For Braskem, the largest producer of thermoplastics resins in the Americas and the world’s leading biopolymer producer, Siemens Energy designed a cogeneration plant that is fueled with residual process gas with high hydrogen content to reduce water use and CO2 emissions in their Mauá, São Paulo, Brazil facility.
By Roman Elsener
While everybody agrees that we need to shape a new energy future for sustainable development, this transition is easier said than done in many other parts of the world. And there is not just one energy transition – every nation has to find its own, unique resources and approach, adapted to its geography.
Take Brazil, for example. How do you implement a transition from fossil fuels to renewable energy, if some parts of the country do not even have access to electricity yet?
Reducing environmental impacts
This was the question that Braskem, the largest producer of thermoplastics resins in the Americas and the world’s leading biopolymer producer, was faced with. Due to grid quality issues and low efficiency in gas consumption, Brazil has had a track record of production losses and high maintenance costs. Because Braskem serves, among other regions, the sprawling city of São Paulo with more than 12 million inhabitants, the company also needed to reduce its environmental impact by minimizing water use and CO2 emissions.
Partnering with Siemens Energy, Braskem found a solution: The project at the ABC Petrochemical Complex in Mauá will modernize the power generation system in the region, resulting in greater efficiency in production, and at the same time improve the company’s sustainability indicators. Siemens Energy addressed part of Braskem’s challenges, and designed a cogeneration plant that is fueled by residual process gas with high hydrogen content. Braskem’s São Paulo Region Chief Industrial Officer Luís Pazin says: “The modernization of the power generation is part of our Vesta project that will help us meet our sustainability goals by reducing the facility’s overall energy consumption by an amount equivalent to that of a city with 1 million inhabitants.”
With a total investment of around US$110 million from Siemens Energy and Braskem, the project provides a technological update of the system that serves the cracker, the main industrial unit of the petrochemical facility. Here, raw materials for the chemical and plastic sectors are produced. The optimized design leads to an increased efficiency of the ethylene plant.
The two gas turbines and the combined cycle solution from Siemens Energy will generate 38 megawatts of electrical power and provide 160 tons of steam per hour. Braskem estimates that the upgrade project will reduce the cracking unit’s water consumption by 11.4 percent and CO2 emissions by 6.3 percent, mitigating environmental impacts and improving their sustainability target achievement. NOx emissions from the turbines will be low at just 25 parts per million.
For Siemens Energy, the project also offered a chance to achieve a goal set in early 2019. The company committed to gradually increasing the hydrogen capability in gas turbines to at least 20 percent by 2020, and to 100 percent by 2030. With the Braskem project, the first goal will already be surpassed: The two SGT-600 gas turbines involved in the modernization project, with scheduled completion end of 2022, are co-fired with 60 percent hydrogen by volume.
Hydrogen, the missing link?
The ideal scenario of the not-so-distant future: Gas turbines will be powered entirely by “green” hydrogen, which is produced by electrolyzing water with surplus electricity from renewable sources. Åsa Lyckström, Senior Sustainability Strategist at Siemens Energy in Finspång, Sweden, believes that hydrogen may prove to be the missing link to establishing a green and sustainable energy sector.
According to Lyckström, the key to increasing the hydrogen ratio in the fuel mix lies in the burner design. Hydrogen has a very high flame speed, which can damage the burner when the flame is sucked back in. The Siemens Energy team used 3D printing to optimize the DLE (dry low emission) burner design to increase the upstream speed of the fuel and air mixture in order to protect the burner hardware. Because of the process gas stream, the use of hydrogen to provide power is growing. As the oil and gas industries are turning increasingly toward green fuels, this solution may be implemented in various regions of the world. Big refineries and plastics producers are likely to be the next big market.
The energy-as-a-service model
Besides the long-term sustainability of the plant and its high efficiency, the project also demonstrates the advantages of the “energy-as-a-service” approach that covers the entire value chain: Siemens Energy will build, own, and operate the cogeneration plant for 15 years (BOO model). This addresses customer needs in reliable and secure operations while at the same time resulting in CAPEX savings. Siemens Energy’s proven technology – e.g., gas turbines with DLE combustion system and compressors – provides high reliability, availability, and efficiency, and has surpassed initial requirements. This has come without a price increase and while significantly reducing the petrochemical giant’s exposure to grid failures.
“Braskem’s confidence in choosing us as a strategic partner for this challenging project is the result of our technological and operational capacity,” says Christian Schöck, Head of Industrial Applications of Siemens Energy in Brazil. “The innovative BOO model ensures that Braskem focuses its resources on its core business, leaving the necessary investments in engineering, implementation, operation, and maintenance of the cogeneration plant to Siemens Energy.”
Roman Elsener is a news, business, and technology journalist based in New York.
Combined picture credits: Braskem, Siemens Energy