Raw materials and fuel

and manufacturing processes, will be considered only to the extent needed for a basic understanding of their chemistry fuller accounts are given elsewhere (D3,G23,K7,P13). 

Limestones vary in physical characteristics from compact rocks of low porosity to friable and highly porous ones, such as chalk, which may contain up to 25% of water. All consist essentially of calcium carbonate, normally in the polymorphic form of calcite. Other naturally occurring forms of CaCOj, such as shell deposits, are sometimes used. Many limestones contain significant amounts of minor components, either as substituents in the calcite or in accessory phases, some of which are deleterious if present in amounts exceeding a few per cent (e.g. MgO, SrO), a few tenths of a per cent (e.g. P2O5, CaF2, alkalis) or even less (some heavy metals). 

Suitable shales and clays typically have bulk compositions in the region of 55-60% Si02, 15-25% AI2O3 and 5-10% Fe203, with smaller amounts of MgO, alkalis, H2O and other components. Mineralogically, their main constituents are clay minerals, finely divided quartz and, sometimes, iron 

Pulverized coal is the most usual fuel, though oil, natural gas and lignite are also used. The contributions of the fuel to the clinker composition must be taken into account, especially with coal or lignite, which produce significant quantities of ash broadly similar in composition to the argillaceous component. The fuels also contribute sulphur. 

Due to the increasing cost of energy, the need to preserve the environment, and the non-existence or exhaustion of suitable natural raw materials in some areas, industrial and other waste materials are of interest as possible raw materials or supplementary fuels or both. Energy can be saved if even a part of the CaO can be provided by a material, such as blastfurnace slag, that does not require decarbonation. Supplementary fuels include such materials as used or reject tyres and pulverized household refuse, which can be introduced into the system in various ways. Some materials, such as pulverized fuel ash (pfa fly ash) can serve as raw materials that also possess some fuel content. Other wastes that have been used include calcium silicate residues from aluminium extraction, mining residues, and precipitated calcium carbonate from various industries. 

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Originally confined to the shipment of crude raw materials and fuels, the term transportation of bulk sohds now apphes also to manufactured produc ts, which often become raw materials for other industries. In recent years, increasing tonnages of highly processed, finished chemical products have moved to customers in large bulk units. A useful definition of a bulk shipment is any unit greater than 2000 kg (4000 lb) or 2 m (70 fF). The containers available range from small portable hoppers of 2-m (70-fF) capacity to railroad cars of 255-m (9000-fF) capacity. 

Labor costs experience inflation just as do capital costs as Figure B.5 demonstrates. Raw materials and fuel costs are subject to considerable erratic fluctuations as demonstrated by oil and metals prices, which have rapidly risen and fallen several times over the last five decades. For example, Figure B.6 shows the changes in refinery fuel price index since 1955. Prediction of refinery fuel prices in the future is clearly much more difficult than predicting capital costs. 

Under USEPA s BIF mle, manufacturers are required to closely monitor numerous conditions in the kiln and to observe limits on the following aspects of the process (a) the maximum feed rate of hazardous waste fuel (b) the maximum feed rate of metals from both raw materials and fuels (c) the maximum feed rate of chlorine from raw materials and fuels (d) the maximum feed rate of raw materials (e) the maximum temperature at the inlet to the air pollution control devices (f) the maximum concentration of carbon monoxide and total hydrocarbons in the flue gas (g) the maximum temperature in the combustion zone or minimum temperature at the kiln inlet and (h) any decrease of pressure at the baghouses or any decline in the strength of the electric field of electrostatic precipitators (both are types of air pollution control devices). 

The carbon conient of steels usually dues ntn exceed 1,7 >. In addition to carbon, j lmn einhon. steels contain small amounts of silicon, manganese, phosphorus, and sulfur derived from Ihe raw materials and fuel used in the steelmaking process. Within limitations, silicon and manganese are beneficial anti often are purposely added, mainly because they are dcoxidants. Except in free-cutting steels, where sulfur is purposely added, sulfur and phosphorus are deleterious and their content is kept as low as... 

In 1999, two American biochemical engineers with experience in microbial enzymology and genetics, both in the academic and the industrial world, Gerngross and Slater [62], were delighted with an executive order issued by former President Clinton. The order insisted that researchers should work toward replacing fossil resources with plant material both as raw material and fuel. Both men had a lot of experience in growing plastic in plants. This sounds like fiction, but it is not. Their dreams seemed to come true because... 

Acetylene (Figure 1.9) is an alkyne, a class of hydrocarbons characterized by carbon-carbon triple bonds consisting of six shared electrons. Highly flammable acetylene is used in large quantities as a chemical raw material and fuel for oxyacetylene torches. It forms dangerously explosive mixtures with air. 

Acetylene (Figure 13.1) is widely used as a chemical raw material and fuel for oxyacetylene torches. It was once the principal raw material for the manufacture of vinyl chloride (see reaction 13.2.4), but other synthetic routes are now used. Acetylene is a colorless gas with an odor resembling garlic. Though not notably toxic, it acts as an asphyxiant and narcotic and has been used for anesthesia. Exposure can cause headache, dizziness, and gastric disturbances. Some adverse effects from exposure to acetylene may be due to the presence of impurities in the commercial product. 

Portland cement clinkers contain small amounts of alkalis and sulphates derived from the raw materials and fuel. Both alkalis and SO3 can be present in the major clinker phases, but tend to combine preferentially with each other to form alkali or potassium calcium sulphates, and it is necessary to consider these components together. In addition, silicate and aluminate phases containing sulphate can form either as intermediates or in undesirable deposits in eement making, and a calcium aluminate sulphate is a major constituent of some expansive and other speeial cements. 

The data on thermal efficiency and heat consumption discussed above concern the energy under factory control only they do not include the energy associated with the production and delivery of raw materials and fuels which is equivalent or even higher than the inplant energy (see Lightfoot, 1979). 

The first consideration is that the distillery be centrally located in a potato-raising country second, that there are railroad facilities for the delivery of raw materials and fuel and the marketing of the finished product at a minimum expense. An abundant supply of cold soft water is of almost equal importance. It is desirable-that the plant be near a creek or stream from which the water may be obtained and into which it may be drained after serving its purpose in the distillery. The character of the water should also be considered, and, if possible, it should be such that it will not deposit a scale.on the boiler and condenser tubes this difficulty can be overcome, however, by treating- the water witii one of the various compounds on the market for relieving such conditions. 

J. Yamamotu, J. Tsuji, Proceedings of the Catalysis Symposium on the Shiji of Raw Materials and Fuels, The Japan Petroleum Institute, Kogakuin University, Tokyo, 2nd December, 2005, pp. 7-12. 

Uchikawa, H., and Hanehara, S., "Recycling of Waste as an Alternative Raw Material and Fuel in Cement Manufacturing," Waste Materials Used in Concrete Manufacturing, edited by S. Chandra, Noyes Publications, Westwood, New Jersey, 1997, pp. 430-554. 

Raw materials and fuels Meteoric iron X Hard X Iron ore and charcoal X coal, / coke ... 

This track record of environmental leadership by the US carpet industry has set the stage for the next phase of product stewardship - end-of-life recovery. Since most carpet components are derived from crude oil, this is the next logical area of focus. With over 2 million tonnes of old carpet going to the landfill each year, and that amount growing by approximately 2 to 3% per year, there is tremendous raw material and fuel value potential available. Details of the US carpet industry environmental accomplishments over the last decade can be found in the annual Sustainability Report issued by The Carpet and Rug Institute aud may be downloaded athttp //www.carpet-rug.com/pdf word docs/03 CRI-Sustainability-Report.pdf... 

The most abundant biomass feedstocks are carbohydrates. It follows that one of the most promising pathways to obtain useful raw materials and fuels from biomass is their synthesis directly from carbohydrates. The monosaccharides such as glucose and fructose, as well as xylose, a five-carbon sugar that is the monomer of hemicellulose, which makes up almost one-third of typical plant... 

Starting point for the analysis of the different stages of the biodiesel life cycle is again the transesterification process with its inputs, process energy and process chemicals. The other two stages of the life cycle are classified as transport, considering both collection of the raw material and fuel delivery, and the combustion of biodiesel (see Table III). 

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