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Showing posts with the label Boiler

Chain conveyor troubleshoot guide

  Problem Identification & Corrective Action Sl No. Problem Potential Cause Solution 1 Chain rises off from sprocket 1.Excess chain slack. 2.Excess wear at the bases of sprocket teeth. 3.Excess chain extension. 4.Foreign material stuck to the bases of sprocket teeth. 5.Reverse rotation of conveyor 6.Uneven chain tightening of chain 1.Adjust the amount of slack equally at both sides. 2.Carryout hard facing of the sprockets 3.Replace the elongated chain parts. 4.Remove the foreign material from the bases of the teeth. 5.Avoid reverse rotation of the conveyor when chain tightened is uneven 2 Chain separates poorly from the sprocket. 1.Sprocket misalignment. 2.Excess chain slack. 3.Excess wear at the bases of sprocket teeth. 4.Uneven chain tightening of chain 1-Adjust alignment. 2-Adjust the amount of slack.

Why does Boilers main steam temperature increase more than design?

  1-Decrease in Economiser inlet feed water temperature Upon decrease in economiser inlet feed water temperature, fuel consumption in furnace increases & hence main steam temperature increases more than desired. 2-Load on Boilers is more than design Main steam temperature increases if the steam generation is more than actual designed 3-Leakage in super heater (SH) coils If there is any leakages in SH coils, steam flow to SH coil decreases & hence main steam temperature increases. 4-Choking in Super heater coils Super heater coils Choking due to foreign materials & internal scaling due to poor water chemistry leads to less steam flow through coils resulting into higher main steam temperature due to poor heat transfer. 5-Passing of start-up vent control valve Passing of start-up control valve loads more on Boiler steam generation, hence main steam temperature increases 6-Passing or pop up of drum safety valves : Lifting of drum safety valves lead to less ste

Objective & Viva Questions & Answers for preparation of Boiler operation Engineer (BOE) exam & Boiler Interview

1-Why Boiler is considered as explosive equipment / system? Boiler involves the generation of steam at higher pressure & temperature upon release of this into atmosphere could cause disasters. 2-How do you specify the Boilers? Boilers are specified by their operating pressure, temperature, steam generating capacity & even by heating surface. 3-What are the various circuits involved in Boilers? Water circuit, Steam circuit, air circuit & flue gas circuit 4-Write down the various energy used / generated in power plants? Chemical energy (fuel) Thermal energy (Heat present in flue gases & steam) Kinetic energy (rotation of Turbine rotor), Mechanical energy (shaft power on Turbine) Electrical energy (In generators). 5-Why steam, is generated at high pressure & temperature? High pressure & temperatures steam is having more heat content & also has more potential to do work. 6-At what pressure do you carryout Hydraulic test on Boilers?

Boiler calculations for Boiler operation Engineer Exam (BOE)

  1-Oxygen percentage in Boiler outlet flue gas is 4.9%, then what will be the percentage of excess air? We have excess air EA = O2 X 100 / (21-O2)                                    EA = 4.7 X 100 / (20-4.7)                                    EA = 30.71% 2-Calculate the Oxygen level (O2) in flue gas, if excess air is 25% We have Excess air EA = O2 X 100 / (21-O2)                                    25 = O2 X 100 / (21-O2)                                    O2 = 4.2% 3-A Boiler’s combustion system requires 5.5 kg of air for burning 1 kg of fuel, then calculate the total air required for complete combustion if its flue gas has 4.1% of O2 We have, Total air = (1 + EA/100) X Theoretical air EA = O2 X 100 / (21-O2) EA = 4.1 X 100 / (20-4.1) = 25.78% Therefore Total air = (1 + 25.78/100) X 5.5 = 6.92 kg of air per kg of fuel burnt 4-A Coal fired boiler having total heating surface area 5200 M2 produces 18 kg of steam per square meter per hour of heating surface, then calculate the Boiler cap