7/24/2023 0 Comments Heating tracingViscous fluids become extremely difficult, and sometimes impossible, to pump if they cool below a certain temperature. In oil refineries, petroleum processing plants, and any industry handling heavy liquids, there are often times when it is necessary to heat a product before it can be moved. They are generally used for the steam tracing of oil, gas, or chemical lines that must be kept from freezing. These valves sense the temperature of the air around the actuator and stroke the valve open as temperature approaches the set point. For the majority of applications, however, the choice falls between steam tracing and electrical tracing.Ī hybrid of the temperature regulator is referred to as an Ambient Sensing Steam Tracing Valve. Hot water is often used in the food industry where relatively low temperatures are desirable, such as keeping chocolate in a molten state, and hot oils are sometimes used in chemical processing especially when high temperatures are required. The choice of tracing method will usually lie between steam, hot liquid or electrical tracing. (The heat load calculation methods are beyond the scope of this discussion). The amount of heat energy required to maintain the desired temperatures may influence the type of tracing to be used. In the chemical process industry a multitude of products such as asphalt and sulfur can only be moved through pipe lines at specific temperatures. For example, many oil and fat lines have to be heat traced. Of equal importance is the tracing of process pipelines which carry liquids that can be pumped only at temperatures that are well above the freezing temperature of water. Anti-frost protection for water pipelines is needed both in the processing industries as well as in commercial and domestic buildings. Trace heating is a vital element in the reliable operation of pipe lines, storage and process vessels throughout the process industry. Here are some points and simplified piping schematics to consider. This article is intended to provide insights into inherent practical advantages of steam which may have been overlooked in the past. These promotional articles have generally been based on strictly economical considerations which represent only part of the story. A valid case can probably be made for either, depending on the method being promoted by the particular author. Many articles have been written concerning the advantages of steam over electricity (or vice versa) for tracing applications. The following excerpts from Fluid Controls Institute (FCI) Tech Sheet #ST 102 identify the benefits of Steam Tracing vs. Other specialized electric tracing systems make use of impedance, induction, and skin conduction effects to generate and transfer heat. When current flows through the resistive elements, heat is produced in proportion to the square of the current and the resistance of the elements to current flow. The majority of commercial electric heat-tracing systems in use today are of the resistive type and take the form of cables placed on the pipe. In general, heating of tracing fluids can be provided by waste heat from a process stream, burning of fossil fuels, steam, or electricity.Įlectric heat-tracing systems convert electric power to heat and transfer it to the pipe and its contained fluid. If an organic heat-transfer fluid is employed, it is returned to a heat exchanger for reheating and re circulation. Steam is universally available and non-toxic. Only a small quantity is required for a large heating load and it can heat a line quickly, condense at constant temperature, and flow to the point of use without pumping. Steam’s high latent heat from vaporization is ideal for heat-transfer applications. A number of desirable features made steam the original heat-tracing system of choice to maintain process temperature and provide freeze protection. If steam is the tracing fluid, the condensate is either returned to the boiler or dumped. The fluid is usually contained in a tube or a small pipe attached to the pipe being traced. Fluid heat-tracing systems utilize heating media at elevated temperatures to transfer heat to a pipeline. Heat-tracing systems can be divided into two broad categories, fluid and electric.
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