TuftedTurtle

Direct Fire Heat Up Problem

21 posts in this topic

Good Afternoon Everyone,

Our distillery got permited in mid February, we distilled in earlier March and realized that we were very inefficient.  Our heat up time was 3 hours and overall run time was 7-8 hours.  Production was paused and we sought the advice of Ward Burner and made a lot of changes.  Now our heat up time is 4-5 hours.  We are very perplex as to what the issue is and would love some advice or ideas.  Below are the details:

 

The still is housed in a 12x6 foot metal shed.

 

Initial Set Up:

X11 Burner placed at about 11 inches from a copper plate between the still and the burner.

The burner was connected to a 100 pound propane tank via 1/4 inch flexible connection.  This is not ideal, but we are working on moving propane tanks and trenching the property.

Our Regulator is Fisher LOC870 

    Type: R632A-JFF

Bricks are stacked up to past the Manway.  There are spaces in back to vent gas and spaces in the bottom of the stack to let air in.  The flames didn't look great.

 

Our Modifications:

Removed the copper plate between the still and the burner.

Had a combustion chamber built.  The chamber is about 36 Inches in diameter with a bottom and a hole cutout for the burner to project flames into.  We have it lined with ceramic wool for insulation.

I've tried the burner at different heights from the bottom of the still.  11.75 inches, 11 inches and just under 10 inches from the bottom.

The vent is an non-insulated 8 inch stove pipe and has no vent cover on top.

We have changed out the 1/4 inch flexible connector for a 3/4th inch.

The flames looked pretty good.  In insulation seems to be working as it is much cooler in the front and only hot around the stove pipe.

 

We aren't sure what the problem is.  I know we need to get hooked up to a bigger propane tank, but that doesn't explain the efficiency getting worse.  The problem is perplexing and we really need an outside perspective.

 

Thanks,

 

James

bricks.jpg

new set up.jpg

initial set up.jpg

regulator.jpg

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Ward has always been helpful with any issue we have had.....have you sent the photos over to them?  I think they would want to sell you a burner with a lot more jets or re-jet with what you have.....how do you adjust the flame once you do get to temperature?  Does the control have a safety that will stop gas flow if the pilot or flame fails?

Is the flame color mostly blue which would indicate good air/gas mix....

 

 

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Fill the still with just water, and repeat the test. how long to boil (or 175 degrees)?

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We've been in contact with Ward and they have been very helpful.  I've attached pictures of the flame and just sent them to Ward.  Mark at Ward has given us some good suggestions, but we are looking for other perspectives.

 

Don't think I have the time/fuel to do a heat up with water.  What information would this provide that I haven't given?  Maybe I can figure it out without the time/expense of doing that. 

flame.png

under flame.jpg

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The viscosity of your mash may be dissipating the heat, and or you may be building a mash insulating layer on the still walls. I don't see any stirring mechanism which would also help. 

 

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Throw in a bunch of corn, potatoes, lobsters clams etc.. Make it a party. 

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not sure what resulted in the increase in heat up time. Get a mixer on that thing and youll seriously speed up your heat up time. 

What are you distilling? 

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2 hours ago, Roger said:

The viscosity of your mash may be dissipating the heat, and or you may be building a mash insulating layer on the still walls. I don't see any stirring mechanism which would also help. 

 

I'm distilling Rum.  Would this be a problem?  The mash has the viscosity of a wine.

1 hour ago, captnKB said:

not sure what resulted in the increase in heat up time. Get a mixer on that thing and youll seriously speed up your heat up time. 

What are you distilling? 

So, the mixer moves around the heat in the still, helping it heat up faster?  Interesting.  I thought mixers were for grain spirits to prevent scorching.   

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5 hours ago, TuftedTurtle said:

So, the mixer moves around the heat in the still, helping it heat up faster?  Interesting.  I thought mixers were for grain spirits to prevent scorching.   

Yeah, mixers can be useful to bring cooler liquid down to the bottom. Bigger the delta T, the better the heat transfer and efficiency. We used to run direct fire, without agitation and it was slow. At least in the brandy world, it is believed that the high heat and copper contact in a slow warm up contributes positively to flavor. Not sure if that is the same for rum or not. We switched to direct steam coils, still no agitation on that still and warm-up is faster, but still slow, agitation would help with that, but it is fast enough, and the flavor profile seems unaffected. We used to pre-heat our wine for the still to 120 to shorten warm-up. Might be an option for you if you have an insulated tank, drain the still through a coil in an insulated tank (or use another heat exchanger of your choice) to save the heat for the next day. My understanding is LP is typically much more expensive than NG, (although I'm sure that varies depending on location), so that could be another reason to try to save/reclaim heat.

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If you have two fittings on your tank - the drain and maybe another threaded fitting you can repurpose at the top (thermometer port, etc) - you may be able to run a quick test with a pump to see if additional agitation would be helpful.  Retrofitting an agitator to your still is going to be costly and complicated at this point, you've already had a setback.  A good agitator installed properly is probably going to cost as much as your still - which stings because it would have been cheaper to have the manufacturer add it.

So, a quick test with a pump (RUN SAFELY, Wash not Low Wines, ensure your hoses are away from the heat) will give you some confirmation that additional tank agitation would be beneficial in reducing heat up time.  Then you can explore the agitator option with some strong confidence.

If so, perhaps the manufacturer can ship you out an agitator, with the associated copper work, to eliminate most of the on-site fabrication work that would be necessary.

None of this solves the original conundrum.

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Heat trasfer is most efficient when there is a large difference in temperatures. Because your heat is at the bottom in one small area, the heat trasfer to the top of your wash is very slow.   If you were rolling the wash over, you would be putting it all in closer proximity to your heat source. 

Keep at it. It's good to see people actually distill their spirits, vs buying it in totes and warming it up. 

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That X11 burner on full power would be consuming 320,000 btus an hour.  Your tank is 100 pounds.  Propane is 21,000 BTUs per pound.  Your hundred pounds of propane will only last 6.5 hours on full power.

At 4.5 hours heatup at full power, you'll have consumed 68% of your propane.

Are you running this thing full out, or throttling back to conserve propane?

The pictures make it hard to tell how you are controlling gas flow, is that a small quarter turn valve after the regulator?  If so, it would be very difficult to dial in similar gas flow across multiple runs if you are throttling back.

Wash was really cold, still cold, windy day, slightly less gas flow - could easily add an hour to heat up, if not more.

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2 hours ago, Silk City Distillers said:

That X11 burner on full power would be consuming 320,000 btus an hour.  Your tank is 100 pounds.  Propane is 21,000 BTUs per pound.  Your hundred pounds of propane will only last 6.5 hours on full power.

At 4.5 hours heatup at full power, you'll have consumed 68% of your propane.

Are you running this thing full out, or throttling back to conserve propane?

The pictures make it hard to tell how you are controlling gas flow, is that a small quarter turn valve after the regulator?  If so, it would be very difficult to dial in similar gas flow across multiple runs if you are throttling back.

Wash was really cold, still cold, windy day, slightly less gas flow - could easily add an hour to heat up, if not more.

 

The was started at about 80 Degrees Fahrenheit, but it was a pretty cool day.  

The goal is to not run it at full power on the heatup, so we shouldn't be using 68% of the propane on heat up.  That being said, we want to connect a pipe to a larger tank.

We are running the propane at full blast when trying to get the initial boil going.  We are using the quarter turn on the rig to control the flow.  I agree we probably need something more precise.

 

2 hours ago, Roger said:

How many gallons of wash ?

120 Gallons.

 

I want to thank everyone for there help.  Agitation is something we are interested in perusing, but after we figure out what the current problem is.

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Due to the thinness of the copper in your still your still pot may not be able to stand up to the torque of an agitator over time.  In this situation you can use a pump that will handle temps up to 200F to circulate the mash around in your still.  You would need an input port and output port on your still pot.

 

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We've got a similar set up, we've been running an X-44 under one of our stills for the past 5 years.  On agitation, you're definitely going to want it.  The easiest/cheapest way is what Southernhighlander describes; braze in like a 1" a pipe either tangential to the outer wall or (easier) running down from the top of the still to just above the bottom, throw a ball valve, on it and then a 1" PT to tri-clamp adapter.  You probably have a centrifugal process pump, you just need hi temp hose, and you can recirculate out of the drain valve and back into the recirc pipe while you're boiling, works great.  On the burner, get a welding tip cleaner kit and carefully ream out the jets, if they were starved for O2 before they may be carbed up and aren't putting out what they could, this is good regular maint..  I think what's happening on heat up time is the change from brick to combustion chamber.  The brick holds in a lot of heat and really helps with the boil, but you need the bottom of the stack open enough to let in plenty of combustion air.  The combustion chamber resolves the air issue at the expense of holding onto the heat, the vast majority of the heating is now limited to the bottom of the still, so you're not getting any heating to speak of on the sides of the still.  Finally, in order to provide enough combustion air, you've got a stack on the combustion chamber which as it heats up drafts, which pulls heat out of the combustion chamber reducing it's efficiency.  This is just my take on it but what I would do with your current set up is 1) ad the recirc pipe and recirc for all the reasons mentioned by previous posters 2) ditch the vent pipe 3) put some kind of spacer between the combustion chamber and the still (1" square bar?) so the heat vents up the side of the still rather that out the stack 4) I'd play with the bricks again, try a loose stack at the bottom to allow plenty of air flow, tighten up when you get to still height and keep them maybe 3-4 inches away from the still so the heat and combustion air can get out.  The idea is make a sweater, hold the heat close to the still but let it flow.  Good luck!

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Affordable Distillery Equipment has some small agitators....could try a damper to reduce the level of heat being exhausted...

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9 hours ago, Southernhighlander said:

Due to the thinness of the copper in your still your still pot may not be able to stand up to the torque of an agitator over time.  In this situation you can use a pump that will handle temps up to 200F to circulate the mash around in your still.  You would need an input port and output port on your still pot.

 

We are planning to do precisely that with an air pump. We ordered some high temp rated hoses to set this up.

We talked to Paul at Distillery Equipment and he agreed that putting an agitator may not be a good idea based on the HOGA design.

We did a trial by manually stirring every 3 minutes today (through the manway) and we shaved a significant amount of time on the initial heating so we know that mixing will help.

We'll keep on optimizing in the next couple weeks. We very much appreciate everyone's help and suggestions.

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9 hours ago, Ned said:

 2) ditch the vent pipe 3) put some kind of spacer between the combustion chamber and the still (1" square bar?) so the heat vents up the side of the still rather that out the stack 4) I'd play with the bricks again, try a loose stack at the bottom to allow plenty of air flow, tighten up when you get to still height and keep them maybe 3-4 inches away from the still so the heat and combustion air can get out.

Thank you so much Ned!  We talked about the putting the bricks back.  I think we have a good idea how to do it.

Mrjayce is my business partner.

Thank you everyone for your input.  This week has been stressing us pretty hard.  We are moving forward with circulation and may add some heating elements and some other ideas suggested here.  In hopes that other's will be helped by this post, I'll update it later with our changes.

 

James

Hye Rum

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Is the vent pipe mounted to the back of the new combustion chamber? If so Ned is quite right.

1)Your heating surface has been reduced

2) Much of the heat is rushing up the vent pipe

3) All of the surface of the still that is not inside the burner chamber is radiating heat, cooling it down, without the bricks you have more heat loss surface.

5) remove the burner chamber and put back with bricks as original but without the copper plate. The air gap between the plate and the still was a good (bad) insulator

4) Heat up as fast as you can without scorching, less time heating equals less time for heat loss from rest of still surface.

6) Check the burner specs, I think it should be much closer to the base of the still.

6) does that regulator have the correct flow rate for that burner? it may be undersized.

 

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Great community support on this thread, just thought I'd call it out.

I'm not sure what you are paying in propane cost vs electrical, but the suggestion to preheat your wash might be something worth exploring.

Even if you are working with limited electrical capacity, a very small 2000w heater would take your wash from 70 to 150 overnight.  Granted, you would need to consider how to do this safely to prevent vapor release/boiling.  However, I'm sure you could very easily cut your heatup time in half, and significantly reduce your propane usage.

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