Palm Rachis Research Articles

Simulation of the fast pyrolysis of Tunisian biomass feedstocks for bio-fuel production

An optimized model is developed for the production of bio-fuels from biomass using a SuperPro Designer tool. Four types of Tunisian biomass feedstocks including date palm rachis, olive stones, vine stems and almond shells were selected for the fast pyrolysis process simulation. Simulation tests were performed at different temperatures ranging from 450 to 650 °C, and residence times ranging from 0.1 to 10 s and the products yield were determined. The obtained results indicate that a temperature of 575 °C and 0.25 s vapor residence time are the optimum parameters to maximize the bio-oil yield. Comparison between the different feedstocks indicates that a higher bio-oil fraction was obtained from the date palm rachis and vine stem. However, the difference between the samples is not significant and further investigations on the bio-oil properties are requested to select the suitable biomass for bio-oil production in Tunisia. Un modèle pour la production des biohuiles à partir de la biomasse a été développé à l'aide du logiciel SuperPro Designer. Quatre biomasses tunisiennes, qui sont les troncs de palmier dattier, les noyaux d'olive, les tiges de vigne et les coquilles d'amande, ont été sélectionnées pour la simulation du processus de pyrolyse rapide. Les tests de simulation ont été effectués pour différentes températures allant de 450 à 650 °C et différents temps de séjour entre 0,1 et 10 s, et la fraction des différents produits a été déterminée. Les résultats obtenus indiquent qu’une température de 550°C et un temps de séjour de 0,5 s permettent de maximiser la quantité de biohuiles produites. La comparaison entre les différents échantillons montre que le rendement le plus élevé pour la fraction liquide a été obtenu à partir du tronc de palmier dattier et de la tige de vigne. Toutefois, la différence n’est pas significative et des investigations supplémentaires sur les propriétés des biohuiles sont nécessaires afin de choisir la meilleure ressource pour la production de biohuile en Tunisie.

Hydrothermal Pretreatment of Date Palm (Phoenix dactylifera L.) Leaflets and Rachis to Enhance Enzymatic Digestibility and Bioethanol Potential.

Date palm residues are one of the most promising lignocellulosic biomass for bioethanol production in the Middle East. In this study, leaflets and rachis were subjected to hydrothermal pretreatment to overcome the recalcitrance of the biomass for enzymatic conversion. Evident morphological, structural, and chemical changes were observed by scanning electron microscopy, X-ray diffraction, and infrared spectroscopy after pretreatment. High glucan (>90% for both leaflets and rachis) and xylan (>75% for leaflets and >79% for rachis) recovery were achieved. Under the optimal condition of hydrothermal pretreatment (210°C/10 min) highly digestible (glucan convertibility, 100% to leaflets, 78% to rachis) and fermentable (ethanol yield, 96% to leaflets, 80% to rachis) solid fractions were obtained. Fermentability test of the liquid fractions proved that no considerable inhibitors to Saccharomyces cerevisiae were produced in hydrothermal pretreatment. Given the high sugar recovery, enzymatic digestibility, and ethanol yield, production of bioethanol by hydrothermal pretreatment could be a promising way of valorization of date palm residues in this region.

Palm rachis microfibrillated cellulose and oxidized-microfibrillated cellulose for improving paper sheets properties of unbeaten softwood and bagasse pulps

Bleached palm rachis pulp, pretreated with xylanase enzymes, was used for isolation of microfibrillated cellulose (MFC) and TEMPO-oxidized MFC (TMFC) by ultrafine grinding. The isolated MFC and TMFC were used at ratios from 2.5% to 20% for improving strength properties of paper sheets prepared from unbeaten softwood and bagasse pulps. The retention of microfibrillated cellulose in paper sheets was also estimated. The results showed that MFC or TMFC brought about an increase in density, wet and dry tensile strength, tear resistance, and a decrease in air permeability of paper sheets prepared from unbeaten softwood or bagasse. However, usual beating of softwood fibers was much more effective in improving strength properties of softwood paper sheets than addition of microfibrillated cellulose. On the other hand, the improvement in strength properties of bagasse paper sheets as a result of MFC or TMFC addition was generally higher than that resulted from beating of bagasse pulp. Use of TMFC with unbeaten softwood or bagasse fibers resulted generally in better improvement in tensile strength (wet and dry) than in case of using MFC.

Chemical Characterization of Phoenicicole Biomass Fuel in Algerian Oasis: Deglet Nour and Ghars Cultivars Case

The date palm tree (Phoenix dactilyfera L.) constitutes an interesting and dominant resource of biomass fuel in the oasis eco-system due to its several assets (availability, biodiversity, renewable aspect, significant energy potential). A feasibility study of energy recovery from this valuable biomass requires an accurate and thorough knowledge of all its components. This study aims to chemical characterization of the phoenicicole biomass to better apprehend the process of energy extraction. The main biomasses considered in the current work are two dominant date palm cultivars (Deglet Nour (DN) and Ghars GH) in the Guerrara oasis (Algeria). The date palm tree phoenicole byproducts are of a particular interest namely fibrilium (LIF), palms (DJ), date palm petiole (KER), fruit bunch (ARJ), spathe (KH), date palm rachis (AD), and fruit stalk pruning (SA). The approach followed to determine the chemical composition of the considred biomasses is based on thermochemical transformation. This includes the proximate analysis (moisture, ash, volatile matter, and fixed carbon content), the ultimate analysis (C, H, N, S, and O composition) and the calorimetry (higher heating value HHV). To complete this experimental study, we computed the elementary composition and the calorific value using numerical models. An analysis of the links between these parameters was also conducted. Through the study of approximate composition it has been found that the moisture content is relatively small and ash concentration varies between the studied cultivars and their byproducts. Typical found value varies between 5 to 20%. The energetic aspect of the studied phoenicicole biomass indicated an appreciable calorific value of all samples (18 MJ/kg), except fibrilium part, which presented lower values (15 MJ/kg). In addition, the energy value of biomass of DN cultivar is greater than that of GH cultivar. The elementary composition CHO analysis shows a big compatibility of the studied biomass with conventional biofuel feedstock mainly agricultural waste and wood. The analysis of S and N contents shows low values (<0.2% and <0.4%, respectively), which exhibits a very advantageous characteristic for the studied biomass. Finally, the comparison between the HHV measured and the computed values is not satisfactory (average error around 10%), this study identified the application limit of the four models for HHV calculated from the proximate composition. While the calculation of the elementary composition reveals good results for the studied parts (average error around 2%) whose ash content does not exceed 11%.

Physical-chemical Characterization of Lignocellulosic Materials of Interest to Bioethanol Production

The knowledge of the chemical composition of biomass feedstocks is very important in order to decide what lignocellulosic material to be used in the industrial process and the associated pretreatment to bioethanol production. In this context, the present work applied an analytical methodology of chemical characterization, developed for sugarcane bagasse, to other biomasses, namely, sugarcane straw, bamboo, bean stalk, residue from the extraction of castor oil, sape grass, wheat straw, African palm rachis, elephant grass and Agave tequilana. Chemical composition (cellulose, hemicellulose and lignin) of the raw materials was determined by the acid hydrolysis (H2SO4 72%) of theses extractives-free materials. Carbohydrates, organic acids and degradation products were determined by HPLC. Lignin and phenolics were analyzed by gravimetry and spectroscopy procedures, respectively. Results showed that, among the materials studied, the sugarcane bagasse had the higher amount of cellulose (43.8%) and the sugarcane straw had the higher amount of hemicellulose (32.4%) justifying the interest of apply these biomasses as raw materials for the production of cellulosic ethanol. Other biomasses presented cellulose composition varying between 31.8 and 41.7 %, hemicellulose between 21.2 and 28.6 %, and lignin from 20.6 to 33.6 %. Extractives showed more abundant in sape grass (18.7 %) and were removed before the composition analysis to avoid interferences in lignin quantification.

Evaluation of date palm residues combustion in fixed bed laboratory reactor: A comparison with sawdust behaviour

Combustion tests of five date palm Tunisian residues, namely: Date Palm Leaflets (DPL), Date Palm Rachis (DPR), Date Palm Trunk (DPT), Date Stones (DS) and Fruit-stalk Prunings (FP), were performed in a laboratory scale furnace. Gaseous emissions such as CO2, CO, VOC, NOx and SO2, were analysed at 600 °C under 30–60 NL/h flow rate. Obtained results were compared with sawdust combustion behaviour in order to select the most convenient biofuel for an application in domestic boiler installations.Combustion tests show that ignition delay and combustion time reaction are independent of the date palm residue. However, gaseous products emission rates and factors are correlated to the sample characteristics such as carbon, nitrogen and sulphur contents as well as fixed carbon and volatile matters contents. In order to optimize date palm residues combustion by decreasing unburnt gaseous emissions, special attention should be given to the design of the secondary air supply.

Particleboards production from date palm biomass

Date palm biomass is a renewable natural resource that has not widely been utilized in industry. The objective of this study was to examine some chemical properties of date palm trunk and rachis (holocellulose, cellulose, lignin and extractives) and to evaluate their suitability to produce composite panels. Particleboards were produced using trunk and rachis as an alternative raw material for forest products industry in the presence of two types of polycondensation resins (phenol–formaldehyde and melamine urea–formaldehyde) which were selected as binding agents. The panels were tested for their physical (water absorption and thickness swelling) and mechanical (modulus of rupture, modulus of elasticity and internal bond strength) properties. The internal bond strength of date palm trunk and date palm rachis based boards met the requirements of the general purpose product standards (EN 312) at 0.70 g/cm3 density. The panels made with phenol–formaldehyde resin showed better performance with respect to the panels made with melamine urea–formaldehyde. In addition, the particleboard made with date palm trunk particles had better quality compared to the particleboard made from date palm rachis particles. Based on preliminary results of this work, raw materials from date palm trunks and rachis can have a promising potential in the manufacture of particleboards and as a substitute for wood in board production.

Experimental investigation on gaseous emissions from the combustion of date palm residues in laboratory scale furnace

Emissions characteristics from the combustion of five date palm residues, DPR, (Date Palm Leaflets, Date Palm Rachis, Date Palm Trunk, Date Stones and fruitstalk prunings) in a laboratory scale furnace were investigated. Release of gaseous products such as CO2, CO, VOC, NOx and SO2 were measured at 600–800°C. The main goal was to analyze thermal behaviors and gaseous emissions in order to select the most convenient biofuel for an application in domestic boiler installations. Regards to biofuel characteristics, date stone have the highest energy density (11.4GJ/m3) and the lowest ash content (close to 1.2%). Combustion tests show that among the tested date palm residues, date stone may be the promising biofuel for the design of combustion processing system. However, a special attention to the design of the secondary air supply should be given to prevent high emissions of CO and volatile matters.

Study on the thermal behavior of different date palm residues: Characterization and devolatilization kinetics under inert and oxidative atmospheres

Date palm residues are an attractive source of biomass energy since they are renewable, abundantly available and do not compete with food crops. Pyrolysis and combustion may be efficient methods of exploiting energy from these biomass resources. The purpose of this research was to investigate the thermal behavior of date palm biomass in order to evaluate their usefulness for energy production. In fact, ultimate and proximate analyses as well as thermal behavior of different date palm residues (date palm leaflets (DPL), date palm rachis (DPR), date palm trunk (DPT), date stones (DS) and fruitstalk prunings (FP)) were investigated. Non-isothermal thermogravimetric analyses (TGA) were performed to assess fuel reactivities under inert and oxidative atmospheres. Thermal degradation of all samples has exhibited quite similar behavior except DS. In contrast, different properties (e.g., reactivity, HHV or activation energy) were obtained, which may be attributed to a difference between tree parts composition (branches, trunk, fruit…). Thus, DPT and FP were found to be the most reactive materials in inert conditions; while in oxidative conditions, DPR is the highest one. In addition, activation energies corresponding to devolatilization regions under inert and oxidative conditions were 49.8, 45.2, 52.7, 50.9, 89.1 kJ mol−1 and 58.9, 49.6, 67.6, 57.7, 110.7 kJ mol−1 for DPL, DPR, DPT, DS and FP respectively. The obtained data, sample properties along with thermal behavior under inert and oxidative atmospheres as well as kinetic parameters, allowed the comparison of the obtained results with other biofuels and can be useful for the design of processing system for energy productions.

Cellulose fibers obtained by organosolv process from date palm rachis (Phoenix dactylifera L.)

In this preliminary study, the chemical composition of Tunisian DPR was established and discussed. The main characteristic of this agri-residue was its high lignin content in comparison with that of alfa plant. CIMV process was used to selectively separate cellulose fibres, hemicelluloses and lignin at atmospheric pressure. The obtained unbleached pulp was analysed in accordance with Kappa index and degree of polymerisation and then bleached by treating successively with peroxyacids and hydrogen peroxide in basic media.

Inoculation of &lt;i&gt;Bacillus sphaericus&lt;/i&gt; UPMB-10 to Young Oil Palm and Measurement of Its Uptake of Fixed Nitrogen Using the &lt;sup&gt;15&lt;/sup&gt;N Isotope Dilution Technique

There are increasing applications of diazotrophic rhizobacteria in the sustainable agriculture system. A field experiment on young immature oil palm was conducted to quantify the uptake of N derived from N2 fixation by the diazotroph Bacillus sphaericus strain UPMB-10, using the 15N isotope dilution method. Eight months after 15N application, young immature oil palms that received 67% of standard N fertilizer application together with B. sphaericus inoculation had significantly lower 15N enrichment than uninoculated palms that received similar N fertilizers. The dilution of labeled N served as a marker for the occurrence of biological N2 fixation. The proportion of N uptake that was derived from the atmosphere was estimated as 63% on the whole plant basis. The inoculation process increased the N and dry matter yields of the palm leaflets and rachis significantly. Field planting of young, immature oil palm in soil inoculated with B. sphaericus UPMB-10 might mitigate inorganic fertilizer-N application through supplementation by biological nitrogen fixation. This could be a new and important source of nitrogen biofertilizer in the early phase of oil palm cultivation in the field.

Measurement of Gaseous and Particulate Pollutants during Combustion of Date Palm Wastes for Energy Recovery

Being an important date-producing country, Tunisia generates high quantities of dry date palm residues which are currently not efficiently used, and instead accumulate every year in oasis lands. These by-products could present real advantages for Tunisia for energy production in both economic and environmental terms. Heating installations using biomass generate primary pollutants, such as CO, VOC and Particle Matter (PM), these latter having the most important adverse impact on environment. Measurements of these pollutants are needed, because international certification organizations require drastic limits on CO and PM emissions from biomass combustion processes. In this study, date palm leaflets (DPL), date palm rachis (DPR), date palm trunks (DPT) and date stones (DS) were combusted in a laboratory scale mobile furnace. The aim of this work was to find an appropriate of these materials for energy recovery, with low emission factors of gaseous and PM in the exhaust. Combustion tests were performed at two temperatures (500°C and 800°C) and input air flow rates (25 and 50 NL/h). With the lowest content of chlorine and the highest bulk and energetic densities, DS is the most convenient date palm residue for energy recovery. Combustion of DPL, DPR and DPT needs to be performed at high temperature to obtain a complete carbon balance, and this is not required for the combustion of DS, which has a value of 88% for the carbon balance at 500°C. Particles emitted during combustion are mainly constituted of fine and ultrafine particles. For all samples, 99% are particles with diameters below 1 μm. Combustion of DS produces the lowest content of PM0.1, leads to the lowest emissions factors of aerosols, and generates fewer tars than the other date palm by-products. An increase in the input air flow rate, and therefore decrease in the residence time during combustion of DS, generates a larger amount of aerosols.

Occurrence of Some Fungal Diseases on Date Palm Trees in Upper Egypt and its Control

In 2007, date palm trees surveyed for different symptoms on leaves and fruits in Upper Egypt. The samples were collected from symptomatic rachis, fronds and fruits in four localities (El-Minia, Assiut, Sohag and Qena Governorates). The major diseases noticed were leaf spots, off-shoot decline, black scorch, leaf basal rot and fruit spots. Seven different fungal species were isolated from date palm exhibited different symptoms. The results of pathogenicity test proved the ability of Thielaviopsis paradoxa, Alternaria alternate and Negrospora oryza to infect date palm rachis, fronts and fruits, respectively. Helminthosporium sp. and Epicocum nigrum were associated with the leaf spots. E. nigrum was associated with off-shoot decline, black scorch and leaf basal rot, while Fusarium proliferatum and Aspergilus niger were associated with fruit spots. Antagonistic effect of E. nigrum against A. alternate and T. paradoxa was examined by dual culture technique which leads to clear inhibition zone. Calcium chloride (CaCl2) and E. nigrum filtrates effectively controlled the leaf spot (as major disease) when applied at suitable time (when disease severity was low).

Sodium carboxylmethylate cellulose from date palm rachis as a sizing agent for cotton yarn

The chemical composition of date palm rachis wastes, which are widely available cellulosic biomass-based agricultural crops in Tunisia, were characterized to determine if they had the potential for use as a starting raw material to prepare cellulose derivatives. To accomplish this, several sodium cellulose carboxylmethylates (NaCMCs) were prepared and tested as sizing agents for coating yarn. The synthesis of NaCMC was conducted in n-butanol containing NaOH (40 %) as a solvent mixture and monochloroacetic acid (MAC) as the etherifying reagent. The NaCMC samples were characterized based on their degrees of substitution (DS) and polymerization (DP). The prepared NaCMC samples were then tested as sizing agents for cotton yarn in textile applications. Specifically, different NaCMC samples were used to prepare a coating bath, which was then applied to size a cotton yarn textile. The quality of the coated yarns was subsequently evaluated by determining three parameters, yarn hairiness, the load at break, and the elongation at break. The sizing performances of the NaCMCs prepared from date palm rachis wastes were then compared with those of commercial NaCMC. The values of hairiness, breaking load, and breaking elongation of some of the NaCMC-treated yarns were as high as those prepared using commercial additives as sizing agents. These findings indicate that the cellulose derivatives prepared in this study are good candidates for alternatives to currently available additives.

Tunisian date palm rachis used as an alternative source of fibres for papermaking applications

Every year, significant amounts of date palm rachises are accumulated in Tunisia. The rational valorisation of this renewable resource is therefore imperative, in order to fulfil the sustainability approach. In this context, this work aims to study the potential use of date palm rachises as a raw material for papermaking and to compare it with other sources of lignocellulosic fibres, such as wood, non-wood species, and agricultural wastes. For this purpose, soda-anthraquinone pulping of date palm rachis was performed giving rise to a yield of 45% (w/w). This value is similar to that obtained by pulping non-wood materials and is higher than that corresponding to the pulping of agricultural residues. The resulting pulps were subsequently refined using a PFI mill refiner at 0, 500, 1500, and 3000 revolutions, screened through a 0.15 mm mesh size sieve and used to produce conventional handsheets. Both pulps and papers were fully characterized in terms of morphological, chemical and physical properties, according to commonly used standards. The physical properties of the prepared handsheets were very similar to those displayed by other papers made of common lignocellulosic fibres. Furthermore, the pulps exhibited a good drainability together with excellent mechanical properties of the ensuing papers. For these reasons, date palm rachises could be considered as a potential source of fibres for papermaking applications.

Experimental evaluation of eco-friendly flocculants prepared from date palm rachis

Sodium carboxymethylcellulose (CMCNa) is an anionic water soluble polyelectrolyte widely used in many industrial sectors including food, textiles, papers, adhesives, paints, pharmaceuticals, cosmetics and mineral processing. CMCNa was produced by chemical modification of cellulose, and represents many advantages: natural, renewable, non-toxic and biodegradable. In this study, different kinds of CMCNa, prepared from an agricultural waste date palm rachis, were tested as eco-friendly flocculants for drinking water treatment and their performances as flocculants in turbidity removal enhancement were assessed. The prepared materials were characterized by the degree of substitution (DS) and polymerisation (DP). The study of the effect of some experimental parameters on the coagulation-flocculation performance, using the prepared materials combined with aluminium sulphate (as coagulant), showed that the best conditions for turbidity treatment were given for pH 8, coagulant dose 20 mg/L, flocculant concentration of 100 mg/L and stirring velocity (during the flocculation step) of 30 r/min. Under the optimum conditions, the turbidity removal using CMCNa, prepared from raw material, was about 95%. A comparison study between the flocculation performance of a commercial anionic flocculant ( A 100PWG: polyacrylamide) and that of the prepared CMCNa showed that the performance of the waste-based flocculant with a DS of 1.17 and a DP of 480 was 10% better than that achieved by the commercial one.

Valorisation of Vegetal Wastes as a Source of Cellulose and Cellulose Derivatives

Different qualities of CMC were prepared from an agricultural residue (date palm rachis) and a marine waste (Posidonia oceanica). These starting lignocellulosic materials were used as such and after chemical pulping and bleaching. The carboxymethylation reaction was carried out in presence of NaOH (40%) and monochloroacetic acid (ClCH2COOH, MAC), in n-butanol as the reaction solvent. The substitution degrees (DS) of the obtained CMCs varied from 0.67 to 1.62 and between 0.98 and 1.86, for P. oceanica and date palm rachis, respectively. The CP-MAS 13C-NMR spectra of the prepared polyelectrolytes displayed the presence of the main peaks associated with cellulose macromolecules (C1–C6) and that corresponding to carboxyl functions at around 175 ppm. Unfortunately, the peak attributed to methylene groups neighbouring carboxyl moieties are overlapped by C2 and C3, which renders them hardly detectable. Nevertheless, it is worth noting that the CP-MAS 13C-NMR spectra revealed the presence of different signals originating from residual impurities (ca. 27 ppm), such as traces of lignin macromolecules (110–150 ppm) and methyl groups attributed to hemicelluloses. Work is in progress to establish a more efficient purification procedure, in order to have more accurate values of DS.

Chemical composition and pulping of date palm rachis and Posidonia oceanica – A comparison with other wood and non-wood fibre sources

In the present paper, the valorisation of two residues: Posidonia oceanica and date palm rachis was investigated. First, their chemical composition was studied and showed that they present amounts of holocellulose, lignin and cellulose similar to those encountered in softwood and hardwood. Extractives in different solvents and ash contents are relatively high. Moreover, ash composition assessment showed that silicon is the major component (17.7%) for P. oceanica. The high ash quantity and the low DP (about 370) may be considered as serious disadvantages of P. oceanica, in the pulping and papermaking context. Oppositely, the properties of rachis date palm and those of the ensuing pulp, obtained from a classical soda-anthraquinone cooking, demonstrated the suitability of this agricultural by-product for papermaking. Preliminary tests conducted on unrefined pulp suspensions and handsheets from date palm rachis in terms of freeness, Water Retention Value and mechanical properties allowed confirming the good quality of date palm rachis fibres.

Paddy dehydration by adsorption: Thermo-physical properties and diffusion model of agriculture residues

Dehydration of high-moisture grain kernels using adsorption is an interesting method, especially when agricultural residues are used as adsorbents. This dehydration method is a low-temperature drying process that is simple, requires no mechanical equipment, has low energy consumption and maintains grain quality. The aim of this research was to investigate the use of rice husk, coconut husk and sago palm rachis to reduce the moisture content of fresh paddy. The thermo-physical properties and the drying kinetics of these agricultural residues acting as moisture adsorbents were studied. The bulk density, specific heat capacity, void fraction, equilibrium moisture content (EMC) and the effective diffusion coefficient (Deff) of the adsorbents were determined. The bulk density, specific heat capacity and void fraction were determined at initial moistures contents ranging from 4.1% to 72.4% dry-basis (d.b.). The EMC and Deff values were measured at surrounding temperatures and relative humidity varying from of 40 to 70 °C and from 10% to 90%, respectively. For evaluating the Deff value using thin-layer drying (TLD), an experiment was carried out at inlet air temperatures of 30–70 °C. The bulk density and specific heat capacity of all three adsorbents were linearly dependent on the moisture content and the void fraction was inversely related to the moisture content. The four commonly cited EMC equations were fitted to the experimental data. A modified Henderson equation provided the best fit for describing the EMC isotherm of all the study cases. The modified Henderson and Pabis model provided a good fit to the experimental TLD results and the Deff values, determined by non-linear regression, were significantly affected by the inlet drying air temperature. The Deff values were in the range 1.2×10−8–6.2×10−8 m2 s−1. Sago palm rachis had the highest Deff value compared to coconut husk and rice husk. However, the most suitable adsorbent material was rice husk because it was easy to prepare and it could be regenerated by low-temperature heating.

Alkaline pulping with additives of date palm rachis and leaves from Sudan

Soda-anthraquinone (soda-AQ), alkaline sulphite-anthraquinone (AS-AQ) and alkaline sulphite-anthraquinone-methanol (ASAM) pulping of date palm rachis and leaves from Sudan was carried under different conditions, and pulps with variable yields and mechanical properties were obtained. The date palm rachis gave best yields and mechanical properties with the AS-AQ or the ASAM process, while the leaves were best pulped with the soda method with low yield, but very good strength properties. Blending with 10% and 30% kenaf bark pulp was beneficial, especially for the AS-AQ pulps. Totally chlorine free (TCF) bleached rachis pulps were obtained of high brightness and strength properties suitable for use in writing and printing papers.