June 2015 - Power Air Quality Insights 211

“SO₃ Removal Options” is the “Hot Topic Hour” on June 18, 2015 at 10:00 a.m. CST

Additions to this website are encouraged in advance. Participants are encouraged to review this site prior to the meeting. Here is an overview of the issues and options:

Coal-fired power plants are making major decisions relative to reduction of SO₃. This overview is designed to help these plants focus on the issues and options which need to be addressed in order to arrive at the best decision. This overview leads into a Decision Guide which in turn is part of the complete Decision Program 44I Power Plant Air Quality Decisions (Power Plant Decisions Orchard).

China is among the countries finding that solution of their NO_x and SO₂ problems create sulfuric acid mist. The environmental impact is serious and has created an urgency for solution. Companies with the solution have a big opportunity to expand their worldwide reach. Plants which install NO_x control systems and scrubbers are creating sulfuric acid mist. The mist plumes are often more visible than the exhaust before the major air pollution control investments. Furthermore, the nearby structures can be quickly damaged by condensing acid mist.

This problem creates a major opportunity for a number of companies who found solutions to the acid mist problem when it arose in the U.S. Suppliers of processes, sorbents, catalysts, filters and heat exchangers have experience which is now applicable around the world.

This acid mist problem affects the design of all the other air pollution control equipment. So the solution knowledge empowers the international suppliers. In pursuit of the solution, suppliers have discovered ways to make the entire plant more efficient, so this knowledge is even more valuable.

The first knowledge need involves regulatory implications. SO₂ in the flue gas is converted to SO₃ in the catalytic reactor used for NO_x reduction. The stack gas is cooled in the scrubber and the SO₃ leaving the stack is mostly condensed sulfuric acid mist. It is small in total mass but very visible and also destructive to nearby buildings. The mist is often treated as particulate by regulators. Since limits on particulate are an order of magnitude lower than on SO₂, the regulatory impact is very significant. There are many unresolved issues on measurement and limits on the mist.

The solutions to the SO₃ problem are different for each of three air pollution control processes: Wet Calcium, Dry Scrubber and Hot Gas Filter.

Flow Sequence	Wet Calcium	Dry Scrubber	Hot Gas Filter
Fuel	High sulfur	Medium/low	Medium/low
Combustion	LNB, FGR, SNCR, Br	LNB, FGR, SNCR, Br	LNB, FGR, SNCR, Br but also CaCO₃
After Economizer	SCR with catalyst to deal with SO₃, NO_x and Mercury	ACI, SCR with catalyst to deal with SO₃, NO_x and mercury	Ceramic catalytic filter with DSI
Air Pre Heater	Sorbent injection for SO₃ and acid gas trim	Sorbent injection for SO₃ and acid gas trim	Extract all heat and reduce exit to 200^oF
Particulate	ESP or FF	Dry scrubber/FF	Already captured
SO₂	Wet calcium FGD	Captured with particulate	Already captured
Trim	Wet ESP	Not available	Mercury module

LNB= low NO_x burner, FGR= flue gas recirculation, Br= bromine addition with fuel. SNCR= selective non-catalytic reduction, CaCO₃ = pulverized limestone addition in furnace, ACI= activated carbon injection, SCR= selective catalytic reduction, DSI= dry sorbent injection, HE= heat exchanger, ESP= electrostatic precipitator, FF = fabric filter, FGD= flue gas desulfurization.

Prior to pursuing the solution, the decision maker needs to carefully review all the regulatory as aspects of the SO₃. These include:

· Does the regulation specify limits on total particulate including condensibles or just discrete particulate?

· Total particulate. SO₃ can easily add 0.03 lbs./MMBtu to the total particulate emissions.

· Local ambient air regulations including startup, shutdown and special situations in pristine areas or cities.

Fuel: Once the reduction target is determined, then a decision program can commence. Fuel is the first factor in the decision program. A fraction of the sulfur in the fuel is converted to SO₃. Therefore, the problem is directly proportional to the sulfur content of the fuel. Since the price of fuel is directly disproportionate to the sulfur content, the decision maker must weigh the fuel price against the investment cost of the selected system. There are in effect many decision trees affecting the ultimate decision. It is necessary to keep retracing steps from one decision tree to another.

Combustion: Since the creation of SO₃ and NO_x are a result of combustion, there are many decisions to be made relative to burners, flue gas recirculation and additives in the boiler. The hot gas filter option actually starts with capture of SO₃ with powdered limestone in the furnace. Boiler additives can be selected to minimize boiler fouling, oxidize mercury and for other purposes. The SNCR approach involves urea or ammonia injection into the furnace to either eliminate the downstream SCR or to supplement it. The reduction accomplished by means other than catalytic reaction reduces SO₃ formation.

After the economizer. The optimum temperature for catalytic reduction is 850^oF. Therefore, the SCR is generally located downstream of the economizer but prior to the air heater. The catalyst reduces NO_x but oxidizes SO₂ to SO₃. Catalyst manufacturers have developed products which minimize SO₃formation while maximizing NO_x reduction and mercury oxidation. The performance on each of the three pollutants plus cost and maintenance issues all serve to make the decision complicated.

If mercury is to be removed with ACI, a decision needs to be made whether to inject it ahead of the SCR or downstream. Most particulate filters are only capable of withstanding temperatures below 400^oF. Therefore, they are located after the air pre heater. The catalytic filter is able to withstand 850^oF and can be located prior to the air pre heater.

The catalytic filter with DSI or powdered limestone injection achieves high efficiency removal of particulate, NO_x and acid gases. There is less experience with this technology than the other two alternatives. Otherwise it has considerable advantage from the standpoint of cost and space requirements. There are a number of large companies entering this space. So the options are continuously changing.

The catalytic filter with DSI also removes the SO₃. The exit gas is clean. As a result, efficient heat exchangers can be utilized and boiler efficiency substantially increased.

Air Preheater: Plugging and corrosion in the air preheater are accelerated with the higher levels of SO₃ created in the SCR. One remedy is the injection of sorbents ahead of the air preheater. Unlike DSI, only a modest amount of sorbent is needed to reduce the acid dew point. Benefits include reduced maintenance and corrosion as well as the ability to extract more heat in the heat exchanger.

The air preheater capability is limited by the acid dew point. The injection of sorbents captures the SO₃ and enough of other acid gases to lower this dew point. Greater heat extraction can increase boiler efficiency by more than one percent. Proponents of this approach recommend it for most boilers and not just ones with SO₃ problems.

Particulate: A fabric filter or electrostatic precipitator generally follows the air preheater. Most plants use dry precipitators which do not remove the acid mist. The mist problem was first solved in the U.S. by adding wet electrostatic precipitators downstream of the scrubber. China has chosen WESPs for many of its problem installations. This is an effective but costly solution. It cannot be justified just on its ability to remove SO₃. However, there are arguments for its inclusion for other reasons.

One inexpensive approach is to use a wet calcium scrubber for both initial particulate capture and SO₂ absorption. A downstream wet precipitator is then used for trim. The disadvantage is that flyash and gypsum are mixed.

There is debate about the locations for dry sorbent injection. One option is to inject it just prior to the precipitator. Another option is to inject it prior to the scrubber. The purpose is to remove SO₃ but an additional advantage is that the sorbent is then fully utilized in the scrubber.

The air toxics rule for power plants in the U.S. originally set limits for total particulate including condensibles. With this definition the sulfuric acid mist became the most challenging pollutant for reduction. Just 10 ppm of mist was enough to cause particulate exceedances. Due to intensive opposition, the rule was changed just prior to promulgation and limits only discrete particulate.

Total particulate continues to be the measurement criterion for some state and local regulations and is the basis for measuring ambient air quality. States are presently tasked with reducing the ambient levels of fine particulate. Therefore the contribution of SO₃ has to be taken into account.

Most fine particulate is a reaction between acid gases and base compounds such as ammonia, sodium or calcium. Sulfuric acid mist is a toxic pollutant whereas SO₂ is not. Nearby the exhaust stack the distinction is important. However, relative to long term ambient air quality the sulfur from either compound becomes a particulate sulfate.

The decision maker needs to consider which regulations over the long term will govern his equipment selection. A more stringent regulation which is likely a few years from now has to be given weight in the analysis.

SO₂: Wet calcium FGD systems are very efficient in removing SO₂ but not in removing acid mist. In fact by cooling the gas they cause acid mist to fall closer to the exhaust stack. Dry scrubbers are less efficient SO₂ removal devices but do remove acid mist. The catalytic filter removes both.

Wet calcium FGD systems are the most popular choice because they use an inexpensive sorbent (limestone) and create a salable byproduct (gypsum). The other two options do not create gypsum. In China there are bricks and other construction materials created from the flyash/gypsum mix.

DSI injection ahead of the wet calcium FGD provides SO₃ removal and additional sorbent for SO₂ capture.

If the product is going to be sent to a landfill, it can be chemically fixed with lime addition. This is desirable to prevent leaching of toxic compounds. The salability of flyash and gypsum are two inputs in the analytic process. Landfill requirements and cost are another.

Trim: A wet electrostatic precipitator located in the top of the scrubber or as a standalone device will provide very high acid mist removal and also efficient removal of discrete particles. The precipitator market leaders are Chinese companies. Tough new particulate limits require change or replacement of the existing dry precipitators. So the addition of wet precipitators to solve the SO₃ problem and capture discrete particulate has been a popular solution.

Materials of construction for the WESP are a major cost factor. The price of nickel has fluctuated greatly. The attractiveness of the WESP approach is in part dependent on nickel pricing.

If the catalytic filter route is chosen, then there may be a need for trim with a mercury module. This is an expendable absorbent which may have a life of several years. It can be placed after the heat exchanger and before the stack. Alternatively, the catalytic filter can be operated at 600^oF rather than 850^oF and activated carbon added along with the DSI. The analysis must weigh the initial and operating cost of the two approaches.

Site Specific Issues: The physical layout of an existing plant is likely to be a cost factor in the analysis. If a catalytic filter can be installed with little change in ductwork while an SCR and dry scrubber fabric filter will require long duct runs and major demolition, then the catalytic filter will be economically attractive.

If the area has water problems, the dry scrubber/baghouse or catalytic filter will have advantages over the wet calcium approach. The expected remaining life of the plant is another major consideration. Sale of byproducts and cost of landfill are two additional site specific factors.

Decisions relative to SO₃ reduction involve many different general and site specific factors. The catalytic filter option is being more clearly defined each day. Opportunities for improving boiler efficiency while removing SO₃ should be widely considered. The McIlvaine Decision Guide to SO₃ reduction and Power Plant Air Quality Decisions Program will, therefore, be of continuing value.

OEMS and Consultants Purchase or Influence Nearly Half Of All Flow Control and Treatment Products and Services

In 2015 Original Equipment Manufacturers (OEM), Engineering, Procurement and Construction (EPC) companies, consultants and architect engineers will purchase or influence the purchase of air, gas, water and liquid flow control and treatment products and services valued at $147 billion. This represents nearly half all the purchases of these products.

Product	Industry Revenues ($ Billions)	OEM and Consultant Orders and Decisions ($ Billions)
Pumps	53	25
Valves	86	40
Liquid Filtration	46	20
Other Liquid Treatment	39	15
Indoor Air	11	4
Stack Gas Treatment and Flow	73	35
Monitoring	15	8
Total	323	147

Twenty thousand companies will average over $7 million in purchases and decisive influence. They include some of the largest EPCs who purchase $ billions to small OEMS with purchases of less than $1 million.

Identifying these companies, their products and their locations is a challenge made increasingly difficult by the continuing acquisitions and divestitures. In order to track this activity on an organized basis, McIlvaine has created a corporate identification number. All subsidiaries can then be immediately displayed with their products, services and locations. Product Analysis by Financial Entity

One active acquirer is CECO. Here is an example of how one finds the contacts for a location. (Alternatively you can start with products or locations.)

(More than 20 other subsidiaries are listed including those in the Netherlands and China. The acquisition of Peerless is not yet complete, so none of these locations is listed.)

The sales manager will want to analyze the potential for all the subsidiaries and can do so as follows.

CECO is a significant OEM purchaser of valves. One group also makes valves but only fiberglass, so they cannot supply their needs internally. Duall, Fisher, Klosterman, Bush Zhongli and HEE are all potential valve purchasers for scrubber systems. When you click on Duall, you see the products and the contacts:

Name	Title	Email	Telephone	Fax	Source
Name	Title	Email	Phone	fax	xxxx
xxxxxxxxxx	Purchasing Mgr.xxxxxxx.	xxxxxxx	xxxxxxxx	xx	xxxxx
xxxxxxx	Design Chemical Engineer	xxxxx	xxxxxxxxx	xx	xxxx
xxxxxx	General Manager	xxxx	xxxxxxxxx	xx	xxxx

The corporate identification approach is particularly valuable in pursuing opportunities in China. The multiple ways subsidiaries are listed and spelled makes it very confusing. So McIlvaine provides the corporate identification link for the Chinese subsidiaries in both English and Chinese.

English Name	Corporate Identifier	Name in Mandarin
Shanghai Da Gong New Materials	690	上海大宫新材料有限公司
Shanghai Dongfang Boiler Group	1287	上海东方锅炉厂
Shanghai Duomile Photoelectric Instrument	671	上海多米乐光电仪器有限公司
Shanghai Feng Cheng Machinery Engineering	687	上海峰晟机械设备有限公司
Shanghai Fengwei Knitting Needle Manufacturing	786	上海丰威织针制造有限公司
Shanghai Filtair Air Filter	732	上海飞特亚空气过滤有限公司
Shanghai Flow Valve & Fitting	1405	上海富乐阀门管件有限公

Siemens Awarded Record Energy Orders that will Boost Egypt’s Power Generation by 50 Percent

Siemens has signed contracts worth €8 billion for high-efficiency natural gas-fired power plants and wind power installations that will boost Egypt's power generation capacity by more than 50 percent compared to the currently installed base. The projects will add an additional 16.4 gigawatts (GW) to Egypt's national grid to support the country's rapid economic development and meet its growing population's demand for power.

Together with local Egyptian partners Elsewedy Electric and Orascom Construction, Siemens will supply on a turnkey basis three natural gas-fired combined cycle power plants, each with a capacity of 4.8 GW, for a total combined capacity of 14.4 GW.

Siemens will also deliver up to 12 wind farms in the Gulf of Suez and West Nile areas, comprising around 600 wind turbines and an installed capacity of 2 GW. The company will build a rotor blade manufacturing facility in Egypt's Ain Soukhna region, which will provide training and employment for up to 1,000 people. The facility is scheduled to go into operation in the second half of 2017.

SunEdison has been awarded an additional five solar photovoltaic projects in South Africa, totaling 371 megawatts (MW) DC. This award stems from the extended capacity announcement for the fourth bid round of the Renewable Energy IPP Procurement (REIPPP) Program organized by South Africa's Department of Energy (DOE), in which SunEdison previously announced that it had been awarded an 86 MW solar project. In total, SunEdison has won 457 MW across six solar power projects in South Africa's fourth round of the REIPPP Program.

The five solar power plants will be located in the Northern Cape and North West Provinces and are expected to produce enough energy to power the equivalent of more than 200,000 South African homes. Eskom, the South African national utility, will purchase the solar energy under a 20-year power purchase agreement.

Florida Power & Light Company (FPL) and Florida International University (FIU) announced a new partnership to build a commercial-scale distributed solar power facility that will both generate electricity for FPL’s 4.8 million customers and serve as an innovative research operation.

The project involves the installation of more than 5,700 solar panels on 23 canopy-like structures that will be built this summer in the parking lot of the university’s Engineering Center, just north of FIU’s Modesto A. Maidique Campus. Using data from the 1.6-megawatt solar array, faculty and students from FIU’s College of Engineering and Computing will study the effects of distributed solar photovoltaic (PV) generation on the electric grid in real-life South Florida conditions.

FIU students have already begun gathering information to be used in their research, including historical weather data and energy production and usage patterns. The research will take Florida’s unique weather conditions into consideration and help determine the types of technology that may be needed to ensure the grid’s reliability is not negatively affected by fluctuations in solar PV production due to clouds, thunderstorms and other variables.

Ormat Technologies, Inc. announced that its wholly owned subsidiary, Orandina I S.p.A., was selected through a competitive bid process and signed a $98.8 million engineering, procurement and construction (EPC) contract for a geothermal project in Chile.

Under the EPC contract, Ormat will provide two air-cooled ORMAT® ENERGY CONVERTER (OEC) for a high enthalpy reservoir. The project is scheduled to be completed by mid-2017.

Two Nova Scotian businesses have secured contracts worth $25 million as part of the first round of procurement awards on the Cape Sharp Tidal project.

Aecon Group Inc. and Lengkeek Vessel Engineering have been selected by Cape Sharp Tidal after a competitive tender process. Cape Sharp Tidal is a joint venture between Emera Inc. and OpenHydro.

Later this year, the project aims to deliver one of the world’s first tidal arrays, with the deployment and grid connection of two 16-meter turbines in the Bay of Fundy, each capable of generating 2 MW of electricity.

Aecon Group Inc. secured the contract for fabrication of turbine components. It will also develop a 1,150 ton capacity barge for OpenHydro, which will be used to deploy turbines on to the seabed for the Cape Sharp Tidal project, as well as other future tidal array developments.

The Bay of Fundy’s tidal resource is one of the most powerful in the world. Cape Sharp Tidal is seeking to use the initial demonstration array in 2015 as the first phase of a commercial scale project in the Bay of Fundy, which subject to regulatory approvals, will see the development grow to an output of 300 MW.

· Closure of Three Appalachian Power Coal-fired Power Plants in West Virginia and Two in Virginia

· BHEL wins Power Cycle Piping (PCP) Package Contract for 1,980 MW Thermal Power Project in India

· Ovivo awarded Contract for Power Plant Worth over $4 Million in Southeast Asia

· Contract awarded to Amec Foster Wheeler for CFB Power by Hyundai Engineering

· Siemens awarded Contract to supply Two SGT6-8000H Gas Turbines and Two Generators to Mexico

· APR Energy signs Two-Year, 35 MW Contract for New Power Generation in Botswana

· Egypt’s El Sewedy wins €785 Million Share of Siemens Power Plant Deal

· Talen Energy established as one of the Largest Independent Power producers in the United States

· Valves for Combined Cycle Power Plants was Hot Topic Yesterday (June 4)

On Thursdays at 10:00 a.m. Central time, McIlvaine hosts a 90 minute web meeting on important energy and pollution control subjects. These Webinars are free of charge to owner/operators of the plants. They are also free to McIlvaine Subscribers of Power Plant Air Quality Decisions and Utility Tracking System. The cost for others is $300.00 per webinar.

See below for information on upcoming Hot Topic Hours. We welcome your input relative to suggested additions.

DATE	SUBJECT	DESCRIPTION
June 18, 2015	SO3 Removal Options	More Information
July 2, 2015	Hot Gas Filtration	More Information
July 23, 2015	Mercury Removal Options	More Information