Subject: Conference call with Portland Cement A ssociation – Startups and Shutdowns

Location: U.S. Environmental Protection Agency, Research Triangle Park, NC

Date: November 2, 2011

Participants:

Portland Cement Association (PCA) Andy O’Hare, PCA Curtis Leslie, Ash Grove Mike Pelan, Lafarge Hector Ybanez, Holcim U.S. Environmental Protection Agency (EPA)

Keith Barnett

Sharon Nizich

Peter Westlin

RTI International Mike Laney

The purpose of the meeting was to discuss kiln and control device opera tions during startup and shutdown periods as they occur in the portland cement industry. The following key points were

discussed:

 Compliance requirements in the current portland cement NESHAP during startup and

shutdown assume a cold startup following a prolonged shutdown typically for major maintenance and/or repairs. This type of st artup would require seve ral days involving the use of gas or oil fuels to br ing the kiln temperature up to an optimum temperature at

which feed materials would be re-introduced. According to industry, cold startups only occur one or two times in a year.

 According to industry, most startups and shut downs are associated with malfunctions or other unexpected, unplanned events. Startups from these events are considered warm startups because the kiln typi cally is not shutdown completely but retains whatever load

is in the kiln at the time of the malfunction or other event and the kiln continues to rotate, usually at a slower rate, and an alternate fuel is fired to ma intain a temperature that will prevent the material in the kiln from coo ling excessively. Comple tely shutting down the kiln (halting rotation and firing) while it reta ins a load of hot raw materials would warp

the kiln.

 Most startup and shutdown practices are safe ty driven. Complete shutdown with a cold start occurs just one or two times a year. The shutdown involves emptying as much of the load from the kiln as possible and bringing the kiln temperature down gradually to avoid damage to the kiln. These periods are used to perform major repairs and maintenance, such as replacing refractory bricks, on the kil n. Workers enter the kiln after it is cooled and use jack hammers to break up any solidifie d load. Cold starts must occur over several days in order to properly cure and seal refractory bricks. During the more common shutdown to address a malfunction, the feed of raw materials to the kiln is suspended. The length of time the feed is suspended varies by kiln type and size. The longer wet kilns, for example, may require a longer shutdown and startup period than the shorter preheater /precalciner kilns. The lengt h of the startu p period will also depend on how the extent to which the k iln was shutdown. While the kiln is in a partial shutdown mode, no feed is being added, but the kiln continues to be kept warm by firing with an alternate fuel such as na tural gas and the kiln rotation is slowed.

 For economic and safety reasons and regardle ss of the type of shutdown, the goal in the industry is to return the kiln to full production as soon as possible.

 Industry practice is to operate control devices anytime the kiln indu ced draft (ID) fan is operated. The ID fan is always on when fuel is being fired in the kiln.

 Air flow through the kiln is lower during startup.

 Kiln ID fans are typically va riable speed, although some ol der kilns use constant speed fans and dampers to control air flow through the kiln.

 A kiln is considered to be operating norma lly when it is producing quality clinker.

 According to the industry, state Title V pe rmits do not strictly define startup and shutdown, but typically leave it up to individu al plants to determine when a startup and

shutdown occurs.

 The startup and shutdown of a kiln is more co mplicated than that of a boiler because of the presence of fuel and feed. A boiler st artup and shutdown must only consider fuel.

 For issues related to testing and monitoring during startup and shutdown, the industry has already provided info rmation to the EPA.