Back in the good old days of cheap gasoline, automobiles were little more than metal-wrapped living rooms on wheels. Big, garish and severely polluting. Along comes the Corning glass people. Playing with high temperature ceramics and some platinum during the 60's, the good chemists add a new word to the dictionary - catalytic converter.
Fast forward about ten years to the mid 70's. One of the chemical engineers is having trouble keeping his chimney clean. He figures that a modification of the automobile catalyst might be a help with his wood-consuming problem. Turns out that hundreds of hours and a million bucks or so later, the woodstove catalyst is a reality. Sort of.
The first major company to use the new technology was such a questionable manufacturer that the concept of clean-burning nearly died with the stove. Our government, having had little success with huge polluters such as Big Oil, Chemical Manufacturing, Coal-fired Electric Industries and the like, decided that the tiny wood heating industry could be made an example of. It wasn't long before about 400 manufacturers of woodstoves and ten thousand employees felt the wrath of bureaucracy-gone-berserk.
On the other hand, holders of large amounts of Corning stock noticed a couple of extra quid in their Christmas bonus stockings. The catalytic converter for wood heat was here to stay. Ultimately, it may have been one of the better things to happen. Keep in mind that the catalyst is only one of the two common forms of technology to help wood heat be less polluting. Each type of clean air engineering has its pros and cons. Catalytic converters start out more efficient (somewhat) than the non-catalytic type stoves, but gradually deteriorate with time.
When it's Time to Clean the Catalyst
If caught early enough, a catalyst can be cleaned using what Corning calls a "Major Cleaning Procedure." As a faithful reader of this column, you are about to learn how to clean a catalyst safely. This relatively easy procedure can save you, or at least postpone, the cost of a new catalytic converter.
After two year's worth of Vermont winters, a catalyst will have lost some of its effectiveness. Unless something is obviously wrong, such as a four-inch gaping hole in the middle, the catalyst is ready for a major cleaning. If the catalyst suddenly failed after a blast of 150 pound-per-square-inch dusting off, there is no need to clean it. A high pressure air hose will blow off the catalyst metal, which is usually Palladium, with the fly ash. An interesting point is that now the ash is more valuable than the catalyst. You will have to buy a new catalytic converter. Don't even think about operating the stove without a catalyst, it certainly won't work well. There is also that pesky $10,000 Federal fine that we in Vermont would ignore. Apparently ratting out your next door neighbor in some western states for the finder's fee is big business. It's at least as lucrative as stealing evergreen brush off your neighbor's back lot and selling it to wreath makers.
The following information has been gleaned from conversations with Nancy Fish of Corning, Inc. and actual testing by yours truly. First, the disclaimers.
If you don't think you can do this procedure, you are probably correct. You must be able to properly remove, handle and reinstall the catalyst. Otherwise the catalyst, or the stove, might suffer needlessly.
This procedure is for the combustor only, and it does not reduce or eliminate the need for regular chimney inspection and cleaning.
Burn natural wood only! No garbage, artificial logs, paper, gift wrappings, coal, lighter fluids, treated or painted wood, driftwood, or powdered chemical cleaners. Catalytic combustors can operate at temperatures over 1800 degrees F. At this temperature, the catalyst cell can crack. Common temperatures are within a safe range between 1400 degrees F and 1600 degrees F, but staying below 1400 degrees F and above
700 degrees F are best.
Corning recommends that you not drop your catalyst, run water through it, remove the stainless band (if one surrounds it), scrape the inside walls of the cell or use compressed air to clean it. Many of these admonitions are reasonably obvious.
Any accumulated creosote that may be on the catalyst must be burned off. The catalyst will appear black or dark brown, if creosoted. Corning also suggests that you not remove the cell until both it and the stove cool down. Does the word litigious mean anything to you? The catalyst will appear light gray or beige when it is free of creosote. We are now ready to clean the catalyst in a solution of vinegar and water.
Minimal Equipment Needed
You will need a non-reactive pot big enough to easily hold the catalyst. Non-reactive, for those who haven't made pickles since the second year of the first Coolidge administration, means stainless steel or enamel coated.
You are advised not to use this pot for cooking purposes. You won't want to. Trust me. The larger mass merchants routinely offer stainless steel eight-quart stock pots for under ten dollars, on sale. Most serious cooks wouldn't use these pots in the first place, so they are perfect for catalyst simmering. You can reuse the pot to simmer a catalyst in the future.
Distilled, or de-ionized, water is needed to cover the catalyst by at least an inch three separate times. At least two gallons, but even three may be appropriate. Up to one gallon of white vinegar will be needed in the first simmering. Any left over vinegar will be handy if you have the urge to try a batch of pickles in the near future.
Without getting overly redundant, you will need those tools necessary to remove and reinstall the catalyst. Be sure to order any gaskets to seal the cleaned catalyst, if needed. A length of 14-16 gauge stranded wire is handy to make a bail, or grab handle, to lift the catalyst out of the hot solution. Thread the wire through two cells of the combustor very carefully. Do not scrape the walls of the cell or break them. The wire will lift the catalyst off the bottom of the pan, but I like to put two dowels across the bottom to raise the cell.
The "Major Cleaning Procedure"
Mix a 50/50 solution of vinegar and distilled water. Bring up to a boil, then reduce the heat to just below boiling. Lower the catalyst into the solution for 30 minutes. Be sure to keep the catalyst covered at all times in the solution. While simmering the combustor, bring enough water to a boil to fully cover the catalyst. After 30 minutes, remove the combustor, placing it on several folded paper towels.
Dump out the cleaning solution. Rinse the pot. Pour the boiling rinse water into the vat and gently lower the catalyst. Keep the rinse water at just below boiling. Simmer the catalyst for 15 minutes. During this procedure, bring another batch of distilled water to a boil. Repeat the rinse cycle.
Remove the cell. Shake of the excess water, allow to dry 24 hours. (If you must use the catalyst right off, place it in a 300 degrees F oven for an hour. Cool down and reinstall.) The catalyst will not appear substantially changed to the human eye.
This procedure has been shown to effectively restore a non-worn out and non-damaged catalytic combustor. It may be possible to repeat the cleaning procedure in a year, depending on the age and use of the catalyst.
Even if you have to buy an inexpensive pot, the cost for this operation averages about $15. Very few combustors cost less than $100, with most priced at $125-$175. Need a calculator?
Daryle Thomas, proprietor of the Hearth and Cricket Stove Shop, writes warmly about heat from East Wallingford, Vt.
If
you lead a good life, eat all your vegetables and say all your
prayers, when you die you'll go to Vermont.
Oh No! My Woodstove Has a Catalyst in It!!
