Accuracy improvement of quantitative analysis of calorific value of coal by combining support vector machine and partial least square methods in laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy(LIBS) is a potential technology for online coal property analysis,but successful quantitative measurement of calorific value using LIBS suffers from relatively low accuracy caused by the matrix effect.To solve this problem,the support vector machine(SVM) and the partial least square(PLS) were combined to increase the measurement accuracy of calorific value in this study.The combination model utilized SVM to classify coal samples into two groups according to their volatile matter contents to reduce the matrix effect,and then applied PLS to establish calibration models for each sample group respectively.The proposed model was applied to the measurement of calorific values of 53 coal samples,showing that the proposed model could greatly increase accuracy of the measurement of calorific values.Compared with the traditional PLS method,the coefficient of determination(R2) was improved from 0.93 to 0.97,the root-mean-square error of prediction was reduced from 1.68 MJ kg-1 to1.08 MJ kg-1,and the average relative error was decreased from 6.7% to 3.93%,showing an overall improvement.

An Experimental Determination of Gross Calorific Value of Different Agroforestry Species and Bio-Based Industry Residues

Solid biomass fuels are useful and cost effective renewable energy source. The energy content of biomass is determined by its calorific value. The objective of this study was to determine experimentally the gross calorific value (GCV) of different agroforestry species and bio-based industry residues that could be used by: a) companies specialized in processing raw biomass solid biofuel production, b) small-scale consumers (households, medium-sized residential buildings, etc.). The fuel samples used were from agricultural residues and wastes (rice husks, apricot kernels, olive pits, sunflower husks, cotton stems, etc.), energy crops and wetland herbs (cardoon, switchgrass, common reed, narrow-leaf cattail), and forest residues (populus, fagus, pinus). The GCV of the bio-mass samples was experimentally determined based on CEN/TS 14918:2005, and an oxygen bomb calorimeter was used (Model C5000 Adiabatic Calorimeter, IKA?-Werke, Staufen, Germany). The GCV of different agroforestry species and residues ranges from 14.3 - 25.4 MJ?kg–1. The highest GCV was obtained by seeds and kernels due to higher unit mass and higher lipid content. Pinus sylvestris with moisture content 24.59% obtained the lowest GCV (13.973 MJ?kg–1).

An Evaluation of the Calorific Values of the Branches and Stems of 11 Tropical Trees

This work investigated and quantified the calorific values of the main branches and trunks of eleven (11) tropical trees in correlation with their chemical composition in order to assess their suitability for use as credible sources of wood fuel. The determination of the carbon, hydrogen, nitrogen, oxygen and sulphur (CHNOS) content of the samples was done using an organic elemental analyser, while an oxygen bomb calorimeter was used to experimentally determine their corresponding gross heat values. The experimental gross heat values for the branches examined ranged from 18,703.37 kJ/kg in Lophira lanceolata to 21,350.35 kJ/kg in Afzelia africana while that of the trunks ranged from 19,747.74 kJ/kg in Tectonia grandis to 22,408.68 kJ/kg in Prosopis africana. These values were within and about the expected ranges observed for tropical trees and may be considered adequate for wood fuel. The general trend in both branches and trunks was that the higher the carbon content, the higher the gross heat value of sample. The absence of sulphur in almost all the samples except, Prosopis africana, (0.055%) was indicative of the fact that the negative environmental impact with respect to harmful emissions of oxides of sulphur is practically non-existent with respect to these species. In the light of the aforementioned variables, the main branches of Afzelia africana (21,350.35 kJ/kg), Nauclea diderrichii (21,157.30 kJ/kg) and Tectonia grandis (20,257.13 kJ/kg) could be used as credible sources of firewood and charcoal production. With respect to the trunks, the timbers in order of preference would ideally be Prosopis africana (22,408.68 kJ/kg), Nauclea diderichii (21,436.42 kJ/kg) and Brachstigia eurychoma (20,924.7 kJ/kg).

Numerical simulation of UCG process with the aim of increasing calorific value of syngas

The determination of operational parameters in the underground coal gasification(UCG)process should be considered in two aspects:first,the total coal in each UCG panel must be gasified and second,the calorific value of the produced gas should be acceptable.The main aim of this study is to present a model that meets these aspects and increasing the calorific value of syngas during this process.In order to achieve those aims,eight different increasing scenarios were devised for total gasification of coal per panel.These scenarios included:increasing oxygen injection rate(scenario 1),the amount of steam injection(scenario 2),operation time(scenario 3),cavity pressure(scenario 4),increase operation time and cavity pressure simultaneously(scenario 5),increase steam injection speed and oxygen injection rate simultaneously(scenario 6),increase in cavity pressure,operating time,steam injection rate and oxygen injection rate simultaneously(scenario 7)and also simultaneous increase in the operating time and steam injection rate(scenario 8).The results showed that for producing syngas with a higher calorific value,the following parameters had the most positive effects respectively:operation time,cavity pressure,steam injection rate and oxygen injection rate.Finally,the model validation was performed for the Centralia LBK-1 UCG pilot and the results showed that this model is very close to reality.

Urban Plant Biomass Residues from the Neotropics and Their Potential for Thermal Energy Generation

The material associated with tree pruning in a city in the Colombian neotropics was characterized in order to determine its energy potential.The species studied for their relevance in the territory were Prosopis juliflora,Licania tomentosa,Terminalia catappa,Azadirachta indica,Pithecellobium dulce,Ficus benjamina and Leucaena leucocephala.Moisture content,bulk density,hygroscopic response,elemental chemical analysis,proximal analysis,calorific value,ease of ignition and combustion,thermogravimetric and heat flow analysis,steam generation capacity,and qualitative analysis of gases(mass spectrometry)were determined.The results that were obtained show high initial moisture contents that vary between 37%and 67%and a variable density(when dry)between 0.21 and 0.41 g/cm3.Chemically,it was shown that all residues have lower carbon and sulfur content compared to a reference mineral coal.However,the residues of some species have higher nitrogen contents compared to the same coal.All biomasses are characterized by their high content of volatile fractions and by having a lower content of inorganic matter compared to carbon.The lower calorific values of these residues are between 14170 and 16928 kJ/kg,which are not negligible compared to other biomasses.This characteristic would be related to the high presence of hemicellulose in the residues.Flue gas monitoring revealed that there are different airflow needs in order to ensure complete combustion.Steam generation tests showed that the calorific value should not be the most relevant criterion to establish the potential use of the waste,since leucaena leucocephala,despite having the highest calorific value,was the material with the lowest performance in steam generation.

Bamboo Biomass for Bioenergy Production in Mauritius

Bamboo, globally renowned as being one of the fastest-growing plants in the world with versatile applications, has gained increasing attention during the past decades. It is being used by millions of people around the globe as a biomass resource for energy production, as timber for furniture making, in the food industry and many more. So far, on the Island of Mauritius, little to no consideration has been given to this fascinating plant. This paper presents the physical and chemical properties of two species of bamboo—Bambusia vulgaris and Bambusia bambos, compared to sugarcane bagasse for bio-energy production. Ten samples of each species were tested for gross calorific value (GCV), moisture, ash and chloride content. The results show that both species have a very good potential for energy recovery with a GCV of 16.77 MJ/kg for Bambusia vulgaris and 17.44 MJ/kg for Bambusia bambos, and are valuable sources of biomass with an average energetic yield of 717.8 GJ/ha/yr and 1587.1 GJ/ha/yr respectively. In comparison, the GCV for sugarcane bagasse was found to be 18.33 MJ/kg with an energetic yield of 824.9 GJ/ha/yr. Simultaneously, a research survey on community acceptance and perception of the Mauritian citizens towards the utilisation of bamboo biomass as an alternative to fossil fuels for bio-energy production was conducted via semi-structured questionnaires. The questionnaires were administered to a total of 54 respondents. 3 women and 3 men were randomly interviewed in each of the 9 districts of the island. The results show that the participants are very much aware of the many issues related to the exploitation of fossil fuels and support the use and implementation of renewable sources of energy for bio-energy production. Eighty percent of the participants supported the implementation of bamboo biomass in the overall energy generation mix in a bold move to lessen their ecological footprint.

Physicomechanical Properties of Rice Husk Pellets for Domestic Combustion in Myanmar

Myanmar produces 26.21 million tons of rice annually that results in 5.24 million tons of remaining rice husk of which only around 30%is used for electricity and heat production in the country.Myanmar needs more energy consumption to develop the agricultural economy and biomass energy in the future of the country.The proximate and ultimate analysis of rice husk and produced rice husk pellets were determined as well as analyzing the physicochemical and mechanical properties.The rice husk pellets without doing size reduction were manufactured in a ring die pellet mill.Loose and pellet-formed rice husk were compared based on the ISO 17225-6 standard for the characterization of herbaceous biomass.Pelletizing increased the bulk density of rice husk by a factor of 4.5.The net calorific value of Myanmar rice husk pellets was 3.67 kW h/kg with a moisture content of 7.48%and the large amount of ash forming constituents.The result showed that the diameter,length,and durability of the produced pellets complied with ISO 17225-6 standard.However,the net calorific value and bulk density could only be partially fulfilled according to the ISO standard depending on the process parameters.

Energetic Study on Jordanian Olive Cake and Woody Biomass Materials

In this work, the potential for energy production in Jordan was explored using four distinct types of biomass samples (olive cakes, woods). The proximate analysis, oil content, and higher heating value were all determined experimentally and compared to other biomass previously published in the literature. The findings appear to be similar to other biomass materials utilized as solid biofuel feed-stock materials. Olive cake and wood samples have lower calorific values than anthracite coal, ranging from 25% to 40% lower. According to the results of this study, olive cake samples had the highest oil extractive content (14.5 wt%), followed by pine and beech woody samples with 8.9 wt% and 3.1 wt%, respectively. The calorific values of the biomass samples tested ranged from 18 to 22 MJ/kg, making them suitable for use as fuel. Moreover, the high volatile matter content (78% to 93%) was appropriate for chemical energy conversion by gasification or combustion process. Jordan can create roughly 8000 tons of pomace oil per year from the waste solid olive cake, based on existing results. Furthermore, the olive cake’s energy potential in Jordan is estimated to be 38 MW based on the higher heating value of the tested samples and the annual quantity of this resource. In the meantime, due to limited annual production, Jordanian firewood has the modest energy potential (2.4 MW).

Assessment of Municipal Organic Solid Waste, as a Potential Feedstock for Briquette Production in Kampala, Uganda

The current shortage of energy resources coupled with environmental degradation problems resulting from deforestation in Uganda has contributed to increased demand for renewable energy resources including municipal organic solid waste and agricultural residues. However, organic waste from Municipal Solid Waste (MSW) may contain contaminants that are harmful to public health and the environment. This study determined the heavy metal concentration in MSW in Kampala City, Uganda. Also, the physicochemical properties of briquettes produced from the MSW were compared with charcoal. The waste samples were collected from residential, institutional and market areas over a period of two weeks. They were then analyzed for the presence of heavy metals. Briquettes were made from the bio-waste and were subjected to calorific and proximate analysis. Results indicated that the mean concentrations of Cd, Cr, Cu, Fe, and Pb were 1.25 mg/kg, 2.04 mg/kg, 38.2 mg/kg, 3.97 mg/kg and 1.99 mg/kg respectively while Hg was not detected. The calorific values of briquettes ranged from 8.9 to 15.3 MJ/kg and were lower than those of charcoal. Heavy metal concentrations in bio-waste collected were below the permissible acceptable limits. These findings indicate that the sampled MSW does not pose a health hazard arising from the presence of such heavy metals and therefore could be a safe source of renewable energy.

Proximate Analysis of Alternatives Cooking Solides Fuels in Sub Saharan by Using Astm Standards

A number of persistent problems have been associated with the supply of traditional domestic fuels in developing countries and particularly in rural areas, including deforestation, scarcity of fuel wood and the high cost of fossil fuels. The use of biomass fuels derived from agricultural waste biomass, generally available in large quantities, has been advocated. This article, therefore, presents some bio-fuels in use or in acceptability test phase in some countries of West Africa and particularly in Senegal but also their characteristics, compared to those of wood or wood charcoal. Samples were prepared and analyzed for moisture content, ash content, volatiles mater, fixed carbon and calorific value. The results indicate that charcoal and bio-charcoal (not mixed with clay) have the best calorific value, while pellets and typha briquettes have the best results in volatile matter and fixed carbon. The results of moisture are generally satisfactory against the use of clay as a binder detrimental to fuel performance. These results suggest that pellets and bio-fuels are used as an energy source for domestic purposes;that the binder is changed in others;pelletizing and briquetting transformations are expanded in other residues such as rice husks, peanut shells.

Physio-chemical characterization of municipal solid waste and its management in high-altitude urban areas of North-Western Himalayas

Municipal solid waste(MSW)management is the most challenging environmental issue in developing countries around global municipalities.In mountainous regions,very few studies can be found and the availability of limited data,because waste management poses different challenges due to different climate,topography,and geographical conditions.This study has been conducted in three urban areas of the Kashmir region(i.e.,Baramulla,Kupwara,and Bandipora)in the western Himalayas.Presently,waste management is underdeveloped and openly dumped in an unscientific manner near to the rivers,streams,and lakes,which increases the threat of contamination to ground and surface water,respectively.The present study aimed to analyze the current scenario of the MSW management system and its waste generation rates.The Physio-chemical characterization of municipal solid waste was carried out by using a quarter and cone method.Proximate analysis of samples was performed by using muffle furnace and bomb calorimeter for chemical analysis,respectively.The findings of the MSW generation of urban areas of Kashmir were approximately 181.43 Mt/day(93.73 Mt/day in Baramulla,57.46 Mt/day in Kupwara,and 30.27 Mt/day in Bandipora),respectively.Further,the findings of MSW showed high organic waste between(10.3%-68.5%),followed by recyclable waste(12.3%-15.30%),and inert waste(8.27%-9.10%),respectively.Also,the chemical characterization results showed average moisture content varying between(47.6%-52.40%)with the lower calorific values of(1017-1175.6 kcal/kg)in the areas mentioned earlier.In conclusion,alternative treatment methods were proposed,for instance,compositing,biomethane plants,the installation of recycling plants,and upgrading the existing dumping sites to sanitary-engineered landfills.