The pyrolysis behaviors of vitrinite and inertinite from Chinese Pingshuo coal were investigated by using the thermogravimetry coupled with mass spectrometry (TG–MS) and in a fixed bed reactor, respectively. The results showed that inertinite has lower pyrolysis reactivity, lower tar and gas yields, but higher water yield than vitrinite. At 650 °C, the tar and gas yield of vitrinite is 22.4% and 14.4%, respectively, obviously higher than 13.4% and 10.2% of inertinite. The TG–MS analysis also showed much difference of vitrinite and inertinite in gas evolution profile. The ultimate and XRD analyses of chars indicated that the difference in element composition of vitrinite char and inertinite char decreases with the increase of temperature, and have similar element composition and structure characteristic at 650 °C. The total sulfur removal of both vitrinite and inertinite increases with the pyrolysis temperature, and reaches to 60% at 650 °C, but the organic sulfur in inertinite seems more stable than that in vitrinite.

A new process to integrate coal pyrolysis with CO2 reforming of methane over Ni/MgO catalyst was put forward for improving tar yield. And several Chinese coals were used to confirm the validity of the process. The experiments were performed in an atmospheric fixed-bed reactor containing upper catalyst layer and lower coal layer to investigate the effect of pyrolysis temperature, coal properties, Ni loading and reduction temperature of Ni/MgO catalysts on tar, water and char yields and CH4 conversion at fixed conditions of 400 ml/min CH4 flow rate, 1:1 CH4/CO2 ratio, 30 min holding time. The results indicated that higher tar yield can be obtained in the pyrolysis of all four coals investigated when coal pyrolysis was integrated with CO2 reforming of methane. For PS coal, the tar, water and char yield is 33.5, 25.8 and 69.5 wt.%, respectively and the CH4 conversion is 16.8%, at the pyrolysis temperature of 750 °C over 10 wt.% Ni/MgO catalyst reduced at 850 °C. The tar yield is 1.6 and 1.8 times as that in coal pyrolysis under H2 and N2, respectively.

Pyrolysis behaviors of three weakly reductive coals from northwest China and one reductive Pingshuo (PS) coal were investigated in a thermogravimetric analyzer and a fixed-bed reactor. The results show that the pyrolysis behaviors of the weakly reductive coals are obviously different from that of the reductive coal despite their similar elemental composition. Compared with PS coal, the weakly reductive coals exhibit a lower weight loss and a lower rate of weight loss, and the peaks corresponding to the maximum rate of weight loss shift to high temperature. During pyrolysis in a fixed-bed reactor, the conversion and tar and gas yields of all the coals increase with temperature. The weakly reductive coals have lower conversions and tar yields than PS coal in the temperature range investigated, which is accordant with the weight loss in thermogravimetric analysis. The tars from coal pyrolysis were characterized by FT-IR, ultimate analysis, and 1H NMR, and the combustion behavior of chars from different coals was compared on a thermogravimetric analyzer.

Our previous works showed that the tar yield of coal pyrolysis can obviously be improved by integrated CO2 reforming of methane to coal pyrolysis in a fixed-bed reactor consisting of an upper catalyst layer and a lower coal layer. In this work, the effects of catalyst supports (MgO, Al2O3, SiO2, and NaY) and reaction conditions on tar and water yields, CH4 conversion in pyrolysis of Chinese Pingshuo coal, and the carbon deposition on different catalysts were investigated. The results indicated that the catalyst support has an important effect on the integrated process and MgO is the best among the studied supports. A higher tar yield, lower water yield, and lower carbon deposition can be obtained with Ni/MgO as the catalyst. The tar yield increases with the increase of the pyrolysis temperature, holding time, CO2/CH4 ratio, and CH4 flow rate, respectively, while the char yield decreases with an increasing pyrolysis temperature.

Single and multi-stage liquefaction of Shenhua (SH) bituminous coal and re-liquefaction of its liquefaction residue (SHLR) were carried out in an autoclave reactor to investigate the essential approach for promoting oil yield and conversion in SH coal direct liquefaction (SHDL). The multi-stage liquefaction includes pretreatment, keeping the reactor at 250 °C for 40 min before heating up to the reaction temperature, and two-stage liquefaction processes consisting of low temperature stage, 400 °C, and high temperature stage, 460 °C. The results show that the pretreatment has slight effect on oil yield and conversion of SHDL, especially for liquefaction at 460 °C. There is a positive function of two-stage liquefaction in shortening reaction time at high temperature. Increasing ratio of solvent to SHLR can promote the oil yield and abate reaction condition in SHLR re-liquefaction, that is, it can promote the conversion from preasphaltene and asphaltene to oil. The primary factor to inhibit coal liquefaction is the consumption of hydrogen free radical (H·) from solvent or H2 and condensation of free radicals from coal pyrolysis after a period of reaction. So the essential approach for increasing oil yield and conversion of SHDL is to provide enough H· to stabilize the free radicals from coal pyrolysis.

On a semi-continuous apparatus, a weakly reductive Shenfu-Dongsheng (SD) coal and a reductive Pingshuo (PS) coal were non-isothermally extracted with sub- and supercritical water to explore the differences between the two coals. The effect of the temperature on the extract formation rate, conversion, and product composition under different pressures was investigated. The extraction results of two coal samples indicate that the extract formation rate has a maximum in the studied temperature range between room temperature and 500 °C. The temperature corresponding to the maximum extract formation rate, changing with the pressure, is between 390 and 410 °C. The gas yield, extract yield, and conversion of two coals increase with the increasing pressure. In comparison to PS coal, SD coal has a low temperature corresponding to the maximum extract formation rate under the same pressure. Both coals have a main fraction of asphaltene, but SD coal has a higher fraction of oil than PS coal. The main gas components are CO2, CH4, and H2. The gas from PS coal has a higher CH4 content and lower CO2 content than that from SD coal. The analysis results of the extraction residue indicated that SD coal has a low residue yield and the residue shows a large surface area and small average pore diameter compared to PS coal.

The aim of this research is to understand the major function of iron-based catalysts on direct coal liquefaction (DCL). Pyrolysis and direct liquefaction of Shenhua bituminous coal were carried out to investigate the effect of three solvents (wash-oil from coal-tar, cycle-oil from coal liquefaction, and tetralin) in a N2 or a H2 atmosphere and with or without catalyst. The hydrogen content in the solvent and liquid product and the H2 consumption for every run were calculated to understand the hydrogen transfer approach in DCL. The results showed that the iron-based catalyst promotes the coal pyrolysis, and the dominating function of the catalyst in DCL is to promote the formation of activated hydrogen and to accelerate the secondary distribution of H in the reaction system including the gas, liquid, and solid phases. The major transfer approach of the activated hydrogen is from molecular hydrogen to solvent and then from solvent to coal, and the solvent takes on the role of a “bridge” in the hydrogen transfer approach.

Direct liquefaction of Shenhua bituminous coal was carried out in a 500 ml autoclave with iron catalyst and coal liquefaction cycle-oil as solvent at initial hydrogen of 8.0 MPa, residence time of 0–90 min. To investigate the liquefaction kinetics, a model for heating-up and isothermal stages was developed to estimate the rate constants of both stages. In the model, the coal was divided into three parts, easy reactive part, hard reactive part and unreactive part, and four kinetic constants were used to describe the reaction mechanism. The results showed that the model is valid for both heating-up and isothermal stages of liquefaction perfectly. The rate-controlled process for coal liquefaction is the reaction of preasphaltene plus asphaltene (PAA) to oil plus gas (O + G). The upper-limiting conversion of isothermal stage was estimated by the kinetic calculation.

An asymmetric carbon membrane was prepared by coating alcohol solution of novolac phenol–formaldehyde resin containing a little hexamine on a porous resin support from the same material. After drying in air for two days at room temperature, the coated support was heated at 150 °C for 1 h in air (heating rate: 0.5 °C/min) and then carbonized at 800 °C (heating rate: 0.5 °C/min) in Ar atmosphere. The support and the membrane layer were carbonized simultaneously. The coating–pyrolysis cycle only needed one time. SEM photographs showed the carbon membrane had an asymmetric structure formed by a dense skin layer with a thickness of around 35 μm and a porous substrate. Pure gases of different molecular size (H2, CO2, O2, N2 and CH4) were used to test the carbon membrane permeance property. The membrane has a good selectivity for H2/N2 and H2/CH4 with H2 permeance of 4.05 × 10−6 cm3 cm−2 s−1 cmHg−1. The permeance is independent of pressure. The results indicate that the gases transport through the membrane according to molecular sieve mechanism.

Carbon molecular sieve membrane (CMSM) was prepared by pyrolysis of phenol formaldehyde novolac resin (PFNR) blended with poly(ethylene glycol) (PEG). The carbon structures and the gas permeation properties of the CMSM pyrolyzed at 800 °C were characterized in terms of the different weight ratio of PEG to PFNR and different molecular weight of PEG. The thermogravimetric analysis indicated that the copyrolysis in the PEG/PFNR appears at temperature of 400 °C. The nitrogen adsorption isotherm of the CMSM showed that the weight ratio of PEG/PFNR and molecular weight of PEG significantly affect the average pore volume of the CMSM. These results confirmed that PEG is a significant pore-forming agent in the CMSM for the micropores forming during pyrolysis, which will increase the pathways of diffusion for the transport of gas molecules through the CMSM. The CMSM prepared exhibits an enhanced H2 and O2 gas permeability from 2.4 × 10−9 and 6.4 × 10−11 to 8.0 × 10−9 and 1.8 × 10−10 mol m−2 s−1 Pa−1, and the H2/N2 and O2/N2 selectivity of the CMSM derived from PEG/PFNR blends decreases from 471.3 and 12.8 to a minimum of 284.6 and 6.2, respectively, with addition of PEG with molecular weight of 10,000 to PFNR in weight ratio of 0.05.

Carbon aerogels have been prepared through a polycondensation of cresol (Cm) with formaldehyde (F) and an ambient pressure drying followed by carbonization at 900 °C. Modification of the porous structures of the carbon aerogel can be achieved by CO2 activation at various temperatures (800, 850, 900 °C) for 1–3 h. This process could be considered as an alternative economic route to the classic RF gels synthesis. The obtained carbon aerogels have been attempted as electrode materials in electric double-layer capacitors. The relevant electrochemical behaviors were characterized by constant current charge–discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy in an electrolyte of 30% KOH aqueous solution. The results indicate that a mass specific capacitance of up to 78 F g−1 for the non-activated aerogel can be obtained at current density 1 mA cm−2. CO2 activation can effectively improve the specific capacitance of the carbon aerogel. After CO2 activation performed at 900 °C for 2 h, the specific capacitance increases to 146 F g−1 at the same current. Only a slight decrease in capacitance, from 146 to 131 F g−1, was observed when the current density increases from 1 to 20 mA cm−2, indicating a stable electrochemical property of carbon aerogel electrodes in 30% KOH aqueous electrolyte with various currents.

Chinese Yima coal and its HCl/HF and HCl/HF/HNO3 treated samples were pyrolyzed in a fixed bed reactor under a pressure of 2 MPa. The effect of mineral on organic and pyrite sulfur transformation was investigated along with the effect of decomposition of pyrite on organic sulfur removal during pyrolysis. The results showed that the inherent mineral in coal has little effect on the decomposition of pyrite. The problems to hinder sulfur removal from coal during pyrolysis mainly include following three aspects: (I) large proportion of sulfide was produced from alkaline mineral matter in coal reacting with sulfur containing gas; (II) pyrite sulfur transformed into organic sulfur; (III) iron sulfide produced by decomposition of pyrite, which is more difficult to decompose at low temperature.

Pyrolysis experiments of six differently ranked Chinese coals and one German coal were carried out systematically at ambient pressure. The effect of different pyrolysis conditions, including coal properties, temperature, drying of coal, on the product distribution and the behavior of sulfur in coal were investigated. The results indicated that, besides coal properties, temperature is the most important factor which affect the product distribution of pyrolysis. CO and CO2 yields in gas product are related to the oxygen content in the coal sample. Except for the sample of Datong (DT) coal, the CO and CO2 yield increases linearly with the increase in O/C atomic ratio of coal; sulfur-containing gas (H2S and COS) yield depends directly on sulfur content in the coal. With the increase in total sulfur content, pyrite sulfur content or organic sulfur content of coal, the sulfur containing gas increases substantially. Sulfur removal during coal pyrolysis at different conditions varies from 15% to 40% depending on coal sample, pyrolysis temperature and time. For most coal samples, the sulfur content in char is less than that in its original sample, but some exception was also found. X-ray photoelectron spectroscopy (XPS) analyses suggest that difference in sulfur removal may be partly attributed to the difference in sulfur contents in the bulk and on the surface for different coals.

Two Chinese coals, Shenfu subbituminous coal and Huolingele lignite, were used to investigate the effect of mineral matter in coal on reactivity and kinetic characteristics of coal pyrolysis. The experiments were carried out by using thermogravimetry to check the pyrolysis behavior of raw coal, HCl/HF demineralized coal and demineralized coal with inorganic matter (CaO, K2CO3 and Al2O3) added, respectively. The results showed that inherent mineral in coal had no evident effect on the reactivity and kinetics of coal pyrolysis. CaO, K2CO3 and Al2O3 all had a catalytic effect on the reactivity of coal pyrolysis, their effects were closely related to temperature region and coal types. The pyrolysis process of all the samples studied can be described by three independent first order kinetic model. Addition of inorganic matter the activation energy decreased and the characteristic temperature of coal changed.

Two kinds of residues, obtained from the extraction of a weakly reductive coal, Shenfu-Dongsheng coal (SD), and a reductive coal, Pingshuo coal (PS), with sub- and supercritical water on a semi-continuous apparatus, were characterized by calorific value analysis and X-ray photoelectron spectroscopy analysis, and the combustion behaviors of residues were investigated by thermogravimetric analysis. The results show that the residues have higher calorific value than raw coal samples, and SD residue has higher calorific value than PS residue. C—C, C—O, and pyridinic nitrogen and pyrrolic nitrogen are the dominant form of C, O, and N on the surface of raw coal samples and their extraction residues. The combustion behaviors of extraction residues show that the SD residue is more reactive and more easily burned than PS residue.

The desulfurization of model gasoline containing 600 ppmw thiophene or dibenzothiophene (DBT) by selective adsorption over Ag+ exchanged mesoporous material Al-MSU-S was studied in a fixed adsorbent bed at ambient temperature and pressure. The results showed that the sulfur capacity increased with Al content incorporated in the silicate framework and Ag+ exchange can effectively improve the desulfurization performance. The best adsorbent, Ag+/20%Al-MSU-S, has adsorption capacity of 5 or 20 ml model gasoline containing thiophene or DBT per gram adsorbent, respectively, before the detection limit in our experiments, as a result of π-complexation. The adsorbent can be regenerated more than six times by simple calcination in air at 350 °C without obvious losing the sulfur adsorption capacity.

An improved dealumination method for adjusting the acidity of HZSM-5 was developed by utilizing the self-adsorbed water in HZSM-5. The parent and treated HZSM-5 were characterized by XRD, FT-IR, 27Al MAS NMR, N2 adsorption, XRF and NH3-TPD. The results showed that HZSM-5 can be dealuminated when treated at above 400 °C. About 80% acidic amount was removed from parent HZSM-5 with 8% adsorbed water and more Lewis acid sites were produced after treated at 500 °C. It is thought that the dealumination was mainly caused by its self-adsorbed water. The comparisons of the acidity in dealuminated HZSM-5 by traditionally steaming and improved methods indicated that the latter was more effective in decreasing the acidity and weakening acid strength, and more environmentally benign and timesaving. The method is also applicable to adjust acidity of other zeolites, such as HY, Hβ.