TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The method comprises:(A) obtaining hardwood, mixture of hardwood, and mixture of softwood;(B) converting wood into wood chips of 0.25-1 inch with thickness of approximately 0.25 inch; saw dust, fines, over sizes, and over thick chips from chipping operation;(C) charging wood chips, at their natural moisture content (40-50%), and up to 5% (on oven-dried weight basis of biomass) acid (sulfuric acid, nitric acid, or hydrochloric) into a pre-soak tank or acid impregnator to achieve a pH of 2-3; residence time can be as long as 4-less than or equal to 5 hours;(D) draining the acid-presoaked chips by centrifuging to remove excess acid and effect a solids consistency of 30-35%; the chips are conveyed and heated in a series of steam/gas mixers with flash steam from the blow tanks and screw fed into a pressurized reactor; direct live steam with(out) inert gas (such as carbon dioxide, air, nitrogen, or oxygen) can be added to raise the reactor temperature and pressure; the reaction is at 150-300degrees C and 150-1000 psig for 1-30 minutes;(E) blowing (releasing) wood chips from the high pressure reactor under high pressure into a series of blow tanks or flash tanks with capacity for holding time disintegrates them into more impregnable lignocellulosic solids for subsequent treatment stages; flash steam are recycled to the pre-heat steam mixers;(F) pressing the solids product from the blow tank to separate the liquor and solids; the solids can be further washed in a series of countercurrent washers to recover the hydrolyzed (hemicellulosic) sugars; the filtrates from the washer contain high concentration of pentose sugars such as xylose, arabinose, or galactose;(G) adding lime to neutralize the pre-hydrolysates to a pH 8-10; this treatment is raised to 40-80degrees C with 30-180 minutes residence time; lime precipitates compounds which could be toxic to fermentation; after liming the prehydrolysate containing sugars from hemicelluloses is sent to a prehydrolysate storage tank ready for fermentation;(H) the washed solids from the pressurized pre-hydrolysis stage containing primarily lignin, cellulose and extractives; lignin from wood species could be highly condensed and difficult to remove; hence, there are two process options for extracting/delignifying the lignocellulosic solids and purify the cellulosic fraction;(I) charging washed lignocellulosic solids into a series of two to four-stage continuous co-current delignification/deresination reactors; in each stage, a 1% to a maximum 10% chemical charge (based on solids) of solution of sodium chlorite/acetic acid anhydrous (may substitute acetic acid anhydrous for peracetic acid, acetic acid, or sulfuric, or nitric acid), or of solution of chemicals such as chlorine/chlorine dioxide, or sodium hypochlorite, and/or acidic hydrogen peroxide are mixed with the incoming lignocellulosic solids in a stock mixer before the reactor; the reactor is at 120-180 F and has a residence time of 3-4 hours;(J) after exiting from the first stage reactor, the solids are separated from the filtrate without washing; the solids are sent to subsequent stages, where fresh solutions of sodium chlorite/glacial acetic acid (anhydrous) are added at the beginning of each stage; process conditions such as temperature, pressure, and residence time in these subsequent stages are similar to the first stage; alternatively, other chemicals such as acidic hydrogen peroxide or chlorine dioxide/chlorine, could be used in place of sodium chlorite/acetic acid anhydrous; the total amount of (oxidant) chemical charges are based on the amount of lignin and extractives, ratio of sodium chlorite to acetic acid anhydrous are 3/1 to 6/1, and the chemicals can be equally distributed or staggered toward the front end, e.g. for a four-stage reaction, a 40% of total chemicals in the first stage reactor, 30% in second, 20% in third, and 10% in the last stage;(K) for the second process option with the less condensed and more easily extracted lignin: the lignocellulosic solids are first extracted with caustic; operating conditions are caustic charge 2-12% on solids, 80-150 F, and residence time 1-3 hours;(L) after caustic extraction, the solids are washed; chlorine/chlorine dioxide (or sodium chlorite/acetic acid anhydrous) are charged (based on the lignin content remained) to delignify/de-resinate and purify the cellulosic solid; chlorine dioxide charge should be 30-50% of the total equivalent chlorine charge; the sequence of chemical application is chlorine dioxide and then chlorine to achieve maximum effect of oxidation; at 80-120 F, residence time is 1-3 hours, solids consistency is 3-10%;(M) after chlorine dioxide/chlorine delignification stage, the solids are washed in a counter-current washer train;(N) the washed solids from the delignification/deresination stage contain primarily cellulose and the washer filtrates contain primarily lignin; the filtrates can be combined with other filtrates containing lignin and other degradation products for evaporation and recovery;(O) the cellulose can be converted to glucose by cellulose enzymatic hydrolysis; or it can be converted directly to ethanol by adding cellulase and yeast or bacteria together;(P) alternatively, a dilute acid hydrolysis stage under moderate temperature can be used to hydrolyze cellulose into fermentable glucose; conversion yield to glucose above 90% is typical with pure cellulose solids;(Q) the two process hydrolysates containing primarily glucose (main hydrolysate) and xylose/arabinose (prehydrolysate) can also be combined and fermented (e.g., with Zymomonas Mobilis, or Schizosaccharomyces Pombe, cellulase, beta -glucosidase, and xylose isomerase) to produce ethanol; or alternatively, these two process streams containing glucose and hemicelluloses sugars can be fermented separately (for higher conversion efficiencies);(R) as an alternative to ethanol, a biofuel, the main product from hemicelluloses and cellulose, the prehydrolysate containing primarily xylose can be converted to furfural or xylytol;(S) process stream containing lignin, can be concentrated and used as a by-product such as drilling mud additive, to produce phenolic chemicals or burn to generate power and steam; and(T) steam and gas from blow tank can be flashed in two or three stages, and flash steam/gases are recycled to preheat the pre-soaked feed into the pressurized reactor. EXAMPLE - The biomass feedstock of hardwood (oak, gum or aspen) sawdust and/or chips (0.25-0.75 inch) at 50-60% moisture content was pre-soaked with an acid solution which was pre-heated to 85degrees C with 30 psig saturated steam for approximately 60 minutes. The acid-soaked feedstock was drained or squeezed to 35% solids. The feedstock was further dewatered to 40-60% solids. The acid-impregnated biomass was fed into the hydrolyzer and steam was injected at 250-280degrees C for 30 minutes. The hydrolysate slurry was discharged at 120-140degrees C for 20 minutes - 2 hours. The hydrolysate solids were washed with warm/hot water at 40-70degrees C, where the water was used in a ratio of 2/1 to 4/1. 12-15% Solids were conveyed to the caustic extraction and delignification/extractive removal stages. The acidic prehydrolysate was neutralized. Alkali (lime or ammonia) was added to the filtrate to have a pH of 5. The solids were washed with fresh hot water. Excess chlorination washer filtrate containing chlorinated lignin, phenols, extractives were mixed with filtrate. The combined filtrates were evaporated. The remaining solid was pure cellulose, free of lignin, wood extractives, and hemicelluloses. Ethanol fermentation was carried out for hemicellulose sugars and cellulose. The pH-adjusted and filtered extract was cooled to 30-40degrees C. Lime or ammonia was added to the hydrolysate slurry to adjust the pH to 4.5. The slurry was cooled to 32-42degrees C, and fed into the top of the fermentor. The fermentation broth was pumped into a beer well. Ethanol was recovered from the beer. The beer column bottom stream was centrifuged to recover suspended solids. The centrifuge cake was further dewatered to approximately 50% total solids.