33 research outputs found

    Combustion behaviour of some biodesulphurized coals assessed by TGA/DTA

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    Thermal analysis, i.e. TGA/DTA is used to study the changes in the combustion behaviour of microbially treated coals. In view of their high sulphur content and industrial significance three samples are under consideration, i.e. one lignite and two subbituminous from different region in Bulgaria. The differences in burning profiles can be related to structural changes resulted from biological treatments. The overall biological treatment generates these changes probably due to the oxidation process. Concerning organic sulphur biodesulphurization there is no change in any drastic mannerof the thermal characteristic parameters. In general, applied biotreatments provoke a complex influence on combustion coal behaviour. From one side a better ignition performance, a minor decrease in higher heating value and diminishing peak temperature of maximum weight loss rate for all biotreated samples are observed. From other side some decrease in the combustibility indicated by an increase in the combustion time and the end of combustion temperature are obvious. Also well determined decrease of self-heating temperature after biotreatments evolves high risk of spontaneous unmanageable coal combustion

    Combustion behaviour of some biodesulphurized coals assessed by TGA/DTA

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    Thermal analysis, i.e. TGA/DTA is used to study the changes in the combustion behaviour of microbially treated coals. In view of their high sulphur content and industrial significance three samples are under consideration, i.e. one lignite and two subbituminous from different region in Bulgaria. The differences in burning profiles can be related to structural changes resulted from biological treatments. The overall biological treatment generates these changes probably due to the oxidation process. Concerning organic sulphur biodesulphurization there is no change in any drastic mannerof the thermal characteristic parameters. In general, applied biotreatments provoke a complex influence on combustion coal behaviour. From one side a better ignition performance, a minor decrease in higher heating value and diminishing peak temperature of maximum weight loss rate for all biotreated samples are observed. From other side some decrease in the combustibility indicated by an increase in the combustion time and the end of combustion temperature are obvious. Also well determined decrease of self-heating temperature after biotreatments evolves high risk of spontaneous unmanageable coal combustion

    Biodesulphurized subbituminous coal by different fungi and bacteria studied by reductive pyrolysis. Part 1: Initial coal

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    One of the perspective methods for clean solid fuels production is biodesulphurization. In order to increase the effect of this approach it is necessary to apply the advantages of more informative analytical techniques. Atmospheric pressure temperature programming reduction (AP-TPR) coupled with different detection systems gave us ground to attain more satisfactory explanation of the effects of biodesulphurization on the treated solid products. Subbituminous high sulphur coal from ‘‘Pirin” basin (Bulgaria) was selected as a high sulphur containing sample. Different types of microorganisms were chosen and maximal desulphurization of 26% was registered. Biodesulphurization treatments were performed with three types of fungi: ‘‘Trametes Versicolor” – ATCC No. 200801, ‘‘Phanerochaeta Chrysosporium” – ME446, Pleurotus Sajor-Caju and one Mixed Culture of bacteria – ATCC No. 39327. A high degree of inorganic sulphur removal (79%) with Mixed Culture of bacteria and consecutive reduction by 13% for organic sulphur (Sorg) decrease with ‘‘Phanerochaeta Chrysosporium” and ‘‘Trametes Versicolor” were achieved. To follow the Sorg changes a set of different detection systems i.e. AP-TPR coupled ‘‘on-line” with mass spectrometry (AP-TPR/MS), on-line with potentiometry (AP-TPR/pot) and by the ‘‘off-line” AP-TPR/GC/MS analysis was used. The need of applying different atmospheres in pyrolysis experiments was proved and their effects were discussed. In order to reach more precise total sulphur balance, oxygen bomb combustion followed by ion chromatography was used

    Withdrawal rates as a consequence of disclosure of risk associated with manipulation of the cervical spine

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    <p>Abstract</p> <p>Background</p> <p>The risk associated with cervical manipulation is controversial. Research in this area is widely variable but as yet the risk is not easily quantifiable. This presents a problem when informing the patient of risks when seeking consent and information may be withheld due to the fear of patient withdrawal from care. As yet, there is a lack of research into the frequency of risk disclosure and consequent withdrawal from manipulative treatment as a result. This study seeks to investigate the reality of this and to obtain insight into the attitudes of chiropractors towards informed consent and disclosure.</p> <p>Methods</p> <p>Questionnaires were posted to 200 UK chiropractors randomly selected from the register of the General Chiropractic Council.</p> <p>Results</p> <p>A response rate of 46% (n = 92) was achieved. Thirty-three per cent (n = 30) respondents were female and the mean number of years in practice was 10. Eighty-eight per cent considered explanation of the risks associated with any recommended treatment important when obtaining informed consent. However, only 45% indicated they always discuss this with patients in need of cervical manipulation. When asked whether they believed discussing the possibility of a serious adverse reaction to cervical manipulation could increase patient anxiety to the extent there was a strong possibility the patient would refuse treatment, 46% said they believed this could happen. Nonetheless, 80% said they believed they had a moral/ethical obligation to disclose risk associated with cervical manipulation despite these concerns. The estimated number of withdrawals throughout respondents' time in practice was estimated at 1 patient withdrawal for every 2 years in practice.</p> <p>Conclusion</p> <p>The withdrawal rate from cervical manipulation as a direct consequence of the disclosure of associated serious risks appears unfounded. However, notwithstanding legal obligations, reluctance to disclose risk due to fear of increasing patient anxiety still remains, despite acknowledgement of moral and ethical responsibility.</p

    Reductive Pyrolysis Study of Biodesulfurized Subbituminous Coal

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    Biodesulfurization is one of the perspective methods for production of friendly fuels. Reductive pyrolysis in mode of atmospheric pressure temperature programmed reduction (AP-TPR) combined with varied detection systems gave us possibility to obtain more s a t isfactory explanation of biodesulfurization effects. AP-TPR coupled “on-line” and “off-line” with potentiometry, massspectrometry and GC/MS analysis with inner sulfur standards for quantification were applied. Subbituminous coal from “Pirin” basin, Bulgaria was treated by three different types of microorganisms with maximal desulfurization effect for total (26%) and organic sulfur (13%). Namely, two types white rot fungi – “Trametes Versicolor , “Phanerochaeta Chrysosporium” and one mixed bacterial culture were used. Improved sulfur balance determination was registered

    Reductive Pyrolysis Study of Biodesulfurized Subbituminous Coal

    No full text
    Biodesulfurization is one of the perspective methods for production of friendly fuels. Reductive pyrolysis in mode of atmospheric pressure temperature programmed reduction (AP-TPR) combined with varied detection systems gave us possibility to obtain more s a t isfactory explanation of biodesulfurization effects. AP-TPR coupled “on-line” and “off-line” with potentiometry, massspectrometry and GC/MS analysis with inner sulfur standards for quantification were applied. Subbituminous coal from “Pirin” basin, Bulgaria was treated by three different types of microorganisms with maximal desulfurization effect for total (26%) and organic sulfur (13%). Namely, two types white rot fungi – “Trametes Versicolor , “Phanerochaeta Chrysosporium” and one mixed bacterial culture were used. Improved sulfur balance determination was registered
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