Development Of Clean Coal Technology Research Articles

Effect of Equivalent Ratio and Hydrocarbon Ratio on Explosive Characteristics of Synthetic Gas

With the development of society, the importance of energy is increasing day by day, and more and more people realize the importance of energy for social development.Therefore, people began to explore energy utilization, energy exploitation, clean energy and other fields.Therefore, in order to use coal resources cleanly and efficiently and reduce the damage to the environment, the development of clean coal technology is particularly important.As a kind of clean energy, syngas has been paid more and more attention, so people pay more and more attention to the safety application of syngas. This paper explores its influence on syngas explosion by changing the equivalent ratio of syngas and the ratio of hydrogen and hydrogen.The results show that the maximum explosion pressure of syngas occurs near the equivalent ratio 1.2, the maximum explosion pressure rise rate reaches the maximum near the equivalent ratio 1.5, and the maximum explosion pressure time reaches the minimum near the equivalent ratio 1.5.The change of hydrocarbon ratio does not shift the equivalent ratio of the above result, but only changes its value. The prediction equations for predicting the maximum explosion pressure under different equivalent ratios are obtained

Study on influencing factors of Coal Microbial Flotation Desulfurization

This study systematically investigates the influence of various factors on microbial flotation desulfurization of coal, with a particular focus on removing organic sulfur. The parameters examined encompass particle size, pretreatment time, bacteria species, bacterial concentration, forms of sulfur occurrence, ash yield, and coal rank. The study aims to develop a thorough understanding of the desulfurization process and establish a theoretical framework for advancing clean coal technology and efficient coal utilization. Stringent control was maintained over parameters such as particle size, pretreatment time, bacterial species, and bacterial concentration. Various forms of sulfur and coal rank were considered to evaluate their impact on desulfurization. Correlation analysis was conducted to investigate the relationship between ash yield reduction and the extent of desulfurization. Thiobacillus ferrooxidans and Rhodotorula mucilaginosa were employed in the experimental setup to assess their efficacy in microbial flotation desulfurization. The results demonstrate that microbial flotation desulfurization achieved the highest removal efficiency for organic sulfur, reaching 79.65%. Notably, the desulfurization of organic sulfur exhibited an increasing trend with decreasing coal rank. Correlation analysis reveals a positive correlation between ash yield and desulfurization, suggesting that high mineral matter content in coal facilitates microbial flotation desulfurization and enhances biological oxidation. Comparative analysis of single strain and mixed strain experiments revealed varying degrees of improvement in desulfurization extent, with the mixed-bacteria system exhibiting the most effective removal of organic sulfur, which suggests that Rhodotorula mucilaginosa can significantly enhance microbial flotation desulfurization. Overall, this research provides systematic insights into the influence of process conditions and geological factors on coal desulfurization. The study establishes a theoretical foundation for the development of clean coal technology and the efficient utilization of coal resources, contributing to the advancement of environmentally friendly practices in the coal industry.

Numerical investigation on flow and heat transfer performance of non-Newtonian Bingham fluid in novel spiral wound tube heat exchangers

Based on the field of the coal chemical industry, exploring the applicability of high-performance heat exchangers for coal water slurry and their flow and heat transfer mechanism is of great significance for promoting the development of clean coal technology. In this paper, the flow pattern and forced convection heat transfer of a pair of tandem heated cylinders with different distances were discussed using the bi-viscous Bingham model by numerical simulation. And a novel spiral wound heat exchanger with variable diameter tubes was proposed. The results illustrate that the heat transfer coefficient under unit pressure drop h/△P of the heat exchanger decreases with the increase of the diameter of the variable tubes. When the diameter of variable tubes is 12 mm, h/△P is 19.83% larger than that of the original structure with uniform tube diameter. The empirical correlation between operating and structural parameters and heat exchanger performance is obtained. The research results provide guidance for the design of coal water slurry preheaters and the structural optimization of spiral wound tube heat exchangers.

Experimental investigation of circulating fluidized bed combustion of dry powders of coal slime

Effective combustion of coal slime in circulating fluidized bed (CFB) boilers is essential for the sustainable development of clean coal technology. To overcome issues related to burning wet coal slime in CFBs, we propose to dry coal slime in a low-temperature drying system and burn the dried fine powders in a CFB with a highly efficient separator. This study reports a series of experiments conducted in a 4MWth pilot-scale CFB combustion test facility to assess the feasibility. The results demonstrate that the dried slime particles, which have a particle size distribution similar to that of circulating ash particles, can be burned stably, efficiently, and cleanly. The combustion of fuels with size distributions similar to that of circulating ash particles increases solids circulation rates, betters solids concentration distribution, enhances heat transfer combustion and improves operation and SO2 and NOx controls. Therefore, the study presents a potential opportunity to advance CFB combustion technology.

Air quality changes in China 2013–2020: Effectiveness of clean coal technology policies

Clean and efficient use of coal in China entered the implementation stage in 2015, and a series of policies were established to promote the sustainable development of clean coal technologies (CCTs). However, the long-term effects of the clean coal technology policies (CCTPs) have not been evaluated, and the outbreak of coronavirus disease 2019 (COVID-19) would bring great uncertainty regarding the effectiveness evaluation. Employing deep learning approaches and spatial autocorrelation analysis, the present work intended to explore the air quality variation before and after the implementation of CCTPs, and investigate the association between air quality and socioeconomic factors to explore the internal mechanism of air quality improvement. Results showed that after implementing CCTPs, the air quality index (AQI) had an average reduction of 18.82%, and the identical drop in air pollution in 2018 implied a 2-year time lag of CCTPs. Additionally, emission reduction and deindustrialization were explored as two promising ways to improve air quality while promoting energy transformation. The findings indicated that the Chinese government ought to pay more attention to long-term plans; industrial restructuring and environmental protection should be insisted upon to realize sustainable energy development. By providing a perspective on air quality improvement after the policies are implemented, this study can lead practitioners and academia to a comprehensive and objective view of clean coal policies.

Study on Pressurized Isothermal Pyrolysis Characteristics of Low-Rank Coal in a Pressurized Micro-Fluidized Bed Reaction Analyzer

The development of clean coal technology has prompted the study of pressurized pyrolysis for coal. Most of the existing studies are non-isothermal kinetic experiments conducted in P-TGA, which cannot reflect the particle movement in actual furnace, so there is a lack of relevant data on pressurized isothermal pyrolysis characteristics. In this work, the effects of pressure on the characteristics of gas release and pressurized isothermal pyrolysis kinetics are explored in P-MBFRA. This work finds that the yields of CO2, CO, CH4, and H2 increases with temperature and pressure. The most probable mechanism function of CO2, CO and CH4 change from shrinking core model to homogeneous model at 1MPa, 0.8MPa and 0.5MPa, respectively, showing that reaction is controlled by chemistry under low pressure but affected by diffusion effect with elevating pressure. The rate constant and activation energy of each gas appear an increasing-decreasing tendency and the difference between activation energy of each gas reduces with pressure. Compared with non-isothermal experiments, the activation energy and pre-exponential factor in P-MBFRA are less than those in P-TGA, indicating P-MBFRA can effectively reduce the diffusion inhibition, and the kinetics obtained is close to the reaction in industrial fluidized bed reactor.

The future of coal supply in China based on non-fossil energy development and carbon price strategies

To realize China’s low-carbon development, coal needs to be produced and consumed in a clean and efficient way. In this paper, a multi-regional coal supply model is developed to gain insights into China’s coal supply system up to 2050. Regional disparity, coal classification, and the development of clean coal technologies are specified in the model. Based on MESSAGEix, this model takes full consideration of coal mining, preparation, transformation, and transportation processes. Moreover, the effects of non-fossil energy development and carbon price are discussed. With the above framework, the future of China’s coal supply system is optimized. Results indicate that: 1) China’s national raw coal production will peak in 2030 under the business-as-usual scenario, while it has already peaked under the GREEN and carbon price scenarios, 2) The amount of coal used in final consumption and transformed into coke decreases, while coal transformed into liquids and SNG increases from 11 Mt in 2015 to 221 Mt in 2050 under the business-as-usual scenario, 3) both non-fossil fuel development and carbon price strategies have a positive effect on coal supply regulation and coal-related GHG emission reduction, 4) carbon price could facilitate the adoption of CCS technology and can effectively reduce coal-related GHG emissions.

Recent advances in high-fidelity simulations of pulverized coal combustion

Although renewable energy has recently attracted a lot of attention, coal-fired power plants will still play an important role in electricity production in the future due to coal’s abundance in the world. However, combustion of pulverized coal is extremely complex which makes experimental measurements very challenging even impossible. As an alternative, computational fluid dynamics (CFD) is a powerful tool to investigate pulverized coal combustion (PCC), and can help to design and develop advanced coal-fired facilities. With the development of computational capacity, high-fidelity simulations of PCC have been developed and significant achievements have been obtained in the recent years. In this review, the recent advances in CFD of PCC, especially in fully-resolved direct numerical simulation (DNS), point-particle DNS and large eddy simulation (LES) of PCC are summarized. The progresses on both numerical methods and coal combustion models are highlighted. The state-of-the-art applications of these high-fidelity simulations are also reviewed, including the investigation of combustion characteristics of pulverized coals, the development of advanced coal combustion models, and the development of clean coal technologies. It is concluded that fully-resolved DNS, point-particle DNS, and LES have their merits and demerits, so the optimal use of each approach depends on specific research purpose. For coal devolatilization and char-oxidation models, the combined models in which advanced models are used to calibrate the kinetic parameters of simple models are quite attractive in terms of computational accuracy and computational burden. For chemical reactions, the flamelet model is popular, but the predictive capability and robustness need to be further improved. Besides, LES is rapidly approaching to simulate industrial PCC. However, the computational cost is still quite expensive, and more efficient algorithms and sub-grid models are required. To this end, DNS database, benchmark measurements, and international collaborations are important. Machine learning may also play an important role in promoting the development of high-fidelity simulations of PCC in the future.

Devolatilization behaviour and pyrolysis kinetics of coking coal based on the evolution of functional groups

Knowledge of the mechanism of coking coal can improve coke and tar production in the coking industry. The evolution of six main functional groups in two coking coals with different ranks was investigated by in situ Fourier Transform Infrared Spectroscopy (FTIR) during non-isothermal pyrolysis in nitrogen gas flow. Different stages in various temperature ranges were proposed based on the evolution of functional groups during coking coal pyrolysis. The evolution of aromatic groups and CO between the two coking coals had the largest difference because of the different coal ranks. The correlations among the evolution of the six functional groups during pyrolysis were also investigated to identify the possible reaction mechanism of coking coal pyrolysis. There were three processes, including evaporation of small molecules, decomposition of oxygen-containing groups, and devolatilization of aliphatic groups during pyrolysis. One-way transport and nth-order chemical reaction models were the main kinetic models of decomposition of the aliphatic groups, CO, CO, and OH. The activation energies of the functional group decomposition in two coking coals were in the range of 25.1–219.4 kJ/mol and 12.3–167.0 kJ/mol. The results that describe the pyrolysis process of coking coals with respect to functional groups can improve the understanding of the pyrolysis mechanism of coking coal and facilitate the development of clean coal technology.

Bibliometric and visualized analysis of China's coal research 2000–2015

Abstract China relies heavily on coal for meeting its huge energy requirements, and strives for the clean utilization of coal. In this paper, a bibliometric and visualized analysis is carried out to quantitatively evaluate the academic output of China's coal research during 2000–2015. All academic publications (in English-language journals) with “COAL” in the title by Chinese authors were extracted from the Web of Science (SCI-EXPANDED) database. After examining 16989 articles published worldwide, China's share reached 28.9% and its annual publications had a more than 15-times increase over this period. ENERGY FUELS, ENGINEERING CHEMICAL, ENVIRONMENTAL SCIENCES and GEOSCIENCES MULTIDISCIPLINARY were the major subject categories. The top 20 journals together accounted for 46.0% of the journal articles by Chinese authors. China held five academic entities among the world's top 10 active institutions, and CHINA UNIVERSITY OF MINING TECHNOLOGY, CHINESE ACADEMY OF SCIENCES, TSINGHUA UNIVERSITY, HUAZHONG UNIVERSITY OF SCIENCE TECHNOLOGY and TAIYUAN UNIVERSITY OF TECHNOLOGY were the five most productive research institutes. The rich and vibrant activity of China's coal research in nearly all aspects of coal science was identified by the Wordle word-cloud analysis, focusing on coal mining, coal gasification or pyrolysis, coal combustion and pollutant control. The word frequencies of COMBUSTION, GAS, MINE, GASFICATION, ASH, PYROLYSIS, COAL-FIRED, BED, POWER, PULVERIZED, MINING and METHANE were the prevalent topics. CARBON, WATER, EMISSION and MERCURY were more prominent than the decade before. The evolution of research hotspots displayed noticeable variations to suit the country's coal research demand. As an international center of coal research, the present capacities and potentials of Chinese scientific community will continuously influence future directions of global coal research and clean coal technology development.

Distribution Route Planning of Clean Coal Based on Nearest Insertion Method

Clean coal technology has made some achievements for several ten years, but the research in its distribution field is very small, the distribution efficiency would directly affect the comprehensive development of clean coal technology, it is the key to improve the efficiency of distribution by planning distribution route rationally. The object of this paper was a clean coal distribution system which be built in a county. Through the surveying of the customer demand and distribution route, distribution vehicle in previous years, it was found that the vehicle deployment was only distributed by experiences, and the number of vehicles which used each day changed, this resulted a waste of transport process and an increase in energy consumption. Thus, the mathematical model was established here in order to aim at shortest path as objective function, and the distribution route was re-planned by using nearest-insertion method which been improved. The results showed that the transportation distance saved 37 km and the number of vehicles used had also been decreased from the past average of 5 to fixed 4 every day, as well the real loading of vehicles increased by 16.25% while the current distribution volume staying same. It realized the efficient distribution of clean coal, achieved the purpose of saving energy and reducing consumption.

Influencing factors of public support for modern coal-fired power plant projects: An empirical study from China

With the development of clean coal technology, modern coal-fired power plants have achieved the similar emission standards as gas power plants. However, due to the impressions of high pollution and high emission in traditional coal-fired power plants, such projects are often opposed by local residents, which hinder the promotion of this technology. This manuscript aims to investigate public attitudes toward these projects and to analyze the influencing mechanisms of the factors of public support. The conceptual model was built with sense of place, trust and environmental attitude as the independent variables, benefit and cost perceptions as the mediating variables and public support as the dependent variable. The model was tested and modified by structural equation modelling. The results revealed that sense of place had a slight indirect impact (−0.043) on public support through benefit perception, whereas trust had a direct impact (0.332) on public support and indirect impacts (0.298) through benefit and cost perceptions. Environmental attitude had indirect impacts on public support through benefit perception (0.180) and cost perception (−0.115). In addition, policy suggestions on decision-making, project publicity and compensation strategy are proposed to enhance public support for similar projects.

PERKEMBANGAN TEKNOLOGI BATUBARA BERSIH BERWAWASAN LINGKUNGAN

Coal has a very important role to meet energy demand in Indonesia, however, it is also the dirtiest fuel among the fossil fuels. As coal utilization continues to increase, pollutants and greenhouse gases emissions from the coal utilization also increase, that would lead to environmental problems. Therefore, development of clean coal technologies for reducing those emissions from coal utilization needs to be considered. The technologies areintended to reduce the policy conflict between continuing coal utilization and protecting environment potential by improving the effectiveness of control technologies and reducing their costs. In addition, the technologies have higher efficiency that would impact on conserving fuels that lead to reducing costs and extension of coal reserve availability.

Clean coal use in China: Challenges and policy implications

Energy consumption in China is currently dominated by coal, a major source of air pollution and carbon emissions. The utilization of clean coal technologies is a likely strategic choice for China at present, however, although there have been many successes in clean coal technologies worldwide, they are not widely used in China. This paper examines the challenges that China faces in the implementation of such clean coal technologies, where the analysis shows that those drivers that have a negative bearing on the utilization of clean coal in China are mainly non-technical factors such as the low legal liability of atmospheric pollution related to coal use, and the lack of laws and mandatory regulations for clean coal use in China. Policies for the development of clean coal technologies are in their early stages in China, and the lack of laws and detailed implementation requirements for clean coal require resolution in order to accelerate China's clean coal developments. Currently, environmental pollution has gained widespread attention from the wider Chinese populace and taking advantage of this opportunity provides a space in which to regain the initiative to raise people’s awareness of clean coal products, and improve enterprises’ enthusiasm for clean coal.

Viscosity Effects of Spray Characteristics in Air-Blast Atomizer

Coal is currently the most widely used and most abundant fossil fuel in the world. It is primarily used for generating electricity at power plants. However, due to problems of pollution and energy consumption, importance has been placed on the development of clean coal technology. Coal-water slurry (CWS), consisting of fine coal and water mixture, is a liquid fuel used to replace heavy fuel oil for boilers and entrained flow gasifiers. Since CWS is a liquid with high viscosity and regular atomizing burners are designed for the use of fossil fuels with low viscosity, it is necessary to design high efficiency atomizing burners specific for CWS. As viscosity is a key factor for atomization characteristics, we used silicon oils of different viscosity as the testing liquids, to study the effect of different atomization parameters on the atomization characteristics. Our results show that, when the gas to liquid ratio (GLR) is high, the existing particle velocity at the central axis is lower than low GLR condition; likewise, the velocity at radial positions is higher of the high-viscosity case. The velocity also increases as the radial distance further increases away from the axis. And decrease as the GLR increases. On the other hand, the distribution of the velocities does not change after the radial distance reaches a certain limit. This limit decreases as the axial length increases. Increasing viscosity increases the inertial force of the liquid fluid, so the momentum of the atomization gas needs to be increased for it to generate enough shear stress on the fluid and to enhance the atomization characteristics.

The impact of the long-term EU target for renewables on the structure of electricity production in Poland

This paper outlines the results of various scenarios for optimizing Poland's future energy system up to 2050. The objective of the study was to demonstrate through the use of models how the level of binding targets for the share of renewable energy (RES) in final energy consumption would impact the evolution of the Polish energy sector. The differences in the compared scenarios consist of the level of RES (renewable energy sources) targets while assuming the same ETS (emissions trading system) CO2 reduction pathways. These scenarios of differing RES targets are compared with other ones where the level of RES obligatory for 2020 has not been increased in the 2020–2050 period. The lack of increasing RES targets applies no preference for any particular technology, and the resulting energy mix is cost-optimal.Potential variations in the energy mix are shown, addressing the fuel and technological structure of electricity production. The analysis presents the costs of electricity generation in the examined scenarios and the level of capital expenditures for the development of new capacities. It examines how RES technologies may develop in Poland with and without the national RES targets after 2020, and the consequences for coal as well as the development of clean coal technologies.

Efficiency improvements for the coal-fired power plant retrofit with CO 2 capture plant using chilled ammonia process

Abstract Development of clean coal technologies for power generation is crucial in meeting the European Union 2050 target to reduce greenhouse gas emissions. CO2 capture technology using chemical solvents currently has the highest potential to decarbonise coal-based power generation. Substitution of amine solvent with NH3 has been proposed as a viable option to reduce the efficiency penalty. In this study, the scenario of a supercritical coal-fired power plant retrofitted with a chilled ammonia process capture plant and CO2 compression unit was modelled in a common simulation environment. To fully assess the integration impact on power plant performance, the pressure loss due to steam extraction has been taken into account by using the Stodola ellipse law. Analysis of a basic integration scenario revealed that the efficiency penalty fell between 10.4% and 10.9% points depending on the stripper pressure. The quality of extracted steam became insufficient to meet the reboiler heat requirement above a stripper pressure of 21.8 bar, and the lowest efficiency penalty was obtained when reboiler condensate was returned to the deaerator in the power plant. In evaluating measures to improve integration, the efficiency penalty was reduced to 8.7–8.8% points through the integration of a single-stage or two-stage auxiliary steam turbine, respectively, and a back-pressure turbine. Nevertheless, the analysis has indicated that the net impact on power plant performance is similar to that of an amine-based post-combustion CO2 capture plant.

Scenario analysis of the CO2 emissions reduction potential through clean coal technology in India's power sector: 2014–2050

The aim of this study is to explore the CO2 emission reduction potential through clean coal technology in India's power sector. A simulation model of India's coal-fired power sector based on system dynamics methodology (Vensim DSS platform) investigates three growth scenarios for coal-fired plants until the year 2050. Three further scenarios consider the market penetration of clean coal technology to investigate CO2 emission reduction until 2050 for each of the growth scenarios. Our analysis indicates that clean coal technology has significant potential for reducing CO2 emissions from India's power sector by accelerating the development of clean coal technology. The future coal demand and coal import requirements for India under different growth scenarios of coal-fired power plants have also been estimated in this study. The study suggests that coal demand and importation from India will increase at a faster pace in the coming decades. According to IPCC's latest assessment report, CO2 emissions must be reduced by between 40% and 70% by 2050 from the 2010 level to limit the global temperature rise to two degrees centigrade relative to pre-industrial levels. Projected carbon emissions in this work from India's coal-fired power plants would exceed their share in global emissions assumed in the IPCC's latest assessment. Our model simulation indicates that only CO2 capture and storage have the potential to reduce the emissions level from India's coal-fired plants to the desired level in the report.

Analysis of Carbon Emission Reduction Potential by Clean Coal Technology in China

This paper analyzes the status quo in China regarding carbon emissions, and discusses challenges facing coal utilization in China. It concludes that the development of clean coal technology is an important means to realize low-carbon emissions in China. Using scenario analysis methodology, this paper presents quantitative analysis of the potential of clean coal technologies for carbon emission reductions in 2015 and 2020. The analysis indicates that high-efficiency combustion in industrial boilers and clean, highly efficient coal-fired power generation should serve as important factors for carbon emission reductions before 2020.

Managing Innovation: Accelerating the Development of Clean Coal Technology

Coal gasification technology concerns the clean, efficient utilization of coal, providing a core solution to address its negative environmental image and impact. Presently, China is pursuing the development of coal gasification technology despite industry setbacks, limited progress and elusive solutions due to limited specialty materials, technological shortfalls and intellectual expertise. The most prominent challenges to overcome include unbalanced research and project scale development issues followed by an excessive emphasis on equipment manufacturing rather than responsible management practices. The ENN Group explored these industry shortcomings to develop a comprehensive management philosophy that is specifically tailored to overcome these fundamental hurdles. Such innovative solutions include the Centralized Innovation Camp, TRIZ (Theory of Inventive Problem Solving) training, Extensive Alliance Network and enhanced process management, focusing upon engineering, quality assurance and process efficiency with the overall objective of industrial scale application. As a result, ENN’s Clean Coal Technologies include: Coal Hydrogasification, Supercritical Coal Gasification, Catalytic Coal Gasification and Underground Coal Gasification, having successfully completed all pilot plant testing requirements and the construction of demonstration commercial units.