Development of a Coupling Oil Shale Retorting Process of Gas and Solid Heat Carrier Technologies

Oil shale is one of the most potential alternative resources for crude oil. Its exploration and exploitation are of increasing interest. In China, oil shale is mainly used by retorting technology. Fushun-type retorting technology, a typical gas heat carrier retorting technology, accounts for the largest proportion in China. However, this retorting technology is only applicable of coarse oil shale particles bigger than 10 mm in diameter. A lot of fine oil shale particles are discarded, resulting in waste of resources. Besides, this technology is criticized by low economic benefit. The main objective of this paper is to develop a coupling oil shale retorting process. The novel process can use fine oil shale particles as the raw materials of solid heat carrier retort to produce more shale oil. The novel process is modeled, and next, the simulation is carried out to build its mass and energy balance. From the techno-economic point of view, the advantages of the novel process are demonstrated by comparison to the traditional Fushun-type oil shale retorting process. Results indicate that the novel process is promising because coupling the two retorting process can increase the shale oil production from 13.86 to 17.34 t/h, the exergy efficiency from 32.46 to 38.01%, and the return on investment from 11.04 to 18.23%

Development of a Coke Oven Gas Assisted Coal to Ethylene Glycol Process for High Techno-Economic Performance and Low Emission

Developing a coal to ethylene glycol (CtEG) process is of great interest to many countries, especially China. However, because the hydrogen to carbon ratio of the coal-gasified gas is far less than the desired value, the CtEG process suffers from high CO₂ emission and wastes precious carbon resources. At the same, most coke oven gas (COG) is discharged directly or used as fuel, resulting in a waste of resources, serious environmental pollution, and economic loss. To develop efficient and clean utilization of coal and COG resources, we propose a novel coke oven gas assisted coal to ethylene glycol (CaCtEG) process. The proposed process introduces the hydrogen-rich COG to adjust the hydrogen to carbon ratio and reduce CO₂ emission by integrating a dry methane reforming unit. Key operational parameters are investigated and optimized based on the established mathematical model. The advantages of the process are studied by a detailed techno-economic analysis. Results show that, compared with the conventional CtEG process, the CaCtEG process is promising since it increases the carbon element and exergy efficiency by 18.35% and 10.59%. The CO₂ emission ratio of the proposed process is reduced from 2.58 t/t-EG to 0.44 t/t-EG. From an economic point of view, the CaCtEG process can save production costs by 5.11% and increase the internal rate of return by 3.41%. The capital investment, however, is slightly increased because of the two additional units

Integrated Process of Coke-Oven Gas Tri-Reforming and Coal Gasification to Methanol with High Carbon Utilization and Energy Efficiency

The hydrogen to carbon (H/C) ratio of coal gasified gas in the range 0.2–1.0, far less than the desired value for the coal to methanol process. Therefore, a water gas shift unit is needed to raise the H/C ratio, which results in a great deal of CO₂ emission and carbon resource waste. At the same time, there is 7 × 10¹⁰ m³ coke-oven gas (COG) produced in coke plants annually in China. The hydrogen-rich COG consists of 60% hydrogen and 26% methane. However, a massive amount of COG is utilized as fuel or discharged directly into the air, which makes a waste of precious hydrogen resources and causes serious environmental pollution. This paper proposes an integrated process of coke-oven gas and coal gasification to methanol, in which a tri-reforming reaction is used to convert methane and CO₂ to syngas. The carbon utilization and energy efficiency of the new process increase about 25% and 10%, whereas CO₂ emission declines by 44% in comparison to the conventional coal to methanol process

Development of an Oil Shale Retorting Process Integrated with Chemical Looping for Hydrogen Production

The increasing demand of crude oil is in conflict with the shortage of supply, forcing many countries to seek for alternative energy resources. Oil shale is welcomed by many countries that are short of conventional fossil fuels. China mainly uses retorting technology for shale oil production. Fushun-type oil shale retorting technology takes the largest share in the oil shale industry. However, this technology is always criticized by its unsatisfactory economic performance. It is caused by many reasons. One of the most important problems is the inefficient utilization of retorting gas. The idea of our research is to utilize the retorting gas to produce higher valued chemicals. For this, chemical looping technology is integrated into the retorting process for hydrogen production. This proposed process is modeled and simulated to build its mass and energy balance. Techno-economic analysis is conducted and compared to the analysis of the Fushun-type oil shale retorting process. The results show that the exergy destruction of the proposed process is 235.62 MW, much lower than that of the conventional process, 274.76 MW. In addition, the proposed process is less dependent on shale oil price. Two shale oil price scenarios have been investigated, showing that the proposed process can still be of benefit, 10.62% ROI, at low shale oil price, while the ROI of the conventional process is −2.07%

Viable Alternative Prospective Option for Liquid Methanol Industry’s Long-Term and Cost-Effective Development: CO₂ to Methanol Conversion and Ethylene Glycol Coproduction

The CO2-to-methanol (CTM) process can realize the recycling of carbon resources and mitigate the global greenhouse effect. However, the low CO2 conversion rate is a consequence of the thermodynamic equilibrium, which restricts the direct hydrogenation of CO2 to methanol (CTMI). Furthermore, there exists a state of kinetic competition between the reaction that produces methanol and the reaction that reverses the water–gas shift, which leads to the low selectivity of methanol. To solve these problems, a new process of indirect hydrogenation of CO2 to methanol and the coproduction of ethylene glycol (CTMII) was proposed in this paper. The steady state modeling, energy integration, and technoeconomic evaluation of the new process were carried out. It was found that the carbon and hydrogen utilization rates of the CTMII process were 98.95% and 98.63%, respectively, corresponding to increases of 2.99% and 34.21%, respectively, compared to those of the CTMI process. The selectivities of methanol and ethylene glycol in the CTMII process are 47.44% and 52.56%, respectively. Under the current economic conditions (0.35 CNY/kWh electricity, 1.8 CNY/m3 natural gas, 5000 CNY/t ethylene glycol, and 17.5 CNY/kg H2), the production cost of the CTMII process was 2572 CNY/t-CH3OH, 38.82% lower than that of the CTMI process. The net present value was calculated, and a sensitivity analysis of the relationship between hydrogen and production costs was performed. When the H2 price dropped to 13.6 CNY/kg, the product cost of CTMII could compete with that of the coal-to-methanol process, showing great economic potential for the future. This study presented a novel approach for the utilization of CO2 resources and broadened the path for green and low-carbon production of methanol