Materials recycling apparatus
Materials recycling processes that include a combustion stage can operate very efficiently, but can produce exhaust gases that are high in carbon monoxide and the like. We describe a treatment unit which comprises a chamber for receiving the material, a heat source for (preferably) heat-treating the material and for initiating combustion, and a gas outlet from the chamber, which allows the gas that is exhausted via the outlet to be supplied to the air inlet of an associated boiler unit, with the air inlet and a separate fuel inlet feeding a burner for combusting fuel from the fuel inlet in air from the air inlet in order to heat a transfer fluid. In this way, the unburnt elements of the gas expelled from the chamber are included in the combustion process of the boiler unit and fully combusted. A corresponding method is also disclosed.
1 . A method of treating material, comprising the steps of:
heat-treating the material anaerobically to yield pyrolysis products namely syngas and oils;
extracting the pyrolysis products to leave behind a char residue;
admitting oxygen thereby to combust the char residue in the absence of the pyrolysis products;
exhausting at least the gaseous combustion products from the combustion of the char residue to a boiler unit, optionally admixing these combustion products with air;
in the boiler unit, combusting a fuel in combination with the gaseous combustion products, to heat a transfer fluid.
2 . A method according to claim 1 in which the gaseous combustion products are fed to the boiler unit via a heat exchanger.
3 . A method according to claim 1 in which the gaseous combustion products are fed to the boiler unit via a scrubber to remove entrained particulates.
4 . A method according to claim 1 in which the transfer fluid is water-based.