1 question raised
One of the main economic indicators of the grade powder production line, electricity consumption, is extremely important in today's highly competitive market. In particular, the introduction of complete sets of equipment grade powder production line, although the equipment is sophisticated, the process is reasonable, but its product quality, price and market are both unified and contradictory. Whether it is unity or contradiction, energy conservation is always the only way to reduce costs, and practice has proved to be effective. Although there are many influencing factors, the skeleton factor is still energy consumption. The energy consumption point of the grade powder production line is in the milling, and the energy consumption point of the milling is grinding, sieving and cleaning, and the most important one is the grinding-energy peak control point. Control this point, that is, grasp the bottleneck benefits. This article takes the introduction of the MDDK type mill of the grade powder production line of the Swiss Buhler company as an example, and discusses the practice of energy saving, aiming to improve together.
2 equipment prerequisites
The prerequisites for the device depend mainly on its technical status. The state of technology usually refers to the working capabilities of the device itself, including: performance, accuracy, efficiency, motion parameters, safety, environmental protection, energy consumption, etc., and their changes. Whether these parameters are matched, normal, and optimal is directly related to the smooth realization of indicators such as product quality, quantity, and cost. Among them, the energy consumption index is one of the main indicators for measuring the grade powder production line, and it is also one of the veto votes for the complete equipment. Therefore, the primary task of energy saving and consumption reduction is the integrity of the equipment and the state of the equipment.
2.1 The perfect standard of the mill
(1) The body is solid and firm, the components are complete, vibration-free, noise-free and smooth. (2) Each operating system is sensitive and reliable, and the effective processing of the rolling distance correction device is sufficient; the two supporting distances are suitable, in the middle position of the thread, and continuously adjustable, and the axes of the two rollers are parallel. (3) The feeding mechanism is flexible, the material is evenly distributed, and the servo characteristics are advanced, achieving “fast, stable and accurateâ€. (4) Buffer springs and safety protection devices, all kinds of instruments are complete, complete and reliable. (5) The cleaning device is complete and effective, the connection is firm and the movement is in place. (6) The air control system is normal, the opening and closing is stable, flexible and reliable, and the characteristic indicators are “fast, stable and accurateâ€. (7) The transmission system is flexible and reliable, the gear position is complete and effective, and there is no abnormal vibration and noise. Gears, belt drives, and support bearings are in good condition. (8) The lubrication system of each department is complete, the state and performance are good, and there is no obvious temperature rise fluctuation during operation. (9) Power consumption is normal, there is no “four leaks†phenomenon.
2.2 State control of the mill
The means of state control is the status check operation. The activity of detecting abnormalities occurring in the equipment and deterioration occurring over time and predicting the residual life of the equipment by the human sense or by using inspection instruments and equipment. Its purpose is to detect fault signs and performance hazards early, so that faults are eliminated in time to ensure that the equipment operates normally and safely.
3 Qualitative principles of operation and adjustment
The powder road is the innate foundation, and the Swiss Buhler Group's set of grade powder production lines is relatively complete. The operation and adjustment of the mill is the basis of the day after tomorrow, which determines the quality of the product and the energy saving.
General requirements: The specifications of the stripping rate and powder extraction rate of each grinding system meet the design requirements; If there are changes, fluctuations, appropriate adjustments, establish a new balance, achieve stable production, less investment, more output, and achieve the goals set by the design.
The milling process has strong continuity. In the night production process, as long as any uncoordinated and unbalanced phenomenon occurs in any part, it will affect the production, product quality and cost. Only good equipment and reasonable process flow, without flexible correct operation and adjustment methods to adapt to existing equipment and processes, can not achieve the comprehensive requirements of good quality, high powder rate, low power consumption and high output. The operation and adjustment of the powder mill is particularly important. The operation adjustment process of the mill is actually a process of recreating the design of the milling process; it is a process of compensation and improvement. Flexible and correct operation is an important guarantee for the stable production of the existing process, and the correct operation of the mill is the most important part of the stable production, energy saving and consumption reduction.
The grinding effect of the mill is based on the stripping rate and the powdering rate as the final evaluation negative index. The stripping rate of the anterior skin mill is related to the proportion distribution of the whole powder road material, and it is also the key to energy saving control.
The operation and adjustment of the mill is mainly the matching process of the flow parameters, the rolling distance, the stripping rate, the powder extraction rate and the power consumption.
The required indicators to be achieved by the mill: stripping rate and powdering rate are used as indicators for measurement and determination. The flow and the rolling distance are the main means to achieve operation and adjustment. One of the operational requirements of the flow is to ensure uniform material distribution on the grinding rolls. The first thing is the adjustment of the position of the feeding door, the feeding speed, the servo characteristic parameters, etc., so that the gap between the valve and the feeding roller is uniform in the whole length direction; the feeding speed is stable, and the falling point is accurate, thereby ensuring the entire grinding roller. The material distribution is uniform, and the servo mechanism characteristics are advanced, achieving “fast, stable and accurateâ€. At the same time, it should also try to make the feeding of the system always make the material in the grinding machine collection material between 1/3 and 1/2. Ensure that the flow outside the machine is stable, so that the mill is stably in the grinding state for a long time.
On the basis of comprehensive system mastery of the milling process route and flow balance table, attention should be paid to the operation and adjustment of B1 grinding. Its stripping rate and flour extraction rate play a decisive role in the balance of the entire powder path. Adjust the operating flow of the B1 mill to a slightly lower than normal flow rate and keep it constant, then adjust to the rolling distance. In the adjustment of the rolling distance, special attention should be paid to the peeling rate of the B1 mill and the change of the size of the flour extraction rate, generally not more than 25%. Because the B1 grinding and scraping rate and the powder extraction rate have a great influence on the flow distribution of the rear skin mill and the heart mill, it is related to the balance of the proportion distribution of the whole powder road material. If the stripping rate and the powdering rate of the B1 mill are both high, the over-tightening of the rolling distance, the excessively broken, the broken bran and the small amount of bran affect the flow rate of the B1 mill and other mills. If the arrangement of DD is adopted, it means that the rolling distance of B1 mill is too tight, the equipment is not safe, the B1 grinding itself is overburdened, and the bran is excessively broken, and a large amount of fine bran is produced for the quality of the flour and the unit power consumption. To adverse effects. If the stripping rate and the powder extraction rate of the B1 mill are too low, there is no doubt that the load of the back grinding and the heart grinding will be increased, thereby affecting the performance of the equipment.
When the flow rate changes, the rolling distance should also change accordingly, in order to maintain the balance between the original stripping rate and the powdering rate. For grinding other than B1 grinding, of course, as the flow rate changes, the rolling distance is changed to ensure the stability of the powder path. The flow rate and the adjustment of the rolling distance and the set value must be subject to the limits of the stripping rate and the flour extraction rate. When the rolling distance is constant, the flow rate increases, then the power consumption increases, and the stripping rate decreases. If the flow rate decreases, the output decreases, indicating that the B1 grinding distance is too tight, and the material flow does not flow down, which also reflects the screen. There may be problems with the network equipment, and the power consumption will change accordingly. If the flow rate is stable; when the rolling distance adjustment cannot solve the problem, the most important technical characteristics of the grinding roller and the sieve number and the screening area of ​​the powder sieve can be reconsidered.
In short, flow, rolling distance, stripping rate, flour yield, yield, quality, technical characteristics of the grinding roller, sieving area, screen equipment, wheat quality, moisture, abrasive material properties, mill performance, operation and adjustment, Indicators such as power consumption are related indicators that are mutually constrained. It is necessary to formulate plans and redistribute through comprehensive and integrated consideration of various channels. In actual operation, the theoretical set value and actual value of each grind should be close. Otherwise, it indicates that the flow and the control of the rolling distance are distorted and unbalanced, resulting in uneven power consumption and other indicators.
For the grade powder production line, the rolling distance of the anterior skin mill should be large to keep the bran piece completely and less of the skin grinding powder, so the flow rate should be increased. In the posterior skin grinding, although the milling method is different, the ground materials are basically the same, so there is a certain difference in the unit flow rate. Usually, the length of the skin grinding system is higher, because the length of the skin grinding system is long, the grinding degree required for each skin grinding can be suitably lower, the rolling distance is relaxed, and the unit flow rate is high.
Since the heart-grinding system uses a light roller and the flour has a relatively fine grain size, the flow rate of the heart-grinding system is relatively low. In operation, the skin grinding system must be controlled according to the specified stripping rate and powdering rate, limiting the powder yield of the anterior skin mill, extracting as many high-quality coarse-grained powder as possible, and sending it to the number of passes, equipment More heart grinding systems and powder cleaning systems. In the actual operation, the peeling rate of each skin mill should be measured, especially the B1 and B2 grinding, which should meet the set value requirements, and should not be arbitrarily changed and adjusted during the operation.
The operation of the heart-grinding system must allow the material to be ground and sieved to obtain the highest quality flour at the highest unit flow rate and lowest energy consumption. In order to ensure that the heart-grinding system is effectively ground and sifted, it is necessary to first feed the materials of similar size and ash into the same heart mill, and at the same time equalize the unit flow of each mill and the flat screen.
The rate of powder extraction in the heart-grinding system depends on the size of the heart-milling. The size of the rolling distance depends on the thickness of the material, and the granule grinding material of the anterior road is larger than the particle size of the rear road material, so the rolling distance of the anterior core grinding is larger.
The overall effect is: negative pressure inside the machine, no feeding material in the feeding roller, no dust overflow phenomenon in the opening door; no powder in the surface of the smoothing roller during operation, no powder ring; no tooth shreds, no pressing cake; Under the premise that the powder rate and stripping rate reach the index, the energy consumption is the smallest.
4 implementation of energy-saving regulations and requirements for the rate of start-up
4.1 Implementation of energy saving procedures
The energy-saving procedure is a technical specification for the operator to achieve correct operation, energy saving and consumption reduction. It is based on the requirements of material quality, nature, grinding requirements, flow rate, technical characteristics of the surface of the grinding roller, performance of the milling machine and operation and other factors. Basic rules for matters, procedures, and actions that equipment operators must follow during their entire operations. The energy saving procedures for the MDDK mill are as follows:
(1) When the proportion of hard wheat, thick wheat and poor quality wheat in wheat is imbalanced, it is necessary to make timely adjustments, such as no effect parking to do the corresponding treatment. (2) When the moisture is too high and the moisture regulation is poor, stop the treatment. (3) The rolling stroke is not adjustable, or too tight, the grinding teeth are too blunt, the drawing quality is poor, the sandblasting quality is poor, the grinding roller device cannot be leveled, and driving is not allowed; the lubrication is not allowed to drive. (4) The flat screen sieve type is wrong, the screen area is inefficient, and driving is not allowed. (5) Poor suction, should be adjusted, stop the dust when it overflows; when the cleaning device is invalid, it is not allowed to drive. (6) The motor power should match the actual demand. Otherwise, replacement adjustments should be made. (7) When the wind power network fails, it is not allowed to drive. (8) Always check whether the load of each grinding machine is balanced, whether the flow rate is balanced, whether the two ends of the grinding roller are leaking, and do the corresponding treatment. When it is invalid, stop processing. (9) Always check the powder content of the materials on each mill and the working condition of the suction system. The temperature of the material is normal. The grinding roller buffering device is effective and the feeding and grinding process is correct. Otherwise, driving is not allowed.
4.2 The pursuit of starting rate
The equipment start rate is a comprehensive indicator and a system indicator, which is more than just a single indicator on equipment management. It is a comprehensive reflection of factors such as process organization, process arrangement, process discipline implementation, process operation, production command, production deployment, equipment maintenance, equipment integrity, equipment maintenance and other factors. In principle, the procedure is coherent, the time is compact, the personnel are arranged in an orderly manner, and the equipment is efficient. In order to make the starting rate high, it is necessary to increase the safe operation rate and minimize the setting failure rate and the process failure rate. In the management of reality, it can be used as a model to evaluate.
5 evaluation
Energy-saving work is not only a management task, but also a combination of multiple technology management, and it is one of the determining conditions for unit cost economic benefits. If this work can be done well, it is possible to reduce the energy consumption to 61 degrees per ton (200T per day), and its multiple management work will result in a virtuous circle. Energy conservation and consumption reduction are of course pursued by enterprises, but more importantly, the unit cost-effectiveness is the best.