Patent ID: 12234494

EXEMPLARY EMBODIMENT 1

FIG.1shows a diagrammatic representation of the method without the production of animal feed, foodstuffs and corn oil. Table 1 shows the composition of the corn meal for this exemplary embodiment. Table 2 shows the mass flow rates for this exemplary embodiment.

Step1: Corn is fed to a dry milling step. The corn has a mass fraction of 60% of particles of less than 0.5 mm and a TS content of 85%.

TABLE 1Corn meal compositionMass fraction ofMass fractionoriginal substance (OS)of TSWater15.00%Starch60.90%71.65%Sugar2.20%2.59%Protein8.10%9.53%Fat3.70%4.35%Lignocellulose8.90%10.47%Ash1.20%1.41%Total100.0%100.0%

Step2: 1.0 t/h of corn meal is mashed with 0.4 t/h of outflow from the biogas unit, 0.8 t/h of whole stillage, 1.6 t/h of thin stillage and 0.46 t/h of process liquid from the ethanol unit and 0.12 t/h of water (for example drinking water). The outflow from the biogas unit, whole stillage, thin stillage and process liquids, has TS contents of 4%, 20.5%, 15% and approximately 0%. Thus, per tonne of corn meal, approximately 0.4 m3of outflow from the biogas unit, 0.16 t TS of whole stillage, and 0.4 t TS of mixed stillage (whole stillage and thin stillage) is fed to the mashing step. The outflow from the biogas unit has a NH4-N concentration of 500 ppm. In this regard, 200 g of NH4-N in the form of outflow from the biogas unit per tonne of corn meal is fed to the mashing step. The pH is adjusted to 4.2 using sulfuric acid and enzymes for digesting the starches are added (not shown inFIG.1and the mass balance of Table 2).

Step3a: The mash from step2is fed to a cooking stage and heated to 60° C.

Step3b: The mash from step3ais cooled to below 30° C. Glucoamylase and yeast are added (not shown inFIG.1and mass balance of Table 2) and starch is converted into ethanol in the fermentation step.

Step3c: The ethanol-containing mash is fed to a distillation step at 67° C. and 0.344 t/h of ethanol is removed from the mash (corresponds to 436 liters per tonne of corn meal). The stream of ethanol is freed from water in further steps and the stream of water is fed to the mashing step as the process liquid. The ethanol-depleted mash, the whole stillage, from the distillation step is fed to the mashing step at 0.8 t/h (step2), to the biogas unit at 0.14 t/h (step5) and to the solid-liquid separation step at 2.3 t/h (step4).

Step4: 2.3 t/h of whole stillage from step3undergoes a solid-liquid separation step in a decanter centrifuge. This produces thin stillage and wet cake. The thin stillage is recycled to the mashing step (step2); the wet cake is fed to the biogas unit (step5).

Step5a: Whole stillage from step3and wet cake from step4and 0.14 t TS/h of wheat straw are fed to the biogas fermenter of the first stage. The outflow from the biogas fermenter of the first stage is fed to the biogas fermenter of the second stage. The outflow from the biogas fermenter of the second stage is fed to the biogas fermenter of the third stage. Biogas is produced in all three stages. 1.3 MW of biogas is formed in the entire biogas unit. The mean hydraulic residence time for the biogas unit as a whole is 70 days.

Step5b: The outflow from the biogas fermenter of the third stage of step5ais fed to a decanter centrifuge of a solid-liquid separation step. Outflow solids are thus formed which are discharged from the biogas unit.

Step5c: The liquid phase from step5bis fed to an ammonia stripping step (ammonium removal). Here, ammonia is removed from the liquid phase and the NH4-N content falls to 500 ppm. The ammonium which is removed is discharged from the biogas unit in the form of ammonium sulfate. 0.4 t/h of outflow with a 500 ppm NH4-N content was fed to the mashing step (step2). A portion of the outflow was recycled to the biogas fermenter in step5a, in order to adjust the NH4-N concentration in the biogas fermenter to 6000-9000 ppm. The concentrations of organic acids and aromatic compounds in the outflow from the biogas unit is a maximum of 150 ppm respectively.

Energy balance: The biogas which is obtained from the biogas unit covers the entire energy requirement for the combined bioethanol and biogas unit. For the fuels produced, this means that the Cl score is significantly improved compared with a typical bioethanol unit. In a typical bioethanol unit, the energy consumptions increase the Cl score by approximately 20-25 gCO2e/MJ.

Water consumption: The freshwater requirement for the unit is only approximately 0.1 m3per tonne of corn meal, which corresponds to a reduction in fresh water by one order of magnitude compared with a typical bioethanol unit.

TABLE 2Mass flow rates for Exemplary embodiment 1tt/hTS/hParametersDry milling (step 1)Corn maize, in~1~0.85Corn meal to step 11.000.85Mashing (step 2)Corn meal from step 11.000.85Biogas unit outflow from step 50.400.02~0.4 m3per t corn mealWhole stillage from step 30.800.160.16 t TS whole stillageper t corn mealThin stillage from step 41.600.24Mixed stillage (whole stillage2.400.400.40 t TS mixed stillageand thin stillage, calculated)(whole stillage and thinstillage) per t corn mealProcess liquid0.46~0Water0.12~0

Exemplary Embodiment 2

FIG.2shows a diagrammatic representation of the method with the production of high added value, protein-rich animal feed and foodstuffs and corn oil.

Step1a: Corn is fed to the ethanol production step. This contains the process steps of dry milling, mashing, fermentation, distillation and solid-liquid separation of a portion of the whole stillage. Process water is fed in the form of blowdown water from the cooling water system and blowdown water from the steam production system, as well as outflow from the biogas unit. The products are ethanol and carbon dioxide, and whole stillage, wet cake and thin stillage as intermediate products.

Step1b: High added value, protein-rich animal feed and foodstuffs as well as corn oil are obtained as products from the thin stillage from step1a. In this regard, “protein-rich” means that the raw protein content (mass fraction of protein in TS) with respect to the thin stillage has been increased using suitable processes. Residual substances are obtained as intermediate products and have a lower raw protein content than the thin stillage.

Step2a: Whole stillage and wet cake from step1aas well as residual substances from step1bare fed to the biogas fermenters. Biogas fermenter outflow as well as biogas are obtained as intermediate products.

Step2b: The biogas from step2ais used for the production of process energy (steam, electricity) and/or are fed to a biogas purification step in which biomethane and carbon dioxide are obtained as products.

Step2c: The biogas fermenter outflow from step2ais fed to an outflow purification step. In a solid-liquid separation step, an outflow solid is produced as a product which, for example, could be used as a high added value fertilizer and soil improver. The liquid phase is fed to an ammonia stripping step in which an ammonium salt, optionally as an ammonium salt solution, is obtained as a product. The ammonium-depleted, liquid phase is fed to an evaporation step in which a nutrient concentrate is obtained as a product which, for example, could be used as a fertilizer. An outflow with a reduced nutrient, ammonium and solids fraction compared with the biogas fermenter outflow is obtained from the condensates from the evaporation step as an intermediate product.

Energy balance: Depending on the quantity of corn oil and animal feed/foodstuffs produced, the biogas produced in the biogas unit may be sufficient to cover the entire energy requirement for the combined ethanol unit and biogas unit. External energy sources might be necessary.

Water consumption: The freshwater requirement for the unit is only approximately 0.1 m3per tonne of corn meal, which corresponds to a reduction in fresh water of about one order of magnitude compared with a typical bioethanol unit.

BIBLIOGRAPHY

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