Brewery boiler question - free beer for best answers!

J Diamond

Hi, I'm a mechanical engineering graduate student who managed to land himself a summer job working for a Southeast Michigan microbrewery on a major expansion project (great gig if you can get it). One of the projects includes doing *something* with their process steam system, and I'm trying to determine what that something should be. A reliable source tells me that the "cream of the crop" of boiler and heating experts hang out in this forum. I'm hoping that I came to the right place.



Current Setup

The current boiler is a <a href="http://i.imgur.com/Sgyw5.jpg">Fulton ICS-030-A</a> 30 HP (1 million BTUH output) tubeless natural gas boiler, built in 1996. It's rated for up to 150 psi steam, but has low-pressure fittings, and is currently set to operate at 25-30 psi. It provides steam to the hot liquor tank (HLT), a 1200 gallon stainless steel steam-jacketed water tank. It also provides steam to the brewkettle (BK), a 650 gallon steam-jacketed atmospheric boiling vessel.



The outgoing steam and condensate return lines are completely uninsulated, causing the brewhouse to get pretty uncomfortable in the summer. Also, the boiler seems to be short-cycling very badly: turning on/off about 14-15 times per hour when connected to a load, and about 4-5 times per hour when load is disconnected, but turned on (is this normal??). A modulating burner retrofit kit is available for this model for about $3,200 plus labor, and I'm told that this will save about 6% on energy costs, plus major reduction on the wear and tear of the unit. Can anyone confirm this?



So, the highest demand on the boiler takes place in the one hour per brew day (3-4 days per week) when it must heat 650 gallons of wort in the BK from about 150 to 218 degF, while simultaneously heating 400 gallons of water in the HLT from 55 degF to 175 degF (for the next batch). According to my calculations, this requires 325,260 BTUH and 400,320 BTUH, respectively. Done simultaneously, it means that we need a boiler capable of over 725,580 BTUH output, making sure to account for losses. So, it would appear that 1 million BTUH is about the right size for our needs.



However! A new solar thermal panel system, paired with a tankless water heater is expected to provide our hot water needs up to 130 degF. So, this means that the heating in the HLT should only require 150,120 BTUH, for a total of 475,380. Now 1 million BTUH seems a bit over-sized.



It is unclear whether or not the boiler needs to provide over 15 psi steam. We tried an experiment where we reduced the steam output to 15-20 psi. It heated up the HLT to the requisite 180 degF without trouble, but it struggled to heat the contents of the BK to the requisite 218 degF (wort boils at a higher temp than pure water). So, the controller had to be adjusted to 25-30 psi, at which point it had no problem getting the BK to a good boil in the time allowed.



This is strange because I'm told by others that 15 psi is more than enough for a brewery. Now, the steam pressure controller adjustment is pretty coarse (about +/- 4 psi resolution on the scale).



Proposed Setup

The first and most obvious ingredient to the solution is to insulate the steam and condensate return lines. I believe that 1" fiberglass should do the trick. Next, due to other expansion goals, the boiler can no longer be in its current position. So, any option which keeps the current boiler must take into account the cost of moving it to a different location in the brewhouse. Either way, a new hole has to be put in the roof.



Option 1

Keep current boiler, install modulating burner retrofit kit, move it to new location. I'm interested in incorporating boiler flue stack heat recovery.



Option 2

Sell old boiler, purchase new boiler with modulating burner, install in new location. Consider boiler flue stack heat recovery.



My questions:

Why is 15 psi not heating the brewkettle? Is it likely that the gage is incorrectly reading 15 psi?

What are your thoughts on the size of the boiler? Is it over-sized?

What do you think of Option 1 vs. Option 2?

Can you suggest a ballpark cost for each option?



If you've read this far, you're my hero. If you take the next step and provide some solid, specific, and quantitative answers to my questions, come to the brewery, and I'll send you home with a growler of your choice on my coin. Just click the "contact this user" button to get in touch.



Thanks

moneypitfeeder

I'm no pro,

Here's  some info for you to peruse, if you already know all of it I apologize. I just figured I'd give you something to chew on till the pros weigh in.

http://www.nwfpa.org/nwfpa.info/component/content/article/37-boiler/68-minimize-boiler-short-cycling-losses

As a sidenote, (I'm just a homeowner with a steam system) when my boiler was running all the time for several minutes then off for a few back on again, I researched our thermostat and realized the setting was never programmed for optimal steam cycling.

Also, you state your trying to get your wort up to 218, steam at low pressure shoots out at about 212, but even in a low psi setting if you don't have the supply pipes well insulated, the steam leaving at 212 is trying its best to cool down and turn back into condensate. Could it be that your system is set up properly, but without the insulation the steam is just cooling before it can get to its destination? Are all your vents working as they should? You need to move the air out before the steam can get there. And yes if you doubt your psi gauge I would most certainly change that so you know where your at before adding any upgrades. Best of luck to you, and hopefully the pros will make sense of your predicament. 

Steamhead

What burner

is on the boiler now? 

Gary Jansen_4

More info needed

Some of your posting seems odd. You stated the boiler cycles 15 times an hour under load, and 5 with no load. Makes no sense. Here in Wisconsin I would be very surprised to see insulation of less than 2" thickness. It's very common here in this type of application to see 21/2-3" of high grade fiberglass insulation on your piping. 15 lb steam should be more than adequate for your application. I would question your sizing and configuration of existing piping. Mod burner would help somewhat with smoothing out your cycling problems, but again you need to look at your entire system and how it operates. How about posting or sending a piping diagram? Regards, Gary

Gary Jansen_4

In regards to your solar

I'd be real careful about the solar always having 130 F. water available for your needs. Unless you have one hugely over sized system, I wouldn't count on having that water available more than 50-60% of the time. And what if it goes down for unknown reasons. I probably would not include it in the load calculations at all and would consider the solar a bonus. Regards, Gary

Charlie from wmass

Barrington Brewery

in Great Barrington, MA is all solar for their brewing. I will get you a link later today. http://www.barringtonbrewery.net/

Greg Maxwell

Process Boiler

I have only had limited experience on process boilers, and they were for a label company that made tags for clothing, and a laundraumat, but my recommendation would be to contact the mechanical contractor who installed it to find out what the requirements were when the system was installed, so you will have a starting point, then contact Fulton, they will be a big help, as this is what they do. They will steer you in the right direction, and will be able to answer a lot of questions.

Mark Eatherton

The art/craft of brewing...

is second only to the Lost Art of Steam Heating...



As a side, I had some involvement (after the initial fact) on a local brewery. The owner had a degree in mechanical engineering from an agricultural school. I pointed out the fact that there were no vacuum breakers at the vessels. He told me that they NEVER completely isolated them, and that they weren't necessary because there was a central vacuum breaker that was located at the boiler...



Whatever....



He didn't take ANY of my recommendations to heart. Some time later, a friend of mine was at the brewery purchasing their goods and noticed a wadded up ball of stainless steel that was formerly a mash tun... So much for never allowing complete isolation without a vacuum breaker intact.



Steam can be relatively simple, and usually when there are "issues" like you are experiencing, someone or something is violating these basic rules.



Steam and air can NOT occupy the same space. (bad/poor air venting)



In order for steam to flow, there MUST be a differential in pressure and temperature. (bad traps not allowing this required differential, scaled up heat exchangers suppressing heat transfer)



The boiler MUST be matched to the loads. If the loads exceed the capacity of the generator, NOTHING gets accomplished. Conversely, driving tacks with sledge hammers will cause short cycle problems.



Insulation is a MUST in order to get maximum power/efficiency out of the system. Waste not, want not.



Chemical treatment of steam commercial systems is a must, and if not properly done, will lead to ALL kinds of inherent problems.



Your organization would be light years ahead to hire someone like Frank Wilsey (Steamhead) to come out and take a look at your operations and have him make recommendations. (You may have to pay him more than just beer). My experience with smaller breweries is that there is a general lack of knowledge on the part of the brewery operators as it pertains to the operation of the steam plant "If it's hot don't mess with it..."



Larger breweries hire and maintain a "staff" of engineers to operate their physical plant. The Coors Brewery in Golden Colorado hired a company to run its steam plant (electric power AND heat) and the seasonal efficiency of their steam plant is above 80%. They COMPLETELY use the heat that is generated by their steam plant until there is little to no energy left in the fluid stream.



The typical seasonal efficiency of a comparable electrical generation steam plant has been pegged at less than 40% on a GOOD day...



IF, and that is a BIG if, you MUST have the higher operating pressures, you would be wise to put a control on your steam plant that can raise and lower the operating pressures based on what loads are on line instead of maintain the boilers at worst case scenarios.



Keeping the physical plant in a hot ready/steady state is contributing to the standby losses (5 cycles per hour with NO load is a BIG waste, and hard on the equipment) and results in considerable unnecessary waste. Getting the system to operate on the lowest pressure possible is going to create the greatest energy conservation. Adding a variable capacity burner CAN lead to some energy savings, IF it is done right. Done wrong, it can lead to higher operating costs, and also contribute to the early demise of the steam generating equipment.



You HAVE discovered The Worlds Best collection of steam and hydronic heating experts. Put them to use.



And welcome to The Wall....



ME

J Diamond

Boiler activity plot

I'm really impressed by the quality of the answers I'm getting. The tech services fellow at Weil-McLain was right to tell me to come here.



Gary, in response to your request for more info, I've included a screen shot of a plot showing the activity of the boiler's inducer fan. This was the method I used to measure the boiler's firing activity. When the fan is on, the boiler is firing. When it turns off, the burner is off.



The closely clustered lines represent times that the boiler is actively heating the steam jacket of the HLT and/or the steam jackets of the BK. The loosely spaced lines represent the times when the boiler is on, but not actively heating anything (just circulating steam through uninsulated pipes.... sigh).



As you can see, the brewery's steam control strategy is somewhat lacking. On this day, around 11 AM, a brewer started to heat the HLT in preparation for brewing the next day. At about 3:15 PM, the HLT was found to be boiling, so the valve connection to the HLT was turned off. The boiler is left on (why? I don't know... it's always been done this way here, but it seems like a waste of gas).



The following morning, the HLT has cooled  down to maybe 205 degF from 212 degF. Cold water is added to the HLT until they get the desired final temp of 175, and mashing can begin. The next dark cluster of lines represents the simultaneous heating of the brewkettle and new cold water in the HLT, to start the next brew. Then repeat.

patrick linhardt

tempting offer indeed

I agree with ME, start with the basics. On your short cycling issue, there are two safeties/operating controls that can and will turn your boiler off during a run cycle.



Is the boiler reaching pressure and shutting the burner down from the operating pressure control, or is the water level of the boiler dropping below its operating level and the low water cut-off shuting the burner down?



We can start troubleshooting the cycling problem when we know which control is cycling it off.



I have experience with less than 15# of steam pressure operating a micro brew with great results here in Cincinnati. Required temps as I recall were very similar to yours.



Patrick Linhardt, Linhardt's Field Guide to Steam Heating

J Diamond

steam shut off control

After setting the boiler operating pressure to about 30 psi, I can stand in front of the boiler and observe that when the steam pressure gage reads about 25 psi, the burner kicks on. It stays on for a couple minutes until the pressure reads 30 psi again, when it shuts off.



I think I'm beginning to see an answer taking shape here, but first can someone answer this question:

If the steam lines are un-insulated, would the steam pressure reading at the boiler be significantly lower than the steam pressure at the point of use (i.e. brewkettle or hot liquor tank)?



If the answer is yes, then what appears to be happening is:

1. Boiler kicks on and rapidly reaches 30 psi.

2. Steam is traveling from the boiler to the load, but rapidly losing pressure in transit through uninsulated pipes.

3. Steam reaches the load at a much lower pressure than 30 psi.



If this is the case, would it make more sense to

1. Insulate the pipes and replace the boiler with a low-pressure (15 psi) model? On that note, is it possible/cost-effective to get a 15 psi boiler with a modulating burner?

2. Buy a modulating burner for the current model? (part cost = $3,200)



Thank you for all of your help, guys. I'm serious about the free beer offer. Just contact me and I'll hook you up if you stop by

patrick linhardt

clarification please

Do you mean to say that the steam pressure is higher at the boiler and lower at the point of use? That would be typical for any system, but the difference in pressure would be greater with the un-insulated pipes and/or undersized pipes that create excessive pressure drop.



How does the water line in the gauge glass look? Does it remain relatively steady, or does it bounce up and down? Is there any moisture running down from the top of the gauge glass? These are indicators of a clean or dirty waterline, which is the first thing to check on any steam boiler.



Patrick Linhardt, Linhardt's Field Guide to Steam Heating

J Diamond

clarification

Yes, that is what I meant to say. I'm starting to wonder if our experiment where we tested the brewkettle heating at 15psi failed because the steam was, say, 5 psi by the time it reached the brewkettle.



I'm going to make a service request to have a gage installed in the line where it meets the brewkettle to answer that question.



I'm not at the brewery right now, so I can't look at the gage glass, but I will check on Monday. I seem to recall seeing some moisture on the outside of the glass.



Aside from the water level and moisture on the glass, what other things should I ask the steam service tech to look at while he's there?



Also, I'll try to put together some sort of piping diagram. Sounds like a good challenge...



Can someone explain why I wouldn't want a mod burner? It sounds like insulating the pipes, turning the boiler down to 15 psi, and using a modulating burner to avoid short cycling is the easiest and most logical solution. What are the possible downsides?



Thanks, guys.

crash2009

Short cycling

Has anyone checked the returns for proper flow?  When you reduced the pressure, the HLT worked OK, but the BK slowed down or stopped.  My beer guess is partially restricted return line from BK back to system.   



 

J Diamond

difference in heating loads

That's a good idea. How would I check for this?



My first thought is that this is probably not the case. The difference between the two heating tasks is that the (sealed) HLT only needed to be heated up to 175 degF, while the BK needed to be heated to 218 degF, with the top lid off.

J Diamond

result of experiment

With the gage on the boiler reading 20 psi, I read the gage on the steam line just before entering the brew kettle to be 13 psi. This is enough to heat the brew kettle. Does this mean that if the lines were insulated and/or shortened (we're planning to move the boiler location right next to the brew kettle) we'd be able to get away with a 15 psi boiler?

crash2009

Laser thermometer

might show a difference in temp just after a restriction.  A pro would likely just take it apart and look.  Ask your service man.

Charlie from wmass

To run a lower pressure

You need a larger diameter pipe to get the same pounds of steam to the kettle. What is the project btu usage of the kettle?

SteamAE

Status of this thread?

I am a steam applications engineer that has been in the business for 10 years now. I just created an account here and noticed this thread, as ended mid july. How are you doing with this? I would like to provide my comments if you are still working on it and need some answers. Let me know and I would be happy to provide my thoughts, and subject myself to the dogs... ;-)

crash2009

SteamAE

What is your opinion on whats going on with this beer brewer?  I'd like to at least see someone get the free beer. The bark is worse than the bite.

Henry

Steamed

ME is right on but there can be another or several other problems. One is runaway steam if the pipes are too small and the REAL load is greater than what you think. First, on every process equipment, one must use a safety factor of 3X for start-up loads. What you are using as a load is steady state. I have seen many instances when the engineer used the steady state thus causing all sorts of problems.



I had one plant that nearly went bust after 6 months of trial and error when the engineer sized the boiler as one would size a hydraulic load. We instructed the owner on starting one process at a time so that each would reach steady state before starting a new process or other equipment. We also separated the higher pressure returns from the lower pressure returns. Insulation IS absolutely necessary! A minimum of 2 inches on supply and 1 inch on return for low pressure steam!



Here is one of my brewery jobs with 27 fermenters:

J Diamond

The Plan

First, let me say how much I appreciate everyone's enthusiastic and informative responses.



Our plan moving forward is to keep the existing boiler, relocate it to sit right next to the hot liquor tank and brewkettle (i.e. the loads), insulate the steam lines, install a modulating burner and control, and a controller that will more easily allow the user to select operating pressure between 15 psi and 35 psi.



The idea here is that we'll save energy and extend the equipment's lifespan by modulating the burner, and also have the benefit of a system which can produce pressure > 15 psi for days when something goes wrong and we need to heat a bunch of water in a hurry. For example, a couple weeks ago, someone forgot to turn the boiler on the night before a brew day. So, that morning we kicked the boiler up to 35 psi, and were able to heat 700 gallons of water to 175 degF in just a few hours.



I still wonder if the steam pipe inlet to the loads is properly sized for 35 psi. How can I determine this? Is there a standard or a chart that tells me what this should be? I imagine this must be the case...

Henry

Steam pipe sizing

You can get a very good steam manual from Armstrong International.

www.armstrong-intl.com

Their manual has steam tables, explains which trap for what and how it works, has an excellent section on jacket kettles (which is a real can of worms for most) and has the pipe sizing for both supply and returns at different pressure.

SteamAE

Operating pressures

My first comment is regarding operating pressures. You mention that the boiler cycles a lot. A modulating burner WILL help that. However, it is tough to match the actual load of a user with the output of the boiler. Though slightly less efficient as far as energy savings,  the best way to reduce cycling, always have steam at hand, and get a constant flow of steam to the user, is operating the boiler at a higher pressure than what the user requires and utilize a pressure regulating valve at the user. This allows the boiler and all the steam piping to act as a steam energy capacitor, allowing X number of pounds per hour at X psig, consistently. If the boiler is sitting there charged up to 50 psig... you call pull 15 psig steam from it for a decent amount of time before the burner will even have to kick on. If the boiler and piping were charged to a greater pressure, the burner would stay off for even longer. Also, this method would get you around the expense of a retrofitting to a modulating burner. For example, you would set your pressure controls to turn burner on at 25-35 psig and off at 50-60 psig. Set your PRV at 15 psig and run. Just make sure everything in the steam piping system is rated at the highest operating pressure the system could see. There is suppose to be a safety valve in line, set at the maximum pressure the system can safely see. This method of operation is typically seen in very critical processes. Your process may not require this method... but its food for thought. On a side note, tts good to see the boiler you have has low pressure sized fittings... and I like to see its a Fulton boiler. As long as the water chemistry is maintained within the recommended guidelines on the side of the unit, it will last forever. Personally, it is the most rugged, robust, and reliable steam boiler on the market.

SteamAE

differntial, insulation, NPSH, and design pressure

Increase your operating differential. Turning the boiler on at 25 psig and off at 30 psig seems a bit narrow banded. See the operating manual of the boiler and find the operating instructions of the operating pressure control. You should be able to increase the differential of when the unit turns on and off.



Insulating the supply lines is must. As you warm up and keep warm, all that piping, steam is condensing and you are loosing your temperature/pressure.



Be careful insulating the condensate return lines however. If you have high cold water make-up rate, its not a bad idea. But if you are getting all the condensate back from the system, you may overheat your feedwater tank and cause your pumps to cavitate. Check the temperature of your feedwater tank. If it averages 180-190, you shouldn't have a problem. Its when the water gets up to 200 deg F or higher when NPSHA approaches the limits of the pumps NPSHR. (Net positive suction head available vs. required.) When a pump cavitates, it sounds like its pumping marbles. I can provide an atmosphere NPSHA at various temperatures and tank elevations if you like.



You can get a 15 psig boiler with a modulating burner.. however the boiler you have (high pressure with low pressure fittings) is much more universal. Purchasing a 15 psig unit will handcuff you to only being able to operate the boiler at 12 psig MAX. (15 psig boilers cannot operate at 15 psig, as the safety valve will begin to weep. Just like 150 psig boilers should only operate up to about 125 psig.)

SteamAE

Steam velocities... very important.

Armstrong is good source.

Spirax Sarco (http://www.spiraxsarco.com/us/) is another very good source. They have (2) books available for free (that they previously charged for) that I reference almost daily. "Steam utilization" and "Hookups".



Attached is (2) steam velocities charts. One from spirax sarco that has some dialogue with reasoning. The other from Watson Mcdaniel that takes up a whole page as is easier to use.