Steam trace

Fluid Tracing Systems Steam tracing is the most common type of industrial pipe tracing. In 1960, over 95 percent of industrial tracing systems were steam traced. By 1995, improvements in electric... 

Half-inch copper tubing is commonly used for steam tracing. Three-eighths-inch tubing is also used, but the effective circuit length is then decreased from 150 feet to about 60 feet. In some corrosive environments, stainless steel tubing is used, and occasionally standard carbon steel pipe (one half inch to one inch) is used as the tracer. 

For some applications, either steam or electricity is simply not available and this makes the decision. It is rarely economic to install a steam boiler just for tracing. Steam tracing is generally considered only when a boiler already exists or is going to be installed for some other primary purpose. Additional electric capacity can be provided in most situations for reasonable costs. It is considerably more expensive to supply steam from a long distance than it is to provide electricity. Unless steam is available close to the pipes being traced, the automatic choice is usually electric tracing. 

For most apphcations, particularly in processing plants, either steam tracing or electric tracing could be used, and the correct choice is dependent on the installed costs and the operating costs of the competing systems. 

Economics of Steam Tracing versus Electric Tracing The... 

The two key variables in the decision to use steam tracing or electric tracing are the temperature at which the pipe must be maintained and the distance to the supply of steam and a source of electricpower. 

High reliability. Many things can go wrong with a steam tracing system but, very few of the potential problems lead to a heat tracing failure. Steam traps fail, but they usually fail in the open position. 

Common usage. Steam tracing has been around for many years and many operators are famihar with the system. Because of this familiarity, failures due to operator error are not very common. 

High in stalled co.sts. The incremental piping required for the steam supply system and the condensate return system must be installed, insulated, and, in the case of the supply system, additional steam traps are often required. The tracer itself is not expensive, but the labor required for installation is relatively high. Studies have shown that steam tracing svstems typically cost from 50 to 150 percent more than a comparable electric tracing system. 

Lower in stalled and operating co.st.s. Most studies have shown that electric tracing is less expensive to install and less expensive to operate. This is true for most apphcations. However, for some applications, the installed costs of steam tracing are equal to or less than electric tracing. 

Temperature control. Even without a thermostat or any control system, an electric tracing system usually provides better temperature control than a steam tracing system. With thermostatic or electronic control, veiy accurate temperature control can be achieved. 

Design requirements. A slightly higher level of design expertise is required for electric tracing than for steam tracing. 

Dust entrained in the exit-gas stream is customarily removed in cyclone cohectors. This dust may be discharged back into the process or separately cohected. For expensive materials or extremely fine particles, bag collectors may follow a cyclone collector, provided fabric temperature stability is not hmiting. When toxic gases or solids are present, the exit gas is at a high temperature, the gas is close to saturation as from a steam-tube diyer, or gas recirculation in a sealed system is involved, wet scrubbers may be used independently or following a cyclone. Cyclones and bag collec tors in diying applications frequently require insulation and steam tracing. The exhaust fan should be located downstream from the cohection system. 

In filter operation, it is essential that the gas be kept above its dew point to avoid water-vapor condensation on the bags and resiilting plugging of the bag pores. However, fabric filters have been used successfully in steam atmospheres, such as those encountered in vacuum diyers. In such cases, the housing is generally steam-traced. 

When winterizing is required, the steam tracing and insulation should include the first 7.5 m of the flare stack above the vapor inlet and also in the case of a drum seal, the vapor line from the seal drum to the flare. Where steam injection to one of the smokeless tips, as shown in Figures 11 B and C is used, then the steam ring should remain outside the top of the flare tip (i.e., not internal). Where severe ambient conditions are encountered then it is recommended that the entire seal drum and flare be insulated in addition to steam tracing and open steam injection at base of flare. 

A similar incident occurred on another furnace when the heat transfer oil froze inside the furnace during unusually cold weather. Outside the furnace, the lines were steam-traced. The operating team decided to thaw the frozen oil by lighting one of the burners... 

If the work as called for on the work order is done in its entirety including steam tracing, insulation, clean up, etc., then the work order should be signed off. The supervisor should return the signed-off work order and the work plan to his supervisor who forwards them to planning. 

Where the acid condensate is corrosive and neutralisers cannot be used, then a condenser of resistant materials has to be employed. However, by steam tracing the lines leading the vapour to the condenser, premature condensation can be avoided (Fig. 9.6) and in consequence a cheaper material may be used. 

Plant piping that can be blocked in with steam tracing on. Sizing... 

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