Low Volatile Matter Research Articles

Engineered biochar produced through microwave pyrolysis as a fuel additive in biodiesel combustion

Fossil fuels produce greenhouse and harmful gases that have negative impacts on human health and the environment. This study was devoted to producing biochar through microwave pyrolysis at 700 W for 10–30 min and examining the use of biochar as a fuel additive to mitigate harmful gas emissions and improve the overall combustion efficiency. The biochar obtained showed high fixed carbon content (85.7 wt%), low volatile matter (8.4 wt%), and low ash content (2 wt%) and was subsequently used as a fuel additive in biodiesel combustion. The addition of biochar to biodiesel increased the overall combustion efficiency, owing to the oxygenated compounds present in biochar. The post-combustion emissions of the blended fuel showed a lower emission of carbon monoxide and nitrogen oxide, by up to 20 and 3 folds, respectively, compared to that of baseline fuel. This study showed that oxygenated biochar could be used as an additive to increase the combustion efficiency of biodiesel. The platform developed herein could serve multiple objectives of valorizing biomass into a value-added product and mitigating the harmful emissions associated with biodiesel combustion. The latter could enhance the environmental sustainability of this biofuel.

Comprehensive experimental study on energy conversion of household kitchen waste via integrated hydrothermal carbonization and supercritical water gasification

In China, huge amount of household kitchen waste (HKW) is generated, and it is difficult to be treated due to its complex organic composition and high moisture. Hydrothermal technique can directly convert organic matters into hydrochar or syngas based on the operating conditions. In this study, a two-stage energy recovery process by integrating hydrothermal carbonization (HTC) and supercritical water gasification (SCWG) was used for HKW treatment. Firstly, HKW was processed by HTC at various temperatures (200–300 °C), producing hydrochar and HTC derived liquid. Energy densified hydrochar (20.63 MJ/kg), highest fixed carbon, and lowest volatile matter was obtained at 300 °C and 75 min residence time of HTC. HTC derived liquid containing rich organic content was sequentially converted to H2-rich syngas by SCWG. Highest H2 yield of 3.94 mol/kgHKW was produced at optimal condition (300 °C, 75 min HT – 480 °C, 20 min SCWG). The comparison of integrated process (HTC + SCWG) with direct SCWG were discussed, the lowest energy efficiency (8.99%) and return on energy investment (25.55%)) was obtained in direct SCWG. Cost benefit ratio of 1.86 implied that integrated process is an economically feasible. Therefore, energy recovery process can be a promising method for disposal and utilization of HKW.

Valorization of Hemp Stalk Waste Through Thermochemical Conversion for Energy and Electrical Applications

The presented research aimed at finding new ways to value hemp by-products (stalks) from the cannabidiol industry through thermochemical conversion. Chemical and elemental composition of hemp biomass was investigated by successive chemical extractions and Scanning Electron Microscopy along with Energy-dispersive X-ray Spectroscopy. Proximate and elemental analyses completed the chemical characterization of the hemp biomass and its biochar. Thermogravimetric analysis of the hemp biomass allowed to understand its kinetic of decomposition during thermal conversion. The carbon structure and porosity of the biochar were assessed by Raman spectroscopy and CO2 gas adsorption. Properties of interest were the energy production measured through calorific values, and the electrical conductivity. Two ways of valorisation of the hemp biomass were clearly identified, depending mainly on the chosen pyrolysis temperature. Hemp biochar carbonized at 400–600°C were classified as lignocellulosic materials with a good potential for solid biofuel applications. Specifically, the resulting carbonized biochar presented low moisture content (below 2.50%) favourable for high fuel quality, low volatile matter (27.1–10.4%) likely to show lower particle matter emissions, limited ash content (6.8–9.8%) resulting in low risk of fouling issues during the combustion, high carbon content (73.8–86.8%) suggesting strong energy density, associated with high higher heating values (28.45–30.95 MJ kg−1). Hemp biochar carbonized at 800–1000 °C displayed interesting electrical conductivity, opening opportunities for its use in electrical purposes. The electrical conductivity was related to the evolution of the biochar microstructure (development of graphite-like structure and changes in microporosity) in regard with the thermochemical conversion process parameters.Graphical abstract

Optimization of rice husk hydrochar via microwave-assisted hydrothermal carbonization: Fuel properties and combustion kinetics

The optimization of rice husk hydrochar was carried out via microwave-assisted hydrothermal carbonization to find the optimum parameters for hydrochar production. Three optimized hydrochar was selected to find the best properties for solid biofuel application. The percentage difference between predicted and experimental values was below 10% for all optimized hydrochar. Hydrochar B (optimized for maximum high heating value) has the highest fixed carbon (29.86%), lowest volatile matter (54.6%), lowest ash (8.87%) and highest higher heating value (18.9 MJ/kg) compared to raw rice husk, hydrochar A (maximum solid yield) and hydrochar C (maximum solid yield and higher heating value). The result suggests that the optimized hydrochar produced is comparable to lignite and can be used as direct solid biofuel.

Preparation and characterization of carbon black (CB) using heavy residue fraction of spent tyre pyrolysis oil

In the interest of utilisation of industrial waste products, this paper investigated the preparation and characterization of carbon black (CB) made via partial oxidation of a heavy residue fraction (HRF) of spent tyre pyrolysis oil in a drop tube furnace. The effect of process temperature, residence time (Rtime), and O2 concentration on the yield and quality (elemental composition, functional groups, morphology, thermal behavior, and surface area) of HRF-CB were determined using elemental analyzer (EA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), thermogravimetric analyzer (TGA), and Brunauer-Emmett-Teller (BET) nitrogen adsorption/desorption technique. Higher temperatures led to higher yields (41–60%) and better quality of the resultant CB. Above 1150 °C, the CB samples were comparable with commercial CB products, with low ash (<0.1%), low volatile matter (<6.1%), moderate BET surface area (11–24.2 m2g−1), and high C contents (~94–99%). Quality was also improved as Rtime or O2 increased but at some sacrifice to the total yield. HRF-CB aggregates were morphologically complex, highly structured and had good thermal stability, which increased with increasing process temperature, Rtime and O2 concentration, respectively. Interestingly, the hydroxyl, carbonyl and carboxyl surface groups in the HRF-CB were higher (54 – 69%) than commercial products (0–59%) under all process conditions, which is a desirable trait for enhanced bonding and mechanical properties but typically introduced to commercial CB by secondary procedures. Given their comparable properties, CB from heavy residues of spent tyre pyrolysis oil may be a suitable replacement for commercial CBs used in rubber reinforcement.

Characteristics and combustion kinetics of fuel pellets composed of waste of polyethylene terephthalate and biomass

BACKGROUND AND OBJECTIVES: The needs of fuel pellets from varied feed stocks have opened up opportunities and challenges for pellets production from non-woody biomass. Wastes of plastic recycling and wood sawing contained a high potential for energy source and suited for pelletizing as a solid fuel. METHODS: The characteristics and combustion kinetics of fuel pellets made using a mixture of waste of polyethylene terephthalate and biomass (Tectona grandis Linn.f) with a polyethylene terephthalate to biomass ratio of 9:1. The investigation covered physico-chemical properties and their functional group analysis, heavy metal concentration and ionic leachability testing, and ash analysis. In this context, thermogravimetric analysis was used in an atmosphere of oxygen gas, over a temperature range of 50-800 °C and at different heating rates. The work ends with discussion of the kinetics study via three comparative evaluations and the feasibility of fuel pellets for energy utilization. FINDINGS: Pelletizing with this ratio (9:1) was present the durability of PET/biomass pellets, a uniform dimension, ease handling, storage, and transportation common as woody pellets. Some technical challenges such as low moisture content and high volatile matter content were feedstock dependent. The major characteristics were a combination of those from both the constituent materials. Functional groups of the pellets were contributed by terephthalate and lignocellulose. The addition of a small amount of biomass in pellets could improve their thermal decomposition behavior. The properties of the polyethylene terephthalate/biomass pellets indicated that were fit for combustion with a high heating value equal to 19.20 MJ/kg. Heavy metals and ionic contaminants were below the maximum limits of the standards because of the cleanliness of the raw materials. However, the minor effects of earth materials and a caustic soda detergent were resulted in the alteration of residue chemicals. The pellets had lower ignition, devolatilization, and burnout temperatures than the original polyethylene terephthalate waste; likewise, the peak and burnout temperatures shifted to a lower zone. The activation energy values obtained using the Kissinger-Akahira-Sunose, Ozawa-Flynn-Wall, and Starink models were similar and in the range 142–146 kJ/mol. CONCLUSION: These findings may provide crucial information on fuel pellets from blended polyethylene terephthalate/biomass to assist the design and operation of a co-combustion system with traditional solid fuels. Such modifications of fuel pellets suggest the possibility of operating in large-scale furnace applications and can further be upgraded to other fuels production via modern bioenergy conversion processes.

Petrography, Mineralogy, and Geochemistry of Thermally Altered Coal in the Tashan Coal Mine, Datong Coalfield, China

A suite of coal samples near a diabase dike were collected to investigate the petrographic, mineralogical, and geochemical characteristics of thermally altered coal in Datong Coalfield, China. Proximate analysis, vitrinite reflectance measurement, and petrographic analysis were applied to identify and characterize the alteration halo; optical microscope observation, qualitative X-ray diffractometry, and SEM-EDS were applied to study the phases, occurrence, and composition of minerals; XRF, ICP-MS, and AFS were applied to determine concentrations of major and trace elements; and the occurrence modes of elements were studied by correlation and hierarchical cluster analysis as well as SEM-EDS. The results demonstrated that the 3.6 m dike has caused an alteration halo of approximately 2 m in diameter. In addition, the thermally altered coals were characterized by high vitrinite reflectance, low volatile matter, and the occurrence of thermally altered organic particles. Dolomite and ankerite in the thermally altered coal may be derived from hydrothermal fluids, while muscovite and tobelite may be transformed from a kaolinite precursor. The average concentration of Sr in the Tashan thermally altered coal reached 1714 μg/g, which is over 12 times that of the Chinese coal; the phosphate minerals and Sr-bearing kaolinite account for this significant enrichment. The cluster analysis classified elements with geochemical associations into four groups: group 1 and 2 were associated with aluminosilicates, clays, and carbonates and exhibited enrichment in the coal/rock contact zone, indicating that the dike may be the source of the elements; group 3 included P2O5, Sr, Ba, and Be, which fluctuate in coals, suggesting that their concentrations were influenced by multiple-factors; group 4 did not manifest obvious variations in coals, implying that the coal itself was the source.

Experimental and theoretical study on the inhibition effect of CO2/N2 blends on the ignition behavior of carbonaceous dust clouds

Gaseous inhibitors are used in many industries for the explosion prevention of combustible dusts, mitigating the potential hazard to humans, properties and environments. This work experimentally and theoretically studied the inerting effect of gaseous inhibitors on the ignition process of dust clouds in O2/N2/CO2 atmospheres, with an emphasis on the role of the CO2/N2 ratio. 10 different combustible carbonaceous dusts were selected, including grain dust, biomass dust and coal dust. Experimental results showed that the inhibition effect of CO2/N2 is closely related to the ignition mechanism of dust clouds. Specifically, a higher ratio of CO2/N2 yields a stronger inhibition effect on the ignition process of dust samples with relatively low volatile matter contents predominated by heterogeneous ignition. In addition, two novel steady-state ignition mechanism models were developed to interpret the experimental observations. Maxwell-Stefan equations were used to describe the diffusivity in the ternary O2/N2/CO2 gas mixtures. The analytical results were in good agreement with the experimental data of the minimum ignition temperature of dust cloud (MITC) in oxygen-lean atmospheres. The mechanism modelling can be used to estimate the critical ignition temperature of all carbonaceous dust clouds with a wide range of volatile matter content under different inert atmospheres, which will provide a reference for the explosion hazard assessment of dust posed by a hot surface in the process industries.

Hydrothermal carbonization of sugarcane industry by-products and process water reuse: structural, morphological, and fuel properties of hydrochars

Hydrothermal carbonization (HTC) has emerged as a promising technology for sustainable use and waste valorization. One major challenge of HTC technology is the process water (PW) disposal or reuse, which is rich in dissolved organic carbon. This study evaluated the (i) potential of HTC to transform sugarcane industry by-products (sugarcane bagasse and vinasse) into useful materials for energy purposes, after, (ii) carry out the PW reuse in a novel HTC process with sugarcane bagasse. Relationships among composition, structure and morphology with fuel properties of hydrochars were evaluated. All hydrochars had lower volatile matter and higher fixed carbon content compared to the raw biomass. In addition, the decrease of H/C and O/C atomic ratios indicated an enhancement of the dehydration and deoxygenation reactions. Furthermore, the higher heating values (HHV) of hydrochars were in the range of 21.10–23.78 MJ kg-1, compared to 15.43 MJ kg-1 of the sugarcane bagasse. This result added to those from the van Krevelen diagram showed that the hydrochars presented fuel properties similar to conventional non-renewable energy sources, such as bituminous coal. Overall, the PW reuse did not promote great differences in the hydrochar properties and, consequently, no big changes on their fuel properties. Further, the hydrochar produced with sugarcane bagasse, vinasse, and sulfuric acid showed the highest heating value, and it was the most hydrophobic hydrochar among the others investigated. Therefore, the present study showed HTC and PW reuse as promising methods to treat the sugarcane industry by-products for solid fuel production.

Performance of Some Biocoal Briquettes Produced from Mixture of Sawdust and varying Nigeria Coals as Composite Domestic Fuel

Performance evaluation of biocoal briquettes from three different coal mines in Nigeria mixed with sawdust as composite domestic fuel was carried out. Samples of coals collected from Owukpa, Okpara, and Onyeama mines were pulverized and blended with sawdust at various constituent ratios of coal/sawdust of 0.0/100, 10/90, 20/80, 30/70, 40/60, 50/50 and 100/0.0. Cassava starch was used as binding material while calcium hydroxide was used for desulphurization. Tests carried out included proximate analyses, ultimate analyses, and performance analyses. Results showed that fixed carbon in all the coal samples ranges from the highest fixed carbon of 63.81% for Okpara (OK) to the lowest of 62.87% for Owukpa (OP70/30) while sawdust was 21.03%. The Onyeama Coal has 1.25% ash content compares with 5% for Owukpa. Onyeama coal contains the highest volatile matters of 29.61% while Owukpa biocoal briquette (OP50/50) has the highest percentage heat utilization of 88.61 and lowest specific fuel consumption of 0.31kg/kg. Onyeama coal (ON90/10) has the highest calorific value of 33.25 MJ/kg. The addition of sawdust in the biocoal briquettes resulted in lower volatile matter, low hydrogen, high percentage heat utilized and low specific fuel consumption.Keywords- Biocoal briquette, sawdust, proximate analysis, ultimate analysis, fixed carbon

Effects of volatile matter and oxygen concentration on combustion characteristics of coal in an oxygen-enriched fluidized bed

Oxygen-enriched combustion in fluidized bed is a promising clean coal combustion technology which can efficiently control the emission of coal-fired pollutants, especially CO2. In this paper, by using several judging methods, the combustion characteristics of five kinds of coal under four different oxygen concentrations (20.9%, 27.8%, 40.7% and 52.7%, CO2 as equilibrium gas) were measured in the small-scale fluidized bed reactor with electric heating in detail. The oxygen consumption and volatile release characteristics were explored online. The influence of coal types, volatile matter and oxygen concentration on coal combustion characteristics was analysed. It’s found that the higher the bed temperature was, the faster the reaction rate was and the more oxygen consumption was. At a certain oxygen concentration and proper bed temperature, the separated combustion of volatile and char were observed. When the oxygen concentration was high, the separation phenomenon was more obvious. High-volatile, a certain bed temperature and oxygen concentration were the basic factors for the formation of separated combustion. The total volatile matter is not comprehensive as the index of reaction combustion characteristics and the effect of combustible components should be specifically considered. It’s found that for the coal with high combustible components, the separated combustion is more obvious. Volatile matter plays a dual role in the ignition and combustion of coal. The volatile matter (lower volatile matter) of some coals has a great promoting effect on coal combustion at higher temperature, while that (higher volatile matter) of other coals is not, which is closely related to the properties of char and the diffusion of volatile matter in pores.

Analysis of the Limited Electrochemical Capabilities of Exhausted Olive Pomace Biochar as Fuel in Direct Carbon Fuel Cell

Exhausted olive pomace (EOP) biochar prepared by carbonization at 400 °C is investigated as fuel in direct carbon fuel cell (DCFC) with an electrolyte supported configuration. Feasibility of using EOP biochar in DCFC is confirmed showing a maximum power density of 10 mW.cm-2 at 700 °C. This limited DCFC performance is compared with other biochars prepared under similar conditions and interrelated to variable biochar physico-chemical characteristics and their impact on DCFC chemical and electrochemical reaction mechanisms. High ash content (21.55%) and low volatile matter (40.62%) of EOP biochar are among the main causes of DCFC limited output. Silica is the major impurity in EOP biochar ash explaining the limited cell performance as it causes low reactivity and limited electrical conductivity because of its non-crystal structure. The relatively poor DCFC performance when fueled by EOP biochar can be overcome by further pre- and post-treatment of this renewable fuel.

Preparation and characterization of activated carbon from wheat straw to remove2, 4-dichlorophenoxy acetic acid from aqueous solutions

This study was focused to investigate the adsorptive behavior of activated carbon prepared from wheat straw treated with acid and base for the removal of 2, 4-dichlorophenoxy acetic acid (2,4-D). The morphology of the adsorbent was characterized using infrared spectroscopy and scanning electron microscopy. Compared with acid activated wheat straw, base activated wheat straw has provided lower ash content, moisture and volatile matter. However, it has higher iodine number than acid activated wheat straw. The removal of 2,4-D from aqueous solution was investigated at various physicochemical parameters such as pH (2–10), contact time (5–60 min), temperature (20-80 oC), amount of adsorbent (0.1-1.4 g) and initial concentration of 2,4-D (1.0-25 mg/L). The removal efficiency of 2,4-D in aqueous solution was found to be 92.02%. The equilibrium data were analyzed using Langmuir and Freundlich isotherm and the Langmuir model better describes that the active adsorption sites were homogeneously distributed on the surface of the adsorbent. Therefore, the activated carbon prepared from wheat straw treated with base can be used as efficient and cost-effective method to remove 2,4-D from aqueous solution.

Investigation of eggshell as catalyst on the torrefaction of empty fruit bunch

Biomass derived energy is considered as a sustainable energy. However, the utilization of biomass as a solid fuel has many challenges such as low energy density, high moisture and volatile matter content. Hence, torrefaction is one of the thermal treatments applied to enhance the fuel properties of biomass. The objective of this research was to investigate the influence of calcium-based catalyst on the torrefaction of empty fruit bunch (EFB). Waste eggshell was utilized as Ca source as it stands to be beneficial in terms of availability and cost. The effect of torrefaction parameters such as temperatures from 200 °C to 300 °C, residence times from 30 min to 90 min, and the catalyst amounts from 0 wt% to 15 wt% were investigated. Among the three process parameters, temperature had the most significant effect on mass and energy yield. However, the effect of residence time and the catalyst loading was relatively insignificant. With the increment in torrefaction temperature, higher heating value (HHV) and carbon content in torrefied biomass increased. After catalytic torrefaction, the torrefied biomass displayed increment on cellulose crystallinity and volatile matter content. Moreover, the surface structure of catalytic torrefied biomass at 300 °C was turned into highly fibrous surface due to degradation of lignin. The results from this study concluded that the eggshell catalyst did not alter the characteristics of solid fuel significantly in torrefaction.

Physiochemical Characterization and Potential of Synthesis Gas Production from Rubber Wood Biomass by Using Downdraft Gasifier

Bioenergy has gained great interest in the recent years for being environmentally friendly and renewable energy resource. Southern Thailand is well-known for agro-industry including rubber tree plantations and processing, which provide biomass that could be applied to produce bioenergy. Thus, this study aimed to investigate the energy potential of Rubber Wood Chips (RWC), Rubber Wood Pellets (RWP), Unburned Char (UBC) from rubber wood, blended RWC:UBC (50:50%) and blended RWP:UBC (50:50%). The physiochemical properties including bulk density, proximate composition, ultimate composition, heating value, Thermogravimetric Analysis (TGA), and lignocellulose content were determined for the biomass samples. The thermochemical conversion of biomass to syngas was performed using a downdraft gasifier operated at equivalence ratio 0.3. The results showed that the biomass was rich in carbon (content ranging from 44.77 to 58.54%) making it suitable for use as a solid fuel for gasification or combustion. The moisture contents of the biomass samples were below 10%. The contents of volatile matter in RWC and RWP were 74.40 and 75.40%, respectively. The UBC had a high fixed carbon content (50.60%) and comparatively low volatile matter (19%). The bulk densities of RWC, RWP and UBC were 193, 555 and 177 (kg/m3), respectively. The TGA showed the maximum weight loss of RWC and RWP around 400 °C, but this was at 800 °C for UBC. The higher heating values of RWC, RWP and UBC were 17.8 MJ/kg, 17.4 MJ/kg and 19.3 MJ/kg, respectively. The RWC and RWP had high cellulose and hemicellulose contents while UBC was rich in lignin. The syngas obtained from any of these biomass samples was mainly CO (10.81-22.67%) and CH4 (0.06-3.16%) with the lower heating value ranging from 2.78 to 4.72 MJ/Nm3. These results indicate that rubber wood biomass in various forms has relatively high potential for bioenergy applications via gasification, and it can help to support the renewable energy sector in Thailand.

CHEMICAL ANALYSIS OF COAL DEPOSIT FOR POWER GENERATION: A CASE STUDY OF BUKAN-KWATO IN LAFIA L.G.A OF NASARAWA STATE, NIGERIA.

Nigeria, the most populated country of Africa is reactivating her coal industry as supplementary energy source. Bukan - Kwato coal field is one of the recently discovered coal deposits in Lafia that is receiving great attention from investors and entrepreneurs of coal energy. The coal serves as prime target for power generation by the Nigerian Government, yet little is known about the basic properties of the deposit. The research seeks to achieve the objectives of collection of fresh coal samples from the mining site, so as to carry out the chemical analysis, determine the calorific value and to suggests best methods for processing of the coal. The coal samples were collected from the study area and were subjected to proximate, ultimate and calorific value determination in order to determine the intrinsic properties of the coal. Proximate analysis were carried out on pulverized samples using the Muffle furnace, carbon and hydrogen were determined using the method described in the Liebig method while nitrogen was obtained using the Kjeldahl method. Sulfur content were obtained using the ESCHKA method, oxygen content were calculated by difference on an air dried basis. Calorific value were determined using the Isoperibol calorimeter. The results obtained compared with the standard pulverized coal fire plants shows that the coal has a medium to high carbon content of 54.68%, high moisture content of (9.72%), Nitrogen (3.5%), Sulfur (24.24%) and Ash (31.74%) with a corresponding low volatile matter of 20.28%. The high ash content in the coal can be used as thermal coal for power generation.

Thermogravimetric analysis of hazardous waste: Pet-coke, by kinetic models and Artificial neural network modeling

Pet coke is a hazardous waste obtained from petroleum refinery on an enormous scale. Understanding pet coke’s material characteristics and its decomposition kinetics is a prerequisite for its highly stable combustion behavior. Proximate analysis revealed that high fixed carbon and low volatile matter makes pet coke a low reactive fuel. Advanced analytical techniques like FTIR, XRD, ICP-OES revealed that pet coke is predominantly inorganic, constituting graphitic carbon and hydrogenation materials like nickel & vanadium, respectively. Thermogravimetric studies were conducted, and average activation energy calculated by model-free methods was in the range of 152.70 to 206.18 kJ/mol, respectively. The study of solid state reaction mechanism by Coats-Redfern, Kennedy-Clark and Master plot methods suggested contracting volume (g(α) = (1-(1-α))1/3) and two dimensional diffusion reaction mechanism (g(α) = (1-α) ln(1-α) + α) models which falls under decelerating type reaction mechanism. Combustion indices of pet coke like CCI, DI, DB were evaluated at different rates of heating. Pet coke’s thermal degradation behavior were modelled using an artificial neural network (NN7). The research carried out permits to identify the characteristics of one of the most dominant hazardous waste, along with the futuristic potential usage and the findings provide reliable kinetic parameters for scale up, utilization, optimization, limitation for the system.

Combustion Behavior of Fuel Briquettes Made from Ulin Wood and Gelam Wood Residues

Solid fuel from the briquetting of ulin wood and gelam wood residue was investigated in this work. The effect of compaction pressure (10, 12, and 15 MPa), and briquette formulation were investigated. The ulin wood and gelam wood were blended in the mixing ratios of 100:0, 70:30, 50:50, 30:70, and 0:100, respectively. The size of the particle was fixed of 50 µm. The ulin wood and gelam wood were carbonized under fixed temperature (500oC), and time (120 min). The gelatinized binder (cassava starch) was 20% of the total briquettes weight. The densification was carried out using the briquetting machine (piston-press type) laboratory scale. The compaction pressure briquette had a significant effect on some characteristics of briquette (ash content, moisture content, volatile matter, bulk density, and combustion rate). An increasing in compaction pressure briquettes resulted in low ash content, moisture content, and volatile matter but the reverse is the case for bulk density. However, the mixing ratio slightly affected. High combustion rate (3.18 g/min) achieved at low compaction pressure (10 MPa).

Characterization of charcoal produced by different Pyrolyzing techniques

Different pyrolyzing techniques are assumed to yield products with different content and adsorption rate. This study aimed to characterize five coconut charcoal samples from different pyrolyzing techniques such as Drum Kiln, Pit Method, Top Lift Updraft Method for TLUD – Top Sample &amp; TLUD – Bottom Sample, and Hookway Retort to determine the best production method that will yield a quality of charcoal suitable for adsorption applications. Proximate analysis and adsorption kinetic studies were done to characterize and determine the rate of adsorption. Charcoal samples were ranked based on the following criteria and weights: 70% for adsorption capacity, 20% for fixed carbon, and 10% for the volatile matter. High adsorption capacity, high fixed carbon, and low volatile matter are good charcoal qualities for adsorption. For proximate analysis, ASTM Methods (ASTM D3302, ASTM D3175-17, ASTM D3174-12, ASTM D3172-13) were used. Experimental data showed that fixed carbon content of charcoal samples from Drum Kiln, Pit Method, TLUD-Top, TLUD-Bottom, and Hookway was 54.63%, 56.84%, 64.77%, 45.85%, and 56.59% respectively; while 30.69%, 31.65%, 20.65%, 43.39%, and 24.13% respectively for the volatile matter. For adsorption kinetic studies, optimization was done using Box-Behnken design with initial concentration, adsorbent dose, and pH as factors. The Hookway sample was subjected to optimization, where its optimum conditions were used for the rest of the charcoal samples. The experimental data for the adsorption kinetic studies showed that the pseudo-second-order exhibited the best fit for all the charcoal samples. The coefficient of determination for charcoal samples from Drum Kiln, Pit Method, TLUD-Top, TLUD-Bottom, and Hookway Method are 0.9253, 0.944, 0.7267, 0.9885, and 0.9216. Applying the weights, the best charcoal sample is from Kiln, followed by Pit, TLUD-Bottom, TLUD-Top, and Hookway. Production temperature, pressure, and humidity could be employed in future studies to determine what affects the quality of charcoal during pyrolysis.

Production of Biocrude and Charcoal from Fast Oxidative Pyrolysis of Cassava Pulp Residue Using a Fluidized Bed Reactor

Cassava pulp (Manihot esculenta Crantz) residue (CPR) is the solid waste generated from the cassava processing industry. In the bench-scale experiments, fast oxidative pyrolysis of CPR was carried out in a fluidized bed reactor, using uncondensed recycled pyrolysis gas as carrier medium to produce charcoal and biocrude. The influence of three gas recycle rates, ranging from 0.60 to 2.3 Sm3 h –1 , on the product yields and characteristics was investigated. Results suggest that an increase in the recycle rate will lead to an increase in biocrude yield and a decrease in the charcoal yield. The product yields of biocrude and charcoal were 15.68 ± 2.08 percent and 24.29 ± 3.31 percent, respectively. The biocrude product was mainly composed of alcohols, phenols, aldehydes, ketones, alkanes, and alkynes. The charcoal obtained has a heating value that is around 85 percent higher than that of the CPR feedstock. It has a high fixed carbon content of around 67 percent, but a low volatile matter content of only around 28 percent. At the pyrolysis temperature of around 500 °C, the uncondensed pyrolysis gas compounds consisted primarily of N2 and C2 H6 , with small amounts of H2 , and higher hydrocarbon compounds. Results suggest the potential for generating biofuel products from the fast oxidative pyrolysis of CPR.