Kinetics of hydrogen donation in the liquefaction of coal

Abstract

The hydroliquefaction of coal has been investigated in a stirred batch reactor at a constant temperature (T = 430 °C) in the presence of tetralin/naphthalene mixtures. Runs were done under either a nitrogen or a hydrogen atmosphere. The pressure was kept constant during the run at a value of either 66 or 110 bar. The tetralin/coal weight ratio ranged between 6.5 and 20.3. Each run lasted =450 min. The experimental results are analyzed by a kinetic model which accounts for the essential features of the coal depolymerization and of the reactions involving the donor. Due to the fact that large tetralin/coal weight ratios were adopted, it is possible to establish the relative importance of the reactions involving the donor itself and those involving donor and coal. The rate constants entering the model are calculated by regressing the experimental data. The analytic equations obtained from the model seem to fit the data satisfactorily.

Reaction network and kinetics of the pyrolysis of Tetralin-naphthalene mixtures in nitrogen and hydrogen atmospheres

“…The loading of the coal mineral matter for runs 6 and 7 is made at the end of the heating period by a technique similar to that described by Gioia and Murena (1988).…”

“…Run 6 has been carried out by running the pyrolysis in the presence of LTA (low-temperature ash) obtained by oxidation at low temperature of the Illinois No. 6 coal utilized in our laboratory (Gioia and Murena, 1988).…”

“…Run 7 is similar to run 6, but a residue of liquefaction runs is used. This residue is obtained by washing with tetrahydrofuran and filtering the solid phase remaining in the reactor at the end of several liquefaction runs (reported by Gioia and Murena, 1988). "Run numbers are as in Table II.…”

“…Since the disappearance of the donor may not be exclusively due to its reaction with coal, it is useful when investigating the kinetics of coal hydroliquefaction to clearly define the reactions undergone by the donor during pyrolysis and the corresponding kinetics, so as to avoid the incomplete or erroneous interpretation of the data. For example, the calculation of donated hydrogen based exclusively on the amount of donor disappeared gives incorrect results if the pyrolysis reactions of the donor are not accounted for (see Gioia and Murena, 1988).…”

Kesikli zaman modelleri kullanılarak Zonguldak, Soma ve Beypazarı kömürlerinin sıvılaştırma mekanizmalarının belirlenmesi

“…Daha önceki çalışmalarda olduğu gibi bu çalışmada da tepkimeler tersinmez ve birinci mertebe kabul edilmiştir. Gioia ve Murene [30] 1988 yılında, kesikli bir reaktörde kömürün hidro-sıvılaştırılmasını incelemişler. Çalışmada modelden elde edilen analitik denklemlerin kömürün hidrosıvılaştırılmasından elde edilen deneysel verilerle uyumluluğu ortaya konulmuştur.…”