Vinyl chloride (vinyl chloride monomer) referred to as VCM. In industry, vinyl chloride is an important raw material for the synthesis of polyvinyl chloride (PVC). Polyvinyl chloride is one of the five general-purpose resins in synthetic resin. It is also the pillar product of the continuous development of the chlor-alkali industry and one of the important products to promote the development of the petrochemical industry. With the rapid development of our society, the production of PVC and consumption in various industries have grown rapidly. In 1995, my country's PVC output was 1.374 million tons, and its apparent consumption was 1.87 million tons. In 2009, China's total PVC output was 9.16 million tons, of which polyvinyl chloride production using calcium carbide method was 5.8 million tons, accounting for 63.3% of the total output. Faced with such an alarming number, we know that the demand for vinyl chloride, an irreplaceable synthetic raw material, will increase dramatically. China's PVC industry is currently in a period of rapid development, and the demand for technological progress, energy saving and emission reduction, and cleaner production is very urgent. The PVC industry will always maintain a rapid and stable development trend for a long period of time in the future, and the vinyl chloride market has great potential for tapping. How to produce vinyl chloride more quickly, effectively, safely, and environmentally has become an important magic weapon to seize the market, and has become the research focus of major companies, universities, and scientific research institutions. 

 Taking the production process of calcium carbide method as the main line is a major feature of the development of China's PVC industry in the early 21st century. Adopting this characteristic development model that is different from that of other countries and regions is due to China's "oil-deficient, gas-poor, and coal-rich" energy structure, at the same time, the ethylene process route is difficult to meet the needs of the comprehensive and healthy development of the domestic PVC industry .   The development of the calcium carbide process PVC industry is in line with the current domestic energy structure and the objective requirements of the domestic PVC and the entire chlor-alkali industry. The healthy and rapid growth of the calcium carbide process PVC industry with Chinese characteristics not only lays the foundation for the leap-forward development of China's chlor-alkali industry in the past 5 or 6 years, but also will promote the international competitiveness of China's PVC and the entire chlor-alkali industry in the future.       

 Carbide method is used to produce PVC catalysts, and almost all of them use mercury chloride catalysts in China. At present, the average consumption of mercury chloride catalyst per ton of polyvinyl chloride in China is about 1.2 kilograms (based on the average content of mercury chloride of about 11%).  The production of polyvinyl chloride using calcium carbide method in China in 2009 is about 5.8 million tons, the calcium carbide method polyvinyl chloride industry in China used about 6,960 tons of mercury catalyst, about 766 tons of mercury chloride, and about 566 tons of mercury. The waste mercury catalyst is the main mercury-containing solid waste in production (mercury chloride content is about 4%). Although the enterprise has adopted effective prevention and control measures in the subsequent mercury-containing waste collection and treatment, there are still a small amount of Mercury emissions that enter the environment. How to effectively solve the problems of mercury pollution caused by large mercury consumption and mercury discharge in the calcium carbide industry is a severe test from the environmental protection faced by industry enterprises. The problem of mercury pollution also faces enormous international pressure. The core of the current international community’s discussion on mercury is to restrict or even phase out the use and extraction of mercury; in the future, China will have serious problems of mercury supply and demand reduction and mercury waste disposal in export trade, and it will also face the implementation of international conventions in the future. If the mercury pollution is not paid attention to and the control and management of it is not strengthened, it will cause a passive situation. Facing huge international pressure, domestic pressure is not optimistic. As resources of the most country’s mercury mines have been depleted, the price of mercury has soared. With the EU’s comprehensive ban on the export of mercury from July 2011 and the closure of major mercury mines, only Kyrgyzstan and China currently have mercury mines that are currently being mined internationally. The price of mercury will continue to rise with mercury resources tightening. The continuous rise will also seriously affect the survival of mercury-consuming industries. Facing such an urgent domestic and foreign situation, we must thoroughly solve the problems of mercury use and pollution. Our first task is to rely on technological development to create efficient and environmentally friendly mercury-free catalysts to replace traditional mercury chloride catalysts and low-mercury catalysts, to fundamentally solve the problem of mercury pollution in catalysts, and to create Craftsmanship with the lowest pollution coefficient per unit and the least energy consumption. Saving energy and reducing consumption, and eliminating pollution are the inevitable roads for the development of PVC. The development of mercury-free catalysts is urgent and imperative.