Chemical Engineering Practice

Team Up with a Consultant for Process Equipment Selection

August
2006
Career Catalyst
Gregory T. Benz
Engineers who specify, scale up or purchase process equipment typically have fewer internal or vendor resources available than in the past. This article explores the problem and offers a solution.

Selecting Agitator Seals for Bioprocessing Applications

January
2008
Fluids and Solids Handling
Gregory T. Benz, William Ho Liam Teng
Issues such as sterility, isolation and contamination must be considered when choosing seals for use in biotech and pharmaceutical processes. This overview describes common types of seals and offers guidance on selecting the appropriate seal for...

Correlate Data Effectively

February
2011
Computational Methods
Faruk Civan
Follow these nine simple rules to avoid common pitfalls and get better results.

Tune Control Loops for Minimum Variability

January
2002
Instrumentation
Lanny A. Robbins
The Robbins tuning rules can reduce the variability of control loop response to about 60% of that observed with Ziegler-Nichols tuning rules.

Guidelines for Crystallizer Selection and Operation

October
2004
Reactions and Separations
Wayne Genck
Continuous crystallizers serve a wide range of applications in the chemical process industries. Optimize system performance by heeding these practical design and operating principles, which apply to the forced circulation (FC), draft-tube-baffle (...

Improving the Reliability of Mechanical Seals

November
2005
Operations And Maintenance
Michael Huebner
With a better understanding of seals, their selection, material considerations, and operation requirements, users can greatly improve equipment reliability and reduce operating costs.

Streamlining the Validation Process

March
2007
Management
Robert Mackey, Tim Flanigan
Today, validation is no longer an afterthought for the design and construction of a new or renovated process or facility. It is, in fact, recognized as an integral part of the total project. Fully integrated services are now available to ensure a...

Rx for Pharma

March
2009
Critical Issues
Girish Malhotra, P.E.
Chemical engineers could hold the key that helps pharmaceutical companies — facing pressure to control rising drug prices and competition from generics — reduce their manufacturing costs.

Designing Dust Collectors

September
2011
Fluids and Solids Handling
Greg Mehos, P.E.
To assure reliable and safe operation of a dust collector, apply the basic principles of chute and hopper design — which are based on the dust's fundamental flow properties.

Choose Materials for High-Temperature Environments

February
2001
Materials
Peter  Elliott
High temperatures, stresses, and the presence of elements such as oxygen, sulfur, or the halogens can add up to trouble. Here is how to screen candidate alloys for such service.

Steam Trap Troubles?

February
2005
Heat Transfer
Trinath Sahoo
First, prevent problems by selecting the appropriate trap and installing it properly. If problems arise, follow these guidelines for diagnosing and correcting them.

Estimate the Capacity of Simple Batch Processes

August
2002
Reactions and Separations
James L. Manganaro
Finding the throughput of a multiple-unit, multiple-step operation, even when it is relatively uncomplicated, is not always an easy matter. Several equations and graphical aids are provided to help determine yearly capacity.

Avoid Sulfolane Regeneration Problems

July
2004
Reactions and Separations
Donald F. Schneider
The regeneration of sulfolane, a common extraction solvent, is difficult. With proper attention to design and operation, problems can be minimized.

Selecting Corrosion-Resistant Materials

December
2006
Materials
Francesco Picciotti, Marcello Picciotti
This article looks at some common corrosion-resistant alloys and gasket materials that are available for use in applications with high pressures and temperatures.

Evaluating Cooling Tower Upgrades

May
2008
Heat Transfer
Tom Dendy
When considering improvements to cooling towers, it's important to perform an economic analysis of the options.

Evaluating and Documenting Tower Performance

February
2010
Reactions and Separations
Daniel R. Summers
A good performance evaluation can lead to a significant improvement in column performance and establish a basis for future tower evaluations. <br>

Integrate Compressor Performance Maps into Process Simulation

June
2011
Computational Methods
Grant Stephenson
Transforming the performance maps to a reduced coordinate system that is independent of suction conditions and rotational speeds allows these curves to be accurately incorporated into a process simulator.

Find Mixing Success through Failures - Part 1

October
2008
Fluids and Solids Handling
David S. Dickey, Gary K. Patterson
Understanding when and why mixing fails in the laboratory is often the only way of avoiding a similar failure in a production-scale reactor.

Bridge the Gap with Semicontinuous Distillation

August
2001
Reactions and Separations
James R. Phimister ,  Warren D. Seider
This processing strategy combines the advantages of batch and continuous operation, providing flexibility and efficiency in a single design.

Evaluating the Economics of Desalination

December
2002
Heat Transfer
Hisham M. Ettouney, Hisham T. El-Dessouky, Peter J. Gowin, Ron S. Faibish
This article presents an in-depth analysis of thermal and membrane desalination economics and outlines a simple procedure for calculating the unit product cost for various desalination processes.

Building Models from Simulator Runs

January
2006
Computational Methods
Aad van Veldhoven, Magali de Macedo
The design-of-experiments approach has the advantage of providing the framework to build complex models with minimum use of time and effort.

Obtain the Best Physical Property Data

May
2009
Fluids and Solids Handling
Kevin G. Joback
Physical property values are essential for many chemical engineering tasks. This article reviews sources of physical property data, discusses the use of experimental methods to measure properties, and details several types of estimation techniques.

Nitrogen: A Security Blanket for the Chemical Industry

November
2011
Fluids and Solids Handling
Bill Carlson, Joe Dumoit, Paul Yanisko, Shiying Zheng
The benefits of nitrogen blanketing include improved process safety, better product quality, and longer equipment life. Here's how to achieve the desired safety or quality results while minimizing costs.

Innovations in Food Processing

March
2003
Fluids and Solids Handling
B. G. Swanson, G. V.  Barbosa-Cánovas, M. F. San Martín
Today's savvy consumers want processed foods to look freshly prepared, while still meeting all safety requirements. Conventional thermal treatments are inadequate to fulfill this demand. New nonthermal techniques, such as pulsed-electric fields, are...

Prevent Caking During Solids Handling

May
2005
Fluids and Solids Handling
Brian H. Pittenger, Gabriel I. Tardos , Herman Purutyan
Use these guidelines to avoid potential caking problems. The key steps are to select a material characterization method, identify the factors that can be feasibly controlled and conduct tests to confirm that process/handling changes yield the...

Integrate EHS for Better Process Design

February
2002
Process Development
Lisa Bendixen
Get a jump on process development by addressing environmental, health and safety (EHS) issues together early in the design and development cycle. The result will be a better process and lower costs.

Can We Believe the Simulation Results?

October
2002
Reactions and Separations
Henry Z. Kister
Be careful of these key issues that may generate differences between a distillation-tower simulation and its actual performance. Simulations do not always square with nuts-and-bolts reality.

Simulating Aqueous Processes

September
2003
Reactions and Separations
Joel B. Christian
Simulation that includes aqueous modeling can also account for full vapor/liquid/solid equilibria modeling, including redox chemistry.

Examining X-Ray Technology

March
2009
Fluids and Solids Handling
Ray Spurgeon
Use X-ray inspection to see whether your product is contaminant-free and packaged properly.

The Flange Factor in Gasket Selection

September
2011
Fluids and Solids Handling
Dave Burgess, John Crandall
Gaskets should be chosen based on service conditions, as well as the type of flanges to be sealed. These principles will help to guide the selection.

Run Clean with Dry Vacuum Pumps

October
2001
Fluids and Solids Handling
Jim  Ryans, Joe  Bays
The use of dry pumps is growing, replacing workhorse steam jets and liquid-ring pumps. Here is a comprehensive selection guide.

Track Condenser Performance

February
2003
Heat Transfer
Brad Buecker
An effective monitoring program can extend equipment life, improve operations, and yield substantial energy savings.

Pumping System Head Estimation

February
2005
Fluids and Solids Handling
James Anthony
These spreadsheets highlight losses, uncertainties and value of power used, helping you optimize pumping system designs and save on operating costs.

Avoid Problems in Process Water Systems

October
2007
Heat Transfer
Marilyn W. Blaschke, Roger D. Metzler
Prevent corrosion, emulsification and fouling by implementing these operational and chemical measures.

Computational Science: Enabling Technology Development

January
2011
On The Horizon
Anthony Cugini, Chris Guenther, Jinghai Li, Madhava Syamlal, Ning Yang, Wei Ge, Wei Wang
Computational science will play a key role in accelerating technology development and in the realization of virtual process engineering.

Optimize Heat Exchanger Cleaning Schedules

June
2001
Heat Transfer
Brendan R. O'Donnel, Bruce A. Barna, Chris D. Gosling
Get the most out of your heat exchanger by evaluating the trade-offs between a one-time expenditure and reduced operating expenses, increased income, and/or longer operating life span. Brendan R. O'Donnell - Bruce A. Barna - Chris D. Gosling -

Take the Guesswork Out of FRP Corrosion

December
2001
Fluids and Solids Handling
Gunnar Bergman
The lifetime of fiberglass-reinforced plastic equipment and piping often depend upon previous experience. Here's a way to predict and prolong service life.

Optimizing Crystallizer Scaleup

June
2003
Fluids and Solids Handling
Wayne Genck
Explore how mixing parameters impact the crystallization process and recommend ways to improve the likelihood of successful scaleup. The concepts of nucleation and growth, types of mixing, design considerations, agitator parameters and scaleup...

Dynamic Capacity Modeling of Product Development

July
2004
Information Technology
Brian E. Hartman, Jospeh S. Alford Jr., Prashant B. Kokitkar
Avoid large work queues by proactively anticipating the resource needs of your company using dynamic capacity models.

A Simple Approach to Vapor Pressure Prediction

January
2007
Reactions and Separations
Andrew J. DeDoes, Matthew D. Goetz, Michael J. Misovich
This method reproduces the vapor pressure predictions of the Soave-Redlich-Kwong and Peng-Robinson equation of state with a simple Antoine equation that uses constants derived from critical properties and the acentric factor.

Find Mixing Success Through Failures - Part 2

December
2008
Fluids and Solids Handling
David S. Dickey, Gary K. Patterson
Understanding when and why mixing fails in the laboratory is often the only way of avoiding a similar failure in a production-scale reactor. Here we examine mixing in stirred-tank reactors and provide guidance on scale-up.

Understand the Real World of Mixing

March
2010
Back To Basics
Thomas Post
Most chemical engineering curricula do not adequately address mixing as it is commonly practiced in the chemical process industries. This article attempts to fill in the gaps by explaining flow patterns, mixing techniques, and the turbulent,...

Don’t Let Baffle Tray Flood Baffle You

July
2011
Reactions and Separations
Henry Z. Kister, Matthew Olsson
Use this new correlation based on window liquid velocity to predict baffle tray capacity.

Applying Bus Technologies in Process Control

December
2002
Instrumentation
Ed Smigo
Fieldbus technologies have become increasingly popular in process control applications. This article highlights the practical applications and economics of various buses, so that an engineer can choose the best one for his or her process.

Matching Your Process Constraints Using Dynamic Simulation

December
2003
Information Technology
Iban Grau, Jose J. Macias-Hernandez, Miquel A. Alos
A rigorous dynamic process simulator can be used to evaluate alternative control strategies for an exothermic reacting process in order to improve its safety and product quality.

Designing Experiments for the Modern Micro Industries

February
2006
Computational Methods
Phillip H. Williams
Although the sparsity of effects principle is still good advice, we need to be careful of emphasizing it too much -- to the point that it becomes an assumed practice, rather than a useful rule of thumb.

Understand the Fundamentals of Centrifugal Pumps

October
2010
Back To Basics
J. Howard Kelly, P.E.
Efficient and reliable pumps can significantly improve a plant’s bottom line. This article reviews important concepts that a chemical engineer must understand and the factors that need to be considered when selecting radial-flow centrifugal pumps.

Understand Thermodynamics to Improve Process Simulations

December
2011
Computational Methods
David Hill, Fred C. Justice, P.E.
Selecting a thermodynamic model is an important step in process simulation — one that many engineers overlook. This overview of applied thermodynamics can help you choose the right model for your process.

Squeeze More Out of Complex Columns

July
2002
Reactions and Separations
Piyush Shah
These distillation setups can cut capital and operating costs by up to 30%, and increase separation efficiency. Here is a straightforward method for evaluation.

Understand Temperature Change in Process Stream Mixing

September
2006
Heat Transfer
Anil K. Mehrotra, Dharmendra Tiwary
The isobaric and adiabatic mixing of process streams can yield an outlet stream temperature that is either in between, higher than, or lower than the inlet stream temperatures. This article uses simulation to explore temperature-change scenarios in...

Use Spreadsheets to Estimate Modeling Parameters

February
2008
Computational Methods
Tomas B. Co
Dynamic process modeling based on non-uniformly sampled data and multiple sampling runs, even for nonlinear systems, can be performed using spreadsheet implementations of the weighted-least-squares (WLSQ) and Runge-Kutta WLSQ methods.

Validate Your Engineering Software!

July
2001
Instrumentation
Michael  Tanzio
You really can't guarantee that applications work correctly unless you take specific steps to validate the software.

Don't Get Burned Picking Dry-Type Flame Arresters

October
2002
Fluids and Solids Handling
Stanley G. Grossel
These commonly used devices rely on an internal medium to extinguish flame fronts and take the punch out of shock waves, protecting piping, equipment and personnel. Selecting such equipment involves considering the probable type of combustion,...
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