Water removal from loop

Methanol Synthesis. AH commercial methanol processes employ a synthesis loop, and Figure 6 shows a typical example as part of the overall process flow sheet. This configuration overcomes equiUbtium conversion limitations at typical catalyst operating conditions as shown in Figure 1. A recycle system that gives high overall conversions is feasible because product methanol and water can be removed from the loop by condensation. 

Material removed from the water by stripping in this manner can also be concentrated by trapping in a loop immersed in a cooling bath. The usual cooling baths are liquid nitrogen or solid carbon dioxide with or without an... 

Drizo A variation of the glycol process for removing water vapor from natural gas, in which the water is removed from the glycol by stripping with a hydrocarbon solvent, typically a mixture of pentanes and heavier aliphatic hydrocarbons. The process also removes aromatic hydrocarbons. Last traces of water are removed from the triethylene glycol by stripping with toluene in a separate, closed loop. Invented in 1966 by J. C. Arnold, R. L. Pearce, and H. G. Scholten at the Dow Chemical Company. Twenty units were operating in 1990. U.S. Patent 3,349,544. 

Solids. Treatment of mustard agents by the SILVER II process results in the precipitation of silver chloride, which, if not removed, could cause cell plugging. This precipitate is removed from the main circuit in a slurry underflow from hydrocyclones in the anolyte feed stream circuit. Subsequently, this slurry is dewatered in a centrifuge to approximately 50 weight percent AgCl, with the remainder of the slurry consisting of water, nitric acid, silver nitrate, and trace amounts of other materials in the anolyte loop. 

A sample of raw river water was spiked with two loopfuls of Klebsiella oxtyoca. 100 ml aliquots of this of this spiked water solution were brought to 0.05 ppm, 0.1 ppm, 0.2 ppm, 0.5 ppm, or 1.0 ppm of inventive silver composition. After an incubation of 5-60 minutes, the samples were membrane filtered. The filter was rinsed with approximately 100 ml sterile water. The filters were aseptically removed from the filter housing and placed on coliform nutrient agar plates. The plates were incubated under growth conditions for 24 hours and counted. 

After final cooling by air or cooling water, the synthesis gas is compressed (6) and sent to the synthesis loop (7). The synthesis loop is comprised of a straight-tubed boiling water reactor, which is more efficient than adiabatic reactors. Reaction heat is removed from the reactor by generating MP steam. This steam is used for stripping of process condensate and thereafter as process steam. Preheating the... 

Armed with the thermodynamic fundamentals of heat management, we now take a closer look at the unit operation control loops for heat exchangers. We start with utility exchangers. These are used when heat is supplied to, or removed from, the process. Examples are steam-heated reboilers, electric heaters, fuel-fired furnaces, water-cooled condensers, and refrigerated coolers. 

It is energetically advantageous to add the purified synthesis gas at a point in the synthesis loop where it can flow directly to the synthesis converter (see Section 4.5.1). For this reason water and traces of carbon dioxide must be removed from the makeup gas downstream of methanation. This is accomplished by passing the makeup gas through molecular sieve adsorbers, which can be positioned on the suction side or in an intermediate-pressure stage of the synthesis gas compressor. 

Following plant start-up a number of studies and plant observation programs were carried out. These resulted in making some physical modification to the plant such as elimination of dead legs in the reaction section where polymerization could be enhanced. At the same time, operational control aspects were modified such that corrections to the operating conditions could be made before the reaction become unstable. Furthermore, efficient means of heat removal from the reactor were implemented i.e. chilled water cooling loop. 

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