Intensive energy process

In the United States, aluminum sulfate is usually produced by the reaction of bauxite or clay (qv) with sulfuric acid (see Sulfuric acid and sulfur trioxide). Bauxite is imported and more expensive than local clay, generally kaolin, which is more often used. Clay is first roasted to remove organics and break down the crystalline stmcture in order to make it more reactive. This is an energy intensive process. The purity of the starting clay or bauxite ore, especially the iron and potassium contents, are reflected in the assay of the final product. Thus the selection of the raw material is governed by the overall economics of producing a satisfying product. 

The manufacture of sugar was early understood to be an energy-intensive process. Cuba was essentially deforested to obtain the wood that fueled the evaporation of water from the cane juice. When the forests were gone, the bagasse burner was developed to use the dry cane pulp, called bagasse, for fuel. Bagasse was no longer a waste product its minimal value is the cost of its replacement as fuel. 

Ores are mined and are then refined in an energy intensive process to produce pure metals, which in turn are combined to make alloys (see Metallurgy Mineral RECOVERY and processing). Corrosion occurs because of the tendency of these refined materials to return to a more thermodynamically stable state (1—4). The key reaction in corrosion is the oxidation or anodic dissolution of the metal to produce metal ions and electrons... 

The movement away from energy-intensive processes in the manufacturing sector was an important force m the reductions m energy intensity during these years. One of the most noticeable shifts was in... 

This displaced more complex, capital-and-energy-intensive processes based on acetylene or ethylene oxide ... 

Detailed information of the energy requirements of competing processes is rarely available in the open literature. However, particularly for bulk chemicals, development of a much more energy-efficient process may be expected to provide significant commercial benefits resulting in the abandonment of older energy-intensive processes. 

The overriding consideration in the selection of drying equipment is the nature and concentration of the feed. Drying is an energy-intensive process, and the removal of liquid by thermal drying will be more costly than by mechanical separation techniques. 

The evaporative recovery is a very energy-intensive process. Approximately 538 chu (970 Btu) are required to evaporate lib of water at standard atmospheric pressure. Additional energy is required to raise the temperature of the solution to its boiling point. 

Summarising the literature data it can be stated that most energy consumption in crop production is used on the field in the form of fertiliser and diesel. Only those energy-intensive processes such as drying or pelletising of haulm-type... 

Compared with hydrogen as a gas, liquid hydrogen has a much higher volume-related energy density and is, therefore, principally better suited for storage, for example, on-board vehicles and for transport applications (see also Chapter ll).4 However, hydrogen liquefaction is an energy-intensive process. 

It forms the character of the varied regions in which we take such a pride. All stone extraction involves quarrying, and potentially, it is environmentally destructive, depending on how the company manages and restores the site. This cost is offset to some extent because natural stone should last for many generations. If it is used in its natural form, the requirement for energy-intensive processing is minimal and local craft skills are kept alive. 

An alternative approach for the utilization of biomass resources for energy applications is the production of dean-buming liquid fuels. In this respect, current technologies to produce liquid fuels from biomass are typically multi-step and energy-intensive processes. Aqueous phase reforming of sorbitol can be tailored to produce selectively a clean stream of heavier alkanes consisting primarily of butane, pentane and hexane. The conversion of sorbitol to alkanes plus CO2 and water is an exothermic process that retains approximately 95% of the heating value and only 30% of the mass of the biomass-derived reactant [278]. 

Due to its highly endothermic nature, regeneration by CO2 is unfortunately a very energy intensive process. 

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