025_tsp Qjp400generalzwd_hzf_wxw 0807 Preca Study

ATC REPORT Activity:

STUDY

CHINA / QUJIANG Plant Precalciner study by ZHANG WEIDONG//HAN ZHENFENG// WANG XIANGWEI ATC, 17th-21st July 2006

Distribution: Region BU Plant

Zhou Wei//Zhang JingHong

ATC

Sinan Urhan//Renaud deBelmont

Other Codification

TSP QJP400GENERAL/ZWD_HZF_WXW study

0807

Preca

TABLE OF CONTENTS A.

Executive Summary.......................................................................................................... 3

B.

Main Report....................................................................................................................... 6 1

Introduction..................................................................................................................... 6

2

Work Done...................................................................................................................... 6

3

Analysis / Argument / Conclusions..................................................................................6 3.1

Background Information...........................................................................................6

3.2

Safety...................................................................................................................... 8

3.3

Precalciner Survey...................................................................................................9

3.4

False Air Audit........................................................................................................15

3.5

Fan Efficiency........................................................................................................16

4

Recommendations........................................................................................................17

5

Acknowledgements.......................................................................................................18

6

Appendices.................................................................................................................... 18

A.

EXECUTIVE SUMMARY

Objectives: The objective of the mission was to explain the poor combustion in the precalciner although residence time is high enough and to advice on possible modification, Aside from the initial objectives, some QW relative missions will be completed: Fan efficiency Audit for #3 Kiln ID Fan, ESP Fan; #1 ESP Fan. Organize a session to follow up” QW recommendations tracking”. Results / Findings Safety: 

The accesses are very poor, no proper step or ladder to arrive the measuring points.



Many Preheater concrete beams overhead the accesses are too low to pass through, and no necessary alarm marks.

QJP Precalciner Evaluation: Although the kiln feeding variability made hardly possible any reliable investigation, it can be said that the CO problem does not come from pre-calciner dimension (big enough). O2 level at C2 exit is in average too low and may be a root cause on top of the huge circuit variation because of kiln feed variability. Burner design should be further investigated. Items Residence time

Target/Normal ~ 2.0s

PC temperature profile PC exit gas temperature CO kiln exit O2 kiln exit CO PC exit gas O2 PC exit gas Temperature In main section Burn condition by visual inspection Stable fuel splitting PC

Existing status 3.6s

Evaluation OK

Uniform and reasonable.

PC upper is higher than middle and bottom; huge variations--- Max 98℃ between two points at same level.

Bad

Stable ±5℃

Max. 24℃

Bad

2.0 sec (needs to be > 4.5 sec to allow for NOx reduction) – allow burnout of CO. Lafarge Precalciners Residence time(s):

Figure 3: Gas residence time in precalciner in Lafarge area

From the Precalciner Study Technical Agenda:

Page 11 of 18

 Precalciner heat loading (kcal/m3.h): QuJiang precalciner heat loading is 83kcal/m3h. Normally, the higher the clinker production the higher the quantity of fuel, and the higher Precalciner heat loading. Presently the trend is towards heat loading of 50~70Mcal/m3h. Lafarge plant Precalciner heat loading:

Figure 4: Precalciner heat loading data in Lafarge area

 Precalciner Loading (t/m3d): Page 12 of 18

QuJiang precalciner material loading is 3t/m3d. There is still room in QJP precalciner to increase production by around 30% (to bring to 4t/m3d) : Supplier

PC type

Polysius

Prepol

PC Loading (t/m3d) 4–6

Inline

4 – 4.5

Separate Line

7 – 7.3

FLS Fuller IHI KHD ALL Kilns

Comments

PC combustion in TA only

4.5 – 6 NSF

6.0 – 7.5

Pyroclon

3.5 – 4

PyroTop

2.5

Able to operate < 600 mg/Nm3 NOx

5.5 Table 3: Different type precalciner loading

Lafarge plant Precalciner loading (t/m3d):

Figure 5: Different precalciner loading in Lafarge area

And we got QuJiang precalciner measurement and calculation like this:

Page 13 of 18

Table 4: QuJiang PC measurement and calculation 200607

3.3.3 Visual inspection of precalciner: We inspected the interior of Precalciner on the same level (measurement point C) through inspection holes, point C1 was very dark at the same time point C2 flame was very bright. Many sparkles were found inside the Precalciner even though at the outlet point D, This implies the Precalciner combustion condition is poor, burnout rate is low.

Photo 4: Precalciner internal combustion condition in QuJiang 200607

3.3.4 Precalciner Evaluation According to the Precalciner measurement and gas analysis, we can get some conclusion like this: Items Gas velocity in PC

Target/Normal 4.5~10m/s Page 14 of 18

Existing status 5m/s

Evaluation OK

Residence time PC heat loading PC loading Decarbonation degree

5.5~6.5m/s FLS >3.5s 3

83 Mcal/m h

A bit high

2.5~7.5t/m3d

3t/m3d

OK

92~95%

OK

No sparkle at outlet >50%

91~95% PC upper is higher than middle and bottom;Max. variations 98℃ between two points at same level. 24℃ Max. Normal 2014~6250ppm Seldom ＜500ppm 0.8~3.2% Unstable Max. variations 45℃ Many sparkles was found in different section Around 60%

＜0.2%

No testing

Uniform and reasonable.

CO PC exit gas O2 PC exit gas Temperature In main section Burn out rate by visual inspection Stable fuel splitting PC Unburned carbon hot meal

OK 3

50~70Mcal/m h

PC temperature profile

PC exit gas temperature

3.6s

Stable ±5℃ ＜500ppm 2~3%without CO Stable

Bad Bad Very bad Bad Bad Bad OK

Table 5: The comparison between QuJiang precalciner and target 200607

After the measurements, it was found that the combustion is not proper in the total pyro system. The real Calciner performance could not be evaluated mainly because of the Kiln Feed Fluctuations upto 40%. It is very difficult to determine the Calciner performance with these fluctuations. Therefore, the Kiln feed has to be maintained uniform quantity +/-1% before we really evaluate the Calciner. The Calciner performance will be studied in detail and the Calciner modification recommendations will be done once the Process is stable with Kiln feed at reasonably within the acceptable limits. 3.4

False Air Audit

False air ratio was 61.1% between Precalciner exit and ID fan inlet, that resulted in high power consumption in clinker production (increase at least 2kwh/tck more). And Drying Crusher was the main leakage point where false air is 47.1%. Another main leakage point is dedust cyclone, we heard strong air leakage sound from there.

Page 15 of 18

Figure 6: The false air profile in pyroprocessing system

3.5

Fan Efficiency

This mission fan efficiency audit has covered #3 Kiln ID Fan, ESP Fan; #1 ESP Fan. We didn’t complete the #3 kiln cooler ID Fan audit because of the lack of power factor. The details of the Fans’ efficiency audit are placed in appendices. The total Power savings are calculated to be 8 – 9 Kwh/t of clinker. (Assumed that Kiln ID Fan Efficiency is taken as 40% and not 17%) Plant to contact with fan experts to increase fan efficiency.

Page 16 of 18

4

Recommendations

Action №1: Proper step or ladder for the measurement points should be installed; some handrails must be installed also. №2: Alarm marks should be fixed on the Preheater concrete beams overhead the accesses. №3: Gangways on the scaffolding optionally must be carried away to keep from falling down. Objective: Safety Way to implement: Install handrails, step and ladder. Carry away gangways and scaffolding. Reference documents: Safety guideline. Plant or BU responsible: Plant. Expected result: Decrease LTI.

Action №4: Install thermocouples at Precalciner bottom, middle, upper and kiln inlet. Cross-check Preheater manometers and thermocouples regular to achieve more uniform combustion and decarbonatation. Objective: Optimize preheater and precalciner combustion Way to implement: To buy and install thermocouples at proper position. ATC can advice. Reference documents: Combustion optimization. Plant or BU responsible: Plant. Expected result: Increase output and decrease heat consumption.

Action №5: Improve vacuum filter performance to reduce the feed material quantity and quality deviation. Objective: Stabilize all pyroprocessing system. Way to implement: Try to find high quality filter cloth and improve vacuum equipment. Reference documents: Combustion optimization. Plant or BU responsible: Plant, BU and ATC. Expected result: Improve pyroprocessing system stability and increase capacity.

Action №6: Modify coal transport pipe to decrease the possibility of coal feed fluctuation Objective: Decrease the fluctuation of coal feed to calciner Way to implement: Modify incline coal transport pipe to horizontal or vertical pipe.. Page 17 of 18

Reference documents: Combustion optimization. Plant or BU responsible: Plant. Expected result: Improve pyroprocessing system stability. Action №8: Improve drying crusher air sealing and weld or change duct to reduce false air Objective: Decrease false air Way to implement: Weld and change worn out duct. Improve air sealing at drying crusher. Reference documents: QW. Plant or BU responsible: Plant. Expected result: Decrease power consumption 2KWh/kgcli. Action №9: Try to control KFUI