Combustion behaviour of some biodesulphurized coals assessed by TGA/DTA

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

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

PAHs in fly ash from lignite combustion

Η έρευνα περιγράφει τον εντοπισμό και προσδιορισμό πολυκυκλικών αρωματικών υδρογονανθράκων (ΠΑΥ) σε ιπτάμενη τέφρα από την καύση λιγνιτών στο θερμοηλεκτρικό σταθμό Μαρίτσα Ίζτοκ- 2. Προσδιορίζεται συνολική περιεκτικότητα σε ΠΑΥ, ~17 pgr/kgr στερεάς ύλης. Περιγράφεται και η κατανομή των ΠΑ Υ ως προς τον αριθμό αρωματικών δακτυλίων (R). Εχει διαπιστωθεί ότι τα οργανικά εκχυλίσματα περιέχουν τρικυκλικούς/τετρακυκλικούς ΠΑ Υ και αλκυλιωμένα παράγωγα τους. Εχει υπολογιστεί και καρκινογόνο δυναμικό, 0,07385 σχετικά με το βενζοπυρένιο = 1. Μέσω αέριας χρωματογραφίας-φασματομετρίας μάζας και προτύπων δευτερίου προσδιορίστηκαν 17 ΠΑΥ, μερικοί από τους οποίους περιλαμβάνονται στη λίστα της USEPA. Οι τιμές που προσδιορίστηκαν είναι χαμηλότερες από τις οριακές τιμές ΠΑΥ σε έδαφος σύμφωνα με τη βουλγαρική νομοθεσία. Παρ 'όλα αυτά χρειάζεται να υπολογίζεται η περιεκτικότητα σε ΠΑ Υ στην ιπτάμενη τέφρα από την καύση λιγνιτών λόγω της τεράστιας ετήσιας παραγωγής υπολειμμάτων από την καύση ανθράκων.This paper describes state-of the art for isolation and determination of polycyclic aromatic hydrocarbons (PAHs) in fly ash from lignite combustion in Maritza East Thermal Power Plant, Bulgaria. Total sum of-17 microg/kg solid by-product PAHs was determined. The profile of PAHs distribution according to the number of aromatic rings in the molecule (R) was determined. Organic extracts were mainly composed by PAHs, their alkylated homologues and heteroatom containing counterparts with dominance of three/four cyclic aromatic compounds. Respectively, relative carcinogenic potency values for PAHs compared to Benzofajpyrene with TEFEPA =1 was not high - 0,07385. Seventeen PAHs, some of them in the list of USEPA for priority pollutants with expressed carcinogenic/mutagenic potential, were identified and quantified by mass spectroscopy (GC/MS/MS) and d-PAHs as internal standards. Determined values for contents of PAHs under regulation were lower than their backgrounds in Bulgarian soils. Nevertheless PAHs in combustion fly ash should be monitored because of high solid by-products annual production and problems of reus

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

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

Reductive Pyrolysis Study of Biodesulfurized Subbituminous Coal

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

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

Biodesulphurized subbituminous coal by different fungi and bacteria studied by reductive pyrolysis

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. Three different types of microorganisms were chosen and maximal desulphurization of 26% was registered. The following biodesulphurization treatments were performed: three types of fungi – “Trametes Versicolor” – ATCC №200801, “Phanerochaeta Chrysosporium” – ME446, Pleurotus Sajor-Caju and Mixed Culture of bacteria – ATCC №39327. A high degree of inorganic sulphur removal (79%) was established and consecutive reduction by ~ 13% for organic sulphur (Sorg) was 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. In order to reach more precise sulphur balance, oxygen bomb combustion followed by ion chromatography was used