Tuesday, March 21, 2017

Industrial Temperature Control Basics

Process Controllers
Process Controllers used with thermocouples or RTDs
for temperature control (courtesy of Yokogawa)
The regulation of temperature is a common operation throughout many facets of modern life. Environmental control in commercial, industrial, and institutional buildings, even residential spaces, uses the regulation of temperature as the primary measure of successful operation. There are also countless applications for the control of temperature found throughout manufacturing, processing, and research. Everywhere that temperature needs to be regulated, a device or method is needed that will control the delivery of a heating or cooling means.

For industrial process applications, the temperature control function is found in two basic forms. It can reside as an operational feature within a programmable logic controller or other centralized process control device or system. Another form is a standalone process temperature controller, with self-contained input, output, processing, and user interface. Depending upon the needs of the application, one may have an advantage over the other. The evolution of both forms, integrated and standalone, has resulted in each offering consistently greater levels of functionality.

There are two basic means of temperature control, regardless of the actual device used. Open loop control delivers a predetermined amount of output action without regard to the process condition. Its simplicity makes open loop control economical. Best applications for this type of control action are processes that are well understood and that can tolerate a potentially wide variation in temperature. A change in the process condition will not be detected, or responded to, by open loop control. The second temperature control method, and the one most employed for industrial process control, is closed loop.

Closed loop control relies on an input that represents the process condition, an algorithm or internal mechanical means to produce an output action related to the process condition, and some type of output device that delivers the output action. Closed loop controllers require less process knowledge on the part of the operator than open loop to regulate temperature. The controllers rely on the internal processing and comparison of input (process temperature) to a setpoint value. The difference between the two is the deviation or error.  Generally, a greater error will produce a greater change in the output of the controller, delivering more heating or cooling to the process and driving the process temperature toward the setpoint.

The current product offering for standalone closed loop temperature controllers ranges from very simple on/off regulators to highly developed products with multiple inputs and outputs, as well as many auxiliary functions and communications. The range of product features almost assures a unit is available for every application. Evaluating the staggering range of products available and producing a good match between process requirements and product capabilities can be facilitated by reaching out to a process control products specialist. Combine your own process knowledge and experience with their product application expertise to develop effective solution options.

Wednesday, March 15, 2017

Combustion and Fired Heater E-Book

[All quoted passages in this article are taken from the Yokogawa e-book]

Yokogawa, globally recognized leader in a number of process control fields, has authored an e-book which provides useful insight into how operators of combustion based equipment and systems can improve efficiency and enhance safety by employing modern technology.

The Yokogawa e-book Combustion & Fired Heater Optimization offers "an analytical approach to improving safe & efficient operations" related to the use of combustion & fired heaters in the process industries. Through presenting an overview of combustion sources, such as furnaces and fired heaters, the book states that while "fired heaters pose a series of problems from safety risks to poor energy efficiency," those problems "represent an opportunity for improved safety, control, energy efficiency and environmental compliance." Fired heaters "account for 37% of the U.S. manufacturing energy end use." Tunable Diode Laser Spectrometer (TDLS) technology helps mitigate safety concerns by "measuring average gas concentrations across the high temperature radiant sections."

The book states that the four main concerns applicable to fired heaters are asset sustainability, inefficient operations, the operator skillset, and safety and compliance. Outdated diagnostics and controls have placed unnecessary stress on operator response, making sustainability of fired heaters difficult. The emissions of fired heaters are generally higher than designed, and can be coupled with control schemes for firing rates little changed over the past 40 years. Operators, generally, lack a clear understanding of design, and even engineering principles of heat transfer are not typically included in education related to fired heaters. Confounding the situation further, "many natural draft heaters do not meet this [safety regulation] guideline with existing instrumentation and control systems." These complications combine to form a noticeable problem Yokogawa's technology hopes to address. The company notes how the fired heater relies on natural draft instead of forced air, meaning the heaters "typically lack the degree of automation applied to other process units in the plant." Offering a full detail of both the control state of most fired heaters and their systems defines the process situation currently considered common in the field, while emphasizing high excess air as providing a "false sense of safety."

The proposed TDLS system allows for the measurement of "both the upper and lower conditions in a fired heater" by "simultaneously controlling the fuel and air supply based on fast sample intervals." Safer burner monitoring and heater efficiency results from the TDLS measurements of CO, CH4, and O2. The optimization of air flow control reduces "O2 concentration … from 6% to 2%" and increases the furnace's thermal efficiency. Combustion control is achieved by managing fuel flow and the arch draft. The TDLS integrated system works in tandem with already established logic solver systems in the plant. The TDLS technology works as a non-contacting measurement with "full diagnostic capability" and offers "distinct advantages over single point in situ analyzers" via reduction of false readings. Specific gas measurements, fast response time, optical measurement technology, and "high and variable light obstruction" are featured components of the TDLS system highlighted to show the technology's durability and flexibility. The longevity and reliability of the system is showcased by how the TDLS combustion management system has been operational in a major refinery since 2010. The percentage of excess O2 in sample fired heaters has decreased by 1% to 1.5%. Measurements by the TDLS system have been verified by other gas analyzers. The furnace conditions in the plant are more efficiently monitored and controlled. As a result, the furnace in the functional environment is "now near its optimum operating point, using minimum excess air."
Yokogawa presents a process-related problem, then details the key points of the problem while unpacking the causes. The e-book introduces Yokogawa's technology, explains the mechanics, and demonstrates how TDLS acts as a solution to the problem, supported by a tangible example. The book offers great insight for both the operational principles of fired heaters and a new technology designed to maximize efficiency in the control process.

The e-book can be downloaded here.  More detail is available from product application specialists, with whom you should share your combustion and fired heater related challenges. Combining your own facilities and process knowledge and experience with their product application expertise will lead to effective solutions.

Tuesday, February 28, 2017

Non-invasive, Ultrasonic Flowmeters Are Clear Winners in Wastewater Pumping Stations

non-invasive flowmeters on wastewater pumping stations
Non-invasive flowmeters installed on
wastewater pumping line.
Pumping stations are an integral part of each wastewater network. Flow measurement at such stations is critical as the quantities which are fed to the treatment plant have to be monitored.

Conventionally, magnetic inductive flowmeters are used for such measurement tasks. However, due the medium, which is heavily charged with solid matter, these instruments are subject to wear, leading to incorrect readings and subsequent failure.

Non-invasive ultrasonic flow meters prove to be the better measuring solution. Since these meters measure from outside the pipe wall, there is no wear and tear on the meter making them virtually maintenance-free. Furthermore, there is no need to open the pipe for installation, which would result in at least a partial interruption of operation. There isn't a need for multiple workers or heavy equipment for installation. The entire measuring system, consisting of ultrasonic transducers and a measuring transmitter, is easily carried to the measuring location and installed by a single person. There is no disconnection of pipes or flanged joints, unlike when installing a magmeter. Finally, there is no need for block valves to hold back flow during installation, repair, or replacement.

Advantages:
  • Reliable and accurate non-invasive wastewater flow measurement without any wear and tear or measurement drift
  • Extremely easy to set up a measuring point without any impairment of the plant’s normal operation
  • ATEX-certified transducers with protection degree IP68 for use in hazardous areas as well as in flooded chambers
For more information on non-invasive ultrasonic flow measurement, contact Flow-Tech in Maryland at 410-666-3200, in Virginia at 804-752-3450, or online at http://www.flowtechonline.com.

Monday, February 27, 2017

A New Twist on Old Magnetic Flow Meter Technology

FPI Mag Meter
FPI Mag Meter
The McCrometer FPI Mag employs a ground breaking configuration. Unlike full-bore mags, the FPI Mag is placed in the middle of the flow stream where an array of coils and electrodes measure at numerous points spanning the diameter of the pipe.

The FPI Mag's accuracy rivals that of conventional mag meters, so there's no compromise on performance. Save up to forty-five percent on installation and total cost of ownership. The FPI Mag is the only flow meter of its kind that eliminates the need for heavy equipment and excessive manpower necessary to support installation. Installing an FPI Mag is easy -  there's no need to shut down or drain the lines. The FPI Mag even fits in compact spaces with limited access points. Prep for conventional mag meter installation requires heavy equipment and draining lines. Conventional mag meter installation is costly complicated and time-consuming.

Benefits of using the McCrometer FPI Mag Meter:
  • Save up to 45% on installation and total cost of ownership
  • No downtime servicing or replacing the FPI Mag Meter
  • Over $5000 savings
  • 6 hours of labor saved

Friday, February 24, 2017

In Situ Microbial Fermentation Analysis and Mammalian Cell Culture Analysis - for R&D and Mass Production

Biopharmaceutical production processes, including microbial fermentation and mammalian cell culture vary greatly with organisms behaving differently and metabolizing at varying rates. With in-process measurements you can monitor the key parameters and optimize the fermentation or cell culture processes. Using a bioprocess analyzer allows for rapid analysis of many different properties with one quick measurement.

Both Fermentation and Cell Culture processes in a single, closed vessel can benefit greatly from in-process or in situ chemical analysis. Whether you are working with small laboratory scale reactors or large scale production equipment, Near Infrared (NIR) analysis can make your processes more efficient and optimized. NIR provides useful analysis for R&D, Scale-up, Process Development and full-scale production. Large-scale fermenters and bioreactors can hold as many as 250,000 gallons of raw material, which may be in process for hours or several weeks. An NIR analyzer can monitor both the start up media and emerging product on-line, despite the thick, soupy nature of the material.

Additionally you can get online measurements of Glucose, Glutamate, Acetate, Lactate, Ammonia,
Cell Density, Product Titer/Protein with NIR analyzers. These properties can be measured In-Situ or in the lab. If you have many fermentors/reaction vessels,  optical multiplexers will allow one analyzer to monitor up to 20 measurement points, sending all the valuable data to your process control system automatically.

In mass production the electrical power savings alone can provide payback for an NIR analyzer within a few months. Added product yield from improved process control also generates enormous payback, as well as reducing the occurrences of lost batches.

For more information visit Flow-Tech here or call 410-666-3200 in Maryland and 804-752-3450 in Virginia.

Thursday, February 9, 2017

Mass Flow Controller White-paper: A New Class of MFCs with Embedded Flow Diagnostics

Brooks G40
Mass Flow Controller
(courtesy of Brooks Instrument)
A white-paper by Brooks Instrument outlining recent trends in multi-sensor measurements within a mass flow controller are reviewed, with a focus on controller self-diagnostics.

For more information in Maryland or Virginia, visit www.flowtechonline.com or call 410-666-3200 (MD) or 804-752-3450 (VA).