Steam reforming of gaseous by-products from bitumen oil using various supported Ni-based catalysts

The steam reforming process is an efficient route for producing hydrogen gas which, along with lower costs compared to other methods, has an acceptable efficiency rate. In this study, by using an experimental setup we tried to investigate the effect of various catalysts on the amount of tar and produced hydrogen from steam reforming of gas by products from bitumen oil and to introduce effective parameters in the process of hydrogen production. As temperature increased, the amount of tar conversion to gas increases and the amount of hydrogen surged accordingly. With increase in temperatures from 400 to 900°C, tar elimination also improved from 39% to 99% for Ni/Al₂O₃, from 30.5 to 93.1 for Ni/olivine and from 25.7 to 83.6 for Ni/Fe₂O₃. As a result, it was concluded that the Ni/Al₂O₃ catalyst has been more successful in eliminating the tar, although there is not much difference between the activities of the three catalysts.     

Thermal cracking of tar generated from steam gasification of petroleum residue using dolomite particles

Gasification is a thermochemical process that converts carbon-based fuels into a clean synthesis gas (so-called syngas). The produced syngas can be used directly as a fuel to produce electricity in gas engines or an intermediate chemical for production of Dimethyl ether (DME), methanol (MeOH), and/or ethanol. In this work, an unsteady-state, kinetic model that is used to predict the gas composition and performance indicators in presence of dolomite was developed. Results showed a good performance for biomass gasification in presence of dolomite as a catalyst. It is also concluded that the tar destruction ratio (TDR) exhibits an increasing trend with increasing [CaMg (CO₃)₂]/[C] from 0.1 to 0.9 (mg/mg), while after that, the increase levels off.     

A kinetic model for gasification of heavy oil with in situ CO2 capture

Gasification process is being developed to obtain environmentally clean and efficient syngas from solid (coal, biomass, and municipal solid waste) or liquid (heavy oil and waste lubricant oil) fuels for power generation. A gasification kinetic model of heavy oil in the presence of CaO that can predict syngas yield, tar concentration, and performance parameters has been developed. Results showed that the CaO plays a major role for a significant reduction in carbon dioxide during the process. Based on the operating conditions, it was also found that there is an optimum condition for tar yield. Modeling results were validated against experimental data and found to be in good agreement.     

Hydrogen production by catalytic gasification of petroleum residue

The liquid fuel gasification to obtain a clean flue gas for power generation and produce chemicals such as methanol is a most promising attempt to reduce the greenhouse gas emissions and air pollutants. In this paper, an equilibrium model of liquid fuel gasification was developed by the method of Gibbs free energy minimization. Two kinds of catalysts: Ni/CeO₂/Al₂O₃ and Ni/Al₂O₃ were used to explore the influence of catalysts and operating conditions on hydrogen yield and char conversion. Over the ranges of operating conditions studied, the maximum hydrogen yield reached 52.47 vol%, whereas the char conversion varied between 45.2% and 98.5%. The results indicated that an appropriate reaction temperature is favorable for higher hydrogen production and char conversion. The model was validated with experimental data obtained from a fluidized bed gasifier.     

Sulfuration Pretreatment of Ni/Al2O3 Catalyst to Remove Butadiene in FCC C4 Fraction

Abstract

The Ni-based catalysts have more advantages than the most widely used Pd-based catalysts in selective hydrogenating of the butadiene in fluid catalytic cracking (FCC) C₄ fraction. But the selectivity and stability of the Ni-based catalysts aren't good. The sulfuration pretreatment is an effective process to improve the performance of the Ni/Al₂O₃ catalysts. The sulfuration conditions of the Ni/Al₂O₃ catalyst have been studied in this article. The results showed the fittest conditions are that the catalyst was in-situ presulfurized for 60 min by the solution of S concentration 0.07 mol/L. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis indicated that the presulfurization declined the Ni crystal dimension.     

Gasification of n-C7 asphaltenes using Ni-based catalysts

Catalytic performance of two Ni-based catalysts (Ni-Pt and Ni-Pt-Al) in steam gasification of n-C7 asphaltenes (C7A) was examined. The influence of the catalysts composition and operating parameters (residence time and temperature) on hydrogen yield and char conversion was studied showing a high hydrogen production and a low char formation compared to Ni-Pt alone. From the result of the gasification of rice C7A over Ni-Pt/Ni-Pt-Al catalysts, it is found that the raising the Pt/Ni ratio increases the quantity of generated hydrogen, but this increase is greater in the presence of the Ni-Pt-Al catalyst because the tar cracking process improves with increased collisions and also with improved activation energies of the reactions in the presence of Al.     

Ni/P-HY催化剂上正构烷烃的加氢转化

研究了磷改性对Ni/HY催化剂表面性质和催化反应性能的影响。NH3-TPD和Py-dFTIR的结果表明，磷改性导致了催化剂表面上的B酸酸量减少，酸强度提高，CO-DRIFTS结果表明，磷与镍相互作用，提高了金属的分散度，并有效地提高了催化剂的金属中心与酸中心的比例，因此，在正辛烷临氢转化反应中，少量磷改性的Ni/HY催化剂可以显著地提高加氢异构化的选择性，减少裂解反应。     

Ce-Ni/Al_2O_3催化剂的制备及其结构性能的研究

采用热分析和X 射线衍射实验技术,研究了两种制备方法对Ce Ni/Al2O3体系热分解行为和结构性能的影响;以Ni/Al2O3、Ce/Al2O3为参照研究了Ce、Ni的相互作用及其对催化剂结构性能的影响。实验发现,同时负载Ce、Ni两组分的Ce Ni/Al2O3样品,由于Ce、Ni的相互作用,使前体样品中负载的Ce、Ni物种分解温度不同程度地降低,催化剂样品中的Ce、Ni物种得到不同程度的分散;Ce、Ni的相互作用因制备方法不同而异,Ce、Ni依次分步浸渍并一起热分解的Ce Ni/Al2O3样品中,Ce、Ni的相互作用较强,其前体样品中Ce、Ni物种的分解温度明显降低,催化剂样品中Ce、Ni的分散较好,而当先浸Ce,热分解后再浸Ni时,这种作用就要弱得多。     

氧化镍改性的ZSM-5催化剂对甲苯和甲醇择形甲基化反应稳定性的影响

在常压下,以N₂为载气,采用固定床反应器考察了NiO改性的ZSM-5催化剂催化甲苯和甲醇择形烷基化反应的性能。采用Ar物理吸附、XRD、XRF、TEM、XPS、H₂-TPR、NH₃-TPD、Py-IR、UV-Vis、UV-Raman、TG、GC-MS等手段表征所制备的催化剂。结果表明,在ZSM-5催化剂上负载质量分数为3%或5%的Ni,催化剂的稳定性明显得到提高。在催化甲苯甲基化反应后,NiO改性ZSM-5催化剂上出现了金属Ni,这可能是由于在积炭过程中,伴随着氢转移过程或者是水消炭反应过程而产生的H2将NiO还原为金属Ni;而且,催化剂的积炭量明显降低,同时作为积炭前驱体的稠环芳烃的生成量也明显减少,推测可能是由于金属Ni的存在,抑制了烷基苯脱氢生成稠环芳烃积炭前驱体的反应,因而提高了催化剂的稳定性。     

Aspen Plus simulation of steam-gasification of different crude oils: A detailed comparison

The gasification process is being developed to obtain environmentally clean and efficient syngas from solid (coal, biomass, and municipal solid waste) or liquid (heavy oil and waste lubricant oil) fuels for power generation. An Aspen Plus model of crude oil gasification in presence of steam as a gasifying agent that can predict syngas yield, tar concentration, and performance parameters was developed. Effects of some critical parameters such as gasification temperature, steam-fuel-ratio on hydrogen yield, tar content, and char conversion of three different crude oils were explored. Results showed that the hydrogen yield increases by increasing steam/fuel ratio from 0.5 to 0.7 (wt/wt), and then reduces smoothly due to the endothermic behavior of methane reforming reaction, which releases three hydrogen moles. It also found that as the temperature increases within the range, hydrogen yield increases dramatically, which can be explained according to the Le Chatelier's principle on the endothermic reforming reactions of methane and tar cracking. Modeling results validated against the experimental measurements and found to be in a good agreement.     

覆炭载体镍催化剂脱氢活性和表面酸性研究

以制备的覆炭γAl2O3(CCA)为载体,制备了Ni/CCA系列催化剂,并对其环己烷脱氢活性进行了考察;以吡啶为探针分子,用热重分析(TG)和差示热分析(DTA)技术测定了Ni/CCA催化剂的表面酸性,并计算了Ni/γ-Al2O3和Ni/CCAⅡ两种催化剂的脱吡啶活化能。结果表明,Ni/CCA催化剂的脱氢活性优于Ni/γ-Al2O3催化剂;CCA载体的覆炭量对Ni/CCA催化剂的脱氢活性有一定的影响,当覆炭的质量分数在7.92％时出现脱氢活性峰,并且Ni/CCA催化剂具有较好的低温脱氢活性;CCA载体和Ni/CCA催化剂表面的吡啶物理吸附量和化学吸附量均低于γ-Al2O3载体和Ni/γ-Al2O3催化剂,CCA载体和Ni/CCA催化剂的脱附化学吸附毗啶的DTA曲线上有两个吸热峰,说明在CCA载体和Ni/CCA催化剂上有两个表面酸性中心;求得吡啶在Ni/γ-Al2O3和Ni/CCAⅡ催化剂的强酸中心的脱吡啶活化能分别为188 kJ/mol和225 kJ/mol,在弱酸中心的脱吡啶活化能分别为30 kJ/mol和31 kJ/mol。     

METALLOPETROPORPHYRINS AS PROCESS INDICATORS: SEPARATION OF PETROPORPHYRINS IN GREEN RIVER OIL SHALE PYROLYSIS PRODUCTS

Product oils from the LLNL Hot-Recycled-Solids (HRS) retorting process were separated to isolate and concentrate the metallopetropor-phyrins. A modified column chromatography procedure developed previously for heavy crude oils and tar sand bitumens was used. The fractions were then examined by UV-vis spectroscopy to determine categories of porphyrins and other related metal-containing species.

No porphyrins were found in the hexane fraction (least polar fraction); Ni porphyrins were found in the methylene chloride fraction (moderate polar fraction); and a free-base porphyrin-like species was found in the methanol fraction (the most polar fraction) of some of the oils. The CH₂Cl₂ fractions were further examined to quantify the amount of porphyrins detected. In the whole oil samples examined, ∼ 40 wt % of the Ni was found as Ni petroporphyrins. The vacuum residua of two product oils had ∼ 20 wt % of the Ni bound as Ni por-phyrins indicating that the vacuum distillation process destroys porphyrins.     

苯酚羟基化合成苯二酚反应产物分离过程酚焦油的形成原因

对苯酚羟基化合成苯二酚产物分离过程酚焦油的形成原因进行了研究。模拟研究表明,在含有邻苯二酚和对苯二酚的混合溶液中,邻苯二酚比对苯二酚更易氧化缩合生成酚焦油。苯酚羟基化反应液中催化剂残留和催化剂被溶解形成的金属离子对酚焦油的形成具有促进作用;对苯醌的存在对酚焦油的生成具有促进作用;泄漏进入的氧或空气可加速苯二酚的氧化缩合反应;酚焦油生成量随常压脱水和减压精馏过程操作温度的升高、操作时间的延长而增加。醋酸能溶解催化剂活性组分,存在醋酸和金属离子残留问题,从而增加了羟基化反应产物分离过程酚焦油的生成量。在羟基化反应产物中加入Na2HSO3,使羟基化反应产物中的对苯醌还原,同时减少羟基化反应产物中的溶解氧含量,从而起到了抑制脱水和精馏过程中酚焦油生成的作用。     

Sn修饰的Ni/γ-Al_2O_3催化乙二醇液相重整制氢

通过湿浸渍法制备了一系列Ni与Sn摩尔比不同的NiSn/γ-Al2O3催化剂,将该催化剂用于乙二醇液相重整制氢反应。实验结果表明,Ni与Sn摩尔比为42的NiSn-42/γ-Al2O3催化剂表现出最佳的活性和H2选择性,乙二醇转变为气体产物的转化率和H2选择性分别为65.4%和88.4%;Sn的加入使H2选择性大幅提高;随Sn修饰量的增大,催化剂的活性先增加后降低。表征结果显示,适量Sn修饰到Ni/γ-Al2O3催化剂上能促进Ni的分散;NiSn-42/γ-Al2O3催化剂比其他催化剂具有更大的活性比表面积,因此显示出较佳的活性。同时考察了NiSn-42/γ-Al2O3催化剂的稳定性,实验结果表明,NiSn-42/γ-Al2O3催化剂达到稳态时能保持初活性的34%,重整过程中Ni晶粒的长大和团聚是该催化剂失活的主要原因。     

煤焦油加氢生产清洁燃料油技术的开发

在中型试验装置上,以煤焦油全馏分为原料,采用加氢精制-加氢裂化两段法工艺技术路线,对煤焦油原料进行加氢提质,以生产清洁燃料油。考察了反应温度、压力、空速和氢油比对加氢精制生成油性质的影响规律;并对加氢精制尾油开展了加氢裂化试验,确定了适宜的加氢裂化工艺条件。结果表明：在适宜的工艺条件下,石脑油和柴油馏分收率超过95%,其中柴油馏分硫质量分数低于10 ?g/g、十六烷值接近45。催化剂2 600 h运转稳定性考察期间,产品性质保持稳定。本技术实现了煤焦油轻质化、清洁化利用的目的,具备工业长周期运转的条件。     

煅烧还原一步制备Ni基催化剂及在CH4-CO2重整反应中的应用

采用大豆油研磨法制备了Ni/C-SiO_2系列催化剂,并用于CH_4-CO_2重整反应。通过XRD、TG-DTG、BET、H_2-TPR、CO_2-TPD等对催化剂进行了物理性能表征,利用固定床连续反应对催化剂进行了催化性能测试。结果表明,研磨法制得的催化剂前驱体在惰性气氛N2中煅烧后,催化剂上的镍元素全部转变成了Ni~0,实现了煅烧还原一步制备中孔Ni基催化剂。CH_4-CO_2重整反应后的催化剂上存在两种炭,一种是催化剂制备时残留的碳源炭,另一种是重整反应过程中产生的可致催化剂失活的积炭。考察了助剂CeO_2、ZrO_2、La_2O_3对催化剂性能的影响,结果表明,与Ni/C-SiO_2催化剂相比,Ni-CeO_2/C-SiO_2、Ni-ZrO_2/C-SiO_2、Ni-La_2O_3/C-SiO_2催化剂中Ni~0的粒径降低了,Ni-CeO_2/C-SiO_2、Ni-La_2O_3/C-SiO_2催化剂的反应活性提高了,反应后Ni-ZrO_2/C-SiO_2、Ni-La_2O_3/C-SiO_2催化剂上的积炭减少了。助剂La_2O_3不仅提高了催化剂活性,而且降低了催化剂上的积炭量,使用Ni-La_2O_3/C-SiO_2催化剂进行CH_4-CO_2重整反应,总碳转化率达到了52%。     

镍盐前驱体对Ni改性HZSM-5择形催化甲苯与甲醇合成对二甲苯反应性能的影响

分别以硝酸镍、氯化镍、硫酸镍和乙酸镍为前驱体,采用浸渍法制备了Ni改性HZSM-5催化剂,并考察了其对甲苯甲醇烷基化反应合成对二甲苯的催化性能。采用XRD、TG-DTG、N₂吸附-脱附、H₂-TPR和NH₃-TPD手段对催化剂进行了表征。结果表明,由于镍盐前驱体中阴离子种类的不同,活性Ni物种在催化剂中的分散状态和存在形式不同,导致Ni改性催化剂具有不同的烷基化催化活性和加氢活性;与母体催化剂相比,催化甲苯甲醇烷基化反应的甲苯转化率降低,对二甲苯选择性呈现不同变化,并且Ni的加氢作用延缓了催化剂的积炭过程。以硝酸镍为前驱体制备的Ni改性催化剂中活性Ni物种晶粒尺寸较小,分散度较高,具有较高的烷基化催化活性和加氢活性,并且稳定性也比母体催化剂有所提高。     

Characterization of trace metals in source identification of tar balls deposited along the southern coast of the Caspian Sea

The southern coast of the Caspian Sea, Iran, is frequently affected by tar balls deposition. Tar balls on the shores, as oil pollution warnings, attract a huge public concern and will have long-term impacts to the marine environment. The concentrations of seven metals (Ni, V, Co, Mn, Fe, Cr, and Cu) were studied in tar ball samples collected from five different locations and analyzed using ICP-OES. Co/Ni and V/Ni markers are fairly uniform in the tar balls, and it indicates that the tar balls are from an identical source. V/(V + Ni) ratios of the tar balls were compared with those of Kazakhstan and Azerbaijan crude oils. The results showed that the ratio measured in tar balls remained quite stable, at a value of approximately 0.57, which is comparable to the value of Kazakhstan crude oil, which was approximately 0.44. The data show that a remarkable difference exists in Azerbaijan crude oils, which varies between 0.03 and 0.18, and that of tar balls. It may be concluded that, based on the V/(V + Ni) ratios, the majority of the tar balls were probably formed from the Kazakhstan crude oil.     

水热处理对Mo-Ni/Al2O3催化剂活性结构和催化硫醚化反应性能的影响

采用水热处理的方法对Mo Ni/Al2O3催化剂的微观孔结构性质和负载金属的结构性质进行调变,并考察调变后催化剂在硫醚化反应中的催化性能。结果表明,水热处理可增加催化剂的平均孔径,有利于产物中形成的大分子异构硫醚的扩散,维持催化剂的稳定性;还可以降低负载金属与载体间的作用,提高负载金属的硫化度,增加Ni Mo S活性中心数目。然而,这些对催化剂结构性质的促进作用,不仅提高了硫醚化反应过程的硫醚化反应和二烯烃选择加氢反应性能,还大大促进了烯烃的加氢饱和反应,造成反应产物辛烷值的损失。     

负载型Ni/Y催化剂性能与结构研究

采用饱和浸渍法制备了Ni/Y双功能催化剂,考察了Ni负载量对催化剂性能的影响。通过N2物理吸附（BET）、X射线衍射（XRD）、核磁共振（NMR）、透射电镜（TEM）等技术对催化剂结构进行了表征。结果表明：随着Ni负载量的增加,催化剂结晶度、比表面积、孔体积和B酸量均减小,而催化剂临氢再生性能则随着Ni负载量的增大先增大后减小,Ni负载量为2.0%的2Ni/Y催化剂临氢再生性能最好,可使催化剂寿命恢复到初始寿命的92.8%;随着负载量的增加,Ni活性中心数增加,进而再生性能增加;但金属负载量过大,Ni分散性变差,造成Ni颗粒团聚长大,催化剂再生性能变差。