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Technical and economic comparison of steam heating and electric heating solutions. Source: China Chemical Machinery Network. In the process of chemical production, steam heating is a traditional method of insulation for the transportation and storage of fluid materials. However, since the steam temperature is much higher than the temperature range required to maintain the material, improper temperature adjustment can lead to overheating of certain areas of the material. Furthermore, the insulation of the condensate pipes accompanying the steam lines is not properly maintained, resulting in frequent freezing and disruptions to production. Especially when transporting and storing materials with strong corrosivity, it can easily cause localized corrosion of the pipes, severely affecting normal production. The self-controlled electric heat tracing system is used in industrial pipeline insulation and anti-freezing technologies; it can accurately maintain the process temperature and completely prevent corrosion of the pipelines caused by local overheating. Abroad, self-controlled electric heat tracing was introduced in the 1980s, and companies such as DuPont, Dow Chemical, BASF, Shell, Exxon, and Hyundai have widely adopted electric heat tracing technology in their facilities. Currently, domestic petrochemical and oil enterprises such as Lanzhou Refinery, Urumqi Petrochemical, Bohai Petroleum, Zhejiang Juhua, and Daqing Chlor-Alkali have also adopted electric heat tracing systems. Heat tracing technology is used for insulation in pipelines with complex transmission routes, those requiring precise temperature control, long-distance transmission pipelines, as well as pipelines that need protection against corrosion and explosions. It offers significant advantages such as superior performance, reliable quality, and a long service life (usually 20 years). However, the use of electric heating technology requires a higher one-time investment. Whether the electric heating solution is still feasible can be determined through further technical and economic analysis, and the answer will become clear then. First, let’s assume that the power supply capacity of the steam boilers and the main substation does not increase. Below, a comparison is made between steam tracing and electric tracing solutions for insulating a 700-m-long process pipeline (to maintain a temperature of 90–110°C) at a large fertilizer plant, with emphasis on economic and social benefits. I. Basic Data (I) Investment Estimation 1 Steam Tracing Scheme (1) Tracing pipeline: Based on the process requirements, a DN20 tracing pipe is selected; the total length of the pipeline is 700 m, with a total weight of 1.59 t (DN20: 2.27 kg/m), and the unit price is 5,000 yuan per ton. Then the material cost is 5000×1.59=7950 yuan ； The installation cost (including installation materials and labor) is 5,570 yuan. (2) For the steam supply pipeline, a DN100 pipeline is used, with a total length of 700m. The material cost is 71,525 yuan, and the installation cost (including installation materials and labor wages) is 28,296 yuan. (3) For the steam supply pipeline insulation, 50 mm thick rock wool is used, with a galvanized iron sheet as the outer protective layer; the total length is 700 m. It is estimated that the material cost is 14,175 yuan, and the installation cost is 30,295 yuan. (4) Steam supply and drain systems include steam supply valves, heat tracing pipe steam supply valves, drain trap isolation valves, drain traps, and drain trap check valves; the cost (mainly for materials) amounts to 1,785 yuan in total. 2 Electric heating scheme (1) Electric heating wires: Domestic electric heating wires with a voltage of 220V are to be used; the price is 50 yuan per meter. For a total length of 700 meters, the cost of the heating wire material will be 700×50 = 35,000 yuan ； The installation cost (mainly labor costs, as it is carried out within the factory premises where conditions are favorable) is calculated at 5 yuan per meter, resulting in 700×5=3500 yuan. (2) Power supply and distribution system, including the distribution room and transmission lines, has a material cost of 110,000 yuan and an installation cost of 4,767 yuan. (II) Operating costs 1: Steam heating solution (1) Steam consumption for pipeline heating: The total steam consumption for heating the process pipelines and for the steam supply pipelines itself is 0.3 t/h. At a cost of 50 yuan per ton of steam, and with 300 operating days per year, the annual steam consumption cost is: 0.3 × 300 × 24 × 50 = 108,000 yuan. (2) Heat tracing pipeline maintenance costs include inspection tours, repairs and upgrades, as well as various other maintenance expenses. Due to the susceptibility of instruments in the fertilizer plant facility to corrosion, the total annual maintenance cost is approximately 30,000 yuan. 2 Electric heat tracing solution: (1) Power consumption – Domestic self-control electric heat tracing wires provide 25 W of heat per meter; with a total pipe length of 700 m, the maximum power supply per hour is 700×25=17500 W. When the pipe temperature reaches the upper limit of the maintenance temperature, the heat generation of the electric heating wire gradually decreases, and its output power also drops; as a result, the actual power consumption of the electric heating system is generally 60% of its rated power. The electricity price is 0.40 yuan per kilowatt-hour; the annual cost for normal electricity consumption is: (17500×7200/1000)×0.40×60% = 30,240 yuan. (2) Maintenance costs: Automatic electric heat tracing requires almost no maintenance; according to regulations, it is only necessary to test the insulation with a megohmmeter once a year. Here, the cost is estimated at 15,000 yuan per year. II. Economic Benefit Analysis: The investment required for the steam heating solution is the same as that for the electric heating solution, but the operating costs are 3.5 times higher for the electric heating solution. The output results of the two options are identical, as both can meet the insulation requirements for the process pipelines; therefore, an analysis can be conducted by comparing the annual value of the costs for the two options. (The economic life of steam heating is taken as 10 years, while that of electric heating is 12 years; the discount rate i=10%). 1. Steam heating option: AC = P(A/P, i, 10) + annual operating costs = 159596×0.16275 + 138000 = 163974 yuan. 2. Electric heating option: AC = P(A/P, i, 12) + annual operating costs = 153267×0.14676 + 45240 = 67733 yuan. Based on the criterion of minimizing the annual cost value, the annual cost value of the electric heating option is approximately 2/5 of that of the steam heating option, making it clearly superior to the former. Through comprehensive comparisons, the economic efficiency of the electric heating solution is significantly better than that of the traditional steam heating solution. III. Social Benefit Analysis: The self-regulating electric heat trace can adjust its heating output based on the temperature of the pipe wall (the medium) itself, making it an energy-saving solution. Steam tracing can only utilize a portion of the thermal energy; a large amount of it is reduced from a high-grade form to a low-grade form and becomes unusable, resulting in wasted energy. According to calculations, the energy consumption ratio of electric heating to steam heating is 1:5.8. Furthermore, since self-controlled electric heat tracing can effectively eliminate problems such as leaks and spills, it improves the manufacturing environment of enterprises.