EMPIRICAL APPROACH FOR THE DIAGNOSTIC ANALYSIS OF CHEMICALLY RELATED OIL YIELD LOSSES DURING THE RETORTING OF OIL SHALE

The analysis of chemically related oil yield losses during the retorting of oil shale is important for understanding the chemistry of a process, supplying data for modeling efforts and process control of a production facility. Previously developed gas chromatographic correlations for evaluating oil yield losses were duplicated using combined gas chromatograph/mass spectrometric data. Evaluation of these results through calculation of local oil yields indicated that they were higher than expected when compared to material balance oil yields.

A new correlation was developed to estimate the fraction of oil lost by cracking plus combustion. The approach to the new correlation was based on selection of steranes and pentacyclic triterpanes as the species in shale oil which would undergo cracking and combustion to yield selected aromatic compounds. Evaluation of the results from this correlation for determination of local oil yields was found to produce acceptable results.

The two approaches for estimating the fraction of oil lost by cracking plus combustion are compared. The differences appear to be that the earlier approach is dependent upon severe cracking and combustion conditions. The new approach for determining the fraction of oil lost by cracking plus combustion appears to be applicable to a wider range of process conditions and therefore is more useful in research.     

EVALUATION OF OIL YIELD LOSSES DURING THE RETORTING OF OIL SHALE AT LOW VOID FRACTIONS. PART 1. THE EFFECTS OF PARTICLE SIZE AND RESOURCE GRADE

ABSTRACT

The economics of vertical modified in situ (VMIS) retorting of oil shale can be improved by decreasing the quantity of oil shale which is mined and transported to the surface. However, decreasing the quantity of oil shale removed from the retort also decreases the void fraction in the shale bed and this can affect the retorting process. The Western Research Institute has completed a series of experiments designed to investigate the effects of different experimental parameters on retorting oil shale at low void fractions. The effects of changes in the experimental parameters, oil shale particle size and resource grade, on oil yield losses have been evaluated using previously described oil yield loss diagnostic methods. These methods show that cracking–plus–combustion losses are the major and more variable source of chemically related oil yield losses. In experiments investigating changes in oil shale particle size, these losses correlate with the temperature differential between thermocouples in the rubble and in the interior of the oil shale particles. The data from the experiments investigating the effects of changes in resource grade on oil yield losses do not follow this correlation because of additional combustion of the produced oil during the lean resource grade experiment. Coking losses from experiments investigating both parameters were found to decrease with increased heating rate of the oil shale when significant differences in the heating rate were observed.     

AIR OXIDATION OF EASTERN OIL SHALES OF KENTUCKY. II. THE EFFECTS OF AMBIENT AUTOXIDATION

ABSTRACT

Ambient air oxidation leads to lower Fischer assay oil yields and often lower process yields from retorting of eastern oil shales. Slight changes in the kerogen and mineral matter of the oil shale and in its pyrolysis products, both liquid and gaseous, were evident following autoxidation. Experimental observations suggest that the hydrogen deficiency of eastern kerogen, as compared to western kerogen, makes its synfuel potential (by Fischer assay) a more sensitive function of the degree of oxidation.

A better yield of oil from oxidized eastern oil shale could be obtained by dissolving away sulfates and other water soluble oxidized materials prior to retorting. The air oxidation of pyrite was demonstrated by SEH, and addition of iron(II) sulfate was shown to reduce assay oil yields. Such observations suggest that combusted shale may not always be a suitable heat transfer agent for atmospheric pressure retorting applications.     

不同介质条件下油页岩热解的初步研究

利用高压釜热解实验装置,对采自民和盆地的油页岩进行全岩、全岩加去离子水和全岩加碱性饱和KCl溶液等3个系列的热解实验研究,并对这3个系列生成的页岩气和页岩油进行对比分析。结果表明：介质的加入有利于液态物的产出,跟油页岩直接加热相比,去离子水的加入使得页岩油的平均产率从83.66 mg/g提高到210.15 mg/g,但是抑制页岩气的生成;而碱性饱和KCl溶液的加入对页岩油和页岩气都有贡献,使得页岩油平均产率从83.66 mg/g提高到186.16 mg/g,页岩气平均产率从7.56 mL/g增大到9.08 mL/g。     

CATALYTIC CRACKING OF RESIDUAL PETROLEUM FRACTIONS

ABSTRACT

Arabian Light crude oil vacuum bottoms has been fractionated into five high-boiling fractions by wiped film evaporation, and the fractions subjected to catalytic cracking in a fixed-fluidized bed using a commercial equilibrium cracking catalyst. Density, aromaticity, and heteroatom content generally increased with boiling point, as did metals content except for vanadium and iron which demonstrated possible bimodal distributions. The cracking response of these fractions showed increasing yields of dry gas and coke, with decreasing gasoline yields, as a function of increasing apparent boiling point as would normally be expected. Surprisingly, however, local maxima were observed for wet gas yield and total conversion, with local minima for cycle oil and slurry yields, in the region of the 1200–1263°F (650–680°C) middle fraction. All fractions showed significant response to cracking, with coke yields generally being the only negative factor observed.     

重油浅度热裂化反应深度对延迟焦化过程的影响

为了提高延迟焦化的液体产品收率,中国石化洛阳工程有限公司对现有工艺进行改进,把浅度热裂化反应和深度热裂化反应有机地结合在一起,开发出了ADCP新工艺。在新研制的减黏-焦化-连续蒸馏联合试验装置上考察了劣质重油浅度热裂化深度对焦化产品分布的影响。结果表明,当重油的减黏率分别为33.03%,52.43%,78.21%时,与常规工艺相比,液体产品收率分别提高了0.48,0.97,1.71百分点,其中轻质油收率分别提高了1.04,1.11,2.19百分点,轻质油收率的提高主要体现在柴油馏分收率提高上,而焦化汽油、柴油和蜡油等产品的性质与常规工艺的产品无明显区别,不会影响各产品的后续加工过程。     

SUPERCRITICAL EXTRACTION OF STUART OIL SHALE

ABSTRACT

This paper describes the recovery of oil from Stuart oil shale using a supercritical extraction technique employing carbon dioxide as solvent. This supercritical technique provides yields superior to comparable retorting techniques. The importance of extraction temperature, pressure, and time has been investigated. In addition, the chemical composition of the oil extracted from the shale is presented. Simulated distillation has been employed to assess the effect of extraction conditions on the quality of the shale oil extracted.     

AN ANALYSIS ON THE COMPOSITIONS OF THE CATALYTIC CRACKING STOCKS FROM SHENBEI OIL

ABSTRACT

Six catalytic cracking stocks from SHENBEI oil, which include recycle stock, coker gatch, sweat oil, residual oil and mixed feed, were analyzed by means of vacuum distillation, n-d-m, E-d-m, mass spectrum and elemental analysis. The fraction compositions, hydrocarbon compositions and element contents of the six catalytic cracking stocks were determined. The effect of compositions of various catalytic stocks on catalytic cracking reaction was discussed. Results show that the gum and asphaltene in the six stocks were lower except residual oil, but saturated hydrocarbon were all high; aromatics in the six stocks except slurry oil and sweat oil were lower, which are suitable for catalytic cracking units. There will be a big potential uses for the residual oil as catalytic stocks.     

CH4/N2气氛对重油热裂解气体产率及组成的影响

延迟焦化工艺中将焦化炉注蒸汽改为注干气,可以避免因注入水蒸气而带来的含硫污水污染。为考察注入干气对装置气体产率及组成的影响,以金陵减渣、济南减渣、青岛减渣为研究对象,在CH4、N2气氛下分别进行热反应实验,分析其热裂解气体产率及组成。结果表明：在反应条件相同时,与N2气氛相比,CH4气氛下的气体产率较低,且裂解气中C1体积分数降低1~2百分点。此外,在反应时间相同时,反应温度升高后,两种气氛下气体产率差值缩小;随油气分压增加,两种气氛下气体产率差值亦缩小。     

OXYGEN AND NITROGEN COMPOUNDS OF ISRAELI SHALE OIL

Abstract

Israeli shale oil was separated into different components, and their composition was studied by means of IR, NMR, and GLC-MS. The yield of the components extracted from the 210-320^°C fraction of the oil was: components soluble in water 0.59, organic acids 0.32, phenols 8.5, and pyridine bases 3.5 wt. %. The phenols content in the total shale oil was found to be 5.4%, that of pyridine bases 3.2%. More than 20 individual compounds were identified in the products of separation, including phenol, methyl phenols, dimethyl phenols, methyl-ethyl phenols, and methyl naphtalenols, 4-propyl pyridine, 2,3,5-trimethyI pyrrol, 2-, and 3-ethyl-3,5-dimelhyi pyrroles, 2-ethyl-4,6-dimethyl pyridine, dimethyl indoles, dimethyl quinolines, uimethyl indoles. Aldehydes, alcohols, ethers Ar-O-R and R-O-R, and esters Ar-COO-R and R-COO-R are not present in the shale oil. NMR spectroscopy resulted in establishing the quantitative distribution of the oil fraction compounds among the principal structures.     

A REACTION KINETICS MODEL OF SHALE OIL UPGRADING IN SUPERCRITICAL WATER

ABSTRACT

A kinetics model of the upgrading of shale oil in supercritical water (SCW) was developed. The model predicts the yields of coke (C)asphalt (A), resid (R), distillate (D) and gas (G), as well as nitrogen (N) removal as a function of batch reaction or plug flow holding time, from the reaction of shale oil in SCW with added catalyst and hydrogen. Mechanistically derived submodels provide the functional dependence of the overall rates of reaction of C, A, R, D and G on process variables. The model can be utilized in two complementary ways. First, it is a quantitative summary of mechanistic insights and hypotheses that suggest further laboratory testing. Second, it can be useful in process engineering calculations.     

ANALYSIS OF OIL SHALE RETORT PRODUCTION STREAM GASES FOR SULFUR SPECIES

ABSTRACT

Analysis of the sulfur species in the production gas stream of oil shale retorts is important for environmental and process development needs. Combined gas chromatography/mass spectrometry and gas chromatography with flame photometric detection have been applied to the qualitative and quantitative analysis of sulfur species in the production gas stream from six oil shale retorting experiments. Hydrogen sulfide was determined to be the most abundant species and represented approximately 95 percent (wt.) of the sulfur present. Minor sulfur species identified and quantitated include carbonyl sulfide, carbon disulfide, methylmercaptan, ethylmercaptan, propylmercaptan, and thiophene. Sulfur dioxide was not identified during any of the retorting experiments studied.

The distribution of these sulfur species from the six retorting experiments is important because it provides a baseline for the design of process control technologies. The importance of the liquid product collection train for control of sulfur emissions was also demonstrated.     

THE EFFECTS OF HIGH PRESSURE ON OIL‐TO‐GAS CRACKING DURING LABORATORY SIMULATION EXPERIMENTS

The effects of high pressures on the yield and kinetics of gas generated by the cracking of crude oil were investigated in laboratory simulation experiments. Samples of a low‐maturity non‐marine oil were recovered from the Paleogene Shahejie Formation in the Dongying depression, Bohai Bay Basin, eastern China. The oils were cracked to gas under different pressure and temperature conditions in an autoclave. Initial temperatures of 300 °C were increased to 650 °C at rates of either 30 or 100 °C/h. Reaction products were analysed at the end of each 50 °C temperature increase. Pressure conditions were either 0.1 MPa (i.e. atmospheric) or 20 MPa. Results show that high pressures inhibit or delay oil‐to‐gas cracking and retard the initiation of the cracking process. The temperature at which oil was cracked and the activation energy of the formation of C_1–5 hydrocarbons increased under high pressure conditions, demonstrating the effects of pressure on the kinetics of the oil‐to‐gas cracking process. High pressures and high temperatures inhibited the conversion of C_2–5 hydrocarbons to methane during secondary cracking. In addition, high pressures retarded the generation of N₂, H₂ and CO during cracking of oil. The presence of water increased the yields of total cracked gas, C_2–5 hydrocarbons and CO₂ in high‐pressure conditions. The simulation results show that CO₂ and C_2–5 hydrocarbons have similar yields during oil‐to‐gas cracking. Using the kinetic parameters determined from the laboratory experiments, the yield and production rate of gas generated during the cracking of oil from Member 4 of the Paleogene Shahejie Formation in the Minfeng‐Lijin sag (Dongying depression) were calculated. The results indicate that only limited volumes of natural gas in this area were derived from the cracking of oil, and that most of the gas was derived from the thermal decomposition of kerogen.     

AIR OXIDATION OF EASTERN OIL SHALES OF KENTUCKY. II. THE EFFECTS OF AMBIENT AUTOXIDATION

Ambient air oxidation leads to lower Fischer assay oil yields and often lower process yields from retorting of eastern oil shales. Slight changes in the kerogen and mineral matter of the oil shale and in its pyrolysis products, both liquid and gaseous, were evident following autoxidation. Experimental observations suggest that the hydrogen deficiency of eastern kerogen, as compared to western kerogen, makes its synfuel potential (by Fischer assay) a more sensitive function of the degree of oxidation.

A better yield of oil from oxidized eastern oil shale could be obtained by dissolving away sulfates and other water soluble oxidized materials prior to retorting. The air oxidation of pyrite was demonstrated by SEH, and addition of iron(II) sulfate was shown to reduce assay oil yields. Such observations suggest that combusted shale may not always be a suitable heat transfer agent for atmospheric pressure retorting applications.     

POLYMER SOLUBILITY THEORY PREDICTS EFFICIENCY OF RESIDUAL OIL EXTRACTION BY POLAR SOLVENTS

ABSTRACT

Light paraffinic solvents (C2 to C7) have traditionally been utilized by the petroleum refining industry to extract oils from crude distillation residua. Extracted oils constitute feedstock to lubricants manufacture and, to a lesser extent, additional cracking stock. More recent literature reveals a growing interest in polar, non-hydrocarbon partially oil-soluble solvents such as alcohols, ketones, and esters of lower carboxylic acids. In this work, articles and patents which report the separation of residua into asphalt and extracted oil by means of polar solvents are briefly reviewed, and the separation performance of same of those solvents is correlated to the solute-solvent interaction parameter (?) in the Flory-Huggins theory of polymer solubility. The three dimensional solubility parameter (δ) approach is followed to estimate ? for the solvents of interest at the appropriate operating conditions. The saturate, aromatic, and polar compounds fractions of a bitumen are characterized by solubility parameters equal to the values of δ of the solvents or mixtures thereof used by the standard ASTM D-2007 chromatographic fractionation of the deasphaltenated oil (DAO). A mean value of ? is found for every DAO-solvent pair, treatment ratio and temperature. For each solvent considered, yields of extracted oil at varying operating conditions (temperature, pressure, solvent /feed ratio) are found to be well correlated to ?, in according with theoretical predictions that the lower a value of ? a solvent has for a given solute, the better it dissolves the solute and the higher the yield.

It is suggested that this type of approach could supply criteria to select solvents and operating conditions for applications requiring high yields (to produce additional cracking stock) or lower yields but high rejection of metals and heteroatoms (e.g. for lube oil bases extraction).     

INFLUENCE OF FEEDSTOCK COMPOSITION ON THE YIELD OF TOTAL CYCLE OIL IN FLUID CATALYTIC CRACKING

ABSTRACT

With a view to gaining an insight into the understanding of the factors responsible for the maximization of the total cycle oil (TCO) in the fluid catalytic cracking of the vacuum gas oils (VGOs) including the one from Bombay High (BH), necessitated by a greater demand for the diesel fuel compared to gasoline, in India, studies have been carried out on three different VGOs in a Xytel Auto Mat II unit over two REY based FCC catalysts differing in their zeolite content using a fixed bed reactor. The fact that the yield of CLO (370^°C+) from BH VGO was much higher than would be expected for a predominantly paraffinic feedstock has led to studying the cracking to compositionally different concentrates isolated from BH VGO and the results are discussed.     

蜡下油/加氢裂化尾油混合原料的裂解性能

以蜡下油/加氢裂化尾油混合物作为蒸汽裂解制乙烯装置原料,利用蒸汽裂解模拟试验装置研究其裂解性能,考察了蜡下油的掺入量、裂解温度和水油质量比对目标烯烃产物收率的影响。蜡下油/加氢裂化尾油混合原料的最佳蒸汽裂解工艺条件为：蜡下油掺入质量分数20%,裂解温度820 ℃,水油质量比0.75,此条件下产物乙烯、丙烯的收率分别为34.3%和14.65%。     

IDENTIFICATION OF THE MINERAL PHASES RESPONSIBLE FOR CEMENTATION OF LURGI SPENT OIL SHALE

ABSTRACT

Very large volumes of solid waste are generated during oil shale retorting. The reclamation and use of these wastes are desirable from an environmental and economical point of view. Two of the primary considerations in the disposal of these wastes are their structural integrity and the leaching of toxics into groundwater.

The spent shale used in this study was generated from oil shale mined from the Green River Formation in the Piceance Basin of western Colorado. The oil shale was processed using the Lurgi-Ruhrgas method (Schmalfeld 1975). The spent shale was packed in the Harvard miniature apparatus (Soiltest 1964) forming columns using three different water contents. Subsequently, the columns were allowed to cure for periods ranging from one day to eight weeks.

Pour types of analyses were performed on the cured columns. X-ray diffraction (XRD), scanning electron microscopy with an energy dispersive X-ray analyzer     

THE PRELIMINARY STUDY ABOUT THE COMPOSITION OF DAQING HEAVY FRACTION OIL

ABSTRACT

The family composition of Daqing heavy fraction oil and the latent content of lubricating oil by mass spectrography and slovent dewaxing methods were determined, and then compared with document data.The change of Daqing heavy distillate is discussed.The results show Daqing crude oil and its distillates have the trend to be heavier,but its heavy distillates are still suitable for catalytic stocks of heavy catalytic cracking and its residuum can be also used for the feed stocks and other wide uses. We hope the analysis results can provide scientific basis for refineries.     

CHEMICAL COMPOSITION OF OIL SHALE II. DEPENDENCE ON THE EXTRACTION PROCESS

ABSTRACT

Eastern and Western U.S. and Australian oil shales were retorted in a fixed-bed, bench-scale retorter, using nitrogen and carbon dioxide as sweep gases. The resulting shale oils were chemically characterized by GC/MS techniques. Shale oils extracted by nitrogen and carbon dioxide retorting processes were found to have different chemical compositions, even when applied to the same oil shale samples. The extraction process dependent nature of shale oils is fully assessed in this paper and the information may be used for comparison among various extraction processes as well as for choosing appropriate upgrading processes for the crude shale oils.