scholarly journals Characterization and optimization of calorific value of low grade coal by statistical experiment and modelling

2020 ◽  
Vol 26 (2) ◽  
pp. 200070-0 ◽  
Author(s):  
Sangchul Park ◽  
Qammer Zaib ◽  
Hung-Suck Park
Keyword(s):  
Environmental Factors ◽  
Power Plants ◽  
Calorific Value ◽  
Weather Conditions ◽  
Proximate Analysis ◽  
Low Grade ◽  
Statistical Experimental Design ◽  
Optimum Conditions ◽  
Statistical Experiment ◽  
Gross Calorific Value

The effects of environmental factors (temperature, humidity, and airflow) on gross calorific value (GCV) and proximate analysis of low grade coal were systematically investigated. The factorial experiments were conducted according to the statistical experimental design. The results were empirically modeled, statistically tested, and experimentally verified to quantify the change in GCV and proximate analysis of coal directed by environmental factors. The GCV of the coal were most affected by the humidity followed by the temperature. The GCV was increased from 5,365 to 5,986 (kcal/kg) through the decrease in humidity from 80 to 29 (% R.H.) and increase in temperature from 28 to 36 (°C). This increase in GCV could be attributed to the decrease in moisture content of the coal from 16.2 to 7.1 (%). Also, the optimized environmental conditions were identified where GCV ≈ 6,000 kcal/kg of the coal could be obtained. This study can be helpful in (i) managing the variability in GCV of a coal at different places, environment, and weather conditions and, thereby, settling the disputes between buyers and sellers over its variability and (ii) in maintaining the optimum conditions to enhance the GCV of the low grade coal in the power plants.

Evaluation of the washability characteristics of Khushab coal (Pakistani) by heavy media separation process

2017 ◽  
Vol 28 (5-6) ◽  
pp. 598-607 ◽  
Author(s):  
Hafiz Sana ◽  
Sumaira Kanwal ◽  
Javaid Akhtar ◽  
Naseer Sheikh ◽  
Shahid Munir
Keyword(s):  
Energy Recovery ◽  
Power Plants ◽  
Calorific Value ◽  
Environmental Issues ◽  
Thermochemical Conversion ◽  
Low Grade ◽  
Particle Sizes ◽  
Clean Coal ◽  
Recovery Schemes ◽  
Combustion Technique

The use of high-sulfur Pakistani coals can cause serious problems of slagging and fouling in thermochemical conversion reactors along with environmental issues like acid rain, etc. In this study, a pre-combustion technique, namely heavy media separation, is employed for the cleaning of low-grade Pakistani coal. Six crushed coal samples of different particle sizes were individually subjected to heavy media solutions of ZnCl2 of different specific gravities. It was found that the sample with a particle size of −6.25+4 mm at specific gravity of 1.4 produced the optimum float product as clean coal, showing 83.53% yield of clean coal with 1.24% ash and 1.0% sulfur contents. An overall reduction of 91.68% in ash and 86.11% sulfur contents was obtained. Moreover, up to 19.3% enhancement of gross calorific value was achieved. The resultant clean coal can be used in various energy recovery schemes in Pakistan such as coal-fired power plants and cement industries.

scholarly journals Exergy efficiency analysis of lignite-fired steam generator

2018 ◽  
Vol 22 (5) ◽  
pp. 2087-2101
Author(s):  
Drenusha Krasniqi-Alidema ◽  
Risto Filkoski ◽  
Marigona Krasniqi
Keyword(s):  
Steam Generator ◽  
Flue Gas ◽  
Power Plants ◽  
Thermal Power ◽  
Calorific Value ◽  
Feed Water ◽  
Low Grade ◽  
Gas Temperature ◽  
Steam Generators ◽  
Energy And Exergy

The operation of steam generators and thermal power plants is commonly evaluated on a basis of energy analysis. However, the real useful energy loss cannot be completely justified only by the First law of thermodynamics, since it does not differentiate between the quality and amount of energy. The present work aims to give a contribution towards identification of the sources and magnitude of thermodynamic inefficiencies in utility steam generators. The work deals with a parallel analysis of the energy and exergy balances of a coal-fired steam generator that belongs to a 315 MWe power generation unit. The steam generator is de-signed for operation on low grade coal - lignite with net calorific value 6280 to 9211 kJ/kg, in a cycle at 545?C/177.4 bar, with feed water temperature 251?C, combustion air preheated to 272?C and outlet flue gas temperature 160?C. Since the largest exergy dissipation in the thermal power plant cycle occurs in the steam generator, energy, and exergy balances of the furnace and heat exchanging surfaces are established in order to identify the main sources of inefficiency. On a basis of the analysis, optimization of the combustion and heat transfer processes can be achieved through a set of measures, including retrofitting option of lignite pre-drying with flue gas and air preheating with dryer exhaust gases.

Hydrogen and Syngas Generation from Gasification of Coal in an Integrated Fuel Processor

2014 ◽  
Vol 625 ◽  
pp. 644-647 ◽  
Author(s):  
Sujan Chowdhury ◽  
Abrar Inayat ◽  
Bawadi Abdullah ◽  
Abdul Aziz Omar ◽  
Saibal Ganguly
Keyword(s):  
Coal Gasification ◽  
Fixed Bed ◽  
Calorific Value ◽  
Volatile Matter ◽  
Proximate Analysis ◽  
Fixed Carbon ◽  
Gross Calorific Value ◽  
Fuel Processor ◽  
New Energy

Hydrogen is a clean and new energy carrier to generate power and effectively turned out through the gasification of organic material such as coal. The main objective of this manuscript is to present an analysis of the coal gasification for the generation of high-purity hydrogen in a lab-scale fixed-bed downdraft gasifier. Better understanding of the rank, formation, structure, composition and calorific value and method of analysis of the material is crucial for the proper utilization of these resources requires. Traditionally the quality of the Coal samples has been determined by their physical and proximate analysis, such as, bulk density, free swelling index, gross calorific value, sulfur, moisture, fixed carbon, volatile matter and ash content. In this study, coal is partially oxidized and ultimately converts into hydrogen rich syngas (CO and H2). As well, approximately 220 kg h−1 of coal would be gasified at 673–1073 K and 46.2 atm with the reactor volume 0.27m3 to obtain approximately 3.8×105 kcal h−1 of thermal energy during over 67% syngas generation with the generation of 110kW electrical powers.

scholarly journals Potential of bamboo species for the production of briquettes

2019 ◽  
Vol 49 ◽  
Author(s):  
Martha Andreia Brand ◽  
Ailton Leonel Balduino Junior ◽  
Daniela Leticia Nones ◽  
Angela Zakostelsky Neves Gaa
Keyword(s):  
Bulk Density ◽  
Compression Strength ◽  
Raw Materials ◽  
Calorific Value ◽  
Proximate Analysis ◽  
Bamboo Species ◽  
Gross Calorific Value ◽  
Promising Alternative ◽  
Bambusa Vulgaris ◽  
Phyllostachys Bambusoides

ABSTRACT Bamboo is a versatile plant that is widely used in many areas for feeding, manufacturing of utensils, construction and environmental purposes. The energetic use of bamboo stalks or residues from other applications is a promising alternative and compatible with sustainable development principles. This study aimed to evaluate the potential of four bamboo species (Bambusa vulgaris, Phyllostachys bambusoides, Phyllostachys edulis and Phyllostachys nigra) for briquette production. The following properties were evaluated: moisture content, bulk density, compression strength, proximate analysis, gross calorific value and energetic density. The results showed numbers ranging from 1.109 g cm-3 to 1.228 g cm-3 for bulk density, 4.68 MPa to 5.82 MPa for compression strength, 79.01 % to 82.25 % for volatile content, 15.26 % to 20.18 % for fixed carbon content, 0.38 % to 2.49 % for ash content, 4,571 kcal kg-1 to 4,716 kcal kg-1 for gross calorific value and 5.08 Gcal m-3 to 5.84 Gcal m-3 for energetic density. The briquettes produced from P. nigra presented the best energetic quality, followed by briquettes from P. edulis, P. bambusoides and B. vulgaris. Overall, it may be said that the four bamboo species can be used as alternative raw materials for energy generation.

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