Condenser downstream

For feeds greater than 5 mol % hydrogen sulfide, but less than 40 mol %, the Recycle Selectox process can be used. In this variation of the Selectox process, a portion of the process gas leaving the condenser downstream of the Selectox reactor is recycled so as to limit the oudet gas temperature from the reactor to >205 C. 

The correct inlet temperature for the deaerator is obtained by mixing the hot condensate downstream of the preheater with cold condensate. This inlet temperature is maintained by a temperature controller around the preheater, which detects the mixed condensate s inlet temperature to the deaerator and is set at a little lower (15°F [8°C]) than the boiling temperature. 

A three-zone furnace (top to bottom are 31, 6", and 3", respectively) was used to maintain isothermal conditions along the reaction zone. Pressure was controlled by a back pressure regulator on the exit stream. A post reactor dropout trap was installed to condense the steam and hydrocarbon condensates. Downstream dry product flow rates were measured by a wet test meter. 

Crude methanol that is condensed downstream of the methanol reactor is separated from unreacted gas in the separator and routed via an expansion drum to the crude methanol distillation. Water and small amount of byproducts formed in the synthesis and contained in the crude methanol are removed by an energy-saving three-column distillation system. 

Closure of a control valve in column overhead line to an air condenser caused rapid condensation downstream of the val and a severe liquid hammer. Control valve was modified so that it would not shut... 

It was found during studies of ammonia synthesis on iron that the incorporation of a condenser downstream of the sample valve in the external circulation loop of the HPLP apparatus (Fig. 7), enabled the system to be run as a flow rather than a batch reactor. This is true for any reaction system where the reactants are more volatile than the products, since the condenser temperature can be adjusted to trap the products almost exclusively, allowing a nearly pure stream of reactants to impinge on the catalyst. In the case of ammonia synthesis, (where, next to the product, nitrogen at a partial pressure of 5 atm was the most condensable species) a slurry of isopentane (— 159.9 °C) was found to be the ideal condenser medium. During a study of rhenium-catalyzed ammonia synthesis the isopentane condenser was switched in periodically to reduce the ammonia partial pressure to below that at which it appeared to poison the catalyst. In this way, the rhenium was able to produce ammonia in excess of the amount usually leading to poisoning. 

A system that is based on NC flow through the reactor core and has NC flow on the secondary side of the SG is, in effect, two coupled NCLs. The secondary loop is the fluid system on the secondary side of the SG, and the ultimate energy sink in that loop is the condenser downstream of the turbines. Of course, the turbines also remove energy from that fluid stream. The SG loop has through-flow with the extraction being the vapor and the injection being the return of the condensate into the secondary side of the SG. 

If regulations governing specific emission limit VOC concentrations to the low ppm range then, of course, vapor fractions such as those illustrated by the above tabulation will not be acceptable. It may, however, still be justified to consider VOC condensation as a precursor to a final abatement device such as an adsorption bed. Removing most of the solvent from a vent stream by condensation, can drastically reduce the size and cost of a downstream cleanup system. 

The low CO leakages of 0.2—0.3 vol % at 200—250°C attainable using LTS converters have allowed the use of downstream methanation to reduce considerably the level of inerts in the make-up gas. The gas at the LTS inlet to the reactor must be over 20°C above its dew point to preclude the possibiUty of capillary condensation of Hquid water within the catalyst. 

These various reactions should be minimized to avoid plugging the catalyst and to prevent fouling of the downstream air preheaters, when these components condense from the gas at the lower temperatures. 

Mercury from cinnabar ore 225 tons ore/day (95% recovery) (2) 18,0 ft. diam, 8 hearth furnaces Furnaces fired on hearths 3 to 7, inclusive retention time of 1,0 hr, furnaces are oil-fired with low-pressure atomizing air burners all air, both primary and secondary, introduced through the burners draft control by Monel cold-gas fans downstream from mercury condensers. 

Lm. The coarseness results from the relatively low power dissipation per mass on distillation trays. This means that it is relatively easy to remove by a device such as a wire mesh pad. Over 50 percent is typically captured by the underside of the next higher tray or by a turn in the piping leaving an evaporator. Conversely, though small on a mass basis, the smaller drops are extremely numerous. On a number basis, more than one-half of the drops in the lower curve are under 5 [Lm. These can sei ve as nuclei for fog condensation in downstream equipment. 

Mineral matter derived from ash constituents of liquid and solid fuels can vaporize and condense as sub-micron-size aerosols. Larger mineral matter fragments are formed from mineral inclusions which melt and resolidify downstream. 

After only 4 months of service, the main condenser at a large fossil utility began to perforate. Initial perforations were due to erosion-corrosion (see Case History 11.5). Small clumps of seed hairs entering the condenser after being blown into the cooling tower were caught on surfaces. The entrapped seed hairs acted as sieves, filtering out small silt and sand particles to form lumps of deposit (Fig. 6.24A and B). Immediately downstream from each deposit mound, an erosion-corrosion pit was found. 

Figure 11.7 illustrates the internal surface at the inlet end of the condenser. Approximately 2 in. (5 cm) of the surface is marked by mutually intersecting depressions and grooves. Areas of the internal surface downstream of this zone are smooth and covered with a thin layer of deposits. This typical case of inlet-end erosion can be eliminated by the techniques discussed earlier in this chapter under Elimination. ... 

In biphase systems velocity of the steam is often 10 times the velocity of the liquid. If condensate waves rise and fill a pipe, a seal is formed with the pressure of the steam behind it (Fig. 2). Since the steam cannot flow through the condensate seal, pressure drops on the downstream side. The condensate seal now becomes a piston accelerated downstream by this pressure differential. As it is driven downstream it picks up more liquid, which adds to the existing mass of the slug, and the velocity increases. 

It is usually not practical or cost effective to cool flue gases to temperatures below ambient values. Condensation scrubbers are generally intended to be used downstream of another scrubber (e.g., a venturi scrubber) which has already removed PM > 1.0 m aerodynamic diameter. 

It is important to note that even if the blowdown is effective in disengaging liquid and vapor, further condensation could occur downstream especially if the vented vapor exits the drum at a temperature above ambient conditions. A proportion of such condensible materials in the blowdown drum vapor release may condense as a result of cooling in the flare header and contact with seal water, and then disengage in the flare seal drum while condensible vapors which are not condensed out at this stage may condense in the flare stack or its inlet line, thus creating the potential for hazardous fallout of burning liquid from the flare. Condensed hydrocarbon in the seal drum can be entrained out with the... 

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