A Sustainable Integration Approach of Chlor-Alkali Industries for the Production of PVC and Clean Fuel Hydrogen: Prospects and Bangladesh Perspectives

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. The current production capacity of NaOH from the chlor-alkali industries in Bangladesh is around 282,150 metric tons/year (MT/y). The by-products, chlorine (Cl2) of 250,470 MT/y and hydrogen (H2) of 7055 MT/y, are produced domestically. The local demand of Cl2 is 68,779 MT/y. However, there are no systematic utilizations of the residual Cl2 and vented H2, which threatens the sustainability of the chlor-alkali industries. The article prefigures that a 150,000 MT/y PVC plant can utilize 45.2 % of residual Cl2 of chlor-alkali plants, which would be an economical and environmental milestone for Bangladesh. The residual Cl2 can earn revenue of 908 million USD/y, which can be utilized to import ethylene. For the sustainable utilization of vented H2, production of H2O2, fuel cell electric vehicle (FCEV) and H2 fuel-cell-based power plant are the feasible solutions. Thus, for the long-term growth of the chlor-alkali industry in Bangladesh and other developing countries, systematic utilization of Cl2 and H2 is the only feasible solution.

Recent advances in energy-efficient chlorine production via HCl electrolysis

“…48,49 Accretion of H 2 and Cl 2 gas occurs in the cathodic compartment corroding the membrane. 50 Sluggish reaction kinetics resulting in poor conversion of HCl to chlorine.…”

Study on the removal of SO42−and Ca2+from potassium chloride brineviaa method combining calcium chloride and carbon dioxide

“…The freezing method can effectively remove SO 4 2À only when the content is over 30 g L À1 , and it is restricted by high energy consumption and the requirement of a large working area. 1 In comparison, chemical precipitation is a relatively economical method for removing SO 4 2À and is widely applied in the industry. The most common precipitating agent used is barium chloride, 9 which can rapidly react with SO 4 2À in solution to generate a sediment of barium sulfate.…”

“…The chlor-alkali industry is one of the most basic chemical industries, and its products are widely used in many industries, such as paper making, textiles, and water treatment. 1 The core of the chlor-alkali industry is the electrolysis of sodium or potassium chloride, which is often affected by the content of SO 4 2− in raw chlor-alkali brine. Excess SO 4 2− will lead to the side reaction of anodic oxygen evolution during the electrolysis process; therefore, it is crucial to effectively remove SO 4 2− to avoid high energy consumption.…”

“…The freezing method can effectively remove SO 4 2− only when the content is over 30 g L −1 , and it is restricted by high energy consumption and the requirement of a large working area. 1 In comparison, chemical precipitation is a relatively economical method for removing SO 4 2− and is widely applied in the industry.…”

Green synthesis and characterization of binary, ternary, and quaternary Ti/MMO anodes for chlorine and oxygen evolution reactions

“…Electrolysis of a concentrated sodium chloride (brine) solution, which produces chlorine gas and sodium hydroxide, is one of the most common industrial electrolytic processes worldwide 1 . Chlorine is essential for water disinfection and is used to assemble polyvinyl chloride (PVC), as well as in the production of a variety of other chlorinated polymers, solvents, and specialized compounds 2 . In the meantime, sodium hydroxide is widely used in the pulp and paper industry, the extraction of aluminum from bauxite, and the manufacture of chemicals 3 .…”