Archives :: Facts At Your Fingertips
March 1, 2012
To optimize process control and overall plant performance, magnetic flowmeters (mag meters) are the most widely used devices in many industrial flow-measurement applications. Mag meters are used to measure the flow of water and other conductive liquids by applying a magnetic field to the flowing liquid. Following Faraday’s law of electromagnetic induction, conductive liquid flowing through the...
February 1, 2012
Acidity is a critical parameter in the chemical process industries, and accurate measurements of pH can be important indicators for process quality control. A refreshed understanding of pH measurement can help to overcome process-specific challenges to measurement and to select the pH measurement devices that best meet the needs of the process. Further, a review of the temperature dependence of pH...
January 1, 2012
Pressure relief valves and rupture disks are critical safety devices for protecting personnel and processing equipment from overpressurization situations. Presented here are several engineering practices that can help to identify and address common problems with the pressure relief systems of chemical process industries (CPI) facilities. Common causes of overpressurization Overpressure situations can have...
December 1, 2011
Protecting process systems from overpressurization is a critical task in the chemical process industries (CPI), and rupture disks and safety relief valves are routinely used for this purpose. In certain situations, using rupture disks in combination with safety relief valves offers advantages that can increase safety and lower costs. The advantages include a significant lengthening of the service life of...
November 1, 2011
Effective level measurement helps ensure smooth, continuous processes by maintaining material inventory at economic quantities, and maximizes plant output by preventing spillage, system clogging and process upsets. In chemical process industries (CPI) applications, level measurement of liquids, powders and slurries are often complicated by the presence of steam, dust, foam, turbulence, caking or...
October 1, 2011
A well-operated steam generator can save money. In a steam-driven turbine system, water is heated in the steam generator to produce high-temperature, high-pressure steam. Steam is then expanded in a turbine to produce electricity from a generator. Turbine steam is condensed back into water in the condenser. A pump then returns the water to the steam generator. Engine thermodynamics Theoretically, the most...
September 1, 2011
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 as moist-heat (steam), radiation, ethylene oxide treatment and newer technologies. Each approach has advantages and...
August 1, 2011
A well designed and operated heat-transfer-fluid system is a key feature of a safe, reliable and cost-effective heating design. However, problems can arise if the heat-transfer fluid becomes heavily degraded or the system is allowed to accumulate solids and other process contaminants. These problems include the following: • Reduced heat-transfer rates • Diminished fuel efficiency • Flow...
July 1, 2011
Gas-liquid reactors in the chemical process industries (CPI) have increasingly been designed to handle larger manufacturing scales. Since gas-liquid reactors can represent substantial capital and operating costs for the user, optimizing mixing and maximizing productivity are critical. The need for efficiency at larger scales places more importance on understanding the physical phenomena of mixing and more...
June 1, 2011
Reciprocating pumps are often used in the chemical process industries (CPI) because of their ability to generate high pressures at low velocities. A subcategory of positive-displacement pumps, reciprocating pumps act through the recipricating motion of a piston, plunger or diaphragm. Such pumps work by way of a connecting-rod-and-crank mechanism with a piston. By nature, reciprocating pumps generate...
May 1, 2011
Pressure measurement in the chemical process industries (CPI) is crucial to many unit operations, and selecting the most effective pressure sensors for a given situation can be complicated by a range of factors. An initial key to selection is establishing an accurate understanding of exactly what is meant when the term “pressure” is used, since there are different types. Other critical...
April 1, 2011
Storing solid materials in hoppers, bins and silos is ubiquitous in the chemical process industries (CPI), as are challenges associated with dispensing them. In many cases, using vessels with steep cones and smooth walls is enough to provide reliable flow. However, it is not always feasible to design and install hoppers with the optimal geometry, and many solids have difficult or variable flow properties...
March 1, 2011
Contact-based temperature sensors, such as thermocouples and resistance temperature detectors (RTDs), have demonstrated accurate and cost-effective operation throughout the chemical process industries (CPI). However, there are many applications and settings where they are simply not practical. In those cases, engineers can turn to a host of non-contact temperature measurement devices, many of which are...
February 1, 2011
The precise monitoring and control of valve position is essential for efficient automation of both discrete and continuous processes. Measurement of valve position provides the data required for the use of advanced control strategies and predictive maintenance algorithms. More effective monitoring of valve position has been an area in which considerable progress has been made in improving the performance...
January 1, 2011
In recent years, a number of factors have further emphasized the importance of solvent selection in the chemical process industries (CPI). These include the increasing regulatory scrutiny leveled on industrial solvents, and an effort by CPI companies to reduce the environmental, health and safety (EHS) impact of their solvent use. In addition, specialized, high-performance solvents are available for some...
December 1, 2010
Most of the more than $100 billion in capital spending and $1.2 trillion in prodution costs spent annually by the chemical process industries (CPI) is committed by decisions made in the early phases of process development and plant design. A more disciplined approach to decision-making that fosters early attention to costs and more thorough consideration of available options has the potential to lower...
November 1, 2010
Measurement of fluids’ viscosity in the chemical process industries (CPI) can represent a useful “product dimension” for manufacturers. Understanding a material’s flow characteristics is valuable in predicting several parameters relevant to many CPI processes, including pumpability, pourability, performance in a dipping or coating operation, ease of handling or processing. The...
October 1, 2010
Crystallization is a key purification technique for various sectors of the chemical process industries (CPI). Several approaches for industrial crystallization have evolved over time and highly specialized crystallizer designs have been developed, especially in long-established industries. Solution crystallization is an important unit operation because the process can generate high-purity products from...
September 1, 2010
The deposition and accumulation of suspended and dissolved particles on membrane surfaces leads to performance loss. Fouling can dramatically reduce the efficiency and economic benefits of a membrane process. The type of fouling and how strongly it appears depends on several parameters, including the following: • Nature of solutes and solvents • Membrane process • Pore-size distribution...
August 1, 2010
OVERVIEW Indirect heating of processes by organic thermal-liquid fluids offers highly reliable operation, and the heat transfer systems are generally treated as low-maintenance utilities. Occasionally, the heat transfer fluid can become contaminated, resulting in the formation of sludge particles, or other sources of dirt can infiltrate the system. This contamination can cause operational problems. The...
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