DEEP PROCESSING IS THE PRODUCTION OF PRODUCTS WITH ADDED VALUE.
We will transfer the bioethanol plant with molasses to the grain scheme of raw materials.
We will help you understand what exactly will be the best solution for recycling.
We will calculate and design, build and run technological lines for additional profit.
Products made from corn and wheat are the basis for 90% of food products.
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You can receive:
- Glucose-fructose syrup
- Wheat starch
- Glucose monohydrate
- Wheat and corn gluten
- Corn oil
DRY DEDERMINATION (FRACTIONATION) OF CORN
Dedermination (separation of corn embryos from grain) is carried out in two ways: dry, used in mill-cereal enterprises and food concentrate plants, and wet, common in starch-treacle plants.
The dry dedermination technology includes the following main stages:
- Grain cleaning;
- Controlled hydration up to 18… 20%;
- Rough grinding;
- Separation of the embryo, endosperm particles and husks.
With controlled moistening, the embryo absorbs water in the first place, and after that it is quite easily separated from the endosperm with rough crushing in a special mill – a deatherizer. It is important to maintain a given moisture content of the grain, on the one hand to avoid waterlogging of the endosperm, on the other – to ensure the purity of the embryo from starch. Endosperm residues that have not separated from the embryo reduce its technological qualities for subsequent pressing and oil production and lead to starch losses for ethanol production.
What are the advantages of corn dedermination over bioethanol processing?
Firstly, the preparation of wort receives more starchy raw materials, and this allows to reduce the consumption of diluting enzymes, increase the concentration of brew, reduce the formation of protein contaminants of the heat exchange surfaces and plates of the brew column. The amount of suspended matter in the bard is reduced, the consumption of thermal energy for drying the bard sediment and evaporation of the clarified bard is reduced (almost 80% of the clarified bard is directed to the preparation of kneading).
Secondly, the resulting bard sediment is a more valuable feed product. It is called HP DDG – High Protein DDG, a high-protein DDG. Its main advantage is its high protein content – about 50% (DDGS – up to 30%). For feeding cattle, it is more valuable due to its low phosphorus content (0.32% in HP DDG and 0.9% in DDGS). It is also more suitable for feeding lactating cows, pigs and poultry due to reduced fat content (6% in HP DDG and 10% in DDGS).
Thirdly, it becomes possible to obtain corn oil, more expensive than sunflower and soybean oil, when processing the embryo.
For a plant with a capacity of 100 thousand tons of bioethanol per year, the possible volume of oil production is 4000 tons. Germ cake and husk are also valuable feed products.
Since corn husk forms up to 10% of the volume of processed grain, it can serve as a raw material for various highly profitable products, such as food xylitol.
Grain plan of bioethanol production
PREPARATION AND CRUSHING OF GRAIN RAW MATERIALS
Consider the process of preparing grain raw materials and its subsequent processing into bioethanol by dry grinding corn grains. Corn comes to production from intermediate silos designed for the daily volume of processing.
Usually, the developers of the technology put forward the following requirements for the quality of corn (content in the mass of grain,%) supplied to production:
Starch content (min) 62
Humidity 14
Dry matter 86
Fat 4,6
Protein 10
Fibers 2,2
Ash 1,3
Impurities (organic,
inorganic, other seeds
and residuals) < 1
Other components 4,9
The main task of preparing grain raw materials for crushing is its purification from impurities. It is clear that it is possible to process less quality raw materials, but in this case the developer does not guarantee the achievement of the declared technological indicators.
To ensure the normal operation of grain crushers and the required quality of grinding, the grain is subjected to control cleaning of non-magnetic and magnetic impurities. The requirement for grinding is the passage of 100% of cereals through a 0.8 mm sieve. Some technology developers require that the particle size does not exceed 0.6 mm. Only under this condition it is possible to achieve a sufficient depth of fermentation and ensure the normal operation of heat exchangers without clogging.
Grain from storage is fed into intermediate silo. With a conveyor, grain from the silo is transferred to a grain cleaning machine; wastes are removed into collector, and cleaned grain is fed with norium into intermediate hopper. Through magnetic separators, the grain enters the crushers, from where the grinding through the hopper is fed to the preparation of kneading. At the crushing site, the grain is weighed before being fed to the crushers, and the grinding supplied for kneading is also weighed. All areas are equipped with aspiration systems that exclude pollination.
For grinding grain, hammer crushers are usually used as the most simple and reliable in operation. Sometimes, to prevent excessively large particles from entering the mill, screens of various designs are installed after the crushers, the output of which is returned to crushing.
Thorough grain cleaning at the bioethanol plant will prevent contamination with unwanted microflora and clogging of pipelines and heat exchangers, wort preparation sites, yeast generation and fermentation.
PREPARATION OF WORT.
Grinding from the raw material cleaning and crushing section is continuously weighed and supplied to the intermediate hopper of the wort preparation section. In this area, the grinding is mixed with warm water (kneading), liquefying, then acetic enzymes are added to the kneading, the wort is cooled to the fermentation temperature and transferred to the yeast generation and fermentation (fermentation) sites.
Grinding with norium and a conveyor is fed into a vat of kneading, where heated process water, condensates, luther water and clarified bard enter. The proportions in which these liquids are mixed before being fed to the batch vat are determined by the developers of the technology. Sometimes, for the preparation of kneading, all acidic condensates are used from the evaporation of clarified bard and luthern water, previously neutralizing them with ammonia water to a pH of 4.5… 5. This approach completely eliminates the discharge of acid condensates and Luther water into the wastewater and provides nitrogen nutrition for yeast. For the preparation of kneading, up to 40% (sometimes more) of clarified vinasse is also used after the release of the sediment. In this case, a neutralizing agent (alkali) is added to the kneading liquid through dispensers.
Preparation of kneading is accompanied by an increase in its viscosity, so a number of technological operations called liquefaction are required.
The increase in viscosity is mainly due to the swelling and gelatinization of starch and other polysaccharides (pentosans). Swelling grain proteins also contribute. To prevent this phenomenon, enzyme preparations are used that dilute the kneading.
In general, to ensure dilution, the following enzyme preparations are added to the mixture:
- α-amylase for destruction of starch structure and its dextrinization;
- ß-glucanase for the hydrolysis of ß-glucan present in barley;
- xylanase for hydrolysis of wheat and rye pentosans;
- protease for protein hydrolysis
Amylase is used for liquefaction of kneads from all types of grain. Preparations reducing the viscosity caused by pentosans are used only during the processing of wheat, rye, oats, triticale or barley, but not corn.
The proportions of mixing the grinding and liquid are calculated depending on the possible strength of the brew and the starch content in the grinding. Now, for the use of new yeast races, the concentration of alcohol in mature brew can be obtained up to 18% vol. Developers usually guarantee lower concentrations – 12… 15%. To achieve high concentrations of ethanol in mature brew, the dry matter content in the kneading must be about 28… 34%.
From the vat, the kneading can be supplied for boiling to the contact heater (jet cooker) and then to the aging tank, cooler and icing.
Acidification of rarefied kneading is carried out with the help of glucoamylase preparations hydrolyzing dextrinino maltose and glucose, which are fermented by yeast.
Usually, the kneading is heated to a temperature of 40-50 °C by mixing the grinding with hot water. When preparing the batch, amylase is added to it, and then heated with sharp steam in a steam-contact heater to a temperature of 80… 90 °C, and sometimes more than 100 °C. Kneading is kept at high temperature for some time (depends on the type of raw material, temperature, degree of grinding and the brand of enzyme preparation used). For further acidification, in order to avoid inactivation of glucoamylase, the batch mostly needs to be cooled to 55… 60 °C. After icing for 20-30 minutes, sweet wort is cooled again to the so-called fold temperature – the temperature at which the wort is transferred to fermentation (26-28 °C). This process is depicted in the graph as a solid line.
Wort is heated not above 55… 56 °C to avoid gelatinization, do not spend steam on its heating and water on cooling to 60 °C. Such a process reduces the energy consumption of bioethanol production up to 15%.
The question arises how it is possible to avoid the development of contaminating microflora in wort and brew, since the raw material does not even heat up to the pasteurization temperature? The developer of the technology, Agrotechnologie, uses acid-resistant amylases and conducts the process of liquefaction and acidification at low pH values, which allows reliable antiseptic of the wort.
After holding the kneading in the vat, the wort is acidified, fed to the heat exchanger-cooler and enters the icing tank for subsequent icing at a temperature of 55… 60 °C. Glucoamylases must be added to the wort before being fed to the acetic acid, it is recommended to add cellulases and, if necessary, proteases and other preparations depending on the type of raw material.
ICING.
The area of icing is technologically solved in different ways. Complete curing of starch before fermentation is used by Agrotechnologie in its projects. Sometimes the volume of acetic acid “implies a minimum residence time of the liquid (projects of Agrotechnologie), in the expectation that the main process of acetic acid will occur in fermentation tanks (fermenters). Some developers do not isolate the acetic acid stage at all, feeding glucoamylases directly to fermenters.
The wort from the acetic acid is divided into two streams. Approximately 10… 15% of it is used for yeast generation, the rest is fed to fermenters. Wort intended for yeast generation is kept for about 20 minutes for deeper icing.
Cellulase and protease preparations are used in the acetic acid and/or fermentation step.
Cellulases are added to increase the yield of alcohol by using a readily available portion of the cellulose contained in the feed. Proteases make it possible to release amino acids for nitrogen nutrition of yeast, accelerate fermentation and reduce foaming due to hydrolysis of proteins.
The calcium-magnesium salt of phytic acid, called phytin, is a component of the intercellular structures of plants. Due to the formation of a complex with starch, phytin inhibits the activity of amylases. Because of this, almost 20% of the activity of α -amylase is lost during the preparation of wort.
Some cereals have endogenous phytase – an enzyme that, in the process of liquefaction and acidification, releases phosphates along with macro- and microelements (calcium, zinc, iron, selenium, etc.) when processing corn, sorghum or barley, it is very advisable to use phytase preparations together with amylases.
Phosphates released from a natural source are absorbed by yeast, stimulate their development and fermentation process. Free myoinositis is a yeast growth factor. The input of phytase preparations into the wort leads to the following positive effects:
- increasing the activity of bacterial amylases due to the stabilizing effect of released calcium and eliminating inhibition by phytin;
- a rapid reduction of wort viscosity during liquefaction;
- increasing the fermentation activity of yeast during the release of phosphates, macro- and microelements, metabolically active myo-inositol.
LIQUEFACTION
The technological mode of the liquefaction and icing process is selected depending on the type and composition of raw materials, the properties of the enzyme preparations used. Each manufacturer of drugs recommends its own temperature regimes, pH value and time of enzymatic treatment. Therefore, when designing the scheme and selecting equipment for this technological section, they try to provide for the widest range of possibilities for changing the listed parameters, taking into account further improvement of the process.