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A primer on coal-to-liquids

As an energy resource, global coal reserves represent 2,000 billion barrels of oil equivalent. In 2007, global oil reserves were about 1,300 billion barrels of oil. World wide, oil demand will grow 40 to 50% by 2030. But coal offers…

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Tray Column Design

Here, we present criteria needed for the intelligent, effective specification of trays for a distillation or stripping column. Among the key parameters and accessories during specification are column diameter, tray spacing, number of trays, number of passes, type of downcomers,…

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CSTRs: Bound for Maximum Conversion

Here, a design approach for continuous stirred-tank reactors is outlined for both reversible and irreversible second-order reactions Multiple CSTRs (continuous stirred-tank reactors) are advantageous in situations where the reaction is slow; two immiscible liquids are present and require higher agitation…

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…

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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,…

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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,…

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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,…

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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…

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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…

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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…