The decarbonization of industrial operations across the world has been rapidly taking place amidst the urgent actions of governments, industry associations and companies to combat global climate change.
One clear example of these actions can be seen in China. Implemented by the government in 2020 was the dual-carbon policy to continue making notable strides in environmental objectives. The key focus of this policy has been utilizing the latest advancements in technology and process optimization, particularly in energy-intensive industries like petrochemicals, to decarbonize operations whilst improving energy efficiency. Electrification technology is converting this segment to a more sustainable, low-carbon future.
Ethylene “Three Machines”
Ethylene, the fundamental building block of the petrochemical industry, has witnessed a steady rise in production capacity in China. However, the segment faces significant challenges in meeting energy conservation and emission reduction targets. The main reason is that at the heart of ethylene production lies "three machines" - the pyrolysis gas compressor, propylene compressor, and ethylene compressors - which are crucial to production but are high in energy use and carbon emission. Most such machines in use are driven by steam turbines, and many ethylene producers are converting the three machines to be powered by electricity reduce their carbon footprint.
Focusing on cutting fuel consumption and reducing emissions specifically from the ethylene compressor, Shenyang Blower Works (Group) Co., Ltd (SBW). - one of China’s major original equipment manufacturers - delivered an innovative electrical drives and motor solution for a local petrochemical company in collaboration with ABB. This solution aimed to transition the ethylene C2 compressor from steam turbine-driven operation to an innovative variable speed drive and motor system.
The ABB solution completed installation in the last year and is considered a technological breakthrough for ethylene production as it created a more reliable and sophisticated approach to maintain production stability. To further improve the efficiency and reliability of ethylene production, many ethylene manufacturers plan to apply the steam-to-electricity conversion to their pyrolysis gas compressors and propylene compressors in the future.
Mother Nature
Not only is ethylene production energy intensive and expensive, any unexpected shutdown of a compressor at the Chinese producer would not only halt production, but also impact the downstream equipment reliant on it. Ensuring reliability of the drives and motors solution was a crucial aspect of the project brief. In fact, a pre-requisite of the new electric generation system was that it could operate continuously for five years without any unplanned shutdowns!
Further to this challenge, ABB were advised that mother nature could be an influence on continuous operations as the petrochemical installation site is situated near the coast and is prone to frequent lightning strikes. This could often lead to regular power outages and short circuits, hence the potential of significant production losses.
100% Machine Redundancy Configuration
Leveraging extensive expertise in petrochemical applications, ABB provided a comprehensive solution encompassing 100% machine redundancy configuration, anti-voltage sag technology, and exceptional output capabilities, ensuring stable equipment operation and efficient production of the compressor.
Two sets of 34MW 100% capacity LCI drives, utilizing ABB's self-developed high-power thyristor technology, and a 30MW AMS synchronous motor were used in this project. The motor was driven by a drive, while the other drive acts as what is known as a “hot standby”. In the event of an incident that would trigger an unplanned shutdown, the hot standby drive would seamlessly switch to active mode within milliseconds.
The ABB LCI drive adopts a four-quadrant topology, which has a better capability of power loss ride through and resistance to power grid fluctuations. The drive can still continuously provide partial output torque over a long period of time when the power grid voltage instantaneously drops as low as 20%, allowing the driven equipment to operate longer without shutdowns. This solves the problem of frequent lightning strikes that customers face when situated near the coast.
In this project, the maximum working torque of the ethylene compressor is approximately 200kNm. To ensure normal start of the ethylene compressor, the requirement on starting torque of the electrical drive system is higher. The LCI drive can provide 100% starting torque at the velocity of 0. When the operating point reaches 75T/h, the overall efficiency of the VSD-driven system (including LCI drive, filter, input transformer and synchronous motor) can reach 96.03%. This level of performance can greatly improve production efficiency while ensuring smooth operation of customer’s equipment.
Precise Control
Shenyang Blower Works (Group) Co., Ltd. successfully implemented the ABB combined drives and motor solution for its customer, who was able to realize immediate benefits with confidence in the long-term. The steam-to-electricity conversion enables more precise control over the compressor, and thus optimizes energy efficiency, and reduces carbon emissions. The high-reliability solution ensures smooth operation of the equipment and a five-year-long uninterrupted production. Transitioning to a drives-motor system can also effectively reduce equipment maintenance costs and safety risks.
"We are very pleased with the efficient and reliable technical solution provided by ABB,” said Shuai Han, Deputy Director of Petrochemical Complete Set Room of Turbine Design Institute, Shengu Group, adding that "In ethylene production, technology means higher production efficiency and lower carbon emissions. ABB's solution not only perfectly matched our technical requirements but also the unique demands of the customer."
Luping Qi, Lead Business Manager, ABB Motion, China, commented that "ABB drives and high-efficiency motors play a vital role in energy conservation and carbon reduction in various industries and applications, and their energy-saving effects are particularly significant in high-power applications in the petrochemical industry. This case once again underscores how ABB's cutting-edge technology, reliable products, and domain expertise can assist customers in improving production efficiency, reducing costs, and making contributions to saving energy and reducing carbon."
