Condensate Stabilizer Design

HETP for a 2-in. slotted metal ring in a condensate stabilizer is about 36 in. This is slightly more than a typical tray design, which would require 34 in. (1.4 trays X 24-in. tray spacing) for one theoretical plate or stage. 

A gas-processing plant, as described in Chapter 9, is designed to recover ethane, propane, butane, and other natural gas liquids from the gas stream. A condensate stabilizer also recovers some portion of these liquids. The colder the temperature of the gas leaving the overhead condenser in a reflux stabilizer, or the colder the feed stream in a cold-feed stabilizer, and the higher the pressure in the tower, the greater the recovery of these components as liquids. Indeed, any stabilization process that leads to recovery of more molecules in the final liquid product is removing those molecules from the gas stream. In this sense, a stabilizer may be considered as a simple form of a gas-processing plant. 

In a trayed absorber the amine falls from one tray to the one below in the same manner as the liquid in a condensate stabilizer (Chapter 6, Figure 6-4). It flows across the tray and over a weir before flowing into the next downcomer. The gas bubbles up through the liquid and creates a froth that must be separated from the gas before it reaches the underside of the next tray. For preliminary design, a tray spacing of 24 in. and a minimum diameter capable of separating 150 to 200 micron droplets (using the equations developed in Volume 1 for gas capacity of a vertical separator) can be assumed. The size of packed towers must be obtained from manufacturer s published literature. 

The static dielectric constant has been measured with a conventional dipolemeter DM 01 (WTW) working at 2MHz with a vertical cylindrical condenser especially designed to allow a great temperature stability (better than 0.03 C) and correct determination in situ of the temperature of the solution using either a thermocoax calibrated to 0.05 C or a conventional mercury thermometer. The estimated accuracy is 0.5%. 

Flow instabilities are undesirable in boiling, condensing, and other two-phase flow processes for several reasons. Sustained flow oscillations may cause forced mechanical vibration of components or system control problems. Flow oscillations affect the local heat transfer characteristics and may induce boiling crisis (see Sec. 5.4.8). Flow stability becomes of particular importance in water-cooled and watermoderated nuclear reactors and steam generators. It can disturb control systems, or cause mechanical damage. Thus, the designer of such equipment must be able to predict the threshold of flow instability in order to design around it or compensate for it. 

Thiophene and thienothiophene units have been frequently used in thienoquinoid or condensed forms in the design of new molecular architecture (16). Incorporation of the thiophene or thienothiophene unit as a rc-bridge linker could stabilize the quinoidal structure in the reduced forms (Figures 13 and 14). These two-types of new dications (222+ and 232+) stabilize the presumed two-electron reduction state by contribution of the thienoquinoid substructures (22 and 23) instead of the quinoidal form in the dication 212+ (77). 

This part includes a discussion of the main experimental methods that have been used to study the energetics of chemical reactions and the thermodynamic stability of compounds in the condensed phase (solid, liquid, and solution). The only exception is the reference to flame combustion calorimetry in section 7.3. Although this method was designed to measure the enthalpies of combustion of substances in the gaseous phase, it has very strong affinities with the other combustion calorimetric methods presented in the same chapter. 

There are three principles by which a flame process may be designed. A flame may form a desirable product by reacting to a favorable equilibrium state. The stabilization of an intermediate species may be achieved by quenching. Finally, the condensation of solids from flame products may be controlled to give desirable physical properties to the solids. 

---