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Low international oil price, advance in renewable energy technology, development of energy storage technology and strict environmental regulations have presented encumbrance and opportunity for the current oil shale project development. Oil shale industry is at critical stage and facing challenges from competitive conventional energy, clean renewable energy and more strict environmental regulations. Through an innovative design of the oil shale pyrolysis process model by utilizing a developed new advanced technology, the oil shale project could improve its resilience and sustainability with excellent social and economic performance.This paper investigated the shale oil production process in terms of technology selection, utilization of resource, energy efficiency, oil yield, and mining to improve the resilience of oil shale project economic performance facing lower oil price. Innovative design options for the oil shale production process model were discussed from the following aspects: 1) itemized cost analysis and comparison of shale oil production technologies; 2) development of a new oil shale pyrolysis process model with combination of the existing vertical retort process (VRP) and horizontal rotary-kiln retort process (HRRP) technologies to improve the oil shale process economic gain; 3) discussion of innovative design options to improve the economic performance of the process by utilizing the current new advanced energy storage technology. Investigation of the applicability of the energy storage system (ESS) to the oil shale project was carried out with a sensitivity analysis of its cost-revenue.

In this paper, an oil shale comprehensive utilization system based on Huadian-type retorting technique is constructed for producing shale oil, electricity, heat and construction materials. The system presented in this work aims at increasing resource utilization efficiency, improving process efficacy and reducing pollutant emission. Shale oil as a valuable product can be obtained by retorting. Meanwhile, during this process, the byproducts, retort- ing gas and semi-coke, not only can be used to provide sufficient energy for retorting, but can also be combusted efficiently in sequent subsystems for electricity generation and district heating. Moreover, the discharged shale ash can be used to produce construction materials. The proposed system is modeled and evaluated by the process simulation software Aspen Plus. The simulation results indicate that the scheme of oil shale comprehensive utilization has several advantages over oil shale retorting or combustion merely, and about 0.161 million t/a shale oil and 123.82 MW power can be produced in this system. Also, increasing the mass fraction of oil shale for retorting would exert a positive impact on the system's economics, which is especially important considering the rising oil prices.

The uncertainty about the current prices of petroleum, its growing worldwide consumption and limited availability have motivated many countries rich in oil shale resource to explore more efficient retorting technologies to widely produce and use shale oil as an alternative. On the basis of the retorting technology progress and the characteristics of oil shale, this paper recommends a combined system with a fluidized bed (FB) reactor for retorting oil shale and a circulating fluidized bed (CFB) boiler for burning semicoke and fuel gases, realizing the effective and clean use of oil shale. The FB retort and CFB boiler are arranged side-by-side, and hot circulating ash and semicoke will be conveyed from one side to the other. Both CFB circulating ash and fuel gases as fluidizing gases of the FB retort are proposed to be heat carriers together, transferring the combustion heat from the CFB to oil shale in the FB retort. Retorting temperature, heat capacity distribution of heat carriers and parameter optimization of the whole system are further discussed as key issues.

The paper focuses on investigating the impact of mineral compo- nents of Meihekou oil shale on the conversion of organic carbon from the oil shale into shale oil. A number of leaching operations were performed and each product formed in the bioleaching process was analyzed. The analysis showed that the bioleaching technology used is best for oil shale conversion. The yield of shale oil was from 8.3% to 11.2%, and approximately 8.4% of extra shale oil was obtained. During bioleaching a lot of micropores were generated in oil shale, which is favorable to transfer heat from the outside into the inside of the bioleached oil shale sample. Therefore, more shale oil could be obtained through the micropores rapidly, which may avoid shale oil from cracking into shale gas. Finally, bioleaching contributes to the pro- duction of more shale oil.

(c) Unconventional Oil&Gas Key Laboratory of Petrochina, 065007 Hebei, China Abstract. Oil shale resource is an important supplement to conventional oil and gas in China. Thermal in situ retorting processes for producing hydro- carbons from oil shale have been utilized recently. Based on the mechanical analysis of the process of oil shale retorting, for an efficient production of shale oil and gas at least two requirements should be met. Firstly, the expulsion pressure of oil and gas from shale needs to be lower than the breakdown pressure of the overburden interval, to keep the produced oil and gas confined. Secondly, the expulsion pressure of oil and gas should be higher than the breakdown pressure of the shale reservoir to enable the development of more fractures to allow oil and gas to flow. The expulsion pressure of oil and gas from shale is primarily dominated by temperature which means that a vertical or horizontal heater delivery borehole needs place at a proper depth. The higher the heating temperature for in situ shale oil production is, the deeper and thicker the oil shale reservoir should be.

The production of oil shale gas from kukersite oil shale is a successfully implemented industrial process. The above process was urgently introduced in the former Soviet Union due to the energy crisis after World War II. During the second half of the 20th century the oil shale processing technologies and material sciences developed very fast, and with no doubt, whenever the need for the production of oil shale gas emerges today, we have valuable experience in this field. An economic analysis must give the answer to the profitability of this kind of production. The environmental issues are also important, first of all those related to the residue of organic matter in the solid waste from oil shale pyrolysis.

The effect of co-firing of biomass fuels with oil shale on combustion was investigated. Thermogravimetric analysis and differential scanning calorimetry were the tools used to perform the investigation. Since the combustion of biomass is highly exothermic, biomass fuels can serve as an appropriate fuel feedstock. Biomass fuels producing much volatile matter and containing less cellulose are good candidates for co-firing with oil shale. The biomass samples used in the study were hazelnut shell, wheat bran, poplar, and miscanthus. Co-firing of biomass/oil shale blends was performed using different biomass ratios (10, 20 and 50% by weight).

Laboratory level autoclave pyrolysis experiments of Chinese Liushuhe oil shale have been conducted at different heating temperatures and pressures to simulate underground in-situ thermal conversion. Effects of water and metallic ions on oil shale pyrolysis have been investigated. In the presence of water, pyrolysis of oil shale generates thermal bitumen as an intermediate product at first, then pyrolysis of bitumen produces shale oil and gas takes place. With increasing temperature, the yields of shale oil and gas increase gradually, while the yield of bitumen initially increases (max. at 300 °C) and then decreases. Compared with the modified Fisher Assay, auto- clave pyrolysis temperature of simulated experiment was 100 °C lower when reaching the same conversion level of oil shale. Analysis of the gas chromato- graphy-mass spectrometry (GC-MS) showed that main chemical compounds of the light fraction in shale oil are phenols and benzenes. The analyses of gas chromatography showed high percentage of carbon dioxide and low per- centage of hydrocarbons. The research results could provide theoretical information for underground in-situ thermal conversion of oil shale.

Production of shale oil yields a significant quantity of by-product gas that can have considerable value. The by-product, oil shale retort gas (OSRG), constitutes about ¼ of the energy input of the shale that is processed in a Galoter-based retort. The desirability of producing separate products from OSRG is confirmed. Even one single component - propylene - has a potential market value of up to US$250 million per year if produced on the scale that Eesti Energia ( EE) is proposing to develop its oil shale project in Utah, USA. Used in its aggregate state as a simple fuel in a power plant, the same amount of OSRG has only about 5% of that value.

Utilization of the semi-coke collected from oil shale retorts is very important and advantageous. Due to the inflammable property, co-combustion of semicoke with other good quality solid fuels could be effectual. In this research, a kinetic study of the combustion of oil shale semi-coke (SC) mixed with bituminous coal (C) was carried out by thermogravimetric analysis at different heating rates. Popescu's method was applied to analyze the kinetic mechanisms of combustion of oil shale semi-coke, bituminous coal and their blends; Flynn-Wall-Ozawa method was employed to determine the activation energies of those combustion reactions. Based on the obtained results, it was concluded that three-dimensional diffusion model could be implemented either for the combustion process of oil shale semi-coke or for bituminous coal while for their blends the model of random nucleation and growth could be applied. The activation energies of oil shale semi-coke and the blends of semi-coke and bituminous coal decreased in the beginning, and then increased during the combustion process. Activation energies of the blends decreased with increasing amount of bituminous coal.

In this paper, the basic principle and features of the process carried out in a Sanjiang(SJ)-type rectangular pilot-scale retort have been described. The suitability of the SJ retort for processing oil shale from Yaojie (YJ) county, Gansu province, China was investigated to find optimal condi- tions for an effective recovery of shale oil. The pyrolysis of lump YJ oil shale was carried out in the SJ pilot retort with a daily processing capacity of 24 tons of oil shale. It was found that the heat value of the pyrolysis gas pro- duced from YJ oil shale was sufficient to provide the heat needed for retort- ing. The pyrolysis temperature fluctuated between 550 and 700 o C, with an average of 610 o C. The results of the study demonstrate that the shale oil yield from YJ oil shale is high, accounting for about 85% vs. Fisher assay. The shale oil consists mainly of diesel and heavy fractions, and the spent shale is of high calorific value.

In this paper the country-specific carbon emission factors for the by-products from oil shale thermal processing (generator gas, semi-coke gas and semicoke) for different technologies are presented. Today these emission factors have still not been determined in Estonia. As the shale oil production will increase significantly in the future, major attention should be paid to the oil shale production-related emission factors.

Emissions of fine particulates of grade PM2.5 and PM10 from different oil shale (OS) power plant (PP) boilers were studied. Pulverized (PF) and circulating fluidized-bed (CFB) boilers burning oil shale, biomass and retort gas were investigated. Particle emissions from OS boilers were found to be very fine. Over 90% of emitted particulate matter was in the size range of PM10 and 40-60% under the size of 2.5 μm. Distribution of fine particles by size was found to be depending on OS firing mode (PF or CFB). At CFB firing mode the share of the finest fraction PM2.5 was higher than that at PF firing mode. The distribution varied at the same type of different PF boilers, depending on the efficiency of boiler flue gas cleaning system and value of total suspended particulates’ emission (TSP).

Scotland had a history of full-scale shale oil production from 1850-1962 and was a key developer of many of the technologies still used in modern-day, above ground retorting processes. The central Scotland oil shale field is only a tenth the size of the Estonian oil shale field (194 km 2 ) with 7 main oil bearing seams. Remaining resources are calculated at 1,100 million tonnes. The Scottish shale-oil industry mainly produced oil for petrol, lighting and lubricating. In addition extensive use was made of the waste products, like ammonia, that were created in retorting process. The spent shale was typically about 75% of the weight of the raw shale and was tipped onto shale bings (spoil heaps) up to 95 metres high; much of this spoil was also utilised in a range of by-products.

The most substantial feature of shale oil and power cogeneration is the technology that uses the high-temperature solid phase from the ash separator of a circulating fluidised-bed (CFB) boiler as the heat carrier in the rotating drum reactor in oil shale retorting equipment rather than high-temperature ash from a single-purpose built-in semi-coke burning furnace. Retort products generated in the rotating drum reactor are separated from semi-coke in the separator and canalised into the condensing and cleaning equipment. Semi-coke is transported into the CFB furnace. All co-products generated in this technological process, such as phenol water, drying agent containing oil shale particles etc., are defused in the furnace of the CFB boiler. The application of such technology makes it possible to minimise the dangerous waste of shale oil production and guarantee the maximum use of oil shale energy.

The basic parameters of oil shale quality are heating value and grain-size composition. Heating value can vary considerably within the location in a deposit and depends on concretions and limestone content. Grain-size distribution and heating value depend directly on mining technology: breakage, transporting and processing. Energy distribution when using different technologies was determined. New boilers of oil shale power plants and oil retorts require a relatively constant quality of raw materials and fuel. The possibility of improving oil shale separation was investigated.

Pyrolysis of Chinese Huadian oil shale using carrier gases N-2 and CO2 was investigated by TG-FTIR method. The results show that carrier gas does not change weight loss or mechanism of pyrolysis, while decomposition of carbonates in the mineral part can be retarded by CO2. This regulation was found to be in accordance with kinetic analytical results. The pyrolysis of oil shale in a fixed bed from room temperature to 500 degrees C at heating rate of 10-20 C/min was also investigated. Hydrocarbons are the main components in shale oil, and hydrocarbon derivatives concentrate in the number of C-16-C-23 by CO2 retorting, the chains being longer than those of hydrocarbons obtained by N-2 retorting.

This paper describes the research on fluidized-bed retorting of pulverized oil shale on pilot-plant scale (daily processing capacity of 50 tonnes oil shale). Chinese Yi Lan pulverized oil shale 0–3 mm was used as feed. Oil shale is fed and pyrolyzed in a fluidized-bed pyrolyzer, where it is heated to about 500 °C by recycled hot shale ash coming from a fluidized-bed combustor. Nitrogen, coal gas or superheated steam is used as fluidizing agent in the pyrolyzer. The shale char formed from oil shale in the pyrolyzer mixed with shale ash is recirculated to the fluidized-bed combustor, where it is burnt by incoming air (as fluidizing agent) to form shale ash at about 700 °C and is recycled to the pyrolyzer as hot solid heat carrier. The mixture of shale oil vapors and pyrolysis gas, formed from oil shale, mixed with steam or other fluidizing agent coming from the pyrolyzer, comes through two cyclones for removal of entrained dust and is washed by warm water to condense heavy shale oil, then goes to cooler for recovery of light shale oil. The total shale oil yield accounts for 80% of Fischer assay. The properties of shale oil and pyrolysis gas are analyzed.

Transformation and distribution of sulfur compounds in fossil fuel thermal processing depends on the bonding forms of sulfur in the specific feed-stock, thermal processing conditions and the technology used. This paper is focused on oil shale semicoking in a pilot-scale solid heat carrier retort (Galoter process) where oil shale is heated by means of mixing with ash from retorted shale combustion. The effect of out-burning conditions of the solid semicoking residue in the technological regeneration furnace on transformation and distribution of sulfur in retorting products is shown for two types of Estonian oil shales – dictyonema argillite and kukersite oil shale. These oil shales used differ significantly in their sulfur composition (total sulfur and sulfur bonding forms present) and mineral matter content.

The effect of water vapor on the yield and composition of products formed at thermal treatment of Bulgarian oil shale kerogen at atmospheric pressure has been studied. It was found that water steam reacts with oil shale organic matter significantly affecting the yield and composition of liquid and gaseous products. As for the yield of liquid products, it is about 20% higher than the yield obtained at Fischer Assay. The yield of semicoke is about 10% less. Liquid products formed in the presence of water vapor are richer in aromatic and aliphatic hydrocarbons among which long-chain paraffins with up to 33 carbon atoms predominate.

In this study, applicability of oil production from oil shales by steam recovery in a three-dimensional (3-D) reservoir model was investigated. Four different oil shale samples from several fields (Seyitomer, Beypazaro, Himmeto lu and Hatolda ) were used. 3-D steam injection experiments showed that steam injection was insufficient to drive oil production for the oil shale samples studied, and it was concluded that the steam injection process is not feasible in these oil shale fields.