Char Briquettes Research Articles

Assessment of Physical and Combustion Properties of Fecal Sludge‐Derived Char Briquettes Bonded by Waste Papers, Cassava, and Banana Peels

ABSTRACTInnovative approaches using biomass and waste for briquette production are needed to address energy deficiencies in household cooking and heating. Fecal sludge (FS) can serve as a feedstock for briquette production. However, the physical and chemical qualities of the briquettes produced using FS and different binding materials are still inadequate. This article examines the physical and combustion properties of carbonized FS bio‐briquettes made using five different binders, namely, waste paper (WP), cooked banana peels (CB), non‐cooked banana peels (NB), cooked cassava peels (CC), and non‐cooked cassava peels (NC). Bio‐briquettes were made at various binder ratios (0%, 25%, 50%, and 75%) using a locally fabricated manual pressing machine. Overall, the study discovered that all bio‐briquettes fabricated can be utilized for heating and cooking; however, the type and quantity of binders employed influence their quality. The study concluded that FS bio‐briquettes blended with 75% WP binder were the best, outperforming others in many tests including drying rates (6 days), physical tests (passed shattering [95%], water boiling [240 s], and tumbling tests [100%]), and burning/thermal efficiency (19.23 MJ/kg). The study suggests further research to be conducted on combining FS with other biomass feedstocks to decrease volatile matter and emissions in bio‐briquettes made with FS and non‐carbonized binders.

Potential use of faecal sludge derived char briquettes as an alternative cooking energy source in Dar es Salaam, Tanzania: “Nexus between Sanitation and Energy (SDG 6 & 7)”

Coprophobia characterizes faecal sludge (FS) as an unpleasing raw or partially digested faecal waste with no recycling value. However, this so-called waste is claimed to have tremendous recycling values after being pyrolyzed. This study hypothesized that char briquettes made from FS might have the potential of replacing charcoal consumption in Dar es Salaam, Tanzania. Quantitative methods were used to examine the proximate, emissions and environmental benefits of faecal sludge char briquettes in comparison to wood charcoal from Dalbergia melanoxylon (locally known as Mpingo). Results revealed that FS collected during the dry season exhibited a higher total solids content (26%) compared to that collected during the rainy season (20%). This difference was statistically significant (p = 6.12405E-14 at α=0.05). Dewatering and further drying the FS to a minimum of 90% total solids yielded an energy value of 11-12 MJ/kg, which was lower than that of uncarbonized wood (firewood) at 19 MJ/kg. Production of FS char briquettes bonded by paper waste has a lower energy value (13 MJ/kg) than that bonded by cassava starch (14.6 MJ/kg). The average energy value of FS char briquettes is almost half that of wood charcoal (26 MJ/kg), meaning that the replacement of 1 kg of charcoal consumption would require 2 kg of FS char briquettes is required. Nevertheless, due to an ineffective collection of FS to be used in the production of char briquettes, only 8% of charcoal consumption in the city can be replaced. It is recommended to use the produced briquettes in open kitchens with ample oxygen circulation, as they emit carbon monoxide levels exceeding the allowable limits set by the Tanzania Bureau of Standards.

Combustion characteristics of briquettes made from microwave-assisted co-pyrolysis products of palm shell and LDPE

Briquettes are solids that are generally made from agricultural waste materials. Char briquettes are one of the alternative energies for daily needs. This study used char from palm shell and LDPE microwave-assisted co-pyrolysis at 450 Watts. The briquettes were made from the product of co-pyrolysis of palm shell and Low-Density Polyethylene (LDPE) with variations in the composition of 0:100, 50:50, and 100:0 and pressure of 50 kg/cm2, 100 kg/cm2, 150 kg/cm2, and 200 kg/cm2. In this research, thermogravimetry analysis (TGA) was the method used to determine combustion characteristics. This study aimed to determine the combustion characteristics, including the Initiation Temperature of Fixed Carbon (ITFC), Initiation Temperature of Volatile Matter (ITVM), Peak of weight loss rate Temperature (PT), Activation Energy (Ea), and Mass Loss Rate (MLR). The results showed that the increased briquettes pressure increases the ITVM, ITFC, PT, and EA. The higher LDPE composition in the briquettes decreased the ITVM, ITFC, PT, and Ea, but increased the MLR.

Heating and emission characteristics from combustion of charcoal and co-combustion of charcoal with faecal char-sawdust char briquettes in a ceramic cook stove

Over reliance on charcoal has accelerated deforestation in sub-Saharan Africa. Seeking alternative sustainable and environmentally friendly sources of biomass energy to meet the escalating energy demand is therefore vital. However, limited evidence exists on the concentrations of toxic emissions of different biomass fuels. Herein, dried human faeces and sawdust were pyrolyzed at 350 °C to produce biochar and mixed in equal ratio to produce briquettes through densification, with molasses (10 wt.%) used as a binder. A comparative study on the heating properties and emission level of carbon monoxide (CO), nitric oxide (NO), and hydrogen sulphide (H2S) during combustion of charcoal, and co-combustion (50:50 wt. %) of charcoal with briquettes was conducted. The thermal profile of the flue gases indicated rapid combustion of volatile gases followed by slow oxidation of the char. Co-combustion significantly (P < 0.05) enhanced the amount of heat energy released with flue gases temperatures reaching a peak of 475 °C. The briquettes had a gross calorific value of 19.8 MJ/kg which was lower than 25.7 MJ/kg for charcoal. Combustion of charcoal did not emit NO, however the concentration of CO was above the critical short term limits of 35 ppm. The concentration of CO and H2S was above the short term exposure limits of 35 ppm, and 0.005 ppm, respectively, during co-combustion, whereas NO concentration was below dangerous exposure levels of 100 ppm. These results suggest that co-combustion of charcoal with the briquettes is a promising approach to generate safe and sufficient heat energy for cooking and reduce deforestation.

Potential Economic and Environmental Benefits of Faecal Sludge Derived Compost and Char Briquettes: The case of Dar es Salaam, Tanzania

The concept of resource recovery, particularly from waste has recently gained much attention and popularity. The aim of this study was to quantify the potential economic and environmental benefits of recovering nutrients and energy from faecal sludge (FS). The empirical data were collected from three unplanned settlements of Dar es Salaam City at Keko, Kipawa and Manzese. Two scenarios were developed to recover nutrients and energy. The estimations of potential amounts of compost and char briquettes were performed by using the resource value mapping (REVAMP) tool. Results from REVAMP indicated daily economic benefits across the study areas ranging between 680 and 950 USD for energy and up to 7,000 USD for nutrients recovered, based on the faecal sludge composition. In general, FS derived compost was found more profitable than FS derived briquettes. The analyzed environmental benefits include saving the estimated to 5 hectares of forest area from being cut when substituting the use of wood charcoal with FS-derived briquettes. Since the composting process resulted to be more profitable option between the two, this study recommends the adoption and scaling up. However, guidelines and standards should be developed for proper practices.&#x0D; Keywords: Faecal sludge; resource recovery; resource value mapping; briquettes; compost; economic benefits; environmental benefits

Preparation of binder-less activated char briquettes from pyrolysis of sewage sludge for liquid-phase adsorption of methylene blue

Binder-less activated char briquettes from sewage sludge were prepared and used for the liquid-phase adsorption of methylene blue. The properties of sludge char briquettes prepared under the different initial sludge moisture content, compression pressure, and heating rate were systematically investigated through the tests of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), surface and mechanical properties, burn-off rates, methylene blue adsorption kinetics and isotherms. All of the prepared briquettes presented hierarchical structures and microporous/mesoporous characteristics, and the increase of initial sludge moisture content from 10 to 30 wt% resulted in a great increase of surface area (SBET), total pore volume (VT), apparent density, and a slight decrease of mechanical performance. The decrease of compression pressure markedly enhanced the equilibrium adsorption capacity (qe, exp), owing to the decreased diffusion resistance and blockage of diffusion pathways inside briquettes. In consideration of the mechanical performance and adsorption capacity, the optimum preparation condition was obtained at the initial moisture content of 30 wt%, compression pressure of 25 MPa, and heating rate of 10 °C/min, in which the axial compressive strength (ACS) and qe, exp of the prepared briquettes were as high as 22.2 ± 3.1 kg/m2 and 316.9 mg/g. The results also showed that the equilibrium adsorption data fit well into the pseudo-first order model system, and the adsorption isotherms followed the Langmuir isotherm model, suggesting that the adsorption process was attributed to physical adsorption, and was inclined to happen on the adsorption sites with the same energy level. Finally, the thermal regeneration tests demonstrated that the binder-less briquette had a good regeneration performance and was worthy of reusing for industrial applications.

Development and Characterization of Polypropylene Waste from Personal Protective Equipment (PPE)-Derived Char-Filled Sugar Palm Starch Biocomposite Briquettes.

Slow pyrolysis using a batch reactor at 450 °C was applied to the polypropylene (PP) powder derived from Coronavirus Disease 2019 (COVID-19) isolation gown waste to yield char briquettes, using sugar palm starch (SPS) and a manual hydraulic press. These studies are significant because of reductions in plastic waste from the preparation of barbecue coal due to environmental sustainability. The results presented here include the physical, morphological, thermal, combustion, and mechanical properties of char when reinforced with various percentages of SPS loadings (0, 10, 20, 30, and 40%), which act as a matrix/binder to produce char/sugar palm starch (C/SPS) composites. The physical and morphological characteristics of C/SPS composites were determined using Fourier transform infrared (FTIR) and field emission scanning electron microscopy (FESEM). On the other hand, the thermal and combustion properties of the C/SPS briquettes were studied via thermogravimetric and bomb calorimeter analysis. The results show that the compressive strength of the briquettes increased as the SPS loading increased, whereas the higher heating values (HHV) reduced. The findings indicate that C-80/SPS-20 briquettes presented excellent combustion characteristics (1,761,430 J/g) with satisfactory mechanical strength (1.463 MPa) in the compression test. Thus, C-80/SPS-20 briquettes are the most suitable composites for domestic and commercial uses.

Structural and functional relationships of activated char briquettes from pyrolysis of sewage sludge for methylene blue removal

Activated char briquettes from pyrolysis residue of sewage sludge were prepared and characterized for methylene blue removal. The briquettes were prepared with different binder (phenolic resin) content (15–25 wt%), compression pressure (2.5–7.5 MPa) and thickness (3.5–14 mm), followed by CO2 or H2O activation under different temperatures. The effects of these parameters on the compositions, surface properties, apparent densities, mechanical properties, methylene blue adsorption kinetics and isotherms were systematically investigated. The results indicated that all of the prepared briquettes showed a characteristic of hierarchical porous structures, as well as high mechanical performance with impact resistant index much higher than 50. The increase of binder content from 15 to 25 wt% can result in marked increase of surface area (SBET), total pore volume (VT), apparent density and mechanical performance of the briquettes. According to the adsorption kinetics of methylene blue, the highest equilibrium adsorption capacity (qe,exp) for CO2-activated and H2O-activated briquettes were 194.6 and 203.6 mg/g. Both the increase of binder content and activation temperature markedly enhanced qe,exp, due to the increase of SBET and VT. qe,exp was much lowered by increasing the compression pressure or the thickness of briquettes, owing to the increased diffusion resistance and blockage of diffusion pathways inside briquettes. The adsorption kinetics data of the briquettes fit well into a pseudo-first order model system, suggesting physical adsorption of methylene blue onto briquettes surface. The adsorption isotherms of methylene blue indicated that both the CO2-activated and the H2O-activated briquettes followed a Langmuir isotherm model. The leaching tests of briquettes revealed that the leaching concentrations of Cd, Cr, Cu, Pb, Ni and Zn were much lower than the Chinese standard limits.

Valorisation of solid waste as key opportunity for green city development in the growing urban areas of the developing world

Lack of integrated solid waste management practice in fast-growing cities of developing countries is posing a threat to sustainable and green cities development. The fast growing Jimma City in Ethiopia requires up-to-date waste quantification and characterization data for the planning and implementation of sound waste management options such as composting and energy recovery that could create new jobs and promote private sector involvement. Therefore, we quantified, characterized and evaluated energy potential and nutrient value of household solid waste from Jimma City. Total daily waste generated from the city’s households was estimated to be 85.8 tons, with an average per capita generation rate of 0.56 ± 0.17 kg/day. The biodegradable organic waste comprises 76% by weight and had optimum moisture content and carbon to nitrogen ratio for composting. The energy content of combustible household waste was estimated to be 17.5 MJ/kg for gross heating value and 9.54 MJ/kg for the net heating value that surpasses the lower limit for thermal treatment process to be economically viable. Waste-to-energy conversion of combustible waste of cities could reduce annually about 25,303 metric tons of carbon dioxide equivalent greenhouse gas emissions. Char briquettes produced through pyrolysis of solid waste could be a potential substitute for firewood to prevent deforestation and indoor air pollution. In conclusion, composting and pyrolysis are sound waste management options for green cities development in developing countries while minimizing public health risks and cost of treatment and disposal.

Investigation of potassium transformation characteristics and the influence of additives during biochar briquette combustion

Low energy density and ash fusion problem were problems that limit biomass widespread utilization. To avoid these, maize straw (MS) was blended with two additive –NH4H2PO4 (ADP) and Ca(H2PO4)2 (CPM)-respectively, and the production chain of mixing additive-briquetting-pyrolysis was put forward to produce MS char briquettes (MSC, MSC-ADP and MSC-CPM). Ash fusion characteristics of MS char briquettes after combustion was investigated by XRF, XRD, SEM-EDS and simulation. Results show that the softening temperature increased with the enhanced ratio of P2O5/K2O until 0.2, and CaO/K2O until 0.9. The higher amount of CaO and P2O5, the lower amount of K2O, the better ash fusion characteristics. The P2O5 had larger influence on softening temperature. The surfaces of MSC ashes formed at 1000 °C were fusion and smooth in micro observation, while surfaces of MSC-ADP and MSC-CPM ashes were coarse and the particles were much looser. Both SEM-EDS and XRD results illustrated that phosphorus in additives combined with potassium to produce high melting temperature potassium phosphates rather than low melting temperature potassium silicates. The potassium fixation ability of ADP was better than that of CPM. The calcium silicates and calcium phosphates produced by CPM could improve ash characteristics.

Investigation of Maize Straw Char Briquette Ash Fusion Characteristics and the Influence of Phosphorus Additives

The purpose of this paper is to explore the fuel and ash characteristics of maize straw (MS) char briquettes. The biochar briquettes were made from different pyrolysis temperatures and additives. The pyrolysis and combustion processes were performed in a fixed-bed furnace system. Ash fusion temperatures were tested in an ash fusion point analyzer. Pyrolysis product properties under different pretreatments were analyzed by a combination of X-ray powder diffractometry, scanning electron microscopy with energy-dispersive spectrometry, Fourier transform infrared spectroscopy, and X-ray fluorescence. The high fusion tendency of MS char was observed thorough ash fusion indexes. The softening temperature decreased with a deduced base to acid and an elevated pyrolysis temperature. Aromatization became obvious in a high-temperature pyrolysis product. KH2PO4 and Ca(PO3)2 were detected in MS ammonium dihydrogen phosphate and MS calcium phosphate monobasic, accompanied by the decreasing intensity of KCl. Phosphorus g...

Application of char products improves urban soil quality

AbstractUrban soils are a key component of the urban ecosystem but little research has considered their quality and management. The use of char or partially combusted char products as a soil amendment is becoming popular worldwide because of perceived benefits to fertility and the potential for increasing carbon sequestration. In this study, we assessed the effect of applying coarse and fine char material on the quality of four different types of soil‐based root‐zone mixes typically used for turfgrass and general landscaping in Singapore: clay loam soil, approved soil mix (ASM, 3 soil:2 compost:1 sand), 50:50 (sand/soil) and 75:25 (sand/soil). Char briquettes made from sawdust were mixed thoroughly at rates of 25, 50 and 75% by volume with the soil mixes. Results showed that addition of char (both coarse and fine) significantly enhanced the carbon content of the mixes, with the largest increase being associated with the 50% and 75% additions. Soil nutrients (total N, extractable P, K, Ca and Mg) and mean weight diameter of aggregates were also significantly increased following the application of char. The clay loam and the 50:50 and 75:25 soil mixes were more responsive to the addition of char than was ASM.

Low-cost potassium-containing char briquettes for NO x reduction : Bueno-Lopez, A. et al. Energy & Fuels, 2002, 16, (4), 997–1003

Low-cost potassium-containing char briquettes for NO x reduction : Bueno-Lopez, A. et al. Energy & Fuels, 2002, 16, (4), 997–1003

Low-Cost Potassium-Containing Char Briquettes for NOx Reduction

The activity of potassium-containing char briquettes, for NOx reduction, has been investigated at 350 °C, using a mixture of 0.2%NO/5%O2/N2. The samples have been prepared from a Spanish bituminous coal and a coal tar−formaldehyde resin (resole) as binder. The influence of a number of variables relating to the preparation process, such potassium loading and pyrolysis temperature, on their reduction capacity has been analyzed. For comparative purposes, a set of binder-free samples with different potassium contents has been prepared. Potassium contents highly affect the selectivity of the briquettes. Samples prepared with high potassium loading exhibit satisfactory selectivity values with very low burnoff. Lifetime tests, until complete consumption of the sample, have been performed with the samples exhibiting high selectivity values. The most important finding is that high selectivity values are maintained during the whole life of the briquette. The binder affects the reaction kinetic and the lifetime of t...

00/00662 Effect of binder addition on the mechanical and physicochemical properties of low rank coal char briquettes

00/00662 Effect of binder addition on the mechanical and physicochemical properties of low rank coal char briquettes

Effect of binder addition on the mechanical and physicochemical properties of low rank coal char briquettes

A series of chars obtained from a low rank coal by N2 pyrolysis at different temperatures was blended in different proportions with a commercial binder pitch and pressed at 125 MPa in a mould-and-plunger press. The briquettes obtained (1.5 cm long, 1 cm diameter) were subjected to a heat treatment consisting of a curing stage at 200°C in air followed by a carbonization stage in N2, at 500°C or 700°C depending on the starting char. A further stage of activation in steam was performed on the briquettes as well as on the chars. The mechanical properties of the briquettes were assessed by means of their impact resistance index and compressive strength, and their surface properties were determined by N2 B.E.T. surface area and pore volume measurements, as well as by acidic–basic titration. An increase in pitch content within the range tested (10–25% by weight) improves significantly the impact and compressive resistance of the briquettes. Whatever the amount of pitch used, the mechanical resistance of the briquettes decreases after activation. In both cases (before and after activation) the mechanical resistance of the briquettes depends on the starting char and the pitch content used. The changes, with respect to parent chars, found in surface properties of the briquettes were explained in relation to textural and acidic–basic properties of the pitch added, as well as to the changes undergone by the char itself during heat treatment. The effect of steam activation on these properties of the briquettes depends on the parent char, pitch content and the temperature of activation.