Technical transformation of flue gas purification

2022-07-26
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Abstract: Gore company is responsible for the technical transformation of the bag type dust collector at the kiln end of Shanxi Cement Plant. It has been nearly two years since the transformation was completed in September 1997 and has been in operation. According to the test and analysis of the strength of the filter bag during the latest overhaul, the expected service life of the filter bag can reach more than five years

I. preface

according to the "process flow of 2000 ton rotary cement kiln tail flue gas purification system in Shanxi Cement Plant and the design requirements and parameters of relevant dust removal equipment" provided by the production and Technology Department of Shanxi Cement Plant, Gore filter products (Shanghai) Co., Ltd. and the company's technical experts in flue gas treatment in cement plants in the United States, Singapore, South Korea, etc, Based on the successful experience of Gore company in the extensive application of Gore-Tex membrane filter material in the flue gas purification and dust removal equipment of foreign cement plants, and the basic point of preliminary analysis and Research on the use of the counter blowing bag type dust collector at the kiln end of the rotary cement kiln in Shanxi Cement Plant at present, press the button to start the experiment. At the beginning of the experiment, Gore company was responsible for the technical transformation of the bag type dust collector at the kiln end of Shanxi Cement Plant, It has been nearly two years since the transformation was completed and put into operation in September 1997. According to the test and analysis of the strength of the filter bag during the latest overhaul, the expected service life of the filter bag can reach more than five years

II. The transformation basis for the reverse blow large bag dust collector at the end of the rotary cement kiln with Gore-Tex membrane filter bag

2. 1. Main technical parameters

2. 1. Technical requirements and working conditions for flue gas purification of the dust collector at the end of the rotary cement kiln in Shanxi Cement Plant

1. Treatment air volume of flue gas purification: 423000m3/hr.

2. Filter bag size: Φ three hundred × 9300mm

3. Number of originally designed filter bags: 2208

4. Filter compartment of dust collector: 16 rooms

5. Filter speed of originally designed dust collector: 0.36m/min (full operation) 0.39m/min (when one room is cleaned)

6. Dust inlet concentration: ≤ 80g/nm3

7. Flue gas temperature: <250c

8 Emission index requirements: ≤ 100mg/nm3

2, 1, 2 cement plant rotary water main characteristics of mud kiln tail dust on May 4:

generally speaking, the main characteristics of cement plant rotary cement kiln tail dust are:

fine particle size (average dust particle size μ); High humidity; The flue gas temperature is high and fluctuates greatly; And high dust inlet concentration

2, 2 cement plant rotary cement kiln tail gas purification and application of membrane filter bag type dust collector

clinker calcination is an important process link in cement production, and its main pollutant is high-temperature and high concentration dust-containing flue gas. Its dust emission can account for about 70% of the total dust emission of the whole cement plant. At present, most domestic cement plants use electrostatic precipitator for dust removal, which is characterized by low running resistance; It has strong overload operation ability and relatively easy operation and management. However, the electrostatic precipitator must conduct conditioning treatment on the flue gas to improve its dust removal efficiency. If the dust emission control requirements are strict (i.e. reach the level of less than 50mg/m3), even if the equipment investment and operation cost of the electrostatic precipitator are greatly increased, the various test indicators of flame retardant PP products used in socket parts are shown in Table 2, which are difficult to meet the dust emission requirements. Therefore, in recent years, many large cement plants in North America and South Korea have transformed electrostatic precipitators into bag filters. In addition, the existing cement manufacturers not only require to control dust emission, but also hope to continuously increase production, reduce production energy consumption and reduce production costs. Many application examples are measured with high-precision sensors. After the gore-ex membrane filter bag is selected for the flue gas purification dust collector at the tail of the rotary cement kiln in the cement plant, the technical, environmental and economic benefits are very significant

2.3 main problems existing before system transformation

a BFRs type reverse blow bag dust collector is shared by the 2000t new dry process ultra short kiln (diameter 3.962m, length 42.672m) of Shanxi Cement Plant and lm32.40 leicher mill (output 160 tons per hour). From november1995 to october1996, although the system output was only 50 tons per hour, the domestic glass fiber filter bag selected in the original design began to suffer a large number of damage, and the emission concentration seriously exceeded the standard. With the increase of kiln system output and system air volume, the pressure difference of

dust collector rises to 1800pa under the condition that the raw mill and kiln operate at the same time; When the mill stopped and the kiln operated alone, the differential pressure of the dust collector soon reached the limit alarm value (2750pa), and the kiln system was under positive pressure, which seriously affected the normal production of the kiln. By April, 1997, all filter bags were damaged, and the dust collector had lost its dust removal function. Therefore, Gore company was responsible for the transformation of the dust collector in September, 1997, and Gore-Tex membrane filter bag with "surface filtration" function was selected

III. After Gore Tex membrane filter bag is selected, Gore filter products (Shanghai) Co., Ltd., as the filter bag Hongying supplier, can provide Shanxi Cement Plant with the operation technical guarantee of Gore Tex membrane filter bag dust collector equipment. That is, under the overall, technical and test conditions agreed by both parties, the following main technical performance indicators can be achieved within the service life guarantee period:

1. The air volume measurement is not lower than the original design value, i.e. 423000m3/hr.@ 250 ℃

2. Filter bag size: ф 300X 9300mm

3. Number of filter bags: 1152

4. Filter compartment of the dust collector: 16

5. Filter speed of the dust collector: 0.70m/min (full operation) 0.75m/min (one room dust removal)

6. Dust inlet concentration: ≤ 80g/Nm3

7. Flue gas temperature: <250 ° c

8. Emission index requirements: ≤ 30mg/nm3

9. The working resistance of filter bag shall always be lower than 150mm water column; The average resistance is 100 mm water column

10. The expected life of the filter bag is five years

Description:

* because Gore-Tex membrane filter bag has excellent dust removal and good air permeability, under the condition that the original dust removal capacity of the cement rotary kiln dust collector remains unchanged, the filter bag filtration speed of the dust collector can be increased from 0.36 to 0.70m/min after changing the bag, that is, the number of filter bags can be reduced by about 50%. That is to say, at present, 138 ordinary filter bags used in each compartment can be reduced, and now only 72 Gore Tex books need to be installed

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