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A highly active catalyst Keggin type POM-based inorganic-organic compound POM@MOF-199@LZSM-5(PMZ) has been prepared and applied in the catalytic oxidative desulfurization system. Structure and properties of catalyst were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption, scanning electron microscopy (SEM),...
The attractive Zhundong coalfields located in the Northwestern PR China are featured by many high qualities, such as low contents of mineral matters and total sulfur. However, a significant amount of sodium species are also embedded in the Zhundong coals (ZDC), which has been a barrier for efficient utilization of them. In this work, to better understand the detailed behaviors of sodium species and...
Gasification has been deemed as the most promising method for the thermochemical conversion of Shanxi high ash coals, although the use of these high ash coals leads to high consumption of coal and oxygen, low syngas yield and cold gas efficiency. In order to improve gasification efficiency, it is necessary to reduce the ash content of these Shanxi high ash coals. In this work, three representative...
In order to study the necessity of hydrogen source at preheating stage of direct coal liquefaction, product distribution, hydrogen consumption, and coal structural change of Hami sub-bituminous coal (HM) with 1-methylnaphthalene (1-MN) and tetralin respectively were investigated under hydrogen and nitrogen atmosphere. The results show that oil could be generated from coal itself with 1-MN under N2...
Lignite, a suitable feedstock for direct coal liquefaction (DCL), is usually rich in sodium and calcium species. To better understand chemical transformation of inherent sodium and calcium species during DCL, two lignites rich in sodium and calcium species were liquefied in this work. The results show that both Australia lignite (AU) and Hami lignite (HM) are preferred raw materials for DCL. After...
Coal ash fusibility is the key parameter related with ash fouling and slagging in boiler and gasifier. The influences of major compositions in coal ash on fusibility are well known, but the ash rich in sodium and sulfur, such as Zhundong coal, is lack of study. Meanwhile, the sodium and sulfur in Zhundong coal lead to severe slagging and ash deposition during thermal utilization. In order to reveal...
Low-temperature pyrolysis (LTP) and solvent treatment (Sol-T) of Yunnan brown coal were conducted for purpose of comparing their effects on upgrading and hydro-liquefaction. Sol-T is effective in both dewatering and deoxygenation of the brown coal. LTP is also effective in dewatering but less effective in deoxygenation, and more extensive cross-linking occurred during LTP than in Sol-T. Sol-T at mild...
A kind of composite catalytic materials, Metal-POM@MOF-199@MCM-41 (Metal-PMM), were obtained by confining MOF-199 encapsulating metallic Keggin POM into mesoporous MCM-41. The catalyst was designed on the stability and efficiency, which MCM-41 could act as a stable cavy for the heterogeneous metallic POM-based catalyst in the oxidative desulfurization process. The structure characteristics of the...
Since direct coal liquefaction (DCL) was invented, it has been a promising technology for the efficient utilization of coal resources and the mitigation of the oil crisis. Generally, coals are regarded as mixtures composed of organic matter and mineral matter. The mineral matter content and nature of coal is highly variable and has been proved to significantly influence the thermal behavior of coals...
SiO2/Al2O3 (S/A) in the ash content is always regarded as the key factor on ash sintering and slagging in the boiler and gasifier. However, the effect of S/A on ash fusion behavior is not clear for using improper samples and few quantified analysis of fusion process has been conducted. In this work, the effect of S/A has been investigated by ash fusion temperature (AFT) test, thermomechanical analysis...
Co-pyrolysis of lignite with direct coal liquefaction residue (DCLR) is a promising method in the field of clean coal technology. To investigate the influence of DCLR fraction on the physico-chemical structure and combustion reactivity of the co-pyrolysis chars, char samples with different mass fraction of lignite and DCLR were prepared in a quartz tube fixed-bed reactor at 550°C. Then the physico-chemical...
A catalyst system designed by a kind of hybrid material POM@MOF-199@MCM-41 (PMM) was found by a one pot and POM template self-construction of MOF-199 in the pore of MCM-41. This catalyst was exploited to act as a stable heteropolyacid-based one in the direct oxidative desulfurization process with a feedstock of model oil under O2 as oxidant. Based on optimal conditions, the DBT conversion reached...
Low-temperature pyrolysis could effectively recover heavy oil from direct coal liquefaction residue (DCLR), and the derived DCLR char (DCLRCH) could be gasified to compensate hydrogen consumption during liquefaction. The staged processing of DCLR, pyrolysis and gasification, is thought to be a promising method for its high-efficient usage. In the work, DCLR was pyrolyzed under different pyrolysis...
Limestone is widely used in entrained flow gasifiers to improve slag viscosity properties, while viscosity–temperature curve of slag is typical of a crystalline slag when CaO content is above a certain level, of which the viscosity sharply increases when the temperature is lowered below temperature of critical viscosity (TCV). Experiments were conducted on selected slags at about 5wt% Fe2O3 level...
The extraction residue (ER) from Xinghe lignite was subjected to ethanolysis at 300°C and the yield of ethanol-soluble portion (ESP) is 66.8wt% (daf). The ER was characterized by solid-state 13C nuclear magnetic resonance spectrometry (SS 13C NMRS) and X-ray photoelectron spectrometry (XPS), while non-basic and basic heteroatom-containing species in the ESP were analyzed by negative- and positive-ion...
As an important and inevitable component of gasification slag, residual carbon is an internal factor that influences the flow properties of slag. In this study, the effect of residual carbon on slag viscosity was investigated. Viscosity of slag containing graphite was measured at 1350–1680°C under an argon (Ar) atmosphere. The fusibility of ash was examined with thermomechanical analyzer (TMA). X-ray...
Numerical investigations on characteristics of diffusion filtration combustion are conducted in a plane-parallel packed bed. A detailed gas-phase reaction mechanism is used, and mass dispersion in packed bed is also taken into account. Attention is mainly focused on the combustion characteristics and the influencing factors, such as the gas and solid temperature profiles in the burner, the influences...
Entrained flow gasification employs a high temperature, high pressure slagging gasifier, in which slag viscosity plays a key role in determining operating conditions. The effect of cooling rate on viscosity properties were investigated by high temperature rotational viscometer. Viscosities of two slag, which exhibited glassy and crystalline slag behavior, were determined under continuous measurement...
Transformation of pyrite in a demineralized subbituminous coal with various coal particle size distributions (PSD) during pyrolysis was investigated using a thermogravimetric analyzer coupled with mass spectrometer (TGA-MS). The residues from pyrolysis were examined by X-ray diffraction (XRD) and scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (SEM-EDS). It is found...
Direct coal liquefaction residue (DCLR) is a main byproduct in direct coal liquefaction process and its clean and high-efficient utilization is important. If DCLR could be gasified for hydrogen production, it will compensate hydrogen consumption during liquefaction and lower the operation cost, which makes DCLR utilization more promising. We proposed to blend DCLR with low-rank coals to prepare DCLR–coal–water...
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