×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Question About Water Tube Boilers
3

Question About Water Tube Boilers

Question About Water Tube Boilers

(OP)
Hello,

I am a recent graduate and I just started my first job at a specialty chemical plant.  One of my 1st assignments is to monitor our natural gas consumption.  

In order to calculate the efficiency of a boiler it is simply the Steam Energy Produced/Natural Gas Energy Consumed correct?

Well I was able to collect the data that I need from our natural gas supplier for the energy consumption.  However, this plant is only 1 year old and there is not enough instrumentation to collect the data that I need for the amount of steam produced.

My questions are the following:  

1.)  What steps should I take in order to get an accurate estimate of the amount of steam produced?

2.)  Once I calculate the correct boiler efficiency, what calculations do I need to make as far as air flow rate?

Thank you  

RE: Question About Water Tube Boilers

ChemicalAg,

1. If you do not have a steam flow meter on the boiler output I would install one with a totalizer.  I do not know of a way to accurately estimate steam production.  Steam demand can very significantly in the course of a day.  Vortex or orifice meters are fairly inexpensive.

There are other factors that can effect efficiency like boiler feedwater temperature, percent of condensate recovered, economizer performance, etc.

I recommend checking the DOE Industrial Technologies Program for steam best practices.

http://www1.eere.energy.gov/industry/bestpractices/steam.html

The attached .pdf has a way to benchmark the cost of steam production.

Good luck.

RE: Question About Water Tube Boilers

Do you measure your boiler feedwater flow anywhere?

rmw

RE: Question About Water Tube Boilers

The usual  means of calculating efficiency requires the accurate measurement of only one flow. Normally that flow is the feedwater flow. But if your site only has accurate measurement of the fuel gas flow, then you could modify the procedure to use that flow as the ultimate indicator of unit load.

Other data that would be needed is feedwater inlet temperature , drum pressure, blowdown flowrate ( or isolate it for the test), steam outlet pressure and temperature, and stack O2 and/or CO2 level, inlet air temp ,and stack  exhaust temp.

refer to the asme power test code PTC 4 or summary description in the B&W Steam book.  

RE: Question About Water Tube Boilers

Hi RMW,
i also have the same problem. I have the data for boiler feedwater. How should i proceed?

THanks!

RE: Question About Water Tube Boilers

Either of the two referemces mentioned by davefitz will work.  Your water flow in is an indicator of the steam flow out and with that information and what you know about the steam and flue gas out you can do the calculations.  Be sure to account for any boiler blowdown as that does not become 'steam out', but it is "BTU's out".

rmw

RE: Question About Water Tube Boilers

Hi,

For a full calculation using different methods, see EN 12952-15 Water-tube boilers and auxiliary installations. Acceptance tests

br
Drex

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources