Technical & Practical
Cover Story Part 1: Heat Flux And Film Temperature In Fired, Thermal-Fluid Heaters
In a fired thermal fluid heater, a thermal fluid is heated by the metal surfaces of a fired heater or fluegas heat-recovery exchanger. Generally, the heat input rate is controlled to achieve some desired bulk-fluid temperature exiting the heater. However,…
Heat Transfer Fluids: Maintaining the System
Organic-based thermal fluids provide relatively trouble-free service for significant periods of time. However, there comes a time when any fluid (either aromatic- or aliphatic-based) needs to be replaced. Since aromatic-based fluids generally cost more and are complicated to dispose of,…
Bearing Housing Protector Seals for Gearboxes
Lubricant contamination in gearbox bearing housings can substantially reduce gear life. In critical applications, dual-face, magnetic bearing-protector seals will keep contamination out (Figure 1). Dual-face, magnetic bearing protectors are preferred in many difficult applications, such as wet cooling tower gearboxes,…
Engineering Practice: Functions for Easier Curve Fitting
Engineers often need to fit experimental data to an empirical relationship for extrapolation or modeling without resorting to a full mathematical treatment based on physical principles or theory. The most widely used platform in science for doing this is MS…
Facts at Your Fingertips: Biodiesel Production
Biodiesel can be produced from vegetable oils by three types of reactions: base catalyzed transesterification of the oil; direct acid-catalyzed transesterification of the oil; and conversion of the oil to its fatty acids, and then to biodiesel. Biodiesel is typically…
Cover Story: Process Modeling Moves Center-Stage
Process modeling has progressed from the "molecule accounting" of steady-state flowsheeting packages to become a central platform for capturing and deploying chemical process industries’ (CPI) intellectual property (IP). Systematic modeling has moved center stage to help companies differentiate themselves from…
Pressure-Relief System Design
Pressure relief systems are vital in the chemical process industries (CPI) for handling a wide variety of situations. They are used to prevent pressurization above a system’s design pressure; for venting during an unusual or emergency situation; and for…
Condition-Based Maintenance Management Enhances Reliability
Management is a process of managing risk; maintenance management is a process of managing risk for operational reliability. Since it is hard to manage what cannot be measured, effective maintenance management demands good data on machine health — a comprehensive…
Engineering Practice: Get More From Vertical Thermosiphon Reboilers
A very common heat exchanger in the chemical process industries (CPI) is the vertical thermosiphon reboiler (VTR; Figure 1). Due to size and fluid-flow restrictions, however, its heat transfer rate is often quite low. The subcooled region formed at the…
Facts at Your Fingertips: Heat Transfer System Design
Pumps Centrifugal pumps with cast or forged steel casings are typically appropriate for systems with large flowrates Positive displacement pumps frequently can handle smaller flowrates of less than 100 gal/min Sealless pumps (canned motor or magnetic drive) avoid the installation…