Eastman chemicals from coal

The Eastman Chemicals from Coal faciUty is a series of nine complex interrelated plants. These plants include air separation, slurry preparation, gasification, acid gas removal, sulfur recovery, CO /H2 separation, methanol, methyl acetate, and acetic anhydride. A block flow diagram of the process is shown in Eigure 3. The faciUty covers an area of 2.2 x 10 (55 acres) at Eastman s main plant site in Kingsport, Teimessee. The air separation plant is... 

In recent years several commercial plants have been constructed for conversion of coal to synthesis gas for chemical manufacturing. These include the Eastman Chemical s acetic anhydride plant, the Ube (Japan) ammonia plant, the SAR (Germany) oxo chemicals plant, and several coal to ammonia plants in China (e.g., Weihe, Huainan, and Lunan). The Ube plant and the SAR plant have since converted to lower-cost opportunity fuels (petroleum coke and residues). The Eastman plant is still operating exclusively on coal. Feedstock changes at the other plants illustrate the vulnerability of coal conversion processes to a changing economic climate. The fact that the Eastman process remains competitive under changing conditions is due to a set of special circumstances that favor a coal-based process. The success of the Eastman chemicals from coal complex demonstrates that synthesis gas from coal is a viable feedstock for some industrial chemicals under certain conditions. 

The Eastman Chemicals from Coal Plant has been demonstrated to provide an economically attractive process for commercial production of acetic anhydride. It is instructive to recapitulate some of the factors that contribute to this situation. 

The gasification plant is equipped with two Texaco gasifiers, each capable of producing all of the synthesis gas required for operation of the complex. Eastman chose an entrained-bed gasification process for the Chemicals from Coal project because of three attractive features. The product gas composition using locally available coal is particularly suitable for production of the desired chemicals. Also, the process has excellent environmental performance and generates no Hquids or tars. EinaHy, the process can be operated at the elevated pressure required for the downstream chemical plants. 

A chemistry based on the conversion of synthesis gas has been developed and appHed extensively in South Africa to the production of Hquid fuels and many other products. A small-scale production is used in the manufacture of photographic film materials from coal-derived synthesis gas in the Eastman Kodak plant in Kingsport, Tennessee. However, the principal production of chemicals from coal involves the by-products of coke manufacturing. 

The first U.S. manufacturer to produce a slate of industrial chemicals from coal was Eastman Chemical Company (Division of Eastman Kodak Company). Commercial facilities include a coal gasification plant for synthesis gas manufacture, raw gas cleanup... 

R. G. Smith, Chemicals from Coal Operations, Gasification Department, Eastman Chemical Company. A report presented at the 2000 Gasification Technologies Conference, San Francisco, Oct. 8-11, 2000. 

Bcrgier, A Adde acetique a partir de CO + H2" (in French), Parole et Techniques (257) 23-26 (1978). Eastman s new gamble chemicals from coal , Chem Week 134(16) 34-36 (1984). 

In 1983 Eastman Chemical Company began operating a facility to convert coal to acetic anhydride. This represented the first modem chemicals from coal facility and used coal based synthesis gas to generate acetic anhydride. The lynchpin technologies were a unique, first of its kind, reactive distillation of acetic acid and methanol to generate methyl acetateand the subsequent carbonylation of methyl acetate to generate acetic anhydride. 

Zoellei J.R. (2009) Eastman chemical company s Chemicals from Coal program The first quarter century. Catal. Today, 140,118—126. 

Production of various chemicals from coal gas produced in 11 Texaco gasifiers at chemical plants in the United States (Teimessee Eastman), West Germany, Japan, and China... 

Chemicals from Coal at Eastman Chemical Company... 

A flow sheet of Eastman s chemicals from coal plant is shown in Fig. 17.37. A simplified description of the main plants in the complex follows. 

Eastman Goal Chemicals. In 1983 Eastman Chemical Co. became the first chemical producer in the United States to return to coal as a raw material for large-scale manufacture of industrial chemicals (35). In that year, Eastman started manufacturing acetic anhydride from coal. Acetic anhydride is a key intermediate for production of coatings, ceUulosic plastics, and cellulose acetate fibers. Acetic anhydride from other sources also is used in the manufacture of pharmaceuticals, starches and sweeteners, and flavors and fragrances. 

Production of Eastman s entire acetic anhydride requirement from coal allows a reduction of 190,000 m /yr (1.2 million barrels/yr) in the amount of petroleum used for production of Eastman chemicals. Now virtually all of Eastman s acetyl products are made in part from coal-based feedstocks. Before the technology was introduced, these chemicals had been made from petroleum-based acetaldehyde. Reduced dependence on petroleum, much of which must be obtained from foreign sources, is important to maintain a strong domestic chemical industry. 

The most successful example of generating chemicals directly from coal is the Tennessee Eastman integrated process for producing acetic anhydride. The commercial plant gasifies approximately 900 tons of coal per day and performs four chemical steps to yield annually 500 million pounds of acetic anhydride, 390 million pounds of methyl acetate, and 365 million pounds of methanol. In addition, 150 million pounds per year of acetic acid may be produced from acetic anhydride. 

In 1980, the Tennessee Eastman unit of Eastman Kodak announced that it would begin construction of a facility to make acetic anhydride from coal, which was readily available at reasonable cost.17 18 This decision reflected a changing of the raw materials base of much of the chemical industry due to such factors as the rising cost of natural gas and petroleum and the large coal reserves of the United States. 

Eastman Chemical Company, together with Halcon, developed a commercial acetic anhydride process to an industrial scale [41b, 47]. This process starts with coal to make a hydrogen-rich synthesis gas, which is purified (Figure 4). A portion of the syn gas is separated to produce methanol from 2 1 H2/CO. Part of the methanol is used to scrub H2S from the coal-gasification step. The remainder of the methanol is combined with acetic acid to make methyl acetate. The methyl acetate is carbonylated to give acetic anhydride. The acetic anhydride is used to produce cellulose acetate in another process, and the resulting acetic acid is recycled to the esterification section. The acetic anhydride step of the pro-... 

Eastman Chemical uses this route in their coal to chemicals facility in Kingsport, Tennessee. By-product acetic acid from downstream cellulose esters manufacture is used to react with methanol to form the methyl acetate reactant [13]. An alternative scheme when by-product acetic acid is... 

Eastman Chemical Co. and Air Products and Chemicals, Inc. Removal of Trace Contaminants from Coal-Derived Synthesis Gas Topical Report, Contract DE-FC22-92PC90543, March 2003. 

The period from 1970 to 1985 saw radical changes in the production of acetic acid and acetic anhydride. By 1985, both products would be generated not from ethylene, but from synthesis gas which in turn could be generated fi om abundant resources such as coal, natural gas, and in the future, biomass. At the end of this period, acetaldehyde became a very small contributor to the total acetyl product stream since it was no longer required to make acetic acid or acetic anhydride and ethylene would only be required to produce vinyl acetate and to meet a much diminished acetaldehyde market. These advances were the result of two significant process breakthroughs - the Monsanto Acetic Acid Process and the Eastman Chemical Company Acetic Anhydride Process which will be discussed below. 

The Eastman process was the first modem coal-to-chemicals facility. Coal is converted to synthesis gas (CO + H ) by reaction with water in a Lurgi reactor. The synthesis gas is then purified and converted to methanol in a heterogeneous process. Reaction of methanol with acetic acid (which is recycled from applications of acetic anhydride) produces methyl acetate, which is the starting material for the Eastman carbonylation process. 

The Texaco gasifier and a similar unit developed by The Dow Chemical Company are pressurized entrained gasifiers. At the top pulverized coal is mixed with reaction gas and is blown down into the gasifier. The reaction products leave from the side, and ash is blown down to a water pool where it is quenched. These units have operated at an Eastman Kodak facUity in Kingsport, Tennessee and at the Coolwater power station in California for an integrated combined cycle power plant. 

Methanol is an ideal starting material for the synthesis of many chemicals. It is the most important feedstock for the large-scale commercial production of acetic acid and formaldehyde. Additionally, a variety of other chemicals such as methyl esters, methyl halides and methyl ethers can be produced from it. Tenessee-Eastman s recent pioneering commercialization of a coal-based process for acetic anhydride production illustrates the growing importance of methanol as chemical feedstock. 

Higher crude oil prices had revived studies in the use of coal as a chemical feedstock. But while the Fischer-Tropsch synthesis was still used in South Africa by Sasol, the only other industrial gasification unit was the one Eastman Kodak brought on stream in Kingsport, Tennessee, in 1983, to produce coalbased acetic anhydride. The coal came from the Appalachian mountains and was cheap enough relative to oil prices at the time to warrant such an installation, and the plant is now to be expanded. 

The technological innovations of the Eastman process have important implications for the use of coal, both as an energy source and as chemical feedstock. This is because it was the first commercial demonstration of modern coal gasification, which solved many of the perennial operational problems of gasification technology. It was also the first commercial application of reactive distillation, where methyl acetate is manufactured from methanol and acetic acid in the distillation column. 

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