Raw sugar processing

Practical solutions

Due to the specific properties of raw sugar, this raw material requires special technological equipment and a technological process that ensures the primary processing of raw materials and the preparation of a sugar-containing solution. As with the processing of other additional raw materials, the processing of raw sugar includes the main technological equipment and additional equipment. When processing raw sugar, the production stage of acceptance and primary processing of the main raw materials (sugar beet) is excluded from the technological process, which means that when processing raw sugar, all equipment located before the installation of the SUSEP membrane filtration, as well as equipment for processing beet pulp, will be turned off. The buffer tank used between the diffusion unit and the membrane filtration unit is also excluded from all equipment. The main components of RAWSEP process equipment are special equipment: crushers, a dispenser of crushed raw sugar, a water dispenser and a mixer for the solution, as well as a solution heater. This equipment is responsible for the quality of the resulting sugar-containing solution and its supply to the filter unit. The mixer-dispenser is equipped with a sugar meter, as well as other measuring devices responsible for monitoring the remaining foreign components in the solution. With the help of a number of measuring instruments and a special algorithm, the composition of the prepared sugar-containing solution is analyzed. The PLC has a program that is responsible for the operation of proportional valves, which, depending on the composition of the solution, increase or decrease the water supply. WESTTEX has developed a unique software algorithm for processing raw sugar, which guarantees the necessary and constant composition of a sugar-containing solution suitable for optimal sucrose extraction and removal of extraneous matter using membrane filtration.

In the warehouse, raw sugar that has entered the receiving pit, with the help of belt conveyors, enters the magnetic cleaning of possible metal objects, after which it enters the roller crusher. In a roller crusher, large pieces of sugar crystals of raw cane sugar are crushed to simplify and accelerate the sifting process through a drum sieve to remove non-metallic extraneous оbjects. The pieces of raw sugar that have entered the sieve are returned back to the crusher for crushing, extraneous objects are separated, and the fine fraction of raw materials is fed into the plate crusher by belt conveyors. In practice, we have proved that when processing raw sugar, double crushing is required. The reason for this decision is large pieces of sugar crystals, which may contain non-metallic solid objects (stones, plastic objects, etc.) that are not removed by magnetic separation, and that fall into the plate crusher can easily spoil it. In a plate crusher, raw sugar is crushed to a fraction of 0.01 - 0.15 mm. This process is very important, since only a small fraction according to the granulometry of sugar crystals is able to dissolve evenly and quickly in water, thereby reducing the steam consumption necessary to heat the solution and accelerate the precess of preparing a sugar-containing solution. The crushed sugar crystals are fed by a screw dispenser to the dissolution unit, where, with the help of supplied water and steam heating, a sugar-containing solution is prepared, the sucrose concentration in which reaches 23-25% at its temperature of 62-65 °C. In the future, the prepared solution in the mixer dispenser is diluted with water to a sucrose concentration of 20 ± 1%. The finished solution is fed into a buffer tank, which plays the role of compensation storage. The sugar-containing solution coming out of the buffer tank is heated to 70 °C, passes through a mechanical filter and enters the high-pressure pump of the SUSEP process unit.

The useful area of warehouses for processing raw sugar is selected depending on the installed capacity of the SUSEP and RAWSEP processing equipment, the planned annual duration of processing raw sugar and the frequency of replenishment of the reserve of raw materials. Storage rooms should be dry, since sugar is a hydrophobic substance.

Recommended packaging types depending on the capacity of the sugar factory:

by raw sugar (TRD)

(10-100 tons)

(200-600 tons)

(1000-2400 tons)

Basic parameters

RAWSEP technology is an additional equipment to the main equipment intended for processing the main raw materials, and is supplied separately. When processing raw sugar, the SUSEP and RAWSEP processing equipment works simultaneously, but only one type of raw material can be processed at the same time. The set of equipment for processing raw sugar depends on the general basic parameters of the sugar factory and the installed nominal capacity of the plant for processing the main raw materials. In accordance with the specifics of the processing of sugar beet and raw sugar, the ratio between the permissible nominal productivity during the processing of sugar beet and the possible daily volume of processed raw sugar is 5:1. In accordance with this, each set of RAWSEP process equipment includes warehouses of the necessary area for storing raw materials, guaranteeing continuous operation for 240 days. The storage equipment includes a receiving pit and a conveyor system. At the request of the client, we can design and supply warehouse equipment for small warehouses. The warehouse area is selected depending on the selected working cycle, the duration of processing of this raw material and the possibilities of periodic supply of raw materials.

The conveyor system is selected depending on the flow of raw materials supplied to the production and the location of the main equipment. The conveyors are made exclusively of flat surface belts, as this ensures a uniform flow. Feeders of belt conveyors are equipped with level sensors that measure the flow of the transported product and avoid overloading the conveyors and guarantee their smooth sequential start. Absolutely all electric conveyor drives are equipped with frequency converters (VFD). This solution allows parameterizing and optimizing the operation of all conveyors, avoiding possible overloads and significantly reducing energy costs.

Roller and plate crushers are made of high-quality steel, and the internal areas are covered with an antistatic and slippery coating. The electric drives are equipped with frequency converters (VFD), which allow changing the rotation speed and thus controlling the crushing process.

RAWSEP process equipment is equipped with two dispensers. One is designed for the dosed supply of crushed raw sugar into a container for dissolution, and the other is used to dilute the sugar-containing fluid with water, to reduce the concentration of sucrose to 20%. The first of them has two dosing levels, since two dosing screws are installed in it. The first screw is designed for rough dosing (0-95%) of the required flow (kg/s), and the second is designed for accurate dosing by adjusting the exact flow rate within 0-5% of the required flow of raw materials (kg/s). Both metering screws are controlled by proportional control (PID). The process is controlled by a PLC using signals from sensors of sugar content, turbidity, temperature, etc. The dispenser for diluting sugar-containing juice operates in PID mode using a PLC that receives the necessary variables from external signal sources. Data between all PLCs is transmitted via the Modbus RTU protocol.

The prepared sugar-containing solution cools down when stored in a buffer tank. To avoid this process and maintain an optimal temperature for fluid filtration is heated to 67-72 ° C using a flow heater before being fed to the high-pressure pump of the filtration unit. In the form of a heater, a shell-and-tube heat exchanger is used, consisting of a large number of parallel pipes and an external casing. The heat exchanger tubes are made of AISI 310 stainless steel, which is resistant to the high temperature of the steam surrounding them. In addition, stainless steel of this brand is more resistant to many chemicals and their compounds, which makes the device resistant to sanitary cleaning solutions.

Note:the table does not specify the number of conveyors and pumps, as well as their performance, since these data are determined only when choosing the required configuration of equipment, depending on general technical conditions and requirements for sugar plant.

Basic parameters:

Attention:this table does not indicate the power and electricity consumption of individual units and aggregates, since these characteristics mainly depend on the configuration.