Ton, metric

Catfish are not a major contributor to aquaculture production globally, but the channel catfish industry dominates United States aquaculture. United States catfish production, primarily channel catfish, was 209,090 metric tons in 1992 (4). 

Among the invertebrates, most of the world s production is associated with mussels, oysters, shrimp, scallops, and clams. Crawfish culture is of considerable importance in the United States, but amounted to only 24,211 metric tons in 1992 (4) insignificant compared to some other invertebrate species. 

It was not until the twentieth century that furfural became important commercially. The Quaker Oats Company, in the process of looking for new and better uses for oat hulls found that acid hydrolysis resulted in the formation of furfural, and was able to develop an economical process for isolation and purification. In 1922 Quaker announced the availability of several tons per month. The first large-scale appHcation was as a solvent for the purification of wood rosin. Since then, a number of furfural plants have been built world-wide for the production of furfural and downstream products. Some plants produce as Httie as a few metric tons per year, the larger ones manufacture in excess of 20,000 metric tons. 

Worldwide furfuryl alcohol capacity in 1993 was estimated to be 110,000 metric tons (38). As with furfural, new capacity in developing countries is replacing older capacity in developed countries. China and South Africa have become significant producers of furfuryl alcohol. New plants have been built in Asia and Indonesia as well. Consumption of furfuryl alcohol is spread over the globe the largest use is in the foundry industry which is increasingly moving away from heavily industrialized countries. 

Production and Shipment. Estimated adiponitrile production capacities in the U.S. in 1992 were about 625 thousand metric tons and worldwide capacity was in excess of lO metric tons. The DOT/IMO classification for adiponitrile is class 6.1 hazard, UN No. 2205. It requires a POISON label on all containers and is in packing group III. Approved materials of constmction for shipping, storage, and associated transportation equipment are carbon steel and type 316 stainless steel. Either centrifugal or positive displacement pumps may be used. Carbon dioxide or chemical-foam fire extinguishers should be used. There are no specifications for commercial adiponitrile. The typical composition is 99.5 wt % adiponitrile. Impurities that may be present depend on the method of manufacture, and thus, vary depending on the source. 

Every continent, except Antarctica, grows com 40% of the present world crop is produced in the United States. In the 1987—1988 crop year, 12 states (Iowa, HI., Nebr., Minn., Ind., Ohio, Wis., Mo., S. Dak., Mich., Kans., and Tex. in order of production) produced 157.5 million metric tons (6.2 biUion bushels) that was 88% of the United States and 36% of the world s crop (66). Yield is influenced by many factors, including climate, pest control, planting density, and fertilization. Yield in the United States has increased from about 1.5 metric tons /hectare in the 1930s to about 7.5 metric tons /hectare. In 1985, a test plot produced 23.2 metric tons /hectare and yields approaching 40 metric tons /hectare are considered possible com is the most productive of the principal food crops. 

The United States wet millers buy ca 15% of the com used in the U.S. (worldwide, wet millers consume about 10% of the com used). There are two dozen com wet mills in the United States ranging in capacity from 600—10,000 metric tons/day. SheHed com is shipped to wet millers by tmck, rail, or barge. 

Naturally occurring abrasives are still an important item of commerce, although synthetic abrasives now fill many of thek former uses. In 1987 about 156 million metric tons of natural abrasives were produced in the United States. Production was up from 1986 because of increased nonabrasive uses and increased use of garnet in sandblasting (4). 

Steel Shot and Grit. Steel shot and grit are also widely used ia grit blasting and abrasive finishing. In 1989, 220, 196 metric tons of metallic abrasives were produced in the United States with a combined value of 89.55 million (20). 

Economic Aspects. Eigures on U.S. production, imports, and projected demand of chloroacetic acid are Hsted in Table 2 (24). The majority of imported chloroacetic acid is produced in Germany. Western European capacity for chloroacetic acid is in excess of 225,000 metric tons per year. In 1990 the price was 1.25 to 1.36/kg (24,25). 

Until World War 1 acetone was manufactured commercially by the dry distillation of calcium acetate from lime and pyroligneous acid (wood distillate) (9). During the war processes for acetic acid from acetylene and by fermentation supplanted the pyroligneous acid (10). In turn these methods were displaced by the process developed for the bacterial fermentation of carbohydrates (cornstarch and molasses) to acetone and alcohols (11). At one time Pubhcker Industries, Commercial Solvents, and National Distillers had combined biofermentation capacity of 22,700 metric tons of acetone per year. Biofermentation became noncompetitive around 1960 because of the economics of scale of the isopropyl alcohol dehydrogenation and cumene hydroperoxide processes. 

Other Uses. More than 70 thousand metric tons of acetone is used in smaU volume appHcations some of which are to make functional compounds such as antioxidants, herbicides, higher ketones, condensates with formaldehyde or diphenylamine, and vitamin intermediates. 

Ma.nufa.cture. Most butanediol is manufactured in Reppe plants via hydrogenation of butynediol. Recendy an alternative route involving acetoxyiation of butadiene has come on stream and, more recendy, a route based upon hydroformylation of allyl alcohol. Woddwide butanediol capacity has climbed steadily for many years. In 1990 it was estimated to be 428,000 metric tons (141), as compared to a Htde more than 70,000 metric tons in 1975... 

Historically, the development of the acrylates proceeded slowly they first received serious attention from Otto Rohm. AcryUc acid (propenoic acid) was first prepared by the air oxidation of acrolein in 1843 (1,2). Methyl and ethyl acrylate were prepared in 1873, but were not observed to polymerize at that time (3). In 1880 poly(methyl acrylate) was reported by G. W. A. Kahlbaum, who noted that on dry distillation up to 320°C the polymer did not depolymerize (4). Rohm observed the remarkable properties of acryUc polymers while preparing for his doctoral dissertation in 1901 however, a quarter of a century elapsed before he was able to translate his observations into commercial reaUty. He obtained a U.S. patent on the sulfur vulcanization of acrylates in 1912 (5). Based on the continuing work in Rohm s laboratory, the first limited production of acrylates began in 1927 by the Rohm and Haas Company in Darmstadt, Germany (6). Use of this class of compounds has grown from that time to a total U.S. consumption in 1989 of approximately 400,000 metric tons. Total worldwide consumption is probably twice that. 

Production of the 2-cyanoacryhc ester adhesives on a worldwide basis is estimated to be approximately 2400 metric tons. This amounts to only 0.02% of the total volume of adhesives produced but about 3% of the doUar volume. 

Coa.1 Reserves. As indicated in Table 2, coal is more abundant than oil and gas worldwide. Moreover, the U.S. has more coal than other nations U.S. reserves amount to about 270 biUion metric tons, equivalent to about 11 x 10 MJ (1 x 10 ° BTU = 6600 quads), a large number compared to the total transportation energy use of about 3.5 x lO " MJ (21 quads) per year (11). Methanol produced from U.S. coal would obviously provide better energy security benefits than methanol produced from imported natural gas. At present however, the costs of producing methanol from coal are far higher than the costs of producing methanol from natural gas. 

Table 2. World Estimated Recoverable Reserves of Coal in Billions of Metric Tons...

Higher aliphatic alcohols (C —C g) are produced ia a number of important industrial processes using petroleum-based raw materials. These processes are summarized in Table 1, as are the principal synthetic products and most important feedstocks (qv). Worldwide capacity for all higher alcohols was approximately 5.3 million metric tons per annum in early 1990, 90% of which was petroleum-derived. Table 2 Hsts the major higher aliphatic alcohol producers in the world in early 1990. 

The 0X0 or hydroformylation reaction was discovered in Germany in 1938 (10) and was first used on a commercial scale by the Enjay Chemical Company (now Exxon) in 1948. By 1990 the total world alcohol capacity based on this general technology was over four million metric tons per year (see Oxo... 

Chlorine cannot be stored economically or moved long distances. International movements of bulk chlorine are more or less limited to movements between Canada and the United States. In 1987, chlorine moved in the form of derivatives was 3.3 million metric tons or approximately 10% of total consumption (3). Exports of ethylene dichloride, vinyl chloride monomer, poly(vinyl chloride), propylene oxide, and chlorinated solvents comprise the majority of world chlorine movement. Countries or areas with a chlorine surplus exported in the form of derivatives include Western Europe, Bra2il, USA, Saudi Arabia, and Canada. Countries with a chlorine deficit are Taiwan, Korea, Indonesia, Vene2uela, South Africa, Thailand and Japan (3). 

Sodium Bicarbonate. Many soda ash plants convert a portion of their production to sodium bicarbonate [144-55-8], NaHCO. Soda ash is typically dissolved, carbonated, and cooled to crystallize sodium bicarbonate. The mother Hquor is heated and recycled. The soHd bicarbonate is dried in flash or tray driers, screened, and separated into various particle size ranges. Bicarbonate markets include food, pharmaceuticals, catde feed, and fire extinguishers. U.S. demand was approximately 320,000 t in 1989 world demand was estimated at one million metric tons. 

Continuous Solvent—Extrusion Process. A schematic for a typical continuous process, widely used for making solvent propellant for cannons, is shown in Figure 7. This continuous process produces ca 1100 metric tons of single-base propellant per month at the U.S. Army Ammunition Plant (Radford, Virginia). Continuous processes have also been developed for double- and triple-base propellants and for stick as well as granular geometries. A principal aspect of these processes has been the extensive use of single- and double-screw extmders instead of the presses used in the batch process. 

Olefin Feedstock Selection. The selection of feedstock and severity of the cracking process are economic choices, given that the specific plant has flexibiUty to accommodate alternative feedstocks. The feedstock prices are driven primarily by energy markets and secondarily by supply and demand conditions ia the olefins feedstock markets. The prices of iadividual feedstocks vary widely from time to time as shown ia Figure 2, which presents quarterly prices of the various feedstocks ia the United States from 1978 through 1991 ia dollars per metric ton (1000 kg) (4). 

The only other petrochemical feedstock of significant commercial use is methane (natural gas) which is used primarily to produce ammonia and methanol. Consumption factors are about 28 GJ and 31 GJ per metric ton, respectively (58,300 and 64,700 BTU/lb) (8). Approximately... 

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