Jansen Combustion and Boiler NEWSLETTER Briefs

In this issue: Boiler MACT and Update on Biomass Boiler Combustion System Upgrades

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Contents:

• Boiler MACT – How Combustion Improvements Help Meet Requirements
• Superheater Upgrades to Increase In-House Power Generation
• Jansen Presence at International Chemical Recovery Conference (IChRC) in Williamsburg, VA
• Witnessing a Revival in Energy-from-Waste Industry
• Update on Biomass Boiler Combustion System Upgrades
• Jansen Projects in Canada
• News Briefs
• Jansen at International Biomass Conference & Expo
• “Combustion Troubleshooting” Article Published in CanadianBIOMASS Magazine
• Receive Our Newsletter by “snail” and E-mail
• Boiler House Cartoon
• Biomass Boiler Workshop: New Orleans, June 10-11

Boiler MACT

How Combustion Improvements Help Meet Requirements

A new EPA ruling came out April 29, 2010 and is to be finalized by the end of 2010. The ruling’s purpose is to limt hazardous air pollutants from industrial, commercial, and institutional boilers and process heaters.

What is Boiler MACT?

One outcome of the 1990 Clean Air Act (CAA) was the formation of National Emissions Standards for Hazardous Air Pollutants (NESHAP) to regulate air pollutants that are not covered by the National Ambient Air Quality Standards (NAAQS). There are 188 Hazardous Air Pollutants (HAPs) that are covered. The EPA is tasked with determining the Maximum Achievable Control Technology (MACT) and establishing permit limits for HAPs control for each source category (Boilers, Kilns, Dry Cleaning Units, etc.). Boiler MACT refers to rulings for industrial, commercial, and institutional boilers and process heaters that have the potential to emit more than 10 tons per year of any one HAP or 25 tons per year of any conbination of HAPs, have a heat input rating of >10 MMBtu/hr, and can burn solid, liquid, or gaseous fuels.

The EPA promulgated the initial Boiler MACT rules in 2004 with a 3-year compliance period. However, on June 8, 2007, the US Court of Appeals vacated the ruling on the basis of complaints that portions of the ruling were not stringent enough, not inclusive enough, and required better definition of fuel classifications. A new ruling came out for comment on April 29, 2010, and is to be finalized by the end of 2010.

 

What Pollutants are Covered?

Considering the complexity of monitoring 188 pollutant species (ranging from Acetaldehyde to Xylenes), a handful of surrogate species have been selected for regulation in boilers, including emissions of particulate matter (PM) for heavy metals, carbon monoxide (CO) for organic compounds, and hydrochloric acid (HCl) for acid gases. Regulations for emissions of mercury (Hg) and dioxins/furans have also been proposed. These are in addition to existing NAAQS limits that may exist for PM2.5, PM10, sulfur dioxide (SO2), CO, nitrogen oxides (NOx), ozone (O3), and lead (Pb).

What Pollutant Emission Limits were Proposed?

The EPA has reviewed available data to determine the top 12% emission level performances for each surrogate pollutant on which to base future limits. The critical emissions limits that have been proposed that may be difficult for biomass-fired boilers to comply with are CO (560 ppm at % O2; or 0.465 lb/MMBtu), PM (0.02 lb/MMBtu or 0.01 grains/dscf at 7% O2), and dioxins/furans (0.004 ng/dscm at 7% O2).

How Can Combustion Improvements Help Biomass Boilers?

Intense mixing of fuel and combustion air, as well as improved control of fuel-to-air ratios and air distribution can drastically lower CO emissions. Installation of Jansen air system upgrades on existing biomass-fired boilers typically results in at least a 50% reduction in CO emissions. Improved combustion also reduces the total PM that exits the furnace from entrainment of ash and unburned fuel. Lower excess air operation due to improved combustion air delivery also reduces flue gas volumetric flow to the PM emissions control equipment, resulting in improved PM collection efficiency. Jansen has seen reductions in PM emissions of 30% or greater as a consequence of combustion air system upgrades. Care must be taken in the combustion system design to avoid increasing NOx emissions beyond permit limits as a consequence of more intense fuel and air mixing. Reductions in excess air operation may be required to compensate for the greater availability of oxygen to react with nitrogen when mixing is enhanced.

What are CISWI Requirements and What Boilers Qualify?

Another EPA ruling to be aware of and that may impact owner/operators of biomass-fired boilers is for Commercial and Industrial Solid Waste Incinerators (CISWI). There is the potential that boilers burning certain solid fuels, such as paper mill sludge, construction and demolition (C&D) wood, tire-derived fuels (TDF), old corrugated container (OCC) rejects, etc., could be classified as solid waste incinerators and be required to meet a different set of air pollutant regulations. CISWI rules have additional emission limits for NOx, SO2, cadmium (Cd), and lead (Pb) that are not covered by Boiler MACT rules. Combustion improvements will also likely be required on these units that are classified as solid waste incinerators since the CO limit is lower than required by Boiler MACT.

How Can Jansen Help?

Jansen can assist boiler owners/operators to determine how Boiler MACT (or CISWI) regulations impact their boiler and provide an evaluation of the boiler’s combustion characteristics. If operational improvements are not sufficient to meet the new emissions requirements, Jansen can provide combustion system upgrades and team with pollution control equipment providers to help comply with the new regulations.

• Read More about Jansen Combustion and Boiler Technologies, Inc. Services: Boiler MACT
• Read More about Jansen Project Capabilities: Boiler MACT and CISWI Compliance
• For further information and specific inquiries, please contact John La Fond at 425.952.2832 or Arie Verloop at 425.952.2825

 

Witnessing a Revival in Energy-from-Waste Industry

Municipal Solid Waste and Refuse Derived Fuel

The Energy-from-Waste (E-f-W) industry consists of facilities that burn municipal solid waste (MSW), refuse derived fuel (RDF), construction debris (CD), and sometimes biomass fuels in order to dispose of these waste materials. Typically, these facilities also convert combustion heat to produce steam and generate electrical power.

Recently, the E-f-W industry has experienced a surge in activities that is caused by both economic and political driving forces as well as popular trends, namely: 1) to reduce materials going to landfill, 2) to create power from renewable energy sources, 3) to offset the high cost of fossil fuels, and 4) to achieve more stringent air emissions limitations.

Improvements in the economic disposal of these waste fuels in combustion furnaces
is addressed in projects such as:

• Expanding the waste fuel burning capacity in existing furnaces.
• Improving the efficiency of the facility’s steam and power generation.
• Reducing metal corrosion rates and improving effective life span of the equipment.
• Improving air emissions through improved combustion and/or application of emissions control technologies.

In recent years, Jansen has participated in the revival of the E-f-W industry by carrying
out the following projects:

• Superheater corrosion analyses and design.
• Feasibility studies for boiler fuel conversion (from prior fuel to MSW/RDF).
• Review of process/combustion design factors, pressure part evaluations, and circulation studies.
• Computational Fluid Dynamics (CFD) modeling of combustion performance and heat transfer characteristics.
• ASME Boiler and Pressure Vessel Code “S” pressure part design and supply.
• Efficient combustion air delivery systems, i.e., overfire air (OFA) upgrades.

Jansen Presence at International Chemical Recovery Conference (IChRC) in Williamsburg, VA

Jansen’s representatives at the recent International Chemical Recovery Boiler Conference (IChRC; held the week of March 29 in Williamsburg, Virginia) included Dr. Allan Walsh, Technology Development Leader and John La Fond, Manager, Process Technologies.

Dr. Walsh’s participation in the Conference and its preparations were multifold, as he was the Technical Program Co-Chair (overseeing the technical content and quality of numerous conference presentations), in addition to co-authoring and presenting three papers. These papers are:

1. Evaluation of Superheater Corrosion in a Recovery Boiler; by Allan Walsh and Lee Kingma, Joel Young, Uday Bhagwat of Visy Pulp & Paper, Tumut, NSW, Australia.
   The paper evaluates corrosion that was observed in the lower bends of the secondary superheater and in straight sections of the tertiary superheater at the Visy Recovery Boiler near Tumut, New South Wales, Australia. Several alternative technical solutions were evaluated to remedy the problem. The best approach to solving the superheater corrosion was found to be upgrading the superheater tube material as well as implementing a plan to reduce the amount of potassium in the mill’s liquor system.
2. Evaluation of Water Flow in Floor Tubes of Recovery Boilers with a Decanting Hearth; by Allan Walsh, Marcel Berz, and Steve Campbell, all with Jansen.
   The paper presents results from the application of Jansen’s ultrasonic flow monitoring (UFM) technique to measure water velocities in wall and floor tubes of eight different recovery boilers with decanting hearths. The nature of the design of these boilers is such that front and rear wall tubes that are closest to the side walls (so called corner tubes) will generally receive less heat flux than other wall tubes, thereby resulting in lower circulating water flow. This could potentially have a detrimental impact on water/steam circulation conditions.
   The paper provides a discussion and assessment of these potentially detrimental effects.
3. Investigation of Dissolved Gases in Smelt; by Allan Walsh.
   Historically, smelt characteristics such as composition and temperature have been used when attempting to correlate changes in smelt viscosity and a lack of fluidity. However, these smelt properties would only seem to explain a relatively small change in viscosity. In studies, dissolved gases are known to increase viscosity in other materials by orders of magnitude. Measurements of the smelt from one recovery boiler indicated that it contained about 10 ft³ of dissolved carbon dioxide and carbon monoxide per cubic foot of smelt. The paper makes an initial exploration of this smelt property that may hold the key to overcoming problems with poor smelt fluidity.

 

Jansen Combustion and Boiler NEWS Briefs

Since our last newsletter (Fall 2009), Jansen has conducted the following process and design engineering projects in the Forest Products, Independent Power Producers, Energy-from-Waste, and other industries (several are in progress):

• Combustion system upgrades for biomass boilers.
• Biomass and RDF boilers engineering evaluations.
• Chemical recovery boiler performance evaluations and capacity studies.
• Recovery and biomass boiler evaluations to meet power generation upgrades.
• Design of injection nozzles for DNCG disposal in biomass boilers.
• Boiler circulation studies and UFM data collection.
• CFD modeling of biomass, chemical recovery, MSW, and RDF-fueled boilers.
• Boiler operational fine-tuning and optimization support.
• Recovery boiler operation procedures review and operator training.

This work was conducted, or is currently in progress for the following companies:

• AbitibiBowater
• Boise
• Cariboo Pulp & Paper Company
• Canfor Pulp Limited Partnership
• Chester Wood Products, LLC
• Clearwater Paper
• Domtar Inc.
• Fortistar Biomass Group
• Georgia-Pacific LLC
• Glatfelter
• International Paper Company
• Kimberly-Clark
• MeadWestvaco
• Minnesota Power
• NewPage Corporation
• Neucel Specialty Cellulose
• Port Townsend Paper Corporation
• Propal S.A.
• Smurfit-Stone Container Corporation
• Tolko Manitoba Kraft Papers
• Wheelabrator Technologies
• Weyerhaeuser Company

 

“Combustion Troubleshooting”

Article Published in CanadianBIOMASS Magazine

A Jansen authored article was published in the January/February issue of CanadianBIOMASS Magazine,
titled: Combustion Troubleshooting. The article discusses the combustion of solid biomass fuels, boiler operational goals, symptoms of poor combustion and their root cause(s), and upgrading combustion systems to remedy combustion problems. The article is based on Jansen’s experience of conducting performance evaluations of over 300 industrial biomass boilers, worldwide, and supplying combustion system upgrades on 55 solid biomass-fired boilers.  Read the article here

 

Jansen Projects in Canada.

In Canada, the department of Natural Resources is implementing the Pulp and Paper Green Transformation Program that was first announced early in 2009. Based on production of black liquor in Canadian mills, a total of CAD$ 1 billion is being made available to these mills for capital projects that have a positive impact on the environment, energy efficiency, and expanded use of renewable fuels.
Recently, Jansen has been awarded several projects that are supported by the Green Transportation Program and many more are currently under consideration.

 

Update on Biomass Boiler Combustion System Upgrades

Since the late 1990s, Jansen has designed and supplied combustion system upgrades on over 55 biomass boilers. Currently, projects are under contract for four additional units, with planned installations between July and November this year.

Typically, a combustion system upgrade includes modifications to the biomass fuel and/or air delivery systems, particularly the fuel delivery spouts and overfire air (OFA) supply, as depicted in the sketches to the right.

Further detailed information of the Jansen approach and experience in upgrading combustion systems of biomass fired boilers, including OFA upgrades, can be found on our website (www.jansenboiler.com) with detailed project descriptions and past Newsletter articles.

Readers may wish to attend one of Jansen’s Biomass Boiler Workshops.  As has been a tradition for ten years, again in 2010, biomass boiler workshops will be held in two locations: New Orleans (June 10-11) and Minneapolis (September 16-17).

 

• Read More about Jansen Combustion and Boiler Technologies, Inc.: Project Capabilities: Biomass Boiler Combustion System Upgrades

 

Boiler House Cartoons on Jansen Website

A collection of boiler house cartoons can be viewed on our website: www.jansenboiler.com.

Some 30 cartoons by Gordon Stevens shown previously in this newsletter are presented on the site.

Each cartoon depicts a humorous situation with people and equipment in the boiler house. As you will agree, Gord has the rare insight to find humor in the operation of power and recovery boilers and we hope you enjoy his cartoons as much as we do.

 

Superheater Upgrades to Increase Power Generation

In recent years, many industrial plants have been planning or have implemented projects to increase in-house electrical power generation rates. In particular, projects are being identified to increase the steam output, pressure, and/or temperature of existing boilers. These units may have been “underperforming” from their original design or their performance and efficiency can be improved after making modifications.

Readers may be interested in a technical paper, titled: Boiler Upgrades to Increase In-House Power Generation, presented by Jansen at the TAPPI 2008 Engineering, Pulping & Environmental Conference.

The paper discusses the following topics:

• Strategies to Increase In-House Power Generation.
• Boiler Steam Conditions to a New Steam Turbine Generator.
• Boiler Steam Conditions to an Existing Steam Turbine Generator.
• Maximizing Boiler Steam Production from Lower Cost Waste Fuels.
• By Improving Combustion
• By Increasing Thermal Efficiency with Additional Economizer Surface

The paper provides process technical data to help the reader make more informed decisions on whether to pursue a potential project in this area. The information in the paper is based on recent Jansen superheater and economizer upgrade projects on biomass, chemical recovery, and Energy-from-Waste (E-f-W) industry boilers. Particular case history descriptions are included on this page.

• Read More about Jansen Combustion and Boiler Technologies, Inc.: Project Capabilities: Superheater Corrosion Prevention

 

Boiler A. Biomass Boiler Superheater Replacement

In 2008, Jansen supplied a replacement superheater for a combination hog fuel and natural gas fired boiler with the purpose to increase the boiler’s final steam temperature. The unit has a maximum continuous rated (MCR) steaming capacity of 600,000 lb/hr at 825°F and 1,020 psig but was unable to achieve this temperature. With the superheater replacement, the goal was to increase final steam temperature to 925°F (760°F was typical) over a wide range of steam flows when firing a combination of hog fuel, tire derived fuel (TDF), cotton seed, and natural gas, or on natural gas alone. With the
new superheater, these performance goals have successfully been met.

After 18 months of operation, the unit was taken down for a maintenance outage this past April. An inspection of the overall mechanical condition of the superheater found to be in very good condition, other than a few minor items that are commonly found and repaired during inspection outages.

 

Boiler B. Recovery Boiler Process Evaluation

Jansen conducted a preliminary evaluation of the performance and capacity of a large recovery boiler with an upper steaming capacity of over 800,000 lb/hr at 670 psig and 670°F. After an earlier upgrade, the maximum allowable working pressure (MAWP) of the unit had been “rerated” to 900 psig. Currently the mill is evaluating technical solutions to increase the boiler’s steam temperature and pressure up to its maximum potential capacity in order to optimize in-house power generation from a new turbine generator.

Jansen evaluated the liquor burning capacity and performance of the unit as well as superheater design factors and performance. Design concepts were developed to upgrade the unit’s combustion system to reduce carryover and meet significantly higher final steam temperature and pressure from a replacement superheater. As part of the evaluation, Jansen conducted a visual inspection of the superheater during a recent annual boiler outage (see photo above). The purpose of this inspection was to verify the arrangement and condition of the existing superheater, headers, and supports and make measurements of critical dimensions.

 

Boilers C and D. Co-gen Project at West Coast Pulp Mill

Jansen is conducting process engineering studies to make an assessment of the feasibility and capital cost to increase steam production rates and temperatures of a hog fuel boiler and a chemical recovery boiler in a pulp & paper mill on the west coast. The mill is planning to install a turbine generator with electrical power production  capability that is significantly higher than the two boilers’ current capabilities

 

Attend Our 2010 Biomass Boiler Workshops

• New Orleans, Louisiana, June 10-11, 2010
• Minneapolis, Minnesota, September 16-17, 2010

Since 2000, these workshops have been attended by some 600 representatives of numerous plants in the
Pulp/Forest Products Industries, Independent Power Producers and Energy-from-Waste Industry.
The workshops consist of presentations about new technological developments and results to improve the operating performance, waste fuel burning capacity, efficiency, and fuel economy of biomass-fired boilers (mostly stoker-fired). In addition, the program will include troubleshooting and problem solving discussions of challenges that attendees bring to the workshop. Participants will benefit by: 1) learning about the current retrofit technology for biomass boilers and associated equipment; 2) seeing how other mill operations solve their biomass boiler area problems; and 3) receiving information and solutions to their mill specific problems.