Bio-mass : will that be filtering, pyrolysis or gasification?

posted by Paul Boldt
in energy

“Pratt & Whitney Rocketdyne and Zero Emission Energy Plants, Inc. Sign Gasification Licensing Agreement”,

“Vegawatt plugs in grease-fired restaurant generator”, and

“Pratt & Whitney Rocketdyne and AERI Collaborate to Develop Gasification Technology”;

are but three headlines that have appeared over the last several months regarding systems and/ or methods for processing a carbon-containing feedstock into some type of fuel. There are a myriad of techniques for the above processing, each having a different set of pressure, atmosphere and reaction conditions. The particular combination of reaction conditions being dictated by at least the nature of the feedstock and the desired end product.

With consideration to the second headline, the Vegawatt system is designed to use waste vegetable oil to generate on-site electricity. It is indicated on the Vegawatt website that a four-stage cleaning process is used to process the waste cooking oil for use as a fuel. In this case the original hydrocarbon chain is most likely still intact. Such a process is quite different from that of the Pratt & Whitney Rocketdyne (PWR) technology.

A flavour for the PWR gasification technology emerges from visible patent documents. In general PWR appears to have developed a high temperature, high pressure system, similar to a so-called entrained flow gasifier. Published US patent application 2008/0141913 describes a dump cooled gasifier. In particular it describes structures around a slag-based regenerative liner. Published US patent application 2008/0060914 and issued US patent 7,303,597 describe feed systems for use with a gasification system. A common theme emerging from these and other PWR documents is the development of technology around providing for a continuous gasification process.

While the above two approaches appear quite different on the surface there is a least one common thread, the use of what would have been once considered waste as a source of energy. Both processes also discuss the implementation of “waste” heat to further improve the overall energy captured from the fuel.