Tons Of Coal Research Articles

Empowering Communities to Reduce Dependence on Unlicensed Mining and Minimize Corporate Losses: A Case Study of PTBA in December 2023

This study aims to analyze the impact of community empowerment programs on reducing dependence on unlicensed mining and to measure the potential losses incurred by PTBA due to these activities. The time sample used in this research is December 2023. A quantitative approach is used to calculate the income earned by the community from six empowerment programs, including bamboo downstream processing, snakehead fish farming, reclamation plant cultivation, maggot farming, quail farming, and eel farming. The total income generated by these programs for 93 beneficiaries reached USD 13,238.22 per month, with an average income per program ranging from USD 153.70 to USD 244.39, which remains below the regional minimum wage (UMR) of Muara Enim Regency, set at USD 233 per month. This income is compared to assess how competitive the alternative livelihoods provided by the empowerment programs are. In addition, this study calculates PTBA’s losses from unlicensed mining in the same month, based on the extraction of 0.175 million tons of coal, the market price of USD 58.28 per ton, and the lost royalties of 8%. The total financial loss reached USD 10.2 million, with USD 815,920 in lost royalties. The analysis underscores the importance of expanding and strengthening community empowerment programs to further reduce unlicensed mining activities, while also mitigating the financial and environmental impacts on the company.

Use of electron microscopy to determine presence of coal dust in a neighborhood bordering an open-air coal terminal in Curtis Bay, Baltimore, Maryland, USA

BackgroundDespite decreasing US consumption, over 90 million metric tons of coal were exported by the US in 2023, requiring significant infrastructure for transport, handling, and storage of coal at export terminals. Residents in Curtis Bay, Baltimore, Maryland, USA live at the fenceline of an open-air coal terminal and have, for decades, reported rapid accumulation of black dust at their homes. Community-level exposure to coal dust originating from coal handling and storage terminals has remained largely unexplored. ObjectivesTo investigate community-identified concerns and use a community-driven approach to determine the presence/absence of coal dust in Curtis Bay surfaces. MethodsPassive settled dust samples were collected from two residential areas, 345 m and 1235 m from the coal terminal, using conductive carbon tape. Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX) of standard reference coal material and a positive control material from the coal terminal in Curtis Bay were used to optimize the morphological and elemental classification criteria for coal dust. A manual SEM-EDX protocol was developed to identify coal particles in settled dust collected on conductive carbon tape in community settings. ResultsSEM-EDX analysis confirmed presence of coal dust sampled at both residential locations. Estimated coal dust particle loading at the proximal and distal site were 13.2 and 3.4 coal particles/mm2, respectively. The coal dust particles identified met specific criteria, including size (>5 μm), morphology, and elemental composition (≥75 % carbon, ≤20 % oxygen). DiscussionThese findings are consistent with longstanding community concerns and lived experiences regarding the presence of coal dust in Curtis Bay, which neighbors a major open-air coal terminal. This approach has potential for other communities neighboring coal terminals to assess similar concerns with residential coal dust exposure.

The status of artisanal coal mining in Afghanistan: Using remote sensing to assess remaining artisanally mineable Jurassic coal resources

Coal mining is critical to the functioning of the current Afghan economy providing jobs, tax revenue, and foreign exchange. Taxes on coal may constitute the Taliban Government’s single largest source of operating income. Prior to the start of mining, Afghanistan had between 215 M and 430 M tonnes of hypothetical category Jurassic coal resources at depths accessible to artisanal miners. Since 1940, between 51 M and 89 M tonnes of coal have been extracted. Technologically primitive mining practices result in suboptimal coal extraction from disorganized room and pillar mines leaving significant amounts of coal unmineable. Frequent tunnel collapse, gas and coal dust explosions, and uncontrolled widespread mine fires have destroyed or made inaccessible significant additional volumes of remaining artisanally mineable resources. The haphazard unmapped development of the existing Jurassic coal makes it impossible to redevelop these fields using more efficient mining technologies. If new mines are to be developed, they will have to tap subsurface coals not accessible to artisanal miners. 66 % of the area mapped as Lower to Middle Jurassic rock does not host outcropping coal beds. This area, as well as some of the areas beneath thin veneers of lowest Cretaceous sediment are potential exploration targets. Jurassic coals are very gassy. Developing coalbed methane prospects is a more effective and less environmentally destructive means to access the energy contained in the Jurassic coals.

Optimasi Desain Geometri Lereng Material Old Dump Pada Usaha Penggalian Ulang Pit X PT. Bukit Asam Tbk

In doing slope design, it is necessary to pay attention to slope geometry and soil shear strength. Determination of slope geometry design also considers the balance between height and slope and production benefits. Research was conducted to analyze slope stability through physical and mechanical properties testing, limit equilibrium, and probabilistic Monte Carlo methods. The surface area of the Overburden stripping area in the 2024 RKP design is 8,172.79 m2. The production target is 2,000,000 tons of coal with a volume of overburden material that must be stripped of 29,000,000 BCM and obtained a Stripping Ratio value of 14.5. The results of the evaluation of the overall slope of the Old Dump material with an overall slope height of 66.582 m, a slope width of 447.69 m, an overall slope of 8.32˚ and a bench width of 25 m, a bench height of 6 m with a comparison ratio of 1:3 and a single slope angle of 18.43˚. Then the redesign was carried out and obtained recommendation results of 64.799 m overall slope height, 303.33 m slope width, 13.02˚ overall slope, and 25 m bench width, bench height at elevation 131-110 of 8 m with a comparison ratio of 1:2, single slope 26.57˚ and at elevation 110-50 of 8 m with a comparison ratio of 1:1.5, single slope 33.69˚.

Low-carbon development path based on carbon emission accounting and carbon emission performance evaluation: a case study of Chinese coal production enterprises.

Carbon emission accounting is the basic premise of effective carbon emission reduction and management. This study aimed to establish the carbon emission model and performance evaluation framework of coal mine production enterprises and clarify the low-carbon development path of enterprises. In this study, we took a typical coal production enterprise (K enterprise) in the Shanxi province of China as the research object. We also estimated the carbon emissions of the enterprise mainly according to the Chinese Carbon Emission Accounting Standard (GB/T 32151.11-2018). The triangular model was used to construct the carbon performance evaluation framework. On this basis, we suggested the enterprise's low-carbon development path. The results showed that (1) the carbon emission of K enterprise in 2021 was 36,875.38 tCO2eq; the carbon emission intensity of each ton of coal produced was 0.089 tCO2eq. The critical carbon emissions were electricity consumption and methane fugitive emissions during production. (2) The evaluation indicators for carbon emission performance revealed an imbalance in K enterprise's economic, energy, and environmental development in 2021. The work on energy saving and consumption reduction was relatively weak. (3) Countermeasures for low-carbon development, including a carbon emission ledger, were proposed based on carbon emission accounting and performance evaluation results. This study can help typical underground coal production enterprises in Shanxi province obtain more accurate carbon emission data, providing practical guidance and reference for the same underground coal production enterprises to improve the carbon emission control effect.

Energy efficiency and greenhouse gas emission reduction potential of solar PV and biomass-based systems for a food processing plant

The industrial sector is one of the most energy-intensive sectors, with a share of nearly 38 % (156 EJ) of all energy used globally in 2020. Historical energy demand and consumption data from a poultry processing plant have been analyzed to lower greenhouse gas emissions (GHG) and reliance on traditional energy sources. The study includes energy, economic, and emissions analyses for (a) solar photovoltaic (PV) systems, (b) biomass fuels, and (c) coal-fired with wood. Fixed, single, and two-axis tracking solar PV systems that are company-owned and funded by banks are considered. The historical energy consumption data of the plant shows that 52.36 % of energy demand is met by electrical energy and 47.63 % by thermal energy. The yearly electricity demand is 9,938 MWh, costs $1,192,560, and emits 5117.6 tCO2. Thermal energy demand is based on an annual use of 898 tonnes of coal and 71.6 tonnes of liquefied petroleum gas (LPG), which costs $ 143,681 and emits 2977.7 tonnes of carbon dioxide (tCO2). Feasibility of 1.3 MW, fixed axis company-owned, solar PV plant shows an annual electricity production of 1876 MWh, GHG emission reduction of 965.9 tCO2 with a payback period of 3.4 years. Biomass system delivers yearly fuel cost savings of $25,724, reducing 2784 tCO2 with a 1.9-year payback period. Co-firing biomass offers a 3.58 % fuel cost saving and 557 tCO2 with a 0.93-year payback period. It concluded that the wood fuel feedstock biomass option is most suitable renewable energy resource for such large-scale poultry facilities.

Assessing the eco-environmental aspects of fossil fuels-based units substitution of Point Aconi thermal power plant by green-based energies: a case study of Canada

AbstractCanada possesses significant potential in harnessing renewable energy from its vast and diverse geography, which can generate clean electricity. This paper presents a model that replaces fossil fuels used in a proposed thermal power plant in Point Aconi, Nova Scotia, with photovoltaic and wind turbine units based on the region’s climate conditions. The research results are based on evaluating multiple thermal power plants worldwide and examining various wind turbines and PV panels from different companies to ensure accuracy. The chosen units that best suit the location’s geographical and biological conditions, transmission, and operation costs demonstrate that the power plant currently consumes approximately 47 tons of coal and petroleum coke per hour. Replacing these materials with the proposed green units makes it possible to reduce environmental pollution by eliminating almost 165 tons of CO2 and other pollutants per hour while increasing the plant’s efficiency and independence from fossil fuel price variations. The presented structure’s ROI is approximately 20 years, which is reasonable compared to the economic and environmental benefits of utilizing such a structure and converting the thermal power plant to green units.

Integrating phase-change thermal storage into the indirect dry-cooling system of a thermal power unit and optimal operation strategy

Extreme conditions (high ambient temperature and crosswind speed) reduce the cooling efficiency of dry cooling towers, consequently impairing the thermal performance of thermal power units (TPUs). Phase-change material thermal storage equipment (PCMTSE) is integrated into an indirect dry-cooling system of the TPU to realize a partial cooling load of the cooling tower, thereby stabilizing and improving the thermal performance of the TPU. A model of the TPU and numerical model of the hybrid indirect dry-cooling system are established and coupled, with the inlet cooling water temperature of the condenser serving as the iterative criterion. Two integration schemes are proposed, one with the PCMTSE downstream (Scheme A) and the other with it upstream (Scheme B) of the dry cooling tower. The results show that Scheme A is recommended owing to its superior efficiency in terms of coal savings. The effects of the unit power load on the coal-savings efficiency of the PCMTSE during its charging and discharging processes have been revealed. Operating the PCMTSE at higher power loads aids in improving the thermal efficiency of the TPU during the PCMTSE charging and discharging processes. The charging process should be started at the “three high” working conditions: a high ambient temperature, crosswind speed, and unit power load. The working conditions that allow only one cooling water pump to operate should first be considered for the discharging process, and the “three high” working conditions should then be selected. The TPU equipped with the PCMTSE can save 11.42 tons and 12.74 tons of coal in two typical extreme daily conditions with the implementation of the proposed operating strategy.

Botswana Coal: Navigating Economic Diversification and Climate Commitments

This paper considers the ethical dilemma posed by the Paris Climate Agreement considering the abundant coal exploitation opportunities in Botswana. The estimated 200 billion tons of coal was initially viewed as an opportunity to diversify the Botswana economy away from diamonds. Coal is currently used locally for electricity production and other small scale domestic uses. This paper mainly discusses thermal coal as opposed to coking coal commonly referred to as Met-coal. Lucrative prices on world markets coupled with demand in India and China for coal, Botswana with its massive coal deposits, one of the largest in world, can develop a new export sector which would diversify the diamond dependent economy. In 2012 the Government of Botswana released a Coal Road Map as it then envisaged coal as one of the more propitious areas for economic diversification. However, the potential to develop this export sector has been seriously challenged by the Paris Climate Agreement decision to move away from coal. In the wake of this treaty countries like China and Japan have refocused their efforts in developing renewable energy and this has negatively hampered Botswana’s economic ambitions.

Co-processing of end-of-life wind turbine blades in portland cement production

The objective of this paper is to evaluate the feasibility of co-processing wind turbine blade (WTB) material in cement manufacturing to provide an end-of-life means to divert the solid waste of decommissioned WTBs from landfills. Many WTBs consist primarily of glass fiber reinforced thermoset polymers that are difficult to recover or recycle. Portland cement is produced world-wide in large quantities, requiring immense quantities of raw materials (mostly calcium oxide and silicon oxide) and kiln temperatures approaching 1,450 °C. This work contributes analyses of WTB material composition, and predicts the energy provided through the combustible components of the WTBs and raw material contributions provided by incorporating the incombustible components of the WTBs to produce cement. Approximately 40 to 50 % of the WTB material will contribute as fuel to cement production, and approximately 50 to 60 % of the WTB material is expected to be incombustible. One tonne of WTB material can displace approximately 0.4 to 0.5 tonne of coal, while also contributing approximately 0.1 tonne of calcium oxide and 0.3 tonne of silicon oxide as raw material to the cement production process. The glass fiber WTB tested had an average boron content of 4.5 % in the ash. The effects of this high boron content on the cement and its production process should be evaluated. Co-processing WTBs in cement plants will slightly reduce combustion-related CO2 emissions due to avoided calcination. It seems feasible to co-process glass-fiber reinforced WTBs in cement production as WTBs provide suitable raw materials and compatible fuel for this process.

Recent Status of Production, Administration Policies, and Low-Carbon Technology Development of China’s Steel Industry

In 2023, China’s crude steel production amount reached 1.019 billion tons, and the energy consumption of China’s steel industry amount reached 561 million tons of coal. China’s steel industry, with its dominant reliance on coal for energy and the primary use of blast furnaces and converters in production processes, as well as its massive output, has become the main field for achieving China’s “carbon peaking” and “carbon neutrality” goals. Firstly, this article summarizes the current production status of the steel industry and the situation of carbon emissions in the steel industry. Secondly, it discusses the dual-carbon policies based on the national and steel industry levels and outlines the future directions for China’s steel industry. Subsequently, it analyzes the current state of research and application of mature and emerging low-carbon technology in China’s steel industry and details the low-carbon plans of China’s steel companies using the low-carbon technology roadmaps of two representative steel companies as examples. Finally, the article gives policy suggestions for the further carbon reduction of China’s steel industry. The purpose of this paper is to show the efforts and contributions of China’s steel industry to the early realization of its “carbon peaking” and “carbon neutrality” goals.

Utilization of Fly Ash and Bottom Ash Waste of PLTU Jeranjang on Geopolymer Paving

Waste is produced as fly ash and bottom ash from coal-fired power stations. PLTU in West Nusa Tenggara uses 13,000 tons of coal in one month, so it can be estimated that Fly Ash waste will be produced around 1,950-2,210 tons. Geopolymer concrete utilizes fly ash as an adhesive to replace Portland cement. Fly ash is used to make geopolymer concrete, which is created by polymerization reactions caused by alkali-aluminosilicate reactions that result in materials with strong structures. In this study, the ratio of the composition of the weight ratio of paste (fly ash and alkaline solution) with aggregate was 35:65. The aggregates used are sand and bottom ash. The test object is a prototype paving block with a specific dimension of 10cm x 21cm x 6cm. Mechanical testing using compressive strength and water absorption testing with a specimen life of 7, 14, 21, and 28 days. Testing of bottom ash and fly ash characteristics in the form of XRF testing. The XRF test results found that the bottom ash and fly ash of PLTU Jeranjang belonged to class F. The average test result of compressive strength at the age of 28 days for mix designs A, B, and C was 8.54 MPa, respectively; 10.29 MPa; and 16.10 MPa. Quality geopolymer paving can be applied to gardens and other interiors used. Another result of the absorption value of Mix design C of 8% shows the addition of fly ash can be utilized in place of some of the used cement in paving blocks that satisfy SNI 03-0691-1996 Quality C criteria.

Rational Mode Parameters of Power Units Operating in Modern Energy Market Conditions

The paper analyzes the operation of condensing and heating turbines in modern energy market conditions with an assessment of the impact of operating parameters of live and secondary steam on economic indicators. It has been shown that when operating at variable loads, the most effective in terms of high-pressure turbines is a rational reduction in the initial pressure ps (sliding pressure), which leads to an increase in thermal efficiency by 1-1.5%. The experimental results of a study of the vacuum effect in the condenser on fuel consumption are presented in the paper as well. Using a specific example of the K-320-26.5 turbine unit, the need for a rational choice of cooling water flow in winter season to ensure optimal vacuum is shown. The issue of choosing a rational steam reheat temperature tr is examined in more detail. It has been established that one of the main reasons for the decrease in the efficiency of turbine units when operating in variable modes is the irrational use of the reheat temperature and the heat of phase transition in the flow part of the low pressure cylinder. The physical explanation of these processes in the turbine as tr decreases is given in detail. It has been shown that, as a result of analyzing the operation of turbine units of various capacities, a rational choice of reheat temperature (reducing tr by 10-20 °C) increases thermal efficiency by 1-2 %, and turbine efficiency - by 0.4-1.0 %. It is recommended to consider the pressure of the hot steam of the high pressure cylinder (рs), the pressure in the condenser (рc=f(tcirc.water)), as well as the reheating temperature tr, which altogether leads to a reduction in heat consumption by 2.5-3.5 % as rational parameters of steam when operating in variable modes. In order to increase the economic efficiency of the operation of turbine units of TPPs and CPPs at reduced loads, it is recommended to revise the regulatory documentation on the current amendments for changes in the reheat temperature. It is stated that with strict adherence to the recommendations discussed above, fuel savings at TTPs and CHPs in Ukraine can amount to 250–300 thousand tons of coal per year.

Использование биологических рабочих агентов для снижения углеродного следа

Introduction. Chemical compounds related to greenhouse gases (CO2, CH4, N2O, some fluorinated F-gases), capturing the energy of the Sun and absorbing infrared radiation, create a greenhouse effect above the Earth’s surface. In order to assess the impact of humanity on the climate system, the carbon footprint indicator is used, which takes into account greenhouse gas emissions from anthropogenic human activities. This indicator is used to estimate direct emissions from technological processes that can be controlled and from indirect emissions that occur during the product lifecycle. One of the promising areas for reducing greenhouse gases can be considered the use of biological working agents. The purpose of the research. Conducting an assessment of the possibilities of using biological working agents to reduce the carbon footprint in mining enterprises. Methodology. The research was conducted on the basis of analyses of literary data from Russian and foreign sources, specific preventive and compensatory initiatives for the absorption of greenhouse gases from the atmosphere based on the participation of biological working agents were considered. Results and discussion. As a result of the research, various technologies for reducing the carbon footprint using biological working agents were considered. Dependences of the carbon footprint on changes in the natural gas content of coal seams for coalmines were obtained. The carbon footprint was calculated when obtaining energy resources for the extraction of 1 ton of coal using various types of fuels, during the burning of rock dumps. It is proposed to use biological working agents to reduce the carbon footprint using various technologies to reduce direct and indirect emissions, as well as to recycle greenhouse gases to obtain alternative energy. The results of the study of the applicability of biological working agents in mining enterprises in order to reduce the carbon footprint are shown. Conclusions. 1. Research has been conducted on the use of various technologies to reduce the carbon footprint using biological working agents in relation to mining enterprises. 2. It has been determined that biological working agents, when used in mining enterprises, can reduce the carbon footprint from direct greenhouse gas emissions by many times, as well as deposit carbon for many years by extracting CO2 and other gases directly from the air, growing trees and plants with high biological productivity capable of sequestering carbon dioxide. 3. It has been found, that biological working agents are able to process CO2 to produce various useful products, as well as utilize greenhouse gases to produce alternative energy.

Water Hyacinth (Eichhornia crassipes) As a Possible Alternative Energy Source: A Case Study for INSEE Cement Manufacturing Plant in Puttalam, Sri Lanka

Cement manufacturing is typically energy-intensive process and currently using alternative fuels partially or totally to replace fossil fuels to reduce the energy and environmental costs. Biomass is one of the main alternative fuel utilized by the cement industry with the potential to replace up to 20% of total energy demand. Water hyacinth (WH) is a problematic invasive alien species in aquatic ecosystems of all climatic zones in Sri Lanka. Because of it is non-edible, rapid growth, and freely available in larger quantities, WH has the potential to be used as biomass energy. Several countries have been studied for WH as feedstock for bioenergy production while physical and chemical composition of WH biomass has been tested by many researchers. However, biomass physiochemical properties may be varied by different place and conditions and there is no significant study for industrial application of WH biomass to burn in cement plant kiln as alternative energy source. Thus, this study aimed to elucidate the potential of WH biomass as an alternative energy source for the INSEE cement plant in Puttalam. The study was conducted in three selected reservoirs namely, Tabbowa reservoir (TR), Murukkuwatawana reservoir (MR), and Nawadankulama reservoir (NR) located in Puttalam district Northwestern province of Sri Lanka. The quantity of fresh and dry WH biomass was estimated with the WH covered area and fresh and dry weights of WH in unit area.WH covered area of in each reservoir during 2020 and 2021 was digitized directly in Google earth satellite images using Google Earth Pro software with help of visual interpretation techniques. WH biomass per unit area were measured by the subjective sampling method. WH samples from each reservoir were collected for analyzing biomass, and to determine the fuel characteristics such as net calorific value (NCV), Chlorine and Sulfur content, moisture, volatile matter, fixed carbon, and ash content. According to the results, the fresh WH biomass was recorded as 692.62, 389.85, 23.58 tons in 2020 and 3570.82, 584.53, 33.31 tons in 2021 in the TR, MR, and NR respectively, while the dry WH biomass was recorded as 41.65, 24.65, 1.31 tons in 2020 and 214.74, 36.96, 1.85 tons in 2021 in the TR, MR, and NR respectively. NCV of the WH composite sample was 12.02 MJ/kg. Moisture content, ash content, chlorine and sulfur content were recorded as 13.56%, 10.95%, 1.06%, and 0.14% respectively. Except for chlorine content, other parameters agreed with the acceptable limits for using WH as an alternative energy source for cement industry. To replace 1 ton of coal, 2.2 tons of dry WH were required from 35 tons of fresh WH biomass while to produce 1 ton of clinker, 0.32 tons of dry WH were required from 5.2 tons of fresh WH biomass. Since relatively large quantities are freely available and with high volatile content and calorific value, WH is suitable as an alternative energy source for cement industry. However, economic feasibility should be studied prior to the commercial application.
 Keywords: Alternative fuel, Biomass, Water hyacinth, Calorific value

Life Cycle Assessment a Coal Mining in East Kalimantan

A Life Cycle Assessment study aimed at identifying the environmental impacts of a coal mining process has been carried out. The scope of the process includes land clearing to coal barging (cradle to gate). The functional unit used is the production of 1 ton of coal. The inventory data in this research is site specific, collected from a mining company located in East Kalimantan during the period September 2022 to June 2023. Impact analysis was characterized using the ReCiPe 2016 midpoint (H) method with the help of OpenLCA v.2.0.2 software. From the impact analysis, it was found that the coal mining operations studied have the potential to produce Fine Particulate Matter Formation (0.122 kg PM2.5eq), Global Warming (73.28 kg CO2eq), Terrestrial Acidification (0.4114 kg SO2eq), Ozone formation-human health and Ozone formation-terrestrial ecosystems (0.54 kg NOx eq), Land Use (4.42×10-4 m2a crop eq), and Water consumption (11.44 m3). The potential for Particulate Matter Formation and Global Warming is generally related to the process of moving materials and water consumption caused by the process of transporting coal. From this research, it was found that the overburden stripping process is an environmental hotspot for the coal mining process because it has the greatest potential impact of all existing processes.

Research on the improvement of carbon neutrality by utilizing agricultural waste: Based on a life cycle assessment of biomass briquette fuel heating system

Various environmental issues caused by global warming demand urgent action to reduce greenhouse gas emissions. Implementing a carbon neutrality strategy emerges as an effective solution to alleviate environmental pollution. The use of biomass briquette fuel significantly contributes to promoting carbon neutrality. In this study, the life cycle assessment (LCA) method was employed to create a model for assessing carbon reduction in biomass briquette fuel heating systems. The findings suggested that the use of agricultural waste briquette fuel for heating has great potential for carbon neutrality. The utilization of 100,000 tons of biomass briquette fuel by a heating enterprise resulted in a remarkable reduction of 335,679 tons of CO2-eq, equivalent to 91,305 tons of carbon. This substitution also displaced 63,558 tons of coal, leading to a reduction of 5460 tons of SO2 and 1012 tons of PM10. The sensitivity analysis identified that transportation distance, energy consumption, and pollutant removal technologies were the primary drivers influencing carbon reduction. Subsequently, some recommendations were proposed to enhance the carbon neutrality of biomass briquette fuel heating systems. These findings have significant implications for achieving carbon neutrality.

Characterization, variations, fluxes, and sources of contaminants in coal mine water of Korba basin, Chhattisgarh, India

AbstractSeveral million tons of coal are extracted which discharge the contaminated mineral water into the environment in the coal mines located in the Korba basin (Chhattisgarh, India) chosen as the study area. The aim of this work is to describe: (i) the physico‐chemical characteristics (pH, EC, TDS, DO, RP, CC (carbonate carbon), OC (organic carbon) F−, Cl−, NO3−, SO42−, SiO44−, PO43−, Na+, K+, Mg2+, Ca2+, Al, As, Sb, Fe, Mn, Zn, Cd, Pb, and Hg) of the coal mine water samples, (ii) spatial, seasonal (i.e. PrM (pre‐monsoon), M (monsoon) and PtM (post monsoon) and temporal (over the period of 2012–2017) variations, (iii) sources of contaminants from fourteen coal mines, (iv) suitability of the water for drinking and other uses, and (v) health impact of the mine water in view of developing remedial approaches.The mine water is neutral in nature with high TDS (total dissolved solid) values ranging from 620 to 13711 mg L−1 due to mainly high carbon content. The concertation of all species lies between 519–11432 mg L−1 with maximum value of OC. The most dominating species were OC, CC, Cl−, NO3−, SO42−, Na, and Ca. Species, that is, F−, OC, Al, Fe, As, Sb, Cd, Pb, and Hg occurred beyond their limits. Their higher concentration in the PtM is observed. Water quality index (WQI) values ranged from 17.52 to 95.68 in the PtM period. 42.85%, 21.42%, and 7.14% of water samples represent “excellent water”, “good water” and “poor water” respectively in the PtM period. In addition, the fertilizer and trace element concentrations in the water samples were compared with the limit values determined for usability as drinking water. Accordingly, it was concluded that it is not suitable for use as drinking water in terms of TDS, F−, and NO3− concentrations. In addition, AsT (total arsenic), F− and NO3− pollutants were detected in the water samples, and it was observed that F− and NO3− ions did not have a carcinogenic effect. A health risk assessment of As has been made, and it is found that adults and children have a low risk of developing cancer from the exposure. However, arsenic has high non‐carcinogenic and potentially harmful effects.

Assessment of Strength and Durability Parameters of Geopolymer Concrete Blocks with Different Sand Replacement Levels

The burned clay brick industry produces approximately 360 billion bricks per year, causing major land degradation and unprocessed pollutants. The quantity of bricks necessitates the use of 15,500 hectares of land. The topsoil necessary to produce traditional brick is 2200 m3 / billion bricks per year, whereas only 0.75 hectare of surface of land is needed to produce millions of clayey bricks each year. Another aspect of environmental degradation was its inefficient use of fly ash, which would be created by thermal power stations (TPS). Around 120 million tonnes of fly ash were produced yearly in India through 260 million tonnes of coal (65 percent of India's annual coal production), covering nearly 15,000 hectares of useable land. Apart from fly ash, a variety of materials, such as clay, silica fume, and bottom ash, could be used as pozzolanic materials which react with both the alkaline activator. The influence of chemical activators, their proportioning, curing conditions, and curing time all impact the strength properties for geopolymer materials. As a result, geopolymer development has a wide range of applications. Compressive strength, water absorption, and sulphate attack were all measured on geopolymer concrete mixes. The objective of this investigation findings was compared to the fly ash based geopolymer concrete block made of natural aggregate with different replacement levels of fine aggregate as natural sand, manufactured sand and Ecosand with required mix proportion are all within the IS 15658 guidelines.

Characteristics Analysis of Integrated CAES and CFPP Trigeneration System Considering Working Conditions and Application Scenarios

To meet the goal of worldwide decarbonization, the transformation process toward clean and green energy structures has accelerated. In this context, coal-fired power plant (CFPP) and large-scale energy storage represented by compressed air energy storage (CAES) technology, are tasked with increasing renewable resource accommodation and maintaining the power system security. To achieve this, this paper proposes the concept of a CFPP–CAES combined cycle and a trigenerative system based on that. Considering the working conditions of the CFPP, thermal characteristics of three typical operation modes were studied and some general regularities were identified. The results of various potential integration schemes discussion indicated that extracting water from low-temperature points in the feedwater system to cool pressurized air and simultaneously increase the backwater temperature is beneficial for improving performance. In addition, preheating the pressurized air before the air expanders via low-grade water in the feedwater system as much as possible and reducing extracted steam contribute to increasing the efficiency. With the optimal integration scheme, 2.85 tonnes of coal can be saved per cycle and the round-trip efficiency can be increased by 2.24%. Through the cogeneration of heat and power, the system efficiency can reach 77.5%. In addition, the contribution degree of the three compression heat utilization methods to the performance improvement ranked from high to low, is preheating the feedwater before the boiler, supplying heat, and flowing into the CFPP feedwater system. In the cooling energy generation mode, the system efficiency can be increased to over 69%. Regardless of the operation mode, the benefit produced by integration is further enhanced when the CFPP operates at higher operating conditions because the coupling points parameters are changed. In addition, the dynamic payback period can be shortened by 11.33 years and the internal rate of return increases by 5.20% under a typical application scenario. Regarding the effect of different application scenarios in terms of economics, investing in the proposed system is more appropriate in regions with multiple energy demands, especially heating demand. These results demonstrate the technical advantages of the proposed system and provide guiding principles for its design, operation, and project investment.