Water production upgrading

In this chapter, we aim to provide an overview of the status of hydrothermal processing technologies and recent research. The chapter includes a description of associated process chemistry including a description of how the properties of water change when heated under pressure and the reaction steps in each of the hydrothermal routes. The impact and influence of different feedstocks on process operation and product distribution and composition is reviewed. Recent advances in reactor design, product upgrading, commercialization and techno-economic and Ufecycle analysis are presented before conclusions are drawn on the status of the technology. 

Thermochemical Liquefaction. Most of the research done since 1970 on the direct thermochemical Hquefaction of biomass has been concentrated on the use of various pyrolytic techniques for the production of Hquid fuels and fuel components (96,112,125,166,167). Some of the techniques investigated are entrained-flow pyrolysis, vacuum pyrolysis, rapid and flash pyrolysis, ultrafast pyrolysis in vortex reactors, fluid-bed pyrolysis, low temperature pyrolysis at long reaction times, and updraft fixed-bed pyrolysis. Other research has been done to develop low cost, upgrading methods to convert the complex mixtures formed on pyrolysis of biomass to high quaHty transportation fuels, and to study Hquefaction at high pressures via solvolysis, steam—water treatment, catalytic hydrotreatment, and noncatalytic and catalytic treatment in aqueous systems. 

There is some beneficiation of talc by froth flotation (qv), practiced especially on ultramafic-type deposits. In this process (Fig. 2), talc is milled to its hberation size (—100 mesh (ca 0.15 mm)) using ball mills or ring-type roUer mills and then slurried at 10—30% in water. Flotation is done in conventional multistage float cells using methyl amyl alcohol as a frother. Typically two to four stages are required to upgrade the ore from 50—70% talc to 90—98%. The product is filtered and then flash-dried and milled to a final product. 

The HFBR at Brookhaven National Laboratory is a heavy water moderated and cooled reactor designed to provide an intense beam of neutrons to the experimental area. In addition using thimbles i oiitaincd within the vessel, it provides isotopic production, neutron activation analysis, ami muiemi irradiations. It began operation in 1965 at a power of 40 MW to be upgraded to 60 MW m 19S2. 

Large amounts of sodium sulfate are produced as a by-product of many diverse industries. Some of this material is recycled internally, some is upgraded and sold as a product. Most is disposed as a waste in landfills, or discharged to deep-wells, or bodies of water. [129,269]... 

Production Units Production units separate crude oil into different fractions or cuts, upgrade and purify some of these cuts, and convert heavy fractions to light, more useful fractions. This area also includes the utilities which provide the refinery with fuel, flaring capability, electricity, steam, cooling water, fire water, sweet water, compressed air, nitrogen, and so on, all of which are necessary for the safe operation of the refinery. 

After hot water extraction, crude bitumen is upgraded into synthetic oil fractions by either delayed coking or fluidized coking. A representative product yield from direct coking of Athabasca oil sand bitumen is provided in TABLE 12-7. 

Several refineries in Europe employ the Pro-Abd refiner to upgrade whizzed naphthalene to phthalic-grade quality or to convert the latter into the purer chemical grade. The device consists of a rectangular tank fitted with a nest of coils through which either steam or water circulates. The tank is filled with the feedstock, which is crystallized by circulating cold water in the coils. When the contents of the tank have solidified, a tap at the base is opened and hot water is circulated until the temperature is just below the desired crystallizing point of the product. This condition is maintained until no more oil drains from the base. The bottom tap is then closed and the contents of the tank are melted by steam circulation and drained. 

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