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2019年  第47卷  第1期

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论文
摘要:
以中国呼伦贝尔褐煤为原料,基于工业分析、元素分析、傅里叶变换红外光谱、气相色谱-质谱联用分析,考察140-230℃预热处理对褐煤650℃等温热解氧迁移的影响。结果表明,与未经预热处理的干煤热解相比,褐煤经200℃预热处理后热解,迁移至热解水和半焦中的氧分别下降7.55%和1.43%,迁移至焦油和气体中的氧分别增加6.66%和1.61%,焦油中酚类氧增加一倍。褐煤预热过程中氢键的减少与热解焦油中正己烷可溶物所含酚类化合物的增加,经原位红外漫反射光谱分析,发现源自OH…π、OH…N和羟基自缔合氢键在预热过程中断裂形成自由OH·,导致酚类化合物中苯酚和甲酚含量增加。
摘要:
研究水蒸气对不同赋存形态氮在热解过程中析出及转化规律有利于精细化调控氮氧化物的生成。利用X射线光电子能谱(XPS)仪分析了典型烟煤及其煤焦中氮的赋存形态,研究了温度、水蒸气浓度等因素对煤焦炭氮析出及转化特性的影响。结果表明,温度的升高以及一定范围内水蒸气浓度的增加有利于焦炭氮的析出,水蒸气浓度达到30%时,焦炭氮析出达到峰值;水蒸气的存在有利于煤焦中N-5和N-6等含氮结构物质从煤焦中析出,同时抑制N-Q和N-X等含氮结构物质的裂解。这是由于水蒸气的气化作用有利于芳香结构的分解,但同时高水蒸气浓度带来的H基团会与N-6结合从而形成N-Q,而由高水蒸气浓度带来的OH基团会促进N-6的氧化而生成N-X。
摘要:
A degradative solvent extraction at around 350℃ for low-rank coal or biomass wastes upgrading and fractionation was proposed in our previous work. The extraction yield of low-rank coal is relatively lower than that of biomass. In this work the blends of low-rank coal and biomass were treated by this method at 350℃ to investigate the interaction between them. The results showed that the yields and elemental compositions of the extracts obtained from the blends were slight different to the calculated results, which were calculated by assuming that there was no interaction between the coal and biomass. The slight promotion of yield was judged to be caused by the catalytic action of the minerals in the coal for thermal decomposition of biomass. It was worth to note that the elemental composition, molecular weight distribution, chemical structure, thermal decomposition behavior and thermoplastic behavior of the extracts obtained from low-rank coal, biomass and their blend, were rather similar to each other, independent of the properties of the raw feedstocks. Overall, the interaction between low-rank coal and biomass during the extraction was not significant. On the other hand, the proposed degradative solvent extraction method was fit not only by single low-rank coal and biomass but also by their blends to produce the product having similar physicochemical properties. This implied that an industrial system of degradative solvent extraction can use coal, biomass or their blends as feedstock at the same time without modification or adjustment.
摘要:
Four thermal dissolution soluble fractions (TDSFs) with different thermal dissolution soluble yields (TDSYs) obtained from thermal and co-thermal dissolutions (CTDs) of a Chinese sub-bituminous Shenfu (SF) coal and lignin were characterized by elemental analysis, FT-IR and synchronous fluorescence spectrum measurements. The hydro-liquefaction properties of the four TDSFs and SF raw coal with and without catalyst were compared and the recycled use property of the catalyst in hydro-liquefaction of the TDSF from CTD of SF coal and lignin was further probed. The results suggests that the TDSF from the thermal dissolution (TD) of SF coal contained much more amount of aromatic components and polyaromatic hydrocarbons (PAHs) with 4 and more rings than those from the CTD of SF coal and lignin at the same temperature. TDSFs gave much higher liquefaction conversions and oil yields than SF raw coal in hydro-liquefaction with or without catalyst. Almost all TDSF was converted with much high yield of oil and the TDSF from CTD of SF coal and lignin gave higher yield of oil than that from the TD of SF coal in hydro-liquefaction with Ni-Mo-S/Al2O3 catalyst which demonstrated a good reusability in the hydro-liquefaction of TDSF from the CTD of SF coal and lignin. Carbon deposition was hardly observed in the 4 times recycle used catalyst.
摘要:
采用纯矿物试剂模拟燃用高碱煤时炉内受热面典型的灰沉积层化学组成,利用热机械分析(TMA)、TG-DSC分析、高温煅烧实验结合XRD、SEM-EDS表征方法研究了不同Na2SO4含量灰沉积层的高温熔融过程及矿物间的多相反应机理。结果表明,掺混Na2SO4后沉积层熔化特征温度显著降低,Na2SO4的主要反应途径与掺混比例有关,当掺混比低于20%时,Na2SO4与SiO2、CaO、Al2O3反应主要转变为CaSO4和钠的硅铝酸盐;掺混比大于40%时则主要与CaSO4生成低熔点的钠钙复合硫酸盐。富Na2SO4沉积层颗粒在800℃时开始黏结;900-950℃时,霞石、钠长石等钠的硅铝酸盐发生低温共熔,同时Na2SO4和CaSO4生成的复合硫酸盐开始熔融,逐渐形成液相;1200-1250℃时,镁黄长石与含钙矿物发生强烈共熔,温度超过1300℃后矿物完全熔融成为自由液相。
摘要:
利用水热釜研究了低温水热预处理过程中高蛋白小球藻的水热降解特性,考察了125-200℃各相产物产率、元素组成、能量回收率和关键元素C、N的分布规律。结果表明,大量的C、N元素富集在水相中,且提高温度(>175℃)有利于脱氨反应进而提高水相中NH3的相对含量。随着预处理温度升高,N在油相产物中分布逐渐增加且在175℃后快速增加;固相产率及能量回收率逐渐降低,但同时其N/C和O/C也降低,表明水热预处理是一个提质过程。借助FT-IR、XPS、TG-FTIR-MS和Py-GC-MS对比分析了原料和藻渣的官能团结构和热降解特性。结果表明,水热预处理过程改变了C、N不同官能团的相对含量,与原料相比,藻渣中C-C相对含量增加,而C-N、C-O等相对含量降低;除了蛋白质-N和季胺类-N,预处理后藻渣中出现了少量吡啶-N。固体藻渣官能团组分含量和结构变化降低了热失重过程NH3和HCN的释放、及快速热解产物中含N杂环化合物的含量。
摘要:
从NaOH试剂浓度、反应温度与反应时间三个方面,对钡离子沉淀法提取不同温度段收集的生物油馏分中的酚类物质进行了实验研究,并利用气相色谱-质谱联用仪(GC-MS)对提取效果进行了分析。实验结果表明,钡离子沉淀法对愈创木酚类物质的提取效果较为突出,且NaOH浓度(1.0-6.0mol/L)、反应温度(30-50℃)与反应时间(10-40min)对愈创木酚的提取率影响较大。在NaOH浓度为5.5mol/L、反应温度为35℃、反应时间为20min时,提取率达到最大,其中,三个温度段收集的生物油即低温水相馏分、低温油相馏分与高温馏分中的愈创木酚提取率分别为34.1%、33.8%和33.5%。
摘要:
以羧甲基纤维素钠(CMC)与硫酸铁螯合反应生成的螯合物为碳前驱体,以浓硫酸为磺化试剂,制备新型碳基固体酸催化剂。采用红外(FT-IR)、X射线衍射(XRD)、吡啶红外、扫描电子显微镜(SEM)、热重分析仪(TGA)、能谱仪(EDS)对催化剂进行表征。结果表明,该催化剂同时具有Brønsted和Lewis酸位点,是具有双酸位的碳基固体酸催化剂。将其应用到油酸与甲醇的酯化反应制备生物柴油体系中,考察了不同反应条件对油酸转化率的影响。在反应温度为70℃,反应时间为6h,油酸与甲醇物质的量比为1:10,催化剂用量为油酸质量7.5%条件下,油酸的转化率可达到96.8%。此外,对该催化剂的稳定性进行研究发现该催化剂有着良好的重复使用性和疏水性。
摘要:
设计合成了两种阴离子功能化离子液体抗氧化剂([MI][C6H5COO]、[Ch][C6H5COO]),采用核磁共振氢谱、傅里叶红外光谱对其结构进行了表征,并研究了两种离子液体抗氧化剂对小桐子生物柴油抗氧化性、铜片腐蚀性和油溶性能的影响。结果表明,离子液体抗氧化剂可有效提高生物柴油氧化稳定性,在添加量为0.3‰时,[MI][C6H5COO]的小桐子生物柴油诱导期提高了238%,超过了中国国家标准(6 h),[Ch][C6H5COO]的小桐子生物柴油诱导期提高了141%,未达到中国国家标准。进一步研究了两种离子液体抗氧化剂的油溶性,油溶性能从大到小的顺序为[MI][C6H5COO] > [Ch][C6H5COO] > GA(合成离子液体抗氧化剂的原料)。实验表明,合成的两种离子液体抗氧化剂中含有亲油阳离子的[MI][C6H5COO]综合性能明显优于含有亲水阳离子的[Ch][C6H5COO]。
摘要:
A series of H-ZSM-5 zeolites with a silicon to aluminum ratio of 50-4000 but similar crystal size were synthesized and characterized by XRD, N2 sorption, NH3-TPD and Py-FTIR; the intrinsic effect of silicon to aluminum ratio on the selectivity to propene in the conversion of methanol to propene (MTP) was investigated. The results show that a complete conversion of methanol can be initially achieved over H-ZSM-5 with a silicon to aluminum ratio from 50 to 1600 and then the initial conversion of methanol decreases progressively with further increasing the silicon to aluminum ratio. Meanwhile, the selectivity to propene increases monotonically with an increase in the silicon to aluminum ratio of H-ZSM-5 for MTP with a complete methanol conversion, suggesting that a high Si/Al ratio for H-ZSM-5 may enhance the propagation of the alkene-based methylation/cracking cycle relative to the arene-based methylation/dealkylation cycle in MTP. A critical value of acid density, viz., [AS]S, is required to achieve the maximum propene selectivity for MTP with a complete methanol conversion; this critical[AS]S value is 0.175 μmol/m2 for the H-ZSM-5 zeolite under current reaction conditions.
摘要:
采用定向同晶取代法制备了一系列镍孔雀石前驱体的Cu-Ni双金属催化剂。考察了前驱体结构以及催化剂表面组成对催化剂催化性能的影响,并采用浆态床反应器对催化剂的CO加氢制乙醇性能进行评价。实验结果表明,采用定向同晶取代法可以制备出(Cu,Ni)2CO3(OH)2纯物相,取代后的Ni2+主要富集在前驱体(Cu,Ni)2CO3(OH)2表面。焙烧后形成的(Cux,Ni1-x)O固溶体均匀地分散在CuO晶体结构中。还原后的催化剂中Cu、Ni相互均匀分散形成活性界面,促进了低碳醇的合成。其中,不连续分布的Ni活性位点阻止了碳链的进一步增长,从而提高了乙醇选择性。当Ni/Cu原料比为45:100时,(Cux,Ni1-x)O固溶体与CuO之间有较强的相互作用,表现出最好的反应活性和乙醇选择性。
摘要:
采用固相反应法制备了钙钛矿结构的BaZr0.9Y0.1O3,并用BaZr0.9Y0.1O3作为载体负载Fe2O3,通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)观察负载型催化剂的晶相结构和微观形貌,同时考察了制备的催化剂的逆水煤气反应催化活性。结果表明,BaZr0.9Y0.1O3粉体1200℃煅烧5h时,负载型催化剂具有较好的催化活性;BaZr0.9Y0.1O3对逆水煤气反应有一定的催化作用,负载少量的Fe2O3催化剂可以明显促进CO2还原,在空速为1.13h-1,温度为650℃时,CO收率可以达到31%;催化剂经过长时间运行催化效果良好,制备的催化剂活性较稳定。
摘要:
采用第一性原理计算的方法,研究了不同浓度及不同位置Cr掺杂Cu2O体系的缺陷形成能、电子结构和可见光区域的光催化性质及产生机理。结果表明,本征Cu2O显示半导体特性,在可见光区域吸收很弱;不同浓度、不同位置的Cr掺杂体系均是稳定的,显示金属特性。与本征Cu2O相比,随着Cr掺杂浓度的增大,体系在可见光范围内的吸收峰均有不同程度的增强,并且两个Cr原子近邻掺杂时可见光区域的吸收系数最大,光催化效率最强。态密度分析发现,Cr掺杂体系在可见光范围的吸收主要由Cr 3d态电子的带内跃迁产生;不同掺杂浓度和结构构型主要影响材料在长波长段的物理性质,而对短波长段的性质影响很小。因此,通过增大Cr掺杂浓度及调控掺杂位置可以提高Cu2O在可见光区域的光催化效率,推动Cu2O在光催化方面的发展。
摘要:
通过1-乙基-3-甲基咪唑硫酸乙酯离子液体(EMIES)和对甲苯磺酸(p-TsOH)的混合物制备EMIES/p-TsOH型低共熔溶剂。其结构特征通过红外光谱、氢谱和热重技术进行了分析。并以EMIES/p-TsOH作为催化剂与萃取剂,H2O2作为氧化剂研究了其对模拟油中的硫化物的脱除性能。考察了反应温度、n(H2O2)/n(S)比、低共熔溶剂加入量及硫化物类型对脱硫效果的影响。在最佳的条件下,模拟油中二苯并噻吩(DBT)、4,6-二甲基二苯并噻吩(4,6-DMDBT)和苯并噻吩(BT)的脱除率分别为96.2%、92.2%和88.8%。经过五次循环使用后,DBT的脱除率仍达到93.6%。对该脱硫体系进行了动力学分析,其表观活化能为66.4kJ/mol。
摘要:
基于Fe基金属有机骨架(MOFS)作为载体,采用浸渍法制备了负载6% Mn的Mn/MIL-100(Fe)脱汞剂。在模拟烟气中,搭建固定床研究了Mn/MIF-100(Fe)脱除单质汞(Hg0)性能。采用X射线衍射分析(XRD)、X射线电子能谱(XPS)、N2吸附-脱附(BET)和热重分析(TGA)对材料进行表征。研究表明,Mn/MIF-100(Fe)脱除单质汞(Hg0)效率较高,在250℃,空速(GHSV)为180000h-1时,脱汞(Hg0)效率达82%以上。Mn/MIF-100(Fe)主要的脱汞机理是催化氧化,Mn的负载促进了汞的吸附,并随着烟气温度的提高,单质汞的氧化效率逐渐提高。O2和NO促进汞的脱除,SO2和NH3抑制汞的脱除。Mn/MIL-100(Fe)整体上对复杂烟气的适应能力强。
摘要:
通过水平管式气化炉和化学吸收法,对比研究了矿化垃圾热解半焦(ARC)和常规垃圾热解半焦(NRC)在水蒸气和CO2气化过程中腐蚀性气体(HCl和H2S)的析出特性,考察了气化温度、气化介质类型和流量对腐蚀性气体析出特性的影响。当气化温度升至950℃,ARC在水蒸气气化过程中的碳气化率、HCl和H2S产率分别为66.1%、100%和74.9%,而其在CO2气化过程中的碳气化率、HCl和H2S产率分别为77.8%、100%和2.9%;NRC在水蒸气气化过程中的碳气化率、HCl和H2S产率分别为98.8%、100%和53.7%,而其在CO2气化过程中的碳气化率、HCl和H2S产率分别为100%、96.2%和10.3%。以NRC为原料,考察了水蒸气和CO2流量对其HCl和CO2析出特性的影响。NRC的HCl和H2S产率均随水蒸气流量增加而增加,但当水碳比大于等于3.3时,其促进作用不再明显。NRC的HCl产率随CO2流量的增加而增加,而H2S产率随CO2流量的增加而减小。