Feasibility study of co-mixing biomass with additive waste materials for biochar high calorific value of co-firing applications

Energy conversion assessment of vacuum, slow and fast pyrolysis processes for low and high ash paper waste sludge

Towards transparent valorization of food surplus, waste and loss: Clarifying definitions, food waste hierarchy, and role in the circular economy

In this study, the quality of wood fuel pellets, commercially available in the Greek market, was evaluated using the ISO 17225 Standard Requirement Thresholds as a benchmark. The examined quality criteria were calorific value, ash content, mechanical durability, bulk density and moisture content. The reliability of the information on packages was evaluated. Meanwhile, the potential correlation between the most crucial qualitative properties of pellets was investigated to elucidate their potential contribution to pellets’ quality estimation. Most of the pellet brands showed low moisture and ash content and acceptable calorific values for residential use—although the quality of half of the pellet brands was found to be lower than that reported, mainly with regard to the mechanical durability and bulk density. The application of two different collection periods highlighted a stability in quality over time. Higher calorific value seemed to be provided by pellets which had low ash and low moisture content and were mechanically durable. As regards the specific samples, a dark colour and high roughness were correlated with lower fuel quality (impact of 56.2% and 43.6%, respectively).

The influence of manure feedstock, slow pyrolysis, and hydrothermal temperature on manure thermochemical and combustion properties

This study explores the pyrolysis of disposable face masks to produce chemicals suitable for use as fuel, addressing the environmental concern posed by single-use face masks. Co-pyrolysis of biomass with face mask plastic waste offers a promising solution. The research focuses on the co-pyrolysis of biomass and face masks, aiming to characterise the properties for analysis and optimisation. Selected agricultural biomass and face mask plastic waste were subjected to temperatures from 250 °C to 400 °C for co-pyrolysis. Slow pyrolysis was chosen because face masks cannot be converted into useful bioproducts at temperatures exceeding 400 °C. The samples were tested in four different ratios and the study was conducted under inert conditions to ensure analysis accuracy and reliability. The results indicate that face masks exhibit a remarkable calorific value of 9310 kcal/kg. Face masks show a two-fold increase in calorific value compared with biomass alone. Additionally, the low moisture content of face masks (0.10%) reduces the heating value needed to remove moisture, enhancing their combustion efficiency. This study demonstrates the potential of co-pyrolysis with face masks as a means of generating valuable chemicals for fuel production, contributing to environmental sustainability.

This study evaluated the properties of banana pseudo-stem (BPS) biochar derived from two different types of pyrolysis. The fast pyrolysis experiment was performed using a worktable-scale fluidized-bed reactor, while a bench-scale fixed-bed reactor was used in the slow pyrolysis experiment. The preliminary analysis shows that the feedstock contains 80.6 db wt% of volatile matter, 12.5 db wt% of ash and 33.6% of carbon content. Biochar yield reduces as the pyrolysis temperature elevates for both pyrolysis experiments. Fast pyrolysis yields a higher percentage of biochar (40.3%) than biochar yield obtained from the slow pyrolysis experiment (34.9 wt%) at a similar temperature of 500 °C. The evaluation of biochar derived at 500 °C shows that the biochar obtained from the slow pyrolysis process has higher carbon content, heating value, and surface area with lower ash content. Meanwhile, FESEM images show significant differences in surface morphology and the number of pores for biochar derived from fast and slow pyrolysis. These findings indicate the potential and suitability of BPS biochar derived from the slow pyrolysis process in applications such as soil amelioration and solid biofuel.

Coal mining and washing activities in South Africa often lead to the generation of fine and ultra-fine coal which is in most cases discarded due to high handling and transportation costs. Studies conducted revealed that a large quantity of these fines have market acceptable calorific values and lower ash contents. In order to reduce fines discarded, processes have been developed to re-mine and process the fine coal discards with the aim of improving the calorific value, adding them to coarse washed coal to increase the yield as well as pelletizing the fines so as to meet the market specifications in terms of size. The goal of this study was to evaluate the efficiency of fine coal washing using gravity separation methods and comparing the products thereof to the market specifications with regards to the calorific value and the ash content. Coal fines from the No.4 lower seam of the Witbank coalfield in South Africa resulting from a dry coal sorting plant were subjected to a double-stage spiral test work, heavy liquid separation and reflux classifier test work respectively. The reflux classifier achieved products with low ash content and an increased calorific value, at high mass yields. At higher fluidization water flowrate, the reflux classifier performance was superior to that of the spirals with products of lower ash content and higher calorific value. At low cut point densities, heavy liquid separation yielded the cleanest products with very low ash content but at much lower mass yields. As the density increased, the mass yields increased with the ash content while the calorific value decreased. Most of the products from the different processes met most of the local industries’ specifications but none of them met the export market as well as the gold and uranium industry specifications due to the high ash content.

The agricultural waste biomass holds potential as a valuable resource, capable of being converted into high-grade solid fuel for energy production. Despite the ample availability of rice straw and palm oil empty fruit bunch stock, challenges persist with biomass feedstock, such as low calorific values and high slagging-fouling potency. The wet torrefaction process, known as hydrothermal torrefaction, enhances agricultural waste biomass into solid fuel comparable to lignite and sub-bituminous coal. The study investigates the slagging-fouling potential of raw agriculture biomass waste and wet torrefaction-treated variants, evaluating sample characteristics through proximate, ultimate, and calorific value analyses. This study also investigates the potential of the wet torrefaction process as a pre-treatment in multi-process conversion. The moisture content of the wet torrefaction biomass decreased slightly, and the calorific value of the wet torrefaction biomass samples was higher than that of the raw biomass. The result of rice straw wet torrefaction at 240°C was a gross calorific value of 16.29 MJ/kg, equivalent to lignite A, with slagging potential decreased from 0.021 (low) to 0.011 (low), and the fouling potential from 0.921 (medium) to 0.322 (low). The result of palm oil empty fruit bunches, wet torrefaction at 240°C achieved the highest gross calorific value of 20.38 MJ/kg, equivalent to sub-bituminous C coal, with slagging potential reduced from 0.076 (low) to 0.031 (low) and fouling potential reduced from 74.84 (high) to 20.27 (medium). Wet torrefaction shows potential as a pre-treatment for multi-process conversion. Future studies should consider sequential torrefaction (wet and dry methods) that could leverage the advantages of each, reducing slagging and fouling potential while increasing the calorific value.

The increasing depletion of fossil fuel reserves and the need for sustainable energy alternatives have accelerated research on biomass-based briquettes. This study investigates the effect of different catalyst types (6% zeolite, 6% activated carbon, and no catalyst) and binder concentrations (5%, 10%, and 15% w/w) on the physicochemical properties of bio briquettes derived from a mixture of sugarcane bagasse, palm empty fruit bunches (TKKS), and rice husk. Key performance parameters analyzed include moisture content, ash content, and calorific value. The lowest moisture content (2.1%) was obtained using 6% zeolite with 15% binder, while the lowest ash content (5%) was recorded using 6% activated carbon with 5% binder. In terms of energy potential, the highest calorific value (4431.42 cal/g) was achieved with 6% zeolite and 5% binder. However, none of the samples met the SNI 01-6235-2000 calorific value standard (>5000 cal/g), though all met the ESDM minimum threshold (>3500 cal/g), indicating their potential for domestic use. Statistical analysis revealed a quadratic relationship between binder concentration and both moisture and calorific value, highlighting the importance of formulation optimization. The results demonstrate that catalyst type and binder concentration play a critical role in determining the quality of bio briquettes, and a balance between low moisture, minimal ash, and high calorific value must be achieved for practical application. This study supports the development of eco-friendly and renewable solid fuels as a viable substitute for fossil fuels in household energy needs.

98/00527 Combustion and inorganic emissions of ground waste tires

Carbon, sulfur and nitrogen oxide emissions from combustion of pulverized raw and torrefied biomass

In the coal mining industry, the coal quality is as crucial as the coal quantity because it can impact the coal usefulness. The quality of coal itself can be influenced by several factors, such as moisture content, ash, sulfur, and volatile matter. This study tries to understand the coal quality and its variation in the Muara Enim Formation of South Sumatra Basin. The research was conducted in the West Banko field, PT. Bukit Asam, Tbk., Tanjung Enim, South Sumatra. By using linear regression, this study found that increasing ash and total moisture content will lead to a decreasing amount of the calorific value. Additionally, the value of coal quality content such as ash and total moisture can be affected by the depositional environment, sedimentation rate, and coal characteristics in the study area thus affecting the calorific value. Transitional lower delta plain depositional environment with low sedimentation rate and coarsening upward sandstone sequence indicates lower ash and total moisture content in the study area. The highest calorific value found in the study area is in C1 seam, this can be seen from the ash quality and total moisture distribution map which inversely proportional to the calorific value.

Air and oxy-fuel combustion behaviour of petcoke/lignite blends

ABSTRACTRecognizing the fact that 5% of annual global primary production of biomass should cover 50% of the world’s current primary energy demand, plants widely available in Turkey, such as Astragalus, great mullein and sunflower, have been pelletized mixed in specific amounts to investigate their burning behaviors versus other fuels. Taguchi method was used to obtain a pelletized fuel with maximum calorie, low humidity, and low ash. Results suggested that the pellet has low humidity and ash content, while its caloric value is greater than that of the pomace, lignite, wood, sawdust, or animal and plant wastes used as fuel.

This work is dedicated to the co-pyrolysis of real waste high density polyethylene (HDPE) and biomass (rice straw) obtained from agriculture. Mixtures of raw materials were pyrolyzed in their 0%/100%, 30%/70%, 50%/50%, 70%/30%, 100%/0% ratios using a thermograph. The atmosphere was nitrogen, and a constant heating rate was used. Based on weight loss and DTG curves, the apparent reaction kinetic parameters (e.g., activation energy) were calculated using first-order kinetic approach and Arrhenius equation. It was found that decomposition of pure plastic has approximately 280 kJ/mol activation energy, while that of was considerably less in case of biomass. Furthermore, HDPE decomposition takes by one stage, while that of biomass was three stages. The larger amount of raw materials (100 g) were also pyrolyzed in the batch rig at 550°C to obtain products for analysis focussing to their long-term application. Pyrolysis oils were investigated by Fourier transformed infrared spectroscopy and standardized methods, such as density, viscosity, boiling range determination. It was concluded, that higher plastic ratio in raw material had the advantageous effect to the pyrolysis oil long-term application. E.g., the concentration of oxygenated compounds, such as aldehydes, ketones, carboxylic acids or even phenol and its derivate could be significantly decreased, which had an advantageous effect to their corrosion property. Lower average molecular weight, viscosity, and density were measured as a function of plastic content.