https://faculty.washington.edu/renatab/courses/PSE490/downloads/pretreatment.pdf

Features of promising technologies for pretreatment of lignocellulosic biomass.

Biofuels produced from various lignocellulosic materials, such as wood, agricultural, or forest residues, have the potential to be a valuable substitute for, or complement to, gasoline. Many physicochemical structural and compositional factors hinder the hydrolysis of cellulose present in biomass to sugars and other organic compounds that can later be converted to fuels. The goal of pretreatment is to make the cellulose accessible to hydrolysis for conversion to fuels. Various pretreatment techniques change the physical and chemical structure of the lignocellulosic biomass and improve hydrolysis rates. During the past few years a large number of pretreatment methods have been developed, including alkali treatment, ammonia explosion, and others. Many methods have been shown to result in high sugar yields, above 90% of the theoretical yield for lignocellulosic biomasses such as woods, grasses, corn, and so on. In this review, we discuss the various pretreatment process methods and the recent literature that...

http://ucce.ucdavis.edu/files/datastore/234-1388.pdf

Methods for Pretreatment of Lignocellulosic Biomass for Efficient Hydrolysis and Biofuel Production

Industrial applications of microbial lipases

Trends in bioconversion of lignocellulose: Biofuels, platform chemicals & biorefinery concept

Cellulases and related enzymes in biotechnology

The pulp and paper industry ranks third in terms of water consumption and fifth among the major industries in its contribution to water pollution problems in the USA. Pulping, bleaching, and paper-making operations are the three major wastewater sources of the industry.

Decolorization and Detoxification of Bleached Kraft Effluents

Chemical additives used in papermaking fall into three groups—general (commodity) and two classes of specialty chemicals—process and functional. Process chemicals are used to optimize the production process by increasing machine speed, runnability, providing deposit control and reducing steam consumption. Retention aids, defoamers, fixative agents, biocides, and defoamers/antifoam additives are some typical examples of process chemicals. Functional chemicals directly affect paper quality and paper properties—color, water repellency, strength, printability, etc. Typical examples of such functional chemicals are dyes, coating binders, and strength and sizing additives. The boundary between process and functional chemicals is not very definite as process chemicals may either significantly influence performance of functional chemicals and/or affect sheet properties directly. About 90% of all chemical additives belong to functional additives. The remaining 10% are process chemicals, with retention aids (including fixatives, coagulants, flocculants and microparticles) representing the biggest and most important part. The in-depth and thorough coverage of chemical additives in the pulp and paper industry are presented. Various sections deal with pulping chemicals, bleaching chemicals, process chemicals, functional chemicals, pigments for fillers, coating pigments, aluminum, starch, chemicals used in paper recycling, and chemicals used for stickies control and tissue and towels.

Pulp and Paper Chemicals

Black liquor gasification (BLG) is being considered primarily as an option for production of biofuels in recent years due to the focus on the transport sector’s high oil dependence and climate impact. BLG may be performed either at low temperatures or at high temperatures, based on whether the process is conducted above or below the melting temperature range of the spent pulping chemicals. The development of various BLG technologies—SCA-Billerud process, the Copeland recovery process, Weyerhaeuser’s process, the St. Regis hydropyrolysis process, the Texaco process, VTT’s circulating fluidized bed BLG process, Babcock and Wilcox’s bubbling fluidized bed gasification process, NSP process (Ny Sodahus Process), DARS (Direct Alkali Recovery System) process, BLG with direct causticization, Manufacturing and Technology Conversion International fluidized bed gasification, Chemrec gasification, catalytic hydrothermal gasification of black liquor—is discussed in this chapter. The two main technologies under development are pressurized gasification and atmospheric gasification, being commercialized by Chemrec AB and ThermoChem Recovery International, respectively.

Black Liquor Gasification

Several countries have introduced or are introducing programs for fuel ethanol. According to RFA, Brazil and the US are the dominant industrial players, accounting for 87 % of global biofuel production driven by government support.

Global Production of Bioethanol

The Minimum Impact Mill Technologies which can meet the environmental challenges of the pulp and paper industry are discussed in this chapter. These include Optimised wood handling; Dry Debarking; High Yield Pulping Process; Extended Modified cooking; Efficient Brownstock Washing/Improved Pulp Washing; Oxygen Delignification; Ozone bleaching; ECF and TCF bleaching; Fortification of extraction stages with oxygen and hydrogen peroxide; HexA Removal; Condensate Stripping and Recovery; Minimum SO2 and NOx Emissions; Electrostatic Precipitators; Increase in the dry solids content of black liquor; Installation of scrubbers on the recovery boiler; Incineration of odorous gases in the lime kiln; Installation of low NOx technology in auxiliary boilers and the lime kiln; SNCR on bark boilers; Over Fire Air Technique on recovery boilers; Installation of improved washing of lime mud in recausticizing; Efficient Primary, Secondary and Tertiary Waste Treatment (in some special cases); Partial system closure; Minimum Power Consumption; Waste water Recycling and reuse.

Pratima Bajpai

Papers

Decolorization and Detoxification of Bleached Kraft Effluents

Pulp and Paper Chemicals

Black Liquor Gasification

Global Production of Bioethanol

Minimum Impact Mill Technologies