TRG's Steam Powered 1/3bbl brewsystem

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TRG

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This is a crosspost stolen from my original thread over at Canadian Homebrewers. I thought some of you might like to see what I have created!

I love this rig. It was a HERMS, but I wasn't overly happy with the lag with that system, and I really enjoyed some of the steam posts I've seen here on HBT, so I figured I would have a go. Disclaimer, as always... make sure you know what you're doing before you mess with steam. I'm a physical chemist, so I know the risks and energy steam can deliver...


What I've done is take a brand new 40lb propane tank - new to avoid any issues with propane explosions and the mercaptan sulfur smell associated with it - and convert it into a steam boiler. A 1" pipe flange was welded into the bottom, and a 6000W 240V element placed into the tank. The valves at the top allow me to take steam out and use it as I see fit, as well as refill the boiler. Propane tanks are rated for well over 300psi based on my research, so I feel very safe using this as a pressure vessel. Also fitted on the top is a 100psi safety pop off valve and a pressure gauge. The pop off is directed to the back, away from anyone - so there is no direct scalding risk.

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From the boiler, I ran a hard 1/4" copper line to my mashtun. Inside the MT is a copper manifold with a dozen or so 1/16" holes for direct steam injection below the false bottom.

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Now, to control steam input, I could use a ball valve... OR I could do this:

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What you see is steam input is controlled via a 120V solenoid... For testing purposes I just used one of my pump switches to turn it on and off. Next step is to connect it to my MT PID controller (you can see the PT100 temp sensor on the recirculation outlet) for precise temp control. The beauty of steam heat is that it is a gentle heat, with zero risk of scorching anything, and when you turn the steam off, heating halts immediately. There is very little lag other than about 3-4 seconds of bubbles (generally condensed steam in the line) when the steam is turned on. Once you have active steam coming out of the manifold, you can barely see it, other than a jet of heat and very tiny bubbles above each of the 1/16" outlet holes. The idea here is that steam carries a ton of energy (2260 kJ/kg) and when it condenses in contact with a cooler liquid (wort/mash), the energy is released as heat. This is a highly efficient means of heating the strike water, maintaining the mash temperature, and ultimately doing precise step mashes. Will this drastically improve my beer? Unlikely. Was it fun as hell to build? YES. But, how well does it work?

Steam Test Alpha - using silicone 1/2" hose, and ball valves for steam control. Full recirculation for accurate temperature measurements
Boiler filled to ~80% capacity (8 gallons or so) of 43F water. Turn on 6kW element to 100%. 30 minutes later, we have about 5psi of steam and rising rapidly.
Mash Tun filled with 10 gallons of water
Time / Temp / Steam Pressure / Valve opening
00m 53F 35 psi 0%
01m 56F 33 psi Cracked 20% - seemed to surge
02m 59F 33 psi
05m 70F 33 psi
10m 86F 33 psi
15m 107F 28 psi 25% - reduced surging
20m 126F 25 psi 35% - no surging, steady steam injection
25m 142F 24 psi
30m 157F 22 psi
35m 172F 20 psi

To me, this is a fantastic result, but we found that there was far too much condensation in the 1/2" silicone, so we upgraded it to 1/4" copper hard tube for volume as well as safety reasons, allowing for higher steam pressures (not higher temperature, just more of it in the tank - reducing any recovery time, or pressure loss).

Steam Test Beta - 1/4" copper line, solenoid valve orifice 3/32", all valves wide open
Same ten gallons of water in the MT.
Time / Temp / Steam Pressure
00m 93F 50 psi
05m 110F 46 psi
10m 126F 42 psi
15m 141F 40 psi
20m 155F 39 psi
25m 168F 38 psi

Again, this is fantastic. Compared to what? Well I found that the HERMS system that I had used before was extremely slow, and didn't seem to be very efficient. I had troubles maintaining temps and overshot some with strike water. Maybe it was due to the 3/8" copper coil, I don't know. I think that this upgrade will greatly aid in the process. I imagine that heating the mash will be even quicker due to the density of mash versus 100% water, reducing the heat capacity of the whole.

One thing to note... at full throttle while injecting steam... this thing is noisy! The rumble from the MT is intense as the steam condenses and releases its heat. I love it!

Now I have brewed two batches on this system using step mashes (mostly just a protein rest at 122F, stepping to mash temp ~149F, then a mashout at 168F) and it has worked flawlessly. The steps are quick and painless, and heat distribution is easy since my pump is recirculating throughout the mash. Couple more pictures here for you guys...

Mash...

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Overall system

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Wow, I love it. I would consider something like this for my big system. I don't know anybody who would agree to do the welding on that tank though.
 
Thanks!

It helps when your Brother-in-law is a journeyman welder with a kegerator that needs filling... ;)
 
Here's a quick video of it in operation.

 
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The propane tank is steel, right? Bad idea if is as it is going to rust and fail at some point. you're also going to be injecting rusty steam into your mash after the first few runs. 50 psi is almost 300* and is serious stuff and I would check the pressure/temperature ratings of all your equipment to be sure they are rated for steam and those pres/temp. Do you have any level protection in the tank to shut the system down if you run low on water? If the level drops enough the element is going to heat the remaining water faster and faster and increase the pressure rapidly. I think anything over 15psi normally requires an engineer onsite for good reasons. Be safe and keep up the good work.
 
Thanks! Yes, it is steel. I'm not too conerned about it yet, as I am planning on installing two or three zinc anodes to combat corrosion. This should solve that problem.

I did come very close to ordering some stainless tank caps to build one out of all SS. They were quite expensive. Auber Instruments do sell a pressure PID controller with a sensor that I plan to use, this will make this system very safe. Dial in 20-25psi on the PID, and you don't have to worry about it going too high on you.

Regarding the level in the tank - I fill it to the valve you see on the side of the tank. Roughly 90% full. The element is a compact fold back element that is just over 12" long. So to run the element dry, I would have to boil off half of the water. At most for my longest brewday, I boiled off about 3"... so I feel very safe without a low level prevention device.
 
The anodes aren't going to protect the portion of the tank that isn't in contact with the water or when the water is drained out after use and they aren't absolute protection. The relief should also be pointed down to prevent shooting the relief at someone or knocking the tank over. A tall quarter keg would be a good option that you wouldn't have to worry about rusting out.
 
Just for some ideas:

http://hbd.org/brewsandviews/messages/20001/20367.html?1076162311
https://www.homebrewtalk.com/f51/yuri-goes-big-steam-new-boiler-point-use-water-heater-125953/

If you have pumps you can also inject steam inline using a diffuser. I think it's also much quiter.

It's also a good idea to have a steam trap to protect the pressure gauge.

kladue has one of the coolest and most sophisticated brewing systems, and his flash boiler is in my opinion the best way to make steam for brewing.

https://www.homebrewtalk.com/f51/phase-2-brewery-build-progress-shots-70821/

Here's another thing I've come across, though the price is a bit crazy:
http://www.brewsteam.com/index.php/products
 
The electric heated kegs and now a propane tank conversion suffer from the same problems, not enough heat input to be really useful, and dangerous as all get out. The main design problems with keg and tank boilers is the material strength at 325+ degrees, and the wrong type of relief valves that can not release pressure fast enough.
I looked at these and went on to build tubing type flash boilers that are not pressurized and can tolerate extreme abuse without explosion ( dry fire to orange hot and quench with full flow of cold water). Second reason was the output was beyond 10Kw, more than practical with electric heating.
Last reason was < 60 seconds to full output and stable temperature from cold start with water or steam generation.
 
I like the flash boiler you built kladue. I wish I could do this with electric, as I prefer electric vs gas. I don't think it could be done with electric heat though...?

It may be dangerous, but I feel it is totally safe below 30 psi. Once I connect up the controller to maintain pressures, I will feel even safer. So my question regarding the tank is from ambient to 300F, how much is the steel weakened? If the propane tank is rated for 300+ psi, then the temperature would have to bring the tank below 25% of its original strength. I do not think this is the case.
 
While the original tank may have been rated at 300 psi ambient temperature, you have changed the tank by cutting holes into it and welding new openings. The new safe operating pressure will not be anywhere near the original rating now. The other basic problem is still the heat source input, and thermal storage of the water in the tank, is too small to be useful. Yuri and others have already found this out years ago if you check older threads for steam injection systems.
The steam injection craze started back in 1995 with pressure cookers, and has resurfaced over the years since in variations on the same theme. To my knowledge they all suffered from insufficient output for large temperature steps, and the steam injection into the mash causing a lot of noise.
 
Nowhere near its original strength by welding two fittings on? Do expand. Steel and temperature information is easy to find, and from what I found shows steel strength beginning to weaken above 500F. I'm not anywhere near that temperature, so I'm not sure what you mean about it being nowhere near its original rating.

I disagree that it is too small to be useful from the use I have put it through thus far. It worked very well to heat strike and sparge water as well as maintain mash temperature on two ten gallon batches for me now. I have read the older threads on steam systems. If noise is the only real factor holding this system back, then I'll just turn up the stereo while I brew.
 
The tank was rated at ambient temperatures without being filled with steam. New corrosion mechanisms come into play in this scenario, such as stress corrosion cracking. I wouldn't use a propane tank as a pressurized steam boiler, and I'm usually pretty gutsy with winging it or giving the benefit of the doubt. I can't see why you need pressurized steam in your case anyhow. Are you boiling wort with it?
 
I defintely don't "need" pressurized steam. But I like how well it works for heating the mash/strike water. That said, I've used this system about a dozen times, but am in the process of building a new flash boiler. So I am not worried about this tank failing in the next few brews, but I do agree, in the long term, this is not the best solution.
 
Having built and used flash boiler brew systems, the upside is the brewing side water heating and steam for stepping work great, down side is it is easier to just direct fire the boil kettle as direct steam injection for boiling will not work. For boiling, internal coils and jacketed keg have been built and tested, both work but are a lot of effort to build and operate, and are not any faster than direct fire as boiler output is limiting factor. With the automated brew system it is about 4 minutes from cold start to dough in for a 6 gallon batch, 6 minutes for the older manual control brew system with the smaller boiler. manual control of the flash boiler is as simple as needle valve for water flow and needle valve for gas flow, flow meters are optional but advised for water flow into the boiler for repeatability.
 
My kettle is electric fired, so I will not need steam for the boil. This is exactly why I think the flash is exactly what I need. Once I begin the build, I will start a new thread - thanks for all of the info Kevin.
 
One plus side to propane/n.gas pressurized steam for boiling is that you could build a more efficient firebox/boiler for the steam. For many of us, n. gas is substantially cheaper than electricity, but we tend to throw most of the energy away with the burner-under-the-pot setup. It would be fun and interesting to boil with steam, but would only be more efficient if you were using gas and had a nifty boiler for the steam.
 
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