Batch methanogenic fermentation experiments of wastewater from a brown coal low-temperature coke plant

Coke plant effluents with high contents of organic compounds are mainly treated by biological aerobic fermentation after physical pre-treatment. In this study, a brown coal condensate wastewater from a low temperature coking process was fermented under methanogenic conditions in discontinuous experiments. By this fermentation, acetate, propionate, and the main polyphenolic compounds （catechol, resorcinol and hydroquinone） were degraded to a level below the detection limit. The COD was reduced by 72% with a residual concentration of 2.1 g/L. This anaerobic fermented wastewater had a residual BOD5 of 0.66 g/L and 2.2 L CH4 were formed per litre of wastewater. An abiotic pre-treatment for this wastewater with air had a negative effect on the COD reduction and decrease of colour on the methanogenic fermentation due to the autoxidation of polyphenolic compounds to humic-like compounds. This study showed that methanogenic fermentations in the treatment sequence of brown coal coking wastewaters could reduce energy consumption for aeration in further treatment processes and had the potential for a better effluent quality due to a less formation of recalcitrant humic-like compounds.

Gasification kinetic modelling of Victorian brown coal chars and validity for entrained flow gasification in CO_(2)

The gasification kinetic modelling of two Victorian brown coal(Yallourn and Maddingley)chars and the validity for entrained flow gasification were investigated in this study.The study was conducted in a thermogravimetric analyzer(TGA)at 750–1100℃,30%–90%CO_(2)concentration using different char particle sizes within 20–106 mm.It was found that random pore model and modified volumetric model are applicable for TGA results,but volumetric model and grain model are not.The effect of particle size under106 mm on gasification rate is very limited.Activation energies of Maddingley char and Yallourn char in CO_(2)gasification are 219–220 and 197–208 k J/mol,respectively.The pre-exponential factors are in the same order of magnitude,and they increased as particle size decreased.A mathematical model was developed to predict carbon conversion over time for entrained flow gasification of Victorian brown coal chars at 1000–1400℃.

An Experimental Study on the Production of Fulvic Acid from Brown Coal Using N-Mn-TiO_2 as a Catalyst and H_2O_2 or HNO_3 as an Oxidizer

[Objective] The study aimed to extract fulvic acid from brown coal using N-Mn-TiO2 as a catalyst and H2O2 or HNO3 as an oxidizer. [Method] The effects of catalyst N-Mn-TiO2 on the yield and structure of fuMc acid were studied, and the content of functional groups in fulvic acid was analyzed qualitatively and quantitatively. [ Reselt] Two catalysts could improved the yield of fulvic acid, that is, catalyst 1 （N： Mn： 13 = 16： 0.001：1, roasting temperature was 400 ℃） and catalyst 2 （N： Mn： Ti = 16： 0.001：1, roasting temperature was 100 ℃） increased OFA yield by 10.69% and 32.17% and NFA by 8.61% and 7.49% respectively. After the addition of catalysts, the content of total acid radicals in OFA changed little, and carboxyi content increased slightly, but phenolic hydroxyl content decreased. When HNO3 was used as an oxidizer, the content of total acid radicals and phenolic hydroxyl in NFA decreased. In addition, the structure of OFA was different from that of NFA. [Condusion] The research could provide scientific references for the development and application of brown coal in future.

Experimental Study on the Method of Extracting Humic Acids from Brown Coal Using Hydrogen Peroxide

[ Objective l The study aimed to discuss the optimal conditions of extracting humic acids from brown coal using hydrogen peroxide （H202）. [ Method] Fulvic acid （FA） was prepared through oxidizing the brown coal from Qujing City, Yunnan Province using H202, and humic acids were extracted from the original brown coal and its residues respectively, then the dominate constituents of humic acids were obtained by using pH grading method, finally their chemical composition of humid acids was characterized by Fourier transform infrared spectrometry and func- tional group content analysis. [Result] The mass ratio of the brown coal and oxidant affected the yield of FA most obviously, followed by oxidization temperature and duration, while oxidant concentration had no obvious effect. The optimum conditions were determined as follows： coal-oxidant ratio was 1 ： 0.60, oxidization temperature was 45 ℃, oxidization duration was 210 min, and the concentration of hydrogen peroxide was 20%. Under the conditions, the yield of FA was up to 20.40%. Analysis of component properties indicated that the content of carboxyl and total acidic groups in FA improved obviously under the optimum conditions, and the content of active functional groups in OHA was higher than that of HA, while the domi- nate constituents of OHA needed higher pH during precipitation compared with those of HA. [ Conclusion] The research could provide a new method to prepare good humic acids using brown coal,

Future of Renewable Resources in an Area Burdened by Brown Coal Mining

This contribution is focused on a possible utilization of renewable energy resources in the Podkrušnohoří?region (Chmomutov, Most, Teplice, ústí nad Labem districts) in the northern part of the Czech Republic after the end of brown coal mining in 2055. Results of the research describe current share of renewable energy resources (solar, wind, water, biogas) in the model area, and a future energy potential in order to ensure sustainable development of an anthropogenically burdened region. Aim of this contribution is to determine, which renewable energy resources would be the most suitable for energy production after the end of brown coal mining. It also describes current and possible use of geothermal power as there are registered heat flow anomalies in the area.

Preparation of magnetically separable mesoporous activated carbons from brown coal with Fe3O4

Magnetically separable mesoporous activated carbon was prepared from brown coal in the presence of Fe3O4 as a bi-functional additive.Magnetic activated carbon(MAC)was characterized by lowtemperature nitrogen adsorption,scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and vibrating sample magnetometry(VSM).The evolution behaviors and transition mechanism of Fe3O4 during the preparation of MAC were investigated.The results show that prepared MAC with 6 wt%Fe3O4 addition having a specific surface area and mesopore ratio of 370 m^2·g^-1 and 55.7%,which meet the requirements of adsorption application and magnetic recovery.Highly dispersed iron-containing aggregates with the size of 0.1 lm in the MAC were observed.During the preparation of MAC,Fe3O4 could enhance the escape of volatiles during the carbonization.Fe3O4 could also accelerate burning off the carbon wall during activation,which leads to enlarging micropore size,then resulting in the generation of mesopore and macropore.As a result,a part of Fe3O4 converted into FeO,FeOOH,a-Fe,c-Fe,Fe2SiO4 and compound of Aluminum-iron-silicon.The prepared activated carbon,which was magnetized by both of residual Fe3O4,reduced a-Fe and c-Fe,can be easily separated from the original solution by external magnetic field.

Late Cretaceous-Paleogene Palynostratigraphy from the Arkhara-Boguchan Brown Coal Mine of Zeya-Bureya Depression, Russia

A well-preserved Late Cretaceous-Paleogene palynological flora from the middle member of the Tsagajan Formation and the upper member of the Tsagajan Formation including the Kivda Beds is reported for the first time from the Arkhara-Boguchan brown coal mine, southeastern part of the Zeya-Bureya Basin. Four palynocomplexes were established for the Cretaceous-Tertiary transition. The climate and phytocoenoses were also analyzed,based on the detailed palynological data. The results are coincident with those of mega-flora studied by Akhmetiev et al. (2002).

Stratigraphy of southeastern flanks of Raichikhinsk brown coal field (Zeya-Bureya sedimentary basin)

The results of the palynologic and paleobotanic analyses have allowed determining the Paleocene (including Danian) and Eocene deposits in the series of coal-bearing sediments of southeastern flanks of the Raichikhinsk brown coal field. Their age was corroborated by the palynologic and paleobotanic data. The detailed biostartigraphic data were obtained in the area"Pioneer"for the first time. The coal-bearing strata were correlated with those from the sections of the Arkhara-Boguchan brown coal field and the stratotype of the Tsagajan Formation of the Bureya Belogor’ye.

STRUCTURAL ORIGIN OF THE FAULTED BROWN COAL BASIN IN YUNNAN, CHINA──The role of strike-sliping in basin formation and inversion of Xianfeng coal basin

Based on the analysises of regional structural setting, basin formation and deformation, this paper demonstrates that the Xianfeng basin has been formed and inverted under the strike-slip regime. The article is a partial result of the whole research.

Utilization of fruit waste for H_(2)-rich syngas production via steam co-gasification with brown coal

In this work,to efficiently utilize waste fruit and low-rank coal for the hydrogen(H_(2))-rich syngas production,steam co-gasification of banana peel(BP)and brown coal(BC)was studied in a fixed-bed reactor.The results showed that the gasification rate of BC was highly enhanced after mixing it with BP and the obvious synergistic effect was observed in all investigated three mixing weight ratios(i.e.,1:1,1:4,4:1),resulting in a higher carbon conversion as well as a H_(2)-rich gas production yield for the co-gasification.However,the extent of promotion by synergistic effect was affected by the reaction temperature,mixing ratio,and steam amount.It was found that the high potassium(K)species content in the BP provided the catalytic effect not only on water-gas shift reaction but also on tar reforming/cracking,thereby enhancing the gasification of BC.In addition,it is confirmed that steam should be an important factor to promote the synergistic effect and H_(2)-rich gas production.

Discovery and implication of Late Pleistocene soft brown coal from Tengchong Basin, Western Yunnan

The Tengchong Basin, aboat 35 km^2 in area, is a dammed-by-lava type of theintermoniane basin with peat and soft brown coal. The sedimentation in the basin startedbefore 380 ka B. P., and the maximum thickness of the strata is about 250 m, in which

POLYCYCLIC AROMATIC HYDROCARBONS EXTRACTED FROM THE HUANGXIAN BROWN COAL

The various components that make up the PAH fraction extracted from the Huangxian brown coal have been studied using gas chromatograph-mass spectrometry (GC-MS). 56 aromatic compounds representing 11 classes which range from 2 to 5 rings have been detected in the sample. Among these identified compounds, aromatic terpanes account for 94%. The compounds are strongly associated with biological precursors.

内在矿物质对褐煤加氢热解过程中氮迁移的影响

阐明内在矿物质对褐煤加氢热解过程中氮迁移的影响对建立褐煤梯级利用过程中含氮物质污染控制方法,实现褐煤的清洁高效利用具有十分重要的指导意义。研究采用固定床反应器进行胜利褐煤加氢热解试验,考察0.1~3 MPa下内在矿物质对煤中氮向热解产物NH_(3)、HCN、N_(2)、焦油氮和半焦氮中迁移的影响以及半焦中氮官能团生成的影响。分别采用紫外分光光度计、气相色谱仪和元素分析仪分析气相中的NH_(3)、HCN、N_(2)以及焦油氮和半焦氮,采用X光电子能谱仪(XPS)表征半焦中的氮官能团。结果表明:胜利褐煤加氢热解过程中,内在矿物质催化煤中氮向NH_(3)和N_(2)迁移;内在矿物质对煤中氮向HCN迁移的影响受热解压力影响,压力为0.1 MPa时,内在矿物质明显阻碍煤中氮向HCN迁移,而压力为1~3 MPa时,内在矿物质基本不影响煤中氮向HCN迁移;内在矿物质阻碍煤中氮向半焦氮和焦油氮迁移;这是由于加氢热解过程中,内在矿物质降低煤热解反应的活化能,致使更多的自由基攻击煤中的含氮杂环,使较多的含氮杂环分解转化为了NH_(3)、N_(2)和HCN;热解反应活化能的降低促进了挥发分生成的增加,延长了挥发分从反应器中析出的时间,加强了挥发分的二次反应,进而促使挥发分中HCN和焦油氮发生二次反应生成NH_(3)。半焦中存在的内在矿物质提高了新生半焦的反应性,加速了半焦与吸附在半焦上的H的反应,促进新生半焦二次反应生成NH_(3)和N_(2)。内在矿物质促进热解半焦中吡啶型氮的生成而抑制半焦中季氮的生成。内在矿物质对褐煤加氢热解过程中氮迁移影响的研究结果将为褐煤的清洁高效利用技术的发展提供基础数据和技术支撑。

基于Hoek-Brown参数确定方法的多煤层开采工作面矿压显现规律模拟研究

结合宁东矿区任家庄矿的生产实例,利用基于Hoek-Brown强度准则确定煤、岩体力学参数的方法,运用FLAC3D软件模拟分析了任家庄矿3号和5号煤层开采中的矿压显现规律,并根据现场工作面巷道围岩应力和表面收敛监测结果,对比分析了数值模拟结果的准确性。研究发现:基于Hoek-Brown经验强度准则所确定的煤、岩体力学参数与标准煤岩样的实验室测定值有明显差异,两者间并非简单折减关系,而与岩体结构特点、完整岩石强度和开挖影响等因素有关。现场多煤层开采中矿压显现规律的实测与数值模拟结果的比对,进一步验证了基于Hoek-Brown准则确定煤、岩体力学参数的有效性和合理性。

基于Hoek-Brown准则的深部煤层钻井坍塌压力弹塑性分析

利用三轴压缩实验确定了沁水盆地平定区块深部煤岩在高围压条件下的弹塑性特征。以Hoek-Brown准则为极限平衡条件,提出了基于工程允许塑性区半径的深部煤层井眼坍塌压力弹塑性计算方法,得到控制深部煤层井壁坍塌的主要参数:煤岩地质强度指标GSI值、非均匀地应力系数及工程允许塑性区半径。以平定区块PD-095井为例,分析了深部煤层坍塌压力弹塑性结果与弹性结果的差别,讨论了坍塌压力弹塑性结果随影响因素的变化规律。结果表明,当工程允许塑性区半径为井眼半径的1.5倍时,PD-095井坍塌压力弹塑性结果较Hoek-Brown准则、Mohr-Cou-lomb准则弹性结果分别降低6.52%,4.66%;随着工程允许塑性区半径的增大、地应力非均匀性的降低,井眼坍塌压力下降;坍塌压力与地质强度指标GSI值呈负乘幂函数关系。

The Diagenesis of Plant Lipids during the Formation of the Krepoljin Coal Basin(Serbia)—Using Multivariate Statistical Analysis in the Saturated Biomarkers

The composition of the saturated hydrocarbon fraction of soluble organic matter （bitumen） from the Krepoljin brown coal basin （East Serbia） of Miocene age was investigated. The Krepoljin basin is especially interesting from a geochemical point of view. Namely, by the end of Tertiary Period, the basin was covered by powerful Mesozoic formations of great possibilities, the bedding became hermetically enclosed and protected from subsequent external influences. The nature of early diagenetic processes in the environment with abundant accumulation of organic substance is defined by the molecular content of bitumen through the connections of molecular structures to potential precursors in paleoplant phylla, as well as by the degree of their diagenetic transformations. The hierarchy of parameters based on molecules of saturated hydrocarbons was determined by applying the principal component analysis to the soluble organic matter. The most significant, most ＂loadings＂ values of component CI, are the plant types such as precursors or participants in early diagenetic transformations of steranes Cs27-algal precursor material, Cs28-moulds, Cs29-higher land and water plants; resinous from the group of higher plant gymnosperms （G）; also triterpanes a and β-amirindicotyledonous angiosperms （A） and bacterial and/or terrestrial plants population represented by hopanes/moretanes; as well as the parameters which describe the degree of diagenetic/maturation transformation of precursor biomass, and based on next reactions： （1） shifting of methyl group, influenced by the inorganic sediment constitutents, sterane-rearranged steranes, （2） isomerization in the ring system, ααα→βββ C29 sterane as well as （3） isomerization on chiral center of the side chain sequence R→S C29 sterane S/（S＋R）. Additionally, a pyrite-derived inhibitory effect on the rearrangment of C29 steranes must be taken into account, but not on triterpanes reaction. Non- appearance of statistically important correlations, before all with maturational depended parameters, and after all also with source indicators contributies to the affirmation of the newly-suggested parameter α-Phyllocladane/S27 as the real source biomarker of coal. Indicators derived from the distribution and abundance of n-alkanes and isoprenoid alkanes are of less significance in hierarchy of parameters.

伊敏褐煤腐植酸结构特征及其分子模型构建

从褐煤中提取腐植酸对于实现褐煤的清洁高效利用具有重要的意义,而探究蒙东地区褐煤腐植酸结构并构建相应的分子模型对于该地区褐煤应用具有广泛的指导作用。采用碱溶酸析法提取蒙东伊敏褐煤的腐植酸,通过采用X射线衍射、^(13)C核磁共振以及X射线光电子能谱等方法对腐植酸的结构特征进行全面表征。结果表明:伊敏褐煤腐植酸中的芳香结构是基础,而脂肪结构主要以交联键以及侧链形式存在;褐煤腐植酸中的芳香团簇尺寸较小,芳香层间距相对较大,且呈现无序排列。根据结构表征相关参数,重构了具有代表性的中国蒙东伊敏褐煤腐植酸分子模型。所构建的伊敏褐煤腐植酸分子结构模型计算数据与实验数据大体吻合,能够充分反映伊敏褐煤腐植酸的化学结构特点。模型中芳香碳结构主要以苯、萘环的形式呈现,少量以菲环形式的存在;脂肪碳主要以较短的侧链和脂肪环形式存在,起到连接芳香基本结构单元的作用。氧元素主要以羧基和酯等O—C=O形式存在,同时还包括一定量的酮、醛、醌、酚、醇以及醚氧,其中羰基C O和醚氧具有交联作用。氮元素则主要以吡咯环的形式存在,并伴有少量的吡啶环和季氮。与西南地区云南褐煤腐植酸结构相比,伊敏褐煤中的芳香碳含量更高且吡咯含氮官能团所占比例也更大,并呈现出一定的地区差异性。

基于Hoek-Brown准则的节理扩展煤层破碎分级方法

考虑地应力作用下煤层节理扩展特性对煤层破碎的影响,给出了煤层节理扩展的判别方法。应用小波神经网络方法和逐级加载算法,联合反演分析节理扩展煤层应力场,获取煤岩单点最大、最小主应力,并结合霍克-布朗准则提出煤层破碎分级定量研究方法。依据煤层破碎系数大小和能量法判据将煤层破碎程度划分为A、B、C、D四个等级,并确定煤岩破碎分级标准。应用本文提出的煤岩破碎分级方法和标准,对沁水盆地晋城区块煤层破碎分布规律进行预测,结果表明:晋城区块南部的阳城、町店、樊庄、潘庄等地区煤层破碎严重(A级),而区块的西北部煤层破碎程度最轻(D级)。理论结果与现场实测的煤层地质资料一致,验证了本方法的预测结果。

Effects of calcium on the evolution of nitrogen during pyrolysis of a typical low rank coal

This study aims to investigate the effects of calcium on the migration of nitrogen in coal(coal-N)to N-containing gas species,particularly,NH3 and HCN(volatile-N)in volatiles,as well as the chemical transformation of the N in char during coal pyrolysis under different temperatures.The pyrolysis experiments of Shengli brown coal and its derived coal samples loaded with different contents of calcium were conducted under 600–800°C in a novel fluidized bed reactor.The experimental results showed that during coal pyrolysis,the generation of NH3 is mainly derived from secondary reactions among volatiles,tar and char with the catalytic effect of mineral matter,especially calcium in coal.Increasing pyrolysis temperature from 600 to 800°C could enhance the release of N in coal to volatiles.Meanwhile,the increased pyrolysis temperature could also inhibit the generation of NH3 while facilitating the formation of HCN.The release of HCN is more sensitive to pyrolysis temperatures.Specifically,under higher pyrolysis temperatures,more N-containing structures in coal would become thermally unstable and crack into HCN;On the other hand,higher pyrolysis temperature could also enhance the decomposition of N in coal to N-containing species in tar or N2,thus reducing the release of HCN and NH3.Nitrogen in tar could either undergo secondary decomposition reactions,generating NH3,HCN,N2 and other N-containing species in gas phase,or experience condensation polymerization by forming macromolecular structure and be retained in char at high pyrolysis temperatures.Calcium could significantly restrain the release of N from coal,thus reducing the yields of NH3 and HCN.During coal pyrolysis,calcium catalytically enhances the fracture and combination of chemical bonds,generating abundant free radicals.These free radicals could continuously attack N-containing structures and consequently release the N-containing gaseous products,such as NH3,HCN,N2 etc.,resulting in the decrease of N in char.Calcium also plays important roles in nitrogen transformation in char during coal pyrolysis by catalytically intensifying the transformation of N in char from pyridinic nitrogen(N-6)and pyrrolic nitrogen(N-5)to quaternary type nitrogen(N-Q)during coal pyrolysis.