preface
A company has two RMS51/26 vertical milling lines in Belizehuse, Germany and an LM6.3 3+3 vertical milling production line in Leicher, Germany, with an annual production of 2.4 million tons of slag powder. Compared with the operating data of peers, the economic indicators of the company's Two Mills of Burleigh Hughes and Leches mills (unit time output and energy consumption per unit product, etc.) are ideal in the industry, and this article briefly introduces the use of the company's vertical mills.
01
Device management aspects
The operating state of the equipment directly affects whether the production line is running in the most economical state, and there are several understandings in the maintenance and overhaul of the vertical mill.
(1) In terms of daily maintenance, the implementation of equipment grading control system, the libra host as a class A equipment management, operation support workers, professional engineers and department managers three levels of coverage patrol inspection, the implementation of the team inspection work and handover confirmation system, anjianhuan office to follow up the implementation of relevant safety measures. Emphasize the active maintenance mode and reduce the passive or faulty maintenance mode. Fixed repair adopts a process-oriented and standardized approach. That is, the maintenance plan and safety measures plan, the accident emergency plan are prepared and approved, the shutdown is locked item by item, and the start-up is delisted and confirmed item by item. Emergency repair or temporary minor fault handling is carried out according to the method of opening, stopping process and confirming each item, and confirming safety and security measures. Advocate preventive maintenance, combined with the inspection point verification and repair mode, in the early stage of failure completely eliminated, the production line equipment failure rate decreased year by year, has been at a low level (≤ 2.5%, equipment failure time / total running time + fault processing time, see Table 1), good equipment operation rate to avoid frequent fault start and stop, product quality assurance and single consumption indicators play a role in promoting.
Table 1 Equipment failure rate (%)
(2) Overhaul, the vertical mill output surfacing cycle is generally 30 ~ 400,000 t, at this time the mill grinding roller and the grinding area of the grinding plate irregular wear, coupled with the wear and tearing so that the gap between the grinding roller and the grinding disc increases, the equipment operation efficiency decreases, the energy consumption continues to increase, and eventually leads to the suspension of production and overhaul, in the overhaul of the grinding roller sleeve and the overlay welding of the grinding plate liner as the core work, the surfacing quality directly affects the operation of the mill within a cycle, so it is particularly important to do a good job of surfacing quality control. There are three aspects of surfacing quality, one is to clean the surface foreign objects, do coloring flaw detection, hammer one by one, to prevent empty layers and cracks, find problems in time to deal with, prevent problems before they occur; the second is the overall size, strictly control the shape of the grinding roller grinding disc welding completed, the arc shape must be guaranteed, the weld deviation is controlled within 2mm, do a good job of recording and taking pictures; the third is the degree of weld seam firmness, in the welding process, each welding 2 to 3 layers, by a special person through the hammer to check whether the surfacing layer is loose or void, such as timely processing, such as timely processing, Ensure that the entire operating cycle does not cause the overlay layer to fall off. Check the wear of the guide pin and the guide pin liner after each surfacing, repair and replace it in time, and adjust the guide pin pad plate to make the grinding area of the grinding roller grinding plate in the best position according to the size after repair or replacement.
Each operating cycle of Burleigh Hughes mill is 6 months (300,000 to 400,000 tons of output), check the wear of the roller and grinding disc every two months and combine the work of the main motor and the amount of external circulation, adjust the height of the retaining ring in real time, and ensure that the mill runs in a stable state.
02
Process operations
In the daily process operation, the relevant personnel instilled the production concept of high yield and low consumption, requiring the operator and the central control operator to be good at observing and studying the operation status of the mill, and making a summary summary, groping out the most reasonable control parameters, in the long-term operation, summarizing the following points:
(1) Pay attention to the use and collocation of raw materials, according to conventional practice, slag stacking and aging for more than a week and then use, good grindability, high feeding volume, low single consumption, but in fact, because the actual supply of steel mills can not meet the above requirements, so the joint storage is divided into four areas, every day strictly designated slag stacking area and use area, in order to reduce the raw material into the grinding water as much as possible, thereby reducing the single consumption.
(2) Strengthen the control of water into the mill, after a long period of observation, it was found that the Berley Hughes mill has higher requirements for the dry and wet production of raw materials, when the raw materials are too wet (more than 10% of the water), the mill has a poor work effect, the powdering efficiency is low, and it is easy to cause a large amount of external circulation; and when the raw materials are too dry (less than 8% of the water), it is not easy to form a stable material layer, the mill is easy to vibrate, which is not conducive to stable operation; and the Leche mill has not so high requirements for the moisture requirements of raw materials, and the dregs dry or wet a little affect it is not very large; after continuous attempts, When the grinding moisture is controlled at 8.5% to 9%, it can not only meet the moisture requirements of the two mills, but also make the mill run relatively stable.
(3) Do a good job of mill temperature control, after groping found that the outlet temperature of The Berleheus mill is above 105 ° C, the mill runs relatively smoothly, and the vibration value is small (below 0.6mm), while the main motor is low in work and the electricity unit consumption is low; the outlet temperature of the Lecher mill is controlled at about 110 ° C, the mill runs more smoothly, the main motor does less work, and the electricity unit consumption is lower.
(4) Pay attention to the mill work conditions, the actual production process is not the higher the feeding, the lower the power consumption, the production should always pay attention to the work of the mill, after long-term comparison found: When the Burleigh Hughes mill is running, the main motor current is controlled at 150 ~ 160A, the main motor has the best work effect; and when the Leicher mill is running, the main motor current is controlled at 350 ~ 360A, the main motor has the best work effect; when the main motor current exceeds the above range range, the main motor is not doing well, and the feeding is low when the table is fed The power consumption is high, so if you want the mill to operate efficiently and at low consumption, you need to monitor the main motor current at all times in order to adjust the production raw materials, feeding and retaining rings in time.
(5) Strengthen the fine operation, for abnormal situations in operation to do timely detection and early treatment, to avoid downtime, such as when the main motor current appears frequent small fluctuations, at the same time the hydraulic pressure also appears small fluctuations, it means that the mill is running unstable at this time, need to adjust the parameters in time to stabilize the material layer; and as before we lock the damper valve and into the grinding chute production for a week need to stop cleaning, and later by increasing the temperature, the chute is cleaned once a month, etc., the equipment operation rate is shown in Table 2.
Table 2 Equipment operation rate (%)
03
Consumption reduction measures
(1) Pay close attention to the use and collocation of production raw materials and moisture control, which is the key to reducing consumption;
(2) Before feeding and production, shorten the no-load running time of the auxiliary machine as much as possible to reduce the electrical loss;
(3) When starting the machine, under the premise of ensuring the smooth operation of the equipment, the feeding and other control parameters will be adjusted in place as soon as possible, so as to reduce the power loss at the time of start-up;
(4) Strengthen process operation and equipment maintenance, and maintain a high operating rate of equipment as much as possible;
(5) As far as possible to reduce the powder in the mill, so that the mill relatively maintain a low-consumption working state, such as when the quality of the table is better, you can put a wave of powder every once in a while (but it is not recommended to do so);
(6) Real-time control of the operation of production site equipment, timely stop unnecessary equipment, reduce energy waste;
(7) Pay close attention to the activity and intensity indicators of the product, so as to make timely adjustments to the product quality control indicators, so as to achieve production and consumption reduction.
04
epilogue
In the production process, we pay attention to sharing, good at summarizing, for good work experience can be shared in a timely manner, and strive to achieve one person to know the team, comprehensive promotion and comprehensive improvement; and for some deficiencies and mistakes in the work, we can also do timely analysis and summary, comprehensive education, to avoid making the same mistakes again; it is the summary, analysis, and promotion again and again, so that the entire team can be trained and promoted, so that the production organization is more orderly.
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