Gas Phase Phosgenation Technology: Reduced Energy and Raw-Material Consumption
The gas phase phosgenation technology has revolutionized our TDI production process. Thanks to reduced steam requirements for solvent evaporation and lower yield losses in the TDA to TDI conversion, we achieve significant energy and raw material savings compared to processes based on liquid phase technology. This enables us to meet future requirements in a more sustainable and cost-effective manner.
Revolutionary isocyanates production technology
Our gas phase phosgenation technology is a milestone in the manufacture of isocyanates. Compared to processes based on liquid phase technology, it requires up to 60 percent less energy because much less solvent is circulated in the production unit. Thereby, it contributes to more efficient resource utilization and reduced energy dependency. Furthermore, yield losses over the production process are significantly reduced. The technology is used in the manufacture of isocyanates such as toluene diisocyanate (TDI), which are needed for making flexible foam from polyurethane. The key to this breakthrough? Toluene diamine (TDA) and phosgene react directly in the gas phase at high temperatures, eliminating the need for solvents and enabling fast reaction times.
In this way, a typical large-scale gas phase phosgenation plant with a production volume of 250,000 tons of TDI emits 60,000 tons less carbon dioxide per year than a conventional process. Thanks to the gas phase phosgenation technology, the TDI yield can also be enhanced as the reactants undergo faster conversion, resulting in reduced byproduct formation.
Continuous technology enhancement
We have continuously enhanced the gas phase phosgenation technology since implementation. Both TDI gas phase phosgenation plants in Dormagen (Germany) and Shanghai (China) implemented significant process improvements in 2017, achieving up to 25% reduction in distillation residues and an additional 20% reduction in energy consumption compared to the original plant configuration.
This represents just the beginning of our optimization efforts, with current projects targeting even greater energy reductions.
