The influence of catalyst regeneration on the composition of zeolite-upgraded biomass pyrolysis oils

The composition of oils derived from the on-line, low pressure zeolite upgrading of biomass pyrolysis oils from a fluidized bed pyrolysis unit have been investigated in relation to the regeneration of the zeolite catalyst. The catalyst used was H-ZSM-5 zeolite. The gases were analysed by packed column gas chromatography. The composition of the oils before catalysis and after catalyst upgrading were analysed by liquid chromatography fractionation, followed by coupled gas chromatography—mass spectrometry of each fraction. In particular, the aromatic and oxygenated aromatic species were identified and quantified. In addition, the oils were analysed for their elemental composition and molecular weight range using size exclusion chromatography. Before catalysis the biomass pyrolysis oil was highly oxygenated but after catalysis a highly aromatic oil was formed with high concentrations of monocyclic aromatic hydrocarbons. In addition, significant concentrations of polycyclic aromatic hydrocarbons (PAH) were formed. Regeneration of the zeolite catalyst showed that continued regeneration reduced the effectiveness of the catalyst in converting biomass pyrolysis oils to an aromatic product. Elemental analysis of the upgraded oils showed an increase in the oxygen content of the oil with increasing regeneration of the catalyst. The molecular weight range of the oils was found to decrease markedly after catalysis, but continued regeneration of the catalyst increased the molecular weight range of the upgraded oils. Detailed analysis of the uncatalysed oils showed they contained low concentrations of aromatic and PAH species which markedly increased in concentration after catalysis. The overall effect of increasing catalyst regeneration was a decrease in the concentration of aromatic hydrocarbons and PAH. Also as the catalyst was regenerated, the number of methyl groups on the parent single ring aromatic compound or PAH increased. The oxygenated aromatic species in the oil before catalysis were mainly, phenols and benzenediols and their alkylated homologues. After catalysis some of the oxygenated species were reduced and some increased in concentration. A dual mechanistic route is suggested for the formation of aromatics and PAH during the catalytic upgrading of biomass pyrolysis oils: (1) the formation of low-molecular-weight hydrocarbons on the catalyst which then undergo aromatization reactions to produce aromatic hydrocarbons and PAH; (2) deoxygenation of oxygenated compounds found in the non-phenolic fraction of the pyrolysis oils which directly form aromatic compounds.     

Determination and mutagenic activity of nitrogen-containing thiophenic compounds in coal-derived products

Polycyclic aromatic compounds containing both nitrogen and sulphur heteroatoms in aromatic rings were determined in a coal-derived liquid and a coal tar by capillary column gas chromatography and gas chromatography-mass spectrometry. G.c. with a flame photometric detector was used to analyse the nitrogen-containing polycyclic aromatic compound fraction obtained by adsorption chromatography on neutral alumina. The four possible isomers of the azadibenzothiophenes, and various other azathiophenic compounds, were positively identified by comparison with retention data of newly synthesized standard compounds. The aminodibenzothiophenes were the major nitrogen/sulphur-containing heterocycles in the coal liquid, while the azathiophenic compounds were the major ones in the coal tar. The differences between the two coal-derived products were related to the reaction conditions during their production. The four isomers of the azadibenzothiophenes were assayed for mutagenicity using the Ames test and compared with the mutagenicities previously reported for the aminodibenzothiophenes. It was found that the azadibenzothiophenes were not mutagenic, as opposed to the aminodibenzothiophenes.     

Comparative chemical composition and biological activity of single- and two-stage coal liquefaction process streams

Samples from several integrated two-stage coal liquefaction (ITSL) process streams were collected under both normal and off-normal operating conditions. Selected crude materials were tested for their ability to initiate tumorigenicity in the initiation/promotion assay in mouse skin. Crude materials and their chemical class fractions were assayed for microbial mutagenic activity in the standard Ames test with S. typhimurium TA98, and selected samples were also subjected to the Chinese hamster ovary mammalian cell assay for mutagenicity. Mass spectral and gas chromatographic—mass spectral (g.c.—m.s.) analyses were carried out on these materials. Results were compared with those for analogous materials from solvent refined coal (SRC) single stage liquefaction processes. In general, the ITSL distillates were of higher molecular weight, higher hydroaromatic content, lower nitrogen content and were somewhat less alkylated than the analogous SRC materials. Compared to the SRC coal liquefaction materials, the ITSL distillates and bottoms materials collected under normal run conditions were substantially less active in both the microbial and mammalian cell mutagenicity assays. These same materials were also less active than ITSL samples collected under off-normal conditions. G.c.—m.s. analyses showed that ITSL materials collected under normal operating conditions were substantially reduced in amino polycyclic aromatic hydrocarbon content when compared to both the off-normal ITSL, and SRC materials. Activity of the ITSL materials as initiators of tumorigenesis was greater than expected, based on results from the in vitro assays and not significantly different than that of the SRC materials. The higher initial boiling point of the ITSL distillates probably accounts for much of their greater than expected initiating activity compared to the SRC materials.     

Chemical composition and toxicological activity of liquefaction materials derived from different feed coal ranks

Samples of recycle solvent from the bottoms recycle mode of the EDS direct coal liquefaction process using bituminous, sub-bituminous, and lignite coal feeds were chemically characterized and tested for toxicological response. The H-Coal heavy fuel oils derived from bituminous and sub-bituminous coals were also analyzed. Chemical methods of analysis included adsorption column chromatography, high-resolution gas chromatography, gas chromatography/mass spectrometry, and low-voltage probe-inlet mass spectrometry. The toxicological activity of selected samples was evaluated using the standard histidine reversion microbial mutagenicity assay, an initiation/promotion assay for mouse-skin tumorigenicity, and a static bioassay with Daphnia magna for aquatic toxicity of the water-soluble fractions. Both materials derived from the bituminous coals had the following chemical characteristics as compared to their sub-bituminous coal and/or lignite-derived counterparts: higher concentrations of polycyclic aromatic hydrocarbons (PAH), nitrogen-containing polycyclic aromatic compounds, and hydroxy-substituted PAH; lower concentrations of aliphatic hydrocarbons; and a generally increased molecular weight distribution of approximately ten atomic mass units. Toxicological testing indicated a general trend of increased biological activity of the coal liquefaction products with increasing feed coal rank.     

兰炭废水深度处理效果及污染物去除特性研究

采用混凝沉淀-活性炭吸附的方法对兰炭废水的生化处理出水进行深度处理,利用气相色谱分析了处理前后废水中有机物的组成变化。试验结果表明,经过混凝处理,兰炭废水CODCr和色度的去除率分别达到61.8%和84.7%,甲苯去除率达到93.83%,多环芳烃、酚类物质和杂环化合物的去除率分别达到94.76%、86.93%和93.65%,苯酚、邻甲酚和邻苯二甲酸二丁酯被完全去除。沉淀出水采用颗粒活性炭吸附,最终出水色度为16倍,CODCr的质量浓度为76 mg/L,酚类、多环芳烃去除率分别达到99.4%和97%,苯类和杂环化合物被全部去除。     

NiO含量对加氢裂化催化剂反应性能的影响

采用浸渍法制备WO<,3>含量相同和NiO含量不同的系列加氢裂化催化剂.利用XPS和TEM等对催化剂进行表征,结果表明,引入适量Ni,有利于提高W的硫化度,WS<,2>片晶长度随NiO含量增加而增长,而片晶堆垛层数随Ni含量增加呈现出先增大后减小的趋势.以十二烷为模型化合物评价催化剂加氢裂化性能,结果表明,随着NiO含...     

Oxidation of methane over Pt and Pd supported on alumina in lean-burn natural-gas engine exhaust

Catalytic oxidation of hydrocarbons in lean-burn natural-gas engine exhaust has been studied for Pt and Pd supported on alumina. A Pt–Pd/alumina catalyst exhibited higher and longer-lasting hydrocarbon oxidation activity than Pt–Rh/alumina, Pt/alumina, and Pd/alumina catalysts. Increasing the palladium content in Pt–Pd/alumina catalyst increased the oxidation activity and had more durability. While increasing the platinum content a little bit also improved the activity, adding much more did not. Supporting the platinum on alumina retarded the sintering of Pd and PdO, thus lengthening the oxidation activity of the Pt–Pd/alumina catalyst.     

Liquid products of the hydropyrolysis of brown coal form the Lena basin

Liquid hydrocarbon products were obtained by the hydropyrolysis of brown coal from a deposit in the northern Lena basin on an iron-containing catalyst. The individual and group compositions of gasoline and diesel fractions were determined with the use of capillary chromatography and chromatography-mass spectrometry. The gasoline fraction with a boiling point to 180°C was characterized by a high octane number; it mainly contained monocyclic aromatic hydrocarbons and normal alkanes. The diesel fraction mainly consisted of bi- and tricyclic aromatic hydrocarbons and C₁₃–C₁₉ n-alkanes.     

Hydrodesulfurization and hydroconversion of heavy FCC gasoline on PtPd/H-USY zeolite

In the search for catalysts suitable for upgrading fractions of FCC gasoline, PtPd/USY zeolite was investigated. The objectives of the work were to reduce simultaneously the sulfur, nitrogen and aromatic contents of heavy FCC gasoline having various sulfur (30–203 ppmw) and 28 ppmw nitrogen contents. The process conditions were the following: temperature: 200–300 °C; pressure: 30 bar; liquid hourly space velocity: 1.0–3.0 h⁻¹; H₂/hydrocarbon ratio: 500 m³/m³. The results indicated that PtPd/H-USY zeolite catalyst can be applied for the desulfurization of heavy FCC gasoline up to 203 ppm sulfur content. When a base heavy FCC gasoline fraction of 30 ppmw sulfur content was used the catalyst was able to reduce the aromatic content by 14 abs.% as well as sulfur and nitrogen contents to <1 ppmw in one step. Blending calculations were made to evaluate the quality of a full range FCC gasoline obtained by mixing the desulfurized heavy FCC gasoline and the untreated light cut.     

Separation and characterization of large-ring number polycyclic aromatic hydrocarbons in non-distillable, pyridine soluble coal-liquids

Low-pressure liquid chromatography, high-performance liquid chromatography, and field ionization mass spectrometry (f.i.m.s.) were used to obtain compositional information on large-ring number polycyclic aromatic hydrocarbon (PAH) present in a non-distillable coal liquid sample. A highly selective h.p.l.c. method for the separation of (PAH) from polar compounds was applied to nitrogen-compound fractions derived from a Wyodak non-distillable ( > 427 °C) coal-liquid sample. F.i.m.s. analyses revealed that the PAH subfractions isolated by the h.p.l.c. procedure contained large-ring number PAH and relatively few nitrogen compounds. The methods developed can generally be applied to the analyses of complex organic mixtures, and in conjunction with other methods, can yield detailed polycyclic aromatic hydrocarbon compositional information.     

The Influence of Platinum Addition on Nano-Crystalline Ceria Catalysts for the Total Oxidation of Naphthalene a Model Polycyclic Aromatic Hydrocarbon

Abstract  

The effect of adding Pt to a highly active ceria polycyclic aromatic hydrocarbon total oxidation catalyst has been investigated for the oxidation of naphthalene. The addition of Pt to ceria suppressed the performance of the catalyst for total oxidation. The addition of Pt reduced catalyst surface area, decreased the ceria crystallite size, decreased the concentration of ceria defects and increased the reducibility of the catalyst. The suppression of activity has been attributed to strong metal-support interaction between Pt and ceria, which limits the availability of lattice oxygen for the oxidation process, which follows the Mars-Van Krevelen redox mechanism in the absence of Pt. It is postulated that the presence of dispersed Pt, alters the mechanism of naphthalene oxidation over the ceria catalyst.     

注蒸汽条件下供氢催化改质稠油及其沥青质热分解性质

利用CWYF-Ⅰ型高压反应釜模拟热采条件下,以甲酸作为供氢体.以自制的油溶性有机镍盐为催化剂进行的稠油水热裂解反应.考察了供氢体的加入对催化水热裂解反应前后稠油黏度、族组成及硫含量的影响,并采用TG-DTA分析法对供氢催化改质反应前后稠油中沥青质的热转化行为进行了分析.结果表明,随着加入供氢体质量分数增加,供氢催化水热裂解后稠油降黏率增大,饱和烃、芳香烃含量增加,胶质,沥青质含量降低,同时硫含量下降.供氢催化水热裂解反应后的稠油中沥青质TG-DTA曲线分析表明,供氢催化水热裂解反应后稠油中沥青质失重量高于催化水热裂解反应前稠油中含有的沥青质的失重量.经过供氢催化水热裂解反应,稠油中沥青质的稳定性下降.     

加氢裂化变压器油提质探索及工业应用

中国石油化工股份有限公司金陵分公司加氢裂化装置运行至末期,产品变压器油中多环芳烃含量增加且颜色较深,造成销售困难;本文介绍了利用NJBMZDA-II催化剂针对加氢裂化变压器油开展的产品提质试验情况,结果表明在反应温度150℃、空速为3.0 h~(-1)、压力为3.0 MPa、氢油体积比500∶1的条件下,原料中总芳烃含量降低了13%,其中稠环芳烃含量降低为0.6%,产品赛氏比色提高了7个单位;利用公司尾油异构化装置工业应用情况表明,在空速2.68 h~(-1)、反应温度178℃、反应压力2.95 MPa、氢油体积比305∶1工况下,变压器油稠环芳烃含量、油品色泽等指标都能达到产品指标。     

重质芳烃油选择性加氢工艺研究

以油浆抽提得到的重质芳烃油为原料,通过选择性加氢工艺降低其中有害的稠环芳烃(PAHs)化合物,得到的精制油为橡胶用环保芳烃油。实验分别对反应温度、压力、时间以及一段、二段加氢工艺对PAHs转化率的影响进行了考察,同时运用BET及EDS对2种硫化态催化剂进行了表征,以考察催化剂的活性及选择性。结果表明,Ni-W/γ-Al2O3催化剂活性及选择性较Ni-Mo/γ-Al2O3高。实验证明:通过选择性加氢可大幅度降低重质芳烃油中PAHs质量分数,一段加氢采用Ni-W/γ-Al2O3催化剂,在反应温度280℃、压力8 MPa、时间6 h的条件下,原料PAHs转化率达到46.24%;二段加氢采用Ni-Mo/γ-Al2O3催化剂,在与一段相同的反应条件下,PAHs转化率达到32.94%。经2段加氢后,产物中PAHs质量分数由起始的58.13%降到21.05%,总转化率达到63.79%,液体总收率91.72%。     

不同条件下重油催化裂化产物的烃组成变化

利用气相色谱和质谱对重油在提升管催化裂化中试装置上反应前后烃组成进行了考察,探讨了在相近转化率时物料反应前后的烃组成变化特点.结果表明,在优化条件下,重油中大分子多环芳烃组分和胶质中的链烷基和环烷基有效裂化生成烯烃和环烷烃.并使双环和三环芳烃分子落人到柴油馏分;烯烃和环烷烃进一步发生芳构化和脱氢反应生成烷基苯.优化条件下热裂化的产物C1和C2的产率明显降低,催化反应产物C3和C4的产率基本不变;重油馏分中大分子多环芳烃组分和胶质中芳环之间的桥链或环烷基链的断裂导致汽油馏分中C5～C7小分子产物明显增加,烯烃的芳构化反应使C7和C8短支链的芳烃产率增加;柴油馏分中烷基苯和多环环芳烃增加,而环烷烃和环烷基苯含量减少.     

HZSM-5催化剂在MTG反应中的积炭失活

在固定床不锈钢反应器中进行了HZSM-5分子筛催化甲醇制汽油(MTG)反应的催化性能和失活实验。采用热重、X射线衍射、FT-IR、低温氮吸附-脱附、色谱-质谱联用仪等方法对催化剂进行了表征。结果表明,在反应进行到336 h时,甲醇转化率为40%,汽油收率低至12.6%,催化剂严重失活,但在700℃有氧再生后活性恢复,且保持了完整的MFI结构。积炭是催化剂失活的主要原因,大部分积炭沉积在分子筛微孔中,积炭物种主要是带有双键的聚合态化合物和稠环芳烃。     

改善炭黑分散性的研究

炭黑在生产过程中,由于烃类物质不完全裂解,特别是多环芳烃包裹在炭黑颗粒表面,导致炭黑的分散性比较差。采用硝酸对炭黑进行处理,氧化除去炭黑表面的多环芳烃,可提高炭黑的着色强度和分散性。     

Effects of oxygenate concentration on species mole fractions in premixed n-heptane flames

Atmospheric pressure, laminar, premixed, fuel-rich flames of n-heptane/oxygen/argon and n-heptane/oxygenate/oxygen/argon were studied at an equivalence ratio of 1.97 to determine the effects of oxygenate concentration on species mole fractions. The oxygen weight percents in n-heptane/oxygenate mixtures were 2.7 and 3.4. Three different fuel oxygenates (i.e. MTBE, methanol, and ethanol) were tested. A heated quartz micro-probe coupled to an on-line gas chromatography/mass spectrometry has been used to establish the identities and absolute concentrations of stable major, minor, and trace species by the direct analysis of samples, withdrawn from the flames. The oxygenate addition has increased the maximum flame temperatures and reduced the mole fractions of CO, low-molecular-weight hydrocarbons, aromatics, and polycyclic aromatic hydrocarbons. The reduction in mole fractions of aromatic and polycyclic aromatic hydrocarbon species by an increase in oxygenate concentration was more significant.     

Fe/CaO催化剂对脱灰徐州烟煤热解特性的影响

煤热解是一种重要的煤炭分质利用技术，但热解过程中产生的副产物焦油危害极大，催化改质是高效清洁利用煤焦油的方法之一。本文采用溶胶凝胶法制备Fe/CaO催化剂，在管式炉反应器上对脱灰徐州烟煤进行了催化热解实验，对研究催化裂解煤焦油具有重要的意义。结果表明：Fe/CaO催化剂可以明显促进热解气的产生，热解气中CO₂、CO和CH₄的产量均不断增加。Fe/CaO催化剂促进了液体产物的催化裂解，导致液体产率明显下降。Fe/CaO催化剂促进焦油中的稠环芳烃向脂肪烃和轻质芳烃转化，此外，Fe/CaO催化剂还对萘类化合物的产生有促进作用。Fe/CaO催化剂催化后焦油中两环化合物的含量增多，三环及以上的化合物含量减少，焦油分子量呈减少的趋势。     

Effect of process distillation on mutagenicity and cell-transformation activity of solvent-refined,coal-derived liquids

Blended SRC-II process streams, representing a full boiling range distillate material, were fractionally distilled into non-overlapping 50 °F cuts with boiling points between 300 and 850 °F. Another set of 18 distillate cuts were obtained with boiling points ranging between 138 and 1055 °F. Distillate cuts were assayed for mutagenic activity using the histidine reversion assay with Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, as well as for mammalian-cell transformation activity in the Syrian hamster embryo test, and DNA damage in the prophage induction assay. Samples were also separated into chemical class fractions by alumina column chromatography and analysed by high resolution gas chromatography so that the chemical composition of the cuts could be related to their relative activity in the different assays. In the mammalian cell transformation and microbial mutagenicity assays, significant activity was found almost exclusively in distillate cuts with components boiling > 700 °F, with the highest activity in the transformation assay observed for cuts > 800 °F. All of the distillate cuts showed increased levels of DNA damage as expressed by lambda prophage induction in Escherichia coli 8177. However, the greatest activity was associated with distillate cuts with boiling points in the 800 °F + range. Chemical analysis of the 50 °F distillate cuts showed a variety of polycyclic aromatic hydrocarbons (PAH) and amino-PAH compounds to be present in the distillate cuts boiling > 700 °F and essentially absent from cuts boiling < 700 °F. The sample set of non-overlapping (50 °F) cuts were reblended according to the proportions of each cut found in the original blend material. These reblended composites were then assayed to compare their activity with that predicted from the activities of the component distillate cuts. The reblending experiments indicated the microbial mutagenicity response was essentially additive. Mammalian cell transformation activities were non-additive, indicating a compositional effect on the expression of transforming agents in the complex mixture.