July 2015 - Power Air Quality Insights 217

Hot Gas Filtration Questions Replace Regulations as the Most Important Air Pollution Control Subjects

Regulations are normally the most important factors changing the world’s air pollution control decisions. However, advances in the ability to treat hot gases make technology questions the most important subjects for air pollution control purchasers in China, the U.S. and the rest of the world.

The regulations leave no doubt that existing precipitators on coal-fired boilers, kilns and furnaces will need to be replaced or upgraded to higher levels of efficiency. In addition, refinery catalytic cracker and precious metal mining and smelting plants are looking for new routes to separate high value products. So the stage is set for development of new technology to address these interests.

There are many new hot gas filter developments and no clear solution. The questions can be organized in two main categories: process and application.

Process		Application
Temperature: 850^oF, 400^oF, 325^oF, or 200^oF		Coal-fired boilers
Heat recovery		Coal gasifiers
NO_x removal		Cement and other kilns
Acid gas removal		Catalytic crackers
VOC removal		Furnaces and smelting operations
Product separation		Mining and rare earth recovery

There are hundreds of process questions involving which contaminants need to be removed and what heat recovery benefits can be achieved.

There are presently many operating and planned retrofit projects involving installation of synthetic filter bags in existing precipitator casings. This approach can be combined with sorbent injection ahead of the air heater to reduce the acid dewpoint. The heat exchanger can be modified to capture more heat and discharge 200^oF flue gas. Lots of potential advantages and questions arise about the benefits and approach.

· Would the temperature reduction by itself improve precipitator efficiency enough to avoid a bag retrofit?

· Can a lower cost bag, such as acrylic, be used as long as continuous temperature control is assured?

· How does this solution fit into the overall need to remove multiple pollutants?

Fibers	Shape and chemical characteristics?
Media	Woven, non-woven, membrane?
Bag design	Pleated, tubular, star?
Bag size	Diameter and length?
Cleaning mechanism	Pulse with high pressure or medium pressure, reverse air?
Components	Cages, seals?
Installation	Need for bag covers for membrane bags?

The selection is highly dependent on the particulate constituents. If the collector is part of a dry FGD system with spray drier or fluid bed scrubber preceding it, a large quantity of calcium sulfate will be captured. Dry sorbent injection creates the same challenge.

The most novel development is the catalytic filter which has now been proven to be commercial for glass plants, biomass combustors and mining. When this is combined with ammonia and dry sorbent injection, it is possible to remove particulate, acid gases and NO_x at 850^oF.

Another version of the catalytic filter using synthetic media and embedded catalyst operates at 350^oF and depending on the catalyst selected can remove NO_xor VOCs. Can the one device provide total removal of multiple pollutants or does it need to be supplemented by SNCR or other technology to meet the emission requirements?

Coal-fired boilers represent a multi billion dollar immediate potential for filter upgrades. Other applications are also significant. Many coal gasification systems with hot gas filters are presently under construction or planning. Refineries can potentially replace precipitators and recover more valuable catalyst with ceramic filters. NO_x control can also be included with the catalytic filter.

Product recovery is an important potential. Metal and ceramic filters are already in use in a variety of hot gas filtration applications where product recovery is the most important filter function. Rare earth recovery from flyash could be a big potential for hot gas filters.

The many questions and rapidly developing technology are being addressed by McIlvaine with a holistic approach. There are multiple decision systems. Within each system are decision guides to allow the user to focus on specific aspects. Most of this is contained in 44I Power Plant Air Quality Decisions (Power Plant Decisions Orchard). Despite the title, the decision system does cover the range of hot gas applications in many industries. It includes webinars, summaries, fabric filter and precipitator newsletters and many other decision tools.

The per capita rainfall in China is only 25 percent that of the U.S. Large scale industrialization has necessitated major expenditures to reduce water use. The Zero Liquid Discharge (ZLD) concept is now viewed as an attractive solution for coal-fired power plants, coal-to-chemicals, refineries and other heavy industry.

China does need international technology. Several U.S., Japanese, and European companies are pursuing this market.

The main sources of contaminants are from the raw water reverse osmosis (RO) plant and the cooling tower blowdown streams. These effluents are first mixed in an equalization tank before further treatment (Figure 1).

Combined wastewater is rich in contaminants like oil and grease, volatile organic compounds and has a relatively high Chemical Oxygen Demand (COD) and Total Dissolved Solids (TDS) of about 16,000 mg/l.

McWong: Mengda New Energy Chemical Co. Ltd contracted with McWong for a coal-to-chemicals ZLD system. The overall capacity of this project is 13,200 m³/d including water from the project's own wastewater equipment and discharged wastewater from water pumping stations and desalination stations. McWong utilized its own patented zero-discharge process package (UF + RO + vibrating membrane + multi-effect evaporation concentration) technology to achieve zero discharge and recycle coal chemical industry wastewater.

IDE: The company is involved in desalination but can provide ZLD plants. A hybrid system has been installed at the Tianjin power plant, 200 km northeast of Beijing. The plant provides high quality drinking water for the local population, as well as industrial boiler makeup and process water for the power plant. The system is powered by waste heat from the power plant, thereby reducing the net greenhouse gas emission and reducing energy costs.

MHPS: Mitsubishi Hitachi Power Systems has a spray drier which uses the hot flue gas to dry the power plant sludge. This results in dry disposal instead of ponds and potential contamination. It is a low cost approach for coal-fired power plants. There are 1,000 boiler systems in China operating wet flue gas desulfurization systems. The spray dryer approach can be combined with the use of treated municipal wastewater as the raw water source. This results in a net reduction in water contamination rather than just avoidance of additional contamination.

Amazon Web Services to Build North Carolina’s First Utility Scale Wind Farm

Amazon Web Services, Inc. (AWS), an Amazon.com company announced that it has contracted with Iberdrola Renewables, LLC to construct and operate a 208 megawatt (MW) wind farm in Perquimans and Pasquotank counties, North Carolina, called the Amazon Wind Farm US East. This new wind farm is expected to start generating approximately 670,000 megawatt hours (MWh) of wind energy annually starting December 2016, or enough to power more than 61,000 U.S. homes in a year. When completed, it will be the first utility-scale wind farm in the state of North Carolina, with the energy generated delivered into the electrical grid that supplies both current and future AWS Cloud data centers.

In November 2014, AWS shared its long-term commitment to achieve 100 percent renewable energy usage for the global AWS infrastructure footprint. In April 2015, AWS announced that approximately 25 percent of the power consumed by its global infrastructure was from renewable energy sources with a goal of increasing that percentage to at least 40 percent by the end of 2016.

Fourth Major Duke Energy Solar Facility Begins Construction in North Carolina

Construction has started at Duke Energy's solar facility at the Marine Corps Base Camp Lejeune in Onslow County, N.C.

The 13-megawatt (AC) project is Duke Energy's first solar facility at a military base. Covering 100 acres, the facility is the largest solar installation on a military base in North Carolina. It will be owned and operated by Duke Energy Progress (DEP) and is expected to be online in 2015.

In addition to the Camp Lejeune project, Duke Energy is underway on a $500 million solar expansion in North Carolina. The company is currently building three solar facilities in Bladen, Duplin and Wilson counties, which are expected to be operating by the end of the year, and will have a total capacity of 128 megawatts.

Crowder Construction Services, based in Charlotte, is serving as the engineering, procurement and construction contractor. The project will use approximately 54,000 monocrystalline solar panels supplied by SolarWorld Americas. GE's Power Conversion business will supply its Brilliance inverters to be built out of its Pittsburgh facility.

California’s First Commercial Solar Desalination Plant to Bring Freshwater to the Central Valley

HydroRevolution^SM, a California subsidiary of WaterFX™, announced plans to build a commercial solar desalination plant in the Panoche Water and Drainage District in California's Central Valley. Once constructed, HydroRevolution^SM will provide a highly sustainable water source to local water districts by using solar energy to recycle salt impaired water into freshwater. This technology will be the first of its kind in the Central Valley but the company hopes this project is merely the first step in revolutionizing the way California uses water.

The HydroRevolution^SMplant will utilize Aqua4™ technology developed by WaterFX™. The system is a concentrated solar still that uses large solar arrays to capture solar thermal energy from the sun. The sun heats mineral oil that then flows to the Multi-effect Distillation system (MED) that evaporates freshwater from the source water. Over 90 person of the freshwater is recovered in this process while the briny remainder can be further treated to produce minerals and salts as useable solid co-products.

Meritage Homes and SunPower are now offering high efficiency solar power systems combined with energy storage technology at the 42-home Pinnacles at Stonebrae community in Hayward, CA.

SunPower® solar power systems are available as an option at Meritage Homes communities across the U.S. The systems use high efficiency SunPower solar panels, which produce 70 percent more energy in the first 25 years than conventional solar technology, according to tests conducted by the U.S. Department of Energy's National Renewable Energy Laboratory. At the Pinnacles at Stonebrae community, SunPower is also offering advanced energy storage solutions from San Francisco-based Sunverge Energy.

SunEdison and Advanced Microgrid Solutions Join Forces to Finance and Deploy 50 MW of Energy Storage for Southern California Edison

Advanced Microgrid Solutions (AMS), a developer of customer-sited energy storage systems that create Hybrid-Electric Buildings™, and SunEdison, Inc., the world's largest renewable energy development company, announced they have signed a joint development agreement to finance and deliver 50 megawatts of energy storage for Southern California Edison (SCE) under long-term capacity contracts. Once operational, these AMS projects are expected to be the first storage assets to be acquired by Terraform Power, Inc.

The storage system contracts were awarded to AMS as part of SCE's 2013 Local Capacity Requirement solicitation, and will be built on commercial and industrial customer sites throughout the West Los Angeles Basin.

The AMS-SunEdison partnership combines Advanced Microgrid's innovative designs and technology partnerships with SunEdison's development and financing expertise. The first fleet of energy storage systems is expected to begin commercial operation in 2016 in Irvine, CA.

· Black Hills deconstructing Ben French Coal-fired Power Plant near Rapid City, SD

· Duke Energy selects EPRI to launch Coal Ash Recycling Technology and Market Study

· Pollution Controls for Iowa Coal-fired Power Plants under a Clean Air Act Settlement

· Pakistan and China working on 120 MW Power Plant in Muzaffargarh, Punjab, Pakistan

· GS Power (Korea) selects GE 7HA.02 Gas Turbine and Clutched Steam Turbine for Combined Cycle Power Plant in Anyang, Korea

· GE Power & Water wins Outage Services Work for DTE Energy’s Fermi 2 Nuclear Power Plant

· U.S. requires Arizona and New Mexico Plant Owners to reduce Emissions at Four Corners Power Plant

· “Mercury Removal Options” is the Hot Topic Hour on July 23, 2015 at 10 a.m. CDT

· Gas Turbine Emission Control and Exhaust Systems is the Hot Topic Hour on August 6, 2015 at 10:00 a.m. CDT

We will continue to expand this summary and to link to new articles and case histories on a custom website. We are seeking contributions from the industry. Please contact us and we can coordinate your contribution (rmcilvaine@mcilvainecompany.com).

As you can see from the Route Map and Summary, we are linking to our previous Hot Topic Hour presentations and some supplemental material. We have addressed some issues where there is new information. We have not addressed many key segments such as silencers, diverters, options for D.O. catalysts and duct burners.

Over the next few weeks we will be adding background data on all these subjects (see Table of Contents in the Route Map and Summary). During the Webinar, we will be hearing from many people who will summarize with one or two slides the more detailed information which is found in the database.

There are many issues and options which vary by industry and geography. All are included in a comprehensive database which is part of Gas Turbine & Combined Cycle Decisions. For the next few weeks this database will be accessible to non subscribers at

Subsequent to the webinar, this website will no longer be freely accessible. It will be part of the Gas Turbine and Combined Cycle Decisions. This includes a password protected website. Power plants can register for free. However, there is a charge for others.

On Thursdays at 10 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
August 6, 2015	Gas Turbine Emission Control	More Information
August 20, 2015	Total Solution Options	More Information