Chemicals feedstock production from

The correlation of coal characteristics with liquefaction behaviour has received considerable attention (see, for example refs l-7> particularly since the renewed interest during the 1970s in the production of liquid fuels and chemical feedstocks directly from coal. As early as 1940, Storch and coworkers(8,9) demonstrated that coals containing up to 87% dmmf C give high yiel of soluble products (albeit under severe conditions) and materials which today would be classified as vitrinite and inertinite liquefy readily. More recently, the work... 

Catalytic Oligomeri tion. Shell Chemical provides C —C linear internal olefin feedstock for detergent oxo alcohol production from its SHOP... 

Coal is used ia industry both as a fuel and ia much lower volume as a source of chemicals. In this respect it is like petroleum and natural gas whose consumption also is heavily dominated by fuel use. Coal was once the principal feedstock for chemical production, but ia the 1950s it became more economical to obtain most industrial chemicals from petroleum and gas. Nevertheless, certain chemicals continue to be obtained from coal by traditional routes, and an interest in coal-based chemicals has been maintained in academic and industrial research laboratories. Much of the recent activity in coal conversion has been focused on production of synthetic fuels, but significant progress also has been made on use of coal as a chemical feedstock (see Coal CONVERSION processes). 

Approximately 50—55% of the product from a coal-tar refinery is pitch and another 30% is creosote. The remaining 15—20% is the chemical oil, about half of which is naphthalene. Creosote is used as a feedstock for production of carbon black and as a wood preservative. Because of modifications to modem coking processes, tar acids such as phenol and cresyUc acids are contained in coal tar in lower quantity than in the past. To achieve economies of scale, these tar acids are removed from cmde coal tar with a caustic wash and sent to a central processing plant where materials from a number of refiners are combined for recovery. 

In 1991, the relatively old and small synthetic fuel production faciHties at Sasol One began a transformation to a higher value chemical production facihty (38). This move came as a result of declining economics for synthetic fuel production from synthesis gas at this location. The new faciHties installed in this conversion will expand production of high value Arge waxes and paraffins to 123,000 t/yr in 1993. Also, a new faciHty for production of 240,00 t/yr of ammonia will be added. The complex will continue to produce ethylene and process feedstock from other Sasol plants to produce alcohols and higher phenols. 

Relatively small amounts of methane, ethane, and propane also are produced as by-products from petroleum processes, but these usually are consumed as process or chemical feedstock fuel within the refineries. Some propane is recovered and marketed as LPG. 

Recoveries of 90—95% ethane have been achieved usiag the expander processes. The Hquid product from the demethanizer may contain 50 Hquid vol % ethane and usually is deHvered by a pipeline to a central fractionation faciHty for separation iato LPG products, chemical feedstocks, and gasoline-blending stocks. 

The advent of a large international trade in methanol as a chemical feedstock has prompted additional purchase specifications, depending on the end user. Chlorides, which would be potential contaminants from seawater during ocean transport, are common downstream catalyst poisons likely to be excluded. Limitations on iron and sulfur can similarly be expected. Some users are sensitive to specific by-products for a variety of reasons. Eor example, alkaline compounds neutralize MTBE catalysts, and ethanol causes objectionable propionic acid formation in the carbonylation of methanol to acetic acid. Very high purity methanol is available from reagent vendors for small-scale electronic and pharmaceutical appHcations. 

Petroleum refining, also called petroleum processing, is the recovery and/or generation of usable or salable fractions and products from cmde oil, either by distillation or by chemical reaction of the cmde oil constituents under the effects of heat and pressure. Synthetic cmde oil, produced from tar sand (oil sand) bitumen, and heavier oils are also used as feedstocks in some refineries. Heavy oil conversion (1), as practiced in many refineries, does not fall into the category of synthetic fuels (syncmde) production. In terms of Hquid fuels from coal and other carbonaceous feedstocks, such as oil shale (qv), the concept of a synthetic fuels industry has diminished over the past several years as being uneconomical in light of current petroleum prices. 

Until the end of World War II, coal tar was the main source of these aromatic chemicals. However, the enormously increased demands by the rapidly expanding plastics and synthetic-fiber industries have greatly outstripped the potential supply from coal carbonization. This situation was exacerbated by the cessation of the manufacture in Europe of town gas from coal in the eady 1970s, a process carried out preponderantly in the continuous vertical retorts (CVRs), which has led to production from petroleum. Over 90% of the world production of aromatic chemicals in the 1990s is derived from the petrochemical industry, whereas coal tar is chiefly a source of anticorrosion coatings, wood preservatives, feedstocks for carbon-black manufacture, and binders for road surfacings and electrodes. 

Since the bulk of butadiene is recovered from steam crackers, its economics is very sensitive to the selection of feedstocks, operating conditions, and demand patterns. Butadiene supply and, ultimately, its price are strongly influenced by the demand for ethylene, the primary product from steam cracking. Currently there is a worldwide surplus of butadiene. Announcements of a number of new ethylene plants will likely result in additional butadiene production, more than enough to meet worldwide demand for polymers and other chemicals. When butadiene is in excess supply, ethylene manufacturers can recycle the butadiene as a feedstock for ethylene manufacture. 

In addition to supplying transportation fuels and chemicals, products from coal liquefaction and extraction have been used m the past as pitches for binders and feedstocks for cokes [12]. Indeed, the majority of organic chemicals and carbonaceous materials prior to World War II were based on coal technologies. Unfortunately, this technology was supplanted when inexpensive petroleum became available dunng the 1940s. Nevertheless, despite a steady decline of coal use for non-combustion purposes over the past several decades, coal tars still remain an important commodity in North America. 

Higher molecular weight hydrocarbons present in natural gases are important fuels as well as chemical feedstocks and are normally recovered as natural gas liquids. For example, ethane may be separated for use as a feedstock for steam cracking for the production of ethylene. Propane and butane are recovered from natural gas and sold as liquefied petroleum gas (LPG). Before natural gas is used it must be processed or treated to remove the impurities and to recover the heavier hydrocarbons (heavier than methane). The 1998 U.S. gas consumption was approximately 22.5 trillion ft. ... 

Liquefied petroleum gas (LPG), which is a propane-butane mixture. It is mainly used as a fuel or a chemical feedstock. Liquefied petroleum gas is evolving into an important feedstock for olefin production. It has been predicted that the world (LPG) market for chemicals will grow from 23.1 million tons consumed in 1988 to 36.0 million tons by the year 2000. ... 

Material recycling is the objective for every material, but at some point reuse or collection, separation and further recycling will no longer yield a useful product. The so-called plastic waste still contains a high calorific value which can be recovered to produce heat or electricity. Even better it may be possible to recover the chemical feedstock originally manufactured from oil. These two possibilities are reviewed. 

Carbamate, RNHCOOR, produced from carbonylation pathways can be selectively converted to isocyanate (1.4). Carbonylation pathways offer a number of advantages (i) the environmentally benign nature of the reactants, (ii) the high selectivity of the reaction processes, (iii) the stability and low toxicity of carbamate products and (iv) the wide range of applications of carbamate as chemical feedstock. 

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