Bayer MaterialScience Toluene Diisocyanate (TDI) Plant, Germany

Bayer__Germany TDI

German polymer and plastics producer Bayer MaterialScience constructed a new toluene diisocyanate (TDI) plant at its Chempark site in Dormagen, Germany. The company invested approximately €250m into the facility, which has a TDI production capacity of 300,000t a year.

The TDI facility replaces the company's existing plants in Brunsbüttel and Dormagen. The approval process for the world-scale TDI plant began in the first half of 2010. The construction and operation permit for the plant was granted in January 2013.

The plant was opened in December 2014. It generated up to 1,000 jobs during the construction phase.

Bayer MaterialScience TDI plant background

"The TDI facility replaces the company's existing plants in Brunsbüttel and Dormagen."

Bayer MaterialScience had planned the TDI plant in Dormagen Chempark in December 2008 and presented it for approval to the Cologne regional government. A provisional construction approval was granted to the company in February 2012. The pre-construction works and foundations were laid following the approval.

Dormagen Chempark is a 570ha area, which has been serving the chemical industry since 1917.

The TDI facility is built on the site of a coal-fired power plant, which was demolished. Chempark Dormagen was chosen for the TDI plant after a Europe-wide site selection process. The site has abundant availability of raw materials such as chlorine and TDI precursors. The company built a new reformer for the production of carbon monoxide to facilitate TDI production. Chempark Dormagen also has the infrastructure to process hydrogen, the by-product of carbon monoxide production.

Bayer MaterialScience also plans to increase the raw materials production of its polyurethane rigid foams with expansion of the Brunsbüttel facility. The production of methylene di-para-phenylene isocyanate (MDI) will also be increased at the Brunsbüttel site from 200,000t to 420,000t a year.

Technology at the German toluene diisocyanate facility

Bayer MaterialScience has been producing TDI in Dormagen since 1964. The TDI plant at Chempark uses a new gas phase phosgenation technology developed by the company, which was tested at a pilot plant in 2004 and met the necessary safety standards.

The process is implemented on a larger scale at a plant in Caojing, China, which went on stream in 2011. The patented gas phase phosgenation TDI production process saves 60% of energy compared with traditional processes. It is also environmentally friendly and reduces the solvent consumption by roughly 80%.

TDI plant production processes

Flexible polyurethane foams are produced with the reaction of a polyether polyol with TDI. TDI is produced in a sequence of steps from naphtha, a material obtained from crude oil. Aromatic compounds from naphtha are separated to obtain toluene, the primary hydrocarbon feedstock. Toluene is further nitrated using nitric acid and the reaction produces dinitrotoluene (DNT).

"TDI is an important intermediate in the production of flexible polyurethane foams."

The hydrogenation of DNT produces toluenediamine (TDA), which is then converted to TDI using the phosgenation technology. The gas phase phosgenation process of Bayer MaterialScience includes heating TDA and phosgene at 300°.

The gaseous chemicals produced are reacted and condensed to form liquid TDI. The final step involves the distillation of TDI to remove excess phosgene and the solvent. The distillation phase of the process is claimed to save 40% of energy compared with traditional processes.

The traditional processes involve the reaction of TDI and phosgene in dilute solution forms in a solvent such as orthodichlorobenzene.

Bayer's investment programme and TDI market

Bayer MaterialScience's investment in Dormagen has strengthened the position of the Chempark site as a global TDI technology centre. With the TDI plant, the company could increase its isocyanate production in Europe.

TDI is an important intermediate in the production of flexible polyurethane foams. The foams are used for various modern daily products, such as chairs and seating, cold foam mattresses and cushions of automobiles and office chair seats.

The product is also used for the protective packaging and cushioning of several electronic goods, and for leisure and sports applications. The company expects the demand for TDI to increase in the long-term, thus expanding its position in the global market.

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