Hot Topic Hour on August 14 was Industrial Boiler and Cement MACT Timing and Compliance Options

The discussion yesterday was concentrated on solution of the hydrocarbons and organic HAPs problems associated with cement kilns. This led to a broader discussion of the catalytic filter as a way to solve the organics plus all the other air pollutants.  The guiding principle of these meetings is to answer questions which are important to owners. Holcim has to either buy an RTO or find an alternative, so that was why the emphasis on the organics.

The lengthy discussion of the catalytic filter was based on the seemingly great potential but failure to be considered to date for any U.S. cement plant or industrial boiler. Tri-Mer confirmed the success on many combustion applications. McIlvaine has observed that there is a big opportunity to extract the heat from the clean hot gas leaving a catalytic filter. Rod Gravely of Tri-Mer confirmed that customers have been taking advantage of this opportunity.

Here are points to ponder relative to hot gas filters:

• Efficiency is demonstrably higher.

• Cost is maybe high just for a new particulate filter but with NO_x and acid gas control the cost is comparatively low.

• The small footprint makes it potentially a big money saver for plants without much space to retrofit three process systems.

• So the big question is, how reliable will the units be in larger coal-fired plants?

• If DSI is used the concern about keeping the elements clean is greater.

• Goyen will make a presentation at the next Hot Gas Filter webinar on the pulse jet valve selection for ceramic filters.

• Mercury is a concern but Albemarle says one of its activated carbon products is very efficient at 500°F. Gravely of Tri-Mer says that is an optimum temperature for the catalytic filter.

• Another option is to follow the catalytic filter with a Gore membrane module

McIlvaine prepared the following presentation which was only given in part.  Added to it are the inputs from the participants and other relevant information which was made available for the discussion

Here was the basis for the discussion:

• Decision time for industrial boilers and cement plants relative to MACT.

• There are some new technology options to discuss.

• Regulatory uncertainty reduced but there are some new developments.

• The webinar was collaborative. A series of questions were discussed.

• The sequence was based on a unique concept which compares the decision process to travel through a maze

• You need the equivalent of a GPS system to negotiate the maze. It could be called The MACT Global Decisions Positioning System^™ (GDPS).

MACT GDPS

GETTING STARTED

McIlvaine has a number of free sites which explain each of the control options. They are displayed at Continuous Analyses.

• Dry Scrubbing - Continuous Analyses
• Mercury Removal - Continuous Analyses
• Hot Gas Filters - Continuous Analyses
• CCR and Effluent - Continuous Analyses
• Wet Calcium FGD - Continuous Analyses

• Another good resource is the Council of Industrial Boiler Owners (CIBO).  They have some valuable summaries of the requirements. All the information on issues is shown at http://www.cibo.org/issues.htm.

• Comparison of Proposed, Final and Reproposed Emission Limits for Existing CISWI Units

• Comparison of December 2012 FINAL to December 2011 Reproposal and FINAL March 2011 BOILER MACT LIMITS and June 2010 PROPOSED BOILER MACT LIMITS

• There have been good presentations in McIlvaine webinars.  Third Time's the Charm? By Mack McGuffey, Troutman Sanders - Hot Topic Hour March 22, 2012M shows that there have been substantial changes in the proposed limits each time the proposed rule has been revised. 

• CEMENT MACT - The Portland Cement Association (PCA) has also been active in analyzing the regulatory impact of the cement rule.  This rule was litigated and  In an April 18, 2014, opinion authored by Judge Kavanaugh, the D.C. Circuit upheld Environmental Protection Agency (EPA) emission standards for Portland cement plants but struck down the rule’s codified affirmative defense for violations that result from malfunctions, at least as applied to civil penalties assessed in citizen suits. http://www.velaw.com/resources/DCCircuitStrikesDownAffirmativeDefenseWhileUpholdingPortlandCementMACTRules.aspx

•  PCA staff have been among the presenters at McIlvaine Cement MACT webinars. These can be found in the Mcilvaine Global Decisions Orchard at 327310 - Cement Manufacturing 水泥生产

•  Trinity Consultants has provided a good summary of the rule at http://www.trinityconsultants.com/Templates/TrinityConsultants/News/Article.aspx?id=2992

STARTING THROUGH THE MAIZE - SHOULD YOU RETIRE THE PLANT?

Plant retirement is the first consideration. Capital investment to meet MACT will be substantial.  An old power plant may only be valued at $500/kW. Expenditures to meet MACT may, in an extreme case, be $400/kW.  So you are nearly doubling your investment. Will it be worthwhile?  Here are some of the factors to be considered. 

  1^st Decision Tree Stop:  Plant Retirement Decision Tree

A study for CIBO showed that the average industrial boiler operator would have to pay as much as a $4/MMbtu premium to have access to natural gas. The capital cost of new gas turbine combined cycle plants is higher than the retrofit options whose capital cost is shown at CIBO Estimated Capital Costs for Air Pollution Control Equipment for Coal-Fired Industrial Boilers

PCA expects only 20 cement plants to retire as a result of the MACT rule. This year cement production is expected to grow by over 6 percent. Production will grow another 6 percent in 2015. So demand will be high. Most plants will opt to consider the capital investment to meet MACT.  Retirement is the initial stop in the maze but will need to be revisited as the cost of the MACT compliance option is further developed. 

CCA made a presentation last week in our MATS webinar on switching to gas but retaining coal- fired capacity.

Converting to Natural Gas for MATs Compliance by R. Gifford Broderick, Combustion Components Associates - Hot Topic Hour August 7, 2014

Giff Broderick addressed the option of converting to natural gas-firing in an existing boiler.

Revision Date: 8/7/2014

Regulatory Developments

• Lots of concern about carbon limits and impact.

• But a Republican congress would push to reverse policies.

• ROW is wavering on coal.

• Japan has approved funding for three major coal plants in energy-thirsty emerging markets.

• §Germany, typically a leader in global climate action, continues to support coal projects.

• New development bank from the BRICS group of emerging markets - Brazil, Russia, India, China and South Africa - is also unlikely to follow strict coal limits when it launches in two years

STOP 2:   PARTICULATE CONTROL

Particulate:  The decision to upgrade to meet MACT has to start with particulate control. The MACT rule allows the operator to either meet a very low PM_2.5 limit or to separately measure toxic metals. Due to the difficulty in measuring toxic metals virtually all plants will opt for the lower particulate limit.

       2^nd Decision Tree Stop:  Particulate Decision

There are proposed regulations in the U.S. dealing with coal combustion residues and effluent water quality.  Dry scrubbers create combustion residues and wet scrubbers create effluent.  So MACT decisions have to take these future standards into consideration.

Many cement plants already have fabric filters. They may need to upgrade to membrane bags to meet MACT.  In the mercury webinar in July, W.L. Gore pointed out that the leakage of activated carbon through the bags was more likely due to seam failure than bag inefficiency.

3^rd Decision Tree Stop:  Solids Regulations and Flyash Salability

Industrial boiler owners are less concerned about flyash sales than the utility owners. However, it can be a consideration.

Cement plants are concerned with Clinker Kiln Dust (CKD) quality

The majority of CKD is recycled back into the cement kiln as raw feed. In addition, new technology has allowed the use of previously landfilled CKD to be used as raw feed stock. Recycling this by-product back into the kiln not only reduces the amount of CKD to be managed outside the kiln, it also reduces the need for limestone and other raw materials, which saves natural resources and helps conserve energy.

Another principal use of CKD is for various types of commercial applications. These applications depend primarily on the chemical and physical characteristics of the CKD. The major parameters that determine CKD characteristics are the raw feed material, type of kiln operation, dust collection systems, and fuel type. Since the properties of CKD can be significantly affected by the design, operation and materials used in a cement kiln, the chemical and physical characteristics of CKD must be evaluated on an individual plant basis.

4^th Decision Tree Stop:  NO_x Control Technology

There are a number of options for industrial boiler and cement plant owners. The advantages and disadvantages of each are:

HCl - There is a requirement in MACT to reduce HCl. EPA says much of the benefit of MACT is the SO₂ reduction which will coincidently take place with HCl capture.

One new technology not yet on the website is HClear

HClear™ – HCl Abatement Programs

• Stable liquid product
• Low capital investment
• Full service operation
• No impact on flyash
• No interference with mercury control programs
• Selective towards HCl reduction
• Over 20 years of chemical injection experience

The Utility MATS and Boiler MACT Rules have outlet emission requirements that will likely require HCl control. HClear is an alternative to conventional DSI, and can reduce potential PM issues while providing a solution for chloride emissions.

Fuel Tech’s HClear™ program is a complete operating program, supported by Fuel Tech’s highly trained engineers and technicians and designed using their extensive computational fluid dynamics (CFD) modeling and process experience. The HClear system injects a liquid for HCl abatement, and requires no capital investment. The HClear program relies on the injection of a stable aqueous solution into gas streams to reduce gaseous HCl emissions.

HCl emissions must often be reduced from environments with high concentrations of SO₂. Most dry sorbents concurrently react in the flue gas with SO₂ where typical concentrations are 300 to 3,000 ppmv, and also with HCl where typical concentrations are 1 to 100 ppmv. Typical DSI sorbents are not selective in terms of reactivity, which can result in lower HCl removal efficiencies or higher injection rates.

The HClear technology is selective for HCl, resulting in high HCl removal efficiencies, low chemical injection doses, and no impact on particulate loading. Additionally, HClear has no impact on flyash chemistry or pH. Consequently, injection of the HClear program does not increase the leachability of toxic metals from flyash. HClear is also a mild mercury oxidant and does not impact the performance of powdered activated carbon injection for mercury control.

5^th Decision Tree Stop:  Select FGD Type and Reagent

One McIlvaine website covers the wet option - Wet Calcium FGD - Continuous Analyses

GEA has sold several wet scrubbers to cement plants.

Another McIlvaine website covers DSI, spray driers, and circulating dry scrubbers -  Dry Scrubbing - Continuous Analyses

We have posted a new presentation by NatronX. This includes the following performance curves:

Hot gas filtration for all MACT requirements - See McIlvaine Website -  Hot Gas Filters - Continuous Analyses

6^th Decision Tree Stop - Air Toxics

Three air toxics addressed in MACT are mercury, HCl, and toxic metals. The HCl reduction is tied into the FGD.  The toxic metals will be removed by the particulate collector. So that leaves mercury as the remaining contaminant to address.  McIlvaine has covered all the options for mercury reduction at  Mercury Removal - Continuous Analyses

There have been some new developments.  W. L. Gore has successfully piloted their sorbent polymer composite on cement kilns. It follows the baghouse and cooling system and functions at about 220°F. Non carbon bentonite and kaolin-based sorbents are are also providing competition to activated carbon.

Holcim is debating between RTO and SCR for Organics Removal

Enviros pushing for SCR rather than RTO at Holcim

Holcim Cement is requesting a permit amendment to add a new piece of pollution control equipment to its Midlothian cement plant. Holcim's permit request is being prompted by a problem complying with new federal regulations limiting a kind of pollution called Total Hydrocarbons, or THCs. These are also sometimes referred to as "Volatile Organic Compounds." Think Benzene, and other kinds of hazardous flammable gases. In its permit application Holcim says it needs to add new controls to reduce THC to levels and come under the new federal standard. Fair enough. The company then says that it's still trying to decide between two different types of controls and will make up its mind after getting the permit and seeing how well its choice works out on one of its two separate giant kilns.

The two technologies Holcim is considering installing in Midlothian are:

1) A Regenerative Thermal Oxidizer, or RTO, and 2) A Selective Catalytic Reduction unit, or SCR. RTOs are already installed on American cement plants, including TXI's Midlothian kiln just a few miles from Holcim. Up to now full-scale commercial SCR units have only been installed on European cement plants because SCR is more expensive to build and maintain than most cement plant control devices.

The public comment period for telling the state whether to accept or reject Holcim's permit application ended July 11th at 5 pm. So environmentalists have been lobbying for SCR but it is unclear how they think SCR will reduce THC.

THC is a function of quantity in the limestone and that added by the fuel.

Activated Carbon is touted to remove mercury and THC and organic HAPS.  Albemarle says that caution must be used in relying on activated carbon.  It is very effective on some organics and is temperature dependent.  It is not good for methane. 

TriMer says that Organic HAPS are also destroyed by the embedded catalyst.  Good removal on the primary Cement O-HAPs occurs at temperatures over 400˚F, with excellent results on all Cement O-HAPS approaching 500˚F. Dioxins are also destroyed by the filters, typically with 95 percent efficiency or better at temperatures up to 500˚F.

The U.S. is leading the way  for Cement and Industrial Plants around the World

Heidelberg Cement

In addition to addressing the issues of dust and noise, Heidelberg Cement also faces a major challenge in terms of air pollutant emissions in the cement business line. Whereas dust and noise are emitted from different points in the production process, nitrogen oxides, sulfur oxides, heavy metals, dioxins and furans are only emitted from kiln facilities. These pollutants are regularly checked and measured. 

In 2011 and 2012 they were able to further reduce the dust emissions at a number of their sites in Europe. Moreover,

• By introducing European standard technology in Tanzania, they reduced dust emissions there from 100 mg/Nm³ to less than 10mg/Nm³. In Kazakhstan, the filter installations at their kilns have been modernized to conform to EU standards.
  

• They are continually reducing the emission of air pollutants by means of state-of-the-art filtering technologies, innovative procedures and process-integrated environmental protection measures. This in turn enables them to substantially reduce the impact of their operations on people and the natural environment.
  

• At two plants located in Romania and the USA they have reduced the emission of nitrogen oxides by installing SNCR units. In Germany they have invested in measures that optimize the effectiveness of existing SNCR units. Group-wide SO₂ emissions have gone down by 18.2 percent since 2008, NO_x emissions have been reduced by 13.5 percent and dust emissions have decreased by 26.4 percent.

Industrial Boiler and Cement MACT Timing and Compliance Options Webinar Recording - Hot Topic Hour August 14, 2014

The discussion was concentrated on solution of the hydrocarbons and organic HAPs problems associated with cement kilns. This led to a broader discussion of the catalytic filter as a way to solve the organics plus all the other air pollutants

Revision Date:  8/14/2014

Tags:  221112 - Fossil Fuel 化石燃料, Combustion Components Associates, NatronX Technologies, Albemarle, MACT, Mercury

Slides from NatronX which include Trona vs. SBC at Low Temperature by Melissa Patasnick and Joshua Allen, NatronX Technologies - Hot Topic Hour August 14, 2014

Trona information.

Revision Date:  8/14/2014

Tags:  221112 - Fossil Fuel 化石燃料, NatronX Technologies, Trona, MACT, Mercury