Sugar production is the prerogative of large factories. After all, the technology is quite complicated. Raw materials are processed on continuous production lines. As a rule, sugar factories are located in close proximity to sugar beet cultivation sites.
Product Description
Sugar is essentially pure carbohydrate (sucrose), it tastes sweet and pleasant. It is well absorbed and ensures the normal functioning of the body (visual acuity and hearing, an important nutrient for brain cells, takes part in the formation of fats). Abuse of the product leads to the development of diseases (caries, overweight, etc.).
Raw materials for production
Traditionally, in our country, this product is made from sugar beets. Sugar production requires a large supply of raw materials.
Beetroot is a representative of the haze family. Grows for two years, the culture is resistant to drought. During the first year, the root grows, and then during the second year the stem develops, flowers and seeds appear. The mass of the root crop is 200-500 g. The mass fraction of hard tissue is 75%. The rest is sugar and other organic compounds.
Harvesting beets takes place over 50 days. At the same time, plants operate on average 150 days a year. In order to provide raw materials for sugar enterprises, beets are stored in so-called kagats (large heaps).
Sugar beet storage technology
Beets are laid in layers in the kagat in pre-prepared areas. If the storage technology is violated, the beets will sprout and rot. After all, root crops are living organisms. The characteristic of germination is the index of the ratio of sprouts to the mass of the entire fetus. In conditions of elevated temperature and high humidity, beets begin to germinate already on the fifth day of storage. At the same time, beets, which are located in the upper part of the kagat, germinate most intensively. This is an extremely negative phenomenon, which leads to a decrease in the efficiency of sugar production. To minimize losses from germination, when harvesting, the tops of the fruits are cut off, and the crop itself in the blades is treated with a special solution.
It is important to store the fruits in the kagati carefully, being careful not to damage them. After all, damaged areas of the fetus are a weak spot that affects primarily, and then healthy tissue.
The development of bacteria is significantly affected by temperature and humidity. If you maintain the recommended composition of the air and a temperature of 1-2 ° C, then the processes of decay are slowed down (sometimes they do not develop).
Beets, which are stored, are extremely contaminated (earth, grass). Dirt worsens the air circulation in the kagat, provokes decay processes.
Therefore, it is recommended to wash the beets and store them washed. In recent years, special devices are widely used that blow out weeds, straw and dirt.
Beet yield
One of the most important tasks is to increase the yield of sugar beets. It depends on many factors. Sugar production directly depends on the volume of collection, as well as on the technological quality of raw materials.
First of all, the technological qualities of cultivated beets depend on the seeds used. Modern technology allows you to control biological and other characteristics. Seed quality control can significantly increase yield per hectare of sown area.
Also important is the method of cultivating beets. A significant increase in yield is observed with the so-called ridge cultivation method (yield growth is from 15 to 45%, depending on the climatic characteristics of the region). The essence of the method is as follows. In autumn, special machines fill the ridges, so that the earth actively absorbs and accumulates moisture. Therefore, in the spring the land ripens quickly enough, creating favorable conditions for sowing, growth and development of fruits. In addition, beets are much easier to harvest: the density of the soil of the ridges is relatively low.
It is curious that this technology was proposed by the Soviet scientist Glukhovsky in the distant 20s of the last century. And relatively recently, the method was introduced in advanced countries.
Despite the great effectiveness, this technology has not found wide application. The reason for this is the lack and high cost of special equipment. Therefore, the production of sugar from beets has prospects for developing and reaching a new technological level.
Harvesting beets should be carried out before the onset of frost. Deliveries to the enterprises of digged beets can be carried out on a production basis or in a production and handling method. In order to reduce the loss of sucrose during prolonged storage at transhipment bases, the fruits are covered with straw.
Manufacturing process
The average sugar factory in Russia is capable of processing several thousand tons of raw materials (sugar beets). Impressive, right?
The basis of production is complex chemical processes and reactions. The bottom line is as follows. To obtain sugar crystals, sucrose must be isolated (extruded) from raw materials. Then sugar is separated from unnecessary substances and a product is ready for use (white crystals).
Sugar production technology consists of the following operations:
- cleaning from dirt (washing);
- obtaining chips (chopping, chopping);
- sucrose recovery;
- juice filtration;
- thickening (evaporation of moisture);
- boiling mass (syrup);
- separation of molasses from sugar;
- drying sugar.
Sugar beet washing
When raw materials arrive at the sugar factory, it enters a kind of bunker. It can be located both underground and outside. With a powerful directed stream of water, sugar beets are washed out of the hopper. Root crops fall on the conveyor, during the movement of which preliminary cleaning of raw materials from all kinds of debris (straw, grass, etc.) takes place.
Root crop chopping
The production of sugar from beets is impossible without chopping it. So-called beet slicers come into play. The output is thin strips of sugar beet. In the technology of sugar production, the method of cutting pieces is very important: the larger the surface area, the more efficiently sucrose is separated.
Sucrose Recovery
Through the conveyor, beet shavings are fed into diffusion apparatuses with a screw. Sugar is separated from the chips with warm water. The chips are fed through the screw, and warm water flows towards it, which extracts sugar. In addition to sugar itself, water also carries with it other soluble substances. The process is quite effective: the pulp output (the so-called beet shavings) contains only 0.2-0.24% sugar by mass fraction. Water, saturated with sugars and other organic substances, becomes cloudy and foams heavily. This liquid is also called diffusion juice. The most complete processing is possible only when the raw materials are heated to 60 degrees. At this temperature, proteins curl up and do not stand out from beets. Sugar production does not end there.
Diffusion juice purification
The smallest suspended particles of beet and dissolved organic matter must be removed from the liquid. Technologically, up to 40% of by-products can be removed. All that remains is accumulated in molasses and removed only at the final stage of production.
The juice is heated to 90 ° C. It is then processed with lime. As a result, proteins and other substances that are in the juice precipitate. This operation is performed on special equipment within 8-10 minutes.
Now you need to eliminate the lime. This process is called saturation. Its essence is as follows: the juice is saturated with carbon dioxide, which enters into a chemical reaction with lime, forming calcium carbonate, which precipitates, while absorbing various pollutants. The transparency of the juice increases, it becomes brighter.
The juice is filtered, heated to a temperature of 100 ° C and subjected to saturation again. At this stage, a deeper purification from impurities is carried out, after which the juice is again sent for filtration.
Juice must be discolored and liquefied (made not so viscous). To this end, sulfur dioxide is passed through it. Sulfuric acid is formed in the juice - a very strong reducing agent. The reaction with water leads to the formation of a certain amount of sulfuric acid with the release of hydrogen, which, in turn, brightens the juice.
After a rough and clean saturation, the output is 91-93% of the initial volume of high-quality, bleached juice. The percentage of sucrose in the resulting juice volume is 13-14%.
Moisture evaporation
It is made in two stages using special equipment. For the production of sugar in the first stage, it is important to obtain a thick syrup with a solids content of 65-70%. The resulting syrup undergoes additional purification and is again subjected to the evaporation procedure, this time in special vacuum apparatuses. It is necessary to obtain a viscous thick substance with a sucrose content of 92-93%.
If you continue to evaporate the water, then the solution becomes oversaturated, crystallization centers arise and sugar crystals grow. The resulting mass is called massecuite.
The boiling point of the resulting mass is 120 ° C under normal conditions. But further boiling is carried out in a vacuum (to prevent caramelization). In conditions close to vacuum, the boiling point is much lower - 80 ° C. This mass at the stage of evaporation in a vacuum apparatus is “alloyed” with powdered sugar. What stimulates the growth of crystals.
Separation of sugar from molasses
Sugar mass is fed to a centrifuge. There, crystals are separated from molasses. The liquid that is obtained after separation of the sugar crystals is green molasses.
Sugar crystals are trapped on the grid of the centrifuge drum , which are treated with hot water and steamed to bleach. In this case, the so-called white molasses is formed. This is a solution of sugar and the remains of green molasses in water. White molasses is recycled in vacuum apparatuses (to minimize losses, increase production efficiency).
Green molasses enters the boil in another machine. The result is the so-called second massecuite, from which yellow sugar is already being obtained. It dissolves in juice after the first purification.
Sugar drying
The sugar production cycle is not yet complete. The contents of the centrifuge are recovered and sent to dry. After the centrifuge, the sugar humidity is approximately 0.5% and the temperature is 70 ° C. In a drum-type dryer, the product is dried to a moisture content of 0.1% (this is largely ensured by the residual temperature after centrifuges).
Waste
The main waste products of sugar production from sugar beets are pulp (the so-called root-crop shavings), fodder molasses, and filter press dirt.
Pulp is up to 90% by weight of raw materials. Serves as a good feed for livestock. It is unprofitable to transport bagasse over long distances (it is very heavy due to high humidity). Therefore, it is purchased and used by farms located near sugar factories. To prevent damage to the pulp, it is processed into silage.
In some sugar beets, sugar beets are pressed (this eliminates up to 50% moisture) and then dried in special chambers. As a result of this treatment, the mass of pulp, ready for use for its intended purpose and transportation over long distances, is not more than 10% of its original mass.
Molasses - feed syrup - is obtained after processing the second massecuite. Its volume is 3-5% by weight of the feedstock. 50% of it consists of sugar. Molasses is an important component in the production of ethyl alcohol, as well as in the production of animal feed. In addition, it is used in yeast production, in the manufacture of citric acid and even medicines.
The volume of filter press dirt reaches 5-6% of the mass of unprocessed raw materials. Used as fertilizer for agricultural soil.
Refinery Production
The production of refined sugar is usually located in the sugar factories themselves. These plants have special workshops. But third-party organizations that purchase granulated sugar at factories can also produce refined sugar. According to the production method, the refined sugar can be cast and pressed.
The sequence of technological operations in the production of refined products is as follows.
Sugar is dissolved in water. Thick syrup is processed to remove various coloring substances. After cleaning, the syrup is cooked in a vacuum chamber, and the first refined massecuite is obtained. In order to eliminate yellowness, ultramarine is added to the vacuum chamber (0.0008% of the mass of syrup, not more). The boiling process itself is similar to the boiling process in the production of sugar.
Refueling massecuite needs to be whitened. A dense mass is formed (pulp with a moisture content of 3%, no more), which is pressed. The result is a refined product that takes the form of a press. In order to obtain refined sugar in the form of heads, the massecuite is poured into the corresponding forms. At the bottom of the mold there is a special hole through which the remainder of the solution flows. Wet refined is dried with hot air until the moisture index decreases to a value of 0.3-0.4%. Then it remains only to wait until the sugar cubes have cooled, cut (if necessary) and pack.