Ethanol wood pulping

Alcell [Alcohol cellulose] A process for delignifying wood pulp by dissolving it in aqueous ethanol at high temperature and pressure. Developed by Repap Technologies, United States. 

Propionic acid can be obtained from wood pulp waste liquor by fermentation. It can also be prepared from ethylene, carbon monoxide and steam from ethanol and carbon monoxide using boron trifluoride catalyst from natural gas or as a by-product in the pyrolysis of wood. Very pure propionic acid can be obtained from propionitrile. Propionic acid can be found in dairy products in small amounts. 

Extraction of lignocellulosic materials and biomass CO2, SO2, N2O, H2O, methylamine, ethanol, ethylene Cellulose or ligno-cellulosic materials from wood or wood pulp... 

Large amounts of adhesive mixtures, mainly based on potato or com (maize) starch (with plant varieties grown specifically for the purpose), are employed in paper coating, where the adhesive provides a bond between the fibrous (wood-pulp based) stmcture of the paper and the white china-clay-based surface layer, which can be printed. To improve performance in printing processes, these surface layers are often blended with wood rosin-based products and with polyvinyl alcohol of synthetic origin. Polyvinyl alcohol in adhesives (and its precursor polyvinyl acetate) can be made from ethanol obtained by the fermentation of starch - and once were so made - but the processes, carried out in dilute aqueous solution, are immensely wasteful of thermal energy. 

Chloroform is produced by reaction of chlorine with ethanol and by the reduction of carbon tetrachloride with moist iron. It was once used as a general anesthetic in surgery but has been replaced by less toxic, safer anesthetics, such as ether. Chloroform is produced as a byproduct of water, sewage, and wood pulp chlorination. 

Although the hydrolysis of wood to produce simple sugars has not proved to be economically feasible, by-product sugars from sulfite pulping are used to produce ethanol and to feed yeast (107). Furthermore, a hemiceUulose molasses, obtained as a by-product in hardboard manufacture, can be used in catde feeds instead of blackstrap molasses (108). Furfural can be produced from a variety of wood processing byproducts, such as spent sulfite Hquor, bquors from the prehydrolysis of wood for kraft pulping, hardboard plants, and hardwood wastes (109). 

Wood contains a small proportion (usually less than 5%) of components which are extractable by organic solvents such as ethanol or dichloromethane. The proportion of these extractives varies in hardwoods and softwoods and also between species. Although many of these substances are removed during the chemical pulping process, some may still be retained in the final sheet of paper. Their chemical composition is very varied, and they include alkanes, fatty alcohols and acids (both saturated and unsaturated), glycerol esters, waxes, resin acids, terpene and phenolic components. The proportion which remains in pulp and paper depends upon the pulping process used. In general, acidic components such as the resin and fatty acids are relatively easily removed by alkali by conversion to their soluble... 

Biomass can generate energy in many different forms. Refuse derived fuels (MSW) can produce steam or electric power. They can also be converted to other fuels using chemical or biological processes producing ethanol or methanol. The wood and pulp industries use their wastes to provide a significant part of their heat, steam, and electricity needs. 

The situation with regard to ethanol is much clearer there is long industrial experience in the manufacture of ethanol from wood, by fermentation of the sugars in the waste effluents of pulp mills, or of the sugars made by wood hydrolysis ( ). In the years following World War II, wood hydrolysis plants have been unable to compete economically with petroleum-based ethanol synthesis, mainly by hydration of ethylene, and they have been shut down in most countries. However, in the Soviet Union, we understand, there are still about 30 wood hydrolysis plants in operation (10). Many of these are used for fodder yeast production (11) but the wood sugars are also available for ethanol production. 

Alcohol recovery from the fermentation brews was less than complete in most cases, which may be attributable to less than ideal conditions. The best yields, 60 to 97% of theory, were obtained with sugars obtained by hydrolysis of cellulosic residues of the autohydrolysis-extraction process. Unextracted pulps, or the hemicellulose solutions, gave poor ethanol formation, which suggests inhibition. In the calculation of material and energy balances which follows, we have assumed 95% yields of ethanol from wood sugars, which is readily achieved in industrial practice and which we believe to be achievable with our wood sugars as well. 

Two broad areas of application for xylanolytic enzymes have been identified (1). The first involves the use of xylanases with other hydrolytic enzymes in the bioconversion of wastes such as those from the forest and agricultural industries, and in the clarification and liquification of juices, vegetables and fruits. For these purposes, the enzyme preparations need only to be filtered and concentrated as essentially no further purification is required. Several specific examples of applications involving crude xylanase preparations include bioconversion of cellulosic materials for subsequent fermentation (2) hydrolysis of pulp waste liquors and wood extractives to monomeric sugars for subsequent production of single cell protein (3-5). Xylose produced by the action of xylanases can be used for subsequent production of higher value compounds such as ethanol (6), xylulose (7) and xyIonic acid (8-9). 

In all reactions, wood of white fir Abies concolor) has been used. For the alkaline nitrobenzene reactions, extractive-free —20+40 mesh heart-wood sawdust containing 28.0% Klason lignin was used. Sequential extraction of the original sawdust with alcohol-benzene, 95% ethanol, and hot water gave extractives amounting to 4.9, 0.5, and 1.2%, respectively. In the other oxidation reactions, nominal 5 -in. wood chips, commonly used in pulping procedures, were employed. The mixed sap wood-heart-wood chips contained 26.5% Klason lignin and sequential extractives of 3.3, 0.5, and 3.2%, respectively. 

Preliminary Remarks. The material to be hydrolyzed should be in a milled or pulverized condition or reduced to minute pieces. Wood and pulp samples should be extracted with ethanol-benzene and ethanol according to TAPPI-Standard T6m-59. Each method described below can be applied to 2-50 mg of material. The evaporator for removing the TFA should be kept in a hood. Contact of the acid with skin and eyes must be avoided. 

Methoxylation of TMP samples was achieved by heating pulp fibres together with appropriate amounts of dimethyl sulphate in an equivolume solvent of water, ethanol and dimethoxyethane(74), methoxyl content of the pulp fibres being controlled by the amount of dimethyl sulphate added (Schmidt, J.A. Heitner, C. J. Wood Chem. Chem. Technol., In Press). Samples were analysed for methoxyl content by Scharwzkopf Microanalytical Laboratories, Woodside, New York. Analysis of the TMP samples for phenolic hydroxyl content was according to the method of Gellerstedt and Lindfors(76). 

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