Net Calorific Value Research Articles

Water/Heavy Fuel Oil Emulsion Production, Characterization and Combustion

In order to produce a water/heavy fuel oil emulsion (W/HFO) with different water contents to cover the daily needs of a fire tube boiler or a water tube boiler, a special homogenizer is designed, constructed and tested. The produced emulsion is characterized and compared with the pure HFO properties. It is found experimentally in fire tube boiler that, the use of W/HFO emulsion with 8% of water content (W0.08/HFO0.92) instead of HFO leads to a saving rate of 13.56% in HFO. For explaining the obtained energy saving the term “equivalent heat value (EHV) of the W/HFO emulsions”, defined as the ratio of the W/HFO emulsion net calorific value to the HFO content in the emulsion, is used. Based on direct measurements, provided in this work, it was found that the equivalent heat value (EHV) increases with the water content in the water/heavy fuel oil (W/HFO). It reaches 1.06 times of HFO net calorific value at water content of 22.24%. The obtained, in the present work, experimental results demonstrate the dependence of the emulsion EHV on its water content. These results are in agreement with the results of other authors. Therefore, the contribution of water droplets in the emulsion combustion is verified. It is found experimentally that, the emitted CO, SO2 and H2S gases from the fire tube boiler chimney decreases by 5.66%. 3.99% and 48.77% respectively in the case of (W0.08/HFO0.92) emulsion use instead of HFO.

Textural properties and organic matter in sediments from a hard coal mine landfill

Textural properties as micropore surfaces and sorption capacity, chemical and technological analyses of sediments collected in the Lazy coal mine landfill (Upper Silesian Coal basin) are presented. The adsorption capacities together with net calorific values (Qid) and total organic carbon (TOC) decreased in the direction of flow while the ash content (Ad) increased. The samples with the highest TOC content have a relatively beneficial Qid and for residual coal particles from coal mining, were comparable with the Qid values of brown coal. The sorption capacity increased with increasing micropore content and correlated with higher levels of TOC. The sorption capacity decreased with distance from the saline water input. These materials play a significant role in the self-cleaning of mine water in-situ.

Near infrared technique as a tool for the rapid assessment of waste wood quality for energy applications

Considering the focus of the current European policy in promoting the reuse of waste products and increasing the share of renewable energies, waste wood is becoming an appealing resource rather than a product to dispose of. End-life waste wood products could be used for the production of panel board or as feedstock in combustion units. In this study, waste wood samples have been collected in a big panel board company, and have been analyzed by means of Near Infrared Spectroscopy. Principal Component Analysis has been used in order to investigate the variability of the material, and Partial-Least Squares regression models have been developed for the prediction of moisture content and net calorific value. The results indicate that both models could be used in quality control applications, and Near Infrared Spectroscopy can be considered as a tool for the rapid evaluation of waste wood parameters for energy applications. Considering the high correlation between the two parameters it is also possible to analyze only the moisture content and have indications about the net calorific value using a simple linear regression, with positive effects in terms of quality control and the reuse of the waste wood material.

Briquetting of Dry Sugarcane Leaves by Using Press Mud, Cow Dung, and Buffalo Dung as Binders

The world’s population is increasing rapidly. This means that energy consumption and demand for energy are also increasing at the same rate. It is estimated that energy will need to be provided to 9 to 10 billion people by 2040. India is a leading consumer of energy in the world. In particular, it consumes a large amount of oil and natural gas to fulfil its energy demand. Due to uncertainty in the supply of oil and natural gas and their prices as well as environmental pollution, there is a need to shift towards other energy sources. Biomass is one of the first energy sources with specific properties and abundant availability. Today, 10% to 14% of the world’s energy supply is provided by biomass sources. Using agricultural waste (biomass) to make briquettes to generate power can be an alternative solution to the problems related to their disposal and pollution. The present work investigates the optimum ratio of dry sugarcane leaves to binders and optimum load and selects the best binder (cow dung, buffalo dung, and press mud) for making high-quality briquettes. The physical parameters and proximate analysis of the dry sugarcane leaf briquettes with the cow dung, buffalo dung, and press mud binders are investigated. The dry sugarcane leaf briquettes with the cow dung binder have the highest gross calorific value, net calorific value, split tensile strength, tumbling resistance, shatter resistance, and energy density ratio (16262.31 kJ/kg, 15362.1 kJ/kg, 7.164 kN/m2, 87.84%, 12.75%, and 0.9296, respectively). The estimated results show that cow dung is a better binder for making high-quality dry sugarcane leaf briquettes than the buffalo dung and press mud binders.

Fuel quality and dry matter losses of stored wood chips - Influence of cover material

Irregular seasonal demand from heat- and combined heat and power plants means that outdoor storage of forest fuels is an inevitable step in the forest fuel supply chain. Storage of fresh comminuted biomass render substantial dry matter and energy losses. Covering can protect wood chips from rewetting, leading to a higher net calorific value and lower dry matter losses, and thus increase the amount of available energy. This study examined the combined effect of covering material on fuel quality and the amount available energy from wood chips stored in a full-scale pile. The combined changes in fuel quality and dry matter loss reduced the amount of accessible energy by 9.8% in the uncovered part, by 5.6% when covered with water proof or light semi-permeable cover materials and by 1.0% when covered with a thicker semi permeable material. Fuel quality of wood chips can be improved by covering the piles during storage but the gain is affected by the type of cover material. Seasonal storage in properly covered chip piles facilitate an increased annual utilisation of chippers and chip trucks which reduces overall biomass supply chain cost.

Energy properties of bamboo biomass and mate co-products

Fossil fuels are being replaced by clean energy sources. Lignocellulosic biomass is considered an eco-friendly alternative, as it is a renewable raw material with high energy potential. In this context, the aim of this study was to determine the biomass energy properties of three bamboo species and mate. Thus, three species of bamboo (Bambusa vulgaris Var. Vittata, Dendrocalamus asper and Phyllostachys aurea) and Ilex paraguariensis co-products (branches and sticks) were performed. The particle size, basic density, moisture content volatiles content, ashes content, fix carbon, gross and net calorific value and energy density of these biomasses were evaluated. The biomasses analyzed here were considered suitable for energy purposes, in general, these presented volatile content between 75 and 85 %, fixed carbon content between 15 and 25% and ash content close to 1%. Average fix carbon content of all analyzed biomass was 16.13%. Ash content of Phyllostachys aurea, branches of Ilex paraguariensis and Dendrocalamus asper presented lower values, average of 1.63%. Bambusa vulgaris and Ilex paraguariensis sticks presented higher values, average of 2.65%. Phyllostachys aurea presented gross calorific value higher than, average of 19.35 MJ kg− 1. Bambusa vulgaris, Dendrocalamus asper, Ilex paraguariensis branches and sticks presented statistically equal values. Bambusa vulgaris, Dendrocalamus asper, Phyllostachys aurea showed net calorific value higher to the other analyzed materials and did not present statistical difference. Basic energy density of Phyllostachys aurea was higher to bamboo species. Ilex paraguariensis showed the lowest values with no statistical difference for branches and sticks.Article highlightsKnowledge of biomass properties enables the use of residues in bioenergy production as an eco-friendly alternative.Bamboo and Mate co-products have desirable characteristics and potential to produce bioenergy.The energetic performance of bamboo biomass was superior when compared to the branches and sticks of Ilex paraguariensis.

Impact of Roadside Drying on Delivered Costs for Eucalyptus globulus Logging Residue and Whole Trees Supplying a Hypothetical Energy Plant in Western Australia Using a Linear-Programming Model

Australia’s large potential forest bioenergy resource is considerably underutilised, due largely to its high delivered costs. Drying forest biomass at the roadside can potentially reduce its delivered cost through weight reduction and increased net calorific value. There has been little research on the impact of roadside drying for Australian conditions and plantation species. This study compared delivered costs for three forest biomass types—Eucalyptus globulus plantation whole trees and logging residue (LR)-disaggregated (LR conventional) or aggregated (LR fuel-adapted)—and three roadside storage scenarios—no storage, ≤two-month storage and optimal storage—to supply a hypothetical thermal power plant in south-west Western Australia. The study was performed using a tactical linear programming tool (MCPlan). Roadside storage reduced delivered costs, with optimal storage (storage for up to 14 months) producing the lowest costs. Delivered costs were inversely related to forest biomass spatial density due to transport cost reductions. Whole trees, which had the highest spatial density, stored under the optimal storage scenario had the lowest delivered costs (AUD 7.89/MWh) while LR conventional, with the lowest spatial density, had the highest delivered costs when delivered without storage (AUD 15.51/MWh). For both LR types, two-month storage achieved ~60% of the savings from the optimal storage scenario but only 23% of the savings for whole trees. The findings suggested that roadside drying and high forest biomass spatial density are critical to reducing forest biomass delivered costs.

Application of Hydrothermal Carbonization to Improve the Energy Properties of Peat

The influence of the process conditions of hydrothermal carbonization (temperature, process duration, the presence of a catalyst (citric acid), and the raw material/water ratio) on the properties of hydrochar obtained from peat was studied. The following regularities were found: the weight and energy yields of the hydrochar decreased with the temperature and reaction time. An increase in the reaction temperature from 170 to 230°С contributed to an increase in the calorific value (from 23.86 to 26.8 MJ/kg for the gross calorific value and from 22.26 to 25.02 MJ/kg for the net calorific value). An increase in the reaction time from 1 to 6 h also led to an increase in the calorific value (from 22.72 to 24.61 MJ/kg for the gross calorific value and from 24.61 to 23.20 MJ/kg for the net calorific value). The addition of a catalyst increased the gross and net calorific values of hydrochar by 6 and 6.2%, respectively.

Use of modelling to compare the impact of roadside drying of Pinus radiata D.Don logs and logging residues on delivered costs using high capacity trucks in Australia

Forest biofuel delivered costs are generally uncompetitive with fossil fuels. Drying forest biofuel can potentially reduce delivered costs through weight reductions and net calorific value increases.The study examined the impact of roadside drying (RD) and use of high-volumetric capacity trucks on delivered costs of Pinus radiata pulp-logs and logging residue (LR) chips supplying a gasification plant. Five truck configurations: 6-axle semi-trailers; 9-axle B-doubles; proposed high-volumetric (HV) capacity versions of these trucks (HV semi-trailers and B-doubles); and 11-axle pocket road trains (PRT), were investigated across six supply areas using a forest biomass supply chain tool.Without RD all truck configurations were weight limited transporting logs, and all (except HV semi-trailers and B-doubles) were volume limited transporting LR chips. Post-RD all truck configurations were volume limited transporting logs or LR chips, (except HV B-doubles transporting logs).RD considerably reduced delivered costs: PRT (22%), B-doubles (24%), semi-trailers (25%) for logs and PRT (28%), B-doubles (29%), semi-trailers (30%) for LR chips. Delivered cost differences between truck configurations reflected transport cost differences.Without RD, truck trips transporting log were directly related to truck weight capacity. Additional volumetric capacity enabled HV semi-trailers and B-doubles to transport 6% and 4% more LR chips than standard versions, respectively, with equivalent truck trip reductions. RD weight reductions were: logs (33%); LR chips (53%), with consequent reductions in truck trips. PRTs required fewest truck trips to transport logs and LR chips without RD and the second fewest for logs post-RD due to their high weight and volumetric capacities.

Development of models for the prediction of energy content of fresh municipal solid waste from an unsecured landfill in India.

The enormous quantities of municipal solid waste (MSW) generation in Indian cities has emerged as a serious concern. In order to reduce the negative environmental impacts of MSW accumulation in dumpsites or unsecured landfills across India, various measures have been proposed to facilitate conversion of MSW into a valuable resource. One such measure is the immense potential for utilization of MSW as a source of energy. In this study, a comprehensive estimation of the energy potential of freshly dumped MSW has been conducted at a large unsecured landfill site in Okhla, Delhi, which is the capital city of India. Multiple regression models were developed to predict gross calorific value (GCV) and net calorific value (NCV) of MSW in terms of physical composition, proximate analysis and ultimate analysis of the waste. The developed models were found to give a reasonably good prediction of energy content of freshly dumped MSW in the landfill. Food waste, inerts, textile and paper were found to be the prime constituents of fresh MSW arriving at the landfill site. Based on the statistical analysis, volatile matter content and oxygen content of MSW were found to be non-significant terms in the energy content models derived using proximate analysis and ultimate analysis, respectively. The models developed in this study can be used to predict energy content of MSW at other landfill sites in India under similar climatic conditions and disposal practices.

Biomass Energy Potential for Domestic Combustion in Myanmar: Characterization of Biomass Fuel Pellets

Biomass is the largest contributing energy source in Myanmar due to low cost and environmental consequences. Myanmar annually produces 5.77 million ton of rice husk on 26.21 million ton of paddy rice production and 114,975 cubic ton of wood left in the forest on annually 365,000 ton of wood logs. Myanmar still needs more energy consumption to develop the agricultural economy and biomass energy in the future of the country although electricity supply is expected to increase to 55 percent in 2021-2022 FY. In this work, the chemical composition and energy composition of rice husk and assorted wood were determined. And then, the physicomechanical properties of rice husk pellets without doing size reduction but assorted wood pellets with size reduction were analyzed and compared these results with ISO 17225-6 and ISO 17225-2 standards. The assorted wood lignin content was higher than of rice husk. The ash content of rice husk was higher than that of assorted wood due to large amount of ash forming compounds such as silicon dioxide and potassium oxide in rice husk. The bulk density, net calorific value, and mechanical durability of assorted wood pellets were higher than that of rice husk pellets due to the larger amount of lignin in assorted wood. The physicomechanical properties of produced pellets were complied with ISO standards.

Characterization of dry fractions contained in municipal solid waste in developing countries: a case study of a region in Morocco

Despite its impact on the environment, the most widely used method for waste management in African countries is landfilling. Energy recovery, in particular refuse derived fuels (RDF), can be a promising option for sustainable waste management in the context of Africa. The scope of this work is to characterize dry fractions contained in municipal solid waste produced in a province in Morocco. The characterization was done according to the seasons, and to the type of area (urban and rural). A second characterization was done in laboratory for dry fractions in study area, and five other refuse derived fuel formulated. The results show that combustible fractions constitute 30% of the waste produced in the study area with a high quantity of textile and hygienic waste. Thus, the seasons and the type of area have an impact on the distribution of some combustible fractions such as paper, textiles, and hygienic waste and wood. Laboratory analysis of dry fractions from the study area and the combinations formed shows the effect of the composition on the quality of RDF, the presence of plastic improves its calorific value. The NCV, ash content, and chlorine content of dry fractions in the study area were measured obtaining a value of 18.65 MJ kg−1, 6.48%, and 0.21%, respectively. Therefore, the most predictive empirical model of net calorific value is the Chang model.

Energy Potential of Agri Residual Biomass in Southeast Asia with the Focus on Vietnam

Southeast Asia currently faces a huge increase in energy consumption and serious environmental issues. A widely underutilized and still unexplored potential of these countries lies in residual biomass. In the present research, the production quantities and energy yields of the most abundant agricultural byproducts in Vietnam, i.e., rice straw, rice husks, sugarcane bagasse and sugarcane trash, were calculated. Total crop yield, residues ratio and net calorific values of the wet basis biomass served as input parameters for the calculations. Moreover, the results were found for individual regions and provinces of the country. The findings show that the production of paddy rice straw is an enormous 97 million tons per year with an energy potential of over 380 TWh, as well as another 9 million tons yearly and 35 TWh in the case of rice husks. More than half of rice biomass production is concentrated in the Mekong River Delta region. Harvesting and processing of sugarcane annually generates about 5 million tons of bagasse and over 3.5 million tons of sugarcane trash with the total energy potential of about 27 TWh, which is primarily available in the central regions of Vietnam. The detailed laboratory determination of fuel-energy properties of studied materials, such as gross and net calorific value, volatile matter, ash and moisture content and contents of chemical elements was also carried out. Based on the research results and literature analysis, the possibilities of biofuel production and energy utilization of the above-mentioned residues are discussed.

Fuel and material utilization of a waste shiitake (Lentinula edodes) mushroom bed derived from hardwood chips I: characteristics of calorific value in terms of elemental composition and ash content

To understand the fuel characteristics of a waste shiitake mushroom bed derived from hardwood chips, the moisture content at the time of disposal and after 1 month, as well as its calorific value, ash content, and elemental composition, were investigated. The moisture content on a wet basis (MCw) was 78% at the time of disposal and was as high as 63% even 1 month after disposal. It is considered that the slow drying process is caused by the low moisture permeability of the skin of mushroom bed, and therefore, it is preferable to crush the waste mushroom bed before drying. Comparing the gross calorific value on a dry basis of the waste mushroom bed with that of the cultivation bed wood chips, the value inside of the waste mushroom bed was similar, while that of its skin was significantly lower (by 11%). The reason for this lies in the significantly higher ash content and nitrogen content compared to those of wood. When analyzed from the combustion heat of the contained elements, it was found that both the cultivation bed wood chips and the waste mushroom bed had almost no hydrogen contributing to combustion due to their high oxygen content, and they were dependent on the heat generation of carbon. As a result of finding the relationship between the net calorific value that can be used as a boiler fuel and MCw, for example, the value at an MCw of 50% was calculated to be 7.6 MJ/kg, which was almost the same as that of sugi (Cryptomeria Japonica) sapwood and bark. The ash content of the waste mushroom bed was about 7%, which is close to that of bark and about ten times that of the wood used for the cultivation bed. When the waste mushroom bed is used as boiler fuel, appropriate ash treatment is required as in the case of using bark.

Impacts of changes in commercial non-coking coal grading system and other coal policies towards estimation of CO2 emission in Indian power sector

In India, coal-based electricity is a leading cause for greenhouse gas emissions. However, many uncertainties prevail in the emissions estimation from coal-fired plants due to the dynamics of varying net calorific values (NCV) and carbon emission factors (CEF) associated with different grades of coal coupled with the coal oxidation factors (COF) of power plants. After 2012, a major change in the Indian non-coking coal grading system along with other developments like (a) rising efficiencies of thermal power plants, (b) changes in coal quality due to mining at deeper seams, (c) coal mining and distribution strategy have affected the NCVs, CEFs and COF associated with coal combustion in Indian power plants. These changes are expected to impact the CO2 emissions from coal-based power plants. Our findings suggest that implementation of the newly revised, power sector specific, NCV-CEF-COF-2015 have resulted in reduction of CO2 emission estimates from coal-based electricity generation by about 139 Tera grams (Tg) (12%) and 73 Tg (7%) for the year 2015 as compared to the corresponding emissions calculated using NCV-CEF-COF-1994 and NCV-CEF-COF-2007, respectively. Going forward, these newly estimated factors will provide greater accuracy in emissions estimation from coal-fired power plants in India.

ANALYSIS OF CALORIMETRIC METHOD OF MEASUREMENT OF NATURAL GAS CALORIFIC VALUE

The article considers the current methods of measuring the calorific value of natural gas which are valid in the upto-date gasometry. The procedure for measuring the gross and net volume-basis specific calorific value of natural gas by the calorimetric method is analyzed. It is shown that to increase the accuracy and validity of measurement results, the experiment to determine the values of gross and net volume-basis specific calorific should be performed for at least 5 samples of the investigated gas. A methodology for estimating the accuracy of measuring the gross and net volume-basis specific calorific values of natural gas by the calorimetric method by finding estimates of the uncertainty of the obtained measurement results taking into account both random and systematic influencing factors are developed. The uncertainty budgets for measuring the gross and net volumebasis-specific calorific values of natural gas have been developed for the practical implementation of the methodology. The results of experimental studies of samples of one of the natural gas fields are given and the objective values of the gross and net volumebasis specific calorific with estimates of extended uncertainty are obtained.

Uticaj temperature pirolize na stepen odsumporavanja uglja nižeg ranga sa visokim sadržajem organskog sumpora

The sulfur in coal not only influences the coke quality but also pollutes the environment during the combustion. The desulfurization of high organic sulfur coal is a key issue in coal cleaning science. As the pyrolysis has been used in low-rank coal conversion to obtain gas/liquid products and coal char, the desulfurization effects of pyrolysis on the low-rank coal with high organic sulfur requires further studies. This study investigated the desulfurization performance of high organic sulfur low-rank coal by the pyrolysis and the changes in the coal calorific value and sulfur forms during the pyrolysis. The XPS was applied to analyze the changing regulation of sulfur that forms on coal surface. The results indicated certain amount of FeS was newly created during the pyrolysis and high amounts of sulfate sulfur was transferred to pyrite sulfur and formed more FeS2 when compared to the distribution of raw coal. The total sulfur content of coal was reduced from 2.32% for raw coal to 1.68% for 700 °C pyrolysis coal and then the pyrolysis temperature had little effect on the sulfur content. The net calorific value (at constant volume and air-dry basis) was increased from 17.38 kJ for raw coal to 24.35 kJ for 700 °C pyrolysis coal. The pyrolysis temperature of 700 °C may be the best pyrolysis temperature for both low sulfur content and high calorific value.

Operation Indicators of Diesel Locomotive Engines Using Natural Gas

The theoretical model of main performance indicators of diesel locomotive engines using natural gas is exposed. According to the model, the heat released during the combustion of mixed fuel can be determined. The composition of natural gas, which is indicated in the passport when refueling a diesel locomotive, is taken into account. Thus, it became possible to adjust the program of regulating the fuel supply control system according to the operating modes of a diesel locomotive engine by introducing a composition coefficient. The results of analyzing the variation range in the net calorific value of gas during the conversion of diesel locomotives for using the natural gas as a motor fuel are presented. As exposed, the variation range in the net calorific value at various examined fields varies up to 32.4%. The so-called net calorific value of diesel fuel and natural gas combustion is suggested to be considered for operating diesel locomotive engines with liquid gas fuel, in addition to atmospheric conditions.

ВПЛИВ ДОБАВКИ СПИРТУ ДО БЕНЗИНУ НА ВИКИДИ ЗАБРУДНЮЮЧИХ РЕЧОВИН З ВІДПРАЦЬОВАНИМИ ГАЗАМИ ДВИГУНА З ІСКРОВИМ ЗАПАЛЮВАННЯМ

The constant increasing the number of motor vehicles leads to increase the fuel consumption. Because of oil reserves are exhaustive, the problem of replacing the petroleum fuel with alternative ones is actual. One of which is alcohol fuel. At present, the shortage of motor fuels for internal combustion engines requires their improvment in order to reduce fuel consumption and use the alcohol and various its blends with conventional petroleum-based fuels. The pollutant emissions from motor vehicles are more than a third part of the total emissions to atmosphere and more than 90% of all mobile sources. In addition, motor vehicles are the main source of environmental pollution precisely in places with high concentration of people. It enhances significantly the negative impact of motor transport. In the article it is considered the impact of alcohol additive in standard gasoline on the mass emissions of harmful substances by modern petrol engine equipped with fuel injection system with feedback. The study of using the alcohol and gasoline fuel blends with different content of the alcohol in range from 0 to 36% has been fulfilled. Dependence of load influence on the mass emissions of pollutants is found. Oxygen concentration in fuel are increased when using the alcohols. It contributes to more complete combustion of the fuel and reduction the mass emissions of hydrocarbons, carbon monoxide and carbon dioxide. The disadvantages of the alcohol and gasoline fuel blends include less net calorific value than for conventional gasoline and increased emissions of nitrogen oxides due to free oxygen presence. The mass emissions of harmful substances equivalent to carbon monoxide G∑CO have been slightly increased when using the alcohol and gasoline fuel blends. It is explained by increasing the nitrogen oxides emissions. Objective: To determine the effect of alcohol content in blended fuel for mass emissions of pollutants. Object: environmental performance of spark ignition engine powered by the alcohol and gasoline fuel blends. Subject: determination of expedient alcohol content in the fuel to improve environmental performance of spark ignition engine. The conclusions have been made and the obtained results have been analyzed for further experimental and theoretical studies. KEYWORDS: GASOLINE, ALCOHOL, BLENDED FUEL, EXHAUST GAS, POLLUTANTS, MASS EMISSIONS.

Evaluating the status of gross and net food availability in special reference to carrying capacity of land of Sikkim

In Sikkim, because of vast variation in altitude within short distances and uniqueness of diverse ecological conditions, it supports the cultivation of a large variety of food crops. Even though, the livelihood and economy of the people of Sikkim is still unsustainable. Therefore, an attempt was made to analyse gross and net food availability. For this various secondary data were collected and gross and net food availability was calculated in terms of calorific and monetary value. Carrying capacity of land in terms of gross and net calorific and monetary values was also calculated and analysed. The result shows that the gross and net food availability in Sikkim is very less in commensurate to the existing population. The productivity of food crops has been improved, but the area under it has decreased. The agricultural economy on a whole has been gradually moving from subsistence to commercial orientation over the past three decades, and therefore their sustainability seems comparatively less prosperous in the context of food crops production. Therefore, there is urgent need to look into, for feeding the increasing population.