In the building materials industry, coal mill using baghouse dust collector has been widely used, but due to the development of coal mill equipment, coal transportation has been canceled powder separator, and by bag filter (baghouse ) chief Instead, by and baghouse inlet concentration increased significantly, the original MDC, HMC-type bag filter, etc. are not competent, and its original explosion venting valve there are many problems. Yancheng million Jorda company accordingly conducted research, developed a new generation of coal mill baghouse JQM and technical appraisal meeting chaired Yancheng Technology Bureau was adopted, the conclusion is the level of technology is the leading domestic level. First, the characteristics of the coal grinding mill coal flue dust contained in the flue gas for coal, large concentrations of fine granularity, flammable and explosive. 1, several characteristics of pulverized coal: coal, according to research department tests show a, bituminous coal powder explosion limit explosion limit concentration: 110 ~ 335g / m3, the explosion limit concentration: 1500g / m3. Anthracite explosion limit concentration: 45 ~ 55g / m3, the explosion limit concentration: 1500 ~ 2000g / m3. b, pulverized coal particle size may Explosion: up to 0.5 ~ 0.8mm, grains smaller than 75μm easier by blasting. c, pulverized coal ignition temperature: 500 ~ 530 ℃, self-ignition temperature: 140 ~ 350 ℃. d, volatile anthracite coal volatile matter ≤10%, no danger of explosion. Volatile bituminous> 10%, the risk of explosion, the greater the percentage, the greater explosive. 2, coal provided they have the following three elements, it may carry out a fire and explosion, not missing one: a, there is a pulverized combustible material; b, oxygen; c, fire 3, cement coal grinding process is traditional coal mill discharge containing flue gas to flow through the coarse coal powder separator and then the fine dust separator to the MDC, the dust concentration is low, about 70g / about m3. With the development of technology and progress, cancel powder separator, pulverized coal flue gas containing dynamic classifier (Classifier) ??after directly to the filter. At this time, the concentration of pulverized coal increased to 300 ~ 700g / m3, in a pulverized coal dust filled the space within the blasting is in range. The concentration of pulverized coal is very thin, large surface area, particle size <80μm accounted for about 80%; the addition of a cement plant now uses bituminous coal, volatility is generally 10 to 30%, also are in the blasting range. Furthermore, since the coal grinding mill belonging to drying, there is a certain moisture content in the flue gas dew point is generally 50 ~ 55 ℃, easy to condensation. 4, the concentration of oxygen in more than 15 to 17 percent, can lead to blasting, less than 14% considered as inert gas. Cement mill pulverized coal preparation system arranged in the kiln (kiln finger), as the use of flue gas kiln drying medium, low oxygen content in the flue gas, coal inhibitory effect on low flame proof requirements . When arranged in the kiln kiln cooler use or the use of hot air as the drying medium hot stove, hot air oxygen content will be up to 21%, with the blasting conditions. 5, ignition sources, coal mill whether spontaneous combustion of pulverized coal blasting or ignition temperature range? Cement coal mill inlet temperature is generally not more than 400 ℃, coal mill exit gas temperature above the dew point to avoid condensation need 15 ~ 30 ℃, the general control of 70 ~ 85 ℃, but the use of flue gas for drying kiln when used, sometimes because of the moisture content of up to 6%, coal mill flue gas outlet should be higher than the dew point temperature 30 ~ 35 ℃, the general control of 85 ~ 90 ℃. See its exit gas temperature in the fire or were outside the scope of self-ignition temperature. Second, advanced baghouse summary, coal mill flue volatile pulverized coal (bituminous coal), particle size, concentration were within the range of blasting, the oxygen content more likely to be in the development of the bag preventable type precipitators. Prevention focuses on the elimination of possible sources of ignition, followed by reducing the amount of dust in the air leakage, to avoid increasing the oxygen content of air entering, additional proof pressure relief valve. In the development of the pulverized coal dust can accumulate not allowed planes and corners, does not allow the accumulation of static electricity and sparks, mechanical transmission friction does not allow the existence of an impact, not allowed to have a hot surface, in order to prevent ignition sources. Yancheng one hundred million Jorda Environmental Protection Machinery Co., Ltd. developed advanced coal mill baghouse has the following characteristics: 1, using a high concentration, high pulse jet bag filter, coal mill model JQM type: this is dedicated to the development of coal mill and pulse dust collector, a combination of sub-room cleaning, pulse jet dust precipitator advantage with handling large concentration of dust, cleaning ability, high dust collection efficiency. Stop using offline compartment air pulse cleaning technology that can handle up to 1000g / m3 dust concentrations of dust and gas emission concentration ≤50mg / m3, for coal mill dust characteristics, using a number of flame-proof structures and measures. Dust workflow: Filter conditions: with gas from coal dust precipitator inlet duct box side by oblique partition steering evenly into each compartment hopper, large particles of dust due to inertial impaction and gravitational sedimentation and sinking hopper, turn off fine dust into the filter chamber with the air upward, is attached to the bag * sieved and its surface, the purified gas through the bag into the room through the sub-room cleaning bag and then by road from the total exhaust removal system The main fan sucked out through the chimney into the atmosphere. Cleaning conditions: With the continuous operation of coal dust layer filter working conditions, product constantly attached to the bag looks thickening flow resistance through gradually increased, when the resistance reaches the set value (such as 1470Pa), Ann providing a signal transmission device in the differential pressure (constant pressure control) on the filter, programmable controller (PLC) started, sequentially switched in turn instructs the sub-compartment of the poppet valve closed, open, switching impulse valve for each chamber stop the wind carried the bag pulse cleaning. First, as the first sub-chamber poppet valve closed, cutting off airflow through the dust, and then open the valve on the pulse of all the compartments were to stop the wind pulse cleaning bag, so the bag when internal and external pressure to return to the original filtration resistance, about 1 minute time interval, so that coal dust cleared after settling down, then open the poppet recovery room of the first sub-filter. Each compartment in cycles sequentially cleaning, until finally finished cleaning a room. PLC programmer can also be manually controlled or timed. 2, the design of a set of advanced flame-proof technical measures a, body structure is designed to prevent the accumulation of dust inside the components of pulverized coal, eliminating fouling of the plane, setting up dust board, the board of the slope is greater than 70. Hopper cone angle of each compartment is greater than 70, the angle between the two walls of a hopper bucket of fouling too easy, plus the adjacent sides of the plate weld slide plate, rounded to increase space and eliminate the deposition of pulverized coal. Taking into account the moisture content of the flue gas due to improper operation or high, sometimes low temperature condensation forming inside the pulverized coal hopper blockage in the hopper hopper walls, additional electric heating devices and insulation. To prevent the bottle inside the hopper feed, in the hopper wall also set up warehouse wall rapper. With large capacity hopper under cinder valve. b, with a bag filter selected, taking into account the filter, a high concentration of pulverized coal and air flow friction on the impact of friction bag in the bag surface is easy to produce static electricity, the accumulation of static electricity can cause sparks and blasting. While also taking into account the high moisture content in the flue gas of coal grinding characteristics selected to eliminate static bag waterproof anti-oil Antistatic Polyester needle felt filter with conductive fibers and dust taken overall grounding. c, flame-proof pressure relief valve designed to prevent injuries and damage to coal combustion dust explosions, pressure relief valve is provided in the side precipitator. The pressure relief valve in the past to use more simple style or broken plate hammer, its main drawback is that after the explosion, the pressure relief valve port open, dust can not continue to work, and the relief pressure is difficult to control. Now precipitator design a new type of pressure relief valve with double safety lock, which set a **** piece seal with safety lock and door double-layer structure. In peacetime security door is closed, when the case of an explosion, **** disc rupture, safety door locks by dust inside the enormous pressure to open the top to relieve pressure, after pressure relief safety locks automatically shut down to prevent the sealing pressure relief port leakage. Safety lock release force can be adjusted by the size of the spring, according to sealed door locks facade layout size 4 to 6 months. **** Piece uses requiring high accuracy pressure ****, large discharge area, sealing, corrosion-resistant, sensitive, safe and reliable. **** Commonly used pressure 0.01MPa. To ensure the quality, safety and reliability, venting pressure accurately, **** piece selection of professional manufacturers (such as security equipment factory) **** piece of stainless steel. d, precipitator filtration velocity should use ≤1.0m / min e, in order to ensure the seal, the leakage rate should dust <3%, the smaller the better, to avoid too much oxygen into the dust. Monitoring f, pressure and temperature in the dust filter chamber pressure monitor located at the outlet of the precipitator ash hopper set temperature monitoring. g, other security measures: For large coal mill dust and conditional manufacturers require export precipitator installed CO detector, and is equipped with fire fighting equipment CO2 or N2. On the one hand you can always detect the concentration of CO, on the one hand but also automatic alarm when CO concentration limit blasting, in the event of combustion can be controlled to open fire extinguishing equipment in the control room or remote site to filter out the fire at the internal combustion to avoid situations explosion. h, in the maintenance and management requirements for manufacturers to strengthen the management and maintenance of dust, especially to strengthen the control of fire, to strengthen and coarse dust separator cinder inspection, so that the two are not too many remaining in the hopper coal, in order to avoid the spontaneous combustion of pulverized coal. For more information you can call our service hotline, you can also visit our official website for more information www.rdlhbsb.com!