Presented at EUEC 2015: February 17, San Diego, CA. (in Session E5 & E6)
E5.1 The Benefits of High Reactivity Hydrated Lime in a Circulating Dry Scrubber
Curt Biehn, Manager, Marketing & Technical Services, Mississippi Lime Company; Mark DeGenova
Mississippi Lime’s High Reactivity Hydrated Lime has proven performance advantages in Dry Sorbent
Injection systems. The sorbent’s improved reactivity & in-flight capture of acid gases offers benefits
for tighter regulatory requirements or savings on annual delivered sorbent costs. This paper will review
the results of a 2014 test program conducted on a Circulating Dry Scrubber. During this test, the Utility
customer experienced significant benefits when campaigning HR Hydrate compared to the typical
hydrated lime used in their system, including lower hydrated lime feed rates & reduced ash disposal.
The results of this trial will show the economic advantage of using HR Hydrate over purchased or site
manufactured hydrated lime.
E5.2 Successful Operation of Flue Gas Humidification/Cooling Using Spray Nozzles Upstream of Dry Sorbent Injection (DSI)
Robert Van Durme, P.E., Key Account Manager, Lechler Inc.; Ashwin Patni, Lechler Inc.; Leon Lenertz,P.E., Xcel Energy
Xcel Red Wing is a 2 unit, 24 MW plant located in Red Wing, MN that burns processed municipal
waste as their fuel source. A DSI (Dry Sorbent Injection) system of dry lime injection is utilized to reduce
SO2. The plant experienced difficulties with the spray nozzles they used for gas cooling/humidification
upstream of the DSI system. System engineers wanted to eliminate wetting of the process and reduce/
eliminate the maintenance and energy costs of their air atomizing humidification system, while still
maintaining/improving their emission control process. A high pressure, hydraulic spray nozzle grid was
installed upstream of the dry lime injection grid in place of the previous air atomizing system to assist in
reducing gas temperature and improving lime reactivity. The system has been in operation for over 2
years. Emission performance, energy savings, and before/after results will be presented.
E5.3 Beneficiation of High Sodium Fly Ash
Michael Atwell, Market Development Manager, Solvay Chemicals
Solvay is testing ash samples to determine the impact of sodium sorbents on leachablity of metals and
on compaction of the ash. In addition we will be looking at various stabilization options and mixing
technologies to mitigate potential leachate concerns.
E5.4 Sulfur Dioxide Mitigation Using Hydrated Lime DSI & Humidification
Carl Laird, Sr.Technical Specialist – FGT & Glass Markets, Carmeuse Lime and Stone
For many utilities and industrial applications, dry sorbent injection (DSI) of hydrated lime
(Ca(OH)2) offers advantages over the wet or semi-wet flue gas desulfurization systems for
controlling the emissions of SO2, HCl, HF, SO3 along with assisting ACI in mercury capture.
These potential advantages include ease of retrofit, dry waste and low capital investment.
Injection of calcium reagents can occur anywhere in flue gas path from the furnace to the
particulate control equipment but the optimum location depends on the target pollutant and
flue gas conditions. Common injection points for DSI include the upper furnace, pre-SCR, and
the inlet or outlet of the air heater. These injection points can be single injection points to focus
on a particular pollutant or they can be combined to optimize the capture of multiple pollutants.
Carmeuse Lime and Stone participated in DSI trials using hydrated lime at several sites for acid gas
mitigation and assisting ACI in mercury capture. In this case, hydrated lime was injected at the air heater
outlet of two coal-fired boilers where duct humidification was utilized. This technology successfully met
the objective of reducing SO2 emissions of the plant to under 400 mg/Nm3. Results of these tests and
benefits of humidification will be discussed.
E5.5 Application & Benefits of SO3 Removal Upstream of the Ljungstrom® Air Preheater
Gus Shearer, Product Director, ARVOS Inc. LJUNGSTROM Division; Sterling M. Gray, PE, AECOMCorporation
Over 90% of U.S. coal fired utility boilers utilize Ljungstrom® air preheaters (APH). The APH design sets
the tail end flue gas temperature, which impacts the plant efficiency and the amount of pollutants
emitted per MW generated. It also influences the selection, design, cost, and efficiency of many
downstream technologies used to control emissions of particulates, mercury, and sulfur species. This is
particularly true for temperature sensitive processes. Past design practice limited the amount of SO3
condensed in the APH to minimize fouling and corrosion. However, the installation of SCR with wet FGD
has created plume opacity issues due to increased SO3 and theAECOM SBS Injection™ technology
is a demonstrated process for the selective removal of SO3 from flue gas by the injection of a sodium
carbonate solution. TheAECOM technology has been applied commercially and operating for over 10
years at utility plants totaling over 16,000 MW. Typical application data for SBS Injection™ installations
will be presented including full-scale field test data that illustrate and quantify the benefits of SO3
removal upstream of the APH. With SO3 removed, air preheater fouling can be better controlled
and additional heat can be recovered to improve efficiency. The presentation will review available
upgrades for Ljungstrom® air preheaters operating in low SO3 environments to lower gas outlet
temperature, increase boiler efficiency and improve availability.
E5.6 Dry Sorbent Injection History & Future Application
Keith Day, Business Development Manager, Nol-Tec Systems
This presentation will provide a time-line on the historical development and existing applications for
dry sorbent injection up to 2014. Each existing application will be briefly reviewed, including SO2, HCL,
Hg, SO3, and ESP conditioning. A summary of co-benefits in applying DSI for these existing applications
will be provided. One possible future DSI application will be the primary focus of this presentation. As
the WFGD, SDA and DFGD fleet mature, system upgrades are required due to normal maintenance,
fuel switching, or changing regulatory requirements. Adding DSI as an upstream or downstream SO2
control option may be an option for consideration versus adding expensive upgrades to existing
FGD equipment. One has to consider DSI for facility life extension, when faced with very expensive
maintenance outages or FGD upgrades. Can this technology help meet new operating conditions
and will it be economical for the near term? DSI has historically been viewed as a bridge technology.
Applying the technology today helps the facility meet existing regulatory requirements at low capital
expenditure. This was a consideration ten years ago when the smaller older units were looking for low
cost SO2 control. In the near future, it may be a similar consideration for plants faced with costly FGD
upgrades. With the future of coal-fired generation uncertain, will DSI be once again considered for
SO2 control, when used in conjunction with existing FGD system?
E6.1 Improved NOx Reductions in a Combustion Optimization System using a Novel Neural Network Training Algorithm
Steve Piche, Director of Research & Development, NeuCo; Daxhang Gu & Fred Pickard
Combustion optimization of fuel and air distribution in coal fired units based upon a neural network
approach has been used to reduce NOx emissions over the past 20 years. Critical to the reduction
of the NOx emissions is the quality of the neural network. To improve the quality of the neural network
model of NOx, a novel neural network training algorithm has been developed. The new algorithm
focuses on training a neural network model that provides an accurate prediction of the change in NOx
due to change in the fuel and air distribution. (Standard approaches focus on providing an accurate
prediction of the value of NOx rather than the change in NOx.) By focusing on the change in NOx,
models that are particularly good for combustion optimization can be developed. In addition, the
new algorithm not only provides a prediction of the change in NOx but also gives an estimate of the
uncertainty of the prediction. Using the prediction of the change in NOx and associated uncertainty
over a training set, an analysis can be performed to determine if sufficient data is available for properly
training the neural network. If sufficient data is not available, the analysis can be used to design a set
of parametric tests of the unit that will result in sufficient data. Results will be presented from a large
coal fired unit where a combustion optimization system, with a neural network that was trained using
the novel algorithm, was implemented.
E6.2 Novel Low NOx Emissions Solutions to Achieve 20 ppm NOx
Richard Conn, Sr. Director of Technology, Sunco-International Inc. Co. Ltd.; Jeff Shan, Sunco-International Inc.; Denis Fallon, Celanese Corp.
In the past year the Chinese government has promulgated much stricter NOx emissions for both
industrial and utility boilers, especially in certain designated high pollution regions. These more stringent
NOx emissions, coupled with increasing coal prices, make optimization of NOx reduction strategies very
difficult. In response to this challenge, Sunco-International Inc. has implemented novel, cost effective
low NOx solutions for minimizing NOx emissions in both industrial and utility boilers. These strategies
include low NOx combustion systems, SNCR and SCR for smaller size industrial boilers. NOx emissions
of less than 75 mg/Nm3 have been attained with industrial boilers using a cost effective combination
of low NOx combustion, SNCR and SCR. Sunco-International Inc. has applied these NOx reduction
technologies to both corner-fired and vertical slagging cyclone boilers in industrial applications.
E6.3 Elevated NOx Reduction & Combustion Optimization for Coal-Fired Utility Boilers by Improving Furnace Mixing
Mike Klump, Director of Plant Optimization, Mobotec LLC; Guisu Liu, Baiyun Gong, Joe Aletto, Chris Clemmer, Vivek Savarianadam & Pat Crotty
This paper describes a cost-effective advanced NOx reduction technology by improving furnace
mixing, which incorporates multiple elevation of air boxes placed on furnace walls. Each box has
multiple high-velocity air injection nozzles, with locations of these boxes and air jet angle determined
and optimized through CFD modeling. The technology also consists of high-momentum air jets to carry
reducing SNCR agent deeply into flue gas for NOx reduction. This is particularly relevant for larger
boilers where gas coverage is more challenging. CFD modeling technique is used to evaluate and
determine injection locations, injection velocity, and droplet size distribution. The paper also presents
one of our recent applications of this advanced system on a 500 MW utility boiler in Europe. This is a twintangential
boiler burning a blend of Columbian and Russian coal. Twelve air boxes were installed at two
elevations on front wall and rear wall. Three levels of SNCR air boxes were installed at higher elevations
on front wall to cover various temperature windows at different loads. In the meantime, secondary
air nozzles of burners were modified in order to maintain windbox pressure. CFD modeling was also
utilized to locate these boxes. More than 60% NOx reduction has been achieved in performance test,
and average NOx emissions was approximately 0.15 lb/MMBtu across a wide range of unit loads while
maintaining efficient combustion.
E6.4 LoTOx(TM) – Novel NOx control solution
Peter Studer, Chemical & Environmental Industry Program Manager, LINDE; Naresh J. Suchak, Monica Caldwell, Frank Fitch & Steve Finley, Linde; Bob Ferrell, AECOM
NOx removal using LoTOx technology is simple, elegant and requires almost no new processing
equipment. LoTOx can be configured to remove NOx from any process or exhaust gas streams at
the tail end to meet limits on stack emissions & can be integrated within existing wet/dry scrubbing
system or most air pollution control equipment. It has been commercially implemented on a variety of
process and gas exhaust streams & in many different configurations to attain NOx emissions far below
stringent limits stipulated by regulatory authorities. LoTOx is low temperature oxidation process that uses
ozone to oxidize NOx to higher oxides of nitrogen which are not only very soluble but also reactive.
So, these can be easily removed along with other hazardous pollutants in commonly used wet or dry
scrubbers without any modifications in upstream processes. Oxidation of NOx with ozone is not affected
by the presence of other contaminants such as acid gases and particulates, resulting in very robust
performance in treating dirty and difficult gas streams. Ozone is produced on-site and on demand
using oxygen and does not require storage of hazardous chemicals. We will review the basics of LoTOx
technology and hardware requirements for integration with multiple air pollution control systems in
treating exhausts from a variety of industrial processes, along with the process performances obtained
in treating these diverse exhaust streams & provide the basic economics of implementing NOx control.
E6.5 Low NOx Combustion with Novel Anti-Corrosion System for Wall-Fired Boilers
Jeff Shan, President, Sunco International Inc. Co. Ltd.; Richard Conn
Much stricter NOx emissions have been promulgated by the Chinese government in the past year for
both industrial and utility boilers, especially in certain designated high pollution regions. These more
stringent NOx emissions, coupled with increasing coal prices, make optimization of NOx reduction
strategies very difficult. In response to this challenge, Sunco-International Inc. has implemented novel,
low NOx combustion solutions for minimizing NOx emissions in utility boilers, while avoiding adverse
impacts such as boiler water wall corrosion. These strategies include advanced low NOx burners
and OFA systems, coupled with a unique rear wall anti-corrosion air supply system. NOx emissions
of less than 400 mg/Nm3 have been attained with firing medium volatile Chinese bituminous coal,
while reducing severe rear water wall corrosion in the combustion zone. Sunco-International Inc. has
successfully applied this low NOx reduction technology to other 350 MW front-wall fired boilers that
present inherent challenges for eliminating water wall corrosion due to reducing conditions.”
E6.6 Direct Measurement and Modeling of Sulfuric Acid Concentrations in Coal-Fired Power Plant Flue Gas
Brian Adair, Senior Chemical Engineer, Geosyntec Consultants, Inc; Dr. Brian Adair, Dr. Curtis Laush, Darwan Pursoo
A large Southeastern utility burning bituminous coal of increasingly high sulfur content is investigating
mitigation methods to reduce emissions of sulfur trioxide (SO3)/sulfuric acid (H2SO4) resulting in
increased stack opacity (“blue plume”) at several of their units. As part of their mitigation strategy, the
utility is testing real-time measurement tools to determine concentrations of SO3/H2SO4 in the flue gas.
Geosyntec’s custom-built FTIR spectrometer was deployed in late 2014 to measure concentrations of
sulfur species downstream of the ESP and the results are presented here. Results were consistent with
predicted concentrations based on fuel type, oxidation in the boiler and across the SCR, and removal
in the air preheater, and observed opacity. Since an FTIR was used, other species including NH3, NO,
NO2, H2O, CO, CO2, HCl were measured simultaneously, given the plant additional process data to
better understand effects of process conditions on flue gas chemistry. In addition, it was shown that, by
using plant process data (e.g. CEM SO2, load, flue gas flow rate, etc.) the H2SO4 concentration could
be accurately modeled, thereby giving the plant a choice of real-time monitor data and/or model
predictions to economically inject sorbent for efficient stack opacity control.