Showing posts with label power generation. Show all posts
Showing posts with label power generation. Show all posts

Tuesday, July 19, 2016

Practical Issues of Combustion Oxygen Measurement Specifically Related to NOx Emissions

NOx emissions
Power plants and NOx emissions.
Power plants concerned with lowering NOx emissions are making tremendous changes to accommodate EPA regulatory requirements. A substantial number of these changes include the expansion and upgrade of the plant combustion oxygen measurement equipment. There is a striking relationship between the number of NOx reductions projects and the sales quantity of insitu oxygen detectors. The reason is that power plant betterment groups, operators, boiler manufacturers and engineering firms understand the direct relationship between NOx and excess air in the combustion process.

An area of daily practical importance to boiler operators and I&C teams are the common problems with insitu oxygen measurements. This paper focuses on the practical issues of combustion oxygen measurement as they relate to specifically to fuel usage and NOx emissions.

Read the entire white paper, courtesy of Yokogawa Corporation of America below:

Friday, March 11, 2016

Efficiently Detect Condensate in HRSG Drain Lines

waveinjector
Flexim WaveInjector sensor modified for HRSG Drains
The development of condensate in super heater and re-heater drains leads to trouble in combined cycle and cogeneration plants with heat recovery steam generators (HRSGs). The need to reliably detect and measure condensate in these drain lines is just beginning to emerge.

The Problem 

Heat recovery steam generators were never designed for cyclic service. The move toward renewable energy resources (such as wind and photovoltaic), in tandem with the ability of the combined cycle plant to start-up and stop quickly, is expanding the role of the combined cycle plant as a backup source of power. With frequent starts/stops condensate management becomes a problem. Draining this condensate is critcally important for the safe and reliable operation of the boiler. While the problem of condensate drainage has been around for years, the problem is far greater now with the more frequent start/stop cycle rates. The importance of finding a good solution for detecting condensate in the HRSG drain lines is growing.

Boiler manufacturers address this situation through the use of condensate pots, levels instruments, site glasses, and valves. None of these technologies provide a satisfactory combination of reliability, economy, and efficiency. Knowing when steam converts to water is difficult with this approach. Plus, over cautious systems sometimes release steam instead of condensate, wasting energy. A more reliable and consistent way to sense the presence of water in drain lines had to be found.

The Solution

By designing specialized mounting and tooling, modifying their sensing diagnostics, putting in hundreds of hours of field testing, and investing hundreds of hours improving their firmware for water detection, the manufacturer Flexim developed an ultrasonic flow meter that elegantly and reliably solves the HRSG drain line problem.

These clamp-on sensors work by measuring the transit-time difference of an ultrasonic signal, at varying flow velocities, through the process media. Ultrasonic, clamp-on flow meters have no moving parts, are not affected by density, and are mounted non-invasively directly to the pipe.

The most challenging aspects of this application are the high temperature sensor exposure and the thick-walled pipes with small diameters commonly used for drains.  To handle the high temperatures, specialized mounting and tooling were developed for the sensor allowing for pipe temperatures up to 750 deg. F. To overcome the small diameter / think pipe issue, Flexim engineers reconfigured the sensor’s firmware to change from measuring flow rate, and instead measure noise (decibels) as a innovative way to distinguish steam from water.

Flexim’s unique ability to measure the presence of liquid in condensate drain pipes is a revolutionary development. This valuable solution helps customers run longer and safer, minimizing downtime.

For more information, contact:

Flow-Tech
10940 Beaver Dam Rd
Hunt Valley, MD 21030
Ph: 410-666-3200

Central VA Office

10993 Richardson Rd#13
Ashland, VA 23005
Ph: 804-752-3450

Friday, December 4, 2015

Interesting Facts About Differential Pressure Cone Flow Meters

industrial differential pressure flow measurement device
Differential Pressure Cone Flow Meter
Courtesy McCrometer, Inc.
Requirements for measurement of flow exist throughout the industrial process control field. The applications are varied and vast. As a result, there are a number of technologies available for flow measurement and an even larger array of manufacturers providing devices and instrumentation that can be used to measure fluid flow.

Selecting the measurement technology that will provide appropriate performance for a process measurement application is an initial challenge for every process design. In order to accomplish this task, it follows that a well rounded understanding of the potentially positive or negative attributes for each methodology is necessary.

Differential pressure is one method of indirectly measuring fluid flow. It measures the change in pressure created as media flows past an obstruction in the fluid path, which, when combined with other information and calculation can be used to derive a measurement of mass flow. Like all measurement methods, there are applications where this one excels over others and some where it may not be as advantageous as alternate methods.

One manufacturer of differential pressure flow measurement devices is McCrometer. The company has been manufacturing DP flow measurement devices for over thirty years and has over 75,000 installations worldwide. In the company's own words, their flagship V-Cone product...
is an advanced differential pressure instrument, which is ideal for use with liquid, steam or gas media in rugged conditions where accuracy, low maintenance and cost are important.
Cutaway view of industrial cone flow meter
Cone Meter - Cutaway view
Courtesy McCrometer, Inc.
I have included below an interesting piece that provides, in brief form, some facts that will add to your knowledge of cone meters. Read the piece below. Contact a product specialist for any additional information you may need, or to discuss how this technology can make a positive impact on your industrial process measurement operations.