PERP Program – New Report AlertOctober 2003 Nexant’s ChemSystems Process Evaluation/Research Planning program has published a new report, Acetic Acid (02/03-1). Acetic acid is a raw material for several key petrochemical intermediates and products including vinyl acetate monomer (VAM), acetate esters, cellulose acetate, acetic anhydride, monochloroacetic acid (MCA), etc., as well as a key solvent in the production of purified terephthalic acid (PTA). No other large volume industrial organic chemical can claim the varied feedstocks and production approaches that acetic acid can. As shown in the figure below, commercially employed feedstocks include: (1) natural gas based derivatives methanol and carbon monoxide, (2) ethylene and ethylene derivatives, (3) alkanes such as ethane, butane, and naphtha, (4) syngas derived from coal, and (5) renewable natural sources. All of these carbon sources are still in commercial use for acetic acid production; however the proportion that each of these feedstocks contributes to total acetic acid production has changed over time and will continue to do so, as seen in the next figure. Feedstock Choices and Process Routes for Acetic Acid Production Liquid Phase Oxidation Naphtha or NGLs Ethylene Direct Vapor Phase Oxidation * Liquid Phase Oxidation Acetaldehyde Direct Vapor Phase Natural Gas Ethane Oxidation * Acetic Acid Methanol Fuel Oil Syngas Coal Carbon Monoxide Methanol Carbonylation * Fermentation Carbohydrates Q303_4108.ppt * Comparative process economics analyzed in this study 000 3.000 1. was followed by oxidation and then carbonylation processes. and is now headed back to oxidation and fermentation technologies. the Wacker 2-step ethylene oxidation process via acetaldehyde became a commercial process. Celanese announced last year its intention to develop a novel high tech biocatalytic process for acetic acid manufacturing.xls\F2 Before 1960.Acetic Acid Feedstock Change in the U. 4. taking advantage of the inexpensive ethane feedstock readily available in the Middle East. In the 1960s. natural biosynthesis using sugars and alcohols and non-selective alkane activation using butane and naphtha were the major technologies employed for acetic acid production. Thousand Metric Tons 4.000 2.500 Capacity. During the last few years.S.E. supplanting the cobalt iodode catalyzed high pressure process pioneered by BASF in 1960. Showa Denko commercialized an improved ethylene oxidation process by using a one-step oxidation process instead of the old 2step oxidation as used in the Wacker process. In the late 1990s.500 2. Finally. In the 1970s Monsanto developed the rhodium/iodide catalyst system for methanol carbonylation. This technology features acetic acid selectivity greater than 99 percent based on methanol.500 3. .500 1. In 1986. SABIC revived the alkane activation technology by catalytically oxidizing ethane to selectively and directly produce acetic acid. and W. which has further developed the process.000 500 0 1973 Methanol 1993 Butane/Naphtha Acetaldehyde 2002 Q303_4108-Charts. It is interesting to note that the development of acetic acid technology began with fermentation. while methanol carbonylation technology began to emerge as a serious contender and has become today’s dominant acetic acid technology. ownership of the Monsanto technology was acquired by BP. An overview of Monsanto/BP’s catalyst system in comparison with that of Celanese AO Plus. Catalyst Systems For Methanol Carbonylation Company/Technology Monsanto/BP Celanese AO Plus BP Cativa Chiyoda Acetica Central Catalyst Atom Rhodium Rhodium Iridium Rhodium Cocatalyst (Promoter) CH3I/HI LiI/CH3I CH3I/Re or Ru CH3I/Immobilized Complex on solid support Methanol carbonylation technology is presently the dominant acetic acid production technology accounting for over 65 percent of global capacity. However. and Chiyoda Corporation (Acetica Process). Showa Denko has developed a one step. vapor phase process for the production of acetic acid by direct oxidation of ethylene. BP Cativa. BP (Cativa Process). the Showa Denko ethylene based process is claimed to be economical for relatively small 50. Owing to relatively reduced capital outlays needed (no carbon monoxide production). and Chiyoda Acetica processes is given in the following table.-3- CH3OH + CO Q303_4108-2. commercialized in late 1997.000 to 100. Acetic acid is produced with high selectivity from a mixture of ethylene and oxygen in the vapor phase at 160 to 210°C over supported palladium based catalyst. because of the high price of rhodium and an expensive and elaborate rhodium recovery section. The “world-scale” of acetic acid plant size using methanol carbonylation technology has also grown significantly from less than 50 thousand metric tons per year in the 1960s to greater than 1 billion metric tons per year currently.000 ton per year acetic acid plants. Improvements to the original Monsanto/BP technology have been introduced by Celanese (AO Plus Process). and this share is growing because it generally affords the lowest cost acetic acid.cdx CH3COOH The rhodium catalyzed methanol carbonylation process is highly selective and operates under mild reaction pressure (around 500 psia). . The major side reactions are the combustion of ethylene and the production of acetaldehyde. new developments and other catalysts for methanol carbonylation are continually being investigated. to form acetic acid according to the following stoichiometry: C2H6 + 1. Nb.cdx CH3COOH + H2O Undesired by-products of CO. respectively. per-pass selectivities to acetic acid. Gulf Coast and Middle East locations by the following processes: Methanol carbonylation .e. acetaldehyde (recycled).BP Cativa . and ethylene (largely lost on recycle) can also be formed. at temperatures ranging from 150°C to 450°C and at pressures ranging from 1 to 50 bar. ethane lean).6 percent and again at 100 percent conversion of oxygen. and 5. Showa Denko has developed an environmentally friendly. ethane rich) or air (i. 8.2 percent.S. When an ethane-oxygen system is employed. According to SABIC’s patents.5 percent. V. The report presents and compares cost of production estimates for acetic acid at U.5 O2 Q303_4108-2.-4- C2H4 + O2 Q303_4108-2. energy saving process by combining the extraction and the distillation operation in which by-product water is efficiently separated from acetic acid. CO2.e. respectively.6 percent and 100 percent of ethane and oxygen. Alternatively.Monsanto/BP . SABIC has developed a new process for producing acetic acid via catalytic gas phase oxidation of ethane..Celanese AO Plus . the selectivity to acetic acid is slightly lower at 60 percent but at a much higher per pass conversion of ethane of 49.Chiyoda Acetica Ethylene direct oxidation (Showa Denko) .9 percent. The new SABIC catalyst system is a calcined mixture of oxides of Mo. based on patent data. can be achieved.. An acetic acid production semi-works plant is set to have an initial capacity of 30. when an ethane-air system is employed. ethane is oxidized with either pure oxygen (i.000 metric tons per year and is slated to start up in the second quarter of 2004. and Pd. and carbon dioxide of 85. the selectivity to acetic acid can reach as high as 67 percent at per pass conversions of 13.cdx CH3COOH Under the reaction conditions employed. Global acetic acid capacity aggregated by producer is backed up with detailed producer capacity lists for the United States. The second largest market is as a solvent in the manufacture of purified terephthalic acid. some of the acetic acid solvent is also oxidized.nexant. White Plains. phone: 1-914-609-0381. adhesive. Global Director. acetic anhydride. including business intelligence.A. Japan.Oxygen-based with recycle . each with about a 25 percent share of global acetic acid capacity. The next tier of producers are Eastman. Acetic anhydride is used principally in cellulose acetate for cigarette filters. Western Europe. In this high temperature oxidation process. or Heidi Junker Coleman. Website: http://www. operational improvement. and collected other uses.com. ================================================ Nexant. New York 10601-4425 U. For over 38 years. and growth through M&A activities. Inc. printing inks. Central and South America. This is an important factor in the overall economics. and Daicel. The largest market for acetic acid is in the manufacture of vinyl acetate. project feasibility and implementation.nexant.com.com) is a leading management consultancy to the global energy. For further information about these reports contact Dr. e-mail address: [email protected] Ethane direct oxidation (SABIC) . and related industries. coatings. fax: 1-914-609-0399. Millennium. BP and Celanese are engaged in a battle for global leadership in the acetyls business area. and coating sectors. These reports are for the exclusive use of the purchasing company or its subsidiaries. phone: 1-914-609-0315. and rest of world.S. from Nexant. and adhesives. 44 South Broadway. (www.. 5th Floor. Plotkin. The commercial portion of the report presents global acetic acid demand by end use and by five world regions.Air-based without recycle An analysis of the total capital employed per unit of acetic acid produced favors the newer. East Asia. each with about 5 percent of global acetic acid capacity. . Acetate esters are oxygenated solvents with applications in pharmaceuticals. Nexant/ChemSystems has helped clients increase business value through assistance in all aspects of business strategy. and satellite offices worldwide. Major end uses are in the emulsion paint. e-mail: jplotkin@nexant. Jeffrey S. leading to the replacement requirement. Global and regional acetic acid supply/demand balances are forecast through 2010. PERP Program. megascale methanol carbonylation processes. The remaining acetic acid market is about evenly divided between acetate esters. chemical. portfolio planning. which is subsequently used in polyvinyl acetate and polyvinyl alcohol.com. Acetex. Nexant’s chemicals and petroleum group has its main offices in White Plains (New York) and London (UK). Inc.