Sodium hydroxide (NaOH), also known as caustic soda or caustic soda, is a basic chemical raw material widely used in paper making, detergents, oil and gas, waste treatment, textiles, water treatment, food processing and other industries12. The main production method of sodium hydroxide is the chlor-alkali method, which involves electrolysis of salt water solution in an electrolytic cell to generate sodium hydroxide, chlorine and hydrogen. Sodium hydroxide machinery refers to the equipment used to produce sodium hydroxide by the chlor-alkali method, including a system composed of electrolytic cells, electrodes, power supplies, filters, coolers, storage tanks, pumps, pipelines, instruments, etc.
The development history of sodium hydroxide machinery can be traced back to the 19th century, when mercury electrode method and diaphragm method were mainly used to produce sodium hydroxide. The disadvantages of these two methods are that the mercury electrode method will cause mercury pollution, and the diaphragm method will cause the sodium hydroxide to contain more salt and chloride, affecting product quality. In order to solve these problems, the technology of membrane production of sodium hydroxide began to appear in the mid-20th century, that is, using a special ion exchange membrane in the electrolytic cell to separate the anode and cathode, so that sodium hydroxide and chlorine gas can pass from the cathode and anode respectively. outflow, improving the purity of the product and the utilization of electrical energy. At present, the membrane method has become the mainstream technology of sodium hydroxide machinery, accounting for more than 80% of the global sodium hydroxide production capacity.
The market demand for sodium hydroxide machinery mainly depends on the consumption and price of sodium hydroxide, as well as the utilization of chlorine and hydrogen by-products. According to the global sodium hydroxide market report, global sodium hydroxide consumption was approximately 82 million tons in 2019 and is expected to grow to 97 million tons by 2025, with an average annual growth rate of 2.8%. The Asia-Pacific region is the largest consumer market for sodium hydroxide, accounting for more than 45% of global consumption, mainly due to the development of paper, textile, chemical and other industries in the region.
Europe and North America are secondary consumer markets for sodium hydroxide, accounting for about 25% of global consumption, mainly due to demand from the detergent, oil and gas industries in the region. The price of sodium hydroxide is affected by raw salt, electricity, transportation and other factors, and generally shows cyclical fluctuations4. Chlorine and hydrogen are by-products in the production process of sodium hydroxide, and their utilization will also affect the market demand for sodium hydroxide machinery. Chlorine is mainly used to produce polyvinyl chloride (PVC), bleach, pesticides and other products, while hydrogen is mainly used to produce ammonia, methanol, fuel cells and other products.
The future development trend of sodium hydroxide machinery is mainly to improve production efficiency, reduce energy consumption, reduce environmental pollution and develop new application fields. In order to achieve these goals, the technological innovation of sodium hydroxide machinery mainly focuses on the following aspects:
Optimize the design of the electrolytic cell to improve current density and electrolysis efficiency, reduce electrode corrosion and dirt accumulation, and extend the service life of the electrolytic cell.
Improve the performance of ion exchange membrane, reduce resistance and permeability, improve selectivity and stability, reduce concentration loss of sodium hydroxide and reverse osmosis of chlorine.
Utilize renewable energy and waste heat to generate electricity, reduce electricity costs and carbon emissions, and improve energy efficiency and environmental friendliness.
Develop new electrolytic media, such as ionic liquids, solvent mixtures, solid electrolytes, etc., to replace traditional salt water solutions, reduce salt consumption and wastewater discharge, and improve the safety and flexibility of electrolysis.
Expand new application fields of sodium hydroxide, such as biomass conversion, carbon capture and utilization, metal extraction and recovery, nanomaterial preparation, etc., to increase the added value and market potential of sodium hydroxide.
