Biomass Energy: Incremental Improvements Lead to Sustainable Fossil Replacement

Cellulosic electricity is accomplished in three stages:
1. Pre process the biomass for size and moisture content
2. Gasify the biomass in an oxygen-free atmosphere
3. Use the clean syn-gas to drive a heat engine, generating electricity.

This case history comes from Stoke-on-Trent, UK. A new 4.5 MWe cellulosic electricity plant is scheduled to come on line sometime this summer. But the engineers were having trouble with ash removal, an important adjunct to the gasification step. They were unable to devise a way of removing the ash, while maintaining an oxygen-free gasification environment.

Maintaining an oxygen-free gasifier is essential.

BioMass Engineering had tried using traditional screw feeders and airlock hoppers to remove and store the ash, however, these allowed ingress of oxygen into the process.

The company contacted Ajax Equipment to assist in overcoming the problem.

Ajax devised a plug screw feeder solution to remove the ash from the gasifier and filter.

The screw densifies the ash as it leaves the screw to create an impenetrable barrier.

"Adopting a plug screw feeder allows BioMass to run the process continuously, the ash being removed without oxygen entering the system," said Eddie McGee, technical director, Ajax Equipment.

Jim Campion, managing director, BioMass Engineering, commented, "The way Ajax Equipment approached the problem, and worked with us to find the right solution for removing the ash, has allowed us to improve the overall process reliability".

This Stoke-on-Trent renewable energy plant is set to come into operation mid 2008. __Source

For most "gee-whiz future-addicts" such a mundane industrial story only makes them yawn. But it is such incremental innovations that lead to long-term profitability and adaptation of new methods of energy production and manufacture.