Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: organic sulfur

Sortuj według:

Ogranicz wyniki do:

The Role of Organic Sulfur in the Formation of Methane Emissions on the Spontaneous Combustion of Coal

Yusuf Maulana

Journal of Ecological Engineering

2023

Vol. 24, nr 4

192--201

Spontaneous combustion of coal is a phenomenon that often occurs in open coal mining activities, especially strip mining and open pit mining systems which are detrimental to mining companies, the economy, the environment, and society. This phenomenon causes coal mining activities to contribute to CH4 gas emissions in global warming by 11% of total global emission. The purpose of this study was to analyze the role of organic sulfur in the formation of CH4 gas emissions in the spontaneous combustion of coal in the TAL area. The approach is based on a literature review and field survey. The literature review was intended to examine the influence of geological factors, maceral analysis, and depositional environment on the rank and form of coal sulfur, while the field survey was conducted by measuring CH4 gas emissions in 36 samples of spontaneous combustion hotspots. Literature review shows that coal in the TAL area belongs to low rank (sub-bituminous/sub-bituminous B) which has high organic sulfur content in the form of thiother bonds (C-S), especially carbon disulfide (CS2). The average CH4 emission measurement in the field is 6,989 mg/m3, which is still within the limits set by other researchers, between 3,700–34,098 mg/m3. The role of organic sulfur from C–S bonds especially CS2 in the formation of CH4 gas emissions, is very dominant at 93.10% or 6,507 mg/m3 of the total coal sulfur in the TAL area. The emission of CH4 gas in the spontaneous combustion of coal is strongly influenced by geological factors, maceral analysis, and the depositional environment related to the rank and form of coal sulfur. Further, detailed, and comprehensive research on the form of organic sulfur needs to be carried out to mitigate CH4 gas emissions in the spontaneous combustion of coal in the TAL area.

Estimation of hydrous-pyrolysis kinetic parameters for oil generation from Baltic Cambrian and Tremadocian source rocks with Type-II kerogen

Więcław D., Kotarba M. J., Lewan M. D.

Geological Quarterly

2010

Vol. 54, No 2

217-226

Determining kinetic parameters for oil generation from a source rock by hydrous pyrolysis requires a considerable amount of sample (kilograms) and laboratory time (several weeks). In an effort to circumvent these requirements, hydrous-pyrolysis (HP) kinetic parameters for oil generation from Upper Cambrian and Tremadocian source rocks of the Baltic region are estimated by two methods: (1) organic sulfur content in kerogen and (2) HP experiments conducted at 330 and 355°C for 72 h. Estimates for the Upper Cambrian source rocks based on organic sulfur contents gave activation energies from 47 to 56 kcal/mole and frequency factors from 1.156 ' 1025>/sup> to 1.078 ' 1028 m.y.-1 . Tremadocian source rocks based on organic sulfur content gave estimated activation energies from 60 to 62 kcal/mole and frequency factors from 1.790 ' 1029 to 1.104 ' 1030 m.y.-1 . The estimates for the Tremadocian source rocks were less affected by thermal maturation because their low kerogen S/(S + C) mole fractions (< 0.018) remained essentially constant. Conversely, the higher kerogen S/(S + C) mole fractions (>>gt; 0.018) of the Upper Cambrian source rocks decreased with thermal maturation and resulted in overestimation of the kinetic parameters. The second method was designed to estimate kinetic parameters based on two HP experiments. The assumption that the maximum yield in calculating the rate constant at 330°C (k330°C could be determined by a second hydrous pyrolysis experiment at 355°C for 72 h proved not to be valid. Instead, a previously established relationship between Rock-Eval hydrogen index and maximum HP yield for Type-II kerogen was used to calculate k330°C from oil yields generated by the HP experiment at 330°C for 72 h assuming a first-order reaction. HP kinetic parameters were determined from relationships between k330°C and the HP kinetic parameters previously reported. These estimated HP kinetic parameters were in agreement with those obtained by the first method for immature samples, but underestimated the kinetic parameters for samples at higher thermal maturities. Applying these estimated HP kinetic parameters to geological heating rates of 1 and 10°C/m.y. indicated that the Upper Cambrian source rocks would generate oil notably earlier than the overlying Tremadocian source rocks. This was confirmed in part by available data from two neighboring boreholes in the Polish sector of the Baltic.