Experimental study on hydrogen production by lignite gasification in supercritical water fluidized bed reactor using external recycle of liquid residual
“…One way of producing hydrogen is the so-called coal and supercritical water gasification, which is to convert the coal into the hydrogen-rich gas mixture in the supercritical water atmosphere. The molecular dynamic simulation, the experimental studies, , and the kinetics study of the coal and supercritical water gasification have been carried out recently. At temperature 923 K and pressure 25 MPa, the mixture contains <28% H 2 , <12% CO 2 , and >60% water vapor (in mole fractions).…”
The PVT properties of the (H2 + CO2) mixtures
and the (H2 + CO2 + CH4) mixtures
in the supercritical region of water are significant for making full
use of the gas mixtures in the coal and supercritical water gasification.
We report PVT measurements of the (0.6005 H2 + 0.3995 CO2), (0.6992 H2 + 0.3008 CO2), and (0.6026
H2 + 0.1948 CO2 + 0.2026 CH4) mixtures
(all in mole fractions) at temperature 673 K and pressures of (0.5
to 25) MPa, measured by a modified Burnett method. The upper bounds
of the expanded uncertainties at 95% confidence are 0.2 K for temperature,
0.015·p for pressure, and 0.008·ρ
for density. The density data were compared with those predicted using
the GERG-2008 equation of state. The deviations between the calculated
and experimental data are not more than 0.021·ρ. Furthermore,
the densities were found in accordance with the weighted average of
the components’ existing equations of state using their mole
fractions within 0.0076·ρ for all of the mixtures in this
work. The second and third virial coefficients were determined at
temperature 673 K for hydrogen and all of the mixtures investigated.
“…One way of producing hydrogen is the so-called coal and supercritical water gasification, which is to convert the coal into the hydrogen-rich gas mixture in the supercritical water atmosphere. The molecular dynamic simulation, the experimental studies, , and the kinetics study of the coal and supercritical water gasification have been carried out recently. At temperature 923 K and pressure 25 MPa, the mixture contains <28% H 2 , <12% CO 2 , and >60% water vapor (in mole fractions).…”
The PVT properties of the (H2 + CO2) mixtures
and the (H2 + CO2 + CH4) mixtures
in the supercritical region of water are significant for making full
use of the gas mixtures in the coal and supercritical water gasification.
We report PVT measurements of the (0.6005 H2 + 0.3995 CO2), (0.6992 H2 + 0.3008 CO2), and (0.6026
H2 + 0.1948 CO2 + 0.2026 CH4) mixtures
(all in mole fractions) at temperature 673 K and pressures of (0.5
to 25) MPa, measured by a modified Burnett method. The upper bounds
of the expanded uncertainties at 95% confidence are 0.2 K for temperature,
0.015·p for pressure, and 0.008·ρ
for density. The density data were compared with those predicted using
the GERG-2008 equation of state. The deviations between the calculated
and experimental data are not more than 0.021·ρ. Furthermore,
the densities were found in accordance with the weighted average of
the components’ existing equations of state using their mole
fractions within 0.0076·ρ for all of the mixtures in this
work. The second and third virial coefficients were determined at
temperature 673 K for hydrogen and all of the mixtures investigated.
“…Furthermore, several experimental studies have confirmed that the addition of alkali, especially K 2 CO 3 , can effectively enhance the gasification efficiency of coal, as discussed in Ref. [ 55 , 57 , 59 – 63 ].…”
Section: Poly-generation Based On Scwg Of Coal: Innovational Coal Uti...mentioning
confidence: 88%
“…), showing extremely well adaptabilities. Furthermore, Jin et al [ 63 ] reported that an equivalent gasification efficiency performance can be achieved in a much lower operating parameter (at 530 °C, 25 MPa) with external recycle system, making the SCWG more promising towards industrial-scale application. Fig.…”
Section: Poly-generation Based On Scwg Of Coal: Innovational Coal Uti...mentioning
Coal consumption leads to over 15 billion tons of global CO2 emissions annually, which will continue at a considerable intensity in the foreseeable future. To remove the huge amount of CO2, a practically feasible way of direct carbon mitigation, instead of capturing that from dilute tail gases, should be developed; as intended, we developed two innovative supporting technologies, of which the status, strengths, applications, and perspective are discussed in this paper. One is supercritical water gasification-based coal/biomass utilization technology, which orderly converts chemical energy of coal and low-grade heat into hydrogen energy, and can achieve poly-generation of steam, heat, hydrogen, power, pure CO2, and minerals. The other one is the renewables-powered CO2 reduction techniques, which uses CO2 as the resource for carbon-based fuel production. When combining the above two technical loops, one can achieve a full resource utilization and zero CO2 emission, making it a practically feasible way for China and global countries to achieve carbon neutrality while creating substantial domestic benefits of economic growth, competitiveness, well-beings, and new industries.
“…Research has revealed various cooling methods for electric devices [ 8 , 9 , 10 ]. Some studies have also employed the recycling of various fluids, such as ammonia [ 11 ], CO 2 [ 12 ], and supercritical water [ 13 ] for cooling. Additionally, researchers have introduced a one-section and two-stepwise microchannel for cooling [ 14 ] and a recirculating cooling water system to reduce energy consumption [ 15 ].…”
Electric devices have evolved to become smaller, more multifunctional, and increasingly integrated. When the total volume of a device is reduced, insufficient heat dissipation may result in device failure. A microfluidic channel with a graphene solution may replace solid conductors for simultaneously supplying energy and dissipating heat in a light emitting diode (LED). In this study, an automated recycling system using a graphene solution was designed that reduces the necessity of manual operation. The optical power and temperature of an LED using this system was measured for an extended period and compared with the performance of a solid conductor. The temperature difference of the LED bottom using the solid and liquid conductors reached 25 °C. The optical power of the LED using the liquid conductor was higher than that of the solid conductor after 120 min of LED operation. When the flow rate was increased, the temperature difference of the LED bottom between initial and 480 min was lower, and the optical power of the LED was higher. This result was attributable to the higher temperature of the LED with the solid conductor. Moreover, the optical/electric power transfer rate of the liquid conductor was higher than that of the solid conductor after 120 min of LED operation, and the difference increased over time.
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