SUGAR PRODUCTION
MAIN RAW MATERIAL OF SUGAR:
Sugar (saccharose) is available in the body of most plants. However, there are two plants, which contain sugar as much as to enable the economic acquisition of sugar: Sugar cane and sugar beet.
Sugar cane, whose homeland is India and Arabian countries, is grown in tropical and semi-tropical zones of the world. In our country, sugar cane farming is not performed.
In the body of sugar cane, a sugar around 12-16% is available and three-quarter of the sugar produced in the world is obtained from sugar cane.
Sugar beet is grown in the zone having temperate climate, which covers our country as well. In the structure of sugar beet, there are 4-5% cellular tissue, 4-5% water with chemical bond and 90-95% sap. The compound of beet sap is as follows: 15-18% sugar (saccharose), 1,0-1,5% other organic matters except sugar, 0,8% inorganic salts.
PRODUCTION PROCESS OF SUGAR:
Production process of sugar from sugar beet consists of three main stages:
a) Beet preparation for processing,
b) Juice production and treatments,
c) Sugar House,
Area works and preparation of beet for plant:
After sugar beet cultivation is done, it is harvested in certain months of the year. Harvesting is generally done between September-November and the harvested beets are carried to the plant for the purpose of being processed. The beets arriving at the plant are directly received in the plant or in the silos at the site where they will be stocked for some time as to be processed later.
The beets directed to the daily plant are first taken to concrete silos in the front plant area and delivered to washing facility by means of water. In this facility, while the beets move from the channels together with water, stone catchers clean the beet from the stone and sand coming together with the beet because of the weight difference, grass catchers from the grass by holding them. Afterward, the beets arrive at the washing part and here they are cleared of the soil by being washed with water. The beets, which pass from a rinsing facility finally, are received into the daily bunker by being carried with belts.
Juice Production and Treatments
Juice Production and Treatment Processing:
At the juice production and treatment, the process consists of the following stages:
a) Slicing of the beet,
b) Diffusion process,
c) Refining of juice,
d) Filtration,
e) Thickening of clear juice (Evaporators)
Slicing of the beet:
Beet knives are shaped like a rotating drum on the boxes around of which knives having a special structure with a shape of plane are placed. Rotating movement transforms the beet, feeding from the inner part of the drum, into slices shaped like a prism. After the weighing of gravity on a belt scale, these slices are sent to scalding trough prior to the diffusion process.
Diffusion process:
The device through which the sugar in beet is taken from slices to the juice is called Diffuser.
The beet sliced in knives first arrives at a scalding trough and at the diffuser from here. In this system, the sugar within the beet cells penetrates into the hot water in the environment. The temperature is about 70 ºC. The situation here is similar to pouring hot water onto the dry tea put in the tea pot. As is known, the water will acquire the color of tea in a short time, namely, the abstract of tea will migrate to the water. Similarly, nearly the complete sugar in the beet migrates to the water within the diffuser. This process takes place in accordance with the principal of backflow. Namely, while slices enter into the diffuser from the bottom, hot water is applied from the top, exact opposite direction. The pulp leaving here is compressed in the presses before moving away from the system and its water is retaken as much as possible. So water and sugar loss moving within the pulp is reduced. The pressed water acquired is turned to the system again. This application is necessary in terms of energy acquisition as well.
The juice received from the diffuser is sent to the refinement station in order to be refined from the organic and inorganic matters within it except sugar.
Compressed beet pulp is sold in the form of open bulk as animal feed as well as it is possible to manufacture in the form of 1000 kg of packages or to manufacture tons of pulp, which is called sausage, in the form of single closed package at the consumption point.
Raw Juice Purification:
Refining process actualizes in the following stages:
a) Liming
b) Carbonations and filtration
Liming
The matters except sugar within the raw juice, which come from the beet, are precipitated, decomposing by lime milk. (Lime milk: Hydrated lime with water obtained through the hydrating of unhydrated lime by sugared water or water). The reason why lime is preferred as the refining matter is that it is a cheap raw material, easily available everywhere, it doesn’t give any harm to the equipments, its use is easy, it can be separated from the juice by filtration, a matter which is not harmful to the environment… etc.
Liming is applied in four steps. Three of these steps are performed by the addition of lime milk.
The first three liming are before 1st carbonation, the last liming is before 2ndcarbonation.
1stliming process is applied gradually. Ph in every stage is a little bit higher. The temperature is 50-55 ºC.
Main cold liming is performed in the same temperature range with 1stliming but in higher alkalinity than it.
Main hot liming is performed in the same alkalinity with main cold liming. The temperature of juice has been approximately enhanced to 85 ºC.
Carbonations and filtration :
The juice, whose liming process has been completed, comes to 1st carbonation. Calcium hydroxide, that is Ca(OH)2 permeates to solid phase in the form of CaCO3, precipitating, with the effect of CO2 applied to the environment. Meanwhile, the other suspended matters in the environment are included in the precipitate formed.
After carbonation, the juice is first filtered from the condensation filters, being transferred to filtration station. Juice with dense sludgy emerged is again filtered from the press filters and all of the juice is retaken.
Filtered juice is subjected to last liming, being allowed to turn to refinement station. After the last liming, 2nd carbonation process is applied and the lime applied in the last liming and remaining in the environment before completely permeates to solid state in the form of CaCO3.
Juice, which is sent to the filtration section second time is filtered and a clear thin juice is obtained.
Evaporation of Refined Juice:
Evaporation of thin juice is performed in the evaporation station (evaporators):
Evaporation Station:
The temperature of filtered thin juice is raised to 120 - 125 oC, being transferred through the heaters. And it is sent to stepped evaporation station.
Evaporation station consists of 4 or 5 stage with 2 evaporation devices in each stage or sometimes with 3 evaporation devices according to the vapour requirement in the third stages. Evaporation devices are cylindrical, with dished bottom and top, with heating chambers where vertical pipes are present in a point close to the bottom part. Vapour is used to heat the juice. Vapour and juice don’t intermingle.
The procedure is as follows:
Heated juice is transferred to 1st Stage Evaporator. The vapour at a pressure of 2,5 bars, temperature of 135 ºC coming from the steam boiler feeds the vapour chamber of this evaporator. Juice permeates to the next stage of a lower pressure by its own flow, condensing a little here. This stage is fed by the juice vapour of the first stage as the heating vapour. The procedure continues in this way and the density of the juice reaches 65 – 70 % DM (dry matter) in the last stage. So, the evaporation process has been performed in the evaporators.
The operating principle of the evaporators is consistent and the juice is consistently in flow in these devices. While the juice condenses in the evaporators, its colour can darken a little. While thin juice has the colour of olive oil, thick juice has the colour of weak tea.
SUGAR HOUSE:
Thick juice is transferred to refinery unit for the crystallization stages. Crystallization stages (boilers) are performed in three stages:
- A boiling
- B boiling
- C boiling
In the sugar plants, processing stages can differ from each other in details. In our Konya
and Çumra Şeker Fabrikaları (Çumra Sugar Factories), batch boiling system is applied in crystal sugar, and consistent cooking boiling system in the section of middle and C sugar.
A Boiling:
Boiling process of crystal sugar in sugar house is the process through which the standard syrup prepared following the combining of thick juice with crystal white syrup, middle B sugar and affinated sugar is thickened until its dry matter ingredient becomes 92 – 93 %. During this process, the sugar within the syrup crystallizes.
Boiling is performed in vacuum pans. In the boilers of crystal sugar performed in batches, each vacuum apparatus runs separately. Firstly the seed massecuite is braised in an apparatus allocated as seed vacuum. This seed massecuite is used in the seeding of the other vacuum apparatus.
Standard syrup, received into the vacuum apparatus, is evaporated and its water is removed. Seeding is performed at the saturation point, namely sugar crystals are applied to the environment and the boiling continues with these crystals. When the boiling terminates, C sugar massecuite is obtained. Boiling processes in vacuum apparatus are performed under negative pressure, in other words, under vacuum.
C sugar massecuite obtained is processed in centrifuges of the crystal sugar running in batches, in other words, the sugar crystals leave the covered syrup and wet crystal sugar is obtained. This sugar is transferred to drying - cooling unit.
The sugar dried and cooled, is transferred to sugar bunker in order to be packaged. In the full automatic packaging machines running without human touch, this sugar is bagged into the polypropylene sugar bags and their openings are fastened and delivered to sugar storehouse as sugar for sales. So, white crystal sugar has been obtained.
This sugar produced, is introduced to the market in the packages of 25 kg PP. (polypropylene), 50 kg PP, 1000 kg (big bag) or in the form of bulk sugar in closed tanker. Furthermore, in our Çumra Şeker Fabrikası, the varieties of liquid sugar, cube sugar, yummiest candy sugar, candy sugar are the products which we produce as sugar.
B Boiling:
The syrup separated in the centrifuges of crystal sugar is again received to boiling process in B sugar unit. B sugar boiling is performed in accordance with the principle of continuous boiling. In continuous boiling, the vacuum apparatus are designed either in the form of layer vacuums placed over and over (VL) or separate vacuums running in series collaterally (cascade). The operation principle in each one is the same and the series are continuous.
In continuous boiling, while the first vacuum pan is continuously fed by the seed, a consistent intake of massecuite is done from C vacuum pan. Since the system runs in automation, syrup feeding is applied to each vacuum pan as much as required.
Continuous boiling has some advantages compared to batch boiling. Therefore, this system is preferred in developing sugar technology. Boiling of B sugar, which ran in batches at Konya
Şeker
Fabrikası before, has been transformed into continuous boiling system in the revision in 2006. The system runs efficiently.
B massecuite received from the final vacuum of B sugar is transferred to the continuous centrifuges of B sugar in order to be processed. Here, sugar crystals and environment syrup are separated from each other again. B sugar returns to the system by getting into the mixture of standard syrup of crystal sugar. B syrup is transferred to C sugar unit for anew boiling.
C Boiling:
B syrup, emerging in centrifuges of B sugar is received into the boiling of C sugar. The vacuums of C sugar boiling completely run in the same form as the boiling system of B sugar in principle. In other words, it runs according to serial and consistent system. 1 piece of B sugar vacuum is allocated for seed boiling.
The massecuite obtained from the boiling of C sugar is transferred to crystallizers and the C crystallization is achieved. The massecuite received from the crystallizers is processed in the consistent centrifuges of C sugar. C sugar and syrup are separated in centrifuges. This syrup is molasses and transferred to molasses tanks as by-product. The massecuite is prepared through C sugar’s being subjected to refinement process, namely, being combined with some syrup and processed in the consistent centrifuges of affinated sugar.
The sugar leaving the centrifuges of affinated sugar has returned to the system through being used in the standard syrup of crystal sugar as such in B sugar. Affinated syrup is used as the boiling syrup of C sugar.
In our plant, some of the affinated sugar is used as the seed for B sugar.
Molasses:
As it is mentioned above, the C syrup emerging from the centrifuges of C sugar in sugar production processes is the molasses. The dry matter of molasses (Bx) is between 80 and 85 and includes sugar of approximately 45-50 %. Moreover, it is a combination rich in organic and inorganic matters. It also includes various amounts of different vitamins in its combination. Because of these properties, it is in the position of main raw material of some industrial branches.
Molasses is mainly used in the fields such as seed production, feed industry, alcohol production, etc in our country.
Energy Units:
Sugar plants are different from other industrial branches in some respects. One of these differences is the use of energy. The processed of sugar production stages such as heating, evaporating are done by vapour. This vapour is generated in vapour steam boilers. Some of the energy of pressure vapour is transformed into electric energy through being transferred from turbines before it is delivered to the plant, in other words, power generation is achieved. This electric energy generated has a quantity sufficient for the requirement of whole plant. At times the plant operates in normal capacity, electric energy from outside is not purchased in campaign.
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