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Evaluation of Cooking Processes for Trema orientalis (Nalita) Pulping
M Sarwar Jahan Pulp and Paper Research Division, BCSIR Laboratories, Dhaka, Dr. Qudrat-I-Khuda Road, Dhaka-1205, Bangladesh IUFRO ALL Division 5 Conference : Pulp and Paper B
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Lay-out of the presentation
Introduction Pulping of T. orientalis in different processes Pre-bleaching of T. orientalis pulp in different processes ECF and TCF bleaching Conclusions
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Present scenario of Pulp and Paper Mill in Bangladesh
Introduction Present scenario of Pulp and Paper Mill in Bangladesh Raw materials Kharnaphuli Pulp and Paper Mills(KPM) Kharnaphuli Rayon Mill Sylhet Pulp and Paper Mills (SPPM) North-Bengal Pulp and Paper Mills Khulna Newsprient Mills Gmelina arborea Bamboo Albizzia Moluccana Reeds Bagasse Gewa (Excoecaria agallocha) } 26 paper mills based on recycled and imported pulp
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Allocated Forestland for KPM: 51,000 ha
Allocated Forestland for SPPM: 24,000 ha Forestland in Bangladesh: 10.2 % Population density: 1079/ Km2 It is almost impossible to increase forestland for industry. So we have to increase fiber yield using existing allocated forestland.
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The most potential fast growing species in the environment of Bangladesh
Exotic species- Raintree (Samanea saman), Acacia spp., Eucalyptus spp. Native species- Gmelina arborea, A species named Trema orientalis has been found which has faster growth than any other species in Bangladesh
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Trema orientalis garden
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Cross section three years old Nalita stem
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Chemical and morphological properties of trema orientalis
α-cellulose % pentosan % Lignin Fiber length mm 48-50 22-23 20-24 0.83 Trema orientalis can substitute of short length fibrous raw material in pulp mill, which is needed for printing quality paper
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Goal Increased fiber yield for pulping Increased pulp yield
Better bleaching
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Pulping Cooking process Soda Soda-anthraquinone (AQ) Kraft
Alkaline-sulfite-AQ-MeOH (ASAM) Formic acid Acetic acid
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Cooking conditions of different pulping processes
Soda Soda-AQ Kraft ASAM Acetic acid Formic acid AA, % as Na2O AQ, % Sulphidity, % Methanol. % (v/v) Na2SO3: NaOH Acetic acid, % Formic acid, % Material : Liquor ratio Temperature, oC Time at max temp., min 17 - 1:4.5 170 120 0.1 30 20 80:20 180 90* 1:10 107 90 *0.2% HCl
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Results of Trema orientalis pulping in different processes
Soda Soda-AQ Kraft ASAM Acetic acid Formic acid Screened yield, % Reject, % Total yield, % Kappa number Viscosity, mPa.s 44.8 0.2 45.0 20.8 15.5 45.9 46.1 18.4 16.6 45.3 45.5 10.8 13.4 51.7 1.1 52.8 30.4 56.0 39.1 21.8 55.9 34.1 15.7
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Comparison of pulping processes relative to soda process
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Evaluation of papermaking properties
In papermaking, it is common practice to refine/beat pulp for improving strength properties by mechanical treatment of fiber, which facilitates fiber bonding.
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Beatability of different pulps of T. orientalis
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SR number Vs tensile of trema orientalis pulp
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SR number vs burst of trema orientalis pulp
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SR number vs tear of trema orientalis pulp
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SR number vs double fold no. of Trema orientalis pulps
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Prebleaching Oxygen Xylanase Peroxyacid
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Effect of prebleaching in soda pulp
O-oxygen, PFA-Peroxyformic acid, X-Xylanase
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Effect of prebleaching in soda-AQ pulp
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Effect of prebleaching in kraft pulp
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Effect of prebleaching in ASAM pulp
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Bleaching DED QPP
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DED and QPP bleaching of oxygen delignified different Trema orientalis pulps
oSR T TI BI DFN D O B V Soda DED QPP Soda-AQ DED QPP Kraft DED QPP ASAM DED QPP 42 41 43 37.7 38.5 42.2 39.1 31.7 34.4 48.5 42.5 6.6 5.8 8.4 8.5 7.9 8.8 10.6 10.5 3.1 3.2 3.7 3.0 4.9 4.3 114 128 111 252 175 698 674 0.512 0.519 0.564 0.549 0.547 0.570 0.534 0.578 87.6 87.9 87.4 86.6 88.1 86.7 88.8 83.7 79.8 74.6 76.0 73.2 80.9 77.3 86.1 79.1 10.1 12.4 11.9 10.3 13.1 13.4 T- Tensile index, N.m/g, TI-Tear index, mN.m2/g, BI- Burst index, kPa.m2/g DFN-Double fold number, D- Density, g/cc V-Viscosity, mPa.s, B- Brightness, %, O-Opacity, %
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DED bleaching of xylanase treated different Trema orientalis pulps
oSR T TI BI DFN D O B V Soda Soda-AQ Kraft ASAM 32 36 42 37 37.7 40.2 39.7 47.4 6.3 8.6 7.9 10.7 3.3 3.5 2.8 4.8 82 130 105 1250 0.502 0.549 0.602 0.587 86.8 87.3 86.9 86.7 80.1 76.6 82.9 88.6 10.8 11.9 11.1 15.8 T- Tensile index, N.m/g, TI-Tear index, mN.m2/g, BI- Burst index, kPa.m2/g DFN-Double fold number, D- Density, g/cc V-Viscosity, mPa.s, B- Brightness, %, O-Opacity, %
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Comparison of DED bleaching between oxygen and xylanase delignified pulp
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QPP bleaching of peroxyformic acid treated Trema orientalis pulps
oSR T TI BI DFN D O B V Soda Soda-AQ Kraft ASAM Formic acid Acetic acid 36 35 37 45 51 35.4 38.2 38.5 41.9 19.4 27.4 5.1 4.7 9.9 10.9 6.4 4.3 1.6 2.0 2.1 4.0 1.9 1.0 11 12 39 465 8 6 0.550 0.585 0.575 0.551 0.470 0.352 88.3 88.6 82.8 81.7 89.2 87.3 73.7 71.7 78.8 83.0 75.2 10.8 12.3 18.0 11.6 4.9 T- Tensile index, N.m/g, TI-Tear index, mN.m2/g, BI- Burst index, kPa.m2/g DFN-Double fold number, D- Density, g/cc V-Viscosity, mPa.s, B- Brightness, %, O-Opacity, %
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CONCLUSIONS Trema orientalis is a high biomass producing, shorter length fiber tree for papermaking. It is a brighter in appearance thus easier to bleach. The ASAM process produced pulp of higher yield, lower kappa number, higher viscosity and initial brightness. Prebleaching reduced kappa number by % depending on prebleaching treatment. Oxygen prebleaching reduced the highest kappa number. ASAM process showed the best and soda process showed the least results in oxygen treated DED and QPP bleaching. Enzyme prebleached pulp gave better brightness in subsequent DED bleaching. ASAM process showed the best results in enzyme treated DED bleached pulp among the four processes. Peroxyformic acid treated pulp responded very well in QPP bleaching. In this process, maximum brightness 83 % was attained in formic acid pulp, but strength properties were inferior. Soda-AQ pulp responded poor bleachability.
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THANK YOU
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