NOVELTY - An internal circulation process for forming concentrated sulfuric acid catalyzed cellulosic ethanol without pre-treatment involves crushing; liquefaction; hydrolysis; neutralization; separation; fermentation; and distillation, where cellulose is converted into glucose. The time for liquefaction and saccharification is 6-12 hours. The catalyst sulfuric acid and neutralizing agent lime are recycled. The process for using lignin is separation; drying; destructive distillation; reduction; dust extraction; and reduction of sulfuric acid so that lignin becomes fuel gas, tar and lignin carbon.    USE - As internal circulation process for producing concentrated sulfuric acid catalyzed cellulosic ethanol without pre-treatment (claimed).    ADVANTAGE - The conversion rate is more than 90%. 5 Tons of materials containing 40% of cellulose can produce 1 ton of alcohol without pre-treatment. About 99.5% of catalyst is recycled. The reduction carbon self-sufficiency rate is more than 80%; and the method significantly reduces the catalyst cost and saves more than 30% of energy. The method recycles the sulfuric acid and lime, comprehensively utilizes the lignin, forms an internal circulation system of wood fiber-sulfuric acid-calcium oxide lignin carbon, has a catalyst recovery rate of 99.5% and a reduction carbon self-sufficiency rate of greater than 80%, reduces 30% of energy consumption, and provides a foundation for industrial and commercial production of cellulosic ethanol. The co-precipitation has the advantage to be excellent in filtration performance of the precipitate mixture.    DETAILED DESCRIPTION - An internal circulation process for producing concentrated sulfuric acid catalyzed cellulosic ethanol without pre-treatment involves crushing raw materials; liquefaction; hydrolyzing liquefied paste; followed by neutralization; separation; fermentation; and distillation, where the cellulose can be efficiently converted into glucose. The conversion rate is more than 90%. 5 Tons of materials containing 40% of cellulose can produce 1 ton of alcohol without pre-treatment. The time for the whole liquefaction and saccharification is 6-12 hours. The catalyst sulfuric acid and neutralizing agent lime are recycled, meanwhile, the procedure for comprehensively utilizing the lignin is separation; drying; destructive distillation; reduction; dust extraction; and reduction of sulfuric acid, so that the lignin becomes fuel gas, tar and lignin carbon. The lignin carbon is used as a reducing agent of calcium sulfate. The hexavalent sulfur is converted into sulfur dioxide for regenerating sulfuric acid so as to form an internal circulation system of wood fiber-sulfuric acid-calcium oxide lignin carbon. The liquefaction is performed by using a colloid mill or homogenizer to increase the liquefaction efficiency and effect, where the specific measures are as follows: stirring the metered crushed materials with 72% of concentrated H2SO4 for 0.1-0.5 hours, fully moisturizing them for 2 hours, then putting the mixture into the colloid mill or homogenizer, converting more than 90% of the difficultly reacting crystalline cellulose into glucose at a high pressure, regulating pH of the sugar liquid to 3.8 with sulfuric acid, adding nitrogen phosphorus potassium nutrients, fermenting the mixture by Saccharomyces cerevisiae to produce wine, producing absolute ethyl alcohol by a mature method, recycling the yeast by micro-filtration of the distillation waste liquid, and recycling water by reverse osmosis recycled water. In the neutralization step, quick lime and sulfuric acid generate calcium sulfate precipitate in hydrolysate of un-separated lignin to precipitate together with the lignin. The filter separation and affination can be performed by a disc filter device while the mixture is hot, and it is more important that the lignin in the mixture has entered into the regenerative cycle of the sulfuric acid. The drying step involves putting co-precipitate (mixture of lignin and calcium sulfate) obtained in neutralization into a drying furnace for being dried into powder at 150+/-25 degrees C and being blown to the destructive distillation; blowing the dry solid powdery mixture into a retort for being destructively distilled for 10-20 minutes at 400+/-50 degrees C; destructively distilling the mixture and cooling to obtain gas (10%) as the fuel; deeply processing the tar and aqueous solution (about 35%) to obtain light oil and acetic acid etc., where the solid powdery residue is a mixture of lignin carbon (55%), calcium sulfate and calcium sulfide, and is a raw material of the next step for reduction. The reduction step involves oxidizing and reducing the obtained solid powdery residue (comprising calcium sulfide, calcium sulfate and lignin carbon) obtained by destructive distillation, supplementing about 0-20% of coke powder (which can save 80-100% of reduction carbon) to the powdery slag from a retort cyclone separator, blowing them to a fluidized bed roaster, performing ventilation and reduction at 700-900 degrees C, oxidizing and reducing the sulfur element of the calcium sulfide and calcium sulfate into sulfur dioxide gas, catalyzing and oxidizing the SO2 after performing dust extraction by a standard chemical method to generate sulfuric acid, recycling the sulfuric acid to prepare the catalyst sulfuric acid, recycling the calcium oxide powder obtained by separation of the cyclone separator into the neutralization for neutralizing the sulfuric acid in the hydrolysate. The destructive distillation procedure and the redox procedure are carried out in different temperature regions of a fluidized bed furnace.    DESCRIPTION OF DRAWING(S) - The figure shows flow diagram illustrating internal circulation process for producing concentrated sulfuric acid catalyzed cellulosic ethanol without pre-treatment.