Keeping Coal Clean

This article details the background and construction of a coal storage circular dome for Indonesia’s largest fertilizer producer, PT Pupuk Kalimantan Timur (Pupuk-Kaltim). Geometrica was selected based on the company's ability to meet Pupuk-Kaltim's very specific logistical and environmental needs.

Indonesian Fertilizer Producer Combines Coal with Environmental Responsibility

After carefully considering the fluctuations of the natural-gas market in recent years, PT Pupuk Kalimantan Timur (Pupuk-Kaltim), Indonesia’s largest fertilizer producer, in Bontang, East Kalimantan, launched a project to diversify its fuel with a coal boiler in 2009. In addition to adhering to government policies that encourage the use of coal as a substitute for natural gas, Pupuk-Kaltim executives noted substantial economic benefits.
 
One possible problem, of course, could be environmental impact. Addressing that, Pupuk-Kaltim chose to use only clean-coal technologies, including a circulating fluidized-bed boiler, a Geometrica coal-storage dome and a continuous barge unloader. These technologies had earned recognition for their successful use at the JEA Northside power plant in Jacksonville, Florida, and help keep the environment around the facility pristine. This article discusses the coal-storage dome and its construction.

Specifications Via the Internet

After initial research on dome storage for coal, Mr. Supriono, a mechanical engineer with Pupuk-Kaltim, made the initial contact with Geometrica in 2009. The dome was to be supported by a 10-meter-high, reinforced-concrete, perimeter-ring wall and would cover 40,000 tons of coal, plus a coal stacker and a portal reclaimer. Within a few days, Cecilio Zalba, Geometrica’s sales manager, emailed Mr. Supriono a proposal with preliminary drawings and a guide specification for an 80m-diameter, circular, galvanized-steel dome with aluminum cladding.
 
With that, plus input from possible alternate suppliers, Pupuk-Kaltim wrote a functional specification for the dome. The specification allowed the consideration of different dome-construction technologies, including concrete, aluminum and steel. The dome not only had to resist the specified environmental loads, withstand corrosive attack from the humid Kalimantan environment and help control explosion hazards, but also use technology that permitted fast construction by local crews and without special equipment.

Supplier Selection

After carefully evaluating the various technologies and bids, the project builder, PT Inti Karya Persada Technics (IKPT), selected Geometrica as the dome supplier. “The contractor also received bids from manufacturers of concrete domes and aluminum domes,” said Zalba. “But the Geometrica solution offered more than 25 percent savings.” IKPT and Pupuk-Kaltim chose Geometrica, which set to work on construction drawings.

“This project was very similar to domed bulk-storage facilities we have built worldwide,” said Jorge Parada, Geometrica's site consultant. “Our galvanized-steel dome technology has proved itself in many environments and applications. This one, along the coast of Indonesia in a tropical rainforest, is another great example.” The galvanized-steel dome structure is clad with aluminum sheeting, combining the strength of steel with the corrosion resistance of aluminum. It also meets National Fire Protection Association guidelines for control of confined dust.

Construction in Just Four Months

Construction of the dome and stacker/reclaimer began simultaneously in June 2011. Assembly began at the top of the concrete wall and progressed toward the apex. The assembly, by 20 workers, assisted by two Geometrica consultants, took two months. The aluminum cladding was complete after another two months.By early 2011, the design had been approved in Indonesia, and Geometrica had manufactured the components for the dome at its plant in Monterrey, Mexico. Geometrica labeled, pre-sorted, and packaged the components in the order required for assembly. Crates of these materials were then loaded into containers for shipment to the Port of Jakarta, Indonesia. From there, IKPT transported the containers to the job site in Tanjung Harapan.

"Experienced Geometrica technical-support staff came to Bontang to train our local laborers and supervise their work," said Ahmad Mardiani, Pupuk-Kaltim construction manager. "Because of their contributions and cooperation, our local laborers were successful and proceeeded without delays."

A Satisfied New Customer and a "Green" Success

“Geometrica met all of our expectations for this project, and we are pleased with the operation of the storage facility,” Mardiani continued. "We made our first coal drop into the new storage facility on May 21, 2012. The dome protects the coal from rain and protects the environment from coal dust."

Today, Pupuk-Kaltim’s coal-boiler project is humming along, producing the steam required to help the company deliver its annual 3 million tons of urea to its customers in Indonesia and beyond. As Indonesia’s largest fertilizer producer, Pupuk-Kaltim has won numerous awards for its green practices and outstanding engineering. And the shiny new Geometrica dome at Bontang keeps the coal, and the company's track record, spotless.

For more information about storage of coal under Geometrica domes, see Geodesic Domes for Storing Coal.  If you have a coal stockpile that requires a cover, please send us your information using this inquiry form.