PPC type air box pulse bag filter is a _ horizontal level _ rate dust collector. It combines the advantages of various types of baghouse dust collectors, such as backflushing and spray pulse cleaning, and overcomes the shortcomings of insufficient backflushing dust removal and simultaneous pulsed phase cleaning. Therefore, the application range of the bag dust collector has been expanded. Because the structure of this type of dust collector has its own characteristics, the improvement rate and the service life of the filter bag are prolonged.
PPC type air box pulse bag dust collector can be widely used in the crushing, packaging, storage roof, clinker cooler and various mills of cement plants for dust collection systems. Measures, the structure of the dust collector is changed accordingly, and it is also suitable for the dust collection of gas with extremely high dust concentration, such as the grinding system with O-Sep powder washing machine, the gas dust concentration is higher than 1000G / M3. The dust collector can collect dust without cyclone dust collector. In addition to being used in the cement industry, it is also suitable for dust collection of waste gases such as metallurgy, chemical industry, machinery and civil boilers. The material of this series of dust collector filter bags is polyester needle felt, and the allowable temperature is less than 120 ℃. If the filter bag uses aramid needle felt, its allowable use temperature can reach 210 ℃. But this material is expensive. If the temperature of the exhaust gas to be processed is higher than the allowable temperature of the filter material mentioned above, cooling measures shall be taken before the exhaust gas enters the dust collector.
PPC-type air box pulse bag filter is an outdoor type composed of different numbers of rooms and different number of bags in each room.
There are four types of bags per room: 32, 64, 96 and 128 bags. There are 33 specifications in the whole series. The filter bag diameter is 130mm and the filter bag length is 2450mm and 3060mm.
PPC type air box pulse bag filter can operate in negative or positive pressure, the basic structure is unchanged, its dust collection efficiency can reach above 99.9%, and the dust concentration of the gas after purification is less than 100MG / M3. This series of dust collectors The main technical performance is shown in Table 2, Table 3 and Table 4, respectively. If this series of dust collector is used in cold areas, when the outdoor heating calculation temperature is -25 ° C, if a heating device is to be added, the housing of the dust collector must also be changed accordingly.
Structure and working principle:
PPC type air box pulse bag filter is composed of shell, ash hopper, ash discharge device, bracket and pulse ash cleaning system. When the dust-containing gas enters the dust collector from the air inlet, it first encounters the inclined baffle in the middle of the air inlet, and the airflow turns to flow into the ash hopper. At the same time, the airflow speed becomes slow. Due to inertia, coarse particles of dust in the gas directly fall into the dust. The ash hopper plays the role of pre-dust collection. The airflow entering the ash folds and passes upwards through the filter bag with a metal years frame inside. The dust is captured on the outer surface of the filter bag, and the purified gas enters the upper part of the filter bag room. In the clean room, the air inlet of the FMQD32 dust collector that is collected by the air outlet pipe is set on the ash hopper. After the airflow enters the ash hopper, it first hits the baffle at the end of the air inlet pipe. Its function is the same as the above principle. The shell is divided into several independent dust collection chambers by partitions, and each dust collection chamber is cleaned in turn according to a given time interval. Each dust collection room is equipped with a poppet valve. When the dust is cleaned, the poppet valve is closed to cut off the filtered air flow through the dust collection room. Then the pulse valve is opened and high pressure air is sprayed into the filter bag. dust. The pulse blowing width and dust cleaning cycle of each dust collection chamber are automatically and continuously performed by a dedicated dust cleaning program controller.
Third, the difference between air box pulse dust collector
and spray pulse bag dust collector:
The characteristic of the spray pulse bag type dust collector is that in the same dust collection room, each row of filter bags sprays the dust in turn, and the dust collection and filtering is performed during the dust cleaning, which is called online dust cleaning. Part of the dust blown by this cleaning method will be captured again by the adjacent filter bag.
This phenomenon is more serious if it is used to trap gas with a large concentration of dust, so the application of the spray pulse dust bag cleaner is limited.
The characteristic of PPC type air box pulse bag filter is that it adopts separate compartments to perform ash cleaning, which is called offline ash cleaning. When blowing dust in a certain room, the filtering airflow is cut off, avoiding the secondary flying of dust caused by blowing dust. Therefore, the air box pulse bag dust collector can capture gas with a moisture content and dust concentration of up to 1000G / M3.
Generally, according to the main technical parameters of the gas to be handled at the dust source point, such as air volume, gas temperature, and dust concentration, etc., the selection is performed according to the following steps.
1. Calculate the net filter area of the dust collector according to the following formula according to the amount of processing gas:
F = Q / 60VN （㎡）
In the formula: Q——Processing gas amount (M3 / H)
VN—Net filtering wind speed (M / min)
Table 1 shows the recommended net filtration wind speeds of the main dust sources in the cement plant. The so-called net filtering wind speed and net filtering area refer to the filtering wind speed and filtering area when a certain room stops filtering and performs ash cleaning.
2. According to the calculated net filtering area, you can directly select the appropriate dust collector from Tables 2, 3, and 4.
3. Selection example:
Example 1. A 3.5 × 12M cement mill with a ventilation capacity of 30,000M3 / H and a gas temperature of 110 and a gas concentration of 150G / M3, a FMQD bag dust collector was selected.
(1) According to the given air volume of 30000 M3 / H, the net filtering wind speed of the cement mill is obtained from Table 1, VN is 1.5M / MIN, and the net filtering area is calculated according to formula (1).
F = Q / 60 · VN = 30000 ÷ 60 × 1.5 = 333 （㎡）
(2) It is known from the table that the net filtering area of FMQD-7 is 372㎡, which is close to the calculated net filtering area of 333㎡, so the FMQD64-7 dust collector can be selected. Because the net filtering area of FMQD96-5 is the same as the net filtering area of FMQD64-7, FMQD96-5 dust collector can also be selected. As for which model is more reasonable, the user can determine according to the geographical location of the dust collector. If the length is long and the width is narrow, FMQD64-7 with more rooms can be used. Otherwise, the number of rooms is selected. Fewer FMQD96-5 dust collectors.
Example 2 The daily cooling rate of the clinker grate cooler of 2,000 cement plants per day is 32,000 M3 / H. Try to choose a FMQD bag dust collector.
(1) According to the air volume of 32000 M3 / H and the net filter wind speed VN of the grate cooler found from Table 1, the net filter area is 1.7M / MIN.
F = Q /60·VN=320000×60÷1.5 = 3137 (㎡)
(2) It is known from Table 4 that the net filtration area of FMQD128-210 is 2959㎡, which is less than the calculated net filtration area of 3137㎡, but the net filtration wind speed increase is not much, less than 6%, so FMQD128 -210 dust collector is suitable.
Five, model description:
FMQD XX ------- a × b
F means: air box type; M means: pulse; Q means: dust collector;
D means: screw conveyor, air conveying chute; XX means: number of filter bags in each room;
a indicates: the number of columns (single column is not marked); b indicates: an example of the number of rooms in each column FMQD96-2 × 5 indicates a double-row ten-room 96-bag air-box pulse bag dust collector (the ash discharge device is Screw conveyor).
Six, dust cleaning electrical control device:
1. Ash cleaning electrical control device The dust cleaning control method generally adopts the timing method, and the constant resistance method can also be used. The so-called constant resistance method is to control the pressure difference between the inside and outside of the filter bag. When the differential pressure value of the dust collector reaches a set value (generally 1470Pa). That is, the signal is sent from the differential pressure transmitter, and the dust is cleaned room by room according to the established procedure through the electrical control device.
2. The function of the electrical control device adopts a single-chip microcomputer for centralized control of the multi-room dust collector. The control has two methods: automatic and manual. When the single-chip microcomputer fails or is overhauled, it can be switched to manual control at any time. Equipment maintenance is provided with on-machine control.
3. The wiring design of the dust cleaning electrical control device to the dust collector's incoming terminal is the responsibility of the user. For the connection terminals, refer to the dust cleaning electrical controller manual. The wiring of the dust collector inlet terminal to each solenoid valve is the responsibility of the manufacturer.
1. The main body of the dust collector includes the shell, ash hopper, inlet and outlet ducts of the filter bag device, ash exhaust device and pulse injection system (including pulse valve, pipeline, valve, triple gas source and gas storage tank, etc.).
2. According to different specifications, it can be shipped as a whole or disassembled. The basic design is the responsibility of the user.
3. The dust collector is equipped with an electric control device for dust removal, which is generally controlled according to the timing of dust removal. If the user requests to order according to the constant resistance control, it should be noted that the charges for the differential pressure gauge, differential pressure indicator alarm and other instruments of the constant resistance control shall be calculated separately.
4. For the series products, the equipment use and installation instructions are provided by the manufacturer.
5. The power supply and distribution of the ash unloading device of the series products are designed by the user.