Need help installing 2nd boiler for superheated steam drying system 1

[jabroni133]

Hey guys,

Let me just start by saying that boilers are not my specialty, so please excuse any ridiculous comments or statements that I make in this post. I'm a biosystems engineering student and I'm working as a summer research assistant to a PhD candidate. We're operating a superheated steam drying system which we use to dry waste biomass which can then be pelleted and used as a fuel source. The system is currently being run by a single boiler which provides steam at 54 lbs/hr. The superheated steam drying system runs well until the boiler runs low on water, at which point a floating ball pump is activated and extra water is pumped in and heated up to create more steam. During this time the velocity of the steam in the system drops which affects the quality of the data we are collecting (our goal is to model the drying of biomass). A second boiler has been purchased to hopefully alleviate this problem but we are having issues determining the best method to install it. We are concerned that just directly adding the output of the second boiler to the output of the first boiler will help lengthen the time before filling occurs but won’t actually eliminate the problem of eventually filling the boiler(s). Is there a method to install the second boiler that ensures that each boiler can support the other while they are filling? Ideally without installing some sort of computerized control system.

Any suggestions would be greatly appreciated.

Thanks in advance!

 

[chicopee]

Are you sure that the boiler is only providing 54lbs/hr of steam?

 

[StoneCold]

You could probably get away with one boiler if you would have changed the boiler feed to continuous instead of on a float system.
You can tie both boilers into a common header with pressure control on the firing rate to control the header pressure at a constant value.
Are you sure your are creating superheated steam? Does your boiler have a boiling section and a super heater section?
I am doubtful due to the small size but I could be very wrong.

Regards
StoneCold

 

[GenB]

You just buy the boilers without any help by the mfrs. On small systems the boiler should be sized several times bigger than the expected steam consumption.
I think you should contact the boilers mfrs for a piping diagram so you can doit right. Even a small boiler can create catastrophes so very careful.
If you seek further help here, provide pressure, type of boiler, fuel or power.
Gen blr

 

[jabroni133]

Thanks for the responses.

GenB: We're running a Sussman electric boiler, model ES18, with an output set at 60 psi. I'm not too sure how the talks with the manufacturers went, this is my first summer working for this professor and he's had the new boiler, which is a Sussman MBA18 electric boiler, sitting in his lab for the last 12 months, but the original boiler has been in use for a few years with no issues except the decreased steam velocity during filling. As well, when we're running experiment the boiler is in operation for 5-7 hours but then we usually don't use it for a few days.

StoneCold: The boiler itself is only used to provide saturated steam which is then passed through a pressure reducer and then a superheater to create the superheated steam. Once the steam is superheated we control the outflow pressure to be between 0.1 and 0.5 psi. Personally I would've set up a continuous feed system as opposed to the float system but what's done is done and my supervisor doesn't want to alter anything on the original boiler, just add a new one. I like the idea of using pressure control on the firing rate of the boilers, in my untrained mind this seems like it would help our situation. I'll bring it up to my supervisor and let you know if we go that route.

Chicopee: I just checked the user manual at the steam output for our boiler is 54.2 lbs/hr.

Sorry for the delay in getting back to this, I was sick most of this week. Now that I'm feeling better I'm going to stay on top of this.

Thanks!