MCQOPTIONS
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				| 1. | 
                                    A device in which some portion of waste heat of flue gases is recovered to heat the air before it passes to the furnace for combustion purpose, is known as$? | 
                            
| A. | Superheater | 
| B. | Air-preheater | 
| C. | Economizer | 
| D. | Injector | 
| Answer» C. Economizer | |