Steam and power cost

Pasting my working on Gas. Change to calorific value & rate for coal and make your own calculations:

Electricity demand: = 2700 Kw = 2.7 MW

1 Kw = 6 lbs/hr = 2700 x 6 = 16200 lbs/hr Steam/7.3 Tph

Steam 16,200 lbs/hr = 16.2 mmBtu/hr

Heat Input to Boiler: = 16.2 mmBtu/hr

---------------- = 23 mmBtu/hr

70% Waste Heat efficiency

Exhaust: = 23 – 16.2 = 6.9 mmBtu

Electrical output:

(based on typical

100 Kw/600,000 Btu) = 16.2 mmBtu

-------------- x 100 Kw = 2700 Kw

0.6 mmBtu/hr

Equivalent Btus': = 2700 Kw x 3413 Btu/Kw = 9.2 mmBtu/hr

Total Energy: = 9.2 + 16.2 + 6.9 = 32.3 mmBtu/hr (Gas at Generator0

Annual Cost of Operation: = 32.3 mmBtu/hr x 8640 hrs x Rs.265/mmBtu

= Rs. 73,954,000/year

Avoided Cost of Electricity purchased : (Gas Generators)

= 2700 Kw x 8640 hrs x Rs.3.5 Kw/hr

= Rs. 81,648,000/ year.

Avoided Cost of Steam: = 16.2 mmBtu/hr x 8640 hrs

---------------------------- x Rs.265/mmBtu

80% Boiler eff..

= Rs. 46,364,400/year

Annual Saving: = Rs.81,648,000 + Rs. 46,364,400.00 – Rs. 73,954,000

= Rs. 54,058,000/year

I thank you for your reply but the calculations appear to be based on overall steam input but I require an emperical formula for different steam extracions from the double extraction cum condensing TG.Hope to receive your reply.

Regards,

Vasu

You've to send this inquiry to manufacturers of Waste Heat recovery Boilers for steam/hot water/thermo oil heaters from waste exhaust to answer your question.

They will have charts with graphs to indicate different steam extractions.

Try www.garioninaval.com

Thanq.