Efficiency of Fabric Dust Filter (Bag Filter) in reducing Suspended

Particulate Matter level.

PRESENTED BY UMANG K. SHAH

Introduction Textile industry is one of the largest sources of air pollution.M/s. Dada Silk Mills (M/s. DSM) where the study was conducted is located in Surat, Gujurat. There are around 70 units of textile processing in Sachin, 110 in Pandesara and apprximatey 60 units in Kadodara making Gujurat a textile processing hub.The company had installed a Steam Boiler with steam generating capacity of 4 tonnes per hour and a thermic Fluid Heater with heat generating capacity of 20,00,000 kcal/hr.

In the above utilities, they used Indonesian Coal and Lignite as fuel and the desired quantity of of steam/heat is obtained by combustion of coal.

This resulted in the generation of particulate matter, SOx and NOx through stack which causes air pollution.

For controlling this emission a mechanical dust collector and bag filters were installed to conform to the GPCB norms of PM production less than 150 mg/Nm3

Steam Boiler

Make M/s. Zenith Thermal equipments pvt.ltd.

Capacity 4.0 TPH

Rated pressure 10.50 kg/cm2

Type of Boiler Package type

Type of fuel Firing

Manual firing

Rated pressure 10.50 kg/cm2

STEAM BOILER

Thermic Fluid Heater

Make M/s. Gujtex Engineering, SuratYear 2013

Capacity 20,00,000 Kcal/hr. (2,000 U)

Type of fuel Firing Manual firing

THERMIC FLUID HEATER

Flow diagram of APCM attached with Steam Boiler (4.0 TPH) & Thermic Fluid heater (20,00,000 kcal/hr)

APC measures

Parameters Unit of Measurement

Dimensions

Mechanical Dust collector

No. of cones Nos. 36

Diameter of cones

mm 250

Length of cones

mm 305

MECHANICAL DUST COLLECTOR

Need for studyThe mechanical dust collector and bag filter was lacking in efficiency and economy and hence caused trouble for the textile mill to meet the Govt. regulations.The type of Bag Filters used was fiber glass which could not resist high temperature and resulted in bursting.On an average 25 bags were being replaced in a year causing a huge economic loss to the textile mill with no significant improvement on the environmental side of it as well.

DESIGN OF NEW BAG FILTERS

BAG FILTER

Umang standing beside apparatus used for calculating the SPM level.

Bag filters are usually called Fabric Dust Collectors that are used in Industrial units for separating dust particles from dusty gases.

The new Bag Filter was equipped with Automatic Inlet Cum Bypass Damper System (ICBD).

The system automatically stopped the incoming flow of hot flue gases; therefore the Bag Filter could not reach its maximum resisting temperature of 250°C.

M/s. DSM is using their Bag Filter since past 11 months and no bag is replaced so far. They have set the Inlet Cum Bypass Damper system currently at 220°C.

SPM CalculationThe Suspended Particulate Matter (SPM) level was determined by Gravimetric Method with reference to IS 11255 (Part 1) – 1985. The various apparatus used were Digital Weight Balance, Glass Fiber thimble and Desiccator. The Initial Weight of thimble (W1) was found, and then we found Final Weight of thimble after collection of Particular Matter (W2). The SPM level was found by dividing (W2-W1) by total volume in liters.

Equation

Results and DiscussionThe SPM level significantly dropped down from 138.6 mg/Nm3 to 88 mg/Nm3 after adopting new Bag Filter. Due to reduction in dust load, and proper design of Bag Filter, the air pressure required to clean the Bag Filter are very less i.e. 3.5kg/cm² instead of 6kg/cm² which were required earlier. The quantity of smoke emission has reduced. The smoke emitted from stack is almost white now. Less manpower required. Suspended particles up to 10μm can be filtered. Residents living nearby can breathe peacefully.

It is concluded that after implementation of New Bag Filters the Particulate Matter (PM) level was under control i.e. 88 mg/Nm3 as compared to previous which was 138.6 mg/Nm3.

The smoke emitted through stack is almost white. The electricity consumption has been reduced approximately by 7%.

Fibre glass is an appropriate filtering bag material in Bag Filter for textile industries. Suspended particles of size up to 10 μm are filtered in Bag Filter.

The fuel consumption has been decreased by approximately 3%. There is a need to create awareness among textile industries to use efficient air pollution control equipment’s there by reducing air pollution.

Acknowledgements We would like to thank our guide and mentor Prof. J.S.Sudarsan for guiding and helping us through out our internship and in compiling our paper.

We would also like to express our gratitude to our HOD Dr. Sathyanarayanan for his constant encouragement and support and to SRM University for providing us with the opportunities to show our work.

This study would have remained a dream if we would have worked on it alone. We feel proud to thank the management team of M/s. Dada Silk Mills, specifically Mr. Atik Zuber Kunda, Partner of M/s. Dada Silk Mills for his kind co-operation.

With heartfelt gratitude, we earnestly thank Mr. Ajay Valvi, Sr. Engineer and Mr. Yusuf Fensi, Sr. Manager at M/s. Dada Silk Mills, Surat for providing us with their valuable guidance, patience and encouragement.

We would like to thank Mr. D. M. Thaker –Environment Engineer at Gujarat Pollution Control Board, Gandhinagar for his valuable suggestion.

We would also like to thank technical team members of M/s. En-vision Environmental Services, Surat. We feel extremely happy to thank Mr. Kunhal Shah and Mrs. Shilpa Shah, Partners, En-vision Environmental Services who always encouraged us to learn, gain knowledge and spend quality time in research related work. They explained to us the key concepts of air pollution and its measures taken to control it without which this study would have not been possible.

Ms. Urvi Mistry, Technical Department, M/s. En-vision Environmental Services, Surat deserves special credit for her most co-operative, painstaking attitude and untiring efforts for getting technical reports, editing and documentation.

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