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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...
Catalytic steam gasification of an Inner Mongolia lignite for hydrogen-rich gas production was investigated in a decoupled triple bed reaction system with olivine and Ni/olivine as both solid heat carrier and in-situ tar cracking/reforming catalyst. In the system, tar cracking/reforming, pyrolysis/gasification, and char combustion reactions are decoupled into three separated reactors, i.e. a reformer,...
Coal is an important fossil energy. In order to improve its use efficiency, the study of its complex structure has drawn much attention all over the world. Since 1942, lots of molecular level models of coal have been proposed. However, they cannot reflect the yield distribution of benzene carboxylic acids (BCAs) that are generated from coal by oxidation. In this work, the organic matter structure...
The process, where brown coal is extruded after mechanical kneading and then allowed to air dry slowly to form a product known as ‘densified coal’, was applied to reduce the moisture content of two Victorian brown coals. NaOH at different concentrations (0–1.5M) was used as an additive in the kneading step. The spontaneous combustion propensity of the densified products was evaluated and compared...
Nitrogen oxide generated by coal oxidation accentuates the greenhouse effect and makes the environment uninhabitable. In this work, two models of lignite were built in order to study the pyrolysis and oxidation processes and the influence of O2 on its nitrogen-transfer mechanism at high temperatures. The structural units of the two models are taken from the lignite model provided by Wolfrum. Reactive...
Phosphogypsum (PG) is a by-product in the phosphate fertilizer industry, and low rank coal-lignite has high moisture which seriously influence its direct use. As a promising raw material for chemical industry, syngas can be obtained through a properly designed lignite Chemical Looping Gasification (CLG) of PG oxygen carrier. The understanding of the reaction mechanism has been developed, while optimal...
Conversion of coal into dedicated hydrocarbons has been developed in the beginning of the last century and is still practiced in areas of the world with scarcity or insecure oil and gas supply.Given the need for carbon in chemistry, possible political disruptions in oil and gas producing regions and the rise of renewable energy, lignite, as a secure domestic raw material, can serve as a chemical feedstock...
Zhaotong lignite (ZL) was subjected to ethanolysis at 305°C to afford soluble portion 1 (SP1) and residue 1 (R1). R1 was ethanolyzed with NaOH at 305°C to obtain soluble portion 2 (SP2) and residue 2 (R2). SP2 was separated to extracts 1–3 (E1-E3) by sequential extraction with petroleum ether, carbon disulfide, and dichloromethane. SP1 and E1-E3 were analyzed with a gas chromatograph/mass spectrometer,...
The interactions in the “lignite-surfactant” system were studied with the aim of disclosing the mechanism of the decrease in hydrophilicity of lignite using cetyltrimethylammonium bromide (CTAB). The inhibiting efficiency in the hydrophilicity of lignite by CTAB was studied by measuring the wetting heat using a Calvet calorimeter. The adsorption of CTAB to organic content and mineral matter was analyzed,...
Co-combustion of dried waste activated sludge (WAS) and lignite was conducted in a horizontal tube furnace system. The mineral transformation and emission behaviors of Cd, Cr, Ni, Pb, and Zn during combustion were examined. The above heavy metals (HMs) were selected because they are more abundant in WAS than in lignite. In the combustion condition of 1000°C–21% O2–30min, the minerals in lignite ash...
Lignite is rich in oxygen-containing species (OCSs) and able to load Ni via ion exchange to prepare Ni/C catalyst. However, the OCSs usually exists in the form of organic salts, which can reduce the capacity of Ni ion exchange. In this paper, Shengli lignite (SL) was treated with HCl and HCl/HF to selectively remove the organic salts and insoluble minerals, respectively, and the modified lignite was...
Carboxylic acids (CAs) are important chemicals widely used in industrial manufacturing. They can be produced with high yields from O2 oxidation of lignite and the process is regarded promising in the future. However, current methods for the process consume a large amount of mineral alkali and acids, or involve catalysts that are harmful to environment and human beings, and require high temperatures...
Production of carboxylic acids (including 12 types of benzene carboxylic acids (BCAs) and small-molecule fatty acids) from lignite via oxidation has been widely studied, but few studies addressed the relationship between distribution of BCAs and structure of lignite. This work studies alkali-oxygen oxidation of Xiaolongtan lignite and distributions of BCAs with 13C NMR as well as the relationship...
The molecular structure model of the Shengli lignite was determined via TG-GC/MS for the analysis of the pyrolysis products’ structure and contents, in combination with ultimate analysis and FTIR for the determination of its structure parameters. Then the model was constructed by hand referring to references, optimized and revised on the basis of quantum chemistry by semi-empirical and the second...
The High-Temperature Winkler process (HTWTM), which has been developed by the companies Rheinbraun and Uhde in the mid-70s of the 20th century, is an evolution of the Winkler-fluidized bed gasification process. The gasifier is divided into two zones, the bubbling fluidized bed operated at temperatures well below the ash softening point, and the freeboard operated at higher temperatures in order to...
To investigate the molecular composition of soluble organic species in Baiyinhua lignite (BL) and their evolution profiles during pyrolysis, BL was firstly pyrolyzed in a fixed-bed reactor, affording gaseous products, tars and chars, then BL and its chars were thermally dissolved in supercritical methanol affording soluble portions (SPs). The composition and structural characteristics of the SPs and...
The main objective of this work was to investigate the ignition behavior of two Turkish biomass residues (almond shell and olive residue) and two Turkish lignite coals (Tunçbilek and Soma) at low and high heating rates. The low heating rate experiments (20K/min) were performed in a thermogravimetric analyzer (TGA) coupled with a differential scanning calorimetry (DSC) analyzer, while the high heating...
HulunBuir lignite pyrolysis at low temperatures with different coal particle sizes, and different heating modes were studied on a fixed-bed reactor in order to investigate the oxygen evolution characteristics. The results show that pyrolysis temperature heavily influences the oxygen evolution. Almost 70.69wt% of oxygen in lignite transferred into volatile products at 700°C. With an increase of temperature,...
This research aims to discuss complex economics of lignite-based energy projects with respect to risk and uncertainty, optimisation, sustainable land use and the importance of lignite as fuel that may be expressed in situ as a deposit of energy. The sensitivity analyses and Monte Carlo simulations performed in this article include estimated land acquisition costs, geostatistics, 3D deposit block modelling,...
The gasification of lignite with a moisture content of 5–10% was carried out by GSP pulverized coal gasification process(GSPPCP). An air separation unit was set up to make use of oxygen and nitrogen during lignite drying process. This was a potential approach to utilize the mixture of oxygen and moisture in lignite as a feedstock for gasification agent. In this paper, the physico-chemical properties...
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