MCQOPTIONS
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MCQOPTIONS
This section includes 11 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In practical operation of any furnace, zero oxygen percentage or theoretical CO 2 percentage in flue gas is rarely achieved, because of |
| A. | use of non-preheated combustion air. |
| B. | use of pulverised solid fuels. |
| C. | imperfect mixing of fuel & air and infiltration of air. |
| D. | use of excessive positive draft in the furnace. |
| Answer» D. use of excessive positive draft in the furnace. | |
| 2. |
Combustion of furnace oil in a furnace (soaking pit) with preheated combustion air at 400°C results in saving of about __________ percent furnace oil as compared to its combustion with atmospheric air, if the flue gas outlet temperature from the soaking pit is 1200°C. |
| A. | 5 |
| B. | 60 |
| C. | 20 |
| D. | 40 |
| Answer» D. 40 | |
| 3. |
While the fuel fired furnace can be used upto a maximum temperature of about 1700°C, the electric furnace can be used upto a temperature of about __________ °C. |
| A. | 2000 |
| B. | 3000 |
| C. | 4500 |
| D. | 6000 |
| Answer» D. 6000 | |
| 4. |
Presence of SO 2 in furnace gases attacks the ferrous metal by way of |
| A. | accelerating the rate of scaling. |
| B. | causing metal embrittlement. |
| C. | attacking the grain boundaries; particularly severe on low carbon and nickel bearing steels at high temperature. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 5. |
Flue gas outlet temperature from the chimney of any furnace should be ideally about __________ °C. |
| A. | 50 |
| B. | 100 |
| C. | 150 |
| D. | 250 |
| Answer» D. 250 | |
| 6. |
Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above __________ °C, because corrosion prevails at higher temperatures. |
| A. | 350 |
| B. | 750 |
| C. | 1050 |
| D. | 1250 |
| Answer» C. 1050 | |
| 7. |
Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case of complete combustion of |
| A. | furnace oil with air. |
| B. | furnace oil with oxygen. |
| C. | blast furnace gas with air. |
| D. | blast furnace gas with oxygen. |
| Answer» D. blast furnace gas with oxygen. | |
| 8. |
In furnaces operating at very high temperature (say) 1250°C, e.g. soaking pit), the maximum heat transfer takes place by |
| A. | conduction |
| B. | convection |
| C. | radiation |
| D. | can not be predicted. |
| Answer» D. can not be predicted. | |
| 9. |
Acid dew point temperature (ADT) of a flue gas produced by the combustion of a fuel containing 1% sulphur may be about __________ °C. |
| A. | 80 |
| B. | 130 |
| C. | 180 |
| D. | 250 |
| Answer» C. 180 | |
| 10. |
Which of the following is the most suitable for preheating combustion air above 650°C ? |
| A. | Regenerator |
| B. | Metallic recuperator |
| C. | Ceramic recuperator |
| D. | None of these |
| Answer» D. None of these | |
| 11. |
Ceramic recuperators (made of SiC) is economical, only when used for preheating combustion air above __________ °C. |
| A. | 250 |
| B. | 650 |
| C. | 850 |
| D. | 1000 |
| Answer» C. 850 | |