarbons. This not only reduces air resistance inside the engine but also lowers evaporation losses. ETBE can also be decomposed by aerobic microorganisms. Therefore, ETBE not only enables the octane rating of gasoline to be increased, but also improves its economic efficiency and safety; thus, it is an excellent additive with great market potential. The raw materials for the synthesis of ETBE are ethanol (EtOH) at 47% and isobutylene (IB) at 53%. That is: BIO Ethanol (EtOH) mixed with Water (H2O) at a concentration of 92–95% by volume) + IB (Isobutene). 2. Biological ETBE mixture: After introducing ETBE in general terms, the ETBE mentioned here is provided by the Japanese company IBF; we refer to it as a biological ETBE mixture. It is a \"mixture of ETBE, TBA (butyl ethyl acrylate), and EtOH (ethanol)\」produced through a series of processes using aqueous bioethanol (92–95 vol%) and isobutylene (C4H8); it is a clean high-octane gasoline modifier. After 13 years of research and development, Nippon Kabushiki Kaisha IBF has overcome the future challenges associated with ethanol-based gasoline, and developed a \"biological ETBE mixture production technology\" that is more competitive than the ETBE produced by manufacturers in Europe and the United States. The production technology for this product has been subject to patent applications by Nippon Kabushiki Kaisha IBF in Japan and South Korea (patent application number: 2004-327533), and applications for patents in our country are also underway. Biological ETBE mixtures are produced through a low-temperature and low-pressure process, using plant residues and waste fermentation products from the production of biological ethanol, as well as methane from distillation liquids as raw materials. 3. With its advanced \"biological ETBE mixture production technology,\" IBF Corporation in Japan is developing an experimental plant for biological ETBE II made from 100% biological raw materials, aiming to achieve high productivity while seeking effective measures to address the greenhouse effect. Including gasoline, the fuel used to power cars is currently obtained from underground resources. ETBEII produces ETBE mixtures entirely from biological raw materials, making it excellent in terms of resource recycling and addressing the greenhouse effect. (Converting isobutylene from petrochemical fuels to ones derived from biological sources). II. Comparison of MTBE, ETBE, and fuel ethanol. Octane number improvers (additives) are an aspect of high-octane gasoline technology. There are three legally approved gasoline additives in the United States, namely: a) MTBE (methyl tert-butyl ether), b) ethanol (EtOH), and c) ETBE (ethyl tert-butyl ether). ETBE, ethanol, and MTBE are all gasoline modifiers or additives of this kind. Mixing them into gasoline in a certain proportion can not only improve the performance of gasoline but also be environmentally friendly. (Pb-free, pollution-free). (1) MTBE (Methyl Tertiary Butyl Ether): Methyl tert-butyl ether – The maximum amount that can be added is 15 Vol%. MTBE is an aliphatic ether with the molecular formula C5H12O, a molecular weight of 88.14, a specific gravity of 0.741 at 20°C, and a viscosity of 0.27 at 20°C; it has an ether-like odor. Methyl tert-butyl ether (MTBE) is the earliest developed and used ether-based octane booster. Since the U.S. Environmental Protection Agency approved MTBE for use as an additive in lead-free gasoline in 1979, it has been widely used in gasoline blending in the United States. MTBE has a relatively low boiling point; adding it to gasoline lowers the boiling range of the gasoline. This effect brings significant economic benefits to refineries that produce ultra-high octane gasoline. MTBE (methyl tert-butyl ether) is currently widely used; due to the difficulties involved in its production, many countries, including my own, rely on imports. In recent years, scientific research has revealed the disadvantages of MTBE: it is not easily decomposed and can cause pollution to groundwater ； It has a slight odor that can cause discomfort to the driver, leading to symptoms such as nausea, eye pain, and blisters. The United States has recently passed a \"Clean Fuel Act\" that will ban MTBE over the next 4 years. The majority of ethanol growth in Europe is expected to come in the form of ethyl tert-butyl ether (ETBE). (2) Ethanol (EtOH): Alcohol – The maximum amount that can be added is 10 Vol%. Its scientific name is ethanol; its chemical formula is C2H6O (CH3–CH2–OH), with a molecular weight of 46. Ethanol is both a basic raw material in the chemical industry and a new energy source. In the future, the market direction of ethanol as an industrial commodity will be reflected mainly in three areas: first, as a fuel for vehicles, primarily in the form of ethanol-blended gasoline and ethanol-blended diesel. This is what we traditionally refer to as the fuel ethanol market. Fuel ethanol is added to gasoline in a certain proportion; it is not used simply as a substitute fuel, but rather as an excellent agent for improving the quality of gasoline, or in other words, as an oxygenator. It is also a high-octane blending component for gasoline. Ethanol is better than MTBE in terms of oxygenation effects as well as environmental protection. Therefore, China did not pursue the MTBE route from the start, but instead adopted the production and promotion of ethanol additives right away. (3) ETBE (Ethyl Tertiary Butyl Ether): Ethyl tert-butyl ether – the maximum amount that can be added is 17 Vol%; it is made by mixing 47% ethanol with 53% isobutylene. Similar to MTBE, adding ethyl tert-butyl ether to gasoline is equivalent to adding ethanol to it. ETBE is not only more effective than MTBE in increasing gasoline octane number, but it can also be used as a co-solvent. ETBE has a high boiling point and does not form azeotropes when mixed with hydrocarbons. This reduces both the aerodynamic resistance inside the engine and the evaporation losses. ETBE can be broken down by aerobic microorganisms, but MTBE cannot. ETBE not only improves the octane rating of gasoline, but also makes it more economical and safer compared to gasoline with MTBE added, thus it holds great market potential. Comparison conclusion: A. Compared to MTBE, ETBE not only improves the octane rating of gasoline but can also be used as a co-solvent. Moreover, it improves both the economy and safety of gasoline compared to gasoline with MTBE added. B. ETBE has a higher boiling point and does not form azeotropic compounds when mixed with hydrocarbons. This reduces both the aerodynamic resistance inside the engine and the evaporation losses. C. The distillation range of ETBE and isooctane is narrow, which can improve the drivability index ； DI) and the control of VOCs (volatile organic compounds) during mixing. D. ETBE has a higher octane rating, a lower Raoult vapor pressure, and less water solubility than MTBE; therefore, it is more suitable as an oxygenate additive for gasoline than ethanol, and thus ETBE holds great market potential. III. Current Status of ETBE Synthesis Technology As MTBE is gradually being banned, research on ETBE has received increasing attention. Currently, ether synthesis technologies abroad are highly advanced, with MTBE, TAME, and ETBE all being produced on an industrial scale. In China, only MTBE is produced on an industrial scale domestically; the TAME synthesis technology is in the stage of industrial implementation, while the ETBE synthesis technology is still in the research phase. ETBE is generally produced by reacting isobutylene in mixed C4 with ethanol in the presence of an acidic catalyst; this is an exothermic reaction, and in industrial production large-pore sulfuric acid-type ion exchange resins are predominantly used as catalysts. The side reactions are mainly the dimerization and hydration of ethylbutene. In terms of reactor configuration, ETBE production technologies can be divided into fixed-bed technology and catalytic distillation technology. The fixed-bed technology is simple in equipment and easy to operate, but the isobutylene conversion rate is limited by thermodynamic equilibrium, reaching a maximum of only 92% (under high temperature and pressure), and the reaction heat cannot be utilized. Catalytic distillation technology disrupts the thermodynamic equilibrium of the reaction, enabling an isobutylene conversion rate of over 99.5%. The etherified C4 contains almost no isobutylene, and can be used to produce basic chemical raw materials such as 1-butene and butadiene. Moreover, the reaction heat is utilized for product separation, thereby reducing energy consumption. Therefore, the technology for synthesizing ETBE via catalytic distillation is more competitive in industrial production, and the key to this technology lies in the method of loading the catalyst in the catalytic distillation column. Catalytic distillation technology represents the future direction for ETBE production. Additionally, ethanol recovery technology is an important component of ETBE production processes. Currently, the technology of using pervaporation membrane separation for ethanol recovery has low energy consumption and holds promising prospects. Currently, the production technology for ETBE abroad is highly mature. The main companies around the world that possess this technology include the French Institute of Petroleum (IFP), CDTECH in the United States, ARCO Chemicals, UOP, and Phillips Petroleum. There are not many institutions in China that research ETBE production technology.

Our company produces MTBE, and I am also interested in the development of ETBE.

The United States is accelerating the ban on MTBE. As an octane booster for gasoline, MTBE (methyl tert-butyl ether) not only increases the oxygen content in gasoline but also promotes cleaner combustion and reduces harmful emissions from vehicles. However, MTBE is highly soluble in water. Due to leaks from underground and above-ground gasoline tanks, the United States has found increasing amounts of MTBE in underground drinking water sources. Even at low concentrations, MTBE can cause unpleasant odors in water quality, and the U.S. Environmental Protection Agency has listed MTBE as a possible carcinogen. By 2006, however, the global annual production capacity for MTBE was still around 21 million tons. With growing calls in the United States to ban MTBE, the survival of MTBE production facilities faced severe challenges. The United States is accelerating the ban on MTBE. Due to its impact on water quality, California banned MTBE in 2004, while states such as Arizona, Connecticut, and New York also prohibited it starting in 2005. Since 2006, the pace of banning MTBE in gasoline in the United States has accelerated further. As of April 2007, 26 states in the United States had banned MTBE. Analysts suggest that the United States may ban MTBE completely in 2008. As bans expanded, U.S. MTBE usage declined from slightly over 12.88 million tons in 2004 to 7.29 million tons per year at present. Since 2006, MTBE production in the United States has been on a downward trend, with several major producers ceasing its manufacture; among the large producers, only Huntsman continues to produce it. In addition, there are some small producers that continue to produce MTBE to meet export demands. Europe** countries such as Spain, France, Germany, and Italy also show similar trends; incentives for renewable fuels have accelerated the shift in Europe from using MTBE to ETBE (ethyl tert-butyl ether) in manufacturing processes. Experts predict that European ETBE production will increase from 2 million tons in 2006 to over 5 million tons by 2008. There are various alternatives to MTBE. In addition to increasing ethanol production as a substitute for MTBE, developed countries have also developed other alternatives, such as increasing the production of alkylated oils. Alkylated oils have become an important alternative to MTBE due to their high octane rating and the absence of aromatics, sulfur, or olefins. UOP has developed an indirect alkylation process called InALK, which does not use isobutane; instead, isobutylene itself or it together with other C3–C5 olefins undergoes alkylation in the presence of a catalyst. The alkylated oil produced has an octane number of 98–99, which is higher than that of conventional alkylated oils. IFP has introduced the “virtual alkylation” process. This process uses C4 components rich in isobutylene as raw material, dimerizing isobutylene to produce gasoline containing branched alkenes, which is then hydrogenated to yield gasoline rich in isooctane. In addition, ExxonMobil Research & Engineering has developed an olefin-to-gasoline process that allows light olefins such as propylene and butylene to be polymerized into high-octane gasoline components, suitable for refineries that have access to propylene but lack alkylation units. ExxonMobil has also developed a process for converting propylene and water into diisopropyl ether (DIPE). DIPE possesses excellent properties for gasoline blending, particularly outstanding motor octane number characteristics, and its performance is no less superior than that of MTBE. As a competitive ether oxide, its role is growing day by day. For surplus MTBE plants, they can be converted to produce isooctane or ETBE in the future. When switching to the production of isooctane, the existing plant can use the same raw material as for MTBE synthesis, namely isobutylene, which is dimerized to form isooctene; this isooctene is then hydrogenated to produce isooctane. Isooctane is an excellent component for gasoline blending, with a Motor Octane Number of 100. This isobutylene conversion technology can be used to modify MTBE plants. Companies that possess this technology include Axens North America, CDTech, Liodell, KBR, and UOP, among others. In short, there are various successful methods for replacing MTBE; the adoption of alcohol-based gasoline is an inevitable trend, and the development of bioethanol is the most direct and practical solution for replacing MTBE. Currently, developed countries are accelerating the development of cellulose ethanol technology, with an increasing number of medium-scale and pilot cellulose ethanol plants being built and put into operation. It is expected that in the near future, cellulose ethanol will achieve technological and cost breakthroughs, becoming a major substitute for MTBE and an important component of gasoline. Applications in Asia will also increase, but MTBE still has great potential for development in Asia, especially in China and India. China’s current MTBE production capacity is 1.2 million tons per year, nearly doubling the 612,000 tons per year level in 2003. This is mainly due to the rapid growth in China’s gasoline demand. Many Asian countries will also implement the Kyoto Protocol, which requires member states to reduce greenhouse gas emissions in the coming years. In the short term, as action plans for ethanol and other renewable fuels have not yet been fully implemented in Asia, the use of MTBE there is likely to increase.

It seems that the research upstairs is quite in-depth; I would like to know whether the production of MTBE is an exothermic reaction If so, to what extent approximately? Thank you for your advice!

It is an exothermic reaction; the temperature rise in industrial installations is generally around 30 degrees b] 5# yanyu002

This post was last edited by chengkang on 2009-9-18 at 16:34. Methanol + isobutylene —> MTBE + 37 kJ/mol is an exothermic reaction, accompanied by many side reactions. Furthermore, this reaction is a reversible reaction. If the catalyst falls to the bottom of the tower, it will cause MTBE to be converted back into methanol and isobutylene.

In China, MTBE is not likely to be replaced in the near future, and bioethanol is still in the research stage. Given the existing technology and national conditions, it’s impossible to waste so much grain; after all, addressing basic food needs is more crucial, haha

Our company is the technical agent for PO/MTBE technologies of Huntsman Corporation in the United States; the raw material used is isobutane. Feel free to contact me if you are interested! stevenli0322@yahoo.com.cn

We are a trading company and would like to know what the export tax rebate for ETBE is. Does anyone know? There are also import tariffs on ethanol; thank you in advance

We are a trading company and would like to know what the export tax rebate for ETBE is. Does anyone know? There are also import tariffs on ethanol; thank you in advance