Coalgun- Puff backs & Explosions

Re: Coalgun- Puff backs & Explosions

PostBy: Yanche On: Thu Jan 02, 2014 9:43 pm

Kennebago wrote: snip ..
As someone mentioned earlier, to control a variable you want to measure it directly and the good news is in this day and age you can directly measure almost anything and with modern PLC controllers you can control it in a closed loop fashion. This does NOT have to mean a lot more cost - it just means taking an approach that is commensurate with the problem at hand. Many problems that were not solvable in the 40's (Compare that carburated DeSoto with a 2014 FI Chevy)are easily solved today. Seems to me there is an opportunity for someone (perhaps AHS) to re-engineer a boiler system, to make it efficient, automatic, cost effective and above all safe.

Things like combustion mixtures can be measured and controlled, the need for air can be anticipated and injected so its there when its needed. My guess is that one of the biggest problems is that the size of the market won't support the R&D necessary to put such a unit on the market -- Ohhh - if only I was a bit younger.

snip ...


Kennebago ... Welcome to the forum. I'm particularly interested in your comment about measuring combustion mixtures. What types of sensors are you referring to? Brand names and/or part numbers would be helpful. I've considered making an instrument to do so but was thwarted in not being able to find a suitable combustion sensor. I found some, but they cost more that the boiler (-: As is see it there are two control loops required, one for burning height in the antratube and a second for combustion mixture control. Combustion height could be sensed with a linear array of thermocouples or perhaps as few as two and a software algorithm. The microcontroller specs would be really minimal since there is no need for high speed computations.
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: Coalgun- Puff backs & Explosions

PostBy: McGiever On: Fri Jan 03, 2014 12:33 am

NWBuilder wrote:It's wide open now. Always has been.


What is your Ashing Temp Setting?
Wondering what the manometer is saying...?

Might try to turn it down just a smidgen and see how it likes that.

The way your boiler would be burning on a day like we've been having and then to have double puffbacks while it is still running is perplexing. :?
I suspect it is burning a very thick fire, and generally the puffback comes when an excess of fresh coal w/ it's volatiles are not being consumed as steadily as they are produced. (condensed version...you're ashing just a little too fast now w/ the new thicker fire that has developed underneath)
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Hot Air Coal Stoker Stove: HARMAN MAGNUM
Hand Fed Coal Stove: RADIANT HOME AIR BLAST
Baseburners & Antiques: OUR GLENWOOD 111 BASEBURNER "1908"
Coal Size/Type: PEA / ANTHRACITE, NUT-STOVE / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: Coalgun- Puff backs & Explosions

PostBy: blrman07 On: Fri Jan 03, 2014 5:34 am

lsayre wrote:
NWBuilder wrote:I have been running this coal which is oiled for 1.5 years now first time this has happened. Maybe they don't and this batch had a little more oil in it? Don't know.


Or perhaps your current batch of coal has a higher level of volatiles plus the same amount of oil? Coal Guns don't take well to volatiles, and adding oil is similar to adding volatiles. The two together make bad juju.


I couldn't sleep this morning so I got up around 3:15 or so, wide awake for no apparent reason so I decided to peruse the board and what to my wondering eyes should appear,,,,,lsayre's post on oiled coal possibly contributing to the puff back scenario. When I saw this I laughed scaring the cat sleeping by the coal stove.

It's bad juju!!! :shock: How long does juju last before it goes bad? Maybe that's my problem. My juju has not turned yet but it's probably getting to the point like with milk where you sniff it first, sniff it again, take a small sip, then offer to your wife asking " I think the milk is going bad. Taste it and let me know." She puts one hand on her hip and asks " Why are you offering me spoiled milk?" :mad:

Now I know why stuff is happening to me.

My juju is turning bad. Dang and I was being so careful with it. Bad Juju......that's it. Thanks for the laugh. Now to get the cat to go back to sleep......then me.

Rev. Larry
blrman07
 
Hand Fed Coal Boiler: Bucket a Day
Hot Air Coal Stoker Furnace: Leisure Line Econo 1 stove
Coal Size/Type: Rice in the LL and anything that will fit in the Bucket a Day. It's not fussy.

Re: Coalgun- Puff backs & Explosions

PostBy: greenftechn On: Fri Jan 03, 2014 9:50 am

(condensed version...you're ashing just a little too fast now w/ the new thicker fire that has developed underneath)


This.

Have a look and appraise the position of the fire. When the fan is running, flames at the top of the coal pot should be consuming ALL the volatiles being produced. Lowering ash temp raises the fire. That may be just what you want.
greenftechn
 
Stove/Furnace Make: Alternate Heating Systems
Stove/Furnace Model: E100

Re: Coalgun- Puff backs & Explosions

PostBy: NWBuilder On: Fri Jan 03, 2014 3:19 pm

McGiever wrote:
NWBuilder wrote:It's wide open now. Always has been.


What is your Ashing Temp Setting?
Wondering what the manometer is saying...?

Might try to turn it down just a smidgen and see how it likes that.

The way your boiler would be burning on a day like we've been having and then to have double puffbacks while it is still running is perplexing. :?
I suspect it is burning a very thick fire, and generally the puffback comes when an excess of fresh coal w/ it's volatiles are not being consumed as steadily as they are produced. (condensed version...you're ashing just a little too fast now w/ the new thicker fire that has developed underneath)


My ashing temp is at 108 with 5* variance and my manometer is running between 02 and 05
NWBuilder
 
Stoker Coal Boiler: Ahs 130
Coal Size/Type: Burning Pea anthracite

Re: Coalgun- Puff backs & Explosions

PostBy: NWBuilder On: Fri Jan 03, 2014 3:22 pm

greenftechn wrote:
(condensed version...you're ashing just a little too fast now w/ the new thicker fire that has developed underneath)


This.

Have a look and appraise the position of the fire. When the fan is running, flames at the top of the coal pot should be consuming ALL the volatiles being produced. Lowering ash temp raises the fire. That may be just what you want.


Should I go lower then 108 with my ashing temp? I will check the fire when the blower is running. I checked it at idle and you can see some blue flames towards the back by the exhaust vent but otherwise just looks like nice black coal.
NWBuilder
 
Stoker Coal Boiler: Ahs 130
Coal Size/Type: Burning Pea anthracite

Re: Coalgun- Puff backs & Explosions

PostBy: lsayre On: Fri Jan 03, 2014 3:38 pm

NWbuilder, perhaps you are a candidate for the new timer regulation of ashing modification that AHS is offering for the direct drive ashing models?

Does you system ash via the older chain drive method, or via the newer (and much faster acting) direct drive?
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Anthracite Pea
Other Heating: Resistance Boiler (if I ever get it fixed)

Re: Coalgun- Puff backs & Explosions

PostBy: NWBuilder On: Fri Jan 03, 2014 3:59 pm

lsayre wrote:NWbuilder, perhaps you are a candidate for the new timer regulation of ashing modification that AHS is offering for the direct drive ashing models?

Does you system ash via the older chain drive method, or via the newer (and much faster acting) direct drive?

I have the direct drive style. Maybe that is the way to go
NWBuilder
 
Stoker Coal Boiler: Ahs 130
Coal Size/Type: Burning Pea anthracite

Re: Coalgun- Puff backs & Explosions

PostBy: McGiever On: Fri Jan 03, 2014 4:32 pm

:verycool:

NWBuilder wrote:
lsayre wrote:NWbuilder, perhaps you are a candidate for the new timer regulation of ashing modification that AHS is offering for the direct drive ashing models?

Does you system ash via the older chain drive method, or via the newer (and much faster acting) direct drive?

I have the direct drive style. Maybe that is the way to go
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Hot Air Coal Stoker Stove: HARMAN MAGNUM
Hand Fed Coal Stove: RADIANT HOME AIR BLAST
Baseburners & Antiques: OUR GLENWOOD 111 BASEBURNER "1908"
Coal Size/Type: PEA / ANTHRACITE, NUT-STOVE / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: Coalgun- Puff backs & Explosions

PostBy: Kennebago On: Sat Jan 04, 2014 4:50 pm

Yanche wrote:What types of sensors are you referring to? Brand names and/or part numbers would be helpful. I've considered making an instrument to do so but was thwarted in not being able to find a suitable combustion sensor. I found some, but they cost more that the boiler (-: As is see it there are two control loops required, one for burning height in the antratube and a second for combustion mixture control. Combustion height could be sensed with a linear array of thermocouples or perhaps as few as two and a software algorithm. The microcontroller specs would be really minimal since there is no need for high speed computations.


Your point is, of course, on the mark. Typical combustion sensors are expensive and the problem gets worse when looking for something that will withstand the environment of a combustion chamber burning coal. I have nothing suitable to recommend at the moment but for what it's worth I am looking for a solution. It is important to find something that is made in high volume for an already existing application and piggyback on that. The sensors are just a part of the problem since the controller that receives the info and decides what to do about it can also be expensive. I would be interested if you have any inputs on a tolerable cost range. Our friends across the pond have done a lot of work on improving boiler efficiencies but the approach used in things like the ATMOS system has got to be $$$$$. And at that it gets at the problem by only firing the boiler almost flat out - and then turning it off.

I saw your earlier note and comments on the thermocouple approach. I don't know enough about the configuration of the system under discussion to know if measuring the temperature at various locations on the tube and using the results to control the process will work or not - but what you proposed certainly made sense. I have the uneasiness that comes with not measuring the primary variable but it appears from what you and others have written that measuring and controlling the temp in the tube may be a good alternative. Thermocouples and attendant gadgetry to effect control are certainly much less expensive.

I think the biggest issue would be insuring that the TC was responsive enough based on surrounding thermal mass and that it would could be protected well enough (or be easy to replace) that it would be viable. Type J and K have some tradeoffs in terms of temp and atmosphere capability and certainly would have to be sheathed to enable them to function. Lots of options but if you are going over a measured temp of about 750 C, then it almost has to be type K which has a problem in both reducing or sulfur containing atmospheres. Sheath material would probably need to be something like Inconel 800 or 446 stainless. Some testing along these lines combined with some inventiveness as to TC placement could, I think, lead to a satisfactory set-up.

One last comment - I saw some posts questioning whether the TC's installed were type K or type J - One quick way is that type J's are red and white with red being negative and Type K's are red and yellow with red being negative - probably old news but thought I would mention it
Kennebago
 
Stoker Coal Boiler: Coming Spring 2014
Baseburners & Antiques: Glenwood Oak / Home Grand Restoration Projects
Other Heating: Arrgghh "Oil Boiler"

Re: Coalgun- Puff backs & Explosions

PostBy: dchartt On: Sun Jan 19, 2014 10:04 am

You guys who have had the timer update mailed to you....did they deliver that on horse and buggy?
dchartt
 
Stoker Coal Boiler: AHS 130
Hand Fed Coal Stove: Glacier Bay

Re: Coalgun- Puff backs & Explosions

PostBy: lsayre On: Sun Jan 19, 2014 10:20 am

Quite often I find that no news is actually good news.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Anthracite Pea
Other Heating: Resistance Boiler (if I ever get it fixed)

Re: Coalgun- Puff backs & Explosions

PostBy: dchartt On: Sun Jan 19, 2014 7:47 pm

No offense there but im not looking to hear some news...im looking for the ahs rep to come out of hiding and tell me why my update kit is a month in the making
dchartt
 
Stoker Coal Boiler: AHS 130
Hand Fed Coal Stove: Glacier Bay

Re: Coalgun- Puff backs & Explosions

PostBy: macdabs On: Mon Jan 20, 2014 5:43 am

I hope it arrives soon. I can say I have not had any issues since the delay grate timer install.
Mac
macdabs
 
Stoker Coal Boiler: AHS 260
Coal Size/Type: Pea
Other Heating: Pellet,oil
Stove/Furnace Make: AHS
Stove/Furnace Model: S260

Re: Coalgun- Puff backs & Explosions

PostBy: greenftechn On: Mon Jan 20, 2014 9:02 am

No offense there but im not looking to hear some news...im looking for the ahs rep to come out of hiding and tell me why my update kit is a month in the making


I was completely unaware you were waiting! Darren Bricker is handling these. His email is darren@woodgun.com Mine shows below.

Emailing or calling will get more prompt action, even when we drop the ball. That said, I'll put in the order, and follow up with Darren.
greenftechn
 
Stove/Furnace Make: Alternate Heating Systems
Stove/Furnace Model: E100