Heating Value Of Fuel Research Articles

Effect of wet and dry torrefaction process on fuel properties of solid fuels derived from bamboo and Japanese cedar

Torrefaction is a promising pretreatment process to convert biomass into high energy density solid fuel for further thermal conversion systems. In this study, the effects of wet and dry torrefaction on the properties of solid fuels prepared from bamboo and Japanese cedar were investigated in a batch reactor. The yields of solid fuels decreased with increasing treatment temperature in both torrefaction processes, mainly due to the decomposition of cellulose and hemicellulose. Cellulose showed higher reactivity than hemicellulose in both biomasses. The higher heating values (HHV) of solid fuels prepared at the treatment temperatures higher than 240 °C in both torrefaction processes reached the same level as those of commercial coals. Wet torrefaction was better than dry torrefaction for decomposing bamboo and Japanese cedar. Dry torrefaction had more favorable impact than wet torrefaction on improving the fuel properties of bamboo and Japanese cedar because of its lower energy input, higher solid fuel yield, higher energy yield, and similar HHV under the same conditions. The crystalline structure of solid fuel had no great change below 260 °C in both torrefaction processes and was completely destroyed at 300 °C during dry torrefaction.

Estimation of biomass higher heating value (HHV) based on the proximate analysis by using iterative neural network-adapted partial least squares (INNPLS)

The higher heating value (HHV) of biomass fuels is a crucial factor in the techno-economic analysis and subsequent development of bioenergy projects. In this study, iterative neural network-adapted partial least squares (INNPLS) was applied to estimate the HHV of biomass fuels as a function of fixed carbon (FC), volatile matters (VM), and ash content. The ANN paradigm was used to correlate the inputs and the outputs of PLS score vectors thorough iterative training procedure. The prediction capability of the proposed model was compared with those of the classical PLS, the coupled principle component analysis and ANN paradigm (PCA-ANN), and the neural network-adapted partial least squares (NNPLS). The presented models were developed, trained, and tested using 350 data points obtained from the published literature. According to the results obtained, the INNPLS showed an excellent capability to model the HHV of biomass fuels over the other methods. This approach was then embedded into a simple and user-friendly software for estimating the HHV of biomass fuels on the basis of their proximate data. The developed software can be utilized for reliable and accurate estimation of biomass HHV based on only three input parameters as an alternative to the lengthy and costly laboratorial measurements.

Prediction of standard heat of combustion using two-step regression

Heat of combustion is a thermochemical property that is used for assessing the heating value of solid and liquid fuels as well as the calorific value of food and supplements. It is also used to identify fire hazards of hazardous materials. Heat of combustion has many applications across diverse areas including in jet fuel and propellant formulations, the disposal of combustible waste, the study of foods and supplements for humans and animals, as well as in ecological studies. This study proposes a simple and predictive model for predicting standard heat of combustion. This model was developed using a group contribution approach. The group contribution method represents chemicals according to 220 first-order and 130 second-order groups. The first-order groups are simple groups that describe a wide variety of chemicals, whereas the second-order groups describe polyfunctional compounds and are used to differentiate between isomers. In this study, 680 experimental data points comprising the standard heat of combustion for pure chemicals were collected from open literature. This data set represents various types of groups. The group contributions were regressed using linear regression in MATLAB, yielding an R2 value of 0.9993 with SD, AAE, and ARE values of 71.9892, 53.1008, and 4.6162. The proposed model was found to be predictive and capable of predicting the heat of combustion of various chemicals, which are not only limited to hydrocarbons but also include chemicals that contain groups of alcohol, ester, ether, amine, amide, aromatic, halogen, and sulfur.

Расчет теплоты сгорания древесного топлива по элементному составу

Расчет теплоты сгорания древесного топлива по элементному составу

Engine performance and emissions characteristics of a diesel engine fueled with diesel-biodiesel-bioethanol emulsions

In this research work, the experimental investigation of the effect of diesel-biodiesel-bioethanol emulsion fuels on combustion, performance and emission of a direct injection (DI) diesel engine are reported. Four kind of emulsion fuels were employed: B (diesel-80%, biodiesel-20% by volume), C (diesel-80%, biodiesel-15%, bioethanol-5%), D (diesel-80%, biodiesel-10%, bioethanol-10%) and E (diesel-80%, biodiesel-5%, bioethanol-15%) to compare its’ performance with the conventional diesel, A. These emulsion fuels were prepared by mechanical homogenizer machine with the help of Tween 80 (1% v/v) and Span 80 (0.5% v/v) as surfactants. The emulsion characteristics were determined by optical electron microscope, emulsification stability test, FTIR, and the physiochemical properties of the emulsion fuels which were all done by following ASTM test methods. The prepared emulsion fuels were then tested in diesel engine test bed to obtain engine performance and exhaust emissions. All the engine experiments were conducted with engine speeds varying from 1600 to 2400rpm. The results showed the heating value and density of the emulsion fuels decrease as the bioethanol content in the blend increases. The total heating value of the diesel-biodiesel-bioethanol fuels were averagely 21% higher than the total heating value of the pure biodiesel and slightly lower (2%) than diesel fuel. The engine power, torque and exhaust gas temperature were reduced when using emulsion fuels. The brake specific fuel consumption (BSFC) for the emulsion fuels were observed to be higher in comparison to diesel, A. The CO2 (carbon dioxide) and CO (carbon monoxide) emissions were reported to be lower than diesel oil. The effect of using emulsion fuels decreased the NOx (nitrogen oxides) emissions at medium engine speeds, i.e. approximately 30.0%. Lesser NOx emission was attributed by the reduction of cetane number of the diesel-biodiesel-bioethanol emulsion fuels’ cetane number as the amount of bioethanol increases. However, the emissions of NOx were found to increase gradually at low speed (∼1600rpm), high load; high speed (∼2400rpm), medium load conditions. It was found that the combustion performance and emissions of the diesel engine very much depend on the fuel, its emulsion combination types and engine operating conditions.

Techno-economic analysis and environmental impact assessment of a 10 MW biomass-based power plant in Malaysia

Considering that renewable energy is the primary energy source in the future, this study investigates biomass power for sustainable and secure energy supply. Biomass fuels in Malaysia include empty fruit bunch, mesocarp fiber, palm kernel shell, oil palm frond, oil palm trunk from palm oil plantation, and woody biomass from forests. The moisture content and heating value of palm oil-based biomass fuels are analyzed relative to their cost savings in a 10 MW biomass power plant. The net present value, internal rate of return, and payback period for various finance options and at various system efficiencies are also presented. Results indicate that for an empty fruit bunch priced at MYR 20/t without loan, the net present values are MYR 45.31 million, MYR 54.32 million, and MYR 57.74 million, with 20%, 30%, and 40% system efficiencies, respectively; the internal rates of returns are 21.88%, 22%, and 21.11%, respectively; and the payback periods are 4.16, 4.20, and 4.22 y, respectively. The 10 MW plant releases 50,130 t less CO2, 750 t less SO2, 218.65 t less NOx, and 22.83 t less CO emissions in the environment compared with the existing energy mix.

Analysis on using biomass lean syngas in micro gas turbines

The paper presents an analysis on small systems for converting biomass/wastes into power using Micro Gas Turbines (MGT) fed with gaseous bio-fuels produced by air- gasification. The MGT is designed for burning various fossil liquid and gas fuels, having catalogue data related to natural gas use. Fuel switch changes their performances. The present work is focused on adapting the MGT for burning alternative low quality gas fuel produced by biomass air gasification. The heating values of these gas fuels are 3 to 5 times lower than the methane ones, leading to different air demand for the stoichiometric burning. Validated numerical computation procedures were used to model the MGT thermodynamic process. Our purpose was to analyze the influence of fuel change on thermodynamic cycle performances.

Modification of Dulong's formula to estimate heating value of gas, liquid and solid fuels

Estimation equations for determining the heating value of hydrocarbon fuels were evaluated. Several types of estimation equations were proposed so far to determine the heating value on the basis of the elemental composition. The estimation equations were used to evaluate the elemental composition and the heating value of 406 standard gaseous organic compounds. As a result of the evaluation, Dulong's formula was appropriate for estimating the heating value; however, only a limited range of heating values can be determined, because Dulong's formula was developed for determining heating value of coals, which have unidentified structures. Another reason for the limitation was that the effect of latent heat. Therefore, Dulong's formula were modified with the lower heating values (LHV) of 406 standard gaseous organic compounds, which have identified structures, to obtain the following modified formula taking latent heat into account:

Heating value of biodiesel: An empirical and theoretical exploration

ABSTRACTThe heating value of a fuel affects both the brake thermal efficiency and combustion characteristics of an engine. Its value for fuel blend cannot be calculated based on the blend ratio even though the heating values of blend fuels are known. Therefore, a relationship was formulated from the experimental data to predict the heating values of fuel blends. This study was carried out to compute the theoretical heating values of raw as well as purified pungamia oil with different blend ratio by means of SPSS software (ver. 16). The Durbin–Watson (multiple regressions) tests were carried out in the present study to validate the experimental results. The values of density, flash point, viscosity, and percentage of blends were considered an independent variable, and the heating value was considered a dependent variable for the analysis of heating values of different pungamia oil blends with diesel. The theoretically calculated heating values and relationship between the independent variables were around ± 1%. Also, these values were compared with that of the experimental results of other researchers and the variation was only about 2%. Thus, the validations of developed relation with experimental results show good compliance.

An artificial intelligence approach to predict gross heating value of lignocellulosic fuels

The gross heating value (GHV) is one of the most significant properties of biomass fuels in designing and operating any fuel processing systems. This study deals with a new method to calculate the GHV from the proximate analysis of different kinds of lignocellulosic fuels by using Levenberg–Marquardt trained artificial neural network (ANN) as an artificial intelligence method. Furthermore, a new nonlinear regression model was developed for this study. The published correlations were employed with the various biomasses to obtain a comparison with the ANN model and developed nonlinear correlation in this study. The results indicate that the artificial intelligence approach offers a high degree of correlation and its robustness and capability to compute GHV of any lignocellulosic fuels from its proximate analysis. Therefore, the proposed artificial intelligence is highly promising tool to use in designing and operating of any thermolysis process for lignocellulosic fuels.

Use of Biomass and Waste for Energy Purposes

This article focuses on the use of alternative renewable energy sources (waste and biomass) as a full replacement for traditional non-renewable resources. We focus on ways to increase the heating value of the raw materials by drying and pyrolysis, and the possibilities of influencing low heating value of fuels by using pyrolysis products. Pyrolysis generates heat and products, which may be used directly as fuel or after modification as additives for fuels. Pyrolysis is a suitable process for recovery of municipal, biological or contaminated waste. It contributes to a sustainable way of energy production and waste management. Moreover, the production in local conditions from local resources, increases land use, employment in the regions and energy self-sufficiency in the state. With combined production of fuels (pellets, briquettes) from biomass, wastes and pyrolysis products we expect to increase the heating value of well over 20 MJ.kg-1.

Modeling and Assessment of a Biomass Gasification Integrated System for Multigeneration Purpose

The use of biomass due to the reduction in greenhouse gas emissions and environmental impacts has attracted many researchers’ attention in the recent years. Access to an energy conversion system which is able to have the optimum performance for applying valuable low heating value fuels has been considered by many practitioners and scholars. This paper focuses on the accurate modeling of biomass gasification process and the optimal design of a multigeneration system (heating, cooling, electrical power, and hydrogen as energy carrier) to take the advantage of this clean energy. In the process of gasification modeling, a thermodynamic equilibrium model based on Gibbs energy minimization is used. Also, in the present study, a detailed parametric analysis of multigeneration system for undersigning the behavior of objective functions with changing design parameters and obtaining the optimal design parameters of the system is done as well. The results show that with exergy efficiency as an objective function this parameter can increase from 19.6% in base case to 21.89% in the optimized case. Also, for the total cost rate of system as an objective function it can decrease from 154.4 $/h to 145.1 $/h.

Solar molten salt heated membrane reformer for natural gas upgrading and hydrogen generation: A CFD model

Parabolic trough solar collectors can be used to drive endothermic reactions, such as methane reforming, while using molten salts as a heat transfer fluid. However, linear focus concentrators can only provide temperatures under 600°C, resulting in CH4 conversions well below 50%. The equilibrium can be shifted toward much higher conversions if H2 is continuously removed from the reaction mixture via a H2-selective membrane, while simultaneously generating a high-purity H2 stream. In this study, a tube-and-shell, molten salt-heated packed bed membrane reformer (Ni/Al2O3 catalyst, 5μm supported Pd film membrane) is analyzed numerically using computational fluid dynamics and non-isothermal formulation. The effects of molten salt supply rate and reforming feed flow rate on the reformer performance, which is evaluated in terms of CH4 conversion, H2 recovery, and selectivity to CO, are investigated. Depending on operating parameters, significant temperature and concentration gradients may form in both axial and radial directions. These gradients can be prevented by adjusting feed rates in the reforming and molten salt compartments. For the optimized case, CH4 conversion of 99% and H2 recovery of 87% are predicted for the molten salt feed temperature of 600°C and reforming feed space velocity of 5000h−1, which corresponds to a power density of 1.9kW/L and a fuel heating value upgrade of 40%. A preliminary techno-economic evaluation is provided.

천연가스 개조 승용차에 대한 실험적 연구(1) - 연비, 배기 및 주행 성능

In this study, the roadability, fuel economy and emission characteristics were evaluated for a natural gas converted vehicle. The results are as follows; Not only the shortage of power was observed in stall test, but also large deterioration of acceleration performance was exposed in roadability. Compared to the original LPG system, the acceleration is 76% in start acceleration and 45 ~ 65% in overtaking acceleration, especially the decline became larger when air conditioner is at work. Furthermore, because the mapping data, which controls the injection depending on driving condition, do not match up with injection system, the failure of air-fuel ratio feedback control occurs resulting from the large gap between the required and the really supplied amount of fuel. This failure cause the exhaust gas to emit without catalytic conversion and the fuel economy based on the fuel heat value to get worse 22% in the mode test and 16% in road test respectively. In addition, the existing injection system does not secure enough fuel at the starting so that it may lead to the fail of clod start, the deterioration of hot start and inharmonic of engine at the idle after start.

Development of a 100 kW plasma torch for plasma assisted combustion of low heating value fuels

Most thermal power plants need an auxiliary power source to (i) heat-up the boiler during start up phases before reaching autonomy power and (ii) sustain combustion at low load. This supplementary power is commonly provided with high LHV fossil fuel burners which increases operational expenses and disables the use of anti-pollutant filters. A Promising alternative is under development and consists in high temperature plasma assisted AC electro-burners. In this paper, the development of a new 100 kW three phase plasma torch with graphite electrodes is detailed. This plasma torch is working at atmospheric pressure with air as plasma gas and has three-phase power supply and working at 680 Hz. The nominal air flow rate is 60 Nm3.h−1 and the outlet gas temperature is above 2 500 K. At the beginning, graphite electrodes erosion by oxidizing medium was studied and controlling parameters were identified through parametric set of experiments and tuned for optimal electrodes life time. Then, a new 3-phase plasma torch design was modelled and simulated on ANSYS platform. The characteristics of the plasma flow and its interaction with the environing elements of the torch are detailed hereafter.

Experimental investigation of submerged flame in packed bed porous media burner fueled by low heating value producer gas

Combustion inefficiencies and high pollutants emissions keep motivating researchers to enhance combustion technology. Producer gas fuel from biomass gasification with its low heating value and high CO content requires a special combustor design for efficient burning. Porous media burner (PMB) has been widely investigated and proven to be well suited for low heating value fuels lean combustion. This study aims at performance investigation of PMB fueled by producer gas from biomass gasification. A downdraft gasifier system along with a PMB burner and heat recovery unit has been developed. The PMB comprises two layers of 10mm and 20mm diameter upper and lower alumina spheres packed, respectively. With PG heating value of about 5MJ/m3, lean to ultra lean stable combustion was achieved with equivalence ratios (Φ) in the range of 0.33<Φ<0.71. Combustion layer temperature was in the range of 1300–1550K. The lowest recorded emissions from the PMB were 6ppm and 230ppm for CO and NOx respectively. The heat recovered from the burner was utilized in hot air production of 7kWth that can be used for drying process in small industries. Maximum heat recovery heat exchanger effectiveness was about 93% with overall system efficiency of 54%.

Experimental Research on Low-Temperature Methane Steam Reforming Technology in a Chemically Recuperated Gas Turbine

Under the operating parameters of a chemically recuperated gas turbine (CRGT), the low-temperature methane steam reforming test bench is designed and built; systematic experimental studies about fuel steam reforming are conducted. Four different reforming forms are employed, including catalyst-only reforming, plasma-only reforming, piecewise synergistic reforming, and parallel synergistic reforming. A better reforming form for CRGT was determined by analyzing the effect of methane space velocity, steam-to-carbon ratio of fuel reforming (S/C), wall temperature, and plasma input power. All of the above factors had an effect on the reforming performance, but a direct and significant effect separately on effective carbon recovery rate, total enthalpy increasing rate, methane conversion, and fuel heating value increasing rate. The effective carbon recovery rate was taken as the chief indicator for choosing the right operating conditions, determining a best methane space velocity of 680 mL/(gcat·h). With the increase of S/C, total enthalpy increasing rate had a significant improvement; wall temperature had a positive effect on reforming, especially in synergistic catalysis. The effect of input power was linked with wall temperature in parallel synergistic reforming, with a greater effect at a higher temperature. Combining the experimental results with the theory analysis, parallel synergistic reforming is best, with a methane conversion of 51.23% and total enthalpy increasing rate of 25.73% at a wall temperature of 500 °C, an input power of 84.53 W, and an S/C value of 2.

Experimental Investigations of Spark Ignition in a Model Combustor With Synthesis Gas

The components of syngas derived from coal, biomass, and waste are significantly different from those of typical gas turbine fuels, such as natural gas and fuel oils. The variations of hydrogen and inert gases can modify both the fluid and the combustion dynamics in the combustor. In particular, the characteristics of spark ignition can be profoundly affected. To understand the correlation between the varying fuel components and the reliability of ignition, a test system for spark ignition was established. The model combustor with a partial-premixed swirl burner was employed. The blending fuel with five components, hydrogen, carbon monoxide, methane, carbon dioxide and nitrogen, was used to model the synthesis gas used in industry. The ignition energy and the number of sparks leading to successful ignition were recorded. By varying the fuel components, the synthesis gases altered from medium to lower heat value fuels. The ignition time, ignition limit, and subsequent flame developments with variations of air mass flow rates and fuel components were systematically investigated. With the increase of airflow, the syngas with a lower hydrogen content has a shorter ignition time compared with higher hydrogen syngas in the lean condition, whereas in the rich condition, syngas with a higher hydrogen content has a shorter ignition time. The effects of the hydrogen content, inlet air Reynolds number and spark energy on the ignition limit were investigated. The ignition limit was enlarged with the increase in the hydrogen content and the spark energy. Meanwhile, three distinct flame patterns after ignition were investigated. Finally, a map for the characteristics of the ignition and subsequent flame development was obtained. The results are expected to provide valuable information for the design and operation of stable syngas combustion systems and also provide experimental data for the validations of theoretical modeling and numerical computations.

Performance Evaluation of a Small-Scale Turbojet Engine Running on Palm Oil Biodiesel Blends

The experimental and simulated performance of an Armfield CM4 turbojet engine was investigated for palm oil methyl ester biodiesel (PME) and its blends with conventional Jet A-1 fuel. The volumetric blends of PME with Jet A-1 are 20, 50, 70, and 100% (B20, B50, B70, and B100). Fuel heating values (FHV) of each fuel mixture were obtained by calorimetric analysis. The experimental tests included performance tests for Jet A-1 and B20, while the performances of B50 to B100 were simulated using GasTurb 11 analytical software. In terms of maximum measured thrust, Jet A-1 yielded the highest value of 216 N, decreasing by 0.77%, 4%, 8%, and 12% with B20, B50, B70, and B100. It was found that B20 produced comparable results compared to the benchmark Jet A-1 tests, particularly with thrust and thermal efficiency. Slight performance penalties occurred due to the lower energy content of the biodiesel blends. The efficiency of the combustor improved with the addition of biodiesel while the other component efficiencies remained collectively consistent. This research shows that, at least for larger gas turbines, PME is suitable for use as an additive to Jet A-1 within 50% blends.

Uncertainties due to Fuel Heating Value and Burner Efficiency on Performance Functions of Turbofan Engines Using Monte Carlo Simulation

In this paper, the impacts of the uncertainty of fuel heating value as well as the burner efficiency on performance functions of a turbofan engine are studied. The mean value and variance curves for thrust, thrust specific fuel consumption as well as propulsive, thermal and overall efficiencies are drawn and analyzed, considering the aforementioned uncertainties based on various Mach numbers at a number of flying altitudes in order to yield a more accurate prediction of values of performance functions. The results of this study can be of essential significance for an optimal and robust design of turbofan engines. This study is done employing Monte Carlo Simulation method which is a probabilistic analysis method.