Technical & Practical
Moving Air In Pneumatic Conveying Systems
Dilute-phase conveying systems generally use centrifugal fans and positive displacement blowers for supplying conveying air to the conveying system. However, for some conveying systems, compressed air from a central compressor station is also used. The two important criteria required for…
Reboiler Condensate Drums: Silencing Hydraulic Hammer
Condensate pots are commonly used on the condensing sides of some reboilers, such as those that are heated by steam or refrigerant vapor. These pots provide a liquid seal that prevents uncondensed vapor from blowing out of the reboiler into…
Reduce Costs with ‘Step-down’ Filtration
Among the challenges of effective solid-liquid filtration is the accumulation of solids on the filter surface, which creates an increasingly dense mass that process fluid must push through. In many applications in the chemical process industries (CPI), a step-down filtration…
Tank Vapors: Optimize Ejector Sizing for Better Control
Properly sized ejector stations can save capital costs and reduce downtime Steam-assisted, gravity-drainage (SAGD) operations employ large tanks that vent flammable and sometimes toxic gases. Safety and environmental concerns often require engineers to design vapor-recovery units (VRUs) to collect these…
Calculate Liquid Volumes in Tanks with Dished Heads
This article presents equations that allow the user to calculate liquid volume as a function of liquid depth, in both vertically and horizontally oriented tanks with dished heads. The equations accommodate all tank heads that can be described by two…
Sterilization Approaches
Maintaining high-purity conditions in the chemical process industries (CPI) depends in large part on the techniques used for sterilization. As a method to inactivate or eliminate potentially harmful microbes, sterilization can be achieved through a number of different approaches, such…
How long does it take to reach steady state?
How long does it take a six-tray, 4-ft dia. deisobutanizer to achieve steady state? That depends on your definition of “steady state”. Some control experts regard 95% of “ultimate value” as a good definition, but how useful is that definition?…
Preventing Self-Heating and Ignition in Drying Operations
Many solid materials can exhibit self-heating, which — if unchecked — can progress to a fire or even explosion. And even if the situation does not get that far, it is likely to affect the output of the process, in…
Todays Process Automation Worlds
Modern industrial-automation systems rely entirely on digital technology, that is, computers. And as is typical of digital products, suppliers love to add features — data collection, alarm management, and so on — that are very useful for process operations but…
Evaluating Capital Cost Estimation Programs
Capital cost assessment is an integral part of process design when building or expanding a chemical process plant. It is required to provide project analysis and evaluation, to select among alternative designs, to plan the appropriation of funds and to…