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Steam Line Questions


mikeg

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Hi Everyone,

We're getting close to putting in our steam lines, which means I need to finalize the engineering on the steam lines. I think the only question that I have left is if I need to pump the condensate up to my main return line. I'm hoping people can weigh in on this and give us a little insight.

If I'm not missing anything, I think the main details needed to answer this question are:

1) The still's jacket is rated only to low pressure (<15psi)

2) The power to the still will be adjusted by a gate valve on the steam line.

3) We'll have a strainer, steam trap, and check valve on the condensate line out of the still

4) And then immediately there will be a 8' to 9' rise to the main condensate line running back to the condensate return tank that feeds the boiler

Other info on the system:

The still is 250 gallon

The boiler is a 30HP Parker that we'll probably run around 30 or 40 psi with a 15psi pressure regulator in-front of the still and mash cooker.

We plan to branch off a main steam pipe that will run about 30' sloping away from the boiler, with a trap at the end to run the main condensate line sloping back to the boiler.

My thinking on it is that if the still's jacket is at 15 psi, that is more than enough pressure to push the condensate up 9'. But with regulating the power to the still with the gate valve, I can't be positive that the pressure will always be 15 psi, right? By my calculations, I only need about 4.4 psi to push it up. Can I be sure that there will always be 4.4psi on the back?

Another general question is, if this rise is fine, are we ok with water hammer? What to do? Would an inverted bucket and check valve ok with this?

The easy solution is to put in a Pressure Motive Pump (PMP). I'd like to get by without it though because of $$ and also because I would need to buy 2 PMPs, one for the still, and one for the mash cooker because those pieces of equipment are spaced out and I can't run a condensate line between them.

I can supply drawings if anyone wants to see the plan. Thanks in advance for any and all comments or thoughts.

Cheers,

Mike

ps.

I also assume that all the info I glean from here should be double checked with experts and I will take any suggestions at my own risk.

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Hi Mike.

I have a very similar setup and I don't need a condensate pump. I have a 280 gallon 15 psi still and push up about 11ft to my ceiling via 1" black pipe and then about 40 ft along the ceiling to my condensate tank. I think the required pressure works out to 1 or 2 psi to move the condensate. Toward the end of my run I am using so little steam the gauge is hardly registering, I have an inverted bucket trap and check valve at the still. Sizing your trap is critical, too small and you will water lock very quickly. I sized my trap for a max of 3300lbs/water an hour at 15psi. Found a new one on ebay for $100. I have a little hammer at startup but its steam so its expected. I slope my steam feed TOWARD the boiler so it drains back into the boiler. Also, don't use a gate valve for steam throttling as they will prematurely wear out. A gate or ball used in a steam line should either be wide open or fully closed. For throttling you should really use a globe valve(got a 1" globe rated for steam on Amazon). I grew up in a family of steamfitter/welders/jack-of-all-trades so I had lots of family help.

I also have a 350g steam kettle running at 40 psi as my mashtun and have it setup the same. I've been running about 7 months with no issues. I also have a 15psi steam tap that I use to steam flush and reactivate my granular charcoal spirit filter. Makes filter maintenance very easy and saves money on charcoal. I would suggest adding some extra T's (or replacing some 90 degree elbows with T's) to allow for future expansion and/or reconfiguration. You never now what you might need an extra steam outlet for.

Also, you should check if your state or town requires a PE certified stamp on any steam drawings. Since your boiler is over 15psi its considered a high pressure system. Most states require it and most insurance require it.

Hope this helps.

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That's great, practical advice from kckadi. The only hair I would split is in the specification of the steam trap. If your jacket is at 15 psi then you do need to specify that the trap can close against this pressure, but when the trap opens to discharge the condensate the pressure drop available to drive the condensate through the trap will be less than 15 psi and this needs to be specified as well. As you have already calculated, you need 4 or 5 psi to lift the condensate back to the top of the tank so you would only have a maximum of 10 psi to drive the condensate through the trap itself. And as kckadi has pointed out, towards the end of the batch the steam valve will likely be throttled and even less pressure will be available for the trap. You probably want to allow around 3 psi for the trap at the rated capacity - this will give you some extra capacity at start up.

Trap manufactures like Spirax have all their technical material available online so it is easy to download a sizing chart to work out the trap size you need. One other potential problem with stop-start operations like this is that when you have finished a batch and the vacuum relief valve on the jacket opens (or you open the manual vent) to prevent the condensing steam in the jacket sucking in the jacket, air will be drawn into the jacket and this needs to be removed at the next start up. You could do a manual venting to do this, but you can specify that the trap should include an air vent to do this automatically. An inverted bucket trap cannot work without such a vent, so it will be included anyway if you select this type.

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Mike,

If you are running over 15 psi on your boiler, you will have to get licensed as a certified boiler operator, or you won't be allowed to turn the thing on. Check with you state and local authorities for more information if you haven't done so already.

Best,

McKee

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All good comments by everyone. I'd like to add that you should also have a pressure relief valve down stream of the pressure regulator set at 15 PSIG. Depending on the state the inspector will want to see this to make sure down stream equipment is protected just in case the regulator fails open (although some may ague regulators will always fail closed, inspectors think otherwise).

And the rule of thumb is that 1 PSI can push water about 2.3 ft vertically.

If your worried about not having enough pressure to push the condensate up into the header you can always put a pressure gauge before the trap.

Spirax Sarco has so much good info on their site:

http://www.spiraxsarco.com/industries/examples/process/jacketed-pans/jacketed-pan-assembly.asp

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Mike,

If you are running over 15 psi on your boiler, you will have to get licensed as a certified boiler operator, or you won't be allowed to turn the thing on. Check with you state and local authorities for more information if you haven't done so already.

Best,

McKee

Only in certain states do you need a certified boiler operator. But I agree, definitely check with you state and local authorities.

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Thanks everyone for the input, this is really helpful!

I spoke to a rep at Watson McDaniel who was really helpful and you guys just confirmed everything he said and then some. The other bits of info he gave me were: put in a strainer in front of each pressure regulator to ensure longevity, and put in a vacuum breaker & air vent at a high point in the jacket. He also suggested ball floats rather than inverted buckets. After reading the literature, it seems like this might be a good choice. Any thoughts?

I plan to run schedule 80 black pipe for the steam and then copper for the condensate return (cleaner, less scaling). Do you have a preferred brazing material? Copper-Phosphor or Bronze?

@kckadi

I'm surprised that you sloped your steam main toward the boiler, from what I understand it's typically sloped forward, but it makes sense to slope it back though. I may have to rethink the slope we plan to put in! Did you still put a drip leg and a vent at the end of it?

Just to confirm my pipe sizing: It looks like our steam main should be sized at 3", with a 1.25" branch to the 15psi regulator to 1.5" to the still (or cooker). Then a 1" condensate rise from the still to a 1.25" condensate return manifold... What do you think? Is this what you have? Spirax's calulators suggests I go smaller with the condensate return: 3/8" from the still into a 1" manifold, which seems small to me but if that's the right size...
http://www.spiraxsarco.com/us/resources/calculators/pipes/single-discharge-line.asp

We are definitely going to plumb in extra T's for growth or wash down stations & steam cleaning... I should probably put in an extra 4 T's.

I'm happy to hear the recommendation on the globe valve. I've been considering it and I think I'll definitely go with those for regulation.

Also, good info on the engineering requirements. I understand the local requirements for registration and what the city does and doesn't need to see but I'll have to check on the insurance part. There could be something there.

@meerkat:

Thanks for the suggestion on Spirax's site. Loads of good info there.

I'll have to look at the required psi for different traps to make sure I have the required psi at the end of the run but I'm not sure how to control this. I'm sizing my pipes so I get 14.7psi at the still so, I think I should be good. Is there something else I should look at?

@jamesbednar

Our still has a vacuum breaker and a pressure release valve on it but no air vent. I assume that the supplied vacuum breaker is explicitly for making sure we don't crush our equipment with a vacuum. In terms of the air vent, I was thinking I would put a strainer on the condensate out before the trap, which could serve as a vent. Any thoughts there?

Thanks for all the great info!

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Mike,

If you are running over 15 psi on your boiler, you will have to get licensed as a certified boiler operator, or you won't be allowed to turn the thing on. Check with you state and local authorities for more information if you haven't done so already.

Best,

McKee

The laws around here are funny about this. To run a high pressure boiler, we need a boiler operator but since our boiler is less than 2MM btu's, it doesn't have to be registered. So, we need an operator for a boiler no one knows about. We're going to have a guy come out to do the initial setup, do initial start-up, tuning, and maintenance. He has suggested that we can throw on some low pressure controls if we want to convert it but that nobody ever really bothers people with such small boilers. So, we're not really concerned about getting busted if we don't have a certified operator. That being said, it seems that the main concern is about liability and insurance.

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All good comments by everyone. I'd like to add that you should also have a pressure relief valve down stream of the pressure regulator set at 15 PSIG. Depending on the state the inspector will want to see this to make sure down stream equipment is protected just in case the regulator fails open (although some may ague regulators will always fail closed, inspectors think otherwise).

And the rule of thumb is that 1 PSI can push water about 2.3 ft vertically.

If your worried about not having enough pressure to push the condensate up into the header you can always put a pressure gauge before the trap.

Spirax Sarco has so much good info on their site:

http://www.spiraxsarco.com/industries/examples/process/jacketed-pans/jacketed-pan-assembly.asp

we definitely plan on having a pressure relief valve down stream from the pressure regulator, don't want to crack open our new still! The still has a 15psi pressure regulator on it but we're going to put in one down stream anyway. We were thinking of going with something like:

T off of steam main

tri-clamp

gate valve

strainer

pressure regulator

pressure relief valve

pressure gauge

globe valve

pressure gauge

tri-clamp

One of the local breweries did something like this where they put in tri-clamps around critical sections so that they could easily remove a section to replace parts.

I wonder if we should have a drip leg in-front of the globe valve or if we should put this section in a section in our vertical drop with the drip leg at the bottom.

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Mike,

Yes, liability and insurance are big ones. But mostly, high pressure boilers are bombs....regardless of overall btu/hr rating. Just be super careful.

Best,

McKee

Absolutely. Thanks for the words of caution.

Cheers,

Mike

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If you slope towards your still you should have a trap before your globe valve, especially if your steam line is a long run.

This Armstrong resource is pretty helpful in addition to the Spirax site:

http://www.carotek.com/assets/pdfs/Steam-Conservation-Guide-101.pdf

Great, thanks for the resource. I'll read through it.

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It is a bit unusual to slope the main back to the boiler. Generally you want the steam and the condensate travelling in the same direction.

I like ball float traps - should be fine in your duty.

It's hard to comment on the pipe sizing because you have not specified the steam flow rate. The sizes you mention would be on the small side for the full capacity of the 30 HP boiler, but I guess you wouldn't be using it all.

It is common to put the vacuum relief valve and the air vent at the high point. I agree with the vacuum relief being there but I have always felt that any air in the jacket is entrained with the steam and condensate and is pulled towards the trap so I prefer to put the air vent in (or in parallel with) the trap. The vent will pass small amounts of steam so it should discharge into the condensate line and be finally released from the condensate return tank.

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Hi Guys,

If run/designed correctly you can use either sloping toward or sloping away, depending upon your pipe layout and where your regulators are(if you are using regulators at all). In my case its a very simple run back to the boiler so the condensate in the feedline will roll back into the boiler after shutdown/cooldown. In this configuration condensate in the feed line is minimized after shutdown. I get very slight hammer at start up and then none. As others have noted if you sloped toward the still you might have to put in an extra trap before the regulator or valve else you might get alot of hammer on startup. Or you could just live with the hammer as long as your opened your globe valve veryyyyy slowly.

For trap size I am using an inverted bucket trap rated for 3300lb@15psi. I think I did the lbs/hr calc based on max BTU the boiler put out, not on the max lbs/hr from it. Oversized? Yes it is but I have also seen specs for a 300g kettle and the manufacturer recommended a 3000lb/hr trap. Going bigger with a trap is fine, going too small will cause an issue I found my trap new on ebay for $100 and it was piped for 1" NPT so no need for bushings or reducers. Be sure to read the manufactures trap spec correctly, its easy to misread the table for the incorrect trap orifice size and undersize the trap.

For my 15hp boiler I'm using 2" black pipe for the steam feed. I currently don't have a vent/relief in mine (forgot to install one at build time) and the only issue I experience is an overfillled boiler as the resulting vacuum after shutdown pulls water from the condensate tank. To prevent this I close the condensate tank return valve installed between the boiler and the tank after i do my blowdown (I also turn off the condensate tank feed pump else it might run). Do I need to install a vacuum relief? Yes I do and I plan on it next time I do boiler maintenance.

Also be very wary of the Black iron fittings you get at the big box stores, I have found them to be junk with bad castings, cross threads, etc. Especially the unions, every dam one of them leaks. Use your local plumbing supply house and spec american malleable iron fittings and machined unions. If you go cheap on this stuff you will probably spend extra time ripping it out after they leak.

I tried to keep my steam setup as KISS (Keep It Simple and Stupid) as possible. Others may disagree with my setup/configuration and thats fine. My system works very well for me and I'm happy with it. Its safe, effective and I have a PE signoff on it.

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Be a trendsetter and insulate your steam lines too. It's amazing how many distilleries I've been to that are running naked. I suppose after paying a small fortune for stainless piping, you might think it a shame to cover it up, but do it.

Yep, we plan on it. I was looking at some 2" insulation here:

http://www.buyinsulationproductstore.com/servlet/the-460/Knauf-Manville-Fiberglass-Pipe/Detail

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  • 2 months later...

Sorry to come late and loud to this, but I'm gonna poop in the punchbowl, so to speak.

We're the do-it-yourselfinist-mother-scratchers there are. If we can save a buck by researching and doing, we're gonna do that.

That said, if this is your first steam application/install, hire a pro and let them do it/show you. Yeah it costs, but this was and is one of the few things I'll bring in a specialist for.

If you screw up your steam power install, your gear wont run right, plus you'll waste time and money. Worse, you risk damaging your expensive and hard-to-find capital equipment: your boiler and process equipment.

We're installing our 4th still here; we've just now decided not to bring in a pro to do the steam line upgrade (we went from 1" to 1.5" steam lines). They will be here to do a final check on the system. make sure our shit is right, and do our annual boiler inspection (as required by the state).

And to follow up on some thoughts: the idea that folks would run a system without a condensate return pump and tank is surprising. I see the comments and I understand the thoughts, but the limits an improperly put together and functioning steam system places on you are amazing and painful. Unless the boiler's make up water tank is below the still and/or right next to the set up, I can see no reason to believe a low pressure system will have the power to properly push condensate back through the system. A 15 psi low pressure system, depending on the owner's settings, can run between 5 to 12 psi. And that's off the pressuretrol in the boiler itself. Will the system have enough energy after the boiler jacket is full of condensate to push all that water back into the make-up tank? I wouldn't think it's the case, but I can be wrong. A 250 gallon jacket half full of water can be like 30-50 gallons of condensate. And that's excluding what's in the condensate return lines. It'd take it a lot of power, in the form of fresh steam, to push it past the bucket trap and over a 10 ft head, hell or even a 5 ft head. remember, after the bucket trap, the condensate line does not use the pressure of the steam in the boiler to move water - the bucket trap keeps this pressure in the boiler. If the water in the lines on the return side of the trap weighs more than the water trying to leave the boiler jacket through the trap, the system just stops and the jacket fills until it cant take more steam.

Hope this helps; I don't mean to troll, just to add some additional thoughts.

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  • 9 months later...
  • 3 weeks later...

This is a great topic, and thanks for all the information everyone has posted. I am in the process of hooking up my steam boiler and am trying to figure out all of the regulators, gauges, valves, and traps that I'll need. I'm using a Burnham 5011B natural gas fired boiler rated for 624,000 BTU/hr steam output. I have a 300 gallon mash cooker and a 300 gallon still. Based on all the information here, I'm confident that I have the correct size boiler for my application.

I believe this boiler is commonly used in basements of homes that have radiant heaters in upper floors. The recommended piping diagram in the manual shows a gravity feed system using a Hartford loop. The normal water line of the boiler is 27" above the floor. The boiler, still tank, and mash cooker are on the same floor level and are only separated by a distance of about 8' with the boiler room wall separating the two. My main question is if anyone knows if I can get by without a condensate pump or a feedwater tank? The condensate outlet for both the mash cooker and still are only about 15" above the floor. By my reckoning, this would mean that the steam trap at the outlet of each tank wouldn't even work and there would water filled in my tank jacket up to the same level as the water in the boiler. Is this correct? It seems like I'd have water hammer in the bottom 9" or so of the steam jacket.

My boiler didn't come with a feedwater tank. Is my solution as simple as buying a feedwater tank and mounting it up high in the boiler room and letting the pressure of the system push the condensate up to it?

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We use an approach similar to what you are thinking, similar size equip. Weil Mclain cast iron commercial, 15hp. Using steam to lift the condensate up about a foot out of the trap to the return line. The condensate return pitches down to the boiler feed tank. We're using a Hoffman 30VBF boiler feed tank/pump combo. We went with this because it sits right on the floor, as opposed to some of the other boiler feed tanks that sit up on a stand (less lift). The feed tank pump returns into the Hartford loop. Remember, when you use a feed tank, the feed tank is sitting at atmospheric and is vented, so you need a pump to push back the condensate into the boiler, under pressure. Also, your steam trim equipment is going to be a little bit different than what would be used for res/com steam heating (water adder and boiler feed trigger will be a different unit). We're only running the condensate a few feet through a block wall into the boiler room, so the runs are short - hence, not necessary to have another condensate pump at the equipment.

I've heard of guys getting the gravity approach to work, but they had boilers in the basements and could return 100% with gravity. Otherwise you are correct, you'll fill the jacket with condensate and stall.

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If your boiler and steam using equipment are all on the same level I can't see how you can get away without a feedwater tank and a boiler feedwater pump. But getting the condensate back to the feedwater tank using the steam pressure will not be a problem over your short distances if you size the steam trap correctly. See my post #3 above. If you will have a minimum pressure of (say) 5 psi in the jacket, and the feedwater tank is at atmospheric pressure then the 5 psi is lost as the pressure drop through the steam trap, as static head to lift the condensate and as friction losses in the return pipe. Over such short distances and with a reasonably sized pipe the friction losses are negligible. So you have 5 psi that will be equal to the sum of the pressure drop through the trap and the static head.

If you want to run your condensate return line 7 ft above the floor to make it safe to walk under then the static head is about 3 psi. You must then specify a steam trap to work at 2 psi at the expected condensate flow rate. At start up you may have a water logged jacket (and want a higher condensate flow rate), but at that stage you can apply the full 15 psi and after subtracting the 3 psi for the static head you have 12 psi to clear the jacket. In fact, your static head will be lower than 3 psi at this point because the condensate level in the return pipe will naturally want to go to the same level as the water in the jacket (even with no steam pressure applied). It is common to specify the steam trap with a capacity of 2x to 3x the average rate to accommodate start up rates, but this can get expensive.

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