Gasification of Green River oil shale kerogen

Green River oil shale kerogen when reacted with a sodium tetra-chloroaluminate melt, gasifies efficently under a low pressure of hydrogen. The function of the tetrachloroaluminate melt is to promote radical formation and rearrangement of aliphatic units through chemical effects in addition to the role the solvent plays as a thermal transfer agent. The mechanism of gasification appears to involve the generation of electron deficient sites, which either undergo bond breakage or rearrange resulting in the formation of low-molecular-weight hydrocarbons, normally gases or near gases at ambient temperatures. The product gases are sufficiently clean that conventional scrubbing techniques may be used and that the process may be operated on a semi-continuous basis.     

油页岩干酪根化学结构特性分析

利用先进的测试技术对5种不同地区的油页岩干酪根分别进行XRD、¹³C NMR与FT-IR分析,获得重要结构信息。通过XRD检测分析,确定5种干酪根以长程无序的聚合状态存在。采用¹³C NMR技术表征出干酪根的碳原子化学结构,并获得碳骨架结构的18个重要参数。最后利用FT-IR技术对干酪根官能团进行定性分析,与 ¹³C NMR实验结果互相验证,得到干酪根化学结构的详细信息。结果表明:油页岩干酪根脂碳结构最多,高达60%～90%。其中又以亚甲基碳为主,有77%～90%,且多数为直链结构,脂环或支链结构较少。芳碳结构除桦甸以单环为主外,其余均为单环和多环结构并存,其中多环结构以迫位缩合为主。氧结构总体以碳氧单键(醇、酚或醚基)和C=O两种形式存在,其中羧基类C=O多于羰基类C=O。变质程度低的干酪根中存在较多C=O,而高变质程度的干酪根则以碳氧单键C-O为主。     

Separation of kerogen from green river oil shale

The complex analysis of the chemical composition and technological properties of oil shale from the Green River formation was carried out. The technical characteristics and granulometric composition of test samples and the element compositions of the mineral and organic matters of shale rocks were determined. The structure of organomineral aggregates formed upon the crushing of shale rocks was studied by electron microscopy. Based on the experimental data, a procedure was developed for the separation of kerogen from the oil shale by physicochemical processing.     

A comparison of the dissolution of model compounds and the kerogen of Green River oil shale by oxidation with perchloric acid — A model for the kerogen of Green River oil shale

A stepwise degradation of a kerogen concentrate of Green River oil shale was effected by oxidation with perchloric acid of varying boiling point and concentration. Dissolution of the kerogen concentrate occurred between 160 and 170°C. Several model compounds were also oxidized with perchloric acid. The model compounds were polyethylene, graphite, nylon, and polyethylene oxide. The results indicated that the kerogen was similar to polyethylene oxide. The results of this study and previous work were used to present a model for the structure of the kerogen of Green River oil shale.     

稠油低温氧化动力学实验与模型研究

注空气辅助蒸汽吞吐/蒸汽驱是稠油开发的一新工艺。针对典型稠油油样,进行了稠油-空气的低温氧化(LTO)动力学实验,研究了温度(100～150℃)和压力(8～17 MPa)对稠油-空气氧化特性的影响。基于Arrhenius方程,确定了反应的活化能、频率因子,并给出了反应焓,建立了稠油-空气低温氧化的动力学模型,为稠油油藏注空气数值模拟提供了理论基础。低温氧化实验结果表明,稠油具有很好的低温氧化活性,氧化反应速率与温度、氧气分压、原油的性质有关。在实验的温度范围内,氧化反应能有效消耗氧气,产生大量CO2。     

蒙脱石对油页岩干酪根热解特性的影响

选取中国桦甸、抚顺、窑街3个地区油页岩,酸洗得到各干酪根样品。应用TG-FTIR技术对不同升温速率下各干酪根与蒙脱石共热解行为进行了研究,并利用Coats-Redfem积分法对升温速率为10℃/min下的干酪根掺混样品进行热解反应动力学分析,获得了蒙脱石对干酪根热解产物析出规律的影响及热解过程的活化能(E)和指前因子(A).结果表明,随着蒙脱石掺混比例增大,桦甸和抚顺干酪根热解失重率先升高后降低;在热解过程中,440℃前干酪根与蒙脱石掺混样品的热解失重率较干酪根单独热解低,而440℃后其热解失重率较干酪根热解有所提高;蒙脱石掺混比例增大使得各干酪根热解产物中CH₃/CH₂值有所增加;有蒙脱石掺混的干酪根热解活化能相比干酪根热解活化能有所降低。表明蒙脱石对油页岩干酪根热解具有物理吸附和裂解催化两种作用,且随着热解过程的加深和蒙脱石配比的改变而不同。最后,对升温速率为10℃/min的样品进行了热解反应动力学分析,进一步探讨了蒙脱石对干酪根的热解影响机理。     

Study of pyrolysis kinetics of oil shale

The pyrolysis experiments on oil shale samples from Fushun, Maoming, Huangxian, China, and Colorado, USA, were carried out with the aid of thermogravimetric analyzer (TGA) at a constant heating rate of 5 °C/min. A kinetic model was developed which assumes several parallel first-order reactions with changed activation energies and frequency factors to describe the oil shale pyrolysis. The kinetic parameters of oil shale pyrolysis were determined on the basis of TGA data. The relationship between the kinetic parameters was further investigated and the correlation equations of x_∞-E and ln A-E were obtained. These equations show that the final fractional conversion of each parallel reaction, x_∞(j), can be expressed as an exponential function of the corresponding activation energy. The plot of ln A-E for different reactions becomes a straight line. These relationship equations can provide important information to understand the pyrolysis mechanism and to investigate the chemical structure of oil shale kerogen.     

油页岩半焦燃烧动力学研究

燃烧动力学是研究油页岩半焦颗粒燃烧特性的基础。利用热重分析仪对油页岩半焦进行了恒温燃烧实验研究,在排除外扩散影响的基础上,分析了燃烧温度、氧气浓度对油页岩半焦燃烧过程的影响。在实验范围内,氧气浓度和燃烧温度均能对油页岩半焦燃烧速率产生重要影响,更高的氧气浓度和燃烧温度可以加快油页岩半焦燃烧速率。结合实验结果,建立了考虑氧气浓度影响的油页岩半焦燃烧动力学模型,发现油页岩半焦燃烧速率与氧气浓度的0.97次方呈线性关系。模型计算结果与实验结果符合较好,为进一步研究油页岩半焦大颗粒燃烧特性提供了燃烧动力学基础。     

DTA derived kinetics of Jordan oil shale

The thermal behaviour of Jordan oil shale has been studied in a DTA apparatus in an He atmosphere. The thermal curves for both untreated and decarbonated shale exhibited two distinct endothermic peaks related to the softening and evolution of organic matter. The first peak relates to molecular rearrangement of the kerogen where nonisothermal kinetics found that the activation energy (E_a) in the range 13.4–25.1 kJ mol^?1 for both untreated and decarbonated samples. For the second peak, E_a was obtained from first order kinetics and varied from 54.9 kJ mol^?1 for decarbonated shale to 79.6 kJ mol^?1 for untreated samples. The effect of particle size on the DT curves was studied and showed a drift from zero base line. Spent shale for reference material improved the profile of DTA curves and minimized drift as compared to use of α-alumina.     

油页岩过热蒸汽的干燥动力学

以油页岩颗粒作为干燥物料,以过热蒸汽和热空气分别作为干燥介质,进行了油页岩干燥实验的研究。当颗粒粒径减小时,油页岩干燥速率越大;过热蒸汽和热空气温度增大时,干燥速率也越大。对比相同条件下过热蒸汽和热空气干燥油页岩的平均干燥速率,发现当干燥介质温度超过逆转点温度时,过热蒸汽条件下的平均干燥速率大于热空气下的数值。实验得出粒径分别为9,7,5 mm的油页岩颗粒逆转点温度值分别是154,179,177℃;逆转点温度值是个变量,随颗粒粒径大小变化而变化。颗粒粒径越大时逆转点温度值越小,粒径较小时逆转点变化不大。采用薄层干燥模型对油页岩的干燥数据进行动力学模拟,可得修正Page模型(Ⅱ)干基水分比w模拟值与实验值的最大绝对偏差是12%,综合比较发现修正Page模型(Ⅱ)能较好地描述油页岩在过热蒸汽条件下的干燥过程。     

窑街油页岩热解动力学研究

利用差热分析仪对窑街油页岩进行不同恒速升温速率的热解实验,考察升温速率对热解的影响,随着升温速率加快,失重曲线和最大热解速率向高温区。建立Friedman动力学模型对热解数据进行了数学处理,得到了活化能的变化范围为120～190kJ·mol^-1,而且活化能E与频率因子A的对数呈良好的线性关系,对认识油页岩干酪根的热解机理和化学结构提供重要信息。     

Composition and kinetics of oil generation from non-isothermal oil shale retorting

Oil shale retorting has been carried out under non-isothermal conditions between 623 and 773 K and at different pressures(78 and 765 kPa). The shale oil is separated into five individual components: polar, weak polar, saturates, aromatics and olefin, using a comprehensive analytical procedure. The effects of retorting pressure and heating rate have been studied. The oil yield under high pressure (765 kPa) is ≈10% less than the oil yield under ambient pressure (78 kPa). Much of this reduced yield can be accounted for by the reduced amount of polar component formed at high pressure. Heating rates of 1.67 × 10^?2, 6.67 × 10^?2and 8.33 × 10^?2Ks^?1 have been used; a higher heating rate causes a delay in the appearance of the oil. A simplified kinetic scheme is proposed which includes the distribution of liquid products and pressure effects. The activation energies and frequency factors of generation reactions for total oil and individual components have been obtained.     

Mathematical models for kinetics of batchwise hydrogenation of shale oil

Hydrogenation of shale oil in a batch autoclave is described by a second order kinetic equation depending on the hydrogen current concentration (H) and on the current value of a total characteristic of the oil (x_i), both approaching to their equilibrium levels (H_∞, x_i∞). Algorithms are proposed to estimate the values of hydrogenation rate coefficient (k) and H_∞ from the plot of decrease in hydrogen concentration in time versus H at isothermal conditions. A new concept “specific change of the characteristic” (β_i = dx_i / dH) is introduced to handle various x_i (oil yield, viscosity, density, iodine number, and yield of the fraction 200–275 °C).The equilibrium constants (K_i) and β_i for the characteristics are estimated on the basis of experimental results. The temperature-dependencies for k, K_i and β_i are determined. A scheme is proposed to predict current values of H and x_i for different H₀, T_max and oil mass under isothermal and non-isothermal conditions.The model deduced and the coefficients and constants found can be applied for quantitative evaluation of catalysts and initial oils for hydrogenation.     

Thermogravimetry and decomposition kinetics of British Kimmeridge Clay oil shale

The characteristics of volatile matter evolution and the kinetics of thermal decomposition of British Kimmeridge Clay oil shale have been examined by thermogravimetry. TG has provided an alternative to the Fischer assay for shale grade estimation. The following relation has been derived relating TG % volatiles yield to the shale gravimetric oil yield: oil yield (g kg^?1) = (TG volatiles, % × 5.82) ? 28.1 ± 14.5 g kg^?1. A relationship has also been established for volumetric oil yield estimation: oil yield (cm³ kg^?1) = (TG volatiles, % × 4.97) – 5.43. TG is considered to give a satisfactory estimation of shale oil yield except in certain circumstances. It is found to be less reliable for low yield shales producing <≈40 cm³ kg^?1 of oil (≈10 gal ton^?1) where oil content of the TG volatiles is low: volumetric yield estimation accuracy is affected by variations in shale oil specific gravity. First order rate constants, k = 4.82 × 10^?5s^?1 (346.3 cm³ kg^?1shale) and k = 6.78 × 10^?5s^?1 (44.6cm³ kg^?1shale) have been obtained for the devolatilization of two Kimmeridge oil shales at 280 °C using isothermal TG. Using published pre-exponential frequency factors, an activation energy of ≈57.9 kJ mol^?1 is calculated for the decomposition. Preliminary kinetic studies using temperature programmed TG suggest at least a two stage process in the thermal decomposition, with two maxima in the volatiles evolution rate at ≈450 and 325 °C being obtained for some samples. Use of published pre-exponential frequency factors gives activation energies of ≈212 and 43 kJ mol^?1 for these two stages in the decomposition.     

基于气固流态化原理的油页岩干燥动力学

为了考察气固流化床干燥器能否使油页岩含水质量分数达到要求,以柳树河油页岩颗粒为原料,研究进口气体温度和颗粒直径对油页岩干燥性能的影响,采用薄层干燥模型,对油页岩干燥实验数据进行模拟,确定油页岩干燥方程和干燥速率方程,建立油页岩干燥速率特征常数和有效扩散系数之间的关联式。研究结果表明:薄层干燥模型中修正Page模型Ⅰ适合描述油页岩的干燥过程;油页岩在流化床内干燥过程主要发生在降速干燥阶段,进口气体温度越高,油页岩颗粒直径越小,所需干燥时间越短,进口气体温度为350℃时,使2.4 mm油页岩含水质量分数低于5%,所需干燥时间为2.5 min。     

SO2 emissions from the oxidation of retorted oil shale

Sulphur dioxide emissions from the oxidation of retorted Colorado oil shale at temperatures > 530 °C are <0.2% of the sulphur present. Sulphur is retained in the oxidized shale by displacement reactions with carbonates to form sulphates. Thermal decomposition of carbonates is not necessary.     

多因素影响下的煤低温氧化特性试验研究

为研究氧浓度、粒度和挥发分对采空区遗煤低温氧化过程的影响,利用油浴式程序升温试验装置设计了煤低温氧化试验,研究了不同影响因素条件下煤的耗氧速率和放热强度,验证了氧浓度、粒度和挥发分等对煤低温氧化特性的影响,通过对试验数据分析,得到了煤低温氧化特性受各因素影响的变化规律。试验结果表明:在一定范围内,氧浓度的增加会加快煤的耗氧速率,提高反应的放热强度,促进煤的氧化,但不会改变氧化反应的趋势;粒度较大的煤耗氧速率低,反应释放的热量小,氧化过程缓慢且强度较低;煤的挥发分降低后,耗氧速率和反应的放热强度也随之减小,其自燃临界温度将显著提高。     

Reaction kinetics of the gasification of Michigan Antrim oil shale char

Both CO₂ and steam gasification kinetics were determined for Michigan Antrim shale char using TGA techniques in combination with on-line gas chromatography. While the reaction kinetic expressions were similar to those previously derived for Green River Formation (western USA) and Swedish Ranstad shale chars, the gasification rates were found to be on the same order as those of Ranstad char but significantly lower than those of western shale char. In addition, the gas produced from steam gasification was found to be significantly higher in CO than the corresponding gas from western shale char. This and the presence of significant quantities of CO₂ lower the attractiveness of Antrim char as a source of synthesis gas or hydrogen.     

Thermogravimetrically and differential scanning calorimetrically derived kinetics of oil shale pyrolysis

Thermogravimetry (TG) and differential scanning calorimetry (d.s.c.) were used to investigate the kinetics of non-isothermal pyrolysis of Aleksinac oil shale from Yugoslavia. The samples used included oil shale, demineralized oil shale and bitumen extracted from the original, as well as from the thermally treated oil shale.Kinetic parameters were determined by assuming a single first-order kinetic model, using the integral method for TG analysis, and ASTM procedure E-698 for d.s.c. analysis. The influence of cracking catalyst addition was examined with respect to the overall kinetics and to conversion in particular temperature regions.Higher values of kinetic parameters were obtained by d.s.c. analysis, and the reasons for the differences between those and the TG results are discussed.     

美国绿河油页岩中沥青热解特征及动力学

沥青是油页岩中的重要有机质,也是油页岩中油母质热解产油和气过程的重要中间产物,对其热解研究有利于加深油页岩/油母质热解理解。通过索氏萃取提取出了绿河油页岩中的沥青,并对其进行了不同升温速率下热解实验。基于热重（TGA）数据,使用Friedman法计算了沥青热解的活化能,并通过活化能分布特征,推测沥青热解可能包含三个过程。接着,使用双高斯函数对含有交叠峰的DTG曲线进行反褶积处理,分解成三个峰,依次对应每一个过程。使用最小二乘法获得了这三个过程的活化能、指前因子和反应模型通式,并将获得的通式与四类固态物质热解模型中的11种理想模型进行对比,辨识出上述三个过程均遵循n级反应模型。