Changing Boiler Fuel Type

It sounds like you have all the data you need to produce a fairly accurate estimate except for the price of oil and gas.

If you want to go a step further you could also take into account the cost of changing over the transporting, handling, storage and maintenance from oil to gas.

Do you get any additional government (environmental charges or rebates) or maintenance benefits from switching to a cleaner fuel? Don't forget to check as you may find this reduces the overall payback period.

the unit cost of light oil in my country is 0.164 US$/liter and for natural gas is US$ 0.0522US$/m3

do not amaze I believe these prices will increase soon; however let us work on the existing.

thanks

Then all the information needed to effect the calculation is already to hand, assuming that by <...kW...> in the calorific values what was meant is actually kWh.

yes you are true the calorific value in KWh

Go on, then. Get the pocket calculator out...

Dear Mr. esmat,

The Calorific Value will be in BTU/Lb. (or) CHU/LB. (or) K.CAL/Kg. (or) KJoules/Kg. (or) W/gm. (or) KW/Kg. but not KWH.

DHAYANANDHAN.S

W/g and kW/kg would not qualify as comprehensible units of calorific value as they both have the dimension [time]^-1.

please check this site to see the relationship between the KWHR as energy unit and the KJ also

http://www.efunda.com/units/convert_units.cfm?From=203

dear esmat,

It is very simple. You have to ESTIMATE THE ALTERNATE FUEL REQUIRED - UNDER IDENTICAL OPERATING CONDITIONS, and once QUANTIFIED, MULTIPLY BY UNIT COST OF THE FUEL, this one You yourself can calculate.

While deriving the QUANTITY OF ALTERNATE FUEL, the COMBUSTION EFFICIENCY, Perhaps AIR-FUEL RATIO, NON-COMBUSTIBLES will come in to Picture.

The NEED is that "EQUIVALENT AMOUNT OFHEAT IS TO BE RELEASED, BY THE ALTERNATIVE FUEL, IN THE FURNACE - FOR IDENTICAL LOAD/OPERATING CONDITIONS" of the Boiler, then only we can estimate the fuel cost.

As other CR4 MEMBER has pointed out the Impact on the Investment of Equipment is also to be accounted, for arriving the OVER-ALL BENIFIT.

If you want, I will work out and post the message, for which you have to furnish the following, to derive the SAME HEAT RELEASE IN THE FURNACE, for both fuels.

1. FUEL ANALYSIS. 2. MOISTURE CONTENT if any in the FUEL. 3.ASH CONTENT and NON-COMBUSTIBLES. 4. EXCESS AIR USED or PERMISSIBLE.

DHAYANANDHAN.S

I do not have the fuel analysis however I am sure of the following info:-

light oil used has a calorific value of 11.22 KWh/liter and the natural gas calorific value is 10.73 kwhr/m3. and my boilers gross efficiency as per last audi was 85%.

my question is how to calculate the energy saved due to replacing my old burner by the new one working mainly with natural gas.

finally the government will not pay my property any debat all what I make use is the cost reduction of the each unit of fuel type as indicated previously

As pointed out by several others already, you are not comparing correctly the two fuels.

Where is it given that a cubic meter of gas produces the same amount of heat as a liter of oil? It could be more or even less.....

You need to work out the amount of heat (BTUs?) per Dollar of gas and the per Dollar of oil type you are using!!!!

Then you can properly compare one with the other.....till then, you are only guessing!!!

Though gas usually brings lower maintenance costs which may affect the comparison, as it brings less deposit with it and a simpler burner that does not need a pump. Not to forget that correctly formulated gas will still flow freely in even very cold weather!!!!!

Dear Mr. Andy,

Your views concur with my views (Refer Post No.2), I have referred ""EQUIVALENT AMOUNT OF HEAT IS TO BE RELEASED, BY THE ALTERNATIVE FUEL, IN THE FURNACE - FOR IDENTICAL LOAD/OPERATING CONDITIONS."

This means EQUAL AMOUNT OF HEAT is to be RELEASED in the Furnace, for IDENTICAL LOAD CONDITIONS,for which, the quantity of the 2nd Fuel will vary and cost is known and can be compared.

DHAYANANDHAN.S

"my question is how to calculate the energy saved due to replacing my old burner by the new one working mainly with natural gas."

That is a good question!

To answer this you need to separate boiler efficiency and combustion efficiency, and review the numbers separately. You or your boiler tech needs to perform a combustion analysis to determine how effectively the existing burner is extracting energy from the fuel. Determine what repairs, cleaning or adjustments are needed to optimize the performance. Review the proposed new burners to determine their effectiveness in extracting energy from the fuel.

Generally, natural gas is easier to burn than fuel oil, and might be slightly better performance.

Good luck with your project.

your comment is excellent.

please send me your e-mail and I can send my last boiler analysis to calculate the efficiency of the old burner and then we can work on the new burner analysis.

if possible we can calculate the combustion efficiency based on the report I will send you

Doing a quick calculation

2 boiler on oil x 3035kW/boiler x 8/24 hr /day x 0.164 $/litre x 100/85 efficiency / 11.22kWhr/litre = $34.79/day on oil

2 boiler on gas x 3035kW/boiler x 8/24 hr /day x 0.0522 $/m³ x100/85 efficiency / 10.73kWhr/m³ = $11.58/day on gas

Savings $23.21/day.

Capital cost $215,000.

Bank interest at 4% on $215,000 = $23.56/day

Payback NEVER

(but if you can get 4% on this deal I want to be with your bank)

That also assumes that the capital costs include changes needed to storage facilities, safety and maintenance equipment, as well as retraining of personnel.

Can you point me to a link which says that a cubic meter of gas supplies the same energy as a liter of oil. It appears to be missing from this blog as far as I can tell....

I did find these websites which understand the problems of calculation, it could possibly help the OP to get it right. (The second two links have built in calculators for which fuel is best for you)

One thing that is needed that has not been supplied, is the exact types of oil and gas, or even better, the calorific value of each in a specified amount.....

http://askville.amazon.com/BTUs-gallon-oil/AnswerViewer.do?requestId=5286513

http://www.fpl.fs.fed.us/documnts/techline/fuel-value-calculator.pdf

http://nepacrossroads.com/fuel-comparison-calculator.php

I took the values given in the original post, made the same assumption as post 5 that kW should read kWh and did a simplified calculation to show that with the figures as stated this project is a non starter. I did not question or verify the stated figures.

I also did not question that these boilers are running 8 hours per day which is very odd if you have to run 2 industrial sized boilers in tandem. I did not include a correction for the fact that any boilers only running 8 hours/day probably also only run 5 days/week and 45 weeks/year. If I asked my bank manager only to charge interest on capital only while a plant was running rather than 24-7-52, I suspect that his response might be unprintable in a child friendly forum like CR4.

I did not factor in a possible grant/investment tax windfall or that governments normally take 6-12 months to pay out such bounty. Nor did I factor in maintenance costs, training, lost of utility while the plant is modified and many other variables.

I suspect that this is a homework exercise. If it is, the teacher/lecturer/professor who set it should be castigated for including a totally unrealistic capital spend. The capital spend:returns ratio is so low that this would never have passed the first hurdle in a real commercial/industrial environment.

You could be right about the Homework, let us wait and observe!

Certainly there is a lot of VERY important infos missing that need to be known and factored in before anyone can make a stab at finding out which fuel would be best!!!

I certainly have the feeling that the difference is a LOT smaller than the OP imagines!!!