【Major Industrial Equipment in the Chemical Industry】350 – Hangyang’s first million-ton-class expander in China was successfully put into use at Qilu Petrochemical’s Second Plant

The Hangyang expander provided design, manufacturing, and commissioning services for the refrigeration expanders used in carbon dioxide purification and liquefaction systems within CCUS projects. This unit operates in the mode of an expansion generator set; its primary working medium is chemical process exhaust gas that is a mixture of carbon dioxide, nitrogen, hydrogen, and a small amount of carbon monoxide. As the gas expands, its pressure and temperature decrease, thereby achieving a cooling effect. At the same time, the energy contained in the gas is recovered and converted into electrical energy through a generator, which is then fed into the power grid to generate benefits.

“The use of expanders in large-scale carbon dioxide capture, utilization, and storage should serve as a precedent, providing guidance for future CCUS projects of even larger scale. ”Xiao Hongyuan explained that various difficulties had to be overcome during the design and manufacture of this expander. At an outlet pressure and a temperature of minus 56°C, carbon dioxide undergoes phase changes, potentially existing in gas, liquid, and solid states, which can have an adverse effect on the long-term safe and stable operation of the expander. To this end, Hangyang overcame the challenges related to controlling the temperature at the expansion turbine outlet during the design process; it managed to complete the delivery in just four months. This marked the first time such technology was used in a million-ton-scale CCUS project in China, contributing to the achievement of low-carbon, safe, environmentally friendly, and efficient operations in industrial facilities.

【Major Equipment in the Chemical Equipment Industry】349-Ethanol Project: Methanol Gas Separation Unit and Hydrogen Compressor https://bbs.hcbbs.com/thread-3358521-1-1.html (Source: Hua Hai Chuan Liu – Haichuan Chemical Forum Website)

Explosion protection and rotor dynamics design are challenging. The medium also contains flammable and explosive gases such as hydrogen and carbon monoxide; therefore, the entire unit must be designed in accordance with the explosion-proof standards for hydrogen environments. At the same time, the expander seal requires a dry gas seal with an extremely low leakage rate, which poses greater challenges to the rotor dynamics design of the entire unit. 03 Designing for variable operating conditions is difficult. This purification and liquefaction unit uses a mixed feed of exhaust gases from two chemical processing units, and the operating conditions can vary widely; it is necessary to achieve expansion refrigeration across a range of 40%-105%. 04 Although the expansion unit is not large, it has a vast number of control and monitoring points, requiring very high standards for control. Functions such as the monitoring and control interlocks of the expander need to be integrated into the Integrated Turbine Compressor Control Technique (ITCC) system, where sequential control for starting and stopping is carried out, as well as control of the unit’s performance. This system also monitors the process parameters of the main and auxiliary equipment, tracks the displacement, temperature, and vibration of the unit’s bearings, and provides continuous monitoring and protection for the unit’s auxiliary systems; it also issues alarms or commands for shutdown.