Bleach Plant Report December 2012 Envoy Development, LLC.
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Transcript of Bleach Plant Report December 2012 Envoy Development, LLC.
Bleach Plant ReportDecember 2012
Envoy Development, LLC
Key Comments From Last Month’s Report• From Sep 26 to Oct 20 costs dropped somewhat to trend to the long term average
($19.39 per ton)• On Oct 21 costs increased to $21.15, an increase of $1.76/ton• Costs are up equally across all stages• FIBER LENGTH: 338-AI-BT5400A
– Has been very high since the same time cost increased. Would this have a significant impact on cost? How does it impact control?
• E CAUSTIC TOTPD RATIO: 338-FR-262– Caustic use has been higher, but recently dropped off; costs fell then as well
• D0 WSHR LOWER POND FLOW: 338-FIC-218– Lower pond flows are at a historical low; there is a correlation between lower lower pond flows
and higher costs.
• E WSHR UPPER POND FLOW: 338-FIC-317; E WSHR LOWER POND FLOW: 338-FIC-318– Decreased around the same time that cost increased; could be impacting the pH treatment of the
pulp going to the D1 stage– Lower pond flow is up while upper flow is down. Why?
• D0 STAGE RAW BRIGHTNESS: 338-AI-257A– Has been very low at around 47 recently. Decrease occurred after cost, though. Suggests a higher
incoming K number or less work in the D0 stage.
BP CHEMICALS COST/TON
• This month’s report focuses on the increase in cost that occurred on November 18– Nov 9 to Nov 18
• $18.79
– Nov 18 to Dec 2• $20.67
– Costs are even higher since Nov 27• $21.86
• The inflection point on October 20 has also continued to stick, averaging $20.44 since then– This was the focus of last month’s
report. We will review these changes here as well.
Summary• This month’s report focuses on the increase in cost that occurred on November 18 as
well as the spike on Nov 27– Nov 9 to Nov 18
• $18.79– Nov 18 to Dec 2
• $20.67– Costs are even higher since Nov 27
• $21.86• pH is extremely low in the E, D1 mixer, D1 washer, and going to storage
– If the pH meter is correct, this needs to be corrected; pH meters are so inexpensive we can’t believe this is the case
– Peroxide use and D1 mixer ClO2 use is high; peroxide is at 20 lbs, which is a red flag there is a serious issue
• Any peroxide residual will act as an anti-chlor– There is a chance that there is a mechanical issue with the E washer– D0 raw brightness is high and k number is average, indicating the problem exists past the
D0 washer– PEROXIDE FLOW TO E STAGE: 366-FIC-479
• Peroxide flow increased by 100% but lbs/ton has not increased. Is the lbs/ton controller even being used? Is the make down system working correctly?
Other Observations• DEFOAMER FLOW TO WASHERS: 732-FYI-186
– Has been at a historical high since around the time cost increased. Has the defoamer vendor changed? Are the washers washing poorly?
• FIBER LENGTH: 338-AI-BT5400A– Fiber length remains above average. Longer fiber length, higher costs. Did HW wood
species change?• KAPPA D0 TEMP TARGET: 338-TR-BT5400A
– Higher D0 temps have never produced low costs. The difference is huge. Why not target 130?
• ALKALINE SEWER TEMPERATURE: 338-TI-638– Stepped up to a historical high on November 28 the day after costs spiked. Is the E
temperature reading correctly? Perhaps the tower is hotter than it is showing.
KPI Overview
Tag Name Tag Description Low Cost Nov 9 to Nov 18
High Cost Nov 18 to Dec 2
Diff of Means
Pct of Means
Z-Score Null Hypothesis
Significant 95%
338-MONY-472 BP CHEMICALS COST/TON 18.73 20.67 1.94 9.4% 7.13 yes
338-FI-138B STOCK FLOW TO PR-WASHR TPD 1136.39 1136.31 0.08 0.0% 0.01 no
PMHWK#.L Pulp Mill HWD K# 10.07 9.96 0.11 1.1% 1.78 yes
338-CI-144 PRE-WASHR FILT CONDUCTVITY 2818.25 2794.17 24.08 0.9% 0.16 no
338-CI-257C D0 STAGE CONDUCTIVITY 4606.96 4701.84 94.88 2.0% 5.92 yes
331-CI-216 BS CONDUCTIVITY 3224.74 3069.28 155.46 5.1% 0.80 no
BPDFBRT.L D1 Washer Brightness 86.50 86.16 0.34 0.4% 0.87 no
• Kappa was higher with the lower cost. Overall, though, the correlation between kappa and cost is very low.• D0 Stage Conductivity increased by 95 with the recent high cost.•Production and brightness did not change significantly.
STOCK FLOW TO PR-WASHR TPD: 338-FI-138BProduction has remained high since Oct 30
Pulp Mill HWD K#: PMHWK#.LAlmost no correlation to cost
PRE-WASHR FILT CONDUCTVITY: 338-CI-144No correlation to cost
D0 STAGE CONDUCTIVITY: 338-CI-257CConductivity was very low when cost was low; there is a slight correlation to cost
BS CONDUCTIVITY: 331-CI-216No correlation to cost
D1 Washer Brightness: BPDFBRT.LBrightness has been very low since Nov 30. Cost has been very high recently, as well,
indicating the operators are having trouble making brightness.
Cost Per Stage• Costs increased at every stage
• D1 Stage saw the largest increase at 15%• This strongly implies more should be done in the D0 stage.
Tag Name Tag Description Low Cost Nov 9 to Nov 18
High Cost Nov 18 to Dec 2
Diff of Means
Pct of Means
Z-Score Null Hypothesis
Significant 95%
338-MONY-276 D0 STAGE COST/TON 10.52 11.45 0.93 8.1% 4.86 yes
338-MONY-368 E STAGE COST/TON 4.21 4.50 0.29 6.3% 2.88 yes
338-MONY-470D1 STAGE CHEMICAL COST/TON 4.00 4.73 0.73 15.4% 7.09 yes
338-MONY-472BP CHEMICALS COST/TON 18.73 20.67 1.94 9.4% 7.13 yes
D0 STAGE COST/TON: 338-MONY-276Correlates very well with total cost and is currently high, but has been at higher levels in
the past.
E STAGE COST/TON: 338-MONY-368Increased by nearly $2 last weekend. This appears to be a result of the increased
peroxide flows. Why did this increase so much?
PEROXIDE FLOW TO E STAGE: 366-FIC-479Peroxide flow increased by 100%. Unreacted peroxide will act as an antichlor. We will
show later that it appears the lbs/ton controller is not being used.
PEROXIDE FLOW TO E STAGE: 366-FIC-479.COPV vs CO. Flow does appear to be accurate.
50% PROXID TO DILUITON TNK: 366-FIC-474
D1 STAGE CHEMICAL COST/TON: 338-MONY-470Increased with total cost on November 18. Has been near a historical high for the last
week and jumped when peroxide use increased.
Flow Meter Evaluation
STOCK FLOW TO PRE-WASHER: 338-FIC-138.COGood correlation
Actual - Predicted Flow: Act-PredNo major changes.
Mixer flows - FI157: MixerFlow-FI157Has continued to hover around 0, showing that ClO2 is accurate.
Recent Cost Spike
D0 STAGE RAW BRIGHTNESS: 338-AI-257AHas been trending up for the last two weeks. Generally, this correlates with lower cost, but this is
currently not the case, an indication the issue is past the D0 washer.
10% CAUSTIC TO D0 REPULP FLOW: 338-FZ-262Low, which correlates with very low pH. Why is the flow so low when pH is low and costs are high?
E Final pH: BPEOFPH.LThis pH is way too low and is causing the D1 stage pH to be low as well. Is the pH meter reading correctly?
PEROXIDE FLOW TO E STAGE: 366-FIC-479Peroxide flow increased by 100% but lbs/ton has not increased. Is the lbs/ton controller even being used?
LBS/TON PEROXIDE TO E STAGE HW: 366-HIC-479HLbs/ton is at normal levels, so why is the flow 100% higher? Stock flow has certainly not doubled.
D1 Mixer pH: BPDMXPH.LThis pH is way too low and it appears to be driving costs quite high.
D1 Washer pH: BPDFPH.LHas been decreasing rapidly over the last week. More evidence D1 stage pH is way too low.
pH to Storage: BPSTGPH.LpH to storage is at historical lows.
November 18 Changes
DEFOAMER FLOW TO WASHERS: 732-FYI-186Has been at a historical high since around the time cost increased. Has the defoamer vendor
changed? Are the washers washing poorly?
E WSHR UPPER POND FLOW: 338-FIC-317Started to increase at the beginning of November and has been at a historical high the past few weeks. We
recommended increasing this in last month’s report, but there doesn’t seem to be any significant effect.
BS WASHER DILUTION FACTOR: 331-FYI-206Increased around the same time as cost, implying the BSW are not washing effectively.
ALKALINE SEWER pH: 338-AI-639Stepped up on November 20, but appears to be a calibration issue.
ACID SEWER FLOW: 338-FI-611Stepped down on November 7 and has continued to decrease. Are pond flows lower?
D0 TOWER CHUTE FLUSH: 338-HIC-263Why is this lower if the production rate is higher?
D0 WSHR H UNIT FLUD PRSUR: 338-PI-228Low pressure suggests poor washing.
SLT SLURRY TO RC MXMUM FLW: 366-FI-226M
Review of October 20 Changes
• Last month we looked into the October 20 changes. This inflection point continues to stick. Here is a review of those changes.
E WSHR DRUM SPEED: 338-SI-312Drum speed was very low when cost increased in October. Overall, there is a slight inverse correlation between drum
speed and cost. This seems counterintuitive since higher drum speeds are typically indicative of poor washing.
D1 WASHER DRUM SPEED: 338-SI-412Drum speed was very low when cost increased in October. Overall, there is a slight
inverse correlation between drum speed and cost.
BLEACH PLANT 35# STEAM TMP: 338-TI-052Stepped down from about 340 to 310 when cost increased.
D0 WSHR POND FLOW RATIO: 338-FY-217AStepped up on October 19 and has steadily increased further since then.
FIBER LENGTH: 338-AI-BT5400AFiber length remains above average. Longer fiber length, higher costs. Did HW wood species change?
BLEACH LOAD: 338-AI-BT5400
KAPPA CLO2 ADDITION TARGET: 338-FR-BT5400A
KAPPA D0 TEMP TARGET: 338-TR-BT5400AHigher D0 temps have never produced low costs. The difference is huge. Why not target 130?
PRE-WSHR FZ-P DIFF PRESURE: 338-PDI-110Has been below average since October 20.
D0 THCK STK PP DSCH PRSUR: 338-PI-135Has been decreasing slightly since October 20.
KNOTTER ACCEPTS PRES: 732-PI-050BHas been above average since October 20.
Other Recent Changes
D0 WSHR REPULPER DIL: 338-MIC-222Stepped down from 58 to 48 on November 28. This could be indicative of drainage
issues on the washer – the mat is wetter coming off the deck.
D0 WSHR HOOD PRESSURE: 338-PIC-207Stepped down on November 28
BLEACH PLANT 35# STEAM FLW: 338-FI-050Has been at a historical high of 43 for the last few days.
10% CAUSTIC TO D0 REPULP FLOW: 338-FQI-262LDropped to a historical low on November 28.
ALKALINE HEAT EXCHANGR CND: 338-CI-031Recently dropped close to 0.
ACID HEAT EXCHANGER COND: 338-CI-036Has also been low recently.
#13 BLCH TRANS TO PM'S FLW: 338-FI-548ARecently reached a historical high.
KNOTTER FEED FLOW: 732-FIC-010.SPSet point fell to 0, but PV did not change; obviously not running in manual, but if it gets
put in manual there will be no flow.
KNOTTER FEED FLOW: 732-FIC-010PV for previous slide.
D0 WSHR INLET BOX PRESURE: 338-PI-208
ALKALINE SEWER TEMPERATURE: 338-TI-638Stepped up to a historical high on November 28. Is the E temperature reading correctly? Perhaps
the tower is hotter than it is showing?
50% CAUSTIC FLOW TO RCOVRY: 366-FI-308
Black Liquor NaOH: PMBLNA.L
#6 BROKE TANK LEVEL: 338-LI-559