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Technical Cement Forum / operation interlocks required

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armankhan 15/08/2012 21:04:34

operation interlocks required

respected seniors.

we have VRM loesche 500tph. we take hot gases from kiln passing after conditioning tower.

my question is when kiln feed stopped in any emergency conditions our inlet negative pressure to conditioning tower and also mill inlet negative pressure disturbed and goes down due to which lifting of material from mill disturbed and sudden vibration occured which stop mill.... so plz suggest any good interlocks to avoid mill stoppage when kiln feed diverted or stooped for just minutes in emergency conditions.....

Engr 10/09/2012 02:54:55

Dear arman, can u tell us that when your feed trip then what happened to the ID fan speed and how much pressure change for mill inlet before and after the feed tripping.

viswam 10/09/2012 11:35:20

sir,

To run VRM when the kiln feed is reduced condition ( low air volume )

1) Opne the re-circulation damper in VRM and maintain inlet draft - 5 to - 6 mbar

2) If you have Booster fan duct ( i.e., air duct from cooler to VRM inlet open it )

and maintain mill inlet - 5 to -6 mbar

3) Sudden stopping of kiln increase the air volume by doing the above points

and reduce the mill feed and Gr., pr and table water spray to avoid mill vibrations tripping

thank you .

gks 16/09/2012 06:33:33

Dear friend

1. Excess flow of gas due to kiln process parameter may effect flow of gas through the gas chamber in VRM.So excess flow can pass through bag house by auto closed loop ( bag house inlet pressure vs fan speed ). { For three fan system}.

2. If water spray in down commer duct .It will control gas volume throughPH & VRM will not tripped due to flow distrubence.( PH FAN inlet temp. vs water flow closed loop) .

3. If there is margin in RM FAN than flow vs mill inlet draft closed loop may effective.If there is no margin in RM FAN FLOW than reduced DP set point or Make margin to control mill o /l temp. vs mill water spray ( Amount of excess flow through PH vs High capacity water pump for VRM ).

4. If kiln stopped and avoid the tripping VRM use the fresh air damper for getting gas volume ( Fresh air damper vs mill inlet draft closed loop ) or (recirculation damper vs mill o/l temp. loop).

Thank for sharing problem.

GK SHARM

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