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FACTORS AFFECTING EFFICIENCY IN GRINDING AND ENERGY MANAGEMENT IN THE MILLS

11 November 20196 min reading

The cost of energy consumption is one of the most important subjects causing headache for the flour factories that already operate with a low-profit margin. At this point, keeping the energy costs at the minimum level and rational use of resources in the factory without making any sacrifice on the quality of the final product play a critical role in company’s profitability. It is necessary to prevent the use of the equipment under the capacity. Within this scope, proper maintenance of the equipment and adjustment is essential. It is essential that new technologies, which will increase productivity and efficiency, help to reduce costs.

The efficient use of resources is critical for every sector. This rule is also vital for the milling industry, where fierce competition is experienced and profit margins are low. Therefore millers do their best to obtain high efficiency. Raw material, equipment and production flow are the key factors affecting the flour yield. Grain characteristics such as moisture content, environmental characteristics such as temperature and humidity in the mill and the level of experience of the miller are other factors affecting the yield. Besides that; proper handling, cleaning and preparation for milling are significant to prevent unnecessary losses of wheat.

Efficient utilization of resources is a critical aspect of the process for any industry. In the case of wheat flour milling it is of great importance as wheat costs make up over 80% of the cost of flour. Any additional gain in flour yields translates to added revenue. In a competitive environment any such gain is of importance especially considering the fact that in most markets the price differential between flour and millfeed is anywhere from 3 to 5 times or more. At the same time high level of efficiency must be maintained in ensuring that finished products are being delivered at the optimum acceptable moisture levels. Efficiencies must be maintained in preventing any losses of wheat into screenings and any solids through improper filter system.

OPERATIONAL FACTORS Rolling distance: The rolling distance is the main operating factor that determines the grinding effect. The rolling distance adjustment is the main operation content of the grinding machine. In actual production, the technical characteristics of the powder path and the grinding roller are generally relatively stable, and when the conditions of the raw material, moisture, climatic conditions, grinding teeth are changed, the grinding effect is mainly corrected by adjusting the rolling distance.

When the 1B rolling distance is 0.9mm, the peeling rate is 20%; when the rolling distance is 0.7mm, the peeling rate is increased to 35%; when the rolling distance is reduced to 0.5mm, the peeling rate is 75%. The rolling distance is in the range of 0.5-0.7mm, which has the greatest influence on the stripping rate.

Flow rate: The unit flow rate of the flour mill is usually expressed in units of contact length of the roller unit, ie kg/cm. When the flow rate is too large, the homogeneity of material crushing will be reduced. If the flow rate is too small, the feeding state is not normal and the equipment operation is unstable. The 1B mill will control the entire powder flow. In addition to the final equipment, the grinding effect of each milling machine and the screening effect of the corresponding screening equipment will affect the working status of subsequent equipment. When the flow rate is large, the rotation speed of the grinding roller can be appropriately increased. However, when the rotation speed is high, the loss and vibration of the equipment will increase.

The cost of energy consumption is also one of the most important subjects causing headache for the flour factories that already operate with a low-profit margin. Power requirements in mills is one of the highest of all operational costs, and it is pertinent that all equipment used, is run at optimum capacity to avoid underutilization and wastage. Energy management should be planned in more details, the measurements should be conducted more fastidiously, and energy consumption should be closely monitored.

The electrical engineering team has to regularly inspect and correct any anomalies in the transformer banks, capacitor banks and MCB’s, thereby ensuring that there are no unnecessary interruptions during normal operations. MCC’s have to be inspected regularly during which time the electricians must check and ensure that all connections to and from the circuit breakers and overloads are tightened to avoid shorts and failures during normal operations.

Most mills around the world are allocated power off the local power grid, that has to be consumed by the mill or a levy is imposed by the supplier. It is therefore extremely important for the miller to ensure that when the facilities are operational, that they operate at design capacity or better always, and that the parameters set out by management for target moisture content of conditioned wheat as well as quality parameters for milled products are met. This is only achievable if all plant and equipment are maintained and adjusted correctly.

Exploring new technologies may also help to improve efficiency, increase productivity and reduce costs. For example, many companies are now using cloud computing systems as opposed to in-house hardware that can be relatively expensive to buy and maintain.

                COVER STORY INDEX               

  • Mills are becoming autonomous Stefan Birrer, Head of Business Area Milling Solutions, Bühler The principle and processes of the “mill of the future” are not clearly distinct from those used in mills today. But they do take up less space, are more energy efficient and operate increasingly more autonomously. [button color="blue" size="small" link="https://millermagazine.com/english/mills-are-becoming-autonomous/.html" icon="" target="true"]Read More >>[/button]
  • Save your energy Prof. Gustavo Sosa, Industrial Mechanical Engineer, SOSA – Engineering Consultants Having to start and stop equipment manually means having longer times when you grain isn’t processed. You start the motors in an operation, from last to first, and you have to make sure the equipment is running in regime (in normal stable operation) before starting the next one. If you do it by instinct, you will naturally wait a little more than required, just because of the fear of getting a clog in the system and have your boss screaming at you. An automatic system can be calibrated to wait just the minimum, thus saving valuable time that would be otherwise wasted running machines empty. [button color="blue" size="small" link="https://millermagazine.com/english/save-your-energy/.html" icon="" target="true"]Read More >>[/button]
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