Gas and Electricity are the two alternative energy sources available for heating of sealed quench furnaces. This presentation compares the two alternatives and discusses in detail the pros and cons of each.

1. THERMALENGINEERING
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THERMAL ENGINEERING
SYSTEMS.

2. THERMALENGINEERING
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Gas or Electricity
Comparison of performance

3. Introduction
• Gas and Electricity are the two alternative
sources of energy available for heating of
Sealed Quench Furnaces
• This presentation compares the two
alternative sources of energy in terms of cost,
availability, operational advantages and
temperature accuracy
THERMALENGINEERING
SYSTEMS

4. THERMALENGINEERING
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COST
• Efficiency considered :
Electricity- 100%
Gas - 80%
• Calorific value :
One Unit of electricity ,KwHr. = 860 Kcal.
One CU. Mtr. Of PNG = 7500 Kcal
One Kg. Of LPG = 11500 Kcal.

5. THERMALENGINEERING
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Equivalence Ratio
• 1 CU. Mtr. PNG = 7 KwHr.
• 1Kg. LP.Gas = 10.7 KwHr.
Based on the Ruling prices at various locations
Cost benefit can be worked out. In Maharashtra
• 1 CU.Mtr. PNG costs RS. 40/-
• 1 Kg. LPG. Costs Rs. 64/-
• 1 KWHr. Mains Electricity RS. 9.25
• 1 KWHr. ,Diesel generated Electricity RS. 24/-
(1 liter diesel produces 3.5 KWHr. At Max.
efficiency)

6. THERMALENGINEERING
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Cost benefit
• PNG. Over Mains electricity : 60 %
• LP. Gas over Mains electricity : 55 %
• PNG. Over Diesel electricity : 320 %
• LP. Gas Over Diesel electricity : 300 %
(The Use of Diesel generator is inevitable
during Mains power outages)

7. THERMALENGINEERING
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Associated benefits of using Gas
• Investment in D.G. Set is reduced substantially
• Contract Demand with electricity supply
company is smaller minimizing demand
charges
• Deposit amount required by Electricity board
is saved

8. THERMALENGINEERING
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Temperature control
• Time Proportioning action
Time proportioning varies the % on time of
Burner outputs to deliver a variable output
power between 0 and 100%.
• Temperature control is as accurate as with
thyristor controlled electric heating.

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Works like thyristor control with
settable cycle time.

10. THERMALENGINEERING
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Operational advantages
1. Cooling from Carburizing temperature to
hardening temperature is faster. Air blown
in the tubes.
2. Less maintenance and replacement cost for
gas burners. Ni-Crome heaters have a
limited life and are expensive.

11. THERMALENGINEERING
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Availability
• Gas is available readily from number of public
and private companies.
• Electricity has to be obtained only from state
boards . Getting sanction for large loads is
difficult.
• Shortage of electric supply in most parts of
India results in frequent outages.

12. THERMALENGINEERING
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Track Record
• Heat treatment shops using gas fired furnaces
have been more successful commercially and
have grown rapidly.
• The heat treat customers do not have any
preference for electrical heating.

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End OF Presentation
•Thank You