Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25
Page 26
Page 27
Page 28
Page 29
Page 30
Page 31
Page 32
Page 33
Page 34
Page 35
Page 36
Page 37
Page 38
Page 39
Page 40
Page 41
Page 42
Page 43
Page 44
Page 45
Page 46
Page 47
Page 48
Page 49
Page 50
Page 51
Page 52
Page 53
Page 54
Page 55
Page 56
Page 57
Page 58
Page 59
Page 60
Page 61
Page 62
Page 63
Page 64
Page 65
Page 66
Page 67
Page 68
Page 69
Page 70
Page 71
Page 72
Page 73
Page 74
Page 75
Page 76
Page 77
Page 78
Page 79
Page 80
Page 81
Page 82
Page 83
Page 84
Page 85
Page 86
Page 87
Page 88
Page 89
Page 90
Page 91
Page 92
Page 93
Page 94
Page 95
Page 96
Page 97
Page 98
Page 99
Page 100
KAPPA ANALYSIS WORLD PULPPAPER72 board machines that currently produce 1331 tons per day of linerboard and corrugating medium. DELAYS IMPACT FIBRE QUALITY AND RUNNABILITY The mills reasoning for the initial trial installation is explained in the internal justification document Because of the small sample size and frequency of the test there is not enough information to react in real-time to variations in chip supply or the cooking process. These tests are performed manually every two hours by the pulp mill lab operator and take about an hour to complete. This delay in feedback of what is occurring during the process has proven to have a negative impact on fibre quality and board machine runnability. Based on the need for more accurate and real- time information a trial Single Point Kappa SPK analyser was installed during the May 2014 annual outage in the pulp mill. The SPK analyser automatically takes multiple online samples 12 per hour which provide a continuous feedback of the Kappa number. Jack Williamson former pulp mill superintendent and now operations manager at the Green Bay Packaging Wisconsin mill explains the previous dilemma for the pulp mill and downstream machine crews The One snapshot every two hours is not a good indication of variation. The swings really give the paper makers problems. suited to unbleached kraft pulp mills. The analyser provides an accurate on-the-spot reading in a few minutes and there is no need for the additional delays and complexity of remote sampling devices valves and sample transport lines to a central analysis unit. The SPK is mounted directly in the process flow and performs all the necessary operations for sample measurement including screening washing and measurement of the pulp fibre lignin content using absorption of ultra-violet light. It is a simple and direct measurement with an improved sampling frequency of 10 to 12 samples per hour with the SPK compared to 2 or 3 samples per hour with the multi-point analyser. Figure 1 shows that the SPK analyser is installed at the inlet of the screen accepts tank after the hot refining and screening. At this location the analyser shows trends in the blow Kappa numbers from the digesters. With the frequent sampling Lee says it is possible for the operators to determine which digester the pulp is coming from since the interval between blows of the five digesters averages 2.25 hrs. The first signs of an incoming blow are recognised by the meter after about 15 to 20 minutes process delay and the blow progress is followed thereafter. Results highlights - Operators adjust cooking conditions to reduce Kappa variations by more than 50 allowing an increase in target Kappa number - Pulp yield increase of 1 means 300000y in wood and energy savings - Board machine operators rely on real-time readings to adjust - Reduced web breaks on board machines have been documented manual tests were subjective and varied from tester to tester and shift to shift. The online measurement would remove the testing subjectivity and help us to improve runnability and keep the machine speed up. With high Kappa we would run into refining limitations and problems with strength tests. With low Kappa we had to reduce machine speeds. Sean Lee pulp mill superintendent adds One snapshot every two hours is not a good indication of variation. The swings really give the paper makers problems. SIMPLE DIRECT MEASUREMENT Unlike multi-point Kappa analysers that are used typically in bleached kraft pulp mills the SPK-5500 is purposely designed for a single point online measurement that is particularly Figure 1. SPK installation in the fiber line process