Low Calorific Value Research Articles

Study of the effect of a bulking agent on the biodrying of municipal solid waste

The characteristics of municipal solid waste in Indonesia tend to be wet and have a low calorific value. Therefore, a pre-treatment process is needed to dry the municipal solid waste before converting it into RDF. Biodrying is one of the solid waste drying methods that can be used for this purpose. This study aims to determine the effect of variations in bulking agents on the biodrying performance of municipal solid waste and to compare the resulting product with RDF standards. Reactor 1 consists of 100% organic waste without a bulking agent. Reactors 2, 3, and 4 contain organic waste mixed with straw, wood shavings, and rice husks, respectively, as bulking agents. The experiment lasted for 30 days. Measurements were taken for solid waste mass, temperature, moisture content, calorific value, proximate analysis (including volatile solids, fixed carbon, and ash content), and ultimate analysis. Statistical analysis of the test parameters showed that the addition of bulking agents significantly affected the moisture content and fixed carbon levels. A comparison between the biodrying results and RDF standards from several references shows that the biodried waste only meets RDF requirements for volatile content, chlorine, and sulfur. Among the variations tested, the organic waste mixed with straw (Reactor 2) yielded the most optimal results compared to other variations, with a moisture content of 54.33% (wet basis) and a calorific value of 5.4 MJ/kg.

The Caloric Value of Municipal Solid Waste Generated in Georgia for Energy Recovery

Waste management approaches such as prevention, reuse, recycling, and recovery are key objectives, which stand in a Waste hierarchy of priority. The same Waste Hierarchy is a basic principle of the waste management policy of Georgia. Waste recovery is a priority approach over landfilling. In this case, it should be noted that more than 90 % of waste generated in Georgia is landfilled, which has negative social, economic, and environmental impacts. Thus, along with reusing and recycling, Waste-to-Energy (WtE) should be a solution for sustainable WM systems. Municipal waste generation in Georgia is characterized by increasing dynamics. For example, in 2015–2023, waste generation per capita increased from 207.8 kg to 302.2 kg. Accordingly, the amount of municipal waste disposed of in landfills has significantly increased. According to data from the National Statistics Office of Georgia, in 2015, 774.4 thousand tons were placed in landfills, and in 2023 – 1116.6 thousand tons, which is more than 90 % of the municipal waste generated annually. On the other hand, the calorific value of municipal waste generated in Georgia is of interest in terms of energy recovery, taking into account the experience of many developed countries, in particular Sweden and Denmark. As is known, for the effective use of municipal waste for energy recovery, it is necessary that the average lower calorific value of waste should be at least 7 MJ/kg and must never fall below 6 MJ/kg. Plastic waste is characterized by the highest calorific value, paper and textiles are also acceptable for energy recovery. Organic waste has a rather low calorific value (4 MJ/kg), which is not recommended for Waste-to-Energy technologies. Plastics such as Polypropylene PP, Polyethylene HDPE, and Polyethylene Terephthalate PET have a high calorific value. In this regard, it should be noted that municipal waste generated in Georgia consists of about 13–14 % plastic, 10–11 % of paper and cardboard, and more than 4 % of textiles. Organic waste constitutes the largest portion of municipal waste generated in Georgia (over 54 %), however, this type of waste is not of interest in terms of energy recovery, as the calorific value of organic waste is very low (4 MJ/kg).

Co-combustion of multiple blends of coal, sewage sludge, and bamboo: thermal behaviors, kinetic evaluation, and heavy-metal migration

The co-combustion of sludge and coal in power plant boilers is widely employed to address waste-disposal challenges. Sludge, however, is characterized by its low calorific value and high heavy-metal content. This study demonstrates that incorporating bamboo into coal and sludge mixtures for ternary co-combustion can significantly improve combustion performance. Thermogravimetric experiments indicate that adding bamboo reduces the ignition temperature and accelerates the combustion rate. At a mass ratio of 95:5:5 (coal:sludge:bamboo), the comprehensive combustion characteristics are enhanced, and activation energy is reduced compared to coal alone. Ash analysis highlighted significant synergistic interactions during co-combustion. At 1000 °C, the concentrations of Cu, Zn, As, Cr, and Mn in the ash were elevated by 57.6%, 58.1%, 6.6%, 11.89%, and 3.6%, respectively, relative to combustion without bamboo. Thermodynamic equilibrium calculations combined with experimental data suggest that heavy metals are stabilized through the formation of stable compounds or encapsulation within inorganic matrices. This study provides theoretical guidance for cleaner combustion in power plants, promoting improved biomass utilization, enhanced fuel efficiency, and mitigation of heavy-metal emissions.

Wet torrefaction of Indonesian agricultural waste biomass: product evaluation and analysis of slagging-fouling potential

Abstract 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.

Agri-Eco Energy: Evaluating Non-Edible Binders in Coconut Shell Biochar and Cinnamon Sawdust Briquettes for Sustainable Fuel Production

This study investigates the production of biomass briquettes using waste coconut shell charcoal and cinnamon sawdust, bound by eco-friendly, non-edible binders: cassava peel starch, giant taro starch, and pine resin. The production process involved carbonization of coconut shells, followed by crushing, blending with sawdust, pressing, and a 12-day sun-drying period. The briquettes were tested for calorific value, density, compressive strength, and shatter resistance. The calorific values ranged from 26.07–31.60 MJ/kg, meeting the industrial standards, while densities varied between 0.83 g/cm3 and 1.14 g/cm3, ensuring compactness and efficient combustion. Among the binders, cassava peel starch provided the best bonding strength, resulting in high-density briquettes with superior durability and energy release, showing a calorific value and compressive strength of 2.11 MPa. Giant taro starch also improved durability, though with slightly lower calorific values but better bonding than pine resin. Pine resin, while contributing to high calorific values, reduced compressive strength with increased resin content, making it less suitable for high mechanical strength applications. Proximate analysis revealed that cassava peel starch-based briquettes had moisture content from 6.5% to 8.6%, volatile matter from 15.2% to 23.5%, ash content from 2.1% to 3.2%, and fixed carbon between 69% and 76.2%. Giant taro starch-based briquettes exhibited 63.2% to 75% fixed carbon, while pine resin-based briquettes had the highest fixed carbon content (66.4% to 78.3%), demonstrating the potential of non-edible adhesives for sustainable, high-performance fuel production.

Fire and Fire Mitigation by Low-Fuel Building Products

Fire is a combustion reaction where fuel reacts with oxygen in the presence of heat, releasing energy as light, heat, and flames. The main components of fire are fuel, oxygen, and heat. All three components must be present to cause a fire. Fire is a significant threat to residential and commercial buildings, often intensified by high fuel content in building materials such as wood and synthetics. This paper summarizes fire types and damages, loss of property and life, fuel content in building materials, and a method to reduce fire risk by minimizing the building material’s fuel content. This method uses minerals (coal combustion residual (CCR)), primarily inorganic oxides bonded with a small percentage of polyurethane binder, to manufacture a composite material moldable into multiple building products. The composite was tested as per the ASTM for mechanical, thermal, and fire safety performance. ASTM D635-based fire testing showed self-extinguishing behavior with significantly reduced burn rate and lengths (1–2 mm). A low calorific value of 6.6 MJ/kg was determined separately. The test results demonstrate that CCR-based mineral composites offer a fire-resistant, structurally sound, and eco-friendly alternative to wood products. This research supports recycling inorganic minerals into fire-resistant building products that enhance safety.

Impact of Ethanol–Diesel Blend on CI Engine Performance and Emissions

The aim of this study was to assess the impact of adding ethanol to diesel fuel on particulate matter (PM) and nitrogen oxides (NOx) emissions in the Perkins 854E compression-ignition engine. Tests were carried out under European Stationary Cycle (ESC) conditions using the Horiba Mexa 1230 PM analyzer (HORIBA, Ltd., Kyoto, Japan) for particulate measurement and the AVL CEB II analyzer (AVL, Graz, Austria) for NOx concentration. The engine under investigation featured direct injection, turbocharging, a common-rail fuel supply system, and complied with the Stage IIIB/Tier 4 emission standard. Two types of fuel were used: conventional diesel fuel (DF) and diesel with a 10% ethanol additive by volume (DFE10). In addition to emissions measurements, key engine performance parameters, such as torque, effective power, and fuel consumption, were analyzed. The ESC test was specifically chosen to isolate the influence of the fuel’s properties by avoiding the effects of changes in combustion control strategies. Due to the lower calorific value of DFE10 compared to DF, a slight increase in fuel consumption was observed under certain operating conditions. Nevertheless, overall engine performance remained largely unchanged. The test results showed that the use of DFE10 led to a significant 44% reduction in particulate matter emissions and a moderate 2.2% decrease in NOx emissions compared to conventional diesel fuel. These findings highlight the potential of ethanol as a diesel fuel additive to reduce harmful exhaust emissions without negatively affecting the performance of modern diesel engines.

Experimental Evaluation of the Impact on Turbo Engine’s Performance and Gaseous Emissions While Using n-Heptane Octanol/Jet-A Blends

This paper investigates how octanol, used as a renewable additive in Jet A fuel, influences the performance and emissions of aviation micro-turbo engines. Blends containing 10%, 20%, and 30% octanol, with an additional 5% n-heptane, were tested to closely replicate Jet A’s physical–chemical properties. Mathematical models validated using density and viscosity data achieved accurate predictions, with maximum absolute errors of 0.0018 g/cm3 for density and 0.4020 mm2/s for viscosity. Performance assessments showed that fuel consumption increased due to octanol’s lower calorific value, requiring higher fuel flow to sustain engine speed. Combustion temperature variations ranged from a decrease of 5.38% in Regime 1 (30% octanol) to increases of up to 1.47% and 1.13% in Regimes 2 and 3, respectively, without compromising engine stability. Thrust variations were minimal, with decreases up to 0.72% observed at 30% octanol concentration. Emission analysis indicated significant reductions in CO and NOx levels with increased octanol content, attributed to enhanced combustion completeness and additional oxygen availability. SO2 emissions also decreased slightly due to the lower sulfur content. Thermal efficiency marginally declined from 5.04% (Jet A) to approximately 4.92–4.97% for octanol blends. These findings support octanol as a viable sustainable additive, offering substantial emission benefits with only minor efficiency trade-offs.

Numerical Simulation of Combustion Characteristics of Low Calorific Value Fuel Treated by Double-Layer Porous Medium Burner

ABSTRACT To explore the safe and efficient utilization of low calorific value fuel resources, this study conducted numerical simulations of the combustion process within a dual-layer porous media burner, focusing on temperature distribution, and radiation efficiency. The study analyzed the effects of particle packing structure and inlet methane parameters (velocity and concentration) on combustion characteristics. The results indicated that even with low-concentration methane, the outlet temperature of the dual-layer porous media burner exceeded 1000 K under stable combustion, with strong radiative capability at the outlet surface. Parametric studies of thermal properties revealed that reducing thermal conductivity helps anchor the flame near the interface of the two particle layers, enhancing combustion stability. With increasing inlet velocity and equivalence ratio, the outlet radiation efficiency improved to the range of 10% to 20%. Despite lower efficiency, large-scale adoption remains economically viable due to vast coal-associated gas reserves, enabling cost-effective resource utilization.

Numerical Simulation of Hydrogen Mixing Process in T-Junction Natural Gas Pipeline.

As a cost-effective transitional strategy, the integrated utilization and transportation of hydrogen and natural gas have gained significant attention as a viable pathway toward carbon neutrality. However, hydrogen's low density, viscosity, and calorific value cause upward migration and accumulation in pipelines, raising embrittlement risks. Its high diffusion and leakage rates also pose significant safety challenges. To address hydrogen-natural gas blending challenges, achieving uniform mixing is crucial. This study systematically examines hydrogen-methane mixing in T-junction pipelines via numerical simulations, analyzing hydrogen mixing ratios (HMR: 10-25%) and methane flow rates (4-10 m/s) to assess flow and mixing dynamics. The coefficient of variation (COV) quantifies mixing uniformity with spatial and temporal analyses, optimizing hydrogen injection for rapid, homogeneous mixing. The key findings are as follows: (1) The uniform mixing length (the minimum axial distance required for the first pipeline cross-section to achieve 95% mixing uniformity) decreases inversely with the HMR, from 100 D to 20.875 D (D represents the pipeline diameter) as the HMR rises from 10% to 25%. (2) Analysis of initial uniform mixing time (defined as the duration required for the first pipeline cross-section to achieve 95% mixing uniformity) shows significant reduction with increasing HMR. While methane flow rate has a less pronounced effect, it nevertheless contributes to reducing the outlet uniform mixing time (defined as the time required to attain 95% mixing uniformity at the pipeline outlet). (3) A fundamental trade-off in engineering applications is established: increasing the HMR reduces mixing length but extends overall mixing time (difference between outlet and initial mixing times), while higher methane flow rates shorten overall mixing time at the cost of increased mixing length. The primary objective of this research is to elucidate the fundamental fluid dynamics of hydrogen-methane mixtures in T-junction pipelines, providing scientific insights for the safe and efficient operation of hydrogen-blended natural gas pipeline systems.

Pengaruh Performa Mesin Diesel Berbahan Bakar Crude Palm Oil (CPO) dan B35 Terhadap Variasi Pembebanan

One use of alternative fuel that has the potential to be developed currently is crude palm oil (CPO). However, the use of CPO must go through a series of direct tests before it is widely applied. So the aim of this research is to carry out tests related to the use of CPO fuel and determine the effects in terms of engine performance and exhaust emissions. The fuel used in this research is CPO and B35 as existing fuel. The method used is an experimental method, through direct observation and measurement of phenomena when CPO fuel is tested for performance and exhaust emissions. The research used a diesel engine coupled to a generator and loaded with halogen lamps. The loading varies, namely 0.5; 1; 1.5; 2; 2.5; 3; 3.5; 4; up to 4.5 kW. Based on research results, the use of CPO fuel in general will produce higher power, torque and SFC, namely 2.55% each; 2.55%; and 17%. However, when comparing the thermal efficiency, hydrocarbon (HC) emissions and smoke opacity of CPO fuel, it produces a lower value of 10.54%; 15.4%; and 72% compared to B35 fuel engines. This is generally influenced by CPO fuel which has a lower calorific value, viscosity value and higher density than B35.

Experimental study on stable combustion performance of a novel blast furnace gas burner

ABSTRACT To solve the problems of low calorific value gas such as blast furnace gas, such as difficult ignition, unstable combustion and low flame temperature, a novel 4.5 MW blast furnace gas burner was proposed in this study. The burner integrates the technologies of swirl combustion, blunt body combustion, regenerative combustion, rich-lean combustion and cross injection. The burner prototype was scaled down to a 15 kW burner model. Cold and hot tests were conducted to investigate the effects of nozzle structure and operation load on the flow and combustion characteristics of the burner. The results demonstrate that the burner has good stable combustion performance for low-calorific value gas, with a minimum calorific value of 3893.1 kJ·m−3. The radial wind design enhances gas mixing and axial velocity, leading to stronger jet strength and longer flame length. Compared with conventional designs, the air cross-flow nozzle achieves higher peak temperatures (1420 ℃), faster fuel and oxygen consumption, higher burnout rates, and combustion efficiency up to 99.99%. The burner also shows excellent load adaptability, with stable core temperatures and combustion efficiency that is consistently above 99.3%.

A Comparative Study of Methanol and Methane Combustion in a Gas Turbine Combustor

To investigate the combustion and emission characteristics of a 20 MW gas turbine combustor following fuel replacement, this study employs numerical simulations to systematically compare the combustion performance of methanol and methane. The focus is on the influence mechanism of the fuel distribution ratio on NOx emissions. As a preliminary numerical investigation, this study aims to provide theoretical guidance for subsequent experimental research, with the results serving to define measurement points in experimental design. It is found that the value of NOx emission from methanol combustion is 40–78% of that of methane under all operating conditions, which is significantly lower than that of methane. And its low NOx emission range is significantly wider than that of methane (methanol: a pilot fuel ratio range of 1–12%; methane: a pilot fuel ratio range from 2 to 4%). Methanol reaches the lowest NOx emission (51.53 ppm) near the pilot fuel ratio of 2%, while methane reaches the lowest NOx emission (93 ppm) near the pilot fuel ratio of 4%. This difference is due to the oxygen content and low calorific value of methanol, which makes it easier to reduce the flame in the main combustion zone to the temperature that inhibits the generation of thermal NOx, so there is no need to allocate more fuel to the pilot to reduce the cooling pressure in the main combustion zone. In addition, the combustor efficiency of methanol is higher and less volatile (99.52–99.89%), which is slightly higher than that of methane (99.33–99.61%). The results show that methanol is suitable as a gas turbine fuel. Its performance in the gas turbine combustor is slightly better than that of methane, and NOx emission is significantly better than that of methane. The better performance of methanol provides greater flexibility for the design of gas turbine combustors and has great feasibility in engineering.

COMPARATIVE PERFORMANCE STUDY OF A MODIFIED GASOLINE ENGINE WITH THROTTLE-VALVE-DRIVEN MECHANICAL HYDROGEN INJECTOR

In this study, a single-cylinder, air-cooled, 4-stroke, spark-ignited internal combustion engine was modified to operate with both gasoline and gas-phase hydrogen. The engine cylinder cover was redesigned, and an enhanced mechanical hydrogen injector was attached to it. Measurement devices capable of capturing all critical test parameters for comparison purposes were integrated into the test engine. Additionally, all necessary safety equipment was adapted to ensure the safe delivery of hydrogen to the engine. The engine was initially tested with gasoline, and values for engine torque, brake power, specific fuel consumption, TE, and VE were recorded at air throttle openings of 20º to 90º in 10º increments and speeds ranging from 1000 to 3900 rpm. The same parameters were then measured using gas-phase hydrogen. In the experiments conducted with gasoline, optimal performance was achieved at air throttle openings of 60º to 90º and engine speeds of 2350 to 3400 rpm. In the experiments using hydrogen, the most favorable values were observed between 1300 and 1775 rpm at a 30º air throttle opening. When comparing the performance of gasoline and hydrogen in the same engine, results indicated that using gaseous hydrogen led to a 79.54% reduction in engine power and a 73.44% decrease in engine torque. This reduction is considered typical, given that the lower calorific value of hydrogen in the gas phase, at the same pressure and temperature (1 bar, 20 ºC), is approximately 0.010 MJ/l, compared to around 34 MJ/l for gasoline. During testing, issues such as knocking, pre-ignition, and backfire typically associated with intake manifold injection did not occur. No prior studies have employed a direct hydrogen injection method into the combustion chamber with a mechanically activated Hydrogen Injector driven by the intake valve.

Numerical Modeling and Performance Evaluation of a New Biogas Purification System

In order to meet the challenges posed by dependence on fossil fuels, it is essential to develop an energy alternative based on renewable sources. Among alternative energy solutions, biogas occupies a prime position. However, before biogas can be used, it must be purified, which involves removing the carbon dioxide (CO<sub>2</sub>) and recovering the methane (CH<sub>4</sub>), thereby increasing the calorific value of the methane. The most innovative purification solution is cryogenics. Our aim in this work is to use cryogenics to purify biogas by liquefying the carbon dioxide it contains. To achieve this, we have designed and dimensioned the various components of a cryogenic purification unit for biogas production. Using the incremental method based on heat conservation equations, we simulated this purification process on the Aspen plus calculation code. Using the ADMI calculation code, we modeled the model equations to visualize the behavior of the various parameters to be controlled. The temperature, pressure and mass flow profiles affecting the desublimation of carbon dioxide were obtained. Furthermore, the sizing results show that a 450 W compressor and a condenser with a capacity of 2.5 kg are required. The temperature and pressure of the biomethane and carbon dioxide at the condenser outlet are -130°C and 15 bars. Simulations show curves for variations in temperature, pressure, rate of bio-methane recovery and carbon dioxide evacuation. They show that it is possible to produce biomethane with a purity of 96%, with a very negligible amount of carbon dioxide and a high lower calorific value (LCV) than raw biogas (9.83 kWh/m<sup>3</sup> higher than 6 kWh/m<sup>3</sup>), a significant value in energy terms, showing that this biomethane could be used for a variety of purposes.

Analysis of Cylinder Pressure and Heat Release Rate Variation in Diesel Engine Fueled with Croton Macrostachyus (CMS) Seed Oil Biodiesel as an Alternative Fuel

Despite its higher density, viscosity, and lower calorific value, biodiesel has been explored as an alternative energy source to diesel fuel. This study investigated biodiesel produced from croton macrostachyus (CMS) seed, a non-edible feedstock. The research aimed to experimentally analyze cylinder pressure, heat release rate, and ignition delay, as well as engine performance and emission characteristics, at a constant speed of 2700 rpm under varying loads (0–80%) using diesel, B10, B15, B20, and B25 blended fuels. Among the tested blends, B25 exhibited superior performance, achieving the highest peak cylinder pressure (CP) of 58.21 bar and a maximum heat release rate (HRR) of 543.9 J/CA at 80% engine load. Conversely, B20 at 60% engine load, followed by B25 and pure diesel at 80% engine load, demonstrated the shortest ignition delay (ID) and the most advanced start of combustion (SoC). Compared to the biodiesel blends, pure diesel showed: a 5.5–14% increase in brake thermal efficiency (BTE), a 17–26% decrease in brake-specific fuel consumption (BSFC), and a 7–12% reduction in exhaust gas temperature (EGT). Regarding emissions, carbon monoxide (CO) and hydrocarbon (HC) emissions were lower for pure diesel, while carbon dioxide (CO2) and nitrogen oxide (NOx) emissions were higher for biodiesel blends, attributed to their inherent oxygen content. In conclusion, CMS biodiesel displays promising characteristics, suggesting its potential suitability for use in internal combustion engines.

Heat transfer analysis of premixed low calorific value landfill gas impinging flame under oxygen and hydrogen enrichment

Heat transfer analysis of premixed low calorific value landfill gas impinging flame under oxygen and hydrogen enrichment

Use of pine needles for producing high-calorific value bio-briquettes and pine resin for biomass boiler

Biomass, ranked as the fourth-largest energy source globally, presents a viable renewable energy option. However, inherent limitations such as low density and calorific value necessitate the development of quality-enhanced biomass, like biomass briquettes, for more efficient energy production. This study focuses on biomass briquette production using pine needles, abundant in the hilly regions of Sri Lanka, as a forestry waste-to-energy concept. The research aims to investigate the physicochemical properties of pine needles char for biomass briquette preparation and utilizing pine resin as a binding agent. Thermal degradation analysis, XRD tests, and physical property assessments were performed on raw materials and briquettes. The objectives include pine resin extraction and analysis of pine needles' properties, optimization of briquette composition to ensure high combustion efficiency and comparison of briquette properties with standards relevant to biomass. Results revealed that pine needle char possesses favorable characteristics for briquetting, with a moisture content of 6.105% and ash content of 4.233%. The 5:1 ratio briquette showed the best performance with a calorific value of 22.19 MJ/kg, a high density of 917.272 kg/m³, and a compression ratio of 3.507. Pine needle briquettes (PNB) were made with different ratio pine needles char and binder using a small-scale hydraulic press (2 tons; 5.5 MPa) with a honeycomb-type mold. The machine's estimated production capacity is 192 briquettes per day. The research results help to create inventive waste management solutions by transforming pine needles into valuable energy sources, benefiting the environment, industries, and self-employed individuals equally. KEYWORDS: Bio-Briquette, bio-char Calorific value, Pine Needle, Pine resin, Renewable energy

Hexaazatrinaphthylene-Based Ultrastable Metal-Organic Frameworks Modulated by the Chelating Coordination Configuration for CO2 Capture.

Hexaazatrinaphthylene (HATN), a polyheterocyclic aromatic ligand, is ideal for constructing discrete functional coordination complexes. However, its conjugated rigidity has resulted in a great challenge in forming extended structures with only one 3D metal-organic framework (MOF) reported 24 years ago. Herein, by regulation of the dihedral angle between two chelating HATN planes, three new porous HATN-based MOFs (SNNU-231-233) with mononuclear metal centers were successfully synthesized. SNNU-231, a unique 2-fold interpenetrated MOF, was first assembled, but the interpenetration leads to the lost pores. By modulating coordination configurations, the pore channels were successfully opened in SNNU-232 and SNNU-233, leading to a new topology in SNNU-232 and breaking the interpenetration in SNNU-233. All HATN-based MOFs exhibit exceptional thermal stability above 500 °C, surpassing most reported MOF materials. At the same time, SNNU-233 can keep its structure in water from pH = 1 to 14. Specifically, SNNU-233 had outstanding CO2 uptake capacity and separation ability of CO2/N2 due to its strong affinity to CO2 molecules in specific pores with abundant hydrogen bonds and π-force adsorption sites. SNNU-233 also showed significant potential for the simulated low calorific value coal gases with five components of H2 (5.1%), CO (9.1%), CH4 (5.0%), N2 (66.3%), and CO2 (14.3%).

Performance Evaluation of Inulin‐Modified Propellant for Fire Safety Applications

ABSTRACTTraditional aerosol‐forming composites consist of a combination of potassium chlorate/nitrate and synthetic resins, such as epoxy, polyurethane, phenol‐formaldehyde, and melamine‐formaldehyde. The application of these synthetic organic resins has been restricted due to their severe flammability and accompanying life‐threatening work hazard, despite their good mechanical and adhesive capabilities. The combustion flame of these compositions can reach temperatures of up to 2100°C, which might result in secondary fire hazards in explosive environments, such as oil‐producing platforms and ship engine rooms. This study aimed to investigate the ability of naturally occurring polysaccharide inulin to reduce the exothermicity of potassium nitrate/chlorate‐based pyrotechnic composites. In the present work, we newly developed a pyrotechnic composition (PyC) that employed inulin as a reducer instead of synthetic resin. Its thermal characteristics, fire‐extinguishing efficacy, and combustion behavior were compared to traditional PyCs based on phenolic resin. Although the fire suppressing performance of the novel and old PyCs is equivalent, the newly created composition demonstrated a 71% lower combustion flame temperature, a faster burn rate, and a lower calorific value. Several techniques, including HRXRD, SEM, FTIR, and EDX, were used to characterize the physical and chemical properties of the discharged aerosol in order to comprehend the fire‐extinguishing mechanism.