Cement US EPA ARCHIVE DOCUMENT

CementPROFILE The cement sectorcomprises 114plants in 37 states that produce portland cement,which is used as a binding agent in virtually allconcrete. Concrete, in turn, is used in a widevariety of construction projects and applications.In 2004, California, Texas, Pennsylvania,Michigan, Missouri, and Alabama were the sixleading cement-producing states, accounting forapproximately one-half of U.S. production.54KEY ENVIRONMENTAL OPPORTUNITIESSector At-a-GlanceNumber of Facilities:Value of Shipments:Number of Employees:1141 8 billion217,5003TRENDS Buoyed by a strong residentialconstruction market, the U.S. cement industryhas grown in recent years. Higher prices forother construction materials such as steel andlumber also contributed to greater reliance oncement and, therefore, increased the demandfor cement. Between 2003 and 2004, U.S. cement consumptionincreased by nearly 7% to a record 115 million metrictons. Forecasters expected a 5% increase inconsumption in 2005.6For the cement sector, the greatest opportunitiesfor environmental improvement are in increasingenergy efficiency, reducing air emissions, andmanaging and minimizing toxics and waste.The cement sector voluntarily tracks itsenvironmental performance. In recent years,the Portland Cement Association (PCA) hasexpanded its data collection efforts to obtaininformation on environmental indicators such asair emissions, implementation of environmentalmanagement systems, and handling of cementkiln dust (CKD). PCA reported on these resultsand other issues in its inaugural Report onSustainable Manufacturing in 2005.102 0 0 617 Most of the U.S. demand for cement in 2004 was metby domestic production. Operating at maximumcapacity, U.S. facilities produced 95 million metrictons of cement (including portland and masonrycement), an increase of 2% over 2003.7 To meet increasing demand, U.S. cementmanufacturers have announced plans to increaseproduction capacity by 15% (nearly 15 million tons)by 2010.8In addition, the effort to rebuild New Orleansand the Gulf Coast area after Hurricanes Katrinaand Rita, which struck the region in Augustand September of 2005, is expected to increasedemand for cement over the next four to fiveyears.9

is composed of four elements – calcium, silica,aluminum, and iron – which are commonlyfound in limestone, clay, and sand. Cementmanufacturing requires the thermochemicalprocessing (i.e., pyroprocessing) of substantialquantities of these raw materials in huge kilns atvery high and sustained temperatures to producean intermediate product called clinker. Cementkilns use an average of nearly 5 million Btus perton of clinker.11 Clinker is then ground up with asmall quantity of gypsum to create portlandcement.As illustrated in the Distribution of Cement EnergyConsumption pie chart, cement manufacturingprocesses are fueled by coal and petroleum coke,electricity, wastes, and natural gas.In 2004, the industry derived 60% of its energyfrom coal. Another 16% of the sector’s energywas from petroleum coke, 5% from solid andliquid wastes, and the balance from natural gas,fuel oils, and used tires.12As shown in the Energy Consumption bar chart,the cement sector consumed 422 trillion Btusof energy in 2004,13 which represented almost2% of total energy consumption by U.S.manufacturing that year.14 When normalizedfor production, the sector’s 2004 energyconsumption was 7% lower than in 2001.The following case study illustrates measurestaken at one cement plant to save energy andreduce accompanying emissions.California Portland Cement Company worked with EPA’sENERGY STAR program to develop a formal corporateenergy management program and an energy managementteam at its Colton, CA, plant. The energy savings measuresidentified and implemented at the Colton plant includedimprovements in the manufacturing process, equipmentupgrades or replacement, and new policies for equipmentprocurement. Through these efforts, the plant has significantlyreduced its energy use and accompanying emissions.Between 2003 and 2004, the Colton plant reduced its energyconsumption per unit of production by nearly 5%, whichtranslated into more than 800,000 in savings and theprevention of nearly 30,000 metric tons of carbon dioxide(CO2 ) emissions.The California Portland Cement Company’s energymanagement program is designed to achieve continuingimprovements in energy efficiency through the followingactions:Energy Consumptionby the Cement SectorDistribution of CementEnergy ConsumptionCase Study: California Portland CementCompany’s Energy Management Program TheCementINCREASING ENERGY EFFICIENCY Cement450Coal 60%400 Btus (trillion)*350Oil 1%PetroleumNatural Gas 3%Coke 16%Electricity Purchased11%Tires 3%Electricity GeneratedSolid Waste 1%at Plant 1%Liquid Waste 5%Source: USGS, 2004.300 250200150 1005002001200220032004 Year* Normalized by annual clinker production.Source: USGS. Establishing baseline energy use through metering andother reporting methods;Setting goals based on benchmarking and industry bestpractices;Performing audits to identify opportunities for energysavings;Implementing energy savings measures through capitalspending, operations and maintenance practices,purchasing policies, and inventory controls; andMeasuring improvements.1518

CementREDUCING AIR EMISSIONS Cementmanufacturing operations emit criteria airpollutants and greenhouse gases (GHG).Criteria Air Pollutants Three criteria airpollutants are released to the air during cementmanufacturing: nitrogen oxides (NOX), sulfurdioxide (SO2), and particulate matter (PM).The combustion of fuels at high temperaturesin cement kilns results in the release of NOXemissions. EPA’s National Emissions Inventory(NEI) estimates that, in 2002, the sector released214,000 tons of NOX emissions. As shown inthe Nitrogen Oxide and Sulfur Dioxide Emissionsbar chart, between 1996 and 2002 thenormalized quantity of NOX emissions fell by 6%through the use of various process controls. In2002, NOX emissions from the cement sectoraccounted for approximately 1% of total U.S.non-agricultural NOX emissions.16SO2 emissions from cement plants result fromthe combustion of sulfur-bearing compoundsin coal, oil, and petroleum coke, and from theprocessing of pyrite and sulfur in raw materials.To mitigate these emissions, cement plantstypically install air pollution control technologiescalled “scrubbers” to trap such pollutants in theirexhaust gases. In addition, the limestone used toproduce cement has “self-scrubbing” properties,which enable the industry to handle high-sulfurfuels. NEI estimates that, in 2002, the sectorreleased 177,000 tons of SO2 emissions. Asshown in the Nitrogen Oxide and Sulfur DioxideEmissions bar chart, between 1996 and 2002 thenormalized quantity of SO2 emissions decreasedby 9%.17Quarrying operations, the crushing and grindingof raw materials and clinker, and the kiln lineall result in PM emissions during cementmanufacturing. Most of the PM in the exhaustgases from cement plants is removed by fabricfilters (known as “baghouses”) or by electrostaticprecipitation. As described later in this section,this PM (know as CKD) is often reused in thecement manufacturing process. NEI estimatesthat, in 2002, the sector released 31,000 tonsof PM10 emissions and 13,000 tons of PM2.5emissions. As shown in the Particulate MatterEmissions bar chart, between 1996 and 2002 thenormalized quantity of PM10 emissions from thecement sector remained fairly constant, followingmarked improvements begun in the early yearsof implementing the Clean Air Act.18Greenhouse Gases In the cement sector, CO2emissions result from the burning of fossil fuels(predominantly coal) during pyroprocessing andfrom the chemical reactions (calcination) thatconvert limestone into clinker.2 0 0 6Particulate Matter Emissionsfrom the Cement SectorNitrogen Oxide and Sulfur DioxideEmissions from the Cement Sector30200Metric tons (thousands)*Metric tons r1920 2002 data are preliminary.* Normalized by annual clinker production.Sources: U.S. EPA, USGS.20002001Nitrogen OxideSulfur Dioxide 2002199619971998 2002 data are preliminary.* Normalized by annual clinker production.Sources: U.S. EPA, USGS.1999Year2000PM10PM2.520012002 In 2003, fuel combustion accounted for about97% of total CO2 emissions in the U.S. – withmore than 60% of that coming from powerplants and motor vehicles. CO2 emissions fromall industrial processes accounted for about 2.5%of national CO2 emissions. Within that industrialpercentage, iron and steel production accountedfor about 37%, while cement manufacturingcontributed 29%. Although this sector is thesecond largest industrial source of CO2emissions in the U.S., it accounts for less than1% of total U.S. CO2 emissions.19

MANAGING AND MINIMIZING TOXICSCement manufacturing facilities use a varietyof chemicals and report on the release andmanagement of many of those materialsthrough EPA’s Toxics Release Inventory (TRI).In 2003, 102 facilities in the sector reported450 million pounds of chemicals released(including disposal) or otherwise managedthrough treatment, energy recovery, or recycling.Of this quantity, 96% was managed throughenergy recovery, while 3% was disposed orreleased to the environment, as shown in theTRI Waste Management pie chart. Of thosechemicals disposed or released to theenvironment, 22% were disposed and 78%were released into air or water.In 2003, hydrochloric and sulfuric acidsaccounted for 51% of the amount released ordisposed, while ammonia, manganese, and zincaccounted for another 24%. Along with ethylene,benzene, and lead, these chemicals accounted for89% of all pounds reported to TRI as disposed orreleased by the cement sector.22Total TRI Disposal or Other Releasesby the Cement SectorTRI Air and Water Releasesby the Cement Sector14Recycling 1%Air Releases78%9Pounds (millions)*Releases al or Releases, totalSource: U.S. EPA, 2003.987651112Pounds (millions)*EnergyRecovery96%Treatment 1%Water Releases 1%Disposal22%* Normalized by annual clinker production.Sources: U.S. EPA, USGS.199920002001200220031994 1995 1996 1997 1998 1999 2000 2001 2002 2003Toxicity-Weighted Results (billions)*TRI Waste Managementby the Cement SectorAs shown in the Total TRI Disposal or OtherReleases line graph, the annual normalizedquantity of chemicals disposed or released by thecement sector increased by 196% between 1994and 2003. This increase primarily occurred priorto 1998, and reported disposal and releasequantities have remained fairly stable since then.Quantities released to air and water followeda similar trend.CementIn 2003, PCA formalized its commitment toreduce CO2 emissions from the cement sector byjoining Climate VISION, a voluntary programadministered by DOE. PCA committed to a 10%reduction in CO2 emissions per ton of productby 2020 (from a 1990 baseline). The sectorhopes to reach this goal through changes in thecement manufacturing process and in productformulation.20 In addition, four cementcompanies have joined EPA’s Climate Leadersprogram, which helps partners to developlong-term comprehensive climate changestrategies, set corporate-level GHG reductiongoals, and inventory emissions to measureprogress. Partner companies include CaliforniaPortland Cement Company, Holcim (US) Inc.,St. Lawrence Cement, and LaFarge NorthAmerica Inc.21YearAir and Water Releases, onlyPoundsToxicity-Weighted Results* Normalized by annual clinker production.Sources: U.S. EPA, USGS.20