Steam traps Installation

Steam traps are installed in condensate, mechanical return systems and are a frequently overlooked item for reducing operating costs. Large industrial process plants typically have many hundreds of steam traps installed to recover low-energy condensate and remove (potentially corrosive) air and carbon dioxide. 

Steam traps install trap below condensate exit (or with a water seal if the trap is elevated), use a strainer before all traps, use a check valve for bucket traps. Slant pipes to the trap. Use a downstream check valve for each trap discharging to a common header. Pipe diameter > trap inlet pipe diameter. Prefer to install auxiliary trap in parallel instead of a bypass. Do not group thermodynamic traps because of their sensitivity to downstream conditions. 

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. 

Water hammer can also occur in steam mains, condensate return lines, and heat exchange equipment where steam entrapment can take place (Fig. I). A coil constructed and installed as shown here, except with just a steam trap at the outlet, permits steam from the control valve to be directed through the center tube(s) first. Steam then gets into the return header before the top and bottom tubes are filled with steam. Consequently, these top and bottom tubes are fed with steam from both ends. Waves of condensate are moved toward each other from both ends, and steam can be trapped between the waves. 

The use of oversized steam traps giving very generous safety factors does not ensure safe and effective steam line drainage. A number of points must be considered if a satisfactory installation is to be achieved, including ... 

In anything but the smallest installations the flow of steam from the boiler into the cold pipes at start-up (while the boiler pressure is still very low) will lead to excessive carry-over of boiler water with the steam. Such carryover may be enough to overload a separator at the boiler take-off point or its steam trap (Figure 22.5). Great care... 

Steam lines from the boiler should always drain away from the boiler crown value to prevent condensate building up against the valve. Careless opening of this valve to allow steam to pass when the line is flooded can result in splitting the valve and pipework. If the steam line rises from the crown valve a tee trap must be installed and fitted with a steam trap and drain valve. The drain valve must be operated to check that the steam line is clear of water before the crown valve is opened. 

Coil boilers often use automatic, TDS-controlled solenoid valves to control BD. They are installed following the steam separator and steam trap. 

Condensation occurs constantly in steam pipes, and steam traps are installed to separate the steam from the condensate. In long steam-pipe runs most of the carbon dioxide remains in the steam phase, although if only a single neutralizing amine with a low DR is used, much of the amine will be present in the condensate. The result is that the amine feed quickly becomes depleted, and further down the steam/condensate pipe the pH level becomes progressively lower. 

Steam system. Clean steam is used for all equipment that comes into contact with containers, solution, or closures prior to product assembly. Pure steam is produced by a generator fed by deionized water. Steam traps are installed to collect condensate when necessary. The quality of pure steam condensate is the same as water for injection. The quality of pure steam is monitored through a quality analyzer system that measures the conductivity of condensed pure steam. 

The problem in Mobile was resolved by installing a small steam fdter on the steam line to the jet. This filter extracts moisture from the steam, and blows it out through a steam trap. 

Condensate Return Systems. In a process plant, steam traps are used to drain and return condensate. Given proper application and continuous maintenance, these can operate with minimal steam leakage. Correct installation is also important (12). 

For steam applications, it is generally neither recommended nor usual to use manifolds or headers, but they can be utilised if proper consideration is given to all aspects of the design and installation, and proper draining is provided via, for instance, automatic steam traps. On the other hand, considering current environmental or safety requirements, a lot of process vapours are manifolded into flare headers before being flared off or otherwise treated and disposed of. 

Undersized steam traps, dirty traps, and incorrectly installed traps should be avoided. Oversized traps can cause water hammer. 

To overcome this problem, a submerged condensate pot is often installed instead of the steam trap (Fig. 17.le) as described earlier (item 5 above). An alternative remedy is replacing the steam trap by a level condensate pot (Fig. 17.1/). By varying the level control set point, the surface in the reboiler can be adjusted so that the reboiler operates at a pressure high enough to ensure condensate removal at all times without a pump. Note that the bottom of this drum is located below the bottom of the condensing side of the reboiler (189) otherwise, "dry reboiler operation at high rates will not be possible, and reboiler capacity will be reduced. 

Reduce steam condensate draining by installing steam traps reduce flashing of steam condensate in condensate headers by condensate cooling separating flash steam install additional steam condensate recovery systems... 

The use of a stethoscope will help to give an early warning of defective bearings and inefficient steam traps. The judicious installation of manometers can indicate when the efficiency of extraction systems or filters has fallen off and help in advancing the cleaning of the respective duct systems, or replacement of filter packs. 

It is important to know that steam traps should not be sized based on pipe size. A common problem is poorly sized traps that cause premature failure through excessive cycles and wear on internal parts as well as excessive steam leaks. Therefore, steam traps are selected primarily on duty second, on duty variation for transient cases and third, on equipment requirement (Kenny, 1989). Proper installation and maintenance together with regular vendor service can maintain good steam trap performance and long life. 

Opened bypass valves, opened steam-bleed valves, steam leaking out of steam traps, visible waste condensate, and system water hammers are the signs that steam consuming equipment are not optimal. An opened bypass valve usually indicates equipment limitation, so operators open bypass valves to compensate. Bleeders are often visible at turbines and in steam jacket tracing applications. This could be a sign that operators may not have confidence in the installed CDL, so they bleed valuable steam to achieve the required operation. 

Steam traps, or the strainers that protect them, are often blocked by the accumulation of rust and dirt and it is a good practice to install a by-pass valve which enables the condensate to be removed while the strainer is being cleaned see Fig. 7.1. It is most important to ensure that the by-pass valve is closed except while the strainer or trap is being overhauled. 

The best steam trap will not function correctly if the piping to and from it is not properly designed and installed. Many factors are important and some will be discussed. 

Has the steam trap been properly selected, sized, and installed ... 

November 9, 1987 - A leak of approximately 760 L (200 gal) of sulfuric acid occurred during transfer operations. This leak was cleaned up at the time. On December 4, 1987, it was noticed that the trench was open to the soil at the location where the leak occurred. This open area was found to be a dry well installed in 1986 when the trench was upgraded. The dry well was installed for steam trap drainage, not for containment of acid spills. An estimated 57 to 114 L (15 to 30 gal) of sulfuric acid was released to the ground (WHC 1987e). An unknown amount of contaminated soil was removed. 

When properly selected, installed, and maintained, steam traps are relatively trouble-free and highly efficient. The critical factors that affect efficiency include capacity and pressure ratings, steam quality, mechanical damage, and calibration. 

Installation of steam traps is relatively straightforward. As long as they are properly sized, the only installation imperative is that they are plumb. If the trap is tilted or cocked, the bucket, float, or thermal valve will not operate properly. In addition, a nonplumb installation may prevent the condensate chamber from fully discharging accumulated Uquids. 

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