Thursday, April 21, 2016

Particulate Emissions Measurement

Particulate emissions measurement has long been a topic of nuanced discussion about how the manner of measuring the matter influences results.  The following discussion thread from the Source Evaluation Society's LinkedIn group covers some of those nuances.

Wednesday, April 20, 2016

Three Lessons in Innovation from Jeff Bezos

In a service industry driven by slow-moving Federal regulations, the first two lessons may be a bit less applicable, but #3 is universal.

The foundation of customer care is in the name: care about what your customers need and want. Anticipating their needs is essential to the framing that you build on top of that foundation.

Monday, March 28, 2016

Back to the Basics - Analyzing Oxides of Nitrogen (NOX)

Back to the Basics - Analyzing Oxides of Nitrogen (NOX)

Steve Hartman, Golden Specialty

The basic principle:
The chemiluminescent (a fancy way of saying light given off by a chemical reaction) NOX analyzer reacts NO with O3 (Ozone) to form NO2, O2 and light. The light comes from the decomposition of the O3 to O2. When air is passed through the ozonator, which is just a very high energy spark chamber, some of the oxygen atoms are excited by the high voltage to a higher energy state. Electrons in some of the oxygen atoms are moved into higher orbital shells and as such are able to then form the ozone molecule. But ozone is unstable and seeks to return to the stable O2 form. This is accomplished when it meets an NO molecule, the spare Oxygen is transferred forming NO2, and the extra energy that was stored in the O3 molecule is emitted as a photon of light as all those oxygen atoms go back down to their normal energy state.

There’s more to it:
The NOX converter comes into play because since the analyzer works by reacting NO with O3 to form NO2, if you already have NO2 in the sample you won’t see it. So the NOX converter, which operates at very high temperature, thermally breaks down the NO2 back into NO and O2 which can then be reacted with ozone and read.

The analyzer won’t work at all without an ozonator.  It will only read NO and not NOX without a working converter.

Still more about NOX converters:
There are two types of NOX converters, straight thermal and catalytic. The straight thermal is Stainless steel and operates around 600 - 650°C.  it breaks down the NO2 by temperature alone. The catalytic, usually made of a Chromium / Molybdenum steel, and called a Moly converter, operates much cooler, around 400°C. It relies on the catalyst to help break down the NO2, but since it is a catalyst, it gets used up over time.  When it has reached the end of the catalyst’s life it quits working. Moly converter service life is rated in ppm hours. If you had one with say a 10,000 ppm hour life, that would mean that it would operate for 10,000 hours with a 1 ppm NO2 concentration, but only 10 hours with a 1,000 ppm NO2 concentration. On a combustion turbine, NO2 is typically pretty low, except during startup when it can be 50% or more of the total NOX emissions. Many utilities have run into trouble trying to pass certification audits on turbine exhaust analyzers because their analyzers had Moly converters, which were quickly consumed.

So if a Moly converter gets used up and you don’t know whether it’s working, why would you use one in the first place? Good question, grasshopper.  The down side of a high-temperature of the Stainless converter is that it will break down ammonia causing it to be read as NOX, and giving a falsely high reading. This can be a problem on combustion sources using ammonia injection for reduction of NOX emissions.  In this case Moly is the best choice as it operates below the temperature to break down ammonia and the catalyst doesn’t react with ammonia. 

Monday, February 15, 2016

On Wednesday, Feb. 10 2016 EPA published a group of new Broadly Applicable Alternative Test Methods:

Source owners or operators should review the specific broadly applicable alternative method approval letter at before electing to employ it.

Alternative method decision letter/memo No.
As an alternative or modification to . . .
For . . .
You may . . .
Method 22-Visual Determination of Fugitive Emissions From Material Sources and Smoke Emissions From Flares
Sources subject to 40 CFR parts 60, 61, and 63
Use digital photographs for specific recordkeeping requirements.
Method 7—Determination of Nitrogen Oxide Emissions From Stationary Sources
Sources subject to 40 CFR part 60, subpart G, Standards of Performance for Nitric Acid Plants
Use Method 7E-Determination of Nitrogen Oxides Emissions from Stationary Sources (Instrumental Analyzer Procedure) in conjunction with the specific application instructions defined in 40 CFR 60.73a(b)(4).
Method 5-Determination of Particulate Matter Emissions From Stationary Sources or Method 5B—Determination of Nonsulfuric Acid Particulate Matter Emissions From Stationary Sources
Electric utility steam generating units meeting the criteria referenced in the Agency's approval letter and subject to40 CFR part 63, subpart UUUUU;40 CFR part 60, subpart D; and40 CFR part 60, subpart Da
Use Method 5I to conduct quarterly compliance testing and/or certification and ongoing QA testing of the installed PM CEMS.
Performance Specification 18-Performance Specifications and Test Procedures for Hydrogen Chloride Continuous Emission Monitoring Systems at Stationary Sources and Procedure 6
Stationary sources in which hydrogen chloride (HCl) is measured continuously to demonstrate compliance in 40 CFR part 63, subparts LLL, UUUUU, and DDDDD
Include measurement path during calibration drift testing according to the provisions specified in the Agency's approval letter dated September 25, 2015.
Requirements for performance tests——
Sources subject to 40 CFR part 60, subpart KKKK, Standards of Performance for Stationary Combustion Turbines
Conduct the initial and subsequent performance tests on turbines at ambient temperatures below 0 °F, provided that you operate the inlet air preheaters such that the turbine inlet air temperature is always maintained above 0 °F.

Monday, February 1, 2016

Accreditation in Stack Testing

To date, Golden Specialty is one of a small group of firms that has achieved all of the major stack testing accreditations:

In addition, our in-house analytical laboratory carries several rigorous accreditations:
Accreditation is a vital element of the firm's quality systems, and introduces the credibility of independent assessors from established third-party organizations.
Come visit us at EUEC 2016, Booth # 458.
Hitting the High (and Low) Points: are your testers traversing for moisture?

Ron McCulloch

Golden Specialty, Inc.

At times, it may seem as if regulatory observers of stack tests are excessively critical, but when they call out flaws in testing procedures, they tend to have good reasons.  One detail of test methods that is easy to overlook in the flurry of testing activity is the requirement to traverse while sampling for stack gas moisture (EPA Method 4).

With most manual testing, such as for particulate matter (Method 5) or volatile metals (Method 29), Method 4 is integral to the main test method.  As such, traversing the stack cross section is built-in, and therefore not a deliberate consideration with regard to the moisture sample.  However, when performing moisture measurements – usually to support flow rate measurements, it’s easy to let such details become afterthoughts.

While moisture stratification is unlikely in most testing scenarios, and even worst-case calculations based on zero moisture may demonstrate that a unit is in compliance with applicable limits, regulators still may reject an entire test program, simply on the basis that a tester did not meet method requirements by traversing the moisture sample.

While in most cases, the scientific validity of a test may remain intact using data from single-point moisture measurements, testers remain subject to the letter of the reference methods:
EPA Method 4 Section “Unless otherwise specified by the Administrator, a minimum of eight traverse points shall be used for circular stacks having diameters less than 0.61 m (24 in.), a minimum of nine points shall be used for rectangular stacks having equivalent diameters less than 0.61 m (24 in.), and a minimum of twelve traverse points shall be used in all other cases. The traverse points shall be located according to Method 1. The use of fewer points is subject to the approval of the Administrator. Select a suitable probe and probe length such that all traverse points can be sampled.”

Taking time to perform the traverse is a comparatively small effort.  Repeating the test is a large, expensive one.

Happy stack testing!