E1.1 Air Quality Control Technologies for Combustion Turbines – Combined Cycle & Simple Cycle Configurations
Chris Wedig, Senior AQCS Specialist, CB&I
This presentation provides an overview of air quality control (AQC) technologies that utilities and
industries will use to address regulations for combustion turbine (CT) plants, including combined cycle
and simple cycle configurations. It describes the design, construction, operation, and maintenance of
the AQC technologies for different combustion turbine power plants and fuels. It includes numerous
different types of technologies and impacts & process interaction of these AQC technologies on
the plant. The presentation presents the mass & energy balances for various AQC systems, with a
description and characteristics of CT range of fuels, in-duct burner fuels, ambient conditions, reagents,
stack flue gas & emissions, and waste byproducts produced. It describes various regulations that
apply to combustion turbine projects. The presentation addresses pre-combustion, combustion, post
combustion and other types of AQC technologies. It presents the impact of AQC system on BOP areas
(electricity, water, steam, air, waste disposal). For combined cycles, it addresses impacts of AQC system
on the HRSG. For simple cycle configuration, different types of potential retrofit AQC systems (including
impacts on power plant) are presented. The presentation includes impacts of AQC technologies
during the construction, commissioning, and testing phases of the project, and after start-up topics,
including reliability, load following (ramp-up and ramp-down), and other plant performance issues.
E1.2 Control Particle Size, Control Your Process
Jeff DeNigris, Sales Mgr, Malvern Instruments
Pulverized Coal power, still a viable source of electricity for many, begins and ends with efficiency
of SIZE. Particle size, first of the pulverized coal and then at the clean air end with SOx and NOx
mitigation, is generally unknown and uncontrolled. While the coal is pulverized in large quantities and
in a fairly stable process, there are many variable that directly affect the particle size of that coal, and
its performance. Whether it is in its combustion rate or conveying ability, PSD is the critical purpose to
that very expensive size reduction process. Using On-Line real-time Laser Diffraction, this process can
be monitored, 24/7, to determine the PSD and control it to produce the optimum size for the greatest
process efficiency. Likewise, but on the other end of the coal fired process, the control of air pollution
control methods, such as desulfurization, is driven by surface area reaction. This could be while using
a milled activated carbon or a Trona like product, both used for different results but much the same
process: Mill to fine particle size, inject and absorb unwanted chemicals in the air. Particle Size, again,
is critical to these additives performance, and it can be monitored and controlled, all in real time, with
the same type Laser Diffraction system.
E1.3 Advancements in Semi-Dry Scrubbers
Jeromy Jones, AQCS Manager, Burns & McDonnell
This paper will provide an update on Semi-Dry Scrubbers including enhancements that have been made
to Circulating Dry Scrubbers (CDS) and other uses for Spray Dryer Absorbers (SDA). The enhancements
will include a discussion on layout optimization and differences in recent OEM modifications. The SDA
update will depict how an SDA can be used upstream of an existing wet scrubber and particulate
control device to eliminate or reduce the need for a typical waste water treatment system. Several
utilities are evaluating this configuration as they investigate what is required for a zero liquid discharge
system.
E1.4 100% Availability – The Holy Grail of AQCS Design
Chris Tovee, Senior Engineer, Hatch; Dr. Michael Trovant
Designing air quality control systems (AQCS) for continuous availability is currently being mandated
throughout the world in many industries, and implementation for electric utilities will soon be critical.
This presentation examines some of the key design considerations associated with reliably attaining the
100% availability benchmark, including redundancy requirements, on-line maintenance capabilities,
flow re-distribution strategies, isolation requirements and other related issues. Integration of energy
recovery equipment resulting in improved energy efficiency is also described. A dedicated state-ofthe-
art 340,000 SCFM AQCS has been engineered for a large coke oven battery to achieve continuous
availability and compliance with Boiler Maximum Achievable Control Technology (MACT) standards.
The system is designed to ‘best available control technology’ standards by incorporating circulating
dry scrubbing technology, three heat recovery steam generators and one 82 MW steam turbine
generator for energy recovery.
E1.5 How to make pollution control profitable
Jerrold Radway, Chairman & Chief Technical Officer, ClearChem LLC; Shuman Moore
New R&D has spawned a very low capital cost Furnace Sorbent Injection technology (ClearChemFSI)
that captures sufficient acid gases to allow many power plants to meet emissions regulations. It does so
at a very modest stoichiometric level, without stressing particulate collection equipment while mitigating
ash deposits & facilitating lower system exit temperatures that boost unit efficiency & enhance the
economics of recovering water from flue gases. It can be used to economically upgrade existing
scrubber performance & to significantly lower the capital cost of new scrubbers or in combination with
back-end DSI. The presentation describes: 1) the positive results from full scale demos of the advanced
FSI technology, 2) the process changes that have already made the technology a commercially viable
pollution control tool, 3) ongoing R&D aimed at further enhancement of FSI performance.
E1.6 The Role of Microgrids in the Smart City
Terry Mohn, CEO, General MicroGrids, Inc
Increased integration of renewables and adoption of microgrid technologies pose both opportunities
and risks for utilities. Embracing these technologies can allow utilities to ensure a more efficient, resilient,
and sustainable power grid. This presentation will discuss the advances of microgrid technology and
business models within the Smart City. Explore the adoption of microgrids in the Smart City. Review
advances in technologies that foster increased benefits to the power grid. Discuss the evolving
business model of microgrids and how utilities can embrace microgrid adoption through evolving
business models.
E7.1 Development of novel SCR-DeNOx catalysts – reviewing the results of recent European research projects
Barna Heidel, Head of Department, Institute of Combustion & Power Plant Technology, University of
Stuttgart; Tobias Schwämmle & Günter Scheffknecht
One very promising method to reduce mercury (Hg) emissions of coal-fired power plants is the installation
of novel high-dust SCR-DeNOx catalysts, which leads not only to reduced NOx emissions, but also to
an increased oxidation of Hg. Combined with wet flue gas desulphurisation, Hg removal of up to 90%
can be achieved. By the use of optimized catalysts, removal rates of Hg can be increased without any
additional operating resources. Funded by the European Commission, the projects DENOPT & DEVCAT
are focussing on the improvement of commercial SCR-catalysts. Research is carried out to understand
the interaction of the relevant reactions at the catalysts as well as the catalyst’s behaviour related to
its chemical composition, leading to novel high-performance catalysts. Experimental investigations in
different facilities, from laboratory-scale via bench- & technical-scale up to full-scale power plants are
carried out within the framework of the projects. The proposed presentation will describe the effect
of different catalyst composition of newly developed high-performance catalysts on Hg oxidation.
Special focus is put on the influence of the parallel proceeding reactions of NOx-reduction & SO2/
SO3-conversion on mercury oxidation. Additionally, the tests have been performed at various flue gas
atmospheres. The results will be compared with measurements of standard commercial catalysts & the
discussion will also include reaction mechanisms as well as economic aspects.
E7.2 Increases in NOx Emissions in Coal-Fired SCR-Equipped Electric Generating Units
Tom McNevin, Research Scientist, NJDEP
The most effective control technology available for the reduction of oxides of nitrogen (NOx) from coalfired
boilers is Selective Catalytic Reduction (SCR). Emissions data for NOx from the USEPA’s Air Markets
Program Data tool (AMPD) were analyzed through the duration of the three multi-state NOx cap and
trade programs administered by EPA, from 1999 through the 2013 May – September ozone seasons.
In recent years, NOx emission rates of many SCR-equipped coal-fired EGUs have increased substantially
over their best observed rates (BOR). This coincided with a collapse in the cost of CAIR allowances,
which was accompanied by a 77% decline in delivered natural gas prices from their peak in June of
2008 to April 2012, which in turn coincided with a 490% increase in shale gas production during the
period. These years also witnessed a decline in national electric generation which after peaking in
2007 declined through 2012 at an annualized rate of – 0.7%. The confluence of collapsed allowance
costs, with reductions in both the cost of competitive gas-fired electrical generation and reduction
in electrical sales, has had a significant impact on the operations of many coal-fired, SCR-equipped
EGUs. Comparison of actual NOx emissions in the eastern US over the 2010 – 2013 ozone seasons to
what would have been emitted had units operated at their BORs indicated a release of over 189,000
tons of NOx in excess of what the technology installed in these units was capable of achieving.
Larry Czarnecki, Principle Process Engineer, Alstom Power; Paulo Oliveira
The technology of SCR systems has continually improved since the early designs developed in
the U.S. in the 1990s. In addition to better performance, such as higher NOx removal levels and
more robust operation, costs for SCR systems have decreased with improvements in catalyst
technology, reactor design, and ammonia supply components. Advanced IsoSwirl™ ammonia
distribution systems require less additional catalyst to compensate for poor ammonia to NOx
distributions. Redesigned reactor catalyst arrangements offer benefits towards more compact
reactor configurations. Innovative catalyst handling facilities offer the potential for rapid catalyst
loading or replacement cycles. Quick catalyst handling facilitates a catalyst management
plan which avoids the requirement and associated costs with spare layers in the catalyst reactor.
This presentation will discuss the features of these various SCR system improvements. An economic cost
analysis contrasting the savings between the improved SCR system and a conventional SCR system
designs will be presented.
E7.4 Hot SCR Systems for Large Frame SImple Cycle Gas Turbines
Robert McGinty, Senior Product Manager – Gas Turbine & Industrial SCR Systems, Mitsubishi Hitachi Power Systems Americas, Inc; Rand Drake
Today’s environmental regulations are continuing to put pressure on existing coal fleet resulting in
retirement and replacement using gas turbine technology resulting in the search for more cost effective
methods of satisfying the peaking power market, the fastest growing power market segment in the US
today. Historically, Aero-Derivative gas turbines have been used for simple cycle peaking application
at great cost when compared to the greater generation capacity of large frame gas turbines. This
presentation discusses the past problems resulting in the perception that achieving reliable and
consistent NOx reduction was not possible and the solutions eliminating these shortcomings. Today the
power industry and government regulating bodies accept Hot SCR technology for large frame turbines
due to demonstrated reliable plant operations resulting from advances in SCR system control system
technology. This presentation will look at some of the major equipment and engineering improvements
leading to recognizing large frame hot SCR systems as a viable cost effective alternative to the use
of Aero-derivative engines and will look as some of the characteristics associated with successful
application of such systems. This discussion will focus on fundamental SCR system design, catalyst
selection, ammonia vaporizing & distribution technology and tempering air systems, for Large Frame
Simple Cycle Gas Turbines.
E7.5 Delta Wing® Mixing System Retrofit for Improved SCR Performance
Clayton Erickson, VP Environmental Technology and Products, Babcock Power Environmental; Roderick Beittel, Riley Power Inc
Two, 500 MW coal-fired Riley Turbo boilers commissioned in 1982-83 were retrofit in 2003 with single reactor
SCR’s, utilizing a steam-heated anhydrous ammonia vaporizer with dilution air. The original
ammonia injection grid (AIG) consisted of 40 risers, each with a manual balancing valve, and 780
individual nozzles. The original AIG provided adequate ammonia distribution when clean and recently
tuned. However, the distribution was found to degrade due to variations in boiler operations and
fouling of the AIG risers, valves and nozzles. Regular disassembly and cleaning of these components,
followed by re-tuning, was required to maintain the target of less than 100 ppm ammonia in ash. The
ammonia injection rate was typically controlled manually due to issues with automatic control. In 2014,
the vaporizer system was replaced with a system using direct injection of anhydrous ammonia into
heated dilution air. The original AIG system with 40 risers and valves was replaced with eight injection
lances and valves, configured with a Delta Wing® static gas mixing system in the SCR inlet duct.
Acceptance testing showed an ammonia-to-NOx ratio standard deviation of 4%. Fly ash ammonia
values have been consistently much less than 100 ppm, with single-digit values typical. Improved
controllability of the new system allows ammonia injection to be operated in automatic to maintain
the NOx emission set point.
E7.6 Updates on the Performance of Selected Lime-based Circulation Dry Scrubbers
Shiaw Tseng, Marketing & Technical Manager, Graymont
Various circulation dry scrubbing (CDS) technologies are being utilized to efficiently remove multiple
air-borne pollutants emitted from solid fuel-fired electric generating units (EGUs), industrial boilers, waste
incinerators, cement manufacturing plants, lime kilns, pulp & Paper mills, iron & steel manufacturing
plants, and other facilities. This versatile technology, when paired with lime as the reagent, can
simultaneously remove SO2, SO3, HCl, HF, Mercury (Hg), and other trace pollutants present in
combustion flue gases. It also provides solid-fuels burning facilities with the ability to accommodate
fuels with higher sulfur contents, while fulfilling regulatory compliance requirements. Lime is a widely
available reagent utilized in flue gas treatments, steel manufacturing, mining, pulp & paper industry,
glass manufacturing, water purifications, wastewater treatments, construction and other applications.
To be presented are the process characteristics of the CDS technologies, recent developments, and
the performance data from several CDS installations that were recently brought into commercial
operations.
E7.7 SO2 Control Using Dry Sorbent Injection Technology with Hydrated Lime
Jerry Hunt, Specialist Flue Gas Treatment, Lhoist North America; Jim C Dickerman
Recent regulatory drivers necessitate emission reductions in various acid gas pollutants (SO3, HCl and
SO2) and dry sorbent injection (DSI) has become an attractive compliance option. Successful full
scale SO3 and HCl demonstrations, increasing understanding of DSI’s impacts on fly ash, and improved
hydrated lime designs combine to generate increased interest in calcium based sorbent compliance
solutions. Based upon these the new developments in DSI technology, as well as, improvements in
calcium based sorbents, Electric Generating Utilities (EGUs) and industrial boilers operators have an
increasing interest in evaluating calcium based sorbents for SO2 abatement. The enhanced physical
properties of Lhoist’s Sorbacal® SP and SPS optimized hydrated ime products have shown from 50-
90+% SO2 reduction with DSI technology over a range of applications. This paper will present data
from DSI demonstration testing for SO2 control at EGUs and other applications, using Sorbacal® SP,
Sorbacal SPS, and standard hydrated lime products