The mechanical design and material science of pH-sensor technology have evolved dramatically over the last century. Current-day uses include a wide range of applications from high-purity pharmaceutical processing to wastewater treatment. Some of these applications pose high challenges to pH measurement, including high-temperature and otherwise harsh measuring environments, stability (particularly in pharmaceutical processes), low conductivity measurement and more-stringent pH control in processes. This article outlines the basics of pH measurement and control, with focus on some of these applications, and explores recent advances — such as the development of embedded memory chips and transmitters with smarter diagnostics and wireless communication — that have been developed to offer predictive maintenance, portability and greater stability.... http://www.che.com/technical_and_practical/pH-Measurement-And-Control_5894.html
Conventional trial-and-error vibration troubleshooting methods often fail to achieve the longterm, trouble-free pump operation sought, yet they can be time-consuming and increasingly costly to apply. Advanced tools are sometimes required for more subtle vibration problems that can still have a large impact.... http://www.che.com/technical_and_practical/Fine-tuning-Pump-Vibration-Diagnostics_5899.html
Acoustic coupling in industrial furnaces is an issue that appears to have become more prevalent as designs increase the volumetric heat density of furnaces, and burner technology is required to meet more-stringent emission requirements. The problems associated with acoustic coupling appear in the form of either large oscillations in the heater pressure or tonal and high-level emitted noise. Although the burner is often blamed for these occurrences, the coupling depends on both heater acoustic characteristics and burner dynamic characteristics. The acoustic coupling is a form of burner-heater interaction. This article shows that acoustic coupling in industrial heaters can be mitigated by enhancing the natural damping of the heater.
An experimental study on how one can enhance heater damping is presented. The approach depends on restricting the flow of fluegases while they exit a smaller side stack using an inducing device to enhance natural damping and hence mitigate acoustic coupling in heaters. The use of this technique is proven to be independent of burner type, in other words, burner combustion dynamics. So, details of the burner combustion dynamics do not have to be known for configuring and designing the device. The approach sheds some light on the conditions under which the tested burner engages in acoustic coupling.
Relief systems are the last line of defense for chemical process facilities. Verifying their capability to safeguard equipment integrity becomes important as process plants age, increase their capacities to adjust to new market requirements, undergo revamps or face new environmental regulations.... http://www.che.com/technical_and_practical/Aging-Relief-Systems-Are-they-Working-Properly_5808.html
Containing fugitive emissions of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) is a challenge to the chemical process industries (CPI). It has been estimated that these industries account for half of all fugitive emissions, and 60% of these emissions are the result of valve stem leaks. In addition to environmental benefits, effectively containing these emissions can yield significant operational and economic benefits and avoid punitive penalties for non-compliance with regulatory standards. If cap-and-trade or carbon-tax programs become law, then reducing emissions below mandated levels could yield carbon credits or reduced tax liabilities. Overall, emission reduction improves operating efficiency and creates a safer, more productive workplace.
This article describes how to effectively seal valve stems, including leak detection and repair (LDAR); various types of sealing solutions, their advantages and limitations; performance standards and testing; and proper installation.
Incorporating fire safety into plant design takes on two fundamental goals: to prevent the occurrence of fire and to protect the initially uninvolved piping and equipment long enough for operations personnel to perform their duties and for emergency responders to get the fire under control. While it is impractical to completely eliminate the potential risk of an accidental fire in a complex process-plant facility that is expected to handle and process hazardous chemicals, it is reasonable to assume that certain aspects of design can be incorporated to reduce that risk.... http://www.che.com/technical_and_practical/Piping-Design-for-Hazardous-Fluid-Service_5721.html
This self-priming pump is available for water and wastewater processing, This discharge pump ensures continuous flow of highly viscous fluids, These surface pumps boast low maintenance and high reliability, and more....... http://www.che.com/technical_and_practical/Focus-on-Pumps_5633.html
Wireless communications have great potential in the chemical process industries (CPI) because they do away with complex and costly cable installations and enable completely new applications. And while a recent wave of successful demonstrations has begun to emerge in the CPI (for more, see CE, Nov. 2009, p. 17–23), a number of hurdles stand in the way of a completely wireless Utopia. In most cases, the totally reliable, uncompromised availability of a production plant remains a paramount objective, and it will therefore likely take some more time before radio transmissions of critical signals in control loops take root.... http://www.che.com/technical_and_practical/Wireless-Communication-in-Hazardous-Areas_5639.html
A virtually endless number of process options are available for agglomerating powders in the chemical process industries (CPI). These processes can be divided into two main categories: agitation and compression. Agglomeration by agitation includes granulation processes, such as fluidized-bed, disc, drum and mixer granulators. Agglomeration by compression includes compaction processes, such as tabletting, extrusion, roll presses and pellet mills. Process choice is affected by certain feed attributes as well as a host of ancillary decisions. This article focuses on equipment selection criteria for granulation and compaction processes. The mechanisms of agglomeration were reviewed in an earlier article [ 1 ],... http://www.che.com/technical_and_practical/Agglomeration-Technology-Equipment-Selection_5641.html
Non-chemical methods for conditioning water for use in cooling towers and boilers have been investigated, marketed and installed for over 100 years. In light of the recent incentives to “go green,” these methods offer engineers, operators and owners the option of replacing corrosive, toxic chemicals with physical or mechanical processes that claim to produce the same or superior results to those obtained by traditional chemical treatment methods — often without many of the attendant environmental, health and safety concerns.The array of non-chemical water treatment equipment is impressive. And the assertions for the benefits derived from using these devices are equally impressive.... http://www.che.com/technical_and_practical/Non-Chemical-Water-Treatment_5565.html
The use of appropriate hazardous-area lighting in the chemical process industries (CPI) is a key factor when it comes to improving overall plant safety and worker productivity, and supporting the best maintenance practices. The potentially hazardous conditions associated with many industrial settings place high demands on the lighting fixtures, and it is essential that pathways, walkways and stairways in multi-level platforms or facilities be properly illuminated.
This article discusses the importance of using the most effective lighting practices in hazardous environments, and presents a conceptually new lighting approach — dubbed safety-centered lighting — that seeks to help facility operators choose and install the best hazardous-area lighting throughout the facility by combining knowledge of human physiology with the latest advances in lighting technologies, area-illumination techniques and installation practices.
As heat exchangers age, their tube thickness decreases because of erosion, corrosion or a combination of both. Installing thin sleeves in tubes in which the tube walls have become so thin that failure is imminent is a maintenance technique useful for extending heat exchanger life.
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