oct2013update

In 2014 operators of gas turbines will spend $10 billion for air treatment. This includes treatment expenditures for 90,000 MW of new systems. It also includes service and consumables for 1.4 million MW of turbine systems in place. These are conclusions reached in a special study conducted by the McIlvaine Company. Gas turbines are increasingly used for power generation by large utilities. They are also used for power and steam generation by a number of industries.

Expenditures for air treatment have been rising at close to double-digit rates. One reason is the successful competition with coal. Another is the willingness of operators to obtain better filtration of the inlet air. The third factor is tougher regulations on NO_x, particulate, VOCs and CO.

Gas Turbine Air Treatment Products and Services
Capital	Operating and Maintenance
Intake Housing
Weather Protection
Conditioning	Nozzles
Pre-filtration	Filters
Coalescers	Coalescers
Final Filtration	Filters
Tempering Air System (Single Cycle)	Dampers, Drives, Fan Parts, Seals
Duct Burner (Combined Cycle)	Burner Parts
Ammonia Injection Grid	Nozzles, Ammonia
CO Reactor	Catalyst
SCR	Catalyst
Process Controls	Sensors, Valves, Seals, Gaskets
CEM	Rata Testing, Protocol Gases, Instruments
Silencer	Silencer Parts
Stack

Although APC systems have been in operation on gas turbine (GTs) for many years and are proven to produce low emission rates (as low as 0.8 ppm NO_x with undetectable levels of carbon monoxide), there are many problems and issues unique to the control of air pollution from GTs that are far different than those faced by coal- or oil-fueled steam plants. For example, GTs that are operated as peaking units have rapid ramp rates that result in severe temperature and flow velocity changes. The SCR catalyst must be carefully selected based on the operating temperature. Then the balance between the cost of catalysts for different operating temperatures and the cost of cooling or dilution systems must be evaluated. If a CO catalyst is included in the design, it may have an influence on SCR catalyst performance. If the GT is also operated on oil when gas prices are high then the sulfur content of the oil must be considered (in regard to SO₂ to SO₃ conversion and the resulting ammonium bisulfate after the SCR) as well as vanadium content. Gas turbine exhaust is very turbulent and flow modification devices may be required to ensure good mixing of ammonia with the exhaust gas and uniform flow across the catalyst. Backpressure however leads to a reduction in power and temperature changes in the turbine.

The following speakers addressed the current issues related to GT emissions control.

Bill Gretta, VP for the Power Plant Solutions Division Eneractive Solutions, Inc., provided advice for single cycle SCR purchasers. Eneractive Solutions provides system design and optimization, overall SCR and CO catalyst system design, independent SCR catalyst management, SCR reactor inspections, evaluation and testing, ammonia system design and flow modeling. Bill made the following points:

§ Water injection can be used to reduce engine NO_x to 25 ppm but will increase CO.

§ With inlet of 25 ppm of NO_xand 90 percent removal requirement, ammonia slip will be an issue.

§ Tempering air adds to the complexity but the alternative of high temperature catalyst is expensive.

Bob McGinty, Senior Manager Business Development, SCR NO_x Control Systems at Mitsubishi Power Systems Americas, Inc., reviewed aspects of system design. Mitsubishi is considered one of the original pioneers of SCR systems and catalyst technology with more than 600 SCR systems operating worldwide. Mitsubishi catalyst technologies have been licensed globally with focus on the homogeneous honeycomb catalyst technology and joint development of plate catalyst technology. In 1989 Mitsubishi teamed with Corning to form the joint equity US-based catalyst company, Cormetech, to manufacture and supply extruded homogeneous honeycomb catalyst technology products.

Craig Sharp, Key Account Manager SCR/DeNOx Catalyst & Technology, Haldor Topsoe, introduced a new catalyst.

The CO and SCR catalyst can be combined into one module. There are four configurations including separate catalysts with the CO catalyst before or after the SCR catalyst and the combined SCR-CO or separate SCR catalyst followed by the CO catalyst. The combined catalyst offers high performance in less space.

Two recent developments in gas turbine air treatment are the expanded use of HEPA filters for gas turbine intake air and SCR with both CO and NO_x catalyst for the tail-end gas. Some dust that the inlet filter does not remove is going to deposit on the catalyst. A facility can use a very small catalyst pitch and save lots of money, but the increase in pressure loss along with deposition will increase operating cost and decrease electricity output. Therefore, the choice of inlet filter needs to be viewed initially in terms of catalyst pitch selection and then in terms of catalyst life.

First in California and now in other places, the stack gas emission limits are lower than the ambient air particulate matter concentration. In these cases, the inlet air filter becomes a key element in stack gas compliance. Gas turbine inlet ambient air undergoes a series of treatments. The initial treatment is to remove large weather-related contaminants e.g., snow, rain, etc. The humidity and temperature of the ambient air are also adjusted to increase the weight and therefore electrical output. This treatment can range from fogging nozzles to a full air conditioning system. Droplets are formed, coalesced and removed. Particulate filtration can be with a series of filters ranging from coarse to HEPA or it can take place with self-cleaning cartridges.

One alternative for NO_xcontrol during combustion is the low NO_x burner. Another alternate is water injection. Once the air has been mixed with the gas and combusted it passes through other systems in the gas path. In a combined cycle process there is likely to be a duct burner to adjust HRSG steam temperature. This can add to the pollutants. CO and NO_x catalysts are also utilized. However the accompanying ammonia injection can create ammonia slip which is regulated and also tends to foul the catalyst.

With single cycle systems many of the air treatment challenges are more complex as was pointed out by Bill Gretta in the webinar. If a low temperature catalyst is used, tempering air is needed. This creates a challenge in providing laminar flow to the catalyst. If high temperature catalyst is used, higher catalyst costs are encountered and higher maintenance is possible.

The air treatment needs are not static. The higher performance turbines are more likely to be compromised by small particles. The use of gas turbines and certainly the use of SCR are expanding to applications that are more challenging. The seawater and salts found in marine applications including floating production, storage and offloading (FPSO) units are examples.

Application in refineries in South America where inlet air quality may be low and fuel includes less than pristine liquids is another example. The rapid cycling of turbines complementing wind and solar is another newer challenge.

The changes and increasing complexity relative to gas turbine air treatment have demonstrated the need for a system to aid decision makers. McIlvaine will address this need with Gas Turbine Air Treatment Global Decisions Positioning System™ (GDPS). Details on this system will be forthcoming

You will need to enter your name and email address after clicking link to view recording.

Siemens recently launched the SGT 750 industrial gas turbine, capable of reducing NO_x to single digits. Siemens has already provided one new SGT 750 turbine for a CHP plant in Greifswald, Germany where it generates 37 MW. The feed gas for the power plant is imported from Russia through the Baltic pipeline and the gas is pre-heated before use in the turbine.

“The new industrial gas turbine is mainly aimed at combined heat and power applications, primarily for those customers who have a need for heat, and is able to perform well for the needs of a German municipality, for instance. It can supply about 37 MW electrical and 45 MW heat energy and its operational flexibility and short startup ability enables its use in highly-renewable energy markets,” said Dietmar Augele, Regional Sales Manager for Germany at Siemens. “We have the potential for single digits, below 10 ppm. It is an advanced model for this capacity range. It stays well below legislation limits.”

Markus Tacke, CEO Business Unit Industrial Power Siemens Energy, added that industrial turbines under development were capable of very low NO_x levels. “We are optimistic that we will be able to achieve 5 ppm. The Griefswald customer had specifications in terms of NO_x and we want to see the machines in the field in operation. We want to see long-term experience with the machines.”

GT-Series of Catalyst for Gas Turbines = Lower Pressure Drop and Improved Activity

The DNX^® GT-series is Haldor Topsøe’s newly-developed line of catalysts tailored for gas turbine service. The GT-series comprises a range of GT catalysts for NO_x reduction and GTC catalysts for CO oxidation. Topsøe’s DNX^® GT-series offers:

The GT catalysts feature an enhanced SCR activity which has been achieved through reformulating and changing the monolith structure of the original DNX^®catalyst. An increased specific surface area and a higher catalyst wall utilization have been achieved, which together with a larger open area provide an attractive combination of increased activity and lower pressure drop.

The GTC catalysts benefit from a dual functionality which makes the catalysts active in CO and VOC oxidation as well as in the SCR reaction. The dual function of the GTC catalysts makes it possible to locate the CO oxidation catalyst downstream of the SCR in the HRSG. The SCR can then be designed with excess ammonia slip which is subsequently eliminated across the GTC catalyst with the remaining part of the NO_x in the flue gas. This combined GT-GTC solution offers more than 40 percent reduction in SCR catalyst volume and more than 25 percent reduction in total pressure drop.

Johnson Matthey’s Stationary Emissions Control (SEC) group has successfully commissioned CO oxidation catalyst to reduce CO, VO and toxic emissions from four 200 MW simple cycle gas turbines. The turbines are part of GenOn Energy’s Marsh Landing Generating Station. Marsh Landing is capable of quickly generating up to 800 MW of electricity if renewable power sources, such as wind turbines and solar power are unavailable The gas-fired peaking facility incorporates quick-start 200 MW Siemens SGT6-5000F turbines that can reach full load in 12 minutes. Johnson Matthey’s oxidation catalyst was chosen by Mitsubishi Power Systems Americas, Inc. for integration into its hot SCR system. Benefits of the catalyst include fully brazed substrate to withstand turbulence and quick startup capability.

Altair Neptune represents the very latest in gas turbine inlet protection technology for the marine environment. The system utilizes the familiar three-stage vane/coalescer/vane approach, but represents a superior level of salt and water removal performance compared to traditional systems. Operating at velocities as high as 15 m/s (3000 FPM), the AltairNeptune filtration system allows greater flexibility due to its compact size.

Ahlstrom Advanced Filtration has installed a new laminator at its Fabriano plant to support the manufacture of high-performance composite media.

Ahlstrom adds that the media will be used for advanced filtration applications such as hydraulic, high-efficiency and industrial air.

The new laminator can utilize a variety of adhesives, such as polyurethane, copolymers and polyamides. The machine can handle many different types and sizes of substrates. In addition to wetlaid paper or glass, the laminator can process meltblown media, spunbond scrims, plastic mesh, or metal wires. The adhesive can be applied to either side of a structure, and the coating weight can be adjusted.

According to Ahlstrom, these flexible features allow the manufacture of high-performance composites with optimum physical integrity, for good processing performance, as well as minimum pressure drop. Specifically, the minimal amount of adhesive and the particular adhesive pattern help to achieve optimum air flow and maximum dust holding capacity.

Ahlstrom adds that in hydraulic filtration applications, the construction of laminated multilayer media will offer good added value. Traditionally, hydraulic filters consist of a 6-layer construction, including a pre-filter micro-glass media, a fine-filtration micro-glass media, spunbond scrims and wire mesh protection on both upstream and downstream side. These layers are individually fed and loosely co-pleated, which makes a pleating process difficult and slow, and causes a lot of material waste and potential for defects.

For the manufacture of high-performance hydraulic filters, Ahlstrom says that its ready laminated combination media will allow much simpler processing, offering cost savings and waste reduction.

Yara International ASA delivered strong second-quarter results, with a 21% increase in fertilizer deliveries, partially offsetting the negative development in commodity fertilizer prices. Global urea prices declined almost 30%, while value-added fertilizer prices were broadly in line with a year ago.

"Yara reports a strong second quarter with record deliveries," said Jørgen Ole Haslestad, President and Chief Executive Officer in Yara.

"While we have seen a considerable price decline for urea - almost 30% - our value-added product prices are broadly in line with a year ago, as continued strong food prices motivate farmers to optimize productivity with higher-efficiency fertilizer," said Jørgen Ole Haslestad.

Yara reports second-quarter net income after non-controlling interests of NOK 1,865 million (NOK 6.68 per share), compared with NOK 2,787 million (NOK 9.82 per share) a year earlier. Excluding net foreign exchange loss and special items, the result was NOK 7.98 per share compared with NOK 10.80 per share in second quarter 2012. Second-quarter EBITDA excluding special items was NOK 4,066 million compared with NOK 5,194 million a year earlier.

Yara fertilizer deliveries increased for all main product groups. Urea sales increased by 42%; reflecting higher sales of Qafco urea primarily in Brazil and North America, but also in the Mediterranean region. Compound NPK saw continued strong demand, and deliveries were up 30% with strong European and Asian core market growth. Nitrate deliveries were 14% above last year, mainly reflecting higher European sales.

Second-quarter nitrogen fertilizer industry deliveries in Europe were up 14% reflecting strong demand for immediate consumption, following poor weather in March. The European nitrogen fertilizer industry enters the 2013/14 season in Europe with lower stocks, in Yara's case 19% lower than a year ago. European farm margins remain strong, with somewhat lower cereal prices but significantly higher dairy prices than a year ago.

Ahlstrom, a global high performance fiber-based materials company, announces price increases in the fourth quarter of 2013 for its filtration materials globally. The price increases will be made to compensate for the continued rise in raw material costs such as specialty pulps, chemicals and energy as well as adverse currency fluctuations.

Prices of specialty fibers including mercerized pulp, cotton and glass, as well as energy and chemicals have continued to rise steadily over recent months.

The price increase will affect filtration materials produced by Ahlstrom globally. The level and timing of the increase will depend on the markets served, the raw material content of the product and the agreements in place. The increase will be up to 10%. Specific details will be discussed with each customer individually by the appropriate sales teams.

INDA’s Filtration International Conference and Exposition, the largest filtration event in the Americas, is returning to Navy Pier in Chicago, Illinois, taking place from 12-14 November 2013.

Over 130 exhibitors will be showcasing the latest filtration innovations, technologies and end products from around the world. More than 1600 key decision-makers from 30 countries will take part in the show that will be presenting new materials, roll goods, machinery, new technology and filter media components.

Dave Rousse, INDA President, said: “The annual Filtration event is truly a global venue bringing together everyone in the filtration value chain for three days of important business interactions and forward looking information. Filtration is one of the nonwoven industry’s fastest growing segments and Filtration 2013 will showcase the latest innovations from industry leaders.”

This year Filtration will offer three days of conference content, with the popular Filtration Air and Liquid Tutorials. The National Air Filtration Association (NAFA) will once again this year be presenting their Air Tutorial and Dr Christine Sun, Textile Research Associates, will be leading the Liquid Tutorial.

This year’s conference theme for Filtration is ‘Filtration: Protecting Health & Environment’. The keynote session sets the tone for this theme as Dr John D. ‘Jack’ Spengler, PhD, Akira Yamaguchi Professor of Environmental Health and Human Habitation, Harvard Public Health, will be discussing global climate change and the effects on human health.

McIlvaine Company will be creating a number of GdPS Route Maps. One will be on gas turbine air treatment. There will be decision stops at the various exhibit stands and at the speech locations which are relevant to the subject.