Sulfur analysis of Bolu-Mengen lignite before and after microbiological treatment using reductive pyrolysis and gas chromatography/mass spectrometry

Atmospheric pressure-temperature programmed reduction coupled with on-line mass spectrometry (AP-TPR/MS) is used for the first time on microbiologically treated coal samples as a technique to monitor the degree of desulfurization of the various sulfur functionalities. The experimental procedure enables the identification of both organic and inorganic sulfur species present in the coal matrix. A better insight in the degradation of the coal matrix and the accompanying processes during the AP-TPR experiment is obtained by a quantitative differentiation of the sulfur. The determination of the sulfur balance for the reductive pyrolysis gives an overview of the side reactions and their relative contribution in the total process. The volatile sulfur species are unambiguously identified using AP-TPR off-line coupled with gas chromatography/mass spectrometry (GC/MS). In this way, fundamental mechanisms and reactions that occur during the reductive pyrolysis could be quantified, explaining the differences in AP-TPR recoveries. Therefore, this study gives a clearer view on the possibilities and limitations of AP-TPR as a technique to monitor sulfur functionalities in coal

Literature survey of properties of synfuels derived from coal

A literature survey of the properties of synfuels for ground-based gas turbine applications is presented. Four major concepts for converting coal into liquid fuels are described: solvent extraction, catalytic liquefaction, pyrolysis, and indirect liquefaction. Data on full range syncrudes, various distillate cuts, and upgraded products are presented for fuels derived from various processes, including H-coal, synthoil, solvent-refined coal, donor solvent, zinc chloride hydrocracking, co-steam, and flash pyrolysis. Some typical ranges of data for coal-derived low Btu gases are also presented

Ko-pyrolýza vybraných polymerů s uhlím

Amount of polymer waste increase every year and for this reason upgrading of this waste is a necessity. Nowadays waste disposal and incineration of polymers waste are the most frequently used methods which (i) did not allowed chemical and energy utilization and (ii) are not environmentally friendly. Pyrolysis and co-pyrolysis provide an attractive way to dispose of and convert polymer waste and coal into higher value fuel and the specific benefits of this method potentially include many environmental friendly advantages. Pyrolysis and co-pyrolysis has been studied using termogravimetry apparatus NETZCH TG-DTA STA 409 EP. The pyrolysis of all polymers except for scrap tyres was a one-step process and temperature range was narrower than for coal pyrolysis. The overlapping temperature range for pyrolysis of polymers and coal was 200–600°C. The synergic effect and kinetics of co-pyrolysis of polymers and coal has been studied in the given temperature range. The addition of polymers to coal led to (i) the enhancement of weight loss of brown coal, (ii) the shift of temperature of the max pyrolysis speed and (iii) the slight influence of EA of coal pyrolysis.Množství odpadních polymerů každoročně stoupá a jejich recyklace je velmi důležitá. V dnešní době je největší část těchto odpadů ukládána na skládky nebo spalována. Tyto dvě metody však nejsou příliš vhodné (nedochází k chemickému ani energetickému využití materiálu) a nejsou ani šetrné k životnímu prostředí. Pyrolýza a ko-pyrolýza jsou vhodné recyklační metody umožňující přeměnu odpadních polymerů a uhlí na paliva s vyšším energetickým obsahem a jsou šetrné k životnímu prostředí. Pyrolýza a ko-pyrolýza vybraných polymerních materiálů s hnědým uhlím byla studována pomocí dynamické termogravimetrie na přístroji LECO TG-DTA STA 409 EP firmy NETZCH. Pyrolýza polymerů, kromě odpadních pneumatik, probíhala v jednom stupni a v užším teplotním intervalu než pyrolýza uhlí. Teplotní interval, kdy docházelo k pyrolýze polymeru i uhlí byl 200-600°C. V tomto teplotním intervalu byla rovněž studována kinetika ko-pyrolýzy a synergický efekt studovaných polymerů a hnědého uhlí. Nejvyšší pozitivní synergický efekt vedoucí ke zvýšení hmotnostního úbytku hnědého uhlí a rychlejší pyrolýzy při nižších teplotách měl ze studovaných polymerů polypropylen

Coupled effect of torrefaction and blending on chemical and energy properties for combustion of major open burned agriculture residues in Thailand

Thailand is an agriculture-based country. It produces large amounts of open burned agricultural residues. A strategy to use them as biofuel all year round is to enhance their fuel properties by coupling blending and thermochemical pre-treatment. In this study, the pyrolytic behaviour of major residues (napier grass , rice straw, cassava stalks and corn cob) exposed to a high torrefaction temperature (300°C) was investigated for various blending ratios, i.e. 100:0, 50:50 and 70:30. The release of chlorine was quantified for each biomass blend, including, a new fouling risk index ratio. Also, the synergistic effects of both ignition and burnout temperatures were analysed. Rice starw and napier grass were found to be characterised by a high ash content and so large amounts of solid yield after torrefaction. Raw biomasses and untreated biomass blends were found to be less suitable as biofuel than torrefied biomasses. The ratio K2O:SiO2, indicator of fouling risk during combustion, was found to be low for all torrefied blends. The HHV:Cl ratio, indicator of combustion quality, indicated that NG mixed with RS (50:50 proportion) is the most promising blend. Significant synergetic effects were observed for biomasses mixed before torrefaction. The burnout temperatures for raw and torrefied biomasses were identified in the range 773-787 °C and 786-795 °C. (Résumé d'auteur

Relevance of the composition of municipal plastic wastes for metallurgical coke production

This study is concerned with the effects of the composition of mixed plastic wastes on the thermoplastic properties of coal, the generation of coking pressure and the quality of the resulting cokes in a movable wall oven at semipilot scale. The mixed plastic wastes were selected to cover a wide spectrum in the relative proportions of high- and low-density polyethylenes (HDPE and LDPE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET). From the results it was deduced that the reduction in Gieseler fluidity in the coal blend is linked to the total amount of polyolefins in the waste. It was also found that these thermoplastics increase the pressure exerted against the wall in the course of the coking process and that coke quality is maintained or even improved. However, when the level of aromatic polymers such PS and PET are increased at the expense of polyolefins, the coking pressure decreases. Thus, the amount of aromatic polymers such as PS and PET in the waste is critical, not only for controlling Gieseler fluidity and coking pressure, but also for avoiding deterioration in coke quality (reactivity towards CO CRI and mechanical strength of the partially-gasified coke CSR). An amount of polyolefins in the waste lower than 65 wt.% for a secure coking pressure is established

Pyrolysis and char oxidation of biomass and coal blends: kinetic study using thermogravimetric analysis

Vietnam as an agricultural country has a high potential in biomass, especially agricultural and forestry wastes. This resource offers a promising way to develop co – combustion technology of biomass and coal in Vietnam and thus tackle the environmental issues. A fundamental research was established to study combustion of Vietnamese rice straw and coal. Blends was made by mixing manually 50% wt. of rice straw and 50% wt. of coal. Pyrolysis in inert gas, char oxidation in oxidizing gases (10 % O2 in N2) and combustion process in oxidizing gases (10 % O2 in N2) were implemented. A particular attention was paid to the behaviour of rice straw/coal blends during thermochemical transformation. Concerning pyrolysis process, the char yield of the mixture is equivalent to weighted sum of the char yield of two solid fuels. During the combustion of the blends, we observed a coupling between pyrolysis and char oxidation. The exothermic oxidation reactions could overheat the sample itself and accelerate the pyrolysis and char oxidation kinetics