Fuel flow to the burner Change in the kiln speed
Change in the speed of the ID fan
The operator needs to use one or all of its three controllers to keep these variables inside their limits. The operator must be alert and correct any out of range conditions as soon as it reaches the limits of tolerance.
Page 53 of 98
Correction should be made promptly, but care must be exercised to avoid overreacting as this could lead the kiln to an upset.
THE 27 CONDITIONS (KURT E. PERAY)
Because any of these variables can be within, below or above the allowable range, there are 27 possible conditions that will be encountered by the operator.
These are shown graphically in the following figure. Note that a case number has been assigned to each condition as an aid to identification. This chart should be used by the operators to understand the logic of good kiln operation procedures where the Back-End Temperature, the Burning Zone Temperature and Oxygen level were all taken in consideration in order to make a logic correction to an out of range variable.
Case Condition Action to be taken Reasons
1
BZT low Ox low BET low
When BZT is drastically low, a) reduce kiln speed b) reduce fuel rate When BZT is slightly low,
c) increase ID fan speed d) increase fuel rate
a) to increase BZT and BET
b) to move Ox percentage into range c) to raise BET and Ox
d) to raise BZT and Ox into range 2
BZT low Ox low BET OK
a) reduce kiln speed b) reduce fuel rate c) reduce ID fan speed
a) to raise BZT
b) to raise Ox percentage into range c) to maintain BET
3
BZT low Ox low BET high
a) reduce kiln speed b) reduce fuel rate c) reduce ID fan speed
a) to raise BZT b) to increase Ox c) to reduce BET 4 BZT low Ox OK BET low
When BZT is drastically low, a) reduce kiln speed When BZT is slightly low,
b) increase ID fan speed c) increase fuel rate
a) to raise both BZT and BET b) to raise BET and Ox c) to raise BZT
5
BZT low Ox OK BET OK
When BZT is drastically low and Ox is in lower part of range,
a) reduce kiln speed b) reduce fuel rate c) reduce ID fan speed
a) to raise BZT b) to raise Ox c) to maintain BET
Page 54 of 98
When BZT is slightly low and Ox is in higher part of range,
d) increase fuel rate d) to raise BZT
6
BZT low Ox OK BET high
When BZT is drastically low, a) reduce kiln speed b) reduce fuel rate c) reduce ID fan speed When BZT is slightly low and Ox in higher part of range,
d) reduce ID fan speed
a) to raise BZT b) to raise Ox c) to lower BET
d) to reduce BET and raise BZT
7
BZT low Ox high BET low
When BZT is drastically low, a) reduce kiln speed b) reduce ID fan speed When BZT is slightly low,
c) increase fuel rate
a) to raise both BZT and BET b) to maintain BET
c) to raise BZT and lower Ox & BET. BET should be rising also, if not keep increasing fuel rate and ID fan speed
8
BZT low Ox high BET OK
When BZT is drastically low, a) reduce kiln speed b) reduce ID fan speed When BZT is slightly low,
c) increase fuel rate
a) to raise BZT
b) to maintain BET. If Ox is still available after this move, increase fuel also
c) to raise BZT and lower Ox
9
BZT low Ox high BET high
When BZT is drastically low, a) reduce kiln speed b) reduce ID fan speed c) increase fuel rate When BZT is slightly low,
d) reduce ID fan speed
a) to raise BZT
b) to lower BET and Ox c) to raise BZT and lower Ox
d) to raise BZT and reduce BET & Ox 10
BZT OK Ox low BET low
a) increase ID fan speed b) increase fuel rate
a) to raise BET and Ox b) to maintain BZT 11
BZT OK Ox low BET OK
a) decrease fuel rate slightly a) to raise Ox
12
BZT OK Ox low BET high
a) reduce fuel rate b) reduce ID fan speed
a) to increase Ox
b) to lower BET and maintain BZT 13
BZT OK Ox OK BET low
a) increase ID fan speed b) increase fuel rate
a) to raise BET b) to maintain BZT 14 BZT OK Ox OK BET OK
None, however do not get overconfident
15 BZT OK
Ox OK
When Ox is in upper part of range,
Page 55 of 98
BET high a) reduce ID fan speed
When Ox is in lower part of range,
b) reduce fuel rate c) reduce ID fan speed
a) to reduce BET
b) to raise Ox
c) to lower BET and maintain BZT 16
BZT OK Ox high BET low
a) increase ID fan speed b) increase fuel rate
a) to raise BET
b) to maintain BZT and reduce Ox 17
BZT OK Ox high BET OK
a) reduce ID fan speed slightly a) to lower Ox
18
BZT OK Ox high BET high
a) reduce ID fan speed slightly b) reduce fuel rate slightly
a) to lower BET and Ox b) to maintain BZT
19
BZT high Ox low BET low
When BZT is drastically high, a) increase kiln speed b) increase ID fan speed c) reduce fuel rate When BZT is slightly high,
d) increase ID fan speed
a) to avoid overheating BZT b) to raise BET and Ox c) – do –
d) to lower BZT and raise BET & Ox
20
BZT high Ox low BET OK
When BZT is drastically high, a) increase kiln speed b) decrease fuel rate c) increase ID fan speed When BZT is slightly high,
e) increase ID fan speed
a) to avoid overheating b) to lower BZT
c) to increase Ox and maintain BET d) to lower BZT and raise Ox
21
BZT high Ox low BET high
When BZT is drastically high, a) increase kiln speed b) reduce fuel rate When BZT is slightly high,
c) decrease fuel rate
a) to lower BET and avoid overheating
b) to lower BZT and increase Ox c) to lower BZT, BET and increase Ox
22
BZT high Ox OK BET low
When BZT is drastically high, a) increase kiln speed b) increase ID fan speed c) reduce fuel rate When BZT is slightly high,
d) increase ID fan speed
a) to avoid overheating b) to raise BET
c) to lower BZT
d) to raise BET and lower BZT (see note A)
23
BZT high Ox OK BET OK
When BZT is drastically high, a) increase kiln speed b) decrease fuel rate c) increase ID fan speed When BZT is slightly high,
d) reduce fuel rate
a) to avoid overheating b) to lower BZT
c) to maintain BET
d) to lower BZT (see note A)
24 BZT high
Ox OK
When BZT is drastically high,
Page 56 of 98
BET high b) decrease fuel rate
When BZT is slightly high, c) decrease fuel rate
b) to lower BZT
c) to lower both BZT and BET (see note A)
25
BZT high Ox high BET low
When BZT is drastically high, a) increase kiln speed b) increase ID fan speed When BZT is slightly high,
c) increase ID fan speed
a) to avoid overheating
b) to increase BET and lower BZT c) to raise BET & lower BZT (note A)
26
BZT high Ox high BET low
When BZT is drastically high, a) increase kiln speed b) increase ID fan speed c) decrease fuel rate When BZT is slightly high,
d) reduce fuel rate
a) to avoid overheating b) to maintain BET c) to reduce BZT
d) to lower BZT (see note A)
27
BZT high Ox high BET high
When BZT is drastically high, a) increase kiln speed b) decrease fuel rate When BZT is slightly high,
c) decrease fuel rate d) decrease ID fan speed
a) to lower BZT and BET b) – do –
c) to lower BZT
d) to lower BET (see note A)
NOTE A: If the % O2 increased during this adjustment, disregard it until temperatures are brought under control.