Carbon in industry

Al-Rashed, M.H. and Jones, A.G., Hannan, M. and Price, C., 1996. CFD Application on a simple geometry of batch precipitation of calcium carbonate. In Industrial Crystallization 96. Ed. B. Biscans, Progep, Toulouse, 16-19 September 1996, pp. 419M24. 

Fung et al. [15] have discussed a thermal combustion-ion chromatographic method for the determination of total organic carbon in industrial and potable waters. This method utilises a tube furnace and readily... 

R.D.A. Woode, Sodium Carbonate. In Industrial Inorganic Chemicals Production and Uses (R. Thompson, ed.), pp. 123-148. The Royal Society of Chemistry, Cambridge, UK, 1995. 

It is in this fashion that experimental data and operating experiences are searched to learn of other influencing factors and the trends they can impose. Thereby we gain a kit of tools with which to explore the suitability of activated carbon for a new venture. In this chapter we seek to give a panoramic view of lessons learned over a period of years devoted to the application of activated carbon in industrial operations. Contributions are from varied sources personal communications 1 published literature 2 3 and direct experience. Many items are based on long established plant-scale... 

Industrial applications often seek to accomplish more than one objective for example, the treatment of corn sugars and syrups may aim to remove color, bitter flavor, iron, hydroxymethylfurfural, and foam-formers. Inasmuch as the operating environment favorable for improving one property (e.g., color) may not be best for another (e.g., foaming), an experimental study of a new venture should include a simultaneous examination of all properties to be corrected. To do this, the filtrate obtained from each variation in experimental conditions is examined to learn the effect a particular set of operating conditions may have on each of the properties to be improved. This brings us to a discussion of useful functions of activated carbon in industrial applications. 

Brecevic, Lj. and Nielsen, A.E. (1990) Precipitation and properties of an amorphous calcium carbonate. In Industrial Crystallization 90 (11th Symposium, Garmisch-Partenkirchen), A. Mersmann (ed.), GVC-VDI, Dusseldorf, 241-246. 

Contents of Chitin and Calcium Carbonate in Industrially Important Marine Species... 

Atmospheric corrosion of steel is a function of location. In country air the products of corrosion are either oxides or carbonates. In industrial atmosphere sulfuric acid is present, and near the ocean some salt is in the air. Corrosion is more rapid in industrial areas because of the presence of the acid, and it is higher both near cities and near the ocean because of the higher electrical conductivity of the rain and the tendency to form soluble chlorides or sulfates, which cause the removal of protective scale. 

The performance of an activated carbon, in industrial use, depends not only on the capacity of an activated carbon but also on its retentivity, that is for how long can the carbon retain the adsorbed species, under operating conditions, without it being subsequently desorbed. Activated carbons are used in beds with the gas, vapor or liquid passing through the bed. From a practical point of view it is desirable to operate by minimization of the frequency of replacement of the activated carbon bed. The characterizations, which have been elaborated upon (Section 4.2) clearly indicate the desirability to maximize the porosity of maximum adsorption potential accessible to the adsorptive at those low relative concentrations of adsorptive which are found in industrial situations. Other factors include rates of adsorption which are dependent on intra- and inter-diffusion of the adsorbate and granules and bed construction. At the same time, these adsorbed materials must remain within the activated carbon for as long as possible. 

If an excess of magnesium is used, magnesium silicide, Mg2Si, is also produced.) The silicon obtained is a light brown hygroscopic powder. Crystalline or metallic silicon is obtained industrially by the reduction of silica with carbon in an electric arc furnace ... 

The major problem in such conversions is the degradation of the branched carbon side-chain on C-17 which is present in all abundant steroids and lacking in all steroid hormones. The most important starting material used in industry today is diosgenin from the Mexican dioscorea plant. It is degraded by the method of Marker to 16-dehydropregnenolone in 45% total yield. This compound is a key substance in the production of several hormones with anabolic, catabolic, and sexual effects. 

Sodium Chloroacetate Sodium chloroacetate [3926-62-3] mol wt 116.5, C2H2C102Na, is produced by reaction of chloroacetic acid with sodium hydroxide or sodium carbonate. In many appHcations chloroacetic acid or the sodium salt can be used interchangeably. As an industrial intermediate, sodium chloroacetate may be purchased or formed in situ from free acid. The sodium salt is quite stable in dry soHd form, but is hydrolyzed to glycoHc acid in aqueous solutions. The hydrolysis rate is a function of pH and temperature (29). 

Supercritical Extraction. The use of a supercritical fluid such as carbon dioxide as extractant is growing in industrial importance, particularly in the food-related industries. The advantages of supercritical fluids (qv) as extractants include favorable solubiHty and transport properties, and the abiHty to complete an extraction rapidly at moderate temperature. Whereas most of the supercritical extraction processes are soHd—Hquid extractions, some Hquid—Hquid extractions are of commercial interest also. For example, the removal of ethanol from dilute aqueous solutions using Hquid carbon dioxide... 

Acryhcs and modacryhcs are also useflil industrial fibers. Fibers low in comonomer content, such as Dolan 10 and Du Font s PAN Type A, have exceptional resistance to chemicals and very good dimensional stabihty under hot—wet conditions. These fibers are useflil in industrial filters, battery separators, asbestos fiber replacement, hospital cubical curtains, office room dividers, uniform fabrics, and carbon fiber precursors. The exceUent resistance of acryhc fibers to sunlight also makes them highly suitable for outdoor use. Typical apphcations include modacryhcs, awnings, sandbags, tents, tarpauhns, covers for boats and swimming pools, cabanas, and duck for outdoor furniture (59). 

The manufacture of the highly pure ketene required for ketenization and acetylation reactions is based on the pyrolysis of diketene, a method which has been employed in industrial manufacture. Conversion of diketene to monomeric ketene is accompHshed on an industrial scale by passing diketene vapor through a tube heated to 350—600°C. Thus, a convenient and technically feasible process for producing ketene uncontaminated by methane, other hydrocarbons, and carbon oxides, is available. Based on the feasibiHty of this process, diketene can be considered a more stable form of the unstable ketene. 

Chemical-grade limestone is a pure type of high calcium or dolomitic limestone used by the chemical-process industry or where exacting chemical requirements ate necessary. It contains a minimum of 95% total carbonate. In a few areas of the United States this minimum may be extended to 97 or 98%. 

Lithium Carbonate. Lithium carbonate [554-13-2], Li2C02, is produced in industrial processes from the reaction of sodium carbonate and Hthium sulfate or Hthium chloride solutions. The reaction is usually performed at higher temperatures because aqueous Hthium carbonate solubiHty decreases with increasing temperatures. The solubiHty (wt %) is 1.52% at 0°C, 1.31% at 20°C, 1.16% at 40°C, 1.00% at 60°C, 0.84% at 80°C, and 0.71% at 100°C. Lithium carbonate is the starting material for reactions to produce many other Hthium salts, including the hydroxide. Decomposition of the carbonate occurs above the 726°C melting point. 

The Iron Bla.stFurna.ee, The reduction of iron oxides by carbon in the iron (qv) blast furnace is the most important of all extractive processes, and the cornerstone of all industrial economies. Better understanding of the reactions taking place within the furnace has made possible a more efficient operation through better preparation of the burden, higher blast temperature, and sometimes increased pressure. Furnace capacity has doubled since the 1800s, whereas coke consumption has been reduced by about half The ratio of coke to iron produced on a per weight basis is ca 0.5 to 1. 

The rate of hydroformylation increases with increasing hydrogen and decreases with increasing carbon monoxide partial pressures (9), suggesting that rates of hydroformylation would be satisfactory at high H2 and low CO partial pressures. In industrial practice, however, high pressures of both H2 and CO ate required in order to stabilize the HCo(CO)4 catalyst at the temperatures necessary for practical rates (10). Commercial processes, for example, operate at >24 MPa (3480 psi) and >140 C. 

The choice of a specific CO2 removal system depends on the overall ammonia plant design and process integration. Important considerations include CO2 sHp required, CO2 partial pressure in the synthesis gas, presence or lack of sulfur, process energy demands, investment cost, availabiUty of solvent, and CO2 recovery requirements. Carbon dioxide is normally recovered for use in the manufacture of urea, in the carbonated beverage industry, or for enhanced oil recovery by miscible flooding. 

---