Do the boiler and thermic fluid heater tests in the Bureau of Energy Efficiency Vapi 5 lakh kilocalorie gasifier report add up?

Three of four do. The Bureau of Energy Efficiency (BEE) Vapi report prints 62.2, 48.9, 61.65 and 64.6% for old oil-fired units. The last, a thermic fluid heater, reaches 64.6% only if the oil density is read as 0.62, not the 0.8 printed, which would give 83.3%. That is our check.

Two machines, in plain words

A boiler boils water into steam. A thermic fluid heater warms oil in a closed loop, and the hot oil carries heat to the dryers, the way the hot water loop of a radiator system carries heat to rooms. The report calls it a Thermopac; we read that as a brand name. It proposes replacing the oil these machines burn with gas made from wood in a gasifier.

Efficiency is how much of the fuel's heat reaches the job. Think of carrying water in a leaky bucket: it is the share that arrives.

The four tests

• Dilip Chemicals boiler: 20 kilograms an hour x 10,000 kilocalories (kcal) per kilogram = 200,000 kcal in. Steam 200 x 622 = 124,400 out. 62.2%. The steam is given per day and the fuel per hour, with 3 operating hours, so the units are mixed.
• Dilip Chemicals heater: light diesel oil (LDO) 21 kilograms an hour x 10,000 = 210,000 in. Oil flow 8,000 litres x 0.9 = 7,200 kilograms an hour x 0.62 x 29 degrees of rise = 129,456 out. 61.65%. This one ties.
• Sterling Pigments 'baby boiler': 30 x 10,000 = 300,000 in. Steam 250 x 586.24 (656.24 minus 70) = 146,560 out. 48.9%. This one ties.
• Chemodist Industries heater: 50 x 10,000 = 500,000 in. Flow 60,000 litres an hour, density 0.8, specific heat 0.62, rise 14 degrees. Printed heat out 322,896, so 64.6%.

The one that does not tie

60,000 x 0.8 x 0.62 x 14 = 416,640, which is 83.3% of 500,000. The printed 322,896 equals 60,000 x 0.62 x 0.62 x 14. Our reading: the specific heat of 0.62 was used twice and the density not at all. The report does not say whether the flow, the density or the printed output is the slip.

The flow also stands out: 60,000 litres an hour is 7.5 times the first heater's 8,000. Measure your own flow and temperatures rather than copy either.

Where the 41 kilograms an hour comes from

The gasifier is sized on 41 kilograms of oil an hour, 3 hours a day for 280 days, 840 hours. No tested unit burns 41. Our check: Dilip Chemicals' boiler 20 plus its heater 21 = 41. If so, the saving is one plant's two burners together, not a cluster average. The report does not say.

41 x 10,000 = 410,000 kcal an hour. Wood at 3,500 kcal a kilogram and 75% gasifier efficiency is 410,000 / (3,500 x 0.75) = 156.2 kilograms an hour. 156.2 x 840 = 131.2 tonnes of wood against 34.44 tonnes of oil (41 x 840).

The money and the spec

• Oil 34.44 tonnes x rupees (Rs) 30,000 = Rs 10.33 lakh. Wood 131.2 x 3,500 = Rs 4.59 lakh. Power 6,266 kilowatt hours x Rs 5.7 = Rs 0.36 lakh. Net Rs 5.38 lakh. A lakh is 100,000.
• Cost Rs 15.60 lakh. Payback 15.60 / 5.38 = 2.90 years. Own money Rs 3.90 lakh, loan Rs 11.70 lakh.
• Spec table: model RG-300, rated 600 kilowatts, able to replace up to 50 litres an hour of high speed diesel, wood use 175 kilograms an hour at full output, auxiliary power 10 horsepower.
• Table 1.2 is headed two typical units but lists three: 28,290 kilograms for 60,000 kilograms of product (0.47), 18,033 for 60,000 (0.30) and 96,000 for 240,000 (0.40).

The heater that does not tie

• As printed inputs: 60,000 litres x 0.8 = 48,000 kg an hour
• Heat out: 48,000 x 0.62 x 14 = 416,640 kcal an hour
• Efficiency: 416,640 / 500,000 = 83.3%
• As printed output: 322,896 / 500,000 = 64.6%, and 322,896 = 60,000 x 0.62 x 0.62 x 14

Inputs and the printed output are the report's own. The reading that 0.62 was used twice is ours.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records. Monthly oil bills give kilograms a month, and dividing by run hours gives your hourly figure. Oil flow and temperature readings are taken on site; process sensors can be set up with the Senseible team on request.

• Green loan readiness check
• Thermic fluid heater emissions
• Vapi wood gasifier: size against need
• Vapi reports: wood counted as a cut or zero

Sources: BEE, Detailed project report: bio mass gasifier 5,00,000 kCal/hr, Vapi chemicals and dyes cluster (SAMEEEKSHA)

Last reviewed 2026-11-07. Figures are from the report named above, written in 2010; costs, fuel prices and paybacks are at that year's prices. Check today's prices and a current maker's quote before you rely on the payback.