Recent developments in reduction of sulphur emissions from selected Waterberg coal samples used in South African power plants

Makgato, Stanford S.; Chirwa, Evans M.N.

doi:10.1016/j.jclepro.2020.123192

Cited by 12 publications

(7 citation statements)

References 36 publications

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“…The detected bacteria were M. osloensis COK1, E. aerosaccus COK5, and COK6, so it is assumed that these bacteria are the most adapted in the coal environment than other bacteria in this coal consortium. In another study, the activity of a bacterial consortium on coal continued for up to 18 days (432 h), which significantly reduced almost 70% of the sulfur (Makgato and Chirwa, 2020).…”

Section: Resultsmentioning

confidence: 98%

“…The genus Pseudomonas is known to degrade various aromatic hydrocarbons. They were widely used as a bioremediation agent of environmental pollutants (Wasi et al, 2013) and a member of consortia in coal desulfurization (Kotelnikov et al, 2020;Makgato and Chirwa, 2020).…”

Section: Resultsmentioning

confidence: 99%

“…Higher coal concentrations mean a larger share of coal that microorganisms have to elaborate. They are limited in the face of challenges in the coal's porosity, cracks, and surface areas to further oxidation of sulfur forms, and intermediate products of the sulfur pathway can inhibit their growth (Makgato and Chirwa, 2020). In the three coal media (10%, 15%, and 20%), M. osloensis COK1 was the dominant bacteria in the coal consortium.…”

Section: Resultsmentioning

confidence: 99%

“…Some studies demonstrating the effectiveness of microbial consortia in reducing sulfur content in coal were oriented to the final results (Kotelnikov et al, 2020). Biodesulfurization of a mixed culture bacteria worked more efficiently than physicochemical methods, lowering SO2 emissions by 72.4% and reducing ash content by 33% (Makgato and Chirwa, 2020). Therefore, in the current study, we examined the activity of a consortium of bacteria from coal in batch culture with a medium containing minerals and coal as a sole source of sulfur.…”

Section: Introductionmentioning

confidence: 99%

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The Alternating Growth of Bacteria within a Consortium During Desulfurization of Coal

Pikoli

Aditiawati

Astuti

et al. 2021

Environ. Nat. Resour. J.

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Efforts to reduce organic sulfur in coal are taken through biodesulfurization by using desulfurization bacteria to release covalently-bound sulfur from the coal matrix. Coal is a complex hydrocarbon material that requires collaboration from more than one type of bacteria in a consortium for desulfurization. The current study shows how the individual members of a bacterial consortium obtained directly from coal samples grew on the coal. Mineral medium containing sub-bituminous coal with a concentration of 10%, 15%, and 20% served as a carbon source and the only sulfur to support the consortium's growth. The examination included growth patterns, concentrations of dibenzothiophene as an organic sulfur representative, pH, and sulfate concentration as the sulfur product released into the medium. The growth of individual members of the consortium was observed for 336 h. The consortium grew in all three coal concentrations with slightly different cell growth patterns and the release of dibenzothiophene. Members of the consortium grew alternately and overlapped, which showed possible linkages or dependence on products and existence from the growth of other members. The existence of the primary strain Moraxella osloensis COK1 indicated that they played a role in the activities and growth of other members. The alternating growth is discussed to produce a hypothetical illustration of how several other members play in using sulfur in a well-known desulfurization pathway. In conclusion, this study provides a deeper insight into the value of consortium members individually but growing together while swarming coal as a complex resource to become low-sulfur coal.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Alternating Growth of Bacteria within a Consortium During Desulfurization of Coal

Pikoli

Aditiawati

Astuti

et al. 2021

Environ. Nat. Resour. J.

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“…Moreover, haze reduces the visibility that further afects the economic sectors such as tourism and agriculture [4]. Te combustion of fossil fuels is carried out in several industries which are the main contributors of SO 2 and NO 2 in air [5,6]. Te motorized vehicles and combustion of fossil fuels also emit CO, which is another major pollutant responsible for worsening the air quality.…”

Section: Introductionmentioning

confidence: 99%

Air Quality Prediction Using the Fractional Gradient-Based Recurrent Neural Network

Arora

Singh

et al. 2022

Computational Intelligence and Neuroscience

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In this study, the air quality index (AQI) of Indian cities of different tiers is predicted by using the vanilla recurrent neural network (RNN). AQI is used to measure the air quality of any region which is calculated on the basis of the concentration of ground-level ozone, particle pollution, carbon monoxide, and sulphur dioxide in air. Thus, the present air quality of an area is dependent on current weather conditions, vehicle traffic in that area, or anything that increases air pollution. Also, the current air quality is dependent on the climate conditions and industrialization in that area. Thus, the AQI is history-dependent. To capture this dependency, the memory property of fractional derivatives is exploited in this algorithm and the fractional gradient descent algorithm involving Caputo’s derivative has been used in the backpropagation algorithm for training of the RNN. Due to the availability of a large amount of data and high computation support, deep neural networks are capable of giving state-of-the-art results in the time series prediction. But, in this study, the basic vanilla RNN has been chosen to check the effectiveness of fractional derivatives. The AQI and gases affecting AQI prediction results for different cities show that the proposed algorithm leads to higher accuracy. It has been observed that the results of the vanilla RNN with fractional derivatives are comparable to long short-term memory (LSTM).

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Impact of Organic Sulfur on Coal Graphitization

Li,

Tang,

Liu

et al. 2024

ChemistrySelect

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The utilization of high‐sulfur coal, especially high‐organic coal, has always been a difficult hot spot in the energy field. To study the influence of sulfur in coal on coal‐based graphite products, a series of coal samples with different sulfur content and different degrees of coalification were collected for proximate analysis, ultimate analysis, and sulfur species analysis. The structural characteristics of coal‐based graphite products were analyzed by X‐ray diffraction (XRD). The relationships between the sulfur in coal and the yield (Y), graphitization degree (G), cell diameter (La), and stacking height (Lc) of coal‐based graphite products were explored. The yield of coal‐based graphite ranges from 8.92 % to 64.45 %, and it was found that the yield of coal‐based graphite is not only affected by the degree of coalification, fixed carbon content, and volatile matter content of coal but also significantly inhibited by organic sulfur in coal when the reflectance is less than 2.00 %. The graphitization degree (G) of coal‐based graphite is distributed between 76.02 % and 91.02 %, and positively related to the degree of coalification, and negatively related to the content of volatile matter. Organic sulfur in coal is an unfavorable factor for the graphitization degree (G) of coal‐based graphite. Both the cell diameter (La) and stacking height (Lc) of coal‐based graphite are positively correlated with the degree of coalification and negatively correlated with the volatile matter content in coal. Organic sulfur in coal plays an important inhibitory role on the cell diameter (La) of coal‐based graphite. Still, it has almost no effect on the stacking height (Lc) of coal‐based graphite, resulting in a low ratio of horizontal‐to‐vertical (La/Lc), which is not conducive to the horizontal development of coal‐based graphite cells.

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Recent developments in reduction of sulphur emissions from selected Waterberg coal samples used in South African power plants

Cited by 12 publications

References 36 publications

The Alternating Growth of Bacteria within a Consortium During Desulfurization of Coal

The Alternating Growth of Bacteria within a Consortium During Desulfurization of Coal

Air Quality Prediction Using the Fractional Gradient-Based Recurrent Neural Network

Impact of Organic Sulfur on Coal Graphitization

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