Historically, Ruhr-gebiet's coal, iron ore and steel production plants were all located in the same area. The outstanding feature of Ruhr-gebiet is that it takes coal mining, steel, chemistry, machinery manufacturing and other heavy industries as the core, forming a regional industrial complex with complex departmental structure, close internal relations and high concentration. Ruhr district is an industrial area that started with coal mining. With the comprehensive utilization of coal. Coking, electric power, coal chemical industry and other industries have been developed, which in turn promoted the development of steel and chemical industry. Based on this, machinery manufacturing, especially heavy machinery manufacturing, nitrogen fertilizer industry and building materials industry has emerged. At the same time, light industries that serve a large number of industrial workers, such as clothing, textile and beer industries, have also developed greatly. Since 1950s, due to the gradual increase of oil consumption, the oil refining industry and petrochemical industry in Ruhr area have also developed rapidly. After the 1970s, the electrical and electronic industries have made great progress. At present, Ruhr produces 80% of the country's hard coal and 90% of coke, accounting for 2/3 of the country's steel production capacity. Electricity, sulfuric acid, synthetic rubber, oil refining capacity and military industry all occupy an important position in the country. After the war, when some old industrial areas in the world were seriously declining in coal mining, Ruhr still had strong vitality, which was inseparable from its continuous adjustment of economic structure and departmental structure with the progress of science and technology. Chemical industry is one of the most important industrial sectors in Germany. Germany is the birthplace of modern chemical industry, with a history of 100 years. At present, Germany is the third largest chemical producer in the world, accounting for about 10% of the global chemical turnover. Germany's chemical raw materials changed from coal to oil and natural gas; The department structure has changed from basic chemical industry to basic chemical industry, organic chemical industry and chemical fertilizer. In the organic chemical industry, plastics, synthetic fibers and synthetic rubber are three important sectors, and their output ranks among the top in the world. Ruhr is an important chemical base in Germany and western Europe. Hughes Petrochemical Company is the largest chemical center in Ruhr, with more than 20 chemical plants producing three kinds of synthetic products.