CNG Cylinder
80 Ltr. Capacity (20Kg/Cm2)
1Kg/Cm2 = 7M3/hr
248kg/Cm2 filling pressure.

Have a gas engine consuming 350 SCM of Natural Gas per hour to produce 1200 KWH.

In PNG (pipe line Natural Gas) @ 34/- the fuel cost per unit shall be (350*34)/ 1200 = 9.91/-

In case we fill the CNG to 3nos. bottles of capacity 20 Kg/Cm2 each, then flow shall be 20*3*7 = 420 M3/Hr cost of each Kg of CNG is 34/-.

Now the cost of 3 CNG bottles will be 20*3*34 = 2040/-

If we run the Gas Generator for 1 hour the the fuel cost per unit shall be 2040/1200 = 1.7/- per unit.

How come such a huge difference while we operate on Pipe line Natural Gas & CNG.

Pl. correct.

Thanks,
Anil Nalawade

 

Dear Anil,
The mass of gas in a cylinder would be in kg and not kg/cm2. If you have decided to calculate with volume(scm) in case of PNG, then calculate using volume also in case of cascade rather than mass as you have done.

Please recalculate. Due to the regulatory climate in India which distorts pricing, the difference would be about 30% less in case of PNG as volume in both cases would come to be the same.

There is something wrong with the quantity of cylinders. One 80L cylinder pressurized to 248 kg/cm2 is equal to just 20 SCM. Three cylinders would be sufficient for just 10 minutes of operation.

Regards,
Tomy Zacharia