Hulls, rice

Tluid-hed reactor rice hulls process heat... 

Some common flake-shaped LCMs consist of shredded cellophane and paper, mica (qv), rice hulls, cottonseed hulls, or laminated plastic. These materials He flat across the opening to be sealed or are wedged into an opening such as a fracture. Some are sufficiently strong to withstand considerable differential pressure, whereas others are weak and the seal may be broken easily. Weaker flake materials typically are used near the surface or in combination with fibrous or granular additives. 

In the United States, up to about 4 x 10 Btu/yr of biofuels ate consumed for electricity generation, raising process heat, and domestic heat. Eurthermore, much of the energy needs of many nations are met by biofuels, including wood and wood waste, spent pulping fiquors, bagasse, and municipal waste. Some use is also made of dried com cobs, rice hulls, and a wide variety of agricultural wastes used in niche appfications. 

In one modification of this procedure, the starting material is pyroly2ed rice hulls in place of more conventional forms of sihcon dioxide (31). Another unique process involves chlorination of a combination of SiC and Si02 with carbon in a fluid-bed reactor (32). The advantages of this process are that it is less energy-intensive and substantially free of lower sihcon chlorides. 

P. K. Basu, Ph.D. dissertation, Depelopment of a Processfor the Manufacture of Silicone Tetrachloride from Rice Hulls, University of California, Berkeley,... 

Industrial by-products are becoming more widely used as raw materials for cement, eg, slags contain carbonate-free lime, as well as substantial levels of silica and alumina. Fly ash from utility boilers can often be a suitable feed component, because it is already finely dispersed and provides silica and alumina. Even vegetable wastes, such as rice hull ash, provide a source of silica. Probably 50% of all industrial by-products are potential raw materials for Pordand cement manufacture. 

Nonpowder Synthesis. Many ceramic composites (qv) under iavestigation utilize reinforcing ceramic whiskers or fibers to achieve toughening (19). Whiskers (17,19,20) are produced by vapor-synthesis techniques. SiC whiskers can be produced by the rice hull or vapor—soHd (VS) method whereby rice hulls are pyrolyzed to produce a mixture of carbon, C, and Si02, and whiskers are produced by directional growth by vapor... 

Screw presses (Fig. 2) do not produce a clear liquid product. Frequendy, the product is further filtered in a filter press to give a clear Hquid product. Press aids are added to feed materials containing fine particles or particles that can deform and plug the slots in the edge of a screw press. Typical press aids include sawdust, rice hulls, perlite, and diatomaceous earth (see Diatomite). A vertical screw press is a continuous press that has been used for dewatering sewage sludge (2). 

However, this mode of flow usually is limited to conveying distances of L < 500 m. The Group D materials that possess wide size distributions (especially a considerable amount of fines) and/or unusual particle shape (e.g., crushed coal, petroleum coke, crushed bath, rice hulls) usually are not suited to low-velocity conveying. In these cases, the options are dilute-phase or single-slug dense-phase (i.e., these materials usually are too coarse for bypass conveying). However, when long distances are involved, dilute-phase may be the only practical option. 

Isotope Observation Whole rice Hulled rice Hull Reference... 

A source of fly ash particulates is the mineral matter in the biomass feedstock. As material is gasified, the inorganic matter from the feedstock may be either retained in the gasifier bed or entrained in the product gas and swept out from the reactor. The mineral concentrations in clean wood are typically 1 to 2%, and herbaceous crops may contain up to 10% or more. Crop residues such as straw or rice hulls typically contain 15 to 20% inorganic material. Mineral matter... 

Wood and wood waste includes residues from the forest and the mill. Bark, sawdust and other mill wastes are all suitable fuels. Agricultural residues include corncobs, sugar cane bagasse (the stalks after processing), leaves, and rice hulls. MSW materials include paper products, cloth, yard wastes, construction debris, and packaging materials. 

Adipic acid can also be made from THF, obtained from furfural. It is carbonylated in the presence of nickel carbonyl-nickel iodide catalyst. Furfural is a chemurgic product obtained by the steam-acid digestion of corn cobs, oat hulls, bagasse, or rice hulls. 

Decarbonylation. Furfural is easily obtained from biomass waste such as oat and rice hulls that are rich in pentosans. Further valorisation of furfural can be done by decarbonylation to produce furan, which can be further converted into tetrahydrofuran by catalytic hydrogenation. 

Osawa, T., T. Narasimhan, S. Kawakishi, M. Namiki, and T. Tashiro. Antioxidative defense systems in rice hull against damage caused by oxygen radicals. Agr Biol Chem 1985 49(10) 3085-3087. 

Iowa. Modem industrial prepns start with agricultural residues such as oat hulls, corn cobs, rice hulls, bran, etc, which have a relatively high pentosan content (Ref 10). In these processes pentosans are hydrolyzed to pentoses by acid digestion, and these split out water internally to form forfurals ... 

Sharp silica sand is used as a filler in resinous cement mortars and to provide an abrasive surface in polymers. Reactive silica ash, produced by burning rice hulls, and a lamellar filler, novaculite, which is obtained from the novaculite uplift in Arkansas, are also used as silica fillers in polymers. 

Furan is synthesized by decarbonylation of furfural (furfuraldehyde), which itself can be prepared by acidic dehydration of the pentose sugars found in oat hulls, corncobs and rice hulls. 

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