Boiler Efficiency

Tighten the envelope, insulate, insulate, insulate.

You need maintain about 900°F flue temperature.

you need to be concerned about corrosion due to sulphur in fuel. you should know the acid dew point. That would be the basis of knowing safe boiler exit gas temperature. Based on that you can plan for heat recovery by economizer or air heater and reduce fuel consumption.

Very Good advice.

good comments from the prior posts.

included is a hyperlink for some reading material also

http://www1.eere.energy.gov/industry/bestpractices/pdfs/tech_brief_true_cost.pdf

and if you need help on regeneration, just post or send me an email

phoenix911

Dear all,

I thankyou all for your valuable response,

if we are using a economiser in stack line and circulating the feed water through it we can gain the heat from exhaust line. The feed water is already at about 70 and under pressure, so the total feed water loop including economiser temp is above 70deg, are there still any chances for sulphur attaining it dewpoint??

What would be the cost saving in terms fuel, to raise the temp of feed water by 1 deg per lit...for 5 TPH boiler.any cost saving calculations...so that it can be proved before we can get it sanctioned to install a economiser.

The sulfur dewpoint could as high as 160 to 170 °C. It will depend on Sulfur quantity in fuel.

Give me fuel rate.Number of hours and Number of days boiler is running this will help in calculating payback.

Regards & Thanks

Rahul Khandelwal

+971505578890

Dear B Madhu S Rao,

Certainly you can use Economiser to heat the Condensate.

1. What is the Sulphur Content of the oil used, Based on that we have to calculate the partial pressure of SO2 gas formed during COMBUSTION and find the Dew Point of the Sulphur Vapour asper the DALTON's LAW OF PARTIAL PRESSURE of SO2 and keep safe margin of 50 to 60 Deg.C above the Dew Point to avoid acidic corrosion. What is the Stack Gas Temp. leaving the Chimney and What is the Excess Air % used.?

2. Why your Condensate temp. is 65 to 70 Deg.C. Is that condensate extracted under a vaccuum system, if so what is the Vac.? If the condnsate is obtained at atmospheric pressure, or more, hen the condensate Temp. should be 100 Deg.C or more.

3. Air Pre-Heater also can be installed, and recover the heat from the flue gas leaving the Boiler, subject to the Dew Point problem, as explained above.

4. You can think of recovering the Heat from the Blow-Down Water going out of the Boiler, by the condensate returning to the Boiler, by installing a Heat Exchanger.

5. You have to contain the Radiation Losses by proper Insulation, contain or control the formation of CO, i.e. CARBON MONO-OXIDE on the COMBUSTION FRONT.

DHAYANANDHAN.S