Long meandering siloloquy about burning drift wood.
Posted: Tue Jan 03, 2012 4:14 am
In the San Juan islands, where I live, there is a large and continuing supply of drift wood above the high tide line. Several steamers, the Fire Canoe included, have made use of this resource for travel beyond the local area. There are, of course, several drawbacks. Before you guys start tuning up about the usual things, here is a short list that I know of.
Burning salt produces toxic byproducts. Yes, it is a problem with big pulp mills but I have my doubts about this being a problem with a boiler. Right now, I am burning fir in my living room stove that has never been floating about the bay and the flames are very yellow. As far as I know (not far) this color comes from sodium which almost has to in compound with chlorine. My ancestors have been burning wood for a gazillion years now an mostly dieing from alcohol and bad marriages rather than stove fumes. Maybe a problem but I'll live with it.
Salt corroding the boiler. Hm. If I swamp out the flues in my VFT with a flue brush fairly regularly, it shouldn't be a problem. The corrosion would happen when the boiler was laying around between uses with moisture from the air combining with the salt to cause corrosion. I dunno how you clean out a water tube boiler. I guess Tommy Thompson didn't clean his out and had to replace his boiler at least once.
Wet wood. Depends. Most of the wood has been out of the water for a long time. It has been in the rain though. So the outer five percent of it is wet. This is a significant problem. It will take a bit of time after each firing to evaporate the water. Significant loss of efficiency.
But the stuff is free and stored along my way so I can live with those problems if the boat will continue to move along.
If my power plant is running O.K. with dry wood, what can I do to burn wetter wood? The answer usually bandied about is to use some increased draft. But how to do it. All of the stories I have head about cramming air in at the bottom end up with more stories about a face full of soot and singed eyebrows. On a locomotive or donkey boiler, the only types I have run much, we use induced draft with a steam nozzle at the stack end of the boiler. The nozzle uses either engine exhaust or boiler steam direct. I don't want to use either of these methods. I boat in salt water and hauling along a bunch of makeup water is out.
There remains a fan in the stack or some way of blowing air up the stack. I just can't see how to do the fan thing without a really Rube Goldberg setup of some sort. A flex cable or electric fan or an auxiliary engine running all the time. Have I missed a way to do this?
So I am down to blowing air up the stack. Steve Harcourt has a turbocharger off of Wes's Buick rigged so that the engine exhaust spins it (at a tiny fraction of automotive speeds!) and the compressor side is fed up the stack. He reports that it will suck flames out the stack! But it reportedly makes a racket from the air intake. Worth looking into though.
My brainstorm, the one that has me bothering all of you, is to use an automotive smog pump belted off of the main engine or an auxiliary engine with the output fed up the stack. I cannot find ANY specs on these pumps. I know that they run forever with no maintenance. They produce enough pressure to overcome the average pressure in a car exhaust, perhaps a few psi. They blow though a one inch rubber hose and my memory is that the 'blast' is some what less than a shop vac output when reversed but more than I can blow myself (No wise cracks).
I dunno if I will have to step it up too much for practicality. Might end up with way too big of a pulley on the engine.
Have any of you tried this? I'm going to try spinning one with my drill press motor this week. Wish me luck.
Mike
Burning salt produces toxic byproducts. Yes, it is a problem with big pulp mills but I have my doubts about this being a problem with a boiler. Right now, I am burning fir in my living room stove that has never been floating about the bay and the flames are very yellow. As far as I know (not far) this color comes from sodium which almost has to in compound with chlorine. My ancestors have been burning wood for a gazillion years now an mostly dieing from alcohol and bad marriages rather than stove fumes. Maybe a problem but I'll live with it.
Salt corroding the boiler. Hm. If I swamp out the flues in my VFT with a flue brush fairly regularly, it shouldn't be a problem. The corrosion would happen when the boiler was laying around between uses with moisture from the air combining with the salt to cause corrosion. I dunno how you clean out a water tube boiler. I guess Tommy Thompson didn't clean his out and had to replace his boiler at least once.
Wet wood. Depends. Most of the wood has been out of the water for a long time. It has been in the rain though. So the outer five percent of it is wet. This is a significant problem. It will take a bit of time after each firing to evaporate the water. Significant loss of efficiency.
But the stuff is free and stored along my way so I can live with those problems if the boat will continue to move along.
If my power plant is running O.K. with dry wood, what can I do to burn wetter wood? The answer usually bandied about is to use some increased draft. But how to do it. All of the stories I have head about cramming air in at the bottom end up with more stories about a face full of soot and singed eyebrows. On a locomotive or donkey boiler, the only types I have run much, we use induced draft with a steam nozzle at the stack end of the boiler. The nozzle uses either engine exhaust or boiler steam direct. I don't want to use either of these methods. I boat in salt water and hauling along a bunch of makeup water is out.
There remains a fan in the stack or some way of blowing air up the stack. I just can't see how to do the fan thing without a really Rube Goldberg setup of some sort. A flex cable or electric fan or an auxiliary engine running all the time. Have I missed a way to do this?
So I am down to blowing air up the stack. Steve Harcourt has a turbocharger off of Wes's Buick rigged so that the engine exhaust spins it (at a tiny fraction of automotive speeds!) and the compressor side is fed up the stack. He reports that it will suck flames out the stack! But it reportedly makes a racket from the air intake. Worth looking into though.
My brainstorm, the one that has me bothering all of you, is to use an automotive smog pump belted off of the main engine or an auxiliary engine with the output fed up the stack. I cannot find ANY specs on these pumps. I know that they run forever with no maintenance. They produce enough pressure to overcome the average pressure in a car exhaust, perhaps a few psi. They blow though a one inch rubber hose and my memory is that the 'blast' is some what less than a shop vac output when reversed but more than I can blow myself (No wise cracks).
I dunno if I will have to step it up too much for practicality. Might end up with way too big of a pulley on the engine.
Have any of you tried this? I'm going to try spinning one with my drill press motor this week. Wish me luck.
Mike