单项选择题
A.acidity has increased B.viscosity has decreased C.demulsibility has improved D.foaming is guaranteed to occur
When an auxiliary boiler is panting and emitting black ...
单项选择题When an auxiliary boiler is panting and emitting black smoke, you should （）.
A.increase the fuel oil temperature B.decrease the fuel oil temperature C.decrease the fuel oil supply pressure D.increase the air supply
With regards to a diesel engine crankcase explosion, th...
With regards to a diesel engine crankcase explosion, the most violent is the（） (1) primary explosion (2) secondary explosion
A.(1) only B.(2) only C.both (1) and (2) D.neither (1) or (2)
Waterside scale in a fire-tube boiler may cause （）.A.in...
单项选择题Waterside scale in a fire-tube boiler may cause （）.
A.increased heat transfer B.fireside erosion C.high steam demand D.overheated tubes
