Technical & Practical
Mechanical Carbon In Chemical Processing Equipment
Frequently, in chemical processing equipment it is possible to place the shaft support bearings in the chemical that is being processed. In some cases, this precludes the use of oil- or grease-lubricated bearings because the operating conditions are not conducive…
Fluid Flow
Laminar Pipe Flow For steady flow in a pipe (whether laminar or turbulent), a momentum balance on the fluid gives the shear stress at any distance from the pipe centerline. In Equation (1), Φ = P + ρ gz. The…
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…
Engineering Practice: Estimating Thermal Conductivity of Hydrocarbons
The thermal conductivity of hydrocarbons is an essential parameter that needs to be known when designing heat transfer equipment. Presented here is a simple-to-use correlation that was developed for predicting thermal conductivities of liquid paraffin hydrocarbons, petroleum fractions and atmospheric…
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…