Sugar Industry 3

[MAEC]

Greetings from Guatemala.

I´m a "rookie" mechanical & electrical engineer with some experience in sugar industry, energy and exergy analysys and cogeneration cycles for sugar industry.

I signed up here mostly for learning purposes since i intend to gather some water tube boiler knowledge... i hope I´m at the right place.

Right now I´m doing a plant analysis and balance from the energy, exergy and mass point of view. If someone has any experience on this topic or in huge industrial boilers i´d appreciate if you could contact me so we can share some ideas.

Best Regards

Manuel A. Escamilla

 

[deanc]

http://www.sugartech.co.za/

 

[JStephen]

Also check at

http://www.steamforum.com.

 

[rmw]

What specific information are you seeking? I would assume that as a sugar miller, your boilers burn bagasse?????

Do you steam turbine drive the grinding mills, and use the exhaust for evaporation and pans??????

How much co-generation do you do, and do you use all the steam in your mill, or do you export steam??????

Do you use supplemental fuel, or is it all bagasse???

How huge are these "huge" industrial boilers of yours?

This should do for starters.

rmw

 

[MAEC]

rmw:

Thank you for your interest. By huge boilers i believe i got out of hand there... but lets say from 4.5 M#/hr and up, bagasse or charcoal fired... I am so interested in this bagasse fired boiler at cogen india... it is quite big!! they have it for power generation purposes only.

Yes, my boilers do run on bagasse... right now i have 3 mills with turbines and the other one with both an electric motor and a turbine...´we are doing some tests so we can motorize the whole tandem soon. We also have turbo generators. The exhaust steam is indeed used in the evap and pan stages. We make an extraction from the evap to the primary and secondary juice heaters.

The thing about this mills is that my family assembled it back in 1863... it is one of the oldest mills on the continent!! We are concearned about CAFTA so the first step on our rezising is my energy analysis. The steam is limited... we have all the exhaust we need but the problem is with high pressure steam since we had to shut down two boilers and we are running now only with one!!!! This one is 2 years old so it is quite efficient, and it is supplying exactly the ammount of steam needed.

I do not use supplemental fuel as you might be thinking... bunker or gas... my boiler is a weird mix of dutch oven and fuel cell instead of traveling grate... it is quite good when it comes to energy reservoir when milling is irregular...

Finally, the especific info i need for now is just on plant balance, energy balance and exergy balance...also something about the ostward graphs... like a spreadsheet or something to make an especific one for bagasse, because i need CO levels and i have no CO analyzer...

I´m quite excited about this forum because it is quite hard to gain knowledge on this especific subjects ( energy, exergy, boilers, turbines, heat transfer equipments.. power gen) on a third world country especially because of professional envy which is quite common here... right now i am reviewing my thermodynamic basics... I´m buying this advanced thermodynamics for engineers book so i can give a step forward later... and paralel to that i read whatever i think it´s good in these forums... so as you can see it is quite an honor for me to have your reply.

Thanks for the time and lets keep in touch

Manuel

 

[rmw]

So, if you motorize your tandem, are you going to let down all your steam through the generator turbines?

Sugars has a software, but it is quite expensive.

http://www.sugarsonline.com/

I often use the freeware found in

http://www.sugartech.co.za

for simple evaporator station sizing, etc. You might find some useful information there.

And, for some real good help with heat transfer, I use the information found at

http://www.processassociates.com

Look under their 'tools' section.

How much electricty generation capacity do you have?

Do you extract all generator turbine steam to exhaust, or do you do any condensing?

Sounds like you have a wonderful situation. Most mills I see either are short on boiler capacity, or are short on exhaust and have to do a lot of let down through pressure reducing stations and therefore get no useful work from the steam.

Your fuel cell/gassifier dutch oven style of furnace should be perfect for wet bagasse. How do you de ash the cells?

Are all your evaporators roberts type, or have you modernized those yet?

rmw

 

[MAEC]

RMW

Thank you for the links... i have seen the sugartech software but i have to say i found some discrepancies in the calculations... i think they use the simple method for calculations which does not involve water sucrose solution's enthalpy nor increase in boiling point inside the tubes nor irreversibilities. It is a good and fast aproximation i have to say and a good tool for quick analysis.

Yes, by motorizing the whole tandem I will redirect steam to the turbos... I have the capacity to generate just about 4 or 5 MW... and I think i´m exagerating a bit. The mill is small... that´s why we are looking to enlarge it.

I also have some 0.7MW backup that uses diesel... way too expensive!!!

I do not condense any vapor. I have exactly the right ammount... what I have to do sometimes is do let some of it escape to the atmosphere for pressure regulation.

I don´t have a gassifier... it is a boiler! The thing is the designer used this combination of types of boilers just to increase energy reservoir when mills are stuck. It consists on 4 cilindrical cells on the lowest part of the boiler which ends in the furnace (all four of them)... it has water walls, superheater, air heater, scrubber... what we don´t have is an economizer... i want to make one... do you know where could i find info on that or a software perhaps. I downloaded this software FireCAD but it isn´t that good.

All my equipment is old. Yes they are roberts but I have to say we change parts often... to keep good operation. We are not thinking about automated equipment at the time. We are automating just some few things like the boiler and the exhaust steam pressure control.

I´m assuming you are a sugar engineer or at least work on a sugar mill... am i right? I will post some other questions later when I finish my new equipment balance... perhaps next week. What procedure do you use to balance evaporators? Ever seen the Baloh & Wittwer Book??