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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 steam flow to SH coils resulting into higher main steam temperature.

7-High moisture fuel: If the fuel moisture is more than required, then water present in the fuel absorbs heat from furnace & transfer heat convectively to SH coil.





8-Low GCV fuel: Burning of low GCV coal in furnace releases more heat & hence MS temperature increases.

Note: Burning of high GCV fuel with high moisture also leads to temperature shoot-up.

9-Failure of attemperator control system or wrongly tuned attemperator control valves.



10-Operating the Boilers at more negative draught: This causes more convection heat transfer in SH, (& also at economizers & APH) leading into high main steam temperature

11-More excess air also can lead to fast heat transfer, which can result into high main steam temperature

12-Wrongly designed SH coils: If there is provision of more heating surface in SH coils, then eventually steam temperature always maintains on higher side.

13-Very Clean & scale free surface of SH coils: Leads to faster heat transfer in SH zones causing more steam temperature

14-High moisture content combustion air leads to increase in MS temperature

15-Lesser turbulence in furnace leads more convective heat transfer at SH zone & eventually results high main steam temperature.

16-Wrongly designed SH & furnace zone: High velocity of FG in furnace & SH zone leads to fast heat transfer, this causes high main steam temperature.

17-Mixing of fuels in furnace: Causes uncontrolled excess air & draught which causes main temperature to increase.


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