Friday, April 13, 2007

Ottawa waste pilot project: greens don’t know from plasma
Some environmentalists, including the Pembina Institute and Sierra Legal, are opposed to Ottawa’s new high-tech waste disposal pilot project on the grounds that incineration is as dirty as coal combustion.

Right off the bat, they’re wrong. The technology underpinning the Ottawa project is not incineration. It is thermal plasma gasification/vitrification. Pembina and Sierra have been loudly advising the government about how it should meet Kyoto targets. Their position on the Ottawa project makes you wonder how far off the mark their Kyoto advice is. (Hint: it’s pretty far.)

A thermal plasma furnace does use heat to dispose of waste, but the heat is far more intense than what is involved in conventional incineration—so intense that it turns the matter to which it is subjected into gas and glass.


The gaseous byproduct of thermal plasma treatment, which in the case of carbon feedstocks is predominantly a mixture of hydrogen and carbon monoxide, can, theoretically, be further processed or burned in a combined-cycle generator. The emission intensity of this combustion is, again in the case of gasified carbon feedstocks, similar to that of natural gas–fired combustion.

But bear in mind that the Ottawa pilot project won’t necessarily be dealing with predominantly carbon-based feedstock. Municipal waste is heterogeneous. This means the process gas will vary in composition, making it difficult to generalize about its performance as combustion fuel in a CC generator.

Nevertheless, supporters of the Ottawa plasma project tout it as a waste-to-power project. This is an unnecessary claim. Even if it did work, the system would dispatch such a minuscule amount of power to the grid that it wouldn’t even warrant a mention on the IESO’s monthly generator reports.

Rather, the project’s proponents will make their main money from the tipping fee—i.e., what they charge Ottawa to dispose of the waste. If the fee is comparable to what Ottawa currently pays to simply landfill an equivalent amount of waste, and if the proponents can make a profit on that amount, then it’s a good deal.

Instead of chasing the waste-to-power red herring, it may prove more economical to separate the process gas into its constituents and sell them to an industrial gas company. After all, the major players in this field—Praxair and Air Products, especially—have over the past few years been on a patent-filing binge to protect processes that do just that.

Has this led anywhere? In 2003, Praxair teamed up with a plasma furnace manufacturer to test the viability of purifying gas from municipal waste. So far the company has been coy about the results. This suggests that the results have been less than impressive, and that the main value of plasma gasification is the clean disposal of waste.

But regardless of the useful value of the gas, the mainstream greens’ loud opposition to the Ottawa project proves they need to do more homework.

1 Comments:

Blogger Randal Leavitt said...

The Ottawa plasma torch project is a turning point, similar to the invention of the electric stove. It can also be used to process sewage. Cities don't need landfills or sewage treatment ponds any more. A small nuclear reactor and a small plasma torch disposal system should be placed in every neighbourhood. We could live in cities without huge electricity transmission lines. I attended the Plasco public meeting on April 11. It was really exciting to witness a technical revolution happening. The system should be running by June.

1:13 AM  

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