Cassava Stalk Research Articles

Pyrolytic Characteristics and Kinetic Parameters Evaluation of Cassava Stalks Using Thermogravimetric Analyzer

Pyrolytic characteristics and kinetics of cassava stalks as a renewable energy source were delved via a thermogravimetric (TG) analyzer. About 10 mg powder of the sample was heated up in the TG cavity under inert conditions with 50 ml.min-1 nitrogen flow rate and operated at 20 °C min-1 of heating program. The pyrolysis process of cassava stalks was taken place into three main stages, in which the peak reaction occurred at the second stage with 70% of the mass was degraded. The differential method of Arrhenius kinetic evaluation resulted in the values of reaction order (n) that was 0.99, activation energy that was 89.46 kJ/mol and logarithmic frequency factor (log A) was 7.7 min-1.

Process design for bioconversion of cassava stalk through solid substrate fermentation

Cassava stalks are by products from cassava tuber production. Cassava stalks is lignocellulosic material (LM) which is composed by lignin, hemicelullose, and cellulose. Utilization of LM optimally will push a beneficial effort in producing sugar. The presence of lignin can limit the effort to convert cassava stalks into sugar. The lignin have to be reduced. Its introduced solid substrate fermentation (SSF) technique by using molds to optimize utilization of cassava stalks. Molds can produce enzyme for converting LM into sugar. There is no enough information of design process of solid state fermentation for cassava stalks bioconversion, starting from selection of suitable microorganism used, substrate suitability testing, lignin reducing pretreatment, design of fermentor, and the needed of aeration for optimizing molds growth. Based on research result, a process for bioconversion of cassava stalks into sugar through SSF techniques was defined as follow: Microorganism suitable used is Aspergillus niger, cassava stalks suitable as a growth media for mold as a physical support (DMC = 93, 76 %) and source of nutrient (C/N 19, 92), physical pretreatment by reduce the particle size was more suitable than alkaline pretreatment for lignin reduction, and the best fermentor is unforced aeration closed chamber at big capacity.

Cassava- and bamboo-derived carbons with higher degree of graphitization for energy storage

Biomass-derived carbons are among the most promising candidates for large-scale electrochemical-energy-storage devices owing to their low cost, sustainability and widespread resources. Herein, the authors report a simplistic synthesis process for preparing two types of biomass carbons derived from cassava stalks and bamboo consisting of direct pyrolysis of the ground samples at 750°C for 4 h. The electrochemical performances of the prepared biomass carbons are investigated in supercapacitors and lithium-ion battery (LIB) systems. Both the cassava and bamboo samples possess a high graphitization degree and good surface wettability as demonstrated by X-ray diffraction, Raman spectroscopy and Fourier transform infrared spectroscopy. As a supercapacitor electrode, cassava-derived carbons show the best performance with a maximum specific capacitance of 212 F/g and capacity retention of 95% after 2000 cycles. Moreover, as an electrode material for LIBs, cassava-derived carbons demonstrate the highest charge capacity of 357 mAh/g (at 100 mA/g), which stabilizes at 254 mAh/g. This approach shows great potential to achieve advanced electrode materials from low-cost, green and industrial-grade production of biomass-derived carbon materials by simple synthesis for advanced energy-storage applications in the future compared with conventional approaches.

Commercial viability of integrated waste treatment in cassava starch industries for targeted resource recoveries

The commercial viability of an integrated waste treatment process for converting wastewater and bagasse from a 200 t/d cassava starch facility, together with the associated cassava stalks, into bioenergy products and biofertilizer coupled with recovery of water for reuse, was assessed using Aspen Plus® simulations. The wastewater and bagasse are anaerobically digested for producing biogas that is combusted for thermal energy (Case I), or augmented with CS for combined heat and power production via steam boiler and turbo-generator while recovering biofertilizer in liquid or solid form (Cases II and III). In Case I, the biogas produced meets the thermal energy needs for starch drying in the cassava starch facility. Case II demonstrates energy self-sufficiency for the combined heat and power process and generates 28.53 MW as surplus power that is adequate for meeting power demands from the starch facility (∼2.17 MW) whereas, Case III generates only 56.5% of the biorefinery’s total power demands. In addition, liquid biofertilizer is recovered in Cases I and II while Case III allows for recovery of solid biofertilizer as well as water for reuse in the combined heat and power production, thus reducing the demand for freshwater by 66%. All three cases present potential profitable commercial investment with Net Present Values between US$ 83.4 million and 130 million, depending mainly on wastewater treatment costs and bioelectricity prices, and minimally on biofertilizer and thermal energy prices. Thus, the integration of water recovery and cassava stalks conversion into cassava waste treatment results in both economic and environmental benefits for the cassava starch industries.

Economic and Energy Valorization of Cassava Stalks as Feedstock for Ethanol and Electricity Production

Cassava (Manihot esculenta) is a woody bush extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy tuberous root, a major source of carbohydrates. The main residue from its cultivation is the cassava stalk, which is normally used as soil fertilizer or in culture propagation. The main goal of this paper is to evaluate two routes (biochemical and thermochemical) for bioenergy production (ethanol and synthesis gas—electricity) using cassava stalk as raw material. A detailed techno-economic and energy assessment is carried out based on the simulation approach of both conversion routes to determine the production costs of main products and the overall energy efficiency of the processes. The electricity production costs vary from 0.008 to 0.037 USD/MJ, whereas the ethanol production costs range from 1.11 to 2.02 USD/L (including subsidies). The change in the production costs was observed due to the assumptions of the model, e.g., cassava stalk, transportation, and enzyme costs. The overall energy efficiency of the gasification and ethanol fermentation was 68.7 and 25.1%, respectively.

The Amount of Cassava Tuber Remained on Underground Stem after Chopped with Various Cross-Section and Diameter of Cylinder Blades

This study aims to test and compare the amount of cassava tubers which remained with underground stem after chopped with cylinder blades which had different cross-section and sizes (3x3 Treatments) by using “Kasetsart 50 cassava variety” with the age of 8 months old that planted in sandy loam in Kalasin Province. There are 30 cassava stalks per treatment were used as the sample. The implement of the test was Factorial in Completely Randomized Design. The results found that increasing of diameter of the cylinder blade from 6 – 8 cm caused the increasing amount of cassava tuber remained with underground stem, however, average tuber loss was just in range of 2.56-3.36% wt. (p-value = 0.003), but the increasing did not affect the amount of force used in cassava chopper. As for changing the cross section of cylinder blade (Square, Round and Hexagon), it caused changes in the amount of cassava tuber remained with underground stem after chopping, but there was no exact direction (p-value = 0.036). However, changing of cross section would cause changes of cassava chopper force (p-value = 0.001) that its directions were related to the length of perimeter of each cross-section.

Iptek Bagi Masyrakat (IbM) Kelompok Usaha Peternak Ayam & Bebek

One of the efforts that became the target of development in the community by the Simpang Rimba district is chicken and duck farms. This is supported by the large availability of plants that will be used as animal feed such as cassava and taro stalk. However, currently the process of making animal feed is still done manually that is chopped by using a knife or a machete so that the time taken is long and the resulting capacity is limited. The purpose of science and technology for the community of chicken and duck breeders is to increase the production capacity of animal feed up to 100% and the uniformity of the cultivated product increases 100%. The method of implementation used in this service is to make a machine of cattle feed after doing a short training on the operation and maintenance of machinery to partners. Based on the results obtained the use of cassava chopper machine and taro stalk can increase the production process 40 kg within 30 minutes and the thickness of cassava size obtained an average of 2-7 mm so that the percentage of countable can be consumed 100% increase.

Hiệu quả của thay thế mùn cưa cây cao su bằng vỏ tràm trong nuôi trồng nấm vân chi đỏ (Pycnoporus sanguineus (L.: Fr.) Murrill)

The objective of this study was to assess the potential utilization of melaleuca bark for Pycnoporus sanguineus mushroom cultivation. The experiment was carried out in a complete randomized design with 9 treatments (difference in substrate of melaleuca bark replacing rubber sawdust), 3 replications (10 bag/each replication). Results showed that at the first phase of culture (spawn production), mycelium got the fastest develop speed (1.78 cm/day) in the Potato-dextrose-agar (PDA) medium supplemented with 10% coconut water. In the second phase, steamed rice grain was evaluated as the optimal substrate for mycelial growth (0.988 cm/day). In the third phase, boiled cassava stalks was the best medium for mycelial spreading (0.538 cm/day). The compost consisting of combination of 60% melaleuca bark and 40% rubber sawdust was revealed as the most suitable substrate for Pycnoporus sanguineus growth that giving the highest yield (60.1 g/bag) with biological efficient (20%). In conclusion, melaleuca bark have the potential to be utilize as alternate substrate for Pycnoporus sanguineus mushroom cultivation to achieve high efficiency on the compost consisting of combination of melaleuca bark (60%) and rubber sawdust (40%) without nutritional supplement.

Implementation of Species-Transport Model in Numerical Simulation to Predict the Performance of Downdraft Gasifier with Biomass Blends

The demand for energy from biomass gasification is increasing due to the depletion of fossil fuels and serious environmental issues. Due to this, usage of individual biomass in a gasifier is not sufficient to meet the demand in rural areas. However, an enormous study have been reported on the gasifier with single biomass as working fuel. In addition, only a few works have been carried out on biomass blends in a gasifier through equilibrium modelling and experimental approach. The numerical simulation for the biomass blends are in scarce. Hence, in this study, a numerical and experimental studies were conducted on a 40kWth downdraft biomass gasifier to find out the possibility of rubber seed kernel shell and cassava stalk biomass with different blend ratio. The species-transport CFD model is used for numerical simulation with the k-e turbulence model. The effect of species concentration, higher heating value and conversion efficiency with respect to different equivalence ratio have been observed. The simulated results were also validated through experimentation. Among different blending ratio 80:20 blend shows better performance. The result reveals that the species concentration and higher heating value at 0.2 equivalence ratio has an average value of CO-23.5 %, H2-19.2%, CH4-3.1% and 6.62 MJ/Nm3 with an efficiency of 58.23% respectively. The viability of using the species transport model for biomass blends is confirmed.

Effect of Lime Pretreatment on Microstructure of Cassava Stalk Fibers and Growth of Aspergillus niger

Cassava stalk can be converted into sugar-based product by using microorganism. Unfortunately, lignin act as a barrier of optimal bioconversion. Cassava stalk needs pretreatment process for removing this barrier. The effect of lime pretreatment on microstructure of cassava stalk fibers and the growth of Aspergillus niger FNCC 6114 were observed in this research. The cassava stalks were reduced into 0.147- 0.297 mm size and pretreated with 1 % Ca(OH)2. Lime pretreated and unpretreated cassava stalk was used as solid medium for Aspegillus niger FNCC 6114. The effect of pretreatment method on fibers microstructure of cassava stalk was evaluated through SEM micrograph. The growth and metabolism activities of Aspergillus niger FNCC 6114 were monitored through SEM micrograph of media after fermentation. The other parameters examined were changes in glucosamine, reducing sugar levels, and spores’ quantity. Lime pretreatment altered microstructure of cassava stalk fibers. However, cassava stalk without lime pretreatment gave better growth of Aspergillus niger FNCC 6144 based on metabolism activities parameters. Cassava stalks is suitable as media for Aspergillus niger FNCC 6144 through solid state fermentation. For better growth of Aspergillus niger FNCC 6144 fine-sized cassava stalk should not be lime pretreated. The results of this study provide information about the pretreatment of cassava stems which was effective in supporting the growth of Aspergillus niger. Enhancements the utilization of cassava stems by using fungi, for example Aspergillus niger can overcome the accumulation of organic waste that can interfere with environmental sustainability.

Effect of biomass characteristics on durability of Cassava stalk residues pellets

This study aims at investigating the effect of the main biomass characteristics (moisture content and particle size) on durability of Cassava stalk residues pellets. This durability is necessary to consider design of the material handling, processing equipment, storage and transportation of biomass pellets. The raw biomass materials were ground and screened into four range sizes and pelletization was done at three different percentage levels of moisture conditions defined as percentage of added water by mass of raw material. Pellets in each condition were analysed for durability. The result showed that the highest durability occurred in particle size 1.7 mm but less than 3.35 mm and 10% moisture content by mass of raw biomass material. The mean durability in the best conditions was 99.02%. This information is important for the design and efficient preparation of biomass material for pelletization to achieve the high quality pellets with high durability for handling, transportation and storage.

Coupled effect of torrefaction and blending on chemical and energy properties for combustion of major open burned agriculture residues in Thailand

Abstract Thailand is an agriculture-based country. It produces large amounts of open burned agricultural residues. A strategy to use them as biofuel all year round is to enhance their fuel properties by coupling blending and thermochemical pre-treatment. In this study, the pyrolytic behaviour of major residues (napier grass, rice straw, cassava stalks and corn cob) exposed to a high torrefaction temperature (300 °C) was investigated for various blending ratios, i.e. 100:0, 50:50 and 70:30. The release of chlorine was quantified for each biomass blend, including, a new fouling risk index ratio. Also, the synergistic effects of both ignition and burnout temperatures were analysed. Rice starw and napier grass were found to be characterised by a high ash content and so large amounts of solid yield after torrefaction. Raw biomasses and untreated biomass blends were found to be less suitable as biofuel than torrefied biomasses. The ratio K2O:SiO2, indicator of fouling risk during combustion, was found to be low for all torrefied blends. The HHV:Cl ratio, indicator of combustion quality, indicated that NG mixed with RS (50:50 proportion) is the most promising blend. Significant synergetic effects were observed for biomasses mixed before torrefaction. The burnout temperatures for raw and torrefied biomasses were identified in the range 773–787 °C and 786–795 °C.

Farm waste utilization among farmers in Irepodun local government area, Kwara state, Nigeria: implication for extension education service delivery

The study examined the utilization of farm waste among farmers in Irepodun Local Government Area of Kwara State, Nigeria. Structured interview schedule was used to elicit data from 120 farmers in the study area. Results revealed that more than half (58.4%) of the respondents were crop farmers who grow majorly maize and cassava on a subsistence scale. The major farm wastes generated in the area were maize cobs, husk and stalk (62.5%) and cassava stalk and peels (60%). Majority of the farmers got rid of their farm waste through burning while more than half of the respondents do not utilize the waste they generate from their farms. The major constraints militating against farm waste utilization includes inadequate access to extension services, inadequate awareness of benefits of farm waste, inadequate facilities for processing of farm wastes to other products and low knowledge on usage of farm waste. Logistic regression modelling results revealed that farmers who are more likely to utilize their farm waste efficiently are those with higher level of education and more years of experience in farming. It was therefore recommended that extension agencies should embark on enlightenment campaigns and trainings of farmers on various innovative ways of farm wastes utilization in order to facilitate more efficient and environmental friendly farm waste utilization initiatives in the area. Keywords. Assessment, Farmers, Farm Waste, Kwara State, Utilization.

Effect of moisture and region of cut on cassava stalk properties in biomass applications

In an attempt to investigate the potential of using cassava stalk as a biomass material and determine the design requirements for developing a cutting machine, this study aims to investigate physical and mechanical properties of cassavas stalk, under the influence of moisture content and region of cut using statistical techniques. Moisture contents were ranged into three different levels; 54.19, 43.05 and 24.93% wet basis (w.b.) while cutting regions were classified as top (tip of cassava stalk), middle and bottom. Mechanical properties were represented by shearing stress. Physical properties, on the other hand, were represented by length, diameter, and mass. By decreasing moisture levels, all parameter values were reduced, except shearing stress. Moreover, it was found that shearing stress increased when lowering the cutting line. Maximum and minimum shearing stress occurred at bottom and top regions of the stalk, respectively. Most importantly, moisture content and region of cut both had a significant influence (P < 0.05) on shearing stress, although the latter had much larger impact.

Research on the Mechanical Properties of the Cassava Stem

The mechanical properties of the cassava stalk play an important role in the design of cassava harvesting and cassava stalk recycling machines. The mechanical properties were measured and analyzed under compression, shear and bending by physical methods for 205 cassava specimens from southern China. The results showed that the cassava stalk is an anisotropic material, its water content was 68.86% in the cassava harvest season, the mean axial compression strength was 1.51 MPa, mean radial compression strength was 0.76 MPa, the average axial and radial shear strengths were 0.32 MPa and 2.23 MPa, respectively and the radial bending strength was 5.94 MPa.

Copyrolysis energy analysis of municipal solid waste and agricultural stalk

Co‐pyrolysis of municipal solid waste with cassava stalk or corn stalk was investigated in this work. Profiles of the product yields versus different agricultural stalk adding ratios during pyrolysis at 600°C reveal that the char yields reduced, and the liquid and gas yields increased at start‐up stage but afterwards decreased with adding ratios of agricultural stalk increasing. The differences between experimental and theoretical yields of char ranged from 18.26 to 10.35% as cassava stalk ratios from 10 to 50%, and from 8.13 to 11.09% as corn stalk ratios from 10 to 50%. The statistical analysis of theoretical and experimental data implied the synergistic effect between municipal solid waste and agricultural stalk during co‐pyrolysis process. The energy balance showed that pyrolysis of municipal solid waste alone could not produce enough pyrolysis liquid to compensate the energy consumption of pyrolysis system, and the co‐pyrolysis system could dispose of municipal solid waste without extra energy input. The calculated results also showed that the feed stock comprised of 49.21% of cassava stalk or 40.12% of corn stalk could guarantee the energy balance of the co‐pyrolysis system. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 547–552, 2016

Particle boards produced from cassava stalks: Evaluation of physical and mechanical properties

We investigated the potential use of cassava stalks for the production of bonded particle boards. Particle boards were produced from cassava stalks using urea-formaldehyde as a binder. Water absorption and thickness swelling tests were carried out to determine dimensional stability of the boards while modulus of rupture and modulus of elasticity tests were carried out to assess the mechanical strength of the boards. Particle boards produced using an adhesive–cassava stalk ratio of 3:1 gave the best results in terms of the lowest mean values of water absorption (20%) and thickness swelling (6.26%), as well as the highest values of modulus of rupture (4×106 N/m2) and modulus of elasticity (2366.74×106 N/m2). The particle boards produced met the ANSI/A208.1-1999 standard for general-purpose boards. The results of analyses of variance carried out revealed that the adhesive–cassava stalk ratio had a marked influence (p<0.05) on the physical properties (water absorption and thickness swelling) but not on the mechanical properties (modulus of rupture and modulus of elasticity).

Enzymatic hydrolysis of cassava stalks pretreated with the alkaline method

This study was developed with the aim of evaluating the pH, enzymatic complex load and temperature effects on the saccharification of pretreated cassava stalks (CS) using the response surface methodology (RSM). The factor levels evaluated were temperature 35-40°C, pH 4.0-5.0 and dose of enzymatic complex Accellerase 1500™ 2.9 - 14.5 FPU/g of substrate. The reducing sugar (RS) response was used. The pH was controlled through the use of hydrochloric acid and sodium hydroxide solutions and the system was shaken orbitally at 120 rpm with a solids loading of 10% w/v. The fitted model showed that the optimal operating conditions were: pH 4.0, 38°C and enzyme dose of 14.5 FPU/g substrate, reaching a sugar concentration of 18.4 g L-1.

Pyrolysis Characteristics and Kinetics of Cassava Residues

The aims of this work were to investigate the influence of feedstock properties of different part of cassava residues (cassava rhizome (CR), cassava stalk (CS) and cassava leaf (CL)) and operating temperatures on the pyrolysis characteristics and the kinetic parameters. Pyrolysis experiments of three selected biomass feedstock were conducted using a fixed-bed reactor. It was shown that the bio-oil yield of cassava stalk reached the maxima at 600°C, and the char yield reduced with the temperature, whereas the gas yield increased with temperature. The cassava rhizome presented higher thermochemical reactivity than the other samples. The activation energy of cassava stalks was 37.57 kJ / mol and that of cassava rhizome (39.42 kJ / mol) increased slightly. The activation energy of cassava leaf (22.85 kJ / mol) was lowest of the three samples.

Compositional analysis and projected biofuel potentials from common West African agricultural residues

In recent years the focus on sustainable biofuel production from agricultural residues has increased considerably. However, the scientific work within this field has predominantly been concentrated upon bioresources from industrialised and newly industrialised countries, while analyses of the residues from most developing countries remain sparse. In this study the theoretical bioenergy potentials (bioethanol and biogas) of a spectrum of West African agricultural residues were estimated based on their compositions. We analysed 13 of the most common residues: yam peelings, cassava peelings, cassava stalks, plantain peelings, plantain trunks, plantain leaves, cocoa husks, cocoa pods, maize cobs, maize stalks, rice straw, groundnut straw and oil palm empty fruit bunches. The yam peelings showed the highest methane and bioethanol potentials, with 439 L methane (kg Total Solids)−1 and 0.61 L bioethanol (kg TS)−1 based on starch and cellulose alone due to their high starch content and low content of un-biodegradable lignin and ash. A complete biomass balance was done for each of the 13 residues, providing a basis for further research into the production of biofuels or biorefining from West African agricultural residues.