This article investigates the temperature distribution and flowing characteristics of the
dissociated gas and water from hydrate in porous sediment by utilizing a one-dimensional
experimental model setup. With the developed apparatus, the experiments have been run for
the thermal stimulation method by injecting hot water with different temperatures and rates.
The experimental result suggested that the gas production rate increases with time until it reaches
a maximum, and then it begins to decrease. However, the water production rate keeps nearly
constant during the whole production process. The injection water temperature and rate, as well
as the hydrate content in the sediment, all influence the energy ratio of thermal stimulation
production.
The reflectance distribution of coal (the reflectogram), which shows the heterogeneity of coal,
can be represented by several reflectance bins. In this paper, in considering the heterogeneity of
coal, coal is regarded as a mixture of particles. Each particle is characterized by reflectance and
is treated as being homogeneous, without considering the intraparticle heterogeneity. The chemical
compositions (volatile matter (VM), carbon content (C%), ratio of hydrogen to carbon (H/C)) of a
single particle have been estimated from previous works and are used to derive the 13C NMR
parameters of this particle. These parameters are input into the chemical percolation devolatilization (CPD) model to predict the high-temperature VM yields of this particle. The total VM
yields of the coal can be obtained by a summation of the results of all of the particles. In the
experimental portion, the sink−float technique has been used to separate a series of coals into
different maceral-rich fractions, which exhibit very different reflectance distributions. The high-temperature VM yields of these samples have been obtained from drop tube furnace pyrolysis
experiments at 1400 °C to validate the model. The results from pyrolysis experiments and the
single-particle modeling approach show that, under high temperature, the inertinite-rich fraction
produces less VM than does the vitrinite-rich fraction of the same coal. The inertinite-rich fraction
has a lower Q factor, which is defined as the ratio of high-temperature VM yields and proximate
VM, than its vitrinite counterpart. The high-temperature VM yields also have been estimated
from bulk properties of coal samples from the CPD model. These estimations do not agree with
the experimental data. The model could not be applied to those coals that showed abnormal
reflectance features.
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