Alternative use of chlorine for sustainable development of chlor-alkali industries in Bangladesh.

Abstract

The chlor-alkali industries produce caustic soda (NaOH), chlorine (Cl2), and hydrogen (H2) as primary products. In 2021, the global chlor-alkali market was valued at $63.2 billion. The article evaluates the global aspects of chlor-alkali industries and prospects for Bangladesh. Caustic soda (NaOH) is a basic chemical used in different industries in Bangladesh. The demand for caustic soda increased swiftly with the rapid extension of RMG sector in Bangladesh. Now the current production capacity of NaOH is 282150 MT/yr (GHCL, ASM, Samuda, Tasnim, SR Chemicals capacity). The NaOH in the country is produced from the membrane cell electrolytic processes which produce 250470MT/yr chlorine as a by-product (GHCL, ASM, Samuda, Tasnim, SR capacity). However, the chlorine consumption is only 68779 MT/yr and thus, the residual chlorine drained through the sewerage as Ca(OCl)Cl, HCl, and NaOCl. This is a great environmental concern for the country. For the sustainable development of this industrial sector, it is urgently needed to utilize the by-products of chlorine. Recently, plastic consumption has been increased substantially in Bangladesh. The article prefigures that a 150,000 MT/y PVC plant can utilize 43% of residual Cl2 of chlor-alkali plants, which would be an economical and environmental milestone for Bangladesh. The residual Cl2 can earn revenue 908 million USD/y, which can be utilized to import ethylene.