Elucidation of Hydrogen Mobility in Coal Using a Tritium Tracer Method. 1. Hydrogen Exchange Reaction of Coal with Tritiated Water

Abstract

The hydrogen exchange of coals with water was investigated using a tritium tracer method to estimate the mobility of hydrogen in coals. The reactions at several temperatures between 50 and 300 °C were carried out using a glass batch reactor and a pulse flow reactor, respectively. At lower temperatures, the ratio of hydrogen exchange of coal with water increased with a decrease in rank of coals and tended to change with respect to the content of functional groups such as hydroxyl group, thiol, amino group, and carboxylic acid in coal. From the results obtained from the hydrogen exchange of model compounds of the functional groups present in coal, it is proposed that the hydrogen only in the functional group was exchangeable at lower temperature while the hydrogen in aromatic ring substituted by functional groups also became exchangeable at 300 °C. It was found that the use of the pulse flow reactor as well as the glass batch reactor was very useful facile and convenient methods to trace the hydrogen exchange between coal and water.

Evaluation of Drying Induced Changes in the Molecular Mobility of Coal by Means of Pulsed Proton NMR

“…Nature of Mobile Coal Hydrogen. It is a well-established fact that exposing hydroxyl groups in coal to liquid or gaseous D 2 O can deuterate them. − Figure shows the change in the IR spectra of deuterated YL coal. The peak around 2500 cm -1 grows with the length of exposure, while the peak due to OH groups around 3400 cm -1 diminishes in size.…”

Elucidation of Hydrogen Mobility in Functional Groups of Coals Using Tritium Tracer Methods

“…In the present paper, we review our recent studies concerning the hydrogen exchange reaction of various coals with tritiated water and gaseous hydrogen to estimate the amounts of hydrogen in functional groups of coals. − In the pressurized system with tritiated water using the batch reactor, aromatic hydrogen around the functional groups in coal can be determined. This study is the original contribution for this paper.…”

Reactions of Tetralin with Tritiated Molecular Hydrogen on Pt/Al2O3, Pd/Al2O3, and Pt−Pd/Al2O3Catalysts

“…As reported recently, tritium tracer methods are very effective for the quantitative tracing of hydrogen behavior of coal and tetralin during coal liquefaction in a batch reactor. − Further, tetralin is known to be a simple and good solvent in the coal liquefaction process and can be taken as a typical model compound representing the aromatic compounds in distillate fuels, especially in fcc-LCO. Recently, we reported that the hydrogen mobility of tetralin can be elucidated using a flow reactor .…”