Novel application: Bag House for Spent Wash Application

Introduction:

Flue gases generated from spent wash incineration is acidic and highly corrosive in nature. Air pollution control equipments used for capturing dust from such flue gases face numerous challenges, which make it difficult for operation. Bag filters are the common choice of air pollution control equipment in such application. Often bag filters face problem such as increased differential pressure (DP), choking of bags, failure of bags, and corrosion in top portion of filter, cages & bags. These problems have to be overcome in order to achieve continuous operation of bag filter. Clair Engineers Pvt. Ltd. (CEPL) has had the opportunity to install numerous installations of bag filters for spent wash applications. All the installations made till date have been running successfully. Bag filters installed by CEPL have been able to overcome the challenges of corrosive flue gas from spent wash application and also achieve a satisfactory operation meeting stringent emission norms.

We have supplied a bag filter for a sugar manufacturer from Uttar Pradesh. CLAIR got an order to design and install a bag filter to capture dust from flue gases generated from burning spent wash with various combinations of supporting fuels in the boiler. The fuels used in the boilerare spent wash & bagasse, spent wash & imported coal, spent wash & Indonesian coal, 100% bagasse, 100% imported coal and 100%Indonesian coal.                                                 

Observations:

• The bag filter designed can accommodate gas flows from 62 to 74.5 m³/sec. The bag filter can handle inlet dust load capacity from 6 to 38 gm/Nm³
• The ash content in the flue gas varies from 1.5 to 39.8%.The flue gas composition varies radically and CEPL’s bag filters are designed to handle these variations comfortably
• The bag filter is able to achieve emissions of ≤ 30 mg/Nm³ when it is fired with spent wash and other fuel combination
• The plant is able to generate 9 MW power from the incineration process which has enabled the plant to be self-sufficient with regards to power consumption. The steam generated by the plant is also being used for process steam requirement of the distillery unit
• The plant was able to operate the boiler continuously for a period of 90 days to which the installed bag filter was also in operation
• There have been no instances where the boiler operation was stopped due to the maintenance or any issues of bag filter
• The guaranteed differential pressure across the bag filter is 180 mm WC
• Currently the bag filters are operated between 130-150 mm WC and have been able to save on the motor power KW
• CEPL bag filters are offered with an outlet emission guarantee of ≤30 mg/ Nm³ as per the requirement of the emission norms

Picture: