A steam trap survey finds twelve of eighty traps blowing steam. The recommendation is
Answer: C
Fifteen per cent failed is normal for a plant without a survey programme, and the fuel wasted usually repays the work within months. Instituting the routine matters as much as the immediate replacement, since traps fail continually.
Please log in or register to report this question.
A furnace's flue gas oxygen reads 12 per cent. The interpretation is
Answer: D
Twelve per cent oxygen corresponds to well over double the stoichiometric air, so a large mass of nitrogen and surplus oxygen is being heated and discarded. Trimming it toward two or three per cent is usually the single largest saving on such a furnace.
Please log in or register to report this question.
Assertion: the indirect method is preferred for an audit. Reason: it identifies which loss deserves attention.
Answer: A
An audit exists to produce recommendations, and a single efficiency figure supports none, whereas a loss breakdown points straight at the excess air or the blowdown. That diagnostic value is exactly why the extra measurement is worth making.
Please log in or register to report this question.
Assertion: flue gas should be cooled as far as possible in a heat recovery device. Reason: the more heat recovered, the greater the saving.
Answer: B
More recovery is indeed worth more, but below the acid dew point sulphuric acid condenses and destroys the recovery surfaces, so the cooling must stop above it. The reason is sound and the conclusion drawn from it is not.
Please log in or register to report this question.
Comparing a lightweight ceramic fibre lining with a dense refractory for a batch furnace, the fibre lining
Answer: C
The stored heat lost on every shutdown is a large share of a batch furnace's fuel, and a low mass lining reduces it substantially. Dense refractory resists abrasion and impact far better, which is why it survives in continuous and heavily worked furnaces.
Please log in or register to report this question.
None of the following is a loss head in the indirect method except
Answer: D
Air always carries some water vapour, which is heated and discharged, and it appears as a small loss head of a few tenths of a per cent. Fan power, chemicals and depreciation are all outside the thermal boundary of the calculation.
Please log in or register to report this question.
