The pyrolysis of coal and biomass is generally reported as the mass yield of released chemicals at various temperatures, pressures, heating rates and coal or biomass type. In this work, a new coal-biomass type number, NCT, is introduced. This number is constructed from the mass fractions of carbon, hydrogen, and oxygen in the ultimate analysis. This number is unique for each coal or biomass typ...

Introduction It has been proposed that oxygen functional groups (i.e., carboxylic acids and their salts, phenols, and ethers), prevalent in low rank coals, are responsible for cross-linking reactions that inhibit the efficient conversion of low-rank coals to liquid fuels and chemicals. In the pyrolysis and liquefaction of low-rank coals, cross-linking has been correlated with evolution of CO2 a...

The factors considered are summarized in Table 1. The problem of answering the questions is that multiple chemical reactions occur whose results depend on how the reactants are bound in the coal macromolecular network. Species-selective transport of the reactants and products further complicate the interpretations. In what follows, we have tried to focus on topics where answers are needed or wh...

The effects of different activated carbon (AC) catalysts based on various carbon sources on products yield and chemical compositions of upgraded pyrolysis oils were investigated using microwave pyrolysis of Douglas fir sawdust pellets. Results showed that high amounts of phenols were obtained (74.61% and 74.77% in the upgraded bio-oils by DARCO MRX (wood based) and DARCO 830 (lignite coal based...

This research evaluated the hydrocarbon emission characteristics during pyrolysis of four carbonaceous additives that can be used in green sand foundries. These included a highly volatile bituminous coal, anthracite, lignite and cellulose. The samples were flash pyrolyzed in a Curie-point pyrolyzer at 920 C with a heating rate of about 3000 C/sec. This simulated the fast heating conditions that...

Polycyclic aromatic hydrocarbons (PAHs) are considered to be a group of compounds that pose potential health hazards since some PAHs are known carcinogens. During coal utilization processes, such as coal combustion and pyrolysis, PAHs released may be divided into two categories according to their formation pathways. One category is derived from complex chemical reactions and the other is from f...

We studied the humic-acid fraction isolated from a Spanish leonardite coal (Torrelapaja, Cretaceous basin belonging to the Utrillas facies) using a suite of chromatographic and spectroscopic techniques to characterize the structure of the carbon skeleton and the nature of the sulfur-containing compounds. In particular, analytical pyrolysis coupled to gas chromatography-mass spectrometry was use...

Hydrogen production has gained increasing attention as a potential energy carrier, which can utilize many forms of renewable energy, such as biomass, wind and direct solar power. It has increased its significance as fossil fuels are being used up at a high rate and energy security is of greater importance to the United States and many other countries. Furthermore, hydrogen production offers the...

Understanding and modeling of coal and biomass pyrolysis assume particular importance being the first step occurring in both gasification and combustion processes. The complex chemical reaction network occurring in this step leads to a necessary effort in developing a suitable model framework capable of grasping the physics of the phenomenon and allowing a deeper comprehension of the sequence o...

This laboratory study uses a novel furnace to resolve nitrogen evolution during the three stages of pulverized coal combustion. primary devolatilization, secondary pyrolysis, and com­ bustion The behavior of six coals depicts continuous rank variations, as well as suppressed nitrogen evolution {i'om low volatility coals. During primary de volatilization of any coal, ar­ omatic compounds in tar ...