CEMEX' Balcones plant near New Braunfels is nearing completion of an expansion project begun in January 2007 that will double the facility's existing production while reducing emissions. The expansion is being built by both CEMEX and Zachry Construction Corporation of San Antonio.
Zachry has been constructing a new cement line with a planned production capacity of 3,850 short tons per day, and all construction has had to be accomplished without interfering with the operation of the existing production line.
The project included construction of a limestone storage and reclaim facility, a raw mill feed structure, a water cooling tower and air compressor building, a raw mill system, a clinker cooler, a coke/coal mill system, and a cement mill system, all of which were constructed by Zachry, as well as silt fencing installed to protect the environment.
Zachry also remodeled the existing control room and completed two outages in September 2007 and January 2008 to tie new baghouses into the existing line. The control room was updated with systems that will enable CEMEX to operate both production lines from one location. The Zachry team installed a new control panel, flooring, ceiling, and walls, and rewired the control room.
According to Zachry project manager Andy Power and operations manager Dan Pratt, "another challenge has been the small area in which we have to construct the new line. Cement lines are compact in general, and constructing an addition within an existing operation means even tighter quarters. We are fortunate to have a 30-acre laydown area northeast of the plant. When it became full, the overflow materials were placed at the back of the nearby quarry."
A blending silo and loadout was slip formed by CEMEX subcontractor Borton, with mechanical, structural, electrical and instrumentation work in the silo being completed by Zachry. Borton also slip formed a preheater tower, which was built with a reinforced concrete frame with a steel interior. The CCC group completed the foundation work for the tower, and Zachry completed the structural steel work inside the concrete tower frame. As the tower was being slip formed, steel embeds were poured into the structure. As the structural steel work inside the concrete tower frame rose, the preheater equipment was installed at the appropriate height. A 64-ton Favco tower crane supported the tower throughout the process.
Preheater equipment included cyclones and a calciner, which were fabricated offsite by KHD and shipped to the site by truck in pieces as large as the trucks could handle. The pieces were then offloaded in the laydown yard and assembled on site with the aid of two 3900 Manitowoc crawler cranes. KHD also fabricated and supplied the ductwork, and the structural steel was fabricated by Qualico.
The four main bag houses were supplied and erected by Solios Environmental with the aid of two 2500 Kobelco crawler cranes, and the kiln was installed by Philips. Additionally, Zachry expanded the existing limestone storage building by adding a 300-foot-long extension and installing a new reclaimer and conveying system.
A new double track 200-plus car capacity railroad, which required approximately 17,000 linear feet of rail, was laid by CEMEX subcontractor Track Works and completed in April. Dirt and ballast work for the new railroad was completed by Zachry, which required excavation of approximately 480,000 cubic yards of dirt and the addition of approximately 45,000 tons of ballast.
The surface area of the new production line is fairly small, but the structures are quite tall. This project required nine cranes, and precise civil, structural, electrical and mechanical work was especially critical. Additional equipment required included four 75-ton Grove pickers where needed, two 15-ton Galion pickers as needed, and various excavators and haul trucks.
The concrete used on the project was supplied by Ingram Readymix made with CEMEX cement produced on the existing production line at Balcones. Rebar was supplied by Capitol City Steel with structural steel being supplied by Qualico. Gravel and ballast for the railroad were supplied by CEMEX. Zachry Construction supplied pipe from Turner Industries, as well as civil components and bulks for all the crafts. CEMEX supplied all required equipment, which was manufactured by Loeshe, IKN, KHD, and Solios.
Safety was and is the first priority of CEMEX and Zachry Construction. Standard safety procedures are in place at this job site, and with the help of the CEMEX expansion management team, the safety program has a recordable incident rate on site of 0.66 based on 1.8 million work hours completed through April 27.
Because a lot of the work on this project is elevated, management has instituted a 100-percent fall protection (tie off) policy to help keep employees safe. Safety management is headed by a dedicated CEMEX and Zachry safety team whose sole job is to ensure that all safety procedures are being followed and all employees are properly trained and equipped to safely perform their duties. The site has daily safety meetings where the crew completes Safety Task Assignments (STAs), which help employees to recognize all possible hazards associated with a task and then either eliminate those hazards or implement controls for their protection. A site safety meeting is held once a month wherein a "Crew of the Month" is chosen and rewarded based largely on safety performance.
Once the production line is operating, emissions will not increase even though the capacity is being doubled, according to CEMEX management. "This is being accomplished because of CEMEX's willingness to invest in the newest and best technology available. As a result, the Balcones site will be one of the most efficient and productive cement plants in the country, and will be operated in the most responsible and environmentally conscientious manner possible. Specific energy usage will go down, dust emissions will be reduced, and all emission controls will be greatly enhanced."
To increase efficiency, CEMEX replaced the dust collection equipment in the existing kiln line and installed state-of-the-art technology to continue to protect the environment. The old kiln and cooler had an electrostatic precipitator and a gravel bed filter, but were upgraded with new fabric filter dust collectors made by Solios Environmental of Canada.
Additionally, new and improved NOx control technology capable of burning 100-percent pet coke and a modern automation system produced by FLS Automation of Bethlehem, Pa., were installed in the existing kiln. The same technology, which was applied to upgrade the existing production line, is also being installed in the new production line.
A tubular calciner was chosen as the most efficient method to address carbon monoxide reduction. The tubular calciner allows a lengthy retention time and provides thorough mixing capability. Additionally, the inherent cleansing effect of the pre-heater and the inline raw mill are key elements in the reduction of sulfur dioxide emissions.
The expansion had to be completed in a very small area on a very aggressive schedule, all of which required careful organization, planning, scheduling and collaboration by everyone working on the project. Zachry Project Execution Planning Process (also known as "ZPEPP"), Zachry's signature project execution and planning process, provided a framework to help keep all project partners coordinated.
Zachry's Andy Power says, "CEMEX is a preeminent force in the production of cement, concrete and aggregates, and the Zachry team is privileged to serve the company. This environmentally friendly expansion will enable CEMEX to help meet the growing demand for high-quality cement, while meeting CEMEX's priority of conducting its business with respect and care for the environment. We have learned many lessons from this project and hope to have the opportunity to put them into practice on future jobs with CEMEX."
The new production line is expected to be completed and operational at CEMEX Balcones in the summer of 2008.