Low Pressure Roto Pulse Advance Bagfilter for Steel Industry

Transcription

1 Low Pressure Roto Pulse Advance Bagfilter for Steel Industry Sasanka Bhattacharya, Director (Chemical), GEA Process Engineering (Pvt.) Ltd. Abstract GEA Process Engineering (Pvt.) Ltd., over the years, has introduced a latest technology for dust seperation from the dirty gas, now in use in most of the steel industry in advanced countries. GEA has sucessfully installed and run such units with a max. capacity of 2,000,000 m 3 /hr in casthouse and stock house of Thyssenkruup plant in Duiesbarg, Germany. Continuous development in GEA laboratory in Frankfurt, Germany has made this bag filter the 1 st choice of steel Industry in Europe. In India, GEA has already sucessfully instlalled such a baghouse for high dust laden gas in a cement palnt with min. imported component. This technology has numerous advantage over the conventional technology as below. Configuration Modular, multi-compartment design - Easy to enhance the capacity in min. time. Bags in compartments are arranged in concentric circles - More bag per m 2 area. Single pulse valve for as many as 400 bags and single manifold per compartment Low inlet velocity of raw gas into compartments ensures good flow distribution and low pressure drop Concentric bag bundle facilitates gas distribution upwards along the compartment corners and cross-flow into the bags Gas velocity between bags remains sufficiently low to minimize dust re-deposition and potential bag erosion Low pressure pulsing Cleaning air is at low pressure of 0.7 to 0.8 bar - delivered by simple roots type blower (versus 3 to 6 bar conventional systems) Cleaning arm rotating 1/3 RPM - small geared motor and manifold fitted with nozzles injecting air into filter bags Cleaning air volume comparatively large so bags are back flushed in addition to dynamic Bag dimensions: diameter 0.15 m, length 4 to 8 m Higher bag life due to soft cleaning & soft landing of bags on the cage Smaller foot print due to elliptical bag configuration & less civil work Easy maintenance, min. manpower requirement Keywors : Bagfilter, low pressure pulsing, bag cleaning

2 Emission Control Unit India GEA Product Portfolio Active in environmental protection since 1897 More than gas cleaning units all over the world GEA is certified according to ISO 9001 : 2000 and SCC Introduction to GEA Emission Control India GEA Emission Control India is a S.B.U of the GEA Process Engineering Ltd. head quartered in Vadodara. The headquarter employs more than 200 engineers and serve as back-up for the division located in Thane. The GEA Emission Control India will work close with the GEA Emission Control Technology Centers at Essen, Germany and Copenhagen, Denmark. The particulate market will be supported by GEA Bischoff (Former Lurgi Bischoff) in Germany active since approx. 100 years - and a long history in this market.

3 Low PressureFabric Filtration Design (I) Benefits: Easy Maintenance (II)

4 Walk-in plenum Spacey Accessible Large bag bundles Low number of parts Small access doors, easy to tighten Bag change without tools No dismantling of blow pipes All parts easily accessible Bag Cleaning Low pressure cleaning system Economical for large gas flows Pressure 0.8 bar, large volume (back flushing) No venturi tubes required

5 All typical applications Cleaning phase Filtration inhibitation Cloth acceleration Cloth deceleration Dust deposition Rinse of cloth Repositioning of bag Each bag is cleaned max. 10 times/h, PTFE (3 times/h) Benefits: Easy maintenance (I) Modular multi-compartment Single pulse system per compartment Walk-in plenum Heavy duty manifold bearing design Accessible from outside Configuration Modular, multi-compartment design Bags in compartments are arranged in concentric circles Single pulse manifold per compartment Dust laden gas enters the hopper via the inlet damper in a downward direction which promotes pre-separation of the coarse dust particles Low inlet velocity of raw gas into compartments ensures good flow distribution and low pressure drop Concentric bag bundle facilitates gas distribution upwards along the compartment corners and cross-flow into the bags Gas velocity between bags remains sufficiently low to minimize dust re-deposition and potential bag erosion

6 Low pressure pulsing Cleaning air is at low pressure 0.7 to 0.8 bar - delivered by simple roots type blower (versus 3 to 6 bar conventional systems) Cleaning arm rotating 1/3 RPM - small geared motor and manifold fitted with nozzles injecting air into filter bags Cleaning air volume comparatively large so bags are back flushed in addition to dynamic cleaning Venturi tubes at bag inlet not required Cleaning nozzles on manifold located so no adjacent bags are cleaned simultaneously - minimizing dust redeposit ion Bag dimensions: diameter 0.15 m, length 4 to 8 m Low pressure filtration for clean gas dust concentration below 2 mg/nm 3 (dry) Main parameters influencing clean gas dust concentration Agglomeration of particles (known for cementprocess) Filter medium (known for cementprocess) Air to cloth ratio Frequency of pulse Pressure of cleaning air

7 Conversion of ESP to Low Pressure Jet Pulse (I) Change of technology from ESP to bag filter required due to changes in incineration process, emission limits and high CO levels Several number of GEA references Completion of work can be made in standard plant shutdown in less than 4 weeks time Experience in Low Pressure Fabric Filters More than 40 units installed in the Cement Industry Kiln / raw mill Clinker cooler Bypass Coal mill Each for more than 200,000 m 3 /h. Biggest 2,000,000 m 3 /hr. Various installations in the steel and non ferrous industry Secondary Dedusting for Steel workshop Cast house Copper smelter Advantages Overall low energy consumption Highest reliability Easy maintenance Proven design Very low emmission gurantee possible (2 mg/nm 3 ) Low investment cost for large installation