Improvement and optimization of coal washing plant in Liliangzhuang Coal Mine, Shandong Province

Shandong Liliangzhuang Coal Mine was completed and put into operation in 1957. It is a simple coal washing plant with an annual output of 300,000 tons. Due to outdated equipment, the technology is lagging behind in coal washing. After many considerations of the plant, the NHAK300/980 coal preparation equipment for large-scale coal washing equipment under construction by Lukai Machinery Co., Ltd. was finally selected. On March 18, 2008, the company officially took the test drive. The main products are clean coal, medium coal and straw stone. The coal washing process of this product is; the raw coal jumping platform selects the washing-washing mud flotation process - the slime water concentrated pressure filtration and the process flow. In the initial trial production and debugging process, the problems existing in the system will be upgraded and upgraded. This paper focuses on the process system design, equipment selection and characteristics of the equipment, and systematically introduces the actual operation results.

Coal washing process system design

1.1 Jigging washing system

The raw coal is crushed and screened, and the raw coal of less than 80mm is transported to the buffer tank through the conveyor belt and evenly enters the jig. Finally, the jig directly selects the vermiculite and the medium coal, and the slime water is dewatered on the self-flowing clean coal dewatering screen.

1.2 Coarse slime separation system

The slime water is automatically dehydrated and separated during the process of the clean coal separation system. The coal between 13mm-80mm directly enters the fine coal transfer belt, and the 13-0.5mm coal slurry water is kept from the coal slurry collection bucket of the island. Separation is carried out in the flow device, the multi-frequency sieve is arranged in the cyclone group, the water system is separated by the high-frequency sieve, and the clean coal is subjected to flotation extraction.

1.3 After the fine coal slurry enters the flotation system, the flotation liquid flows into the fine coal sludge collection system, and then is pumped to the flotation concentrate pressure filter to form a filter cake, and finally flows to the concentration tank.

3 main models and features of the equipment

2.1 Jig

At present, domestically listed jigging equipment generally has the following shortcomings;

(1) Domestic jigs generally consume a large amount of air and consume a large amount of energy. (2) The stratification effect of coal bed is not ideal, and coal resources are generally contained in meteorites, resulting in huge waste of resources. (3) According to the actual case of Shandong Liliangzhuang Mining Company, the phenomenon of “cracking” of domestic jig equipment will occur more or less, resulting in incomplete use of equipment, which greatly reduces the production efficiency of mining companies. The NHAK300/980 coal preparation equipment designed and manufactured by Hebei Tangshan Lukai Technology Co., Ltd. solves the above problems.

2.1 High precision CNC air valve

(1) Using the latest patent-multi-function electronic numerical control damper, the overall working effect and reliability of the numerical control damper are further improved, and the stability and reliability of the equipment are effectively guaranteed. (2) With the newly designed wind direction results, the humanized components are further improved, the technical level is more stable, and the energy is further optimized, which is beautiful and practical. (4) The multi-chamber shared damper is adopted, and the number of dampers and the number of maintenance are greatly reduced compared with the previous ones. (5) The new high-pressure wind co-wind system can save 100,000 yuan in electricity every year.

2.1.2 Body structure

(1) U-shaped oscillating air chamber structure, the washing water pulsation is smoother and the layering precision is higher; the new air structure design is more uniform in energy diffusion and less energy consumption. (2) The composite body consisting of a single compartment reduces the overall body weight by 30%, greatly improving the portability of the equipment. (3) The water below the sieve is fed along the whole aspect of the body, and the stability of the bed is improved by using the stability of the bed.

2.2 fine coal advanced precision grading dewatering screen

The YSL9824 linear high-precision vibrating screen designed and manufactured by Tangshan Lukai Technology Co., Ltd. is manufactured by the latest technology of Germany. It adopts the principle of double-axis synchronous block eccentric oscillation. The structure is abnormally simple. The spring adopts high-density rubber spring, low noise and reliable quality. The operation is stable, the screening efficiency is high, the use time is more convenient, and the maintenance aspect is simple.

2.3 Clean coal dynamic centrifugal dewatering machine

The clean coal dynamic centrifugal dewatering machine adopts JHG0-400 centrifugal dewatering machine. The machine is improved, with good dehydration effect, reasonable maintenance, reasonable lubrication, reliable operation and low noise.

3 Process system optimization measures

3.1 Measures to reduce the moisture content of clean coal products

Tangshan Lukai Technology Co., Ltd. actively carries out its work and takes effective measures to continuously improve and continuously optimize the equipment process system. The following aspects are specific.

(1) Considering that the degree of mud of the coal in the Liliangzhuang Coal Mine Washing Plant in Shandong is relatively serious, the width of the screen of the dewatering screen is greatly increased, and the two rows of 0.5 mm are changed into a row of 0.75 mm and a row of 1 mm.

(2) In order to reduce the moisture of the peat on the linear dewatering screen, the 13mm grade square hole screen of the linear vibrating screen is changed into two sections of 13mm and 20mm, and the feed amount of the centrifugal dewatering screen is increased, so that the output of the equipment is more optimized.

(3) Reforming the motor and material management of the high-frequency screen of the equipment, making the equipment more reasonable, eliminating the phenomenon of high-frequency screen running water, greatly enhancing the dewatering effect and dehydration ability.

(4) The pressing time of the equipment concentrate filter press is doubled, so that the fine coal water produced by the concentrate filter press is reduced to 28%, and the output rate is greatly improved.

3.2 Optimization of flotation equipment dosing device

Tangshan Lukai Technology Co., Ltd., the large coal washing equipment manufactured by NHAK300/980 coal preparation equipment, the original dosing method completely uses manual experience physical inspection flow material, reliability and stability are poor, uncertain and random, very large, for production And cost maintenance is unpredictable. After the work identification optimization plan is determined, through a large number of experiments, the flotation agent dosage and the ratio of the drug ratio are finally determined, and the previous manual ingredient means is changed, thereby greatly improving the use efficiency of the device.

5 summary

The improved coal washing system of the Liliangzhuang Mining Company in Dezhou, Shandong Province is simple, practical, stable and reliable, easy to operate, and has good economic benefits, providing reliable economic benefits for the coal washing plant.