Environmental protection equipment manufacturing; sales of environmental protection equipment; dust removal technology equipment manufacturing; coal-fired flue gas desulfurization and denitrification equipment manufacturing; furnace, melting furnace, and electric furnace manufacturing; furnace, melting furnace, and electric furnace sales; general equipment manufacturing (excluding special equipment manufacturing); mechanical and electrical equipment manufacturing; sales of mechanical and electrical equipment; distribution switch control equipment manufacturing; sales of distribution switch control equipment; sales of special equipment; metal structure manufacturing; metal structure sales; machinery and equipment sales; general equipment repair; machinery and equipment research and development; industrial engineering design services; general machinery and equipment installation services; environmental protection consulting services (except as otherwise required by laws and regulations, independently operated and managed in accordance with the business license)