Decrease In Calorific Value Research Articles

Numerical Analysis of the Effect of Ethanol-Gasoline Blends on a Single-Cylinder Spark-Ignition Engine Performance and Emissions

— With the rapid increase in the number of vehicles fueled by gasoline plying on the roads, there has been a rising need in the search for alternative fuels, which are more environmental friendly in order to reduce the amount of vehicular exhaust emissions. This can be achieved by using blended mixtures of gasoline with alcoholic fuels among which, ethanol is found to be most suitable due to its easy availability, low costs, safety and low impact on the engine performance. This study aims to investigate the performance of a single-cylinder, four-stroke spark-ignition engine using different ethanol-gasoline blends, namely E0, E10, E20 and E30. The engine's torque, brake power, brake thermal efficiency, brake-specific fuel consumption, and exhaust emissions were analysed using numerical simulation. Results revealed that raising the proportion of ethanol in the fuel mixture resulted in reduced brake power and torque upto 16% as a result of decrease in calorific value of the mixture. The engine's brake thermal efficiency decreased by upto 3% while the brake-specific fuel consumption increased upto 12% with increase in ethanol concentration. Exhaust emissions, including NOx and HC, were found to be influenced by engine speed, with NOx emissions increasing and HC emissions decreasing as speed increased. The study also revealed that increasing ethanol concentration in the fuel resulted in reduced engine exhaust emissions by upto 47% and 10% for NOX and HC emissions respectively. The study concluded that among all the blends used, optimum performance was obtained for E30 blend with reduction in exhaust emissions but at the expense of slight reduction in engine performance.

Effect of storage conditions on lignocellulose biofuels properties

This article examines the effects of different storage conditions on selected physicochemical properties of three types of agro-biomass pellets: sunflower husks, wheat straw and hemp hurds, and wood pellets. The tests were carried out in a climatic chamber, which allows simulation of real storage conditions, i.e. conditions with high air humidity and variable (±) ambient air temperatures. The results showed higher degradability of agro-biomass pellets compared to woody biomass. The pellets degraded to a less extent at varying ± temperatures than at high humidity (90% RH). After complete moisture saturation, durability decreases for agro-pellets by an average of 9%, while after freezing and defreezing for sunflower husk pellets and woody pellets durability decreases by 2%, and for hemp hurd pellets by 11%. In contrast, strength-by-dropping index for agro-pellets decreased by 20% after being in the environment (30 °C and 90%RH) and 15% under varying temperature conditions. No change in the energy parameters of all pellets in the dry matter was noted. On the other hand, an increase in the moisture content of pellets when they are stored under different environmental conditions results in a decrease in calorific value.

Effect of Salt-Induced Stress on the Calorific Value of Two Miscanthus sacchariflorus (Amur Silvergrass) Varieties

This study was designed to investigate the relationship between the caloric value and salt tolerance of two varieties of Miscanthus sacchariflorus (Amur silvergrass: M127 and M022). The salt tolerance capacity, photosynthetic characteristics, Na+ and K+ uptake by the roots and aboveground parts, and caloric value of different parts of the aboveground parts were obtained under hydroponic conditions. The results showed that M022 was more tolerant to salt stress than M127 and the former had a higher photosynthetic efficiency as well as a lower aboveground Na+ accumulation, K+ efflux, and larger K+/Na+ ratio. The calorific values of stems, spear leaves, aging leaves, and functional leaves of the two varieties showed a decreasing trend with increasing NaCl concentration. At 270 mM NaCl, the calorific values of the stems, aging leaves, functional leaves, and spear leaves was reduced by 18.10%, 46.73%, 26.11%, and 18.35% for M022 and 41.99%, 39.41%, 34.82%, and 45.09% for M127 compared to the controls, respectively. We observed that the aging leaves of M022 had a faster decline rate in calorific value than those of M127, indicating that the aging leaves of M022 preferentially isolated the harmful Na+ ion, reduced its accumulation in other parts, and increased the K+/Na+ ratio in the corresponding parts, thus inhibiting the decrease in calorific value. Following this result, it can be inferred that M022 inhibited the decline in calorific values during stress by efficiently compartmentalizing the distribution of Na+ and K+. Our results provide a theoretical basis and technical support for the efficient cultivation of salt-tolerant energy plants in saline–alkaline soil.

Co-pyrolysis of plastic waste and eucalyptus waste wood for fuel pellets production: A study of fuel, mechanical, and combustion characteristics under varying binder proportion

The study explores the effect of varying molasses proportions as a binder on the characteristics of densified char obtained through the slow co-pyrolysis of plastic waste and Eucalyptus wood waste (Waste low-density polyethylene – Eucalyptus wood (WLDPE–EW) and Waste Polystyrene – Eucalyptus wood (WPS–EW)). Pyrolysis was conducted at 500 °C with a residence time of 120 min, employing plastic to wood waste ratios of 1:2 and 1:3 (w/w). The focus was on how varying the proportion of molasses (10–30 %), influences the physical and combustion properties of the resulting biofuel pellets. Our findings reveal that the calorific value of the pellets decreased from 28.94 to 27.44 MJ/Kg as the molasses content increased. However, this decrease in calorific value was compensated by an increase in pellet mass density, which led to a higher energy density overall. This phenomenon was attributed to the formation of solid bridges between particles, facilitated by molasses, effectively decreasing particle spacing. The structural integrity of the pellets, as measured by the impact resistance index, improved significantly (43–47 %) with the addition of molasses. However, a significant change in the combustion characteristics depicted by lower ignition and burnout temperatures were observed due to decrease in fixed carbon value and increase in volatile matter content, as the proportion of molasses increased. Despite these changes, the pellets demonstrated a stable combustion profile, suggesting that molasses are an effective binder for producing biofuel pellets through the densification of char derived from the co-pyrolysis of plastic and Eucalyptus wood waste. The optimized molasses concentration analyzed through multifactor regression analysis was 16.96 % with 28 % WLDPE proportion to produce WLDPE–EW char pellets. This study highlights the potential of using molasses as a sustainable binder to enhance the mechanical and combustion properties of biofuel pellets, offering a viable pathway for the valorization of waste materials.

Effects of multi-strain pretreatment on thermochemical properties and component structure of paulownia

This study aims to delve into the impact of long-term multi-strain pretreatment on the thermochemical characteristics of paulownia. The nine-month experimental analysis reveals that the fourth month marks a crucial turning point in the pretreatment process. From Stage I (0–4 months) to Stage II (4–9 months), the pyrolysis temperature range continuously narrows, reducing a maximum of 31.47%. The char yield initially increased by 10.25% and then decreased by 6.95%. Calorific value showed a slow initial decline of 3.98–4.08%, followed by a subsequent increase of 7.66%. The ignition point continued to rise by 5.61%− 5.78%. The compositional experimental results indicate that in the first stage, strain primarily depolymerize the high-polymer lignin, resulting in a decrease in calorific value. The increase in the relative content of syringyl lignin (S) contributes to the rise in char yield. In Stage II, the S units are converted into guaiacyl lignin (G), which has a lower char yield, while the exposed hemicellulose and cellulose undergo severe erosion. The relative content of lignin and enzymatic products with stubborn structures increases, leading to an increase in calorific value. However, the higher breaking temperature of bonds in these structures results in a continuous increase in the ignition point. This study clearly establishes that after nine months of pretreatment, the paulownia exhibits characteristics of rapid pyrolysis, high calorific value and ignition point, which provides a reliable basis for uncovering the potential reuses of paulownia.

Effects of Coal Desulfurization on Ultimate, Proximate, Calorific Value and Functional Group Transformations

Coal desulfurization is essential for addressing environmental concerns about air quality, human health, and climate change. In this study, coal treated with potassium carbonate (PC)-ethylene glycol (EG) at a molar ratio of 1:8 for 60 minutes at 30 °C achieved a 40.24 % reduction in sulfur content. The ultimate analysis revealed reductions in carbon, hydrogen, and nitrogen content but an increase in oxygen concentration. The proximate analysis showed a significant decrease in the volatile matter, indicating the transformation of the coal’s aromatic and long-chain hydrocarbons into shorter-chain hydrocarbons. Additionally, the treatment increased the fixed carbon content, suggesting better heat generation during combustion and improved coal quality. Although the proximate analysis has implications for calorific value, the decrease in calorific value for the treated coal was mainly due to the reduction in sulfur content. The Fourier Transform Infrared Spectroscopy (FTIR) detected changes in peak positions for aromatic C=C, thiophene, and organic sulfates. The peaks for thiophene and organic sulfates showed a shift to higher wavenumbers, indicating that the PC: EG mixture effectively removed sulfur from coal. This study demonstrates a promising approach towards meeting the safety and environmental targets outlined in the 2030 Agenda for Sustainable Development.

Correlation between Physical Properties and Specific Fuel Consumption in Jatropha -Used Cooking Oil Biodiesel Mixtures

This study was motivated by the need to understand the influence of using waste jatropha biodiesel on the physical properties of fuel and the performance of diesel engines. The primary aim was to determine the relationship between the fuel's physical properties, spray angle, and specific fuel consumption (SFC) at various load levels. The methodology employed included measurements of density, viscosity, flash point, calorific value, spray angle, and SFC for different blends of waste jatropha biodiesel and diesel (B5, B10, B15, B20). The research results demonstrate an increase in density, kinematic viscosity, and flash point, along with a decrease in calorific value, as the biodiesel content increases. The density of the biodiesel mixture ranges from 823 kg/m³ at B5 to 836.50 kg/m³ at B20. The kinematic viscosity increases from 3.9 cSt at B5 to 5.2 cSt at B20, and the flash point rises from 112.9°C at B5 to 128.7°C for B20. Meanwhile, the calorific value decreases from 10308.2670 cal/g at B5 to 10133.8280 cal/g for B20. A strong correlation exists between density and kinematic viscosity with the spray angle, exhibiting R2 values of 0.9141 and 0.8287, respectively. The correlation between the fuel's physical properties and the specific fuel consumption (SFC) is also substantial, marked by high R2 values above 0.93. These findings provide a solid foundation for the development of more optimal biodiesel formulations.

Improving fuel quality from plastic bag waste pyrolysis by controlling condensation temperature

Plastic waste is a major problem in many areas around the world. The pyrolysis of plastic waste to produce fuel is another solution to this problem. But the fuel obtained from plastic waste was of low quality due to improper experimental factors. Therefore, the improvement of fuel quality in the production process is essential. This research has objective was to study the first condenser temperature in 5 levels: 10, 20, 30, 40 and 50 °C. The experimental conditions were pyrolysis temperature of 300 °C, hot filter temperature of 200 °C, second condenser temperature of -40 °C, 1 kg of plastic bag waste and the experimental period of 2 h. The results showed that the first condenser temperature of 30 °C yielded the highest first fuel yield of 70.7 wt%. When raising the temperature to 40 °C, the second fuel yield was up to 7.3 wt%. The results of the fuel properties analysis revealed that the first fuel had a high heating value (HHV) of 42.4 MJ/kg. There is a chemical composition of substances in the diesel fuel group mostly. But the first condenser temperature increased from 10 to 50 °C, causing a decrease in calorific value and density. This is a result of chemical compositions where many macromolecules are condensed in the fuel. For the analysis of the second fuel, it was found that the HHV was 38.1 MJ/kg, which was 4.3 MJ/kg lower than the HHV of the first fuel. However, the calorific value and density of the second fuel increases as the temperature of the first condenser increases. The chemical composition of the second fuels is Benzene, Toluene and Cyclononane as its main constituents, giving it a physical appearance like that of gasoline. But, in second fuels there is a chemical composition of Dicyclopentadiene. It has a clear yellow color and a pungent odor that annoys users. If in the future this substance can be eliminated, it will enable the production of fuel from plastic waste as a substitute for gasoline.

Effect of Diesterol blends on the noise vibration and harshness of a Genset engine

The present investigations deal with the combined effect of Diesterol blends (B20D75E5, B20D70E10, and B20D65E15) on the performance, combustion, noise, and vibration characteristics of a compression ignition Genset engine. Studies were carried out to make the fuel blend homogeneous and stable as ethanol is immiscible in diesel/biodiesel due to its chemical structure. It is found that the Diesterol blend becomes stable when biodiesel is used as a bonding agent between ethanol and diesel. However, the higher concentration of ethanol has stronger bonding, which resulted in poor stability. The stable blends were used to study the performance characteristics of the Genset engine. The results showed that the brake thermal efficiency increased by 10.4% by adding 5% ethanol in diesel–biodiesel compared to the 15% ethanol in diesel–biodiesel blends. The brake-specific fuel consumption was found to increase by 10% due to the decrease in calorific value with the addition of ethanol. The peak value of the in-cylinder pressure gradually increases up to 10% ethanol share and further addition in the fuel blend decreases the cylinder peak pressure, which may be due to a reduction in the lower calorific value of the blended fuel when compared to conventional diesel. The water content in the blends reduced the combustion activity and caused a slight increase in vibration due to the increased instant heat release rate in 10% and 15% ethanol share. The maximum vibration reduction was observed for the 5% ethanol blend by 1.83%. On the other hand, adding 15% ethanol decreased the engine noise by 2.7% compared to the 5% ethanol blend.

Effect of ternary fuel blends on performance and emission characteristics of single cylinder diesel engine

The higher alcohol such as hexanol was added at various concentrations with diesel in this current research work while retaining the neem biodiesel at 20% concentration to form the ternary fuel blend. In a single cylinder diesel engine, three distinct ternary blends (B20HB10, B20HB20, B20HB30) were taken and all the blends were tested and the results were contrasted with a binary blend (D80:B20, namely B20) and pure diesel fuel. The experiment showed that when the alcohol concentration rises from 10 % to 30 % because of the decrease in calorific value, the brake thermal efficiency decreases slightly. In addition, owing to the availability of intrinsic oxygen in it, all the ternary blend contributes to a decrease in HC and CO emissions, which leads to more complete combustion. It was also found that there was a substantial reduction in NOx emissions for all ternary blend due to the high latent heat of vaporization.

Paddy straw procurement challenges and its effect on cost of power generation

Attention towards the use of biomass for Power Generation has increased intensely from the past few years because of the awareness of global warming and a bad effect on the environment due to the fossil fuels combustion. This paper addresses the challenges for power production using paddy straw faced during the procurement and its storage. This paper opted an investigative study using the open-ended approach of grounded theory, including sample collection and experimenting. It has been observed that the various challenges are farmer awareness, transportation cost, storage cost, degradation due to storage and pre-feeding costs. The results have shown that there is 20.49% decrease in Calorific Value due to degradation of paddy straw at storage. The cost of generation in the month of procurement (Oct) is 0.02304$/kWh and it has been evident that increase is exponential in nature and stepped to 25. 76% in one year which is quite effective and make this study fit for its purpose.

Experimental investigation of imbert downdraft gasifier using rice straw briquettes

ABSTRACT The mechanized harvesting of rice crop has led to open-field burning of rice straw that liberates a large amount of greenhouse gases (GHGs), which have a negative effect on the environment. Gasification is an efficient technology for the conversion of biomass to producer gas with minimal greenhouse gas emissions. The present study was planned to convert the abundantly available rice straw into briquettes and its thermochemical conversion into producer gas for thermal energy utilization. The performance of imbert type gasifier was investigated using rice straw briquettes as fuel by studying the influence of airflow rate on fuel consumption rate and temperature profile inside the combustion zone. The augmentation of airflow rate from 0.0022 to 0.0042 m3/s led to a significant increase in feedstock consumption rate (63.3%). The time taken for boiling of water also increased with an increase in airflow rate which may be attributed to the corresponding decrease in calorific value of producer gas. Rice straw briquettes with cotton stalks as a binder (90:10) can act as a clean alternative fuel for gasification and the producer gas generated can be used for various thermal applications.

Physico-chemical and emission characterization of emulsified biodiesel/diesel blends

ABSTRACTBiodiesel/diesel blends (BDB) were prepared using different biodiesel percentages (10, 15 and 20% v/v) namely B10, B15 and B20, respectively. A high energy emulsification method was employed for this purpose. An engine test bed was utilized to combust the emulsion in order to investigate emission gas concentrations such as CO, NOx, CO2, O2 and smoke. The emission concentrations of NOx and O2 were decreased with increasing biodiesel concentration. However, the emission of CO2 was increased with the increasing amounts of water. The highest concentration of NOx was found for B15. The physicochemical properties of BDB emulsion fuel in terms of viscosity and calorific value were also measured and investigated. Furthermore, biodiesel showed the highest viscosity compared to diesel and BDB fuels. The viscosity of BDB fuels was increased from B10 to B20. The increasing biodiesel concentration showed a decrease in calorific value. Hence, emulsified biodiesel fuel is a promising alternative fuel for reducing harmful emissions.

Storage and Fuel Quality of Coniferous Wood Chips

Wood chips from Norway spruce (Picea abies L.) and silver fir (Abies alba L.) were stored for a period of 15 months (experimental pile was 4.0 m high). Atmospheric temperature and the temperature inside the pile at heights of 1, 2, and 3 m were measured in regular intervals. Samples were taken from an assortment of heights at the beginning and the end of the experimental period. Subsequently, the samples were subjected to an analysis of moisture content and other properties such as calorific value (according to the standard STN ISO 1928:2003 and ONORM M 7132) and ash content (according to the standard STN ISO 1171). The most significant decrease in the chips’ moisture content, and increase in the calorific value from the beginning of storage, was at the height of 1.0 m. An increase in the moisture content and decrease in calorific value was recorded for samples taken from the height of 3.0 m. Samples taken from this height showed an increase in ash content after a 15-month storage period. The experiment described the influence of specific weather conditions on the development of temperature, calorific value, and ash content of coniferous wood chip piles with particle size up to 35.5 mm.

Design of PID Filter Controller with Genetic Algorithm for Mimo System in Modern Power Generation

In this work, a new technique based on Genetic Algorithm for designing multivariable PID filter controller has been developed and applied to gasifier control of ALSTOM benchmark challenge II. The coal gasifier is the main component in Modern power generation. Coal gasifier involves several performance and robustness requirements in addition to actuator constraints under three operating loads (no-load, 50% and 100% load). The proposed GA optimises the tuning parameters of PID constants in terms of robustness and performance. The optimised controller meets all design objectives under all operating conditions. Robustness of the controller is tested for step and sinusoidal pressure disturbances applied at the inlet of throttle valve along with increase and decrease of calorific value of fuel fed-in (coal). Simulation results obtained confirmed the superiority of proposed technique for gasifier problems.

High Pressure Oxydesulphurisation of Coal—A Parametric Study

The current study is focused on controlling sulphur emissions by pre-treating coal to remove sulphur prior to combustion using the oxydesulphurisation technique. Three British coals were chosen for the study. Working with these coals gave a better insight to the oxydesulphurisation reactions for pyritic and organic sulphur. Effect of air and oxygen pressure in a fixed time interval on sulphur removal was studied by series of experimental runs at various temperatures. Heating value recoveries were significant. Increase in oxygen content is reported as a measure of carbon loss. The coal samples were analyzed according to British standard methods. Experimental results demonstrate that the sulphur removal was enhanced with the increase in air pressure, particularly up to 100 bars, with only a small decrease in calorific value at a particular temperature. Increasing temperature was witnessed to be more important in sulphur removal than increasing pressure.

Decrease of Calorific Value and Particle Size in Coal Stockpiles

During storage of excess amount of coal, they lose both their economical value and cause environmental problems. In this work, two industrial-sized stockpiles were constituted at a coal stockyard of Western Lignite Corporation (WLC) in Tuncbilek, Turkey. The size of the stockpiles, formed as triangle prisms, was about 10 m × 5 m wide with a height of 3 m; each mass being approximately 120 tons of coal in total. Some of the parameters that were effective on the stockpiles were measured in a continuous manner during this experimental work. The calorific losses and the decreases that occurred in particle size due to atmospheric conditions were also examined and detailed as the result of this work.

Studies on Storage and Use of Biomass Briquettes in Combustion and Gasification Reactor

Storage, combustion and gasification behavior of biomass briquettes made from groundnut shell powder (l180 -150 µm) and briquettes made of saw dust and castor deoiled cake were studied. It was found that storage of briquettes through the high humidity period did not create any problem. However, with the increase of storage duration, ash content increased, resulting into decrease in calorific value of biomass briquettes. Combustion and gasification studies revealed that 25 and 35 mm diameter briquettes could be satisfactorily gasified in open core and throat type down draft gasifier reactors, but up draft reactor was not found suitable for gasification on continuous basis.

Coal-quality deterioration in a coal stack of a power station

Coal's quality deterioration has been assessed by measuring its carbon and hydrogen contents, calorific value, hard groove grindability index, and reactivity by a differential-scanning calorimeter (DSC). The deterioration, was more prominent in sunny days with intermittent rain. Annually approximately 2500 kJ per kg decrease in calorific value of coal the was observed. Possible remedial measures have also been discussed.

Effects of Coal Oxidation on Calorific Value

A brief investigation of the effects of oxidation on the calorific values of three Turkish lignite samples has been made. The lignite samples have been vacuum dried and oxidized in pure oxygen at 35, 45, and 55 C at 100 kPa for 10 days. The calorific values of the oxidized and unoxidized samples have been measured. A relation has been observed between the extent of oxidation and decrease in calorific value. Various possibilities of modelling the relation have been explored.