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.

Optimization study of large-scale low-grade energy recovery from conventional Rankine cycle power plants

2009 ◽  
Vol 34 (12) ◽  
pp. 1071-1087 ◽  
Author(s):  
K. M. Mohamed ◽  
M. C. Bettle ◽  
A. G. Gerber ◽  
J. W. Hall
Keyword(s):  
Energy Recovery ◽  
Power Plants ◽  
Large Scale ◽  
Rankine Cycle ◽  
Low Grade ◽  
Optimization Study

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.

Sustainable Retrofit Design of Natural Gas Power Plants for Low-Grade Energy Recovery

2019 ◽  
Vol 58 (42) ◽  
pp. 19571-19585
Author(s):  
Qiao Q. Tang ◽  
Chang He ◽  
Qing L. Chen ◽  
Bing J. Zhang
Keyword(s):  
Natural Gas ◽  
Energy Recovery ◽  
Power Plants ◽  
Low Grade ◽  
Retrofit Design

Gasification: An alternative solution for energy recovery and utilization of vegetable market waste

2016 ◽  
Vol 35 (3) ◽  
pp. 276-284 ◽  
Author(s):  
Sunil L Narnaware ◽  
NSL Srivastava ◽  
Samir Vahora
Keyword(s):  
Power Generation ◽  
Energy Recovery ◽  
Combustion Engine ◽  
Calorific Value ◽  
Maximum Load ◽  
Thermochemical Conversion ◽  
Small Scale ◽  
Vegetable Waste ◽  
Cold Gas Efficiency ◽  
Gas Efficiency

Vegetables waste is generally utilized through a bioconversion process or disposed of at municipal landfills, dumping sites or dumped on open land, emitting a foul odor and causing health hazards. The presents study deals with an alternative way to utilize solid vegetable waste through a thermochemical route such as briquetting and gasification for its energy recovery and subsequent power generation. Briquettes of 50 mm diameter were produced from four different types of vegetable waste. The bulk density of briquettes produced was increased 10 to 15 times higher than the density of the dried vegetable waste in loose form. The lower heating value (LHV) of the briquettes ranged from 10.26 MJ kg−1 to 16.60 MJ kg−1 depending on the type of vegetable waste. The gasification of the briquettes was carried out in an open core downdraft gasifier, which resulted in syngas with a calorific value of 4.71 MJ Nm−3 at the gasification temperature between 889°C and 1011°C. A spark ignition, internal combustion engine was run on syngas and could generate a maximum load up to 10 kWe. The cold gas efficiency and the hot gas efficiency of the gasifier were measured at 74.11% and 79.87%, respectively. Energy recovery from the organic vegetable waste was possible through a thermochemical conversion route such as briquetting and subsequent gasification and recovery of the fuel for small-scale power generation.

PROSPECTS OF OBTAINING ALTERNATIVE FUEL FROM VARIOUS BIOMASS AND WASTE SPECIES IN AZERBAIJAN

2019 ◽  
pp. 25-41
Author(s):  
O. M. Salamov ◽  
F. F. Aliyev
Keyword(s):  
Power Plants ◽  
Energy Intensity ◽  
Oil And Gas ◽  
Renewable Energy Sources ◽  
Calorific Value ◽  
High Energy ◽  
Energy Sector ◽  
Energy Sources ◽  
Mineral Fertilizers ◽  
Gaseous Fuels

The paper discusses the possibility of obtaining liquid and gaseous fuels from different types of biomass (BM) and combustible solid waste (CSW) of various origins. The available world reserves of traditional types of fuel are analyzed and a number of environmental shortcomings that created during their use are indicated. The tables present the data on the conditional calorific value (CCV) of the main traditional and alternative types of solid, liquid and gaseous fuels which compared with CCV of various types of BM and CSW. Possible methods for utilization of BM and CSW are analyzed, as well as the methods for converting them into alternative types of fuel, especially into combustible gases.Reliable information is given on the available oil and gas reserves in Azerbaijan. As a result of the research, it was revealed that the currently available oil reserves of Azerbaijan can completely dry out after 33.5 years, and gas reserves–after 117 years, without taking into account the growth rates of the exported part of these fuels to European countries. In order to fix this situation, first of all it is necessary to use as much as possible alternative and renewable energy sources, especially wind power plants (WPP) and solar photovoltaic energy sources (SFES) in the energy sector of the republic. Azerbaijan has large reserves of solar and wind energy. In addition, all regions of the country have large reserves of BM, and in the big cities, especially in industrial ones, there are CSW from which through pyrolysis and gasification is possible to obtain a high-quality combustible gas mixture, comprising: H2 + CO + CH4, with the least amount of harmful waste. The remains of the reaction of thermochemical decomposition of BM and CSW to combustible gases can also be used as mineral fertilizers in agriculture. The available and projected resources of Azerbaijan for the BM and the CSW are given, as well as their assumed energy intensity in the energy sector of the republic.Given the high energy intensity of the pyrolysis and gasification of the BM and CSW, at the present time for carrying out these reactions, the high-temperature solar installations with limited power are used as energy sources, and further preference is given to the use of WPP and SFES on industrial scale.

The Effect of Mixing Coal with Biomass in Solid Fuel Briquettes

2013 ◽  
Vol 856 ◽  
pp. 338-342 ◽  
Author(s):  
Chin Yee Sing ◽  
Mohd Shiraz Aris
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Power Plants ◽  
Carbon Dioxide Emission ◽  
Palm Kernel ◽  
Value Added ◽  
Calorific Value ◽  
Fuel Properties ◽  
Biomass Fuel ◽  
Palm Kernel Shell

Burning fossil fuel like coal in power plants released carbon dioxide that had been absorbed millions of years ago. Unfortunately, excessive carbon dioxide emission had led to global warming. Malaysia, as one of the major exporters of palm oil, has abundant oil palm mill residues that could be converted into value-added product like biomass fuel briquettes. Fuel briquette with palm kernel shell and palm mesocarp fibre as its main ingredients showed satisfactory fuel characteristics and mechanical properties as a pure biomass fuel briquette. The effects of adding some coal of higher calorific value to the satisfactory biomass fuel briquette were focused in this study. Various coal-biomass fuel blends were used, ranging from 0wt% coal to 50wt% coal. The fuel properties and mechanical properties of pure biomass briquette and briquettes with different amount of coal added were compared experimentally. From the fuel properties tests, it was found that as the coal content in the briquette was increased, the carbon content and calorific value increased. Mechanical property tests on the fuel briquettes showed a mixture of results, with some favored higher portion of coal in the briquette for better handling, transport and storage properties while some favored greater amount of biomass.

scholarly journals Experimental study of the thermochemical treatment of the low-grade coal prior to boiler combustion at coal-fired power station

2019 ◽  
Vol 109 ◽  
pp. 00119
Author(s):  
Volodymyr Yemelianenko ◽  
Vitalii Pertsevyi ◽  
Oleksandr Zhevzhyk ◽  
Iryna Potapchuk ◽  
Oleksandr Lutai
Keyword(s):  
Experimental Study ◽  
Power Plants ◽  
Thermal Power ◽  
Thermochemical Treatment ◽  
Gas Pressure ◽  
Pulverized Coal ◽  
Time Range ◽  
Low Grade ◽  
Boiler Furnace ◽  
Coal Fuel

Analysis of the perspectives of the coal fuel for thermal power plants is carried out. The necessity of the experimental study for temperature measurement in the boiler furnace. The results of the experimental study are presented: temperature change over time at the burner outlet for different constant pressure value of the backlighting gas, dependence of the temperature at the burner outlet from the backlighting gas pressure for constant concentration value of pulverized coal in coal-air mixture, dependence of the temperature at the burner outlet from the concentration of pulverized coal in coal-air mixture for constant value of the backlighting gas pressure, temperature measurements for constant backlighting gas pressure value, constant value of the concentration of pulverized coal in coal-air mixture when plasmatron is switched and operates for some time range. The results of the study could be applied to the solid fuel treatment for different thermal units.

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