Oxygen delignification (OD) process chemistry for Acacia

Transcription

1 Oxygen delignification (OD) process chemistry for Acacia

2 Contents Introduction Background Objectives Results Mill pulp properties Pulp strength & OD selectivity (1) Extractive ti removal & OD selectivity it (2) Conclusions

3 Introduction Economic and environmental benefits of OD have been recognized since 1960s (Fapet 2000) Lower effluent treatment cost Heat recovery Lower refining energy Lower oxygen cost

4 Introduction OD is today well established in industry (Fapet 2000) As environmental issues have now been addressed, research has returned to the performance of this OD technology (Chakar 2000) This study evaluates the response of A. mangium kraft pulp on OD process with respect to pulp strength, basic chemistry, fiber structures and extractives

5 Background 21-25% 25% DZSTS loss of A. mangium kraft pulp after OD compared to 8-14% of other kraft pulps (IPST) A. mangium contains extractives twice as much to those of Eucalyptus wood (Neto, 2004), and eight times as much to those of MHW (pulp)

6 Introduction - 1 Background 21-25% DZSTS loss of A. mangium kraft pulp p after OD compared to 8-14% of other kraft pulps (IPST) Objective Determine key OD process parameter to obtain better selectivity it and pulp strength th

7 Literature review Lignin and extractives content of five hardwoods Lignin a, % Extractives b, % A. mangium B. pendula E. globulus E. urograndis E. grandis a Klason b ethanol/toluene Neto et al, NPPRJ, 2004

8 Literature review Comparison: Hardwoods kraft pulping and bleaching (DEDED) active alkali unbleached ClO 2 bleached %Na 2 O/wood Kappa# %/pulp Brightness A. mangium B. pendula E. globulus E. urograndis E. grandis Neto et al, NPPRJ, 2004

9 Literature review Mill oxygen delignification conditions Acacia MHW Temperature, C O 2 charge, kg/adt NaOH charge, kg/adt ph Consistency, % Reaction time, minutes Starting Kappa number

10 Literature review Effect of alkali charge in OD of sweet gum kraft pulp BS Kappa# BS Viscosity, it cp % NaOH 4% NaOH 1% NaOH 4% NaOH Kappa# Viscosity, cp Bleachability Selectivity Yang et al, IECR, 2002

11 Objectives 1. Determine key OD process parameter to obtain better selectivity and pulp strength 2. Determine the best pretreatment methods prior to OD on extractives ti removal and selectivity improvement

12 Experiment Material Acacia mangium kraft pulp from Indonesia All chemicals were purchased commercially De-ionized water used

13 Experiment Methods OD process: time, temperature, alkali charge, mechanical pretreatment Pulp properties: strength, fiber morphology, cellulose, HexA, charge, extractive, Kappa, viscosity Yates algorithm Four pretreatment methods

14 Experiment Oxygen delignification experimental conditions a b c d Sample code Reaction time, min Temperature, C NaOH charge, g/kg OD pulp O 2 pressure, kpa 1,034 1,034 1,034 1,.034 1,034 1,034 1,034 1,034 1,034 1,034 1,034 1,034 Consistency, % Quantum mixer time, sec

15 Experiment Oxygen delignification experimental condition for Yates algorithm Experiment number y1 y2 y3 y4 y5 y6 y7 y8 Reaction time, min Temperature, C NaOH charge, g/kg OD pulp O 2 pressure, kpa 1,034 1,034 1,034 1,034 1,034 1,034 1,034 1,034 Consistency, % Quantum mixer time, sec

16 Experiment Four pretreatment methods ultrasound for 2 hours at 1 % consistency, temperature of 25 C, amplitude 40 %, energy 1.0 MJ, then filtered ed and washed heat up to 70 C for 2 hours at 12.8 % consistency, 0.5% MgSO 4 heat up to 70 C for 2 hours at 12.8 % consistency, 0.5% MgSO 4, 2% NaOH mix in Quantum mixer at speed 2200 rpm, 12.8 % consistency for 5 seconds, 0.5% MgSO 4

17 Experimental Experimental std dev errors Properties % error, avg 1 DZSTS (Dry Zero Span Tensile Strength) WZSTS (Wet Zero Span Tensile Strength) Tensile index Tear index Burst index Brightness Fines Fiber length Fiber curl Fiber kink Kappa number Viscosity Hexenuronic acid DCM extractive Total charge Cellulose/hemicelluloses 2.4

18 Results-detail reaction time, min NaOH charge, g/kg pulp reaction temperature, C mixing time, sec Parameter Unit Pre O 2 Post O Kappa number Viscosity cp HexA Mol/g Total charge eq/g DCM extractive % Alpha-cellulose % Gamma-cellulose % Beta-cellulose % DZSTS kpa WZSTS kpa Tear Index mn.m 2 /g Burst Index kpa.m 2 /g Tensile Index Nm/g Brightness % Fines % Fiber length mm Fiber Curl Fiber Kink index 1/mm

19 Results part 1 10 Hemi/Cel ll:viscosit ty ratio R 2 = Viscosity, cp

20 Results part R 2 = 0.91 ribution to Kappa# #, % Kappa# HexA cont

21 Results part 1 Char rge:kappa a# ratio R 2 = Kappa#

22 Results part 1 Metal profile of Acacia mangium pulp Element Concentration mg/kg K 1,268 Na 14,300 Ca 494 Mg 71.4 Mn 3.5 Cu 1.1 Fe 7.9 Ni Molar Mg/Mn=46

23 Results part 1 Mill pulp properties (1), A. mangium Properties Unit Pre O 2 Post O 2 1 Kappa number Viscosity cp DZSTS kpa % loss 4 WZSTS kpa Tensile index Nm/g

24 Results part 1 Effect of OD process on DZSTS, WZSTS, & tensile index 310 DZSTS WZSTS Tensile Index DZSTS WZSTS Tensile Index 50 DZSTS-W WZSTS kpa a Tensile In ndex, Nm/ g DZSTS-W WZSTS kpa Tensile In ndex, Nm/g Pre O a Reaction time, min b NaOH charge, g/kg 190 Pre O DZSTS WZSTS Tensile Index DZSTS WZSTS Tensile Index 50 TS DZSTS-WZS kpa Tensile Index x, Nm/g DZSTS-WZS STS kpa ex, Tensile Inde Nm/g c 190 Pre O Temperature, o C 20 d 190 Pre O Mixing time, sec 20

25 Results part 1 DZSTS, kpa Pre O2 Post O reaction time, min NaOHcharge charge, g/kg reaction temperature, mixing time, sec pulp C

26 Results part 1 Tensile Index, Nm/g Pre O2 Post O reaction time, min NaOH charge, g/kg reaction temperature, pulp C mixing time, sec

27 Results part 1 Effect of OD process on tear & burst index Tear Index Burst Index Tear Index Burst Index Tear In ndex, mn.m m 2 /g Index, Burst I kpa.m m 2 /g Tear In ndex, mn.m m 2 /g Burst In ndex, kpa.m 2 /g a 3 Pre O Reaction time, min 0.0 b 3 Pre O NaOH charge, g/kg 0.0 Tear Index Burst Index Tear Index Burst Index Tear Index,,2.0 7 mn.m 2 /g Burst Index x, kpa.m 2 /g Tear Index,,2.0 7 mn.m 2 /g Burst Index x, kpa.m 2 /g c 3 Pre O Temperature, o C 0.0 d 3 Pre O Mixing time, sec 0.0

28 Results part 1 DZSTS at different pretreatment time 330 mechanical pretreatment DZST TS, kpa mechanical pretreatment + oxygen delignification OD conditions: t=90 min T=90 C mechanical pretreatment mixing time, sec. NaOH=20 g/kg Cons=12 % O 2 press=1034 kpa

29 Results part 1 DZSTS at different pretreatment time 320 DZSTS, kpa % Pre O mechanical pretreatment time, sec OD conditions: t=90 min T=90 C NaOH=20 g/kg Cons=12 % O 2 press=1034 kpa

30 Results part 1 Tensile index at different pretreatment time Tensile In ndex, Nm/g mechanical pretreatment + oxygen dli delignification ifi mechanical pretreatment OD conditions: t=90 min T=90 C NaOH=20 g/kg Cons=12 % mechanical pretreatment mixing time, sec. O 2 press=1034 kpa

31 Results part 1 Tensile index at different pretreatment time 50.0 Nm/g. Tensile index, % OD conditions: t=90 min T=90 C NaOH=20 g/kg 10.0 Pre O mechanical pretreatment time, sec Cons=12 % O 2 press=1034 kpa 2 p

32 Results part 1 WZSTS at different pretreatment time 290 mechanical pretreatment WZS STS, kpa mechanical pretreatment + oxygen delignification OD conditions: t=90 min T=90 C NaOH=20 g/kg Cons=12 % mechanical pretreatment mixing time, sec. O 2 press=1034 kpa

33 Results part 1 WZSTS at different pretreatment time kpa. WZSTS, % OD conditions: t=90 min T=90 C NaOH=20 g/kg Pre O mechanical pretreatment time, sec Cons=12 % O 2 press=1034 kpa 2 p

34 Results part 1 Effect of OD process on viscosity & brightness Viscosity y, cp a Viscosity Brightness Pre O Reaction time, min Brightne ess, % Viscosit ty, cp b Viscosity Brightness Pre O NaOH charge, g/kg ess, % Brightn Viscosity Brightness Viscosity Brightness Viscosity, cp c Pre O Temperature, o C Brightness, % Viscosity, cp d Pre O Mixing time, sec Brightness, %

35 Results part 1 Effect of OD process on fines, fiber length, curl, & kink Fines %, Fi iber length mm, Kink 1/mm Fines Fiber length Kink index Curl 0.4 Pre O a Reaction time, min Curl iber Kink Fines %, F length mm, 1/mm b Fines Fiber length Kink index Curl Pre O NaOH charge, g/kg Curl Fines %, Fiber length mm, Kink 1/mm c Fines Fiber length Kink index Curl Fines Fiber length Fiber Kink index Fiber Curl Pre O Temperature, o C Curl ines %, Fiber leng Fi mm, Kink 1/mm d Pre O Mixing time, sec Cur

36 Results part 1 Fines Fiber length Fiber Kink index Fiber Curl Fines %, Fi iber length d Kink 1/mm Pre O Mixing time, sec l Curl

37 Results part 1 Effect of OD process on alpha-, beta-, & gamma-cellulose Alpha-cellulose Beta-cellulose Gamma-cellulose Alpha-cellulose Beta-cellulose Gamma-cellulose Alpha- & Beta- cellulose, % a- % Gamma cellulose, Alpha- & Beta- cellulose, % a- % Gamma cellulose, a 20 4 Pre O b 20 Pre O Reaction time, min b NaOH charge, g/kg 4 Alpha-cellulose Beta-cellulose Gamma-cellulose Alpha-cellulose Beta-cellulose Gamma-cellulose Alpha- & Betacellulose, % Gammacellulose, % Alpha- & Betacellulose, % Gammacellulose, % c 20 Pre O Temperature, o C 4 d 20 Pre O Mixing time, sec 4

38 Results part 1 Cellulose/hemicelluloses at different pretreatment time Hemicellulose Cellulose Cell lulose/hemi icellulose, % Mechanical pretreatment time, sec

39 Results part 1 Cellulose/hemicelluloses at different pretreatment time Hemicellulose Cellulose Cellu ulose/hemic cellulose, % Mechanical pretreatment time, sec Molin et al, NPPRJ 2002

40 Results part 1 Hemi/Cellulose:viscosity vs Viscosity 10 r Hemi/C Cell:viscosity R 2 = Viscosity, cp

41 Results part 1 Effect of OD process on total charge & DCM extractives Total ch harge, eq/ /g a Total charge DCM extractive Pre O Reaction time, min DCM ex xt, % Total ch harge, eq q/g b Total charge DCM extractive Pre O NaOH charge, g/kg DCM ext, % Total charge DCM extractive Total charge DCM extractive Total charge, eq/g c Pre O Temperature, o C DCM ext, % Total charge, eq/g d Pre O Mixing time, sec DCM ext, %

42 Results part 1 Effect of OD process on Kappa# & HexA 10 Kappa number HexA Kappa number HexA 30 Kappa number HexA, mol/g Kappa number mol/g HexA, a 4 Pre O Reaction time, min 26 b 4 Pre O NaOH charge, g/kg 26 Kappa number HexA Kappa number HexA 30 Kappa number HexA, mol/g Kappa numbe er HexA, mol/g c 4 Pre O Temperature, o C 26 d 4 Pre O Mixing time, sec 26

43 Diagram-experiment Pulp Mechanical pretreatment 15 sec OD at cons. 12%, O 2 press kpa: t = min T = C C NaOH = g/kg Yates algorithm analysis

44 Results part 1 Yates algorithm analysis Exp. Variables Variables Estimated effects t T C effect DZSTS WZSTS tensile Kappa# y average y t y T y t T y C y t C y T C y t T C t = min, T = C, C = g/kg, 15 sec mechanical pretreatment

45 Results part 1 Yates algorithm analysis Exp. Variables Variables Estimated effects t T C effect DZSTS WZSTS tensile Kappa# y average y t y T y t T y C y t C y T C y t T C t = min, T = C, C = g/kg, 15 sec mechanical pretreatment

46 Results - part 1 Yates algorithm for tensile index Exp. Variables Tensile Calculations Estimated effects t T C Index y Grand average 19.8 y teffect -2.4 y T effect y t T effect 0.1 y C effect -5.5 y t C effect 0.5 y T C effect 1.0 y t T C effect 1.4

47 Results - part 1 Yates algorithm for DZSTS Exp. Variables DZSTS Calculations Estimated effects t T C y Grand average 263 y t effect y T effect y t T effect -1.3 y C effect y t C effect 12.3 y T C effect y t T C effect 15.3

48 Results - part 1 Yates algorithm for WZSTS Exp. Variables WZSTS Calculations Estimated effects t T C kpa y Grand average 203 y t effect y T effect y t T effect -5.7 y C effect y t C effect 7.9 y T C effect y t T C effect 11.4

49 Results - part 1 Yates algorithm for Kappa number Exp. Variables Kappa # Calculations Estimated effects t T C y Grand average 7.3 y t effect -0.7 y T effect -2.3 y t T effect -0.1 y C effect -0.5 y t C effect 0.4 y T C effect -0.4 y t T C effect 0.1

50 Results - part 1 OD selectivity w/o mechanical pretreatment Selectiv vity OD conditions: t=90 min T=90 C Cons=12 % O 2 press=1034 kpa NaOH addition, g/kg Yang et al, IECR 2002

51 Results part 1 Mill pulp properties (1), A. mangium Properties Unit Pre O 2 Post O 2 1 Kappa number Viscosity cp DZSTS kpa WZSTS kpa Tensile index Nm/g Selectivity 0.42 OD conditions: t=120 min T=90 C NaOH=16.7 g/kg Cons=12 %

52 Results - part 1 OD selectivity mechanical pretreatment 15 sec 0.8 Selec ctivity % reduction OD conditions: t=120 min T=90 C Cons=12 % NOH NaOH addition, g/kg O 2 press=1034 kpa

53 Results - part 1 DZSTS vs viscosity Yates data 330 DZSTS S, kpa R 2 = Viscosity, cp

54 Results - part 1 DZSTS vs fiber curl Yates data 0.13 Curl In ndex R 2 = Mohlin et al, DZSTS, kpa TAPPI 1996

55 Results - part 1 DZSTS vs fiber kink Yates data 2.0 Kink index x, 1/mm R 2 = Mohlin et al, DZSTS, kpa TAPPI 1996

56 Introduction - 2 Background A. mangium contains extractives twice as much to those of Eucalyptus wood (Neto, 2004), and eight times as much to those of MHW (pulp) Objective Determine the best pretreatment method prior to OD on extractives removal and selectivity improvement

57 Results - part 2 Metal profile of A. mangium and MHW kraft pulps Metal A. mangium, mg/kg MHW, mg/kg Mg/Mn=40 Cu Fe Mn Mg/Mn=30 Mg Ca Ni < 0.36 < 0.28 Co < <

58 Pretreatment in brief C Pulp Pulp Pulp Pulp Pulp MgSO 4 Ultrasound 2h MgSO 4 MgSO 4 MgSO 4 NaOH washing 70 C, 2h NaOH Mix 5 sec OD MgSO 4 NaOH 70 C, 2h NaOH NaOH OD OD OD OD MgSO 4 0.5%, NaOH 2%, time 1h, temp. 90 C, cons. 12%, O 2 press kpa

59 Results part 2 Mill pulp p properties p (2), pre O 2 Properties Unit Acacia MHW 1 Kappa number Viscosity cp DCM extractive % x 4 Fiber length mm

60 Results - part 2 DCM extractives: w/ & w/o pretreatment 1.2 A % DCM extrac actives, % A A 87% A A A 0.2 M M M A M M M M 0.0 P1 P2 C P1-pre O 2, P2-pre O 2 +ultrasound+wash

61 Results - part 2 Viscosity: w/ & w/o pretreatment 20 A A 16 Viscosity y, cp 12 M M A A A A M M M M A M 8 4 P1 P2 C

62 Results - part 2 Kappa number: w/ & w/o pretreatment M M Kappa nu umber A A M M M M A A A A A M 4 P1 P2 C

63 Results - part 2 OD selectivity: w/ & w/o pretreatment M 300% 8 Selecti ivity M M M M A A A A 50% A 0 C

64 Results - part 2 Metal profile of pre O 2 A. mangium and MHW kraft pulps Metal A. mangium, mg/kg MHW, mg/kg Mg/Mn=40 Cu Fe Mn Mg/Mn=30 Mg Ca Ni < 0.36 < 0.28 Yang et al, Co < < TAPPI 2001

65 Pretreatment in brief C Pulp Pulp Pulp Pulp Pulp MgSO 4 Ultrasound 2h MgSO 4 MgSO 4 MgSO 4 NaOH washing 70 C, 2h NaOH Mix 5 sec OD MgSO 4 NaOH 70 C, 2h NaOH NaOH OD OD OD OD MgSO 4 0.5%, NaOH 2%, time 1h, temp. 90 C, cons. 12%, O 2 press kpa

66 Results - part 2 Pre O 2 fines: ultrasonic & mechanical pretreatment M M M Fines, % A A A 0.0 P1 P3 P4 P1-pre O 2, P3-pre O 2 +ultrasound, P4-Pre O 2 mechanical pretreatment

67 Results - part 2 Pre O 2 fiber length: ultrasonic & mechanical pretreatment 1.0 M M M Fiber len ngth, mm A A A 0.0 P1 P3 P4 P1-pre O 2, P3-pre O 2 +ultrasound, P4-Pre O 2 mechanical pretreatment

68 Results - part 2 Pre O 2 fiber curl: ultrasonic & mechanical pretreatment 0.12 M M M Fiber cu url index 0.08 A A A 0.04 P1 P3 P4 P1-pre O 2, P3-pre O 2 +ultrasound, P4-Pre O 2 mechanical pretreatment

69 Results - part 2 Pre O 2 fiber kink: ultrasonic & mechanical pretreatment 1.0 Fiber kink index, 1/mm m A M A M A M 0.4 P1 P3 P4 P1-pre O 2, P3-pre O 2 +ultrasound, P4-Pre O 2 mechanical pretreatment

70 Conclusions Alkali charge was found to be the most pronounced factor affecting the pulp strength th Alkali charge can be reduced by 50% by applying 15s mechanical pretreatment prior to OD to get similar selectivity to that of mill Extractives removal increased by 60 and 15% for A. mangium and MHW pulps, respectively, by applying ultrasonic pretreatment followed by washing prior to OD OD selectivity it increased by 50 and 300% for A. mangium and MHW pulps, respectively, by applying mechanical pretreatment prior to OD