Retorting processes

Sucrose Esters. These newer emulsifiers, approved for direct addition in the United States in 1983 (35), ate formed when sucrose is combined with various fatty acids and the resulting emulsion is dehydrated. These additives are odorless and tasteless, and can withstand the retort process. They are used in products when standards of identity do not preclude their use, such as baked goods, baking mixes, dairy product analogues, fto2en dairy desserts and mixes, and whipped milk products (39). High price has limited use in the United States, but these compounds ate used extensively in Japan as emulsifiers in baked goods (40). 

Types of internal enamel for food containers include oleoresins, vinyl, acryflc, phenoHc, and epoxy—phenoHc. Historically can lacquers were based on oleoresinous products. PhenoHc resins have limited flexibiHty and high bake requirements, but are used on three-piece cans where flexibiHty is not required. Vinyl coatings are based on copolymers of vinyl chloride and vinyl acetate dissolved in ketonic solvents. These can be blended with alkyd, epoxy, and phenoHc resins to enhance performance. FlexibiHty allows them to be used for caps and closures as weU as drawn cans. Their principal disadvantage is high sensitivity to heat and retorting processes this restricts their appHcation to cans which are hot filled, and to beer and beverage products. 

A vacuum-retort process (Pidgeon process) was used during World War II for the production of magnesium and calcium. SiHcon, in the form of ferrosihcon, was used as the reducing agent instead of carbon to avoid the problem of cooling magnesium vapor in the presence of carbon dioxide ... 

Temperature and Product Yields. Most oil shale retorting processes are carried out at ca 480°C to maximize liquid product yield. The effect of increasing retort temperature on product type from 480 to 870°C has been studied using an entrained bed retort (17). The oil yield decreased and the retort gas increased with increased retorting temperature the oil became more aromatic as temperature increased, and maximum yields of olefinic gases occurred at about 760°C. Effects of retorting temperatures on a distillate fraction (to 300°C) are given in Table 6. 

Carbonate Decomposition. The carbonate content of Green River oil shale is high (see Table 4). In addition, the northern portion of the Piceance Creek basin contains significant quantities of the carbonate minerals nahcoUte and dawsonite. The decomposition of these minerals is endothermic and occurs at ca 600—750°C for dolomite, 600—900°C for calcite, 350—400°C for dawsonite, and 100—120°C for nahcohte. Kinetics of these reactions have been studied (19). Carbon dioxide, a product of decomposition, dilutes the off-gases produced from retorting processes at the above decomposition temperatures. 

PETROSIX. The PETROSIX technology is operated in the IH mode using hot recycle gas as the heat-transport medium. The PETROSIX retort has only one level of heat input, uses countercurrent flows, and uses a circular grate to control the flow of soflds (Eig. 3). The PETROSIX has been operated by Petrobras (Brazil) since the 1950s and is one of the few retorting processes producing shale oil in 1995. 

Zinc occurs most abundantly in tire mineral. Sphalerite, ZnS, which is roasted to produce the oxide before the metal production stage. The products of the roast are then reduced by carbon to yield zinc oxide and CO(g). In the older process, tire Belgian retort process, the metal oxide and carbon are mixed together in a reactor which allows the indirect heating of the charge to produce the gaseous products followed by tire condensation of zinc at a lower temperature in a zone of the reactor which is outside the heating chamber. The carbon monoxide is allowed to escape from the vessel and is immediately burnt in... 

This continuous process is to be compared with a batch process, such as the Belgian retort process. In this, zinc oxide, free of lead or iron is reduced with carbon to produce zinc vapour, which is condensed in the cold section of the retort. The oxygen potential in this system is very much lower dran in the blast furnace, approximately at the C/CO equilibrium value. A vacuum-operated variant of dris level of reduction is caiTied out to produce zinc vapour which is subsequently converted to zinc oxide before condensation of the metal could take place. 

Muffe,/. muff (Tei h.) sleeve, etc, (see Muff). Muffel. /. muffle, -farbe, /, muffle color, -ofen, m, muffle furnace, -rostofen, m, muffle roaster, -verfahren, n. (Zinc) distillation process, retort process. 

PLATE 5 Stages in the retorting of an oil shale particle in a hot inert gas are shown. [1, 2, 3] The retorting zone moves inward as products diffuse out of the particle. A coke layer on the particle is formed as a final step of the retorting process. [4, 5, 6] Retorting goes to completion in the center of the particle, and a fully coked particle remains. Courtesy, Amoco Corporation. 

Coal gas is produced when coal is carbonized when coal is heated in the absence of air in either coke ovens in gas-producing retorts. In the gas-producing retort process, coal is fed... 

Horizontal mills, 16 65 Horizontal reactor, 22 154, 155 Horizontal retort process, for zinc, 26 577 Horizontal rotary tilting-pan filters,... 

Sklarew DS, Hayes DJ. 1984. Trace nitrogen-containing species in the offgas from 2 oil shale retorting processes. Environ Sci Technol 18 600-603. 

The direct sterilisation of particulafe solid foods in a gas-solid fluidized bed was proposed as long ago as 1968 by Lawrence et al. (1968) who sterilised wheat flour in steam-air mixtures at the pilot scale. However, Jowitt (1977) described an atmospheric pressure process for fhe sferilisation of canned foods in which the cans are immersed in a fluidized bed of inert particles. This has a number of advantages compared to the conventional retorting process using pressurised steam or hot water ... 

No information was available on the costs of using the HRS retorting process to treat hazardous or mixed wastes. Cost estimates for the full-scale application of the HRS process for oil shale retorting may be found in D120672. 

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