TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The catalyst is a strong acid, which is hydrochloric acid, where the strength of hydrochloric acid is enhanced by adding inorganic metal chlorides. The metal chloride is iron(III)chloride present in approximately equimolar amounts. Preferred Parameter: The molar amount of catalysts is 0.01-0.2 mole for every 1000 g water and solvent mixture.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The organic solvent is lower alcohol, which is methanol or ethanol; or ketone, preferably acetone.    TECHNOLOGY FOCUS - POLYMERS - Preferred Process: The feed materials are comminuted mechanically to a size that passes through less than or equal to 10 mm screen. The comminuted feed materials are further mechanically degraded by subjecting to an explosive decompression treatment using pressurized carbon dioxide gas. They are compressed by a factor of 6-10 using a feeder screw having a variable pitch and dropped into a pressurized digestor vessel for the first stage of hydrolysis. The first of the series of three hydrolysis stages accomplishes the near complete removal of hemicellulose component of the feed material as small fragments soluble in water, without any added catalyst, that is used as extractant. The first stage of hydrolysis is carried out near 400 K and near 0.3 MPa for 1-4 hours in the pressurized digestor vessel containing water and solid feed material, such that the liquid to solid ratio is 3-5. The feed material that remains after the removal of hemicellulose component in the first stage of hydrolysis exits the pressurized digestor vessel through an extractor screw having a variable pitch after having been compressed by a factor of 6-10. The second of the series of hydrolysis stages accomplishes the near complete removal of lignin component of the feed material as small fragments soluble in the mixture of water and organic solvent, with added catalyst, that is used as extractant. The second stage of hydrolysis is carried out inside a pressurized digestor vessel near 400 K and at 0.5-1.0 MPa for 1-4 hours, where the ratio of weights of the solid contents and the liquid contents is approximately 4-6. The liquid product stream exiting the pressurized digestor vessel is immediately sprayed into a large expansion chamber along with some steam; and the organic solvent is completely removed as vapors, which are distilled, condensed, and reused. The feed material that remains after the removal of lignin component in the second stage of hydrolysis exits the pressurized digestor vessel through an extractor screw having a variable pitch after having been compressed by a factor of 6-10. The compressed residual feed material that exits the extractor screw is first subjected to high-intensity ultrasound radiation by a set of sonicators arranged radially around the mouth of the extractor screw. The energy deposited in the residual feed material as it exits the extractor screw by the sonicators is approximately 10-100 J/g. The compressed residual feed material exiting the mouth of the extractor screw whether subject to the ultrasound treatment or not, enters an expansion chamber, which has a flow of steam through it, which collects the vapors of the organic solvent absorbed by the residual feed material and mixes it with the vapors exiting the expansion chamber, where the expansion chamber also serves as a hopper for a feeder screw that once again compresses the residual feed material and deposits it into an unpressurized digestor vessel. The third of the series of hydrolysis stages accomplishes the near complete removal of cellulose component of the feed material as small fragments soluble in water and with added cellulase enzyme preparation that is used as extractant. The residual undissolved feed material exits the unpressurized digestor vessel through an extractor screw, which has a variable pitch and compresses the residual feed material by a factor of 6-10 before expelling it from the digestor. The residual feed material expelled from the unpressurized digestor vessel is dropped into a biomethanation reactor. All three stages of hydrolysis are carried out in digestors provided with a screw having a variable pitch that pushes the solid forward and compensates for the loss of mass due to dissolution in extractant. The liquid extractant in all three stages of hydrolysis moves in a countercurrent manner past the solid feed material through perforations in the screw flights. The product streams from the first and third stages of hydrolysis are concurrently and separately fermented; and the sugar monomers are converted to ethanol. The ethanol produced is collected by distillation and dehydrated. The product stream from the second stage of hydrolysis after exiting from the expansion chamber is filtered to collect the solid lignin component, which is washed with water and dried. The filtrate is passed through a pressurized thin film evaporator, where sugar monomers are rapidly dehydrated at approximately 475 K and removed from the liquid stream containing dissolved catalyst as vapors, which are condensed and collected. The catalyst solution exiting the pressurized thin film evaporator is reused in the second stage of hydrolysis. The small fragments of hemicellulose in the product stream from the first stage of hydrolysis are further hydrolyzed to form monomers of sugars such as xylose, arabinose, galactose, mannose, and glucose by passing over a solid strong acid catalyst. The small fragments of cellulose in the product stream from the third stage of hydrolysis are further hydrolyzed to form glucose monomers by passing over a solid strong acid catalyst. The ethanol is mixed with solid lignin along with solid strong acid catalyst. The catalyst is filtered off after 30 minutes-1 hour and reused. The filtrate, which is the liquid biofuel, is sent to a storage tank. Preferred Parameter: The mass flow rate of the liquid product stream from the first stage of hydrolysis is 2-3 times the mass flow rate of feed material exiting the pressurized digestor vessel. The ratio of the weights of water and organic solvent is 0.33-1.5. The mass flow rate of the liquid product stream from the second stage of hydrolysis is 2-3 times the mass flow rate of feed material exiting the pressurized digestor vessel. Preferred Component: The solid strong acid catalyst is sulfonated crosslinked polystyrene or sulfonated activated carbon. EXAMPLE - Sugarcane bagasse (50 kg) with a moisture content of approximately 10 wt.% was mixed with water (100 L); and the mixture was loaded into a 500 L stainless steel pressure vessel fitted with a steam jacket. The temperature was raised to approximately 400 K when the pressure inside the vessel reached approximately 0.4 MPa. After 4 hours, the vessel was cooled and the contents were separated into a liquid fraction and a solid fraction using a centrifuge. The solid fraction comprising the residue of the sugarcane bagasse was washed with boiling water (50 L) twice in succession and then air dried, where dry weight of this fraction was 31 kg, 69 wt.%, and the liquid extract (160 L) and contained soluble sugars ( approximately 15 kg). The sugarcane bagasse residue was mixed with extractant liquid (200 L) comprising a mixture of equal volumes of water and acetone to which had been added iron(III)chloride (1.6 kg) and 36 wt.% aqueous, solution of hydrochloric acid (1 L). The mixture was loaded into a 500 L stainless steel pressure vessel fitted with a steam jacket. The temperature was raised to approximately 400 K when the pressure inside the vessel reached approximately 0.9 MPa. After 4 hours, the vessel was cooled and the contents were separated into a liquid fraction and a solid fraction using a centrifuge. The solid fraction comprising residue of sugarcane bagasse was washed first with hot acetone (50 L) and then with boiling water (50 L) and then air dried, where dry weight of this fraction was 19 kg, 42 wt.%, the liquid extract was 260 L, and acetone was recovered by distillation, and where lignin was precipitated and collected by filtration at 8.9 kg, 20 wt.%. The solid lignin was added with anhydrous ethanol (17 L) followed by acetone (4 L). Amberlyst 15(RTM: reusable catalyst) (0.1 kg) was added; and the mixture was stirred for 30 minutes until lignin had dissolved completely. The catalyst was then filtered; and the filtrate was bottled.