INDUSTRIAL Filters and Fabrics is a market leader in industrial filtration by catering to everything right from non-woven fabric manufacturing, making of filter bags, cages and accessories. Three decades of versatile experience and technical expertise in the field of industrial air pollution control systems is something that sets apart IFF from other manufacturers. IFF TSS (Technical Support Services) division had many more opportunities to take up challenges of non- performing bag filters and bag houses installations.
Case study 1
Cement Plant-RABH for kiln+raw mill; Cement plant in South India
The bag house (RABH) was facing problem of continuous stack emission and failing of glass fabric bags in all 14 modules. This bag house was designed and commissioned by reputed OEM But, from beginning visible constant emission and cause of bags` failure couldn't get identified. The nature failure of bags was at the anti-collapsible rings and most of the bags were found damaged in front of RA duct which opens in the module. Also, uneven distribution of gases in all modules and excessive bags tensioning was found to be an additional reason.
*Design Flow 7,62,120 m3/hr @ 220-240 0C
*Air to Cloth Ratio 0.416
*Inlet Dust Loading 60gm/Nm3
*Baghouse Type: Reverse Air
*Bag Quantity 3192 pcs
*Bag Dimensions 305mm X 10.82 mtr.
IFF Technical Support Services (TSS) analyzed the problem of bags` failure and took immediate action. All the modules were checked for damaged bags and replaced with new IFF- make bags. The modules were checked for leakages in tube sheets and thimbles. All the bags were removed and re-oriented and re-fixed with proper tensioning of 34 PSI(Originally-40PSI) and bottom bag clamping was also re-fixed.
IFF supplied 1,200 new bags which were replaced as against imported failed bags. The mechanical modifications at inlet gas distribution screen and RA opening duct in module was main change carried out as per the new design inputs and recommendations given by IFF.
After attending to the above suggested modifications points and under supervision of IFF TSS team, the emission from stack was reduced to practically zero. The DP of the bag house was also under control and in between 130-150 mmwc. After three months of operation, the continuous failure of bags phenomenon stopped and overall performance of bag house was observed / reported to be satisfactory by plant head.
Case study 2
10 TPH boiler-bag filter Site:
A mega steel plant, Western India
A mega steel plant was facing the problem of performance in the boiler bag filter for the past 5-6 years. The problems were as follows:
1 Boiler in operation frequently exerts backfire.
2 The DP of bag filter always remains high [250 mmwc-300mmwc].
3 The dust from bag filter was not dislodging and was found stuck on bags.
4 In the bag filter, most of the bags near the outlet were failing due to improper gas distribution and at the centre, the bags were getting damaged frequently.
5 The life of fabric bags were a maximum of 6-8 months.
*Design Flow: 27,500 M3/HR.
*Air to Cloth Ratio 1.35
*Inlet Dust Loading 10-20 GMS/NM3
*Baghouse Type: PULSE-JET
*Bag Quantity: GLASS + MEMBRANE
*Bag Dimensions : 149 X 3650 MM
IIFF studied the design and actual parameters and conducted internal inspections of the bag filter.
A detail report of internal mechanical modifications was explained to plant operations with supporting drawings. The inlet gas distribution was modified in such a way that gases were equally distributed in entire bag house. IFF- recommended internal mechanical modifications were carried out onsite under supervision of the IFF TSS team. One set of glass+ membrane bags as against bags was supplied and cages were reconditioned.
The bag filter was re-commissioned after a long shutdown of 30 days. The results were recorded as follows:
1 First, boiler sudden backfire was stopped; even boiler was taken on full load.
2 The DP of bag filter was checked during boiler full load and recorded a maximum of 50-55 mmWC as against 200-25 mmWC.
3 Before revamping, no dust was dislodging from bags. But now in a day, 11 tonnes of fly ash was found continuously discharged.
4 The stack emission was checked for boiler in full-load and observed emission of less than 18 mg/nm3.
5 I/D fan power savings by 4.5 KW/Hr & by DP reduction has gained Rs1113/- per day. So, within one year of operation, client could able to recover cost of IFF supplied bags.
6 Also, ambient air quality and environment in the boiler house was found improved drastically.
Case study 3
Cement Plant RABH- for kiln + Raw mill application
Cement plant in South (India)
The bag house was facing problem of continuous failure of glass fabric bags and constant high emission of 2gms/nm3 from stack. The emission and bag failure problem was detected since this bag house was installed and commissioned. The bags were originally supplied found variations in lengths. Bag- to- bag friction, internal supporting structure fouling with bags, and sagging of bags was noticed.
*Design Flow 9,35,000 m3/hr @ 220-240 0C
*Air to Cloth Ratio 0.44
*Inlet Dust Loading 50 gm/Nm3
*Baghouse Type: ReverseAir
*Bag Quantity 3696 pcs
*Bag Dimensions 292mm X 10.37 mtr.
IFF rectified around 3,000 bags of imported make installed bags which were in extra dia and length. IFF Technical Support Service (TSS) visited site, studied and analyzed problem of the bags` failure. All 3996 nos bags were removed and checked modules for mechanical healthiness.
The modules, inlet/outlet ducts, RA ducts and all mechanical abnormal points were attended which were left out during installation. All modules leak test was carried out and proper fixing of bags was done under supervision of IFF TSS. IFF- altered bags were re-installed and proper tensioning was done. The internal bag fouling with thimbles were made blind. IFF TSS conducted technical session of RABH operations in connection with doÆs and donÆts in process, mechanical, instrumentations and control logic to plant operations.
After successful re-installation of bags, a proper pre-coating was done and the bag house was taken on load. Initially stack was puffing but within 24 hrs, stack got clear. The DP of bag house was also observed under control of 130-160 mmwc.
The kiln was taken on a hundred per cent load and found stack is visually clear and DP is always less than 150mmWc. The emission measurements were taken and recorded at <20 mg/nm3.
Industrial Filters & Fabrics offer diagnostic solution for the filter bags, cages and accessories for dust collectors.
S.W.Satpute is with IFF as VP , Technical and field services. Web site: www.iffgroup.com email : email@example.com, firstname.lastname@example.org