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Solutions for the Polyurethane Industry

Solutions for the Polyurethane Industry

Oversupplies imbalance hydrochloric acid markets

Chlorine is undoubtedly one of the most important base chemicals. By far the largest share of chlorine produced in industrialized countries today is obtained by chlor-alkali electrolysis. A majority of the world’s chlorine production is used for the chlorination of organic compounds. In such processes only a part of the chlorine remains in the product, while the rest is obtained as hydrogen chloride and as hydrochloric acid - the aqueous solution. For example, in the production of isocyanate by phosgenation of the appropriate amine, a significant portion of reaction chlorine is converted to hydrogen chloride. Due to an expected increase in production capacities a growing dilemma is emerging and a sustainable process solution for the corresponding HCl excess is required.


It is not always possible to find a use for the hydrochloric acid. For instance, a fall in demand for vinyl chloride monomer or polyvinyl chloride may not shore up the supply of hydrochloric acid in direct oxychlorination processes. In general, since the market for hydrochloric acid is saturated and is not growing as it should, the market price for HCl is under pressure. Hence there is often no option to sell either of them. Due to an increase in environmental awareness and sensitivity, the discharge to waste treatment involving additional caustic soda consumption is not a satisfactory solution.

In this instance, it is possible to recover the chlorine from the hydrogen chloride by electrolysis and to recycle it, rather than obtaining the chlorine by chlor-alkali electrolysis or by chlorine transports, which is subject to an array of country-specific restrictions. Therefore hydrochloric acid electrolysis represents an alternative source of chlorine.

Benefits of HCl electrolysis related to the polyurethane industry:

  • Shows general commitment in terms of sustainability, careful use of resources and therefore ecological responsibility.
  • Business is made independent from chlorine and hydrochloric acid prices.
  • Avoids the need to develop traditional chlor-alkali plants with significantly higher investment costs.
  • Interesting for regions with high chlorine demand or excess caustic soda (NaOH); use of a chlor-alkali plant would not be expedient due to further NaOH production in saturated markets.
  • Eliminates the risks of chlorine transports (as a further alternative).
  • No costs related to hydrochloric acid neutralization or disposal.

TDI complex
MDI complex