Technology

Historical Context

SRJET Technology is named after Slurry Bed, Residue Hydrocracking, and  JET Fuel (SRJET). 

Sinopec Biojet Fuel (SAF) Production Technology (SRJET) was independently developed by Sinopec Research Institute of Petroleum Processing Co., Ltd. over a decade and has independent intellectual property rights. In 2011, industrial demonstration production was successfully carried out at the Zhenhai Refining and Chemical Company. After airworthiness certification organized by the Civil Aviation Administration of China, industrially produced biojet fuel was used for the first domestic commercial flight in 2015 and the first transoceanic international flight in 2017, respectively^[1].

Technical Features

1. Integrated optimization of the hydrogenation process: Designed for feedstock with high fat content, addressing issues like heat release during operation to ensure stable processing.

2. Enhanced hydrogen protection technology: Uses multi-level protection forms (pores, granules, and hydrogen-rich gradients) to improve fluidity and prevent catalyst bed pressure drops or deactivation.

3. Stable catalytic hydrogenation: Employs water-stable catalysts to prevent rapid deactivation in the presence of water during operation.

4. Precious metal-based catalysts: Efficient conversion with high jet fuel yield and low gas loss^[2].

Feedstock

Bio-oils constitute the feedstock for the process, examples of which include^[2]:

• Used Cooking Oil (UCO)
• Animal and Vegetable Oils and Fats
• Microalgae Oil
• Fatty Acid Methyl Esters

Processing Steps

Key processing steps include^[3]:

1. Pretreatment: The raw materials are pretreated to remove impurities such as moisture, solid particles, metal ions, etc., to ensure the smooth progress of subsequent processes.
    
2. Hydrogenation: This is the core step in the production of bio-jet fuel. Since bio-oil contains high oxygen content, reaching 10%-15%, while petroleum-based jet fuel contains less than 0.1%, it is necessary to convert the oxygen molecules in the oil into water through hydrogenation reaction, while removing various impurities such as sulfur, chlorine, and metal elements. The special catalysts and processes independently developed by Sinopec can effectively control the temperature rise of the reactor and ensure the stability and efficiency of the refining process.
    
3. Isomerization and cracking: After hydrodeoxygenation, the product needs to be further isomerized and cracked to adjust the molecular structure to make it closer to the characteristics of traditional aviation kerosene, including boiling point range, density, viscosity, etc.
    
4. Refining and Blending: Finally, biojet fuel needs to be refined to remove any remaining impurities and then blended with traditional petroleum-based jet fuel to meet the performance requirements of aviation fuel, such as freezing point, flash point, calorific value, etc.

Key Indicators

Key indicators include^[2]:

• Using waste oils as feedstock, SRJET achieves:

  • Bio-jet fuel yield: 55%-60%

  • Total yield of bio-jet fuel and renewable diesel: 70%

  • Gas loss rate: <10%

• Bio-jet fuel meets ASTM D7566 standards for sustainable aviation fuels.

Economic Benefits

Economic benefits include^[2]:

• Current feedstock procurement costs: 10,000–11,500 yuan/ton

• Bio-jet fuel selling price: ~25,000 yuan/ton

• Significant economic advantages due to the high value-added nature of the product.

Commercial Deployment

The SRJET technology has been industrialized at Sinopec's Zhenhai Refinery with a capacity of 100,000 tons/year of bio-jet fuel production. The product meets China's aviation fuel standards (GB6537-2018), achieving an overall carbon reduction rate of 74.3%. It has supplied SAF for Airbus A320 aircraft assembly in Tianjin, making Sinopec a major supplier in Asia^[2].

Zhenhai Refining and Chemical's 100,000 ton/year bio-jet fuel industrial production unit^[1].

References

1. Xiaoyanzi, 13^th Jun 2022, The first in China! Sinopec's independently developed bio-jet fuel hydrogenation unit was successfully started up, Jingyan Chemical Platform.
2. Sinopec Research Institute of Petroleum Processing Co., Ltd., 8^th Nov 2023, Bio-Jet Fuel Production (SRJET) Technology, China Petrochemical Corporation (Sinopec) SRJET Technology
3. Yang Jian, 21st Nov 2024, What specific processes are used in Sinopec's independently developed biojet fuel production technology (SRJET)?, Zhuanlan Zhihu.