초록 ▼

A method for producing ethanol starting from corn flours, which provides for the milling of the corn, the separation of the light fractions (bran), a first refining of the milled fractions, a first sifting with germ separation, a second refining of the milled fractions, and a second sifting with ger

A method for producing ethanol starting from corn flours, which provides for the milling of the corn, the separation of the light fractions (bran), a first refining of the milled fractions, a first sifting with germ separation, a second refining of the milled fractions, and a second sifting with germ separation. In particular, according to the invention, impact milling of the wet corn is provided so as to preserve the largest possible average particle size of the milled fractions, and subsequent crushing of the germ is also provided, so as to facilitate size separation thereof. With respect to known systems for producing ethanol starting from corn flours, the method according to the invention allows to extract from corn at least 7%, preferably at least 10% (by weight with respect to the initial product) of pure germ (i.e., germ not contaminated by other components) and at least 1% pure bran, preferably at least 2.5%, before transfer to the ethanol extraction plant, with the previously cited consequent advantages and overcoming the drawbacks that arise from using the systems that constitute the background art. In particular, the extraction from corn of at least 7% of the germ, preferably at least 10%, and of at least 1% bran, preferably at least 2.5%, allows to achieve drastic reductions in the production of pasty residues in the subsequent ethanol extraction process.

대표청구항 ▼

The invention claimed is: 1. A method for producing ethanol from corn flour, comprising preparing the corn flour and subsequently extracting ethanol from the prepared corn flour, the preparing of the corn flour comprising: impact milling corn grain; separating the impact milled corn grain into a fi

The invention claimed is: 1. A method for producing ethanol from corn flour, comprising preparing the corn flour and subsequently extracting ethanol from the prepared corn flour, the preparing of the corn flour comprising: impact milling corn grain; separating the impact milled corn grain into a first stream of light fractions and a second stream of germ, grits and residual bran; refining said second stream to produce refined germ, grits and residual bran; sifting the refined germ, grits and residual bran to separate germ and grits from one another, the sifting producing an intermediate product including germ, grain and residual bran; refining the intermediate product; and sifting the refined intermediate product to separate germ and grits from one another. 2. The method according to claim 1, wherein said impact milling is carried out on wet corn grain, so as to preserve a largest possible average particle size of milled fractions in said second stream, with separation of the bran by friction. 3. The method according to claim 2, wherein the refining of said second stream includes crushing of the germ, so as to facilitate its size separation. 4. The method according to claim 1, wherein said impact milling is carried out using an impactor. 5. The method according to claim 4, wherein said impactor has moving blades, having an impact surface, relatively large with respect to the other dimensions of the blades; said impact surface moving substantially perpendicular to a moving direction of said blades. 6. The method according to claim 5 in which said blades move at a speed lower than 70 m/s. 7. The method according to claim 6 in which said blades are mounted on a rotor and extend from the rotor at least 30 mm. 8. The method according to claim 1, wherein throughs in output from said impact milling are sent to a rotary separator, which separates the grits from the throughs and a corresponding reject. 9. The method according to claim 8, wherein said impact milling produces a reject stream is sent to a first separator, from which said first stream of light fractions and said second stream of grits, germ and residual bran exit, said second stream being subsequently sent to a station for wetting with water and to a first roller mill, in which the germ is crushed, so as to facilitate subsequent size separation of germ and grits in a sieve, the sifting of the refined germ, grits and residual bran and the producing of said intermediate product taking place via said sieve. 10. The method according to claim 9, wherein said intermediate product in output from the sieve is added to the reject from the rotary separator and is passed through an additional separator, from which a third stream of light fractions and a fourth stream of grits, germ and minor amounts of residual bran exits. 11. The method according to claim 10, wherein said fourth stream is sent to a second roller mill, in which additional crushing of the germ in said fourth stream is performed so as to facilitate subsequent size separation in an additional sieve. 12. The method according to claim 11, further comprising, in output from said additional sieve, an output of germ as a finished product, an output of grits as a finished product, and an output of additional intermediate product, in which the germ outputs, which arrive respectively from the sieves, are conveyed to a yet another separator, from which a stream of light fractions and a stream of germs separate. 13. The method according to claim 9, wherein the refining of said second stream generates an additional light fraction stream, further comprising conveying said first stream and said additional light fraction stream to a pneumatic settling unit, from which a first output for bran and any fine grits fractions and a second output of dusty air lead out, also comprising conveying said air in turn into a manifold to be sent to a bag filter. 14. The method according to claim 13, wherein said first output leads to a rotary separator, which divides the bran and fine ants fractions of said first output into a grits output and a corresponding waste formed by bran, grits in the dusty air of said second output being further separated in said filter. 15. The method according to claim 5 in which said blades move at a speed lower than 35 m/s. 16. The method according to claim 6 in which said blades are mounted on a rotor and extend from the rotor at least 60 mm.