Can CEMEX Reduce Smog-Causing Pollutants by 80%?

June 8, 2007

By Joanne Irwin

Can CEMEX, Lyons reduce smog-causing pollutants by 80%? Two recent reports, one by CEMEX, the other by the Texas Commission on Environmental Quality (TCEQ), suggests that the answer is yes. If CEMEX, Lyons installs new NOx Control technology, and maintains the temperatures and dust control needed to ensure the equipment works effectively, then a significant reduction in nitrogen oxide (NOx), a major contributor to smog and haze, is possible. In fact, the TCEQ report predicts that NOx emissions can be reduced by more than 90% if the appropriate technology is installed and well operated.

In March, 2007, the Environmental Protection Agency (EPA) sent CEMEX, Lyons a Notice of Violation (NOV) charging that the plant failed to install the necessary pollution control equipment required by the Clean Air Act (CAA).

When Congress passed the CAA in 1970, it exempted plants like CEMEX that were already in operation. However, the CAA requires older facilities to install modern pollution control equipment whenever the plant makes significant modifications. The Lyons plant made a series of modifications between 1997 and 2000. According to the EPA NOV, these changes resulted in increased yearly emissions of NOx by 563 tons per year from the baseline measurements taken in 1995 and 1996.

The Lyons cement plant emitted 2,462 tons of NOx in 2006 (the most current records available) according to Colorado Department of Public Health and Environment (CDPHE) records. This is equal to the weight of 492 school buses.

New NOx control technology may be what the Lyons cement plant needs to comply with the Clean Air Act and lessen its impact on people, wildlife and landscape in Boulder County and Rocky Mountain National Park.

According to the 2004 study Nitrogen Deposition: Issues and Effects in Rocky Mountain National Park, “unnatural chemical changes due to excess nitrogen are occurring in lakes and streams on the east side of the park.” If nitrogen deposition continues, lakes and soils will likely become acidic and cease to support sensitive aquatic species. “Long-term effects of these changes may be profound as species shifts occur and ecosystem processes are disrupted,” reported the study.

Vaughn Baker, Superintendent of Rocky Mountain National Park, reported that “measured levels of nitrogen deposition have been increasing at about 2.5% per year over the past two decades.” NOx emissions contribute to nitrogen deposition.

Computer modeling done by Colorado’s Air Pollution Control Division in 2005 estimated that emissions from CEMEX hindered visibility in Rocky Mountain National Park about 13 percent of the time.

Last summer, health standards for smog were exceeded five times in Boulder and once in Rocky Mountain National Park.

A CEMEX report published in 2006 states “The two NOx control technologies that have proven effective by full scale application on cement plants are SNCR and SCR.”

Selective Non-Catalytic Reduction (SNCR)

In Europe, 19 cement plants currently use SNCR. In the U.S., CEMEX has installed SNCR in their Brooksville, Fla., plant, and plans to install it at their Balcones, Texas, plant.

The efficiency of SNCR at different facilities can be quite varied. The CEMEX report states, “The efficiency of SNCR at two north Florida plants [neither owned by CEMEX] was in the range of 80 percent, while other sources report efficiencies which ranged from as low as 20% to above 90%, depending on conditions.” Factors such as temperature, dust and fuel type all affect the efficiency of SNCR.

Both the CEMEX report and the TCEQ report cite two cement plants in Sweden that employ SNCR, and reduced NOx emissions by 80 to 85 %. However, the Texas report also lists the results from 16 other kilns in Europe: NOx reduction rates vary from 10 to 50 %. A study done at a North American plant in 1998 showed NOx reductions of only 10 to 20 %.

Selective Catalytic Reduction (SCR)

According to the TCEQ report, “The SCR process has been used extensively throughout the world to achieve a 90% reduction in NOx emissions from fossil fuel fired boilers [in power plants].” Though differences between cement kilns and power plants present some challenges in applying SCR to the cement industry, the Texas study concluded, “recent successful use of SCR at a German cement plant demonstrates that these and other issues may have been resolved. SCR is, under certain conditions, a technically feasible alternative for significantly reducing NOx emissions from cement kilns.”

In 1998–1999 a pilot study using SCR was successful, and a full-scale SCR system was installed on a cement plant in Solnhofen, Germany. The SCR system has been operating with favorable results since 2001, according to the CEMEX report.

The TCEQ report, which studied the technical and economic feasibility of adding NOx pollution controls to 10 different cement kilns in Midlothian, Texas concluded, “The SCR system is achieving NOx emission reductions far in excess of those achievable using SNCR.” The study, released in July 2006, was initiated to fulfill obligations in the Dallas/Fort Worth Litigation Settlement Agreement.

Cost and Other Considerations

The CEMEX report compared the cost of the two technologies in relation to the unique factors at the Brooksville, Fla. plant. The estimated operating cost of SNCR is 40 to 60 cents per ton of cement material. SCR is $1.55 per ton of cement material. Expressed in terms of dollars per ton of NOx removed, CEMEX estimates the cost of SNCR is in the range of $470-500 per ton, while SCR is a little over $2000 per ton of NOx removed.

Factors such as dust, temperature and fuel type all vary the effectiveness of SNCR and SCR systems. Given the Lyons’ cement plant’s history of temperature and dust violations, CEMEX must continue its efforts to improve the management of dust and kiln temperature at the plant if NOx controls are to work effectively. In 2006, CEMEX was fined $1.5 million for “dust and opacity issues, as well as operating temperatures at the facility which can affect air emissions,” according to Mark Smalley, Communications Director for Colorado’s Air Pollution Control Division.

The CEMEX report states, “it must be recognized that an SNCR system will not always be fully effective. SNCR would not effectively reduce NOx emissions during plant startups or a plant malfunction.” CEMEX, Lyons reported 11 plant malfunctions in 2006, according to Christopher Dann, public information officer for Colorado’s Air Pollution Control Division.

There are many technical factors to consider when selecting which technology would work best at the Lyons plant. To date, CEMEX has not announced plans to research or install either system.

Jeremy Nichols, director of Rocky Mountain Clean Air Action (RMCCA), a non-profit group working to clean up Colorado air, suggests CEMEX invest in SCR. “We want to see them use SCR because it is proven to be the best technology for cleaning air, and improving peoples’ health,” said Nichols. Last February RMCCA announced its plans to file suit in federal court regarding the cement company’s increased air pollution.

CEMEX officials declined to answer most questions regarding NOx Control technologies and increased pollution from the plant, as the Lyons plant is “in the context of pending and proposed legal action against the company.” Susana Duarte, CEMEX Vice President of Communications and Community Relations said, “We are working cooperatively with the EPA, and while we cannot comment on the allegations raised by RMCCA, we are disappointed in the lack of factual support related to its allegations.”

“On the issue of NOx, we are operating in compliance with our permit limits,” added Duarte.

With the weight of the current NOV from the EPA, and the proposed RMCCA lawsuit, it seems likely that CEMEX officials will seriously consider investing in NOx Control technology at the Lyons plant.