Synergistic CO_(2) mineralization using coal fly ash and red mud as a composite system

CO_(2) mineralization plays a critical role in the storage and utilization of CO_(2).Coal fly ash(CFA)and red mud(RM)are widely utilized as CO_(2) mineralizers.However,the inert calcium species in CFA limit its carbonation capacity,meanwhile the substantial Ca^(2+)releasing of RM is hindered by a covering layer of calcium carbonate.In this study,CO_(2) mineralization in a composite system of CFA and RM was investigated to enhance the carbonation capacity.Multiple analyzers were employed to characterize the raw materials and resulting mineralization products.The results demonstrated that a synergistic effect existed in the composite system of CFA and RM,resulting in improving CO_(2) mineralization rate and efficiency.The produced calcium carbonate was ectopically attached the surface of CFA in the composite system,thus slowing down its coverage on the surface of RM.This phenomenon facilitated further releasing Ca^(2+)from the internal RM,thereby enhancing CO_(2) mineralization efficiency.Meanwhile,the inclusion of RM significantly improved the alkalinity of the composite system,which not only promoted the dissolution of Ca^(2+)of the inert CaSO_(4)(H_(2)O)_(2) in CFA,but also accelerated CO_(2) mineralization rate.The investigation would be beneficial to CO_(2) mineralization using industrial solid wastes.

GC/MS Analysis of Fractional Extraction of Fusain from Tongting Bituminous Coal in CS_2

Fusain from Tongting (Huaibei, Anhui Province) bituminous (FTTB) coal was fractionally extracted using Soxhlet extractor with CS2. Then the extracts were analyzed with GC/MS. Comparison of experimental data between FTTB coal and clarain from Tongting bituminous (CTTB) coal was carried out. The results show that the kinds of small molecule components detected by GC/MS of FTTB are less than those of CTTB. Long-chain alkanes exist mostly in the extracts of fusain. Macromolecular networks are predominant in the FTTB coal mainly composed of inertinite in the coal petrography. The size of micropores in the FTTB coal is relatively small, and the development of micropores is relatively low. Thus the content of aromatic compounds with affinity for micropores is relative low in FTTB, while the content of long-chain alkanes with affinity for macromolecule networks is relatively high. Sub-components in exinite determine the distribution of long-chain alkanes extracted in the last stage. Odd-numbered carbon distribution appears when resin is most in exinite, while high carbon alkane distribution appears when exinite is dominant in cutinite. Small aromatic molecules are firstly packed in micropores, and exist in a free state after micropores are saturated.

Conversion of Fuel-N to N2O and NOx during Coal Combustion in Combustors of Different Scale

With focus on investigating the effect of combustor scale on the conversion of fuel-N to NOx and N20, experiments are carried out in three combustors, including single coal particle combustion test rig, laboratory scale circulating fluidized-bed boiler （CFB） and full scale CFB in this work. For single coal particle combustion, the majority of f-uel-N （65%-82%） is released as NOx, while only a little （less than 8%） fuel-N yields N20. But in labora- tory scale CFB, the conversion of fuel-N to N20 is increases, but the conversion of fuel-N to NOx is quite less than that of single coal particle combustion. This is because much char in CFB can promote the NOx reduction by in- creasing N20 formation. In full scale CFB, both of the conversion of fuel-N to NOx and the conversion of fuel-N to N20 are smaller than laboratory scale CFB.

Fire monitoring in coal mines using wireless underground sensor network and interval type-2 fuzzy logic controller

From the view of underground coal mining safety system, it is extremely important to continuous monitoring of coal mines for the prompt detection of fires or related problems inspite of its uncertainty and imprecise characteristics. Therefore, evaluation and inferring the data perfectly to prevent fire related accidental risk in underground coal mining (UMC) system are very necessary. In the present article, we have proposed a novel type-2 fuzzy logic system (T2FLS) for the prediction of fire intensity and its risk assessment for risk reduction in an underground coal mine. Recently, for the observation of underground coal mines, wireless underground sensor network (WUSN) are being concerned frequently. To implement this technique IT2FLS, main functional components are sensor nodes which are installed in coal mines to accumulate different imprecise environmental data like, temperature, relative humidity, different gas concentrations etc. and these are sent to a base station which is connected to the ground observation system through network. In the present context, a WUSN based fire monitoring system is developed using fuzzy logic approach to enhance the consistency in decision making system to improve the risk chances of fire during coal mining. We have taken Mamdani IT2FLS as fuzzy model on coal mine monitoring data to consider real-time decision making (DM). It is predicted from the simulated results that the recommended system is highly acceptable and amenable in the case of fire hazard safety with compared to the wired and off-line monitoring system for UMC. Legitimacy of the suggested model is prepared using statistical analysis and multiple linear regression analysis.

Tar formation characteristic of integrated process of coal pyrolysis with dry reforming of low carbon alkane over Ni/La_(2)O_(3)-ZrO_(2)

Coal pyrolysis integrated with dry reforming of low-carbon alkane(CP-DRA)is an effective way to improve tar yield.Ni/La_(2)O_(3)-ZrO_(2)with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition and obtain high tar yield in CP-DRA.In this study,the fraction distribution and component of tars from CP-DRA and coal pyrolysis in N_(2)atmosphere(CP-N_(2))were characterized by using several methods to understand the effect of DRA on coal pyrolysis.The isotope trace method was also used to discuss the role of low-carbon alkane in CP-DRA.The results showed that the tar from CP-N_(2)is mainly composed of aliphatic compounds with more C_(al),H_(al)and CH+CH_(2),and the tar from CP-DRA contains more Car,Har,and CH_(3),and has lower weight-average molecular weight and more light tar content than CP-N_(2).A small amount of C2H6 addition in CP-DRA will raise the ratio of H_(β)and CH+CH_(2).Electron paramagnetic resonance(EPR)analysis shows that the tar from CP-DRA has a higher radical concentration while the corresponding char has a lower radical concentration.The isotope trace experiment showed that alkanes provide·H,·CH_(3),etc.to stabilize the radicals from coal pyrolysis and result in more alkyl aromatic compounds during CP-DRA.

Fractionation of coal through organo-separative refining for enhancing its potential for the CO2-gasification

Coal gasification has already been extensively studied earlier under varying conditions of steam,CO2,O2,inert conditions.Belbaid coal and its e,N and NMP-DETA SCC products recovered through organo-refining under milder ambient pressure conditions were subjected to CO2-gasification in a fixed bed reactor under varying conditions.CO2 being an inert gas becomes the most challenging to be utilized during the gasification process.The SCCs showed better CO2-gasification reactivity than the raw Belbaid coal at 900°C.The use of the catalyst K2CO3 tremendously increased the gasification reactivity for both raw coal and the SCCs.The use of sugarcane bagasse for CO2-gasification along with raw coal as well as with residual coal was also studied.Gasification under CO2 atmosphere conditions was used to structurally understand the coals as the coal structure gets loosened after extraction.

Self-assembled Nanohybrid from Opposite Charged Sheets:Alternate Stacking of CoAl LDH and MoS2

Hybrid materials are attracting intensive attention for their applications in electronics, photoelectronics, LEDs, field-effect transistors, etc. Engineering new hybrid materials and further exploiting their new functions will be significant for future science and technique development. In this work, alternatively stacked self-assembled CoAl LDH/MoS2 nanohybrid has been successfully synthesized by an exfoliation-flocculation method from positively charged CoAl LDH nanosheets（CoAl-NS） with negatively charged MoS2 nanosheets（MoS2-NS）. The CoAl LDH/MoS2 hybrid material exhibits an enhanced catalytic performance for oxygen evolution reaction（OER） compared with original constituents of CoAl LDH nanosheets and MoS2 nanosheets. The enhanced OER catalytic performance of CoAl LDH/MoS2 is demonstrated to be due to the improved electron transfer, more exposed catalytic active sites, and accelerated oxygen evolution reaction kinetics.

Structural and microwave absorption properties of CoFe_(2)O_(4)/residual carbon composites

Electromagnetic interference,which necessitates the rapid advancement of substances with exceptional capabilities for bsorbing electromagnetic waves,is of urgent concern in contemporary society.In this work,CoFe_(2)O_(4)/residual carbon from coal gasification fine slag(CFO/RC)composites were created using a novel hydrothermal method.Various mechanisms for microwave absorption,including conductive loss,natural resonance,interfacial dipole polarization,and magnetic flux loss,are involved in these composites.Consequently,compared with pure residual carbon materials,this composite offers superior capabilities in microwave absorption.At 7.76GHz,the CFO/RC-2 composite achieves an impressive minimum reflection loss(RL_(min))of-43.99 dB with a thickness of 2.44 mm.Moreover,CFO/RC-3 demonstrates an effective absorption bandwidth(EAB)of up to 4.16 GHz,accompanied by a thickness of 1.18mm.This study revealed the remarkable capability of the composite to diminish electromagnetic waves,providing a new generation method for microwave absorbing materials of superior quality.

Conversions of fuel-N, volatile-N, and char-N to NO and N_2O during combustion of a single coal particle in O_2/N_2 and O_2/H_2O at low temperature

Oxy-steam combustion is a promising next-generation combustion technology.Conversions of fuel-N,volatile-N,and char-N to NO and N2O during combustion of a single coal particle in O2/N2and O2/H2O were studied in a tube reactor at low temperature.In O2/N2,NO reaches the maximum value in the devolatilization stage and N2O reaches the maximum value in the char combustion stage.In O2/H2O,both NO and N2O reach the maximum values in the char combustion stage.The total conversion ratios of fuel-N to NO and N2O in O2/N2are obviously higher than those in O2/H2O,due to the reduction of H2O on NO and N2O.Temperature changes the trade-off between NO and N2O.In O2/N2and O2/H2O,the conversion ratios of fuel-N,volatile-N,and char-N to NO increase with increasing temperature,and those to N2O show the opposite trends.The conversion ratios of fuel-N,volatile-N,and char-N to NO reach the maximum values at 〈O2〉=30 vol%in O2/N2.In O2/H2O,the conversion ratios of fuel-N and char-N to NO reach the maximum values at 〈O2〉=30 vol%,and the conversion ratio of volatile-N to NO shows a slightly increasing trend with increasing oxygen concentration.The conversion ratios of fuel-N,volatile-N,and char-N to N2O decrease with increasing oxygen concentration in both atmospheres.A higher coal rank has higher conversion ratios of fuel-N to NO and N2O.Anthracite coal exhibits the highest conversion ratios of fuel-N,volatile-N,and char-N to NO and N2O in both atmospheres.This work is to develop efficient ways to understand and control NO and N2O emissions for a clean and sustainable atmosphere.

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.

Influence of Recirculated Flue Gas Distribution on Combustion and NOx Formation Characteristics in S-CO_(2) Coal-fired Boiler

Supercritical carbon dioxide(S-CO_(2))Brayton power cycle power generation technology,has attracted more and more scholars'attention in recent years because of its advantages of high efficiency and flexibility.Compared with conventional steam boilers,S-CO_(2) has different heat transfer characteristics,it is easy to cause the temperature of the cooling wall of the boiler to rise,which leads to higher combustion gas temperature in the furnace,higher NOX generation concentration.The adoption of flue gas recirculation has a significance impact on the combustion process of pulverized coal in the boiler,and it is the most effective ways to reduce the emission of NOX and the combustion temperature in the boiler.This paper takes 1000MW S-CO_(2) T-type coal-fired boiler as the research target to investigate the combustion and NOX generation characteristics of S-CO_(2) coal-fired boilers under flue gas recirculation condition,the influence of recirculated flue gas distribution along the furnace height on the characteristics of NOX formation and the combustion of pulverized coal.The results show that the recirculated flue gas distribution has the great impact on the concentration of NOX at the boiler outlet.When the bottom recirculation flue gas rate is gradually increased,the average temperature of the lower boiler decreases and the average temperature of the upper boiler increases slightly;The concentration of NOx at the furnace outlet increases.

Reaction behaviour of Al_2O_3 and SiO_2 in high alumina coal fly ash during alkali hydrothermal process

The reaction behaviours of A1203 and SiO2 in high alumina coal fly ash under various alkali hydrothermal conditions were studied. The means of XRD, XRF, FTIR and SEM were used to measure the mineral phase and morphology of the solid samples obtained by different alkali hydrothermal treatments as well as the leaching ratio of SiO2 to A1203 in alkali solution. The results showed that with the increase of the hydrothermal treating temperature from 75 to 160 ~C, phillipsite-Na, zeolite A, zeolite P, and hydroxysodalite were produced sequentially while the mullite and corundum phase still remained. Zeolite P was massively formed at low-alkali concentration and the hydroxysodalite was predominantly obtained at high-alkali concentration. By the dissolution of aluminosilicate glass and the formation of zeolites together, the leaching efficiency of SiO2 can reach 42.13% with the mass ratio of A1203/SIO2 up to 2.19：1.

Zn^(2+)、Cr^(3+)掺杂对水热合成纳米CoAl_2O_4尖晶石色料的影响

以CoCl2·6H2O、ZnCl2、AlCl3和CrCl3·6H2O为原料,采用水热法合成了CoAl2O4(AB2O4)尖晶石型纳米钴蓝色料.采用色度分析、X射线衍射(XRD)、透射电镜(TEM)以及高分辨透射电镜(HRTEM)等研究了A位掺杂Zn2+和B位掺杂Cr3+时不同掺杂量以及不同水热合成温度对样品呈色、晶相组成及CoAl2O4尖晶石的晶粒大小、发育程度和晶面间距的影响.结果表明,掺杂Zn2+、Cr3+所得固溶体型钴蓝色料晶粒发育均不完整,颗粒较于相同水热条件下获得的未掺杂样品更细小.A位掺杂Zn2+可降低CoAl2O4色料的合成温度,在230℃便能制得呈色较佳的Co0.95Zn0.05Al2O4钴蓝色料.随着Zn2+掺杂量的增加,合成产物由蓝色转为绿色,且呈色逐渐变浅.B位Cr3+掺杂则随着掺杂量的增加,产物从蓝色逐步转为绿色,但呈色逐渐变深.就两者相比较,A位掺杂Zn2+更有利于色料明度值的提高而呈色鲜亮.

尖晶石型纳米CoAl_2O_4色料水热合成工艺研究

分别以钴、铝的氯化物、硝酸盐和硫酸盐为起始原料,NaOH为沉淀剂,用水热法合成了纳米尖晶石型钴蓝色料。分别研究了填充度、pH值、nCo/nAl、起始原料种类以及浓度等对合成色料物相组成、颗粒大小与形貌和呈色的影响。用XRD、TEM和色度分析对样品进行了表征。结果表明:以浓度分别为0.15 mol/L和0.3 mol/L的CoCl2.6H2O和AlCl3为起始原料,在填充度为70%、pH值为13、nCo/nAl为1/2的条件下,245℃水热培育20 h制得呈色良好的尖晶石型钴蓝色料,颗粒为八面体型,晶型完整,粒径多为100 nm以下。相同条件下,以钴、铝的硫酸盐为起始原料,产物中除CoAl2O4外,还有Co-Al LDHs、γ-AlO(OH)和β-Al(OH)3;以钴、铝的硝酸盐为起始原料,样品呈绿色,颗粒为八面体型CoAl2O4,粒径多为100 nm以上。

CoAl_2O_4/蜂窝陶瓷催化剂的制备及其催化臭氧化性能

采用涂覆法制备了CoAl_2O_4/蜂窝陶瓷催化剂。利用X射线衍射、N_2吸附-脱附和透射电镜等方法对所制备的催化剂进行了表征,并分析了其催化臭氧化降解对苯二酚的效能。结果表明,CoAl_2O_4/蜂窝陶瓷的晶相属于典型的尖晶石结构,具有较大的比表面积、孔容和孔径,分别达到77 m^2·g^(-1)、0.001 7 cm^3·g^(-1)和3.9 nm。CoAl_2O_4/蜂窝陶瓷催化臭氧化对苯二酚的去除率高达81.2%,COD去除率可达47.7%。在叔丁醇存在的条件下,对苯二酚的去除率显著下降,说明CoAl_2O_4/蜂窝陶瓷催化臭氧化遵循羟基自由基机理。

尖晶石型CoAl_2O_4纳米粉体的合成及表征

铝酸钴(CoAl2O4)是目前世界上最耐候、耐光、耐热、耐化学品的尖晶石型钴蓝颜料,为了解决传统钴蓝制备方法存 在的能耗高、产品粒径分布不均匀、易团聚等问题,尝试采用柠檬酸盐凝胶法合成了尖晶石型CoAl2O4纳米粉体,对样品进 行了TG-DSC、XRD、SEM等分析,考察了前驱体凝胶的热分解过程,以及煅烧温度对CoAl2O4晶化程度和粒度的影响. 确定了钴蓝最佳合成条件为:n(Co2+)/n(Al3+)=1∶3,柠檬酸与金属离子摩尔比为1∶1,pH值约为6.5,煅烧温度为 800℃.结果表明,采用柠檬酸盐凝胶法成功合成了平均粒径为60nm,粒度分布均匀的尖晶石型CoAl2O4纳米粉体,该法 具有合成成本低、制备工艺简单、易操作等优点.

燃煤在O_2/CO_2方式下NO_X生成特性的研究

O2 CO2 方式是一种能有效控制CO2 、SO2 与NOX 排放的新型高效清洁的煤燃烧技术 ,在自行设计的实验装置上研究了三种不同煤质特性的燃煤在这种方式下NOX 的生成与排放特征。主要研究结果表明当温度为 70 0℃及 90 0℃时 ,O2 CO2 方式下NOX 的排放量较空气气氛下大为降低。研究结果还表明O2 CO2 方式下温度、煤质特性、钙基吸收剂的加入对NOX

CoAl_2O_4蓝色的色料粒径对其色度的影响

目前,喷墨打印成为陶瓷装饰的主流技术。墨水的性能是影响喷墨打印效果的重要影响因素。为获得高稳定性的陶瓷墨水,需求粒径小、粒径分布窄的陶瓷色料。但是,超细的色料会改变其对光的吸收和反射,影响其在釉中的稳定性,进而影响其呈色。本论文采用燃烧法制备的超细CoAl_2O_4蓝色色料,通过粒度分布仪和CIE色度仪表征其粒径和色度。结果表明:砂磨机球磨10 h,可使粉体的平均粒径(d_(50))从6.40μm减小到0.33μm。相应地,CoAl_2O_4色料的色度值从L*=49.82,a*=0.05,b*=-50.90转变为L*=56.42,a*=-13.15,b*=-28.02。这说明随着粒径的减小,色料的明度增加,呈色鲜艳。但是b*值降低,色料的蓝色由深蓝转变为浅蓝。CoAl_2O_4色料在透明釉中也呈现相似的粒径-色度规律,但其影响较小。这规律有助于调控喷墨打印中蓝色的比例,以获得既定图案的颜色。

溶胶-凝胶水热合成法制备纳米CoAl_2O_4粉体

以仲丁醇铝和硝酸钴为原料,用溶胶-凝胶水热合成法制备了纳米CoAl2O4粉体,探讨了水热合成中前驱体的制备工艺条件,并用X射线衍射和扫描电镜等手段分析了水热系统中反应温度、反应时间对纳米CoAl2O4粉体的形成以及形貌的影响。结果表明:前驱体在250℃的水热系统中反应24h,能制备出较纯净、结晶完整、粒度均匀、粒径小、尖晶石结构的纳米CoAl2O4粉体,其平均粒度约为50～60nm。

柠檬酸螯合前驱体法制备CoAl_2O_4尖晶石型钴蓝色料

以Co(NO3).26H2O、Al(NO3).39H2O为前躯体,柠檬酸为螯合剂,乙二醇为溶剂,采用柠檬酸螯合前驱体法制备出CoAl2O4尖晶石型钴蓝色料。研究了不同热处理温度及钴铝比对色料呈色的影响,采用TG/DTA研究了螯合反应过程,采用色度仪、XRD、FT-IR等现代测试分析技术对样品进行了表征。结果表明,柠檬酸螯合前驱体法可在700℃制备出呈色良好的CoAl2O4尖晶石型钴蓝色料;前驱体经450℃热处理已经有尖晶石相生成,但其外观仍呈黑色;色料呈色随热处理温度的提高而随之加深;保温2h、钴铝比为1∶3制得的色料呈色效果最佳。