Correct viscosity of furnace oil at the burner tip for proper atomisation is about 25 centistokes. To reduce the viscosity of high viscosity furnace oil (250 centistokes) to the correct atomisation viscosity (i.e. 25 cst), it should be preheated to about ______________°C?

Related Mcqs:

1. Furnace oil consumption in a furnace for a given duty employing preheated combination air (at 300°) may be reduced by about ______________ percent as compared to the use of atmospheric combustion air?

   A. 5
   B. 10
   C. 20
   D. 35

2. Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the___________________?

   A. Requirement of large volume combustion chamber
   B. Risk of explosion
   C. Chances of clinker formation
   D. Incomplete combustion of coal

3. Bunsen burner is an example of a/an _____________ burner?

   A. Inside mixing/premix type
   B. Outside mixing/diffusion flame/nozzle mix type
   C. Rotary cup
   D. Submerged combustion

4. Use of preheated air for combustion of fuel in the furnace, increases the___________________?

   A. Scale losses of the furnace stock
   B. Calorific value of the fuel
   C. Flame temperature
   D. None of these

5. Atomising steam to fuel oil ratio in a burner should be around__________________?

   A. 0.5
   B. 1.5
   C. 2.5
   D. 3.5

6. Optimum preheating temperature for pitch creosote mixture (PCM) which is also termed as C.T.F-200, before atomisation through burners is_________________?

   A. 200 °F
   B. 200 °C
   C. 200 °K
   D. 200 °R

7. Which of the following is not increased by using preheated combustion air in place of ordinary air at room temperature ?

   A. Calorific value of the fuel
   B. Flame temperature achieved
   C. Speed of combustion of fuel
   D. Heat transfer rate to the stock in the furnace

8. Fuel gases containing hydrocarbons (e.g. coke oven gas) are not preheated before burning, mainly because __________________?

   A. The hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot
   B. It reduces its calorific value tremendously
   C. It reduces its flame temperature tremendously
   D. There are chances of explosion during preheating

9. The main function of primary air in pulverised coal fired burner is to_________________?

   A. Burn CO to CO2
   B. Dry and transport the coal
   C. Have proper combustion by supplying it around the burner
   D. Preheat the tertiary air used for complete combustion of CO to CO2

10. Turndown ratio of a gas burner is equal to the __________________ ?

    A. Maximum to minimum heat input ratio
    B. Maximum to minimum permissible gas flow rate
    C. Both A. & B.
    D. Minimum to maximum heat input ratio