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A few questions on Boilers

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As I have been trying to educate myself on boilers, a few questions have come to fruition that I can't seem to find an answer for. I was hoping some folks who have been down the road of purchasing a boiler would know the answers. 

#1: Is a blow down seperator necessary? From my understanding it seems like an integral part for maintaining safety within the still house/boiler room. 

#2: What is the ball park installation cost of a boiler? We are looking at a 60 HP boiler.

#3: Opinions on Sellers or Aldrich boilers? These are the two manufacturers we have narrowed it down to. I like that Sellers doesn't need any chemical treatment, but I like the footprint and the 5:1 turndown of the Aldrich better, vs. the 3:1 turndown on the Sellers.

Thanks.

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You should call Saskatoon boiler @ 1306 652 7022 ask for ray graves this fella is 70 years old and 4th generation boiler maker I would guarantee this guy has forgot more about steam than most people know . Give it a try one call to ray will shock you , no chinese remanufactured stuff in there place . 

Tim

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Blowdown separators are more about what the local inspector requires, and may be unnecessary on smaller boilers. We do not use them.

https://www.maddenmfg.com/blog/What-does-blow-down-separator-do.cfm

Both the brands look decent. The Sellers being a one pass Firetube design is interesting. I prefer the Scotch Marine Firetube boiler to any other design in terms of long term ruggedness and reliability. There are a lot of good ones out there. I do not care for Cleaver Brooks in the least and they have been one of the most problem laden brands I have ever worked on. Same with Hurst, which is another brand I'll never run again. For 60 HP I would definitely go with a Scotch Boiler. This guy has some good resources: BrewingwithSteam.com . I have seen a good many systems in the field which are not set up correctly with respect to how the feedwater and condensate return are handled. its important to realize that things can seem to work in these instances, but they are not working correctly and in some cases it can get dangerous. You are much better off in terms of controlling corrosion if you can keep your system active 24-7. The best way to do this is to use it to heat water for all you hot water needs. If you are shutting down all the time and going cold this will present a challenge on your chemical treatment that can be difficult to solve. All Steam Boilers require chemical treatment and daily blowdown. If you have never run steam before its a real good idea to take at least one class, and do some serious reading about what not to do with steam boilers. They can become very dangerous in the wrong hands very quickly. A duplex return station with isolation capability gives you redundancy and is 100x better than a single pump system because of this one simple fact. A major lot os steam loaded equipment is designed with the condensate outlets too low. Ideally you need to port condensate into the return station in the top of the vessel. I have brought this fact one one MFG's attention and he is making corrections. Fully modulating fire control is best. This is an example of a return station set up pretty well out of the box: https://fabtekaero.com/condensate-units/

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I would be wary of anyone that says the boiler water doesn't need treatment. Unless the boiler feed water is pre-boiled, which is a pretty old-school way to do it, boiler water is going to need treatment. We were sold partially on the same reasoning: you don't have to treat the feed water to this boiler! Well, two corroded tubes in a six week span (boiler is only a year old), it turns out we do have to treat the feed water. I would err on the side of caution and spend the $500 for a chemical feed tank, and save yourself the nightmare that is re-tubing a boiler.

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All Steam Boilers need chemical treatment, and not just for the boiler but often times you are treating the steam which treats the condensate return system. Corrosion of the return system is very common which can accelerate corrosion in the Boiler proper.

This is typically done with neutralizing amines, but filming amines may be indicated as well.This is especially critical on intermittently run systems. I would want to be educated on their logic from all points to understand why they would say no treatment is needed with respect to their design and whatever the local water profile may be. In Texas as an example, we were dealing with very difficult hard water. The spring source here in Utah is about 500x better in this respect. I cannot imagine how no oxygen scaveneger or adjustment of the condensate ph would not be needed, but I am willing to listen to the MFG's explanation on the matter. Water needs to be at 170F or above to keep dissolved oxygen moderated.

 

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Thanks for the thorough replies. I have asked the manufacturer about their "no chemical treatment" system and will reply here with their answer. I know they are the only boiler maker that I know of that has this system on their boilers, or at least on the H-Series boiler. 

Starcat, you mention using the boiler for all our hot water needs, and this is actually what we are planning on doing. We will have a 1200 gallon mixing tank for creating our rum wash and would like to use the boiler to heat our hot water, so will a condensate return be beneficial for this application or is there another item needed to turn this boiler into a hot water heater? From my quick reading on condensate returns it is primarily used to return condensation back into the boilers feed water. Thanks for helping out, we are expanding from direct fire stills to a steam jacketed still, so this is all new to me, but I want to make sure I know what I'm doing.

Thanks again for all your guys' help so far. 

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Blow down separators and water treatment are needed to prevent your boiler tank, tubes and other parts from needing replacement caused by calcium and other mineral build up.  If you are blessed with soft water from the tap, and just filter it for sediment removal, you might make a case to go without.  However, it also depends on the boiler as lacking these things you might void a warranty.   Also, even with soft water from the tap and sediment filtering your boiler part life will be less than if you have chemically treated water and blow-down.  

You can do without a condensate return system, but that will increase your boiler water use, your water waste and your cost of boiler operation as you are not returning the heated water from the steam condensate back to the boiler feed tank.  It is a fixed vs variable, short-term vs long-term cost-benefit decision.

If you want to use the steam injection into a mash, you need a potable water steam boiler... expensive.  Otherwise the water used in the boiler is absolutely not potable.

This was taken during installation... a 5-week project. 

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My 35 HP boiler was $60k including all parts and components and about the same for installation.  C4 pipe fitter/welders in CA are billing at over $150 per hour.   One thing I did not end up doing and I might do today is to consider using Pro-Press fittings instead of welded steel pipe.   But Pro-Press only goes to 4" so if your steam header is greater than 4" it will require welding.   The economics for this would depend on the length of your steam runs and the number of fittings.   I could have done this work myself and probably saved $15k... but the other major problem with steam boiler installation is your local building official.  Frankly they tend to be idiots about steam boilers... over-worried given the ASME certifications and all the fail-safe components... and unable to wrap their head around the difference between a low-pressure and high-pressure system.

This was the most PITA part of my operation, but now I am benefiting from low cost of operation and high reliability in process.

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Patio Daddio

Good post on boilers.  One little thing though. You can use sanitary filters to steam inject from a regular boiler.

 

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Thanks for the clarification PatioDadio. This thread is really bringing me up to speed.

As far as the "no chemical treatment' on that boiler, the representative I'm in contact with told me due to the materials of construction (copper clad tubes and a thermoplastic lined tank) there is no need for any chemical treatment to maintain the boiler. However, and especially due to our high calcium content, they still recommend the use of a water softening system for our incoming water. Lastly, depending on our steam distribution system and still materials, we may want to check there are no chemical treatment recommendations for those items. I'm hoping someone with a Sellers H-Series boiler chimes in here and lets us know how their system has been doing.

 

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Good post on boilers.  One little thing though. You can use sanitary filters to steam inject from a regular boiler.

Thank you Southern.  That makes sense I think as long as there are no chemicals added to the boiler feed water. 

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We don't use any feed water chemicals.  We use DSI through a sanitary filter.  We realize that it will ultimately destroy the boiler, that's what happens to boilers.

Look at the big systems, Vendome mash tuns - DSI.  Vendome continuous stills - DSI.  Between these two processes, you are talking about the majority of steam not being condensed and returned, huge feed water use.

My water guy tells me that he's seeing reverse osmosis boiler feeds becoming more common for food-contact use.  Preferable and simpler than dealing with lots of chemicals.  If you are already spending money on water treatment systems, why feed your boiler tap water?

If you are returning *ALL* condensate to the boiler, and are not losing steam to the atmosphere - realize this reduces your need to blow down.  If you are blowing down every day on a boiler that isn't losing steam, you are destroying your boiler prematurely.

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There are several ways to heat water for plant usage, all of which I have worked with. They are HLT system.Shell and Tube HX with pump, which can be ported to an insulated vessel in a number of ways. I have also run tanks that have tube bundles integrated, so you have steam tubes surrounded by a pressure tank as in a big hot water heater, heated by steam. Sure Store makes vertical units that are HW to HW, and I am sure someone makes one for Steam to HW. We had some big horizontal old school ones at A&M. A properly configured condensate return station is really needed for ALL Steam boilers. In our case you can see I have custom fitted a receiver with all necessary controls and essentially turned it into a " Return Station." This is for several reasons, but mainly because of the way low down entry point due to having insufficient fall from the still. It should also be noted and this has been mentioned before that the condensate outlets on a major lot of this gear are set way too low to the floor, and this is a problem. Even the smallest receivers generally are entered around 10-12" off the floor. This means you lowest condensate outlet  needs to be higher than this dimension, or you will be forced to enter the bottom of the receiver which is not ideal.

The OEMs need to start thinking about minimum heights to achieve gravity flow into a receiver under typical setups on a single floor level. Your really need to return all of your condensate except for blowdown to the system. I pointed this out to one of our OEMs and he made a very good adjustment on the last piece of gear we had to replace.

The return station is integrated with your Fresh Water makeup, and your chemical feed.

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22 hours ago, starcat said:

The OEMs need to start thinking about minimum heights to achieve gravity flow into a receiver under typical setups on a single floor level. Your really need to return all of your condensate except for blowdown to the system. I pointed this out to one of our OEMs and he made a very good adjustment on the last piece of gear we had to replace.

This is one area I am definitely not happy about.  My floor around my steam heated vessels is a mess of condensate return plumbing and the tank-pump.  It makes cleaning in that area very problematic.   And the black pipe holding the condensate produces some rust which then stains the floor.  

We have beautiful shiny stills and tanks, plumbing and electrical runs are symmetrical and straight... and then this mess of black pipe connections with the pump-tank on the floor that almost looks like a child designed it.   I agree with you.   Ideally all steam jacketed stills would have their own condensate tank and pump hanging off the bottom of the steam jacketed boiler tank and then the only connection would be a single pipe to the condensate return header.   

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 If you are already spending money on water treatment systems, why feed your boiler tap water?

RO uses a lot of water... so you are somewhat defeating the purpose of condensate return to help prevent water waste.  But in my neck of the woods I would not DSI the tap water.

Correct me if I am wrong here, but DSI requires high-pressure steam?  

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We run 2 Miuras in tandem using RO water and all stainless steam lines so we don't have to blow chemicals into our mash on the columns. We believe in it so we did it. We still have a blowdown separator. Blowdown removes garbage from your boiler and to my understanding is necessary no matter what boiler you run, there may be a design I am unfamiliar with that doesn''t require I cannot speak to what I don't know.

 

Miura's are expensive but the best (most efficient, quickest for steam, and easiest to maintain), I would buy whatever I thought was better and this is the best I've found. Just my .02.

 

Good luck.

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I posted a link about blowdown separators above. They don't do much of anything on small systems really. We did not have a single one on the College campus I managed for Texas A&M.

They are more about modern codes and whatever control trips the local inspectors are into. Most Micro Breweries and Small Distilleries discharge into a separator tank of fairly large size. This is a buffer zone.

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   Concerning the condensate return connections on stills.  We raised ours, on most stills, from 12" to 15" to 18", sometime back.  I would love to make them 24", however, if I standardize that in my designs it would lead to lots of other issues, with most customers. 

   Most of the time we barely meet the customers height restrictions as it is. Raising the condensate return connect higher would mean that we could not meet the height requirements that many of our customers have.  Also if the still is a 200 gallon or larger, it makes the manway much harder to access because of the height.  Also with stills with offset columns, the base of the offset column must be high enough above the liquid level in the pot, so that gravity will overcome the pressure created by the liquid level above each plate.  On our ultra pro vodka stills, this means that the base of the column must be 18" to 20" above the liquid level in the pot because there is 17" of juice above the plates at high reflux.  Anyway, these are the reasons why most still manufacturers have their condensate returns at around 12" above the floor. 

I would appreciate any suggestions that anyone has concerning how to overcome these issues to standardize a higher condensate return connection.

 

Thank you.

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The centerline of our pot outlet ended up at about 9.5" off the floor which is, so down low man. I had to use a Spirax FTI trap which has outlet at same height as inlet to deal with this. We are dealing with a Still Dragon rig. The problem is too many return stations have the inlets too high off the floor. This outfit " Fabtek  " has some interesting SS units and a low boy advertized, but currently without details on the websight: https://fabtekaero.com/

The inlet on the receiver I bought is at 10.5", so we came in the bottom. So again you can turn a receiver into a lowboy condensate return with a few simple MODs.

Back to flash separators. I am definitely not knocking them. They are good if you have the latitude and space to install them. See 2018 UMC 1001.4 for details. If you are blowing down into a floor sink, you can run cold water from another source during blowdown to moderate things.

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We drilled a hole in the steel condensate receiver tank and welded on a ferrule.  Even with that, we have about 5 or 6" of "lift".  Glad I'm not the only person here that has been ticked off by that.

I know of a few stills in operation that have a few feet of lift, using steam back pressure to return condensate.  I know of one going back to the stand-mounted Fulton condensate return - that's not sitting on the floor, but about 3ft up.

I can't imagine a few inches is any real problem, even at very low pressures, but higher amounts of lift could cause condensate to be pushed over to the receiver in bigger slugs.

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Here is an example of a " lowboy " return station with the inlet listed as 16" off the floor. 16 Inches being still too high in my view:

https://fabtekaero.com/wp-content/uploads/2013/08/Condensate-Return-Tank-25-Gal-SS-Duplex-Pump.pdf

If the geometries are too far out of line you can flood your steam jackets to that level. The thing to do as has been noted, is either custom fit OR possibly get one of these OEMs such as Fabtek to work with you as a " Systems Builder " to design a return station that works, and works well under dimensional limits. If you notice the Blue Weinmann receiver I posted above, we are entering at the bottom which is about 1.5" off the floor. While this is not ideal, its better than keeping the entire condensate run flooded back to the still and then some. In this case the return line will only flood back to whatever the current tank level is running in the sightglass on the pump side so there is still fall from the source into the tank. The bad thing is that line is flooded on the off cycle. Its very easy and straightforward to refit this type of receiver to be a full blown return station.

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Why wouldn't you just use something like of Hoffman Watchman returning to a larger condensate tank?  Or directly back to the boiler if it's the only condensate generating device (it doesn't have a water feeder, not ideal).  It's about 6" off the deck, or you could plumb a tee into the lower drain port, which is at ground level.

 

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I think the issue is getting them and the pipe runs off the floor so it can be cleaned easily.   Seems to me that the best design would be the condensate falls to a still-integrated tank that is under the pot and integrated with a pump and a float switch.  

Maybe just bolt a stainless steel version of that low profile Hoffman unit (need XP) to the underside of the still.  Then it can be wired along with the agitator.  

I think the problem with this is that it then gets the still manufacture into a new subject matter that they might not want to be in.  However, if you think about it... it is really just drawing a new line in system domain ownership along the process continuum.  Steam goes into the pot still jacket and there is a low-point drain for the condensate to exit.   Today the steam boiler equipment people come it to provide solutions connecting the steam equipment to the still equipment condensate drain.   The shift would be that the steam boiler equipment people connect to a condensate pump outlet that is integrated into the still equipment and that is situated at least 16" above the ground.

Said another way, the steam boiler people generally don't own much in aesthetic consideration nor care much about how one might clean around their proud mess of black pipe.  The still manufacture people do care about these things.  

I don't have a problem with the steam boiler people working on the steam boiler, but I would like to limit their work around the stills. 

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Not sure if I'm following this all correctly, but we just have our condensate plumbed into a receiving tank with a float switch that then pumps it back to the condensate tank next to the boiler?  Same unit that Silk posted an image of.

Our still is against a wall, and the tank is on the other side of the wall, so it's about as explosion proof as you can get.

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