Pyrolysis Plant (Gasification)

We propose to build a pyrolysis waste to energy plant at Richborough to process 75,000 tonnes of mixed waste per annum. This will produce 7.5MW of renewable electricity and 8MW of renewable heat for the local community. The pyrolysis technology does not allow oxygen into the conversion process, so no combustion, and no incineration takes place. It converts mixed waste into a clean synthetic gas that can be used as a substitute for natural gas in energy production.

The process:

• Fuel Preparation - receiving and storing waste material, shredding, drying and supplying prepared fuel to the converter. The waste materials are carbon based i.e. any waste that has an intrinsic energy value such as organic waste and plastics etc.
• Pre-treated waste enters the pyrolysis unit very slowly so that it converts into a gas almost instantaneously – a bit like a water droplet hitting a hot plate on a hob. This process is called sublimation and it is this gas that is high in energy value. If waste was burned the gas produced would be of a very poor quality, so we make sure no incineration takes place.
• Gas Conversion - inside the chamber, waste is rapidly heated to over 800oC in the absence of oxygen. The technology ‘thermally cracks’ the waste and does not burn it because the resulting synthetic gas is much cleaner and more energy rich that way.
• Everything has a use…any material that does not convert is collected as a char at the base of the converter, which can be used as an aggregate (e.g. in road building).
• Renewable energy production - using the syngas to power an engine in order to generate renewable electricity for the National Grid.

The GEM process is a closed loop system with only one point of emission at the back end of the process after the engine. Emissions pass through a catalytic converter where they are cleaned. The technology operates within strict Environment Agency emission limits.

The GEM process has been recognised by Ofgem as eligible to receive ‘double ROCs’ for the renewable energy it produces. A ROC (Renewable Obligation Certificate) stipulates that the technology is considered renewable by the UK government. A double ROC status is the highest an advanced conversion technology can receive. By way of comparison incineration is not recognised under the ROC scheme.