circular economy, Covestro’s new chlorine production plant Deacon II

Covestro’s new chlorine production plant Deacon II starts up in Shanghai

Copied to clipboard
A further step towards circular economy
The new Deacon II plant at Covestro Integrated Site Shanghai ©Covestro
  • Facility converts by-products into chlorine required for production of functional materials
  • Carbon footprint reduced with highly efficient process for recycling hydrogen chloride
The hydrogen chloride oxidation plant Deacon II at Covestro Integrated Site Shanghai (CISS) has officially started up recently, as part of efforts to further reduce energy consumption and costs, improve production efficiency, and contribute to Covestro’s strategic goal of advancing sustainability and the circular economy.

In the Deacon process, hydrogen chloride, a by-product in the production of isocyanates, is converted into chlorine with great efficiency. Chlorine is then reused as a raw material in production. The highly efficient process is based on catalytic oxidation of hydrogen chloride using oxygen. In comparison with conventional processes, it can reduce energy consumption by more than half.

Covestro started the construction of Deacon I, the world’s first industrial scale chlorine recycling plant, at CISS in November 2008, and it was put into operation in mid-2011. At the end of 2018, Deacon II broke ground as a “smart copy” – the two Deacon plants are of the same size and leverage the same technology, operation procedures and equipment, thus resulting in synergies for plant operators. On top of that, previous upgrades in the elder twin Deacon I were incorporated into Deacon II, which started operation in February 2021.

Additional chlorine supply, less carbon footprint

The maximum capacity and efficiency of the Deacon II plant is increased by about 20% compared to Deacon I. Among other measures, the heat generated during the process is fed back into the production cycle in the form of steam, so the recycling can be achieved with the lowest possible CO2 footprint. The start of the new Deacon II plant will provide Covestro an additional chlorine production of 160,000 metric tons per year with lower cost and lower energy consumption. With Deacon, 98% of the hydrogen chlorine generated during the production of isocyanates is recycled at the Shanghai site. As a result, the corresponding CO2 emissions fall from over 150,000 to just over 9,000 metric tons per year compared with external supply. That is equivalent to the emissions from about 73,000 cars per year.

Dr. Yun Chen, Senior Vice President and Head of Covestro Integrated Site Shanghai, said, “Covestro is committed to fostering the circular economy and sustainable production, including actively exploring innovative methods for energy-saving chlorine production. The Deacon II plant leverages advanced, reliable, and sustainable process to convert by-products in the production process into high-quality raw materials required for the production of functional materials, thus forming a circular system, and greatly reducing environmental footprint. The start of the plant is a milestone for CISS in actively promoting sustainable production.”

Covestro has since 2001 invested more than EUR 3.5 billion into building the Shanghai integrated site, which is the company’s largest site worldwide and is celebrating its 20th anniversary this year. In 2018, the Shanghai site was granted the National Green Factory certificate by the Ministry of Industry and Information Technology for its continuous efforts in using innovative processes that ensure greater sustainability in manufacturing, becoming the first of its kind inside the Shanghai Chemical Industry Park.

About Covestro:

With 2020 sales of EUR 10.7 billion, Covestro is among the world’s leading polymer companies. Business activities are focused on the manufacture of high-tech polymer materials and the development of innovative, sustainable solutions for products used in many areas of daily life. In doing so, Covestro is fully committed to the circular economy. The main industries served are the automotive and transportation industries, construction, furniture and wood processing, as well as electrical, electronics, and household appliances industries. Other sectors include sports and leisure, cosmetics, health and the chemical industry itself. At the end of 2020, Covestro has 33 production sites worldwide and employs approximately 16,500 people (calculated as full-time equivalents).

This press release is available at Please acknowledge the source of any pictures used.

Find more information at and

Forward-looking statements
This news release may contain forward-looking statements based on current assumptions and forecasts made by Covestro AG. Various known and unknown risks, uncertainties and other factors could lead to material differences between the actual future results, financial situation, development or performance of the company and the estimates given here. These factors include those discussed in Covestro’s public reports which are available at The company assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.