Sugar from wood-pulping liquors

Refining of Sugar and Recovery of Acetic Acid from Wood-Pulping Liquors... 

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, liquors from the prehydrolysis of wood for kraft pulping, hardboard plants, and hardwood wastes (109). 

Calcium Lignosulfonate occurs as a brown, amorphous polymer. It is obtained from the spent sulfite and sulfate pulping liquor of wood or from the sulfate (kraft) pulping process. It may contain up to 30% reducing sugars. It is soluble in water, but not in any of the common organic solvents. The pH of a 1 100 aqueous solution is between approximately 3 and 11. 

Traditionally, the organic components of expander formulations are derived from natural products such as wood pulp. The composition of such materials is poorly defined. Lignin extracts, frequently obtained from waste sulfite liquors in the papermaking industry, are purified by removing sugars and various metals, and then depolymerized to different degrees. Lignin molecules are formed from three primary precursors, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol the... 

Calcium carbonate scale is even more commonplace in Kraft pulp mill systems such as heat exchangers, where, compared to paper machines, it often forms a thick deposit leading to loss of performance of the heat exchanger. Calcium comes into the system with either the wood or from poor recovery liquor clarification and carbonate is formed from degradation of sugars in a side reaction during pulping conditions. Dissolution of filler (calcium carbonate) will increase the concentration of both calcium and carbonate in the system. 

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). 

Xylose Modified Phenol-Formaldehyde Resins. Xylose (I) and byproducts streams containing xylose (e.g., wood prehydrolysates from the production of chemical pulps and waste liquors from the wet process for hardboard production) are readily available. Our previous experiments (2) showed that free reducing sugars are not acceptable modifiers for phenol-formaldehyde resins cured under basic conditions. 

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