Heat transfer services

Several companies offer oils for heat-transfer service. Physical characteristics are summarized in Table 1. The oils discussed herein are widely used. Product brochures on the fluids are available from the manufacturers (3—12). 

The literature has many tabulations of typical coefficients for commercial heat transfer services. A number of these follow in Tables 2-8. 

The shell-and-tube exchanger is by far the most common type of heat exchanger used in production operations. It can be applied to liquid/liquid, liquid/vapor, or vapor/vapor heat transfer services. The TEMA standards dcTine the design requirements for virtually all ranges of temperature and pressure that would be encountered in an oil or gas production facility. 

A simplified schematic for a jacket heat transfer service is shown in Figure 11 [18]. Here, two separate heat transfer fluid headers are used, and the control valve is on the outlet stream to reduce the temperature shocks that might occur if a single... 

Conveyor-Befc Devices The metal-belt type (Fig. 11-55) is the only device in this classification of material-handling equipment that has had serious effort ejq)ended on it to adapt it to indirect heat-transfer service with divided solids. It features a lightweight construction of a large area with a thin metal wall. Indirect-cooling applications have been made with poor thermal performance, as could be expected with a static layer. Auxiliary plowlike mixing devices, which are considered an absolute necessity to secure any worthwhile results for this service, restrict applications. 

The disadvantage is that volumetric efficiency is usually much less than conventional trays or packed contactors. Applications are usually limited to cases when only a few transfer units or a single equilibrium stage is required. Since many of these applications tend to be in heat-transfer service, the following discussion will be in terms of thermal properties and thermal measures of performance. 

Vibratory-Conveyor Devices Figure 11-62 shows the various adaptations of vibratory material-handling equipment for indirect heat-transfer service on divided solids. The basic vibratory-equipment data are given in Sec. 21. These indirect heat-transfer adaptations feature simplicity, nonhazardous construction, nondegradation, nondusting, no wear, ready conveying-rate variation [1.5 to 4.5 m/min (5 to 15 ft/min)], and good heat-transfer coefficient—115 W/(m -°C)... 

The demethanizer is designed for complete separation of methane from ethylene and heavier components. The demethanizer is normally operated at approximately 7 atm. The demethanizer overhead consists of methane, plus relatively small amounts of hydrogen, carbon monoxide, and traces of ethylene. Brazed aluminum plate-fin exchangers are used for the multipass cryogenic heat-transfer services. Some ethylene plants employ high pressure demethanizers operated at approximately 35 atm. They are generally combined with either a front-end deethanizer or depropanizer. 

NACE Standard TM0286, Cooling Water Test Units Incorporating Heat Transfer Services, NACE International, Houston, TX. 

Calculating pressure drop is of considerable importance in atmospheric absorbers, heat transfer services, and vacuum distillations. Although pressure drop plots are available for most commercial types and sizes of random dumped tower packings, these data usually have been collected on air/water systems. While the air flow rate can be corrected for changes in gas density, no adequate method exists for handling the effect of liquid properties. 

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