In view of the status quo of most cement companies in China and the deficiencies of the traditional drying wind sweeping technology, on the basis of summing up many years of technical renovation experience, Zhenjiang Xingliang Machinery Co., Ltd. developed a new type of raw material drying and powder. Grinding technology and equipment. The use of several cement companies in φ1.83m×7m, φ2.2m×6.5m and φ2.4m×8m raw material mills shows that the technology and equipment can be widely applied to the raw materials with large moisture content and low mill output. The raw material mill technology reformation has the following advantages: 1 Larger production rate; 2 Significant energy saving effect; 3 It can make full use of the existing separators and dust collectors to reduce one-time investment.
The traditional drying and grinding technology, simply put, the materials are dried in the grinding process at the same time, and the materials are crushed on one side and dried on the other side during the grinding process. As the material is highly dispersed and directly suspended in the hot gas stream, the heat exchange is rapid and the water evaporates quickly. At the same time, due to the higher wind speed inside the mill, fine powder and water vapor can be discharged in time, thus avoiding the sticking and grinding phenomenon, so the grinding efficiency is higher.
1. System process and main equipment According to the dust collection equipment used for raw material grinding, the closed-end raw material mill of high-voltage electrostatic precipitator is adopted for the grinding tail. The process flow is as follows: the high efficiency and environmentally friendly hot gas stove and the mixed fuel are added to the grinding head. The chamber supplies the heat needed to dry the raw material into the mill. The hot air enters the mill through a special grinding head feeding device and the material. The heat exchange occurs during the operation of the mill. The dust exhaust gas is discharged from the mill tail. The tube directly enters the dew condensation-type high-efficiency and low-resistance coarse powder separator to separate the gas and material. The separated dust gas enters the high-voltage electrostatic precipitator and is purified again. The purified gas is discharged into the atmosphere by the exhaust fan. The dust collected by the coarse dust separator has reached about 20% due to the 0.08mm square-hole sieve. Therefore, it enters the separator with the milled raw material to conduct powder selection, and is collected by the high-voltage electrostatic precipitator. The powder and the finished product selected by the separator are sent to the raw material warehouse via the conveying equipment. As the drying and grinding technology is adopted, the wind speed in the mill is increased, the flow velocity of the material in the mill will be accelerated, and the circulating load of the mill system will increase to about 300%.
1 grinding head drying oven. High efficiency and environmentally friendly hot gas stoves and mixed combustion chambers are used. The coal is first converted into gas in a hot gas furnace, and then sent into the combustion chamber through a pipeline. The secondary air is fully mixed and burned. Since there is always an open flame in the combustion chamber and the combustion air is sufficient, The gas can be quickly and completely burned, resulting in high heat generation and high thermal efficiency, low coal consumption, and low power consumption. At the same time, there will be no smoke generated after converting coal into gas, and environmental protection and sanitation will be achieved. In the absence of conditions, it is also possible to use an artificial coal-fired furnace. If it is operated properly, it can also be used for drying and grinding.
2 grinding structure. Therefore, the class mill belongs to the tail unloading lift wind sweeping mill. The section wind speed of 3 to 4 m/s directly extracts part of the fine particles out of the mill and enters the separator and dust collector for gas separation. Most of the material is discharged from the mill tail. Out, by the elevator into the powder machine. The raw material fineness requirements are mainly uniform particle size and do not pursue high specific surface area, so the fine particles and dried steam are directly extracted from the mill, eliminating or reducing the resulting bond, adsorption, material matting factors, and reducing the The phenomenon of grinding, so that the mill in the high cycle load to fully display its ability to achieve the purpose of increasing the output of the mill. The inner lining plate of the mill adopts a stepped lining plate and a small corrugated lining plate according to the requirements of the drying mill, and the gradation of the ball segment is appropriately adjusted to ensure the balance between the two silos of the mill. At the same time, it is necessary to make appropriate alterations or replacements to the original mill diaphragm plate and discharge plate to meet the requirements of the wind sweep mill. In addition, the process requires a maximum particle size of <10mm.
3 Dust removal system. Most small and medium-sized cement companies in China generally use high-pressure electrostatic precipitators and air-bag pulse bag dust collectors as raw materials for the purification of tail gas containing dust. The dust collector is required to operate stably under the limit of 5% to 6% of gas moisture content and maintain low resistance to reduce the power consumption of the system. At the same time, due to the drying and grinding technology requirements, the wind speed inside the mill is higher and the ventilation volume of the system is increased. Therefore, when using the existing dust collector, it is necessary to take into account the situation after the technical reform, otherwise the dust collection system is difficult to operate normally. Therefore, in order to make full use of the existing dust collector to reduce the one-time investment, high-efficiency, low-coarse-powder separators should be used to pretreat the grinding gas in order to ensure that the tail dust collection meets the drying wind sweeping grinding technology requirements.
2. Problems to be solved when using the new drying and grinding technology and equipment The new drying and grinding technology and equipment are particularly suitable for most of the shaft kiln cement companies in China, because most of the shaft kiln companies in China use small grinding machines (ie: φ1 The .8m, φ2.2m, and φ2.4m mills), after adopting this technology, can not only guarantee the production and quality of the shaft kiln production line, but also can use the cheap electricity and the grain price electricity to regulate the production and achieve energy saving. Reduce consumption, achieve good economic and social benefits. At the same time, it can also meet the needs of large-diameter shaft kiln technology development. The transformation needs to be treated differently according to the specific conditions of the manufacturer, and it is not possible to apply the hardware, otherwise the best purpose of increasing production and reducing consumption cannot be achieved.
Since the new drying and grinding technology and equipment have been used by users, they have been approved by users. However, in actual use, they still need to do the following in accordance with the actual situation of the user: 1 to strengthen the system to lock the wind, to ensure the ventilation effect; 2 Rationally design pipelines to minimize the resistance of the system, avoid piping collection, and ensure that the pipeline is unblocked. At the same time, pipelines, coarse powder separators and other insulation work should be done to prevent system condensation. 3 This technology makes full use of the original dust collector and separator of the mill system, and the purpose is to reduce one-time investment. If the original system dust collector is too small or it belongs to the eliminated equipment, it must be replaced. Otherwise, the expected effect cannot be achieved. 4 After the transformation using this technology, the output of the mill increases, the cyclic load increases, and the tail lifter increases. The transport volume will be one of the factors that restrict the output; 5 Strictly operate the system to ensure that the system's drying capacity and grinding capacity are balanced.
The traditional drying and grinding technology, simply put, the materials are dried in the grinding process at the same time, and the materials are crushed on one side and dried on the other side during the grinding process. As the material is highly dispersed and directly suspended in the hot gas stream, the heat exchange is rapid and the water evaporates quickly. At the same time, due to the higher wind speed inside the mill, fine powder and water vapor can be discharged in time, thus avoiding the sticking and grinding phenomenon, so the grinding efficiency is higher.
1. System process and main equipment According to the dust collection equipment used for raw material grinding, the closed-end raw material mill of high-voltage electrostatic precipitator is adopted for the grinding tail. The process flow is as follows: the high efficiency and environmentally friendly hot gas stove and the mixed fuel are added to the grinding head. The chamber supplies the heat needed to dry the raw material into the mill. The hot air enters the mill through a special grinding head feeding device and the material. The heat exchange occurs during the operation of the mill. The dust exhaust gas is discharged from the mill tail. The tube directly enters the dew condensation-type high-efficiency and low-resistance coarse powder separator to separate the gas and material. The separated dust gas enters the high-voltage electrostatic precipitator and is purified again. The purified gas is discharged into the atmosphere by the exhaust fan. The dust collected by the coarse dust separator has reached about 20% due to the 0.08mm square-hole sieve. Therefore, it enters the separator with the milled raw material to conduct powder selection, and is collected by the high-voltage electrostatic precipitator. The powder and the finished product selected by the separator are sent to the raw material warehouse via the conveying equipment. As the drying and grinding technology is adopted, the wind speed in the mill is increased, the flow velocity of the material in the mill will be accelerated, and the circulating load of the mill system will increase to about 300%.
1 grinding head drying oven. High efficiency and environmentally friendly hot gas stoves and mixed combustion chambers are used. The coal is first converted into gas in a hot gas furnace, and then sent into the combustion chamber through a pipeline. The secondary air is fully mixed and burned. Since there is always an open flame in the combustion chamber and the combustion air is sufficient, The gas can be quickly and completely burned, resulting in high heat generation and high thermal efficiency, low coal consumption, and low power consumption. At the same time, there will be no smoke generated after converting coal into gas, and environmental protection and sanitation will be achieved. In the absence of conditions, it is also possible to use an artificial coal-fired furnace. If it is operated properly, it can also be used for drying and grinding.
2 grinding structure. Therefore, the class mill belongs to the tail unloading lift wind sweeping mill. The section wind speed of 3 to 4 m/s directly extracts part of the fine particles out of the mill and enters the separator and dust collector for gas separation. Most of the material is discharged from the mill tail. Out, by the elevator into the powder machine. The raw material fineness requirements are mainly uniform particle size and do not pursue high specific surface area, so the fine particles and dried steam are directly extracted from the mill, eliminating or reducing the resulting bond, adsorption, material matting factors, and reducing the The phenomenon of grinding, so that the mill in the high cycle load to fully display its ability to achieve the purpose of increasing the output of the mill. The inner lining plate of the mill adopts a stepped lining plate and a small corrugated lining plate according to the requirements of the drying mill, and the gradation of the ball segment is appropriately adjusted to ensure the balance between the two silos of the mill. At the same time, it is necessary to make appropriate alterations or replacements to the original mill diaphragm plate and discharge plate to meet the requirements of the wind sweep mill. In addition, the process requires a maximum particle size of <10mm.
3 Dust removal system. Most small and medium-sized cement companies in China generally use high-pressure electrostatic precipitators and air-bag pulse bag dust collectors as raw materials for the purification of tail gas containing dust. The dust collector is required to operate stably under the limit of 5% to 6% of gas moisture content and maintain low resistance to reduce the power consumption of the system. At the same time, due to the drying and grinding technology requirements, the wind speed inside the mill is higher and the ventilation volume of the system is increased. Therefore, when using the existing dust collector, it is necessary to take into account the situation after the technical reform, otherwise the dust collection system is difficult to operate normally. Therefore, in order to make full use of the existing dust collector to reduce the one-time investment, high-efficiency, low-coarse-powder separators should be used to pretreat the grinding gas in order to ensure that the tail dust collection meets the drying wind sweeping grinding technology requirements.
2. Problems to be solved when using the new drying and grinding technology and equipment The new drying and grinding technology and equipment are particularly suitable for most of the shaft kiln cement companies in China, because most of the shaft kiln companies in China use small grinding machines (ie: φ1 The .8m, φ2.2m, and φ2.4m mills), after adopting this technology, can not only guarantee the production and quality of the shaft kiln production line, but also can use the cheap electricity and the grain price electricity to regulate the production and achieve energy saving. Reduce consumption, achieve good economic and social benefits. At the same time, it can also meet the needs of large-diameter shaft kiln technology development. The transformation needs to be treated differently according to the specific conditions of the manufacturer, and it is not possible to apply the hardware, otherwise the best purpose of increasing production and reducing consumption cannot be achieved.
Since the new drying and grinding technology and equipment have been used by users, they have been approved by users. However, in actual use, they still need to do the following in accordance with the actual situation of the user: 1 to strengthen the system to lock the wind, to ensure the ventilation effect; 2 Rationally design pipelines to minimize the resistance of the system, avoid piping collection, and ensure that the pipeline is unblocked. At the same time, pipelines, coarse powder separators and other insulation work should be done to prevent system condensation. 3 This technology makes full use of the original dust collector and separator of the mill system, and the purpose is to reduce one-time investment. If the original system dust collector is too small or it belongs to the eliminated equipment, it must be replaced. Otherwise, the expected effect cannot be achieved. 4 After the transformation using this technology, the output of the mill increases, the cyclic load increases, and the tail lifter increases. The transport volume will be one of the factors that restrict the output; 5 Strictly operate the system to ensure that the system's drying capacity and grinding capacity are balanced.