New guy, old project

[lakeweb]

Hi,
I don't know why I had not run across this place before. I've been at this for a couple of years now and had done lots of searches on the subject. I'll insert some project pics below. I started many years ago only knowing I wanted to go some where. Back then, I could buy electric baseboard heaters at thrift stores for a buck a piece. So I loaded up. I've cut the electric heaters out so I could circulate fluid from under our mobile into them. Later I learned about gasifying boilers. My wife would have liked to see me buy a Tarm. But I have to do it myself. I boiled water for the first time a couple of weeks ago. I think I'm at least going to be able to direct heat for this winter. I'm not going to reach for storage yet. Here, I'll let the pics and my first page say the rest.




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I'm working on the supply, blow back system now, but I don't have a pic yet

Best, Dan.

 

[leaddog]

looks like a fun project. When you get done you will know a lot about gasifiers. You might not save any money in the long run but there is a satisfaction on building something your self and making it work and you WILL know how your system works. I've done a lot of experimenting myself and I suppose if I took all the money I've sunk into my projects I would have been better off buying new and let someone else put it in but I wouldn't have had as much fun and sense of accomplishment.
Very interesting primary secondary air set up. Are you going to control with and o2 senser?
leaddog

 

[bigburner]

Dude you remind me of me. It's all about the journey not the destination. built a bunch of my mine also. You have built the ugliest HX I have ever seen, I can tell you from my experience owning large commercial ice makers the heat transfer should be good. It looks like a fire tube boiler, couldn't see any stay bolts, please add them if you are pressurizing.

 

[lakeweb]

Hi leaddog, bigburner,

Thanks! Yes, the plan is to lambda the burn. I'm just guessing the mix for this shop test. I've got a micro programmed to drive the stepper.

The boiler is in the blue sheet metal box so that the gas runs up the fire tubes and back down the outside surface. I was boiling about 7-8 gallons/hour here with an exhaust of 250F, so I'm pleased so far. I'll add swirlers and that may mean I can do 90kbtu/hour with a decent efficiency.

No, I'm not going to have any meaningful pressure. I've come up with about 2psi to move the steam to the condenser. Heating boilers should be run at as low a pressure as possible so I should be safe. I'll have a pop off that blows at some 5-7psi. I pressure tested at ~50psi to make sure I found all the pin holes, and yes, the sides would bulge. The boiler is 1/8" plate.

I got 600' of 3/4" pex last week, (it was a good ebay deal so I got plenty.), and fittings are on the way. It is starting to feel like I'll see this operational for the winter!

Best, Dan.

 

[bigburner]

Why steam, please explain the lay out of your system. are you planning on using a HX to heat water for baseboard or similar. I have a fairly good understanding of latent & specific heat and the advantages of steam but don't understand your approach.

 

[bigburner]

got a few more questions! To "lambda the burn." My guess is that a at least two sensors are required, a stack sensor [O2], air inlet temp, and/or a parameter based on air volume and then some dampening based on response time. What you thinking here. Thanks

 

[lakeweb]

Hi BB,

I know what you mean about using a water loop 'boiler'. And if I were starting from scratch today, that may be the way I'd go. But I had envisioned this boiler supplying my house storage and the shop. Over 200 feet of distance and steam moves by itself in small pipes. Did you see my 'heat storage' page? That is where the steam will really end up. And from there I'll circulate an antifeeze mix though the baseboards. So for now, I'll condense the steam in a small heat exchanger next to the house to heat the home loops. The boiler will still be some 50 feet from the house. As I have to store the boiler water in the house for now, this should work out fine. The boiler feed and blowback will end up in the storage building. Yea, steam may be overkill here, but what fun!

I'm going to start with an automobile O2 sensor and see how that goes. From what I've read, some 5% excess oxygen is optimal at keeping the system clean and efficient. It may be a long time before I know if that is really where I'm at. But if I modulate on the lean side I, would think I'm close enough for now. So all I will go on is the O2 sensor. Unlike an automobile where changes in HP and gas volume are all over the place, this runs fairly steady state. So, I'm not sure why I would have to monitor more than the O2 sensor. All the filtering will be done in the micro. Using an oxy-pulse sensor, here is my heart beat filtered six orders deep with a sharp cutoff at 60hz, (florescent light proof, and I had them on). And it is streaming the data out at 115k baud. The 'fuzz' is the difference between the IR and Vis LEDs, the filter runs on two data streams. This is the same processor I'm using on the boiler, this micro will spend most of its time idle.

I'll start by making it a dumb device as it is out in the wilderness. Have it report thermocouples/thermistors, O2, etc. and take instructions to modulate mix, blower speed.. I'll have it talk to my box on a UART line and work with it from my desk.

Best, Dan.

 

[bigburner]

My boiler was born in 1932, some where in Ohio. It lived as a steam boiler feed by coal for 50 years & was on vacation for 25 years. When I got it we did a hydro, passed, no problems. I considered steam because I have a hill that would make the condensate return by gravity. Brother talked me out of it. Now it's wood fired updraft gasser.[this will be third season] This system is big with a lot of storage, controlling the burn is very interesting to me, or at least knowing what a change makes to "say the stack temp/O2". I haven't used an oscilloscope in thirty years so I am a little rusty on electronic side of things, luckily I can still read. so keep us posted or send me a PM with up dates Thanks

 

[kabbott]

Yes, Please keep us posted. I have an O2 sensor installed on my boiler but only for data at this point. The long term plan
is closed loop control with the Nofossil control system..... might be a while though, to many other "irons" in the fire right now.

 

[lakeweb]

Hi BB,
I will keep posting as I get more of the chunks done. Thanks.

Kabbott,
I followed up on what the NFCF was all about. Very nice that someone went open source with this. The price performance of the TS-7260 look really nice. I've thought of reaching for a pc/104 system in the past but just never went there. It has always been the little micro, (I'm pretty dedicated to the MSP430 series now), or a box. A quarter of a watt when sleepy! Makes it off gridder friendly.

Thanks for the heads up.

Best, Dan.