ACC Limited is part of the Swiss-based Holcim Group and is India´s foremost manufacturer of cement and concrete. It takes a lead in environmental protection at all its plants; situated close to the Himalayas, the ACC Gagal plant is committed to responsible, sustainable development that respects the environment.
The plant has two lines producing 4,300 tpd and 5,000 tpd respectively. FLSmidth has had a close relationship with ACC for many years and is its preferred supplier. The Gagal plant wanted to comply with current environmental regulations and also reduce emissions as much as possible. The plant wanted to capture the maximum amount of fly ash and minimise the amount of dust going into the stack.
Being a brownfield project, there was a space constraint that needed to be considered. There was no space for placing the bag filter near to the stack except on the road, which was in use. Therefore, FLSmidth designed the bag filter to be placed at an elevation to allow continued use of the existing road. Civil works were also designed to allow access below the filter for heavy vehicles and other transportation. To accommodate the space constraint, the filter was designed with 10-metre long filter bags.
Erecting heavy equipment was a big challenge as existing conveyors are located on both sides of the filter. The teams worked well together and careful planning contributed to a quick and smooth installation.
The project was completed with a very short delivery time: just 10 months from start to finish. All construction took place while the plant was in operation and the installation was connected during a regular planned maintenance shutdown.
All the equipment was stabilised within one day of operation and a very satisfactory performance test was completed. The emissions achieved are 1.75 mg/Nm3, which is well below the guaranteed figure (10 mg/Nm3) and the local environmental regulations (30 mg/Nm3).
The pressure drop over the entire filter is as low as 9.7 mbar, which indicates a very efficient cleaning system as well as an advanced filter media. The power consumption of the ID fan is also lower than the guaranteed figure at 600 kW.
- Bucket elevator
- ID Fan and HT motors
The scope included a duct and duct support from the cyclone outlet to the inlet of the stack, and dust transport equipment, such as a drag chain, bucket elevator, compressor and ID fan.
The site is located in an extremely hilly area so one of the challenges was to transport equipment to the site, and extreme rain and cold added to these transport difficulties. It was also important to motivate labourers to stay on the site in the extremely cold conditions.
Excavating close to the existing plant foundation was a very tough task and some unexpected pipelines were discovered that had to be re-routed. The civil works was still successfully completed in spite of rain during most of the project...
The Gagal plant now has:
Reduced power consumption due to reduced pressure drop across the filter (and the whole system) and reduced compressed air consumption;
Reduced environmental impact due to low emissions in the stack
User-friendly SmartPulse Controller®: for bag house operation
FabriClean® filter with online maintenance facility
1,728 10-metre long bags (woven glass with PTFE membrane)
User-friendly SmartPulse Controller®:: SPC 1691.
(This article has been authored by Nikhil Kulkarni, Head Sales & Marketing -AIRTECH).