Complex Unintended Consequences Obscure the Path Forward for Air Pollution
Control
A small Ohio town no longer exists thanks to the unintended consequences of air
pollution control. A nearby power plant spent hundreds of millions of dollars to
reduce NOx. The catalyst not only reduced the NOx it
converted SO2 to sulfuric acid. Within a few days, the acid
deposition did such great damage to the buildings in the town that the utility
agreed to buy the complete town and pay for relocations. In the ensuing
decade, catalyst suppliers have redesigned their product to eliminate this
problem.
New mercury regulations have such low emission limits that the instrument just
to measure gaseous mercury can cost hundreds of thousands of dollars. Prior to
issuing the regulation, EPA tested a number of stacks and found that all the
mercury existed in gaseous form. Therefore, the regulations only required
measurement of gaseous mercury. In response to the regulation
requirements, power plants, cement plants and waste-to-energy plants embraced a
two-step solution.
Step one was to convert the gaseous mercury to particulate mercury. Step
two was to remove the particulate mercury. The end result is that if step
one is very efficient and step two is not, there is lots of particulate mercury
being emitted. Another unintended consequence is that particulate mercury will
not travel far, whereas gaseous mercury can transverse the globe. Even though
this problem has been evident for a few years, there is still no proposed change
in the regulations.
The recent regulation of many pollutants combined with new technology which
makes it possible to remove all the pollutants in one device has greatly
increased the use of fabric filters. However, there has not been a recognition
of what McIlvaine describes as The importance of FIFO vs. LIFO in Dust
Cake creation.
Direct sorbent injection (DSI) and embedded catalyst dictate a new approach to
bag cleaning. In addition to
discrete particle capture, bag filters are being tasked with:
The importance of the method of bag cleaning can be illustrated by use of the
accounting approach to inventory. Two options are first in first out (FIFO) and
last in first out (LIFO). If the
price paid stays the same, the choice between the two accounting methods makes
no difference. But, if the cost of
recent inventory is greatly different than the past, then the accounting method
makes a big impact on profits.
The capture of discrete particles is the equivalent of price parity. Lets
say that when you pulse a bag you are always discharging the latest particles to
arrive and the remaining cake consists of the earliest. Since the ability of a
matrix of dust particles to act as a filtration medium does not change, it does
not matter which particles remain.
In fact, maintaining a somewhat permanent layer of cake protects the fabric from
wear. Also a more permanent cake provides higher dust capture.
It has been shown that on-line cleaning results in some re-deposit of
dust particles. But this is does
not impact discrete particle capture efficiency.
The new paradigm with DSI is a big price difference. The newly arrived lime
particle has the capability to absorb acid gases. The lime particle deposited
earlier is already converted to calcium sulfate and provides no additional
absorption capability. The semi-permanent cake layer is very undesirable for
acid gas capture. Mercury re-emission is also a risk for an activated carbon
cake which is semi-permanent. So it is very important to adopt FIFO and not
LIFO.
This leads to the obvious question as to which are the best cleaning methods to
achieve LIFO? The long running debate about surface filtration vs. depth
filtration needs to be reviewed in light of FIFO. Also, the pulsing method
itself needs to be reviewed. Do some methods result in more re-entrainment
of particles in the previous cake than do others?
Should more of the cake be removed with each pulsing?
It could be argued that the reaction takes place in the ductwork and not on the
bag. But the big difference in performance of bag filters vs.
precipitators with DSI proves that the cake absorption is substantial.
There may be lots of research on this subject but if so, McIlvaine would
appreciate feedback on it. If there is not, it is an area deserving lots
of attention.
Bag cleaning is also made more challenging by the increasing use of ceramic
filter elements. The advantage of these elements is the ability to remove dust
at 850°F. The older generation rigid ceramic has been replaced by ceramic
fiber media which can be pulsed. However, this media cannot necessarily be
pulsed with the identical system used for synthetic bags. An alumina refinery in
Australia was having cleaning problems with a ceramic filter.
Pentair Goyen analyzed the
situation and provided a more robust pulsing system. This solved the problem.
Ceramic, glass and even synthetic media are incorporating catalyst in the media
to reduce NOx or oxidize dioxins. Do these designs require a
different cleaning approach? The catalyst in the
Clear Edge design is not on the
surface. So, the dust cake will not affect performance except if it causes
maldistribution of the gas. If more
gas flows through one area than another, the reactivity of the system is
reduced.
A broader subject is the whole approach to cleaning. High pressure/low volume is
the most popular option. Does capture of these other pollutants open the door
for high volume /medium pressure or even for reverse air cleaning?
The potential for the one-stop shopping is great. Costs of pollution
control can be reduced for new installations. The small footprint makes a
big difference in the cost of upgrading existing plants to meet new air
pollution rules. It is, therefore, important to understand and then
maximize FIFO potential. McIlvaine
will be interviewing experts in the various niches to shed more light on this.
The results will be published in:
3ABC FGD and DeNOx Knowledge Systems
44I Power Plant Air Quality Decisions (Power
Plant Decisions Orchard)
Industrial Air Plants and Projects
For information on how to participate contact: Bob McIlvaine at 847 784 0012
ext. 112
rmcilvaine@mcilvainecompany.com.
Here are some Headlines from the Utility E-Alert April 29, 2016
UTILITY E-ALERT
#1270 April 29, 2016
Table of Contents
COAL US
COAL WORLD
The
41F Utility E-Alert
is issued weekly and covers the coal-fired projects, regulations and other
information important to the suppliers. It is $950/yr. but is included in the
$3020
42EI Utility Tracking System
which has data on every plant and project plus networking directories and many
other features.
New Route to Reach Prospects in Flow Control and Treatment Applications
The sales process for air, water, liquid and gas flow control and treatment
equipment can be likened to a trip using GPS with a series of zoom steps. It is
all possible because of digital technology. There was a time when the
national road atlas was the major tool for a trip across country. To find local
information you had to stop and ask questions.
This older system can be likened to the most common market approach to flow
control and treatment: a general market
report and a continuous flow of sales leads. The general market report is used
by senior management to set the course but is not detailed enough to help set
targets for individual sales people. The deficiencies in this approach are:
A general report may not provide the best forecasts. A top-down general forecast
is suspect. McIlvaine reports contain many thousands of individual forecasts
which aggregate to a general forecast. How do you reliably determine the
aggregate without determining the components? The suppliers of these general
reports claim to interview the experts and analyze all the financial
information. Any expert who does not have access to all the individual forecasts
is hampered in making a general forecast.
General reports typically rely on data provided by governments and associations.
These sources are good for determining the past but not the future. The most
useful data is very detailed. Use of government data which assess the mining
activity in each country is of questionable value compared to the use of
specific coal, iron ore, bauxite, potash, copper, gold and other mineral
production data. McIlvaine uses individual mineral forecasts. An approach which
tries to assess the mining opportunities generally in a region without a
specific breakout for each ore is flawed because mining activity varies widely
depending on the ore. Chile is a leading copper producer, whereas Canada is a
leading potash producer.
A report which is not continually updated is obsolete. The sudden drop in oil
prices resulted in an immediate need to evaluate and change many flow control
and treatment forecasts. The magnitude of the drop and the remaining political
uncertainties require continuous adjustment of forecasts. It is desirable for
management to set a flexible course for the year but also to make periodic
adjustments in advertising, promotion and manufacturing based on
revised forecasts.
The specific relevant market segments may not follow the general trends.
Flow control and treatment markets are frequently impacted by environmental or
other regulations. So the general industry trends do not reflect the markets.
The huge flue gas desulfurization (FGD) expenditures for pumps, valves,
scrubbers, monitors and belt filters are a function of regulations which impact
not only new plants but existing ones as well.
SALES LEADS: A large amount of money is spent on sales leads. They are
often too late if you are selling based on the best product rather than the
lowest cost. Since they are also provided simultaneously to competitors, the
unique value is diminished. Much of this expense can be avoided with the new
McIlvaine program: Detailed
Forecasting of Markets, Prospects and Projects
This program can be likened to the road trip with several zoom steps on the GPS.
The first step is to identify the markets which should be prioritized. McIlvaine
provides a number of standard reports on air, water, contamination and energy
markets:
MARKETS
The second step is to zoom in on the most relevant markets. Customized
segmentation provides forecasts which can be used at the individual salesman
level.
The next zoom step is to identify the large users and decision makers. The large
oil and gas, power, cement, food and mining companies buy the majority of the
flow control and treatment products. These companies should be a continuous
focus for the supplier.
The final zoom step is to focus on the projects being developed by the large
users, OEMs, and A/Es. The systems to provide this data are shown at:
Databases
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You can register for our free McIlvaine Newsletters at:
http://www.mcilvainecompany.com/brochures/Free_Newsletter_Registration_Form.htm.
Bob McIlvaine
President
847 784 0012 ext 112
rmcilvaine@mcilvainecompany.com