Cement Plant Applications

Monolithic refractories are used in sections of cement kilns, typically at the outlet, where wear rates are very high. At these zones, dense silicon-carbide-based castables are often used. The cyclones in the preheater section of cement plants are lined with dense castables due to the complexity of their shape and the wear resistance required. The shell of the exhaust gas duct is made from both dense and insulating castable materials. In the cooler section of the plant, monolithic refractories are used to line the ceiling. 

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Oxidation of potassium compounds to the sulfate form occurs in the Recovery Scrubber process licensed by Passamaquoddy Technology, which was originally developed for cement plant applications. The process uses waste cement kiln dust, which contains limestone, alkali, and calcium sulfate, in an aqueous slurry as a flue gas scrubbing reagent The first commercial appUcation of the process began operating at the Dragon Products Company cement plant in Thomaston, Maine in December 1990 (Morrison, 1991). 

Diesels are used in many industrial applications (for example, for base-load generation in mines, cement plants and in remote regions of the world). In addition, they are often utilized to provide standby power for hospitals, telecommunications, banks, computer centers and office complexes that must have full independent power capability. The diesel can be started rapidly, making it ideal for peak lopping duties to meet maximum load demands, or for emergency use in cases of power supply interruptions. 

Hargave,R. V. Venkateswaran, D and Chatterjee, A.K., "Application of Optical Microscope as Quality Control Tool in Some Indian Cement Plants," Proceedings of the 9th International Conference on Cement Microscopy, International Cement Microscopy Association, Reno, Nevada, 1987, pp. 148-164. 

The fraction of particles collected is sometimes reported in terms of percent collection efficiency (after multiplication by 100). Values of such efliciencies in a few operating plants are indicated in Figure 7.3.9, which identifies only a few major types of installations. The use of electrostatic precipitators is widespread additional examples of where they are used are cement plants, in the steel industry, in smelting operations, in the chemical industry, the petroleum industry, in carbon black factories, foundries, etc. In such industrial applications, industrial practice suggests techniques other than electrostatic precipitation for particles in the range 0.1-1 pm since the value of is <0.99 and decreases with a decrease in Vp (Donovan, 1985 Eggerstedt et al., 1993). 

Figure 1.4 shows some examples of crushers and mills used in a laboratory. Ball mills are preferable for many applications, as they generally provide a narrower particle size distribution than, e.g. disk mills, such as the one shown in Figure 1.4f, and are thus closer to the conditions in a cement plant. Disk mills, like the one shown in Figure 1.4f, provide a rapid grinding process and are suitable especially for grinding prior to chemical analysis such as X-ray fluorescence analysis. 

Typical applications in the chemical field (Beaver, op. cit.) include detarring of manufactured gas, removal of acid mist and impurities in contact sulfuric acid plants, recovery of phosphoric acid mists, removal of dusts in gases from roasters, sintering machines, calciners, cement and lime Idlns, blast furnaces, carbon-black furnaces, regenerators on fluid-catalyst units, chemical-recoveiy furnaces in soda and sulfate pulp mills, and gypsum kettles. Figure 17-74 shows a vertical-flow steel-plate-type precipitator similar to a type used for catalyst-dust collection in certain fluid-catalyst plants. 

The furan or furane resins mainly find use because of their excellent chemical and heat resistance. In the past they have mainly been used in applications peripheral to the plastics industry such as foundry resins, for chemically resistant cements and for binders. Recent developments have facilitated their use in laminates for chemical plant. 

The principal applications for furan resins are in chemical plant. Specific uses include the lining of tanks and vats and piping and for alkali-resistant tile cements. The property of moisture resistance is used when paper honeycomb structures are treated with furan resins and subsequently retain a good compression strength even after exposure to damp conditions. 

Many of the typical features found in present-day electrostatic precipitators are based on work by W. A. Schmidt. One of his most important applications is the electrostatic precipitator that was installed at the Riverside Portland Cement Company in 1912. This plant handled a gas flow of 470 ni/s at the temperature of 400-500 °C. This was the first precipitator in which thin wire was used as discharge electrode. 

Details are given of the development of energy and material recycling processes for thermosetting polymer composites. Applications in the cement industry and in coal fired fluidised bed combustion plants are discussed. 3 refs. 

Potassium sulfate is used in fertilizers as a source of potassium and sulfur, both of which are essential elements for plant growth. Either in simple form or as a double salt with magnesium sulfate, potassium sulfate is one of the most widely consumed potassium salts in agricultural apphcations. It is preferred over potassium chloride for certain types of crops such as, tobacco, citrus, and other chloride—sensitive crops. Some other applications include making gypsum cements to make potassium alum in the analysis of Kjeldahl nitrogen and in medicine. 

Ash waste from combustion of oil shale is used in the cement industry, but other applications analogous to those found for ash from coal-fired power plants should be investigated (Hanni 1996 Manz 1999 Hall Livingstone 2002 Swanepoel Strydom 2002 Woolard et al. 2002). 

Type I (Normal). This is the general purpose Pordand cement used for all applications where special properties are not needed. Common applications include concretes for paving, building doors, roof decks, reinforced concrete buildings, pipes, tanks, bridges, and other precast concrete products. In 1989 Type I and Type II accounted for over 92% of the Pordand cement produced in U.S. plants. Exact data are not available that separate Type I and Type II Pordand cement, but it can be assumed that Type I production was much greater than Type II. 

In the past three years there have been major increases in the utilization of waste tires as a fuel. Applications have included power plants, tire manufacturing facilities, cement kilns, and pulp and paper production. These applications have demonstrated the capability to extract energy value from the tires in an environmentally acceptable manner, while at the same time alleviating tire disposal problems in their communities. 

Applications that can bum whole tires include a few cement kilns, large dedicated tires-for-fuel boilers, and some experimental applications in utility boilers. Applications that can use TDF include most cement kilns, many thermal decomposition units, boilers at pulp and paper plants, utility plants, and other industrial facilities. 

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