Steam Trap Specification

Steam traps are automatic mechanisms that remove low heat-content air and condensate from the steam delivery system. The lack of steam traps or use of traps that fail to function properly leads to a gradual decline in heat-transfer efficiency, waterlogged heat exchangers, and water hammer (which may in turn result in ruptured pipes). When adequate maintenance of steam traps is neglected, this ultimately leads to a serious overall loss of operating efficiency. There are various types of steam traps, each designed for a specific function. Some common variations are discussed in the following sections. 

I was once working in a refinery that could not meet the flash-point specification for its diesel product. Flash point is the temperature at which a hydrocarbon will ignite, when exposed to an open flame. To raise the flash point of diesel oil, it is steam-stripped, to remove the lighter, more combustible components. I noticed that I could drain water from the bottom of the steam supply line to the diesel-oil stripper. I then screwed a steam trap, on to the i/4-in drain valve, on the steam supply line. The stripper bottoms temperature increased by 35°F, and the flash temperature of the diesel product increased from 120 to 175°F,... 

Determine the condensate load. The first step in selecting a steam trap for any type of equipment is determination of the condensate load. Use the following general procedure. a. Solid materials in autoclaves, retorts, and sterilizers. How much condensate is formed when 2000 lb of solid material with a specific heat of 1.0 is processed in 15 min at 240°F by 25-psig steam from an initial temperature of 60°F in an insulated steel retort ... 

In order to compensate for these variations in operating conditions, the designer uses a capacity safety factor to increase the calculated condensate load. This safety factor should be selected with care. One short-cut method that should be avoided sizing steam traps to equal line size. This practice is never a substitute for analyzing process conditions it invariably leads to specification of the wrong size steam trap. 

Each specific steam trap has a finite, relatively narrow range that it can handle effectively. For example, an inverted-bucket trap designed for up to 15-psi service will fail to operate at pressures above that value. An inverted-bucket trap designed for 125-psi service will operate at lower pressures, but its capacity is so diminished that it may back up the system with unvented condensate. Therefore, it is critical to select a steam trap designed to handle the application s pressure, capacity, and size requirements. 

Steam traps arc designed fc r a relatively constant volume, pressure, and condensate load. Operating practices should attempt to maintain these parameters as much as possible. Actual operating practices are determined by the process system, rather than the trap selected for a specific system. 

Description Three RAM processes are available to remove arsenic (RAM I) arsenic, mercury and lead (RAM II) and arsenic, mercury and sulfur from liquid hydrocarbons (RAM III). Described above is the RAM II process. Feed is heated by exchange with reactor effluent and steam (1). It is then hydrolyzed in the first catalytic reactor (2) in which organometallic mercury compounds are converted to elemental mercury, and organic arsenic compounds are converted to arsenic-metal complexes and trapped in the bed. Lead, if any, is also trapped on the bed. The second reactor (3) contains a specific mercury-trapping mass. There is no release of the contaminants to the environment, and spent catalyst and trapping material can be disposed of in an environmentally acceptable manner. 

The specification of the reboiler HeatX model in Aspen Plus is a hot stream outlet vapor fraction of zero (liquid condensate leaving from the stream trap). When the file is exported into Aspen Dynamics, the default condition in the reboiler is a fixed steam-side pressure. 

In the same year, our group in Lausanne published first results from a similar instrument which was equipped with an electrospray ion source for producing closed-shell biomolecular ions, the first demonstrations of which were the measurement of the UV spectra of cold, protmiated aromatic amino acids, tryptophan [46], tyrosine [46, 122], and phenylalanine [122]. Spectroscopic detection is achieved by measuring the small percentage of parent ions that fragment subsequent to UV absorption. The internal temperature of the ions was estimated to be 11-16 K from an analysis of the intensity of hot band transitions of low frequency vibrational modes. If the temperatures achieved in buffer-gas cooled ion traps are low enough and the spectra sufficiently simple, one can often resolve UV absorption spectra for different stable cOTiformers of the molecule [122]. In this case, one can use the IR-UV double resonance techniques so profitably employed in supersonic molecular beam studies [91,123-128] to measure conformer-specific infrared spectra, and this was applied by Steams et al. to both individual amino acids [129] as well as peptides with up to 12 amino acid residues [130]. Subsequent improvements to the Lausanne machine (Fig. 7) included the addition of an ion funnel to... 

Fig. 6. Hie effect of vanaKiium on the selectivities of steam deactivated ocmneccial caitalysts witdi and without a vanadium trap, (a) MAT specific oolos yields and (b) MAT hydrogen yield.

Fig. 7. Ihe effect of vanadium on the MAT specific coke yields of steam deactivated commercial catalysts containing increasing levels of vanadium trap.

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