In pursuit of zero

Thailand’s Siam Cement Group Public Co. Ltd. (SCG) says it is driven by its “passion for better” and committed to conducting business with good corporate governance and sustainable development principles in mind. To that end, the company’s SCG Cement – Building Materials Co. Ltd. business unit recently installed a shredding line to prepare material for a new system that processes industrial waste into energy that it supplies to the electrical grid.

The shredding equipment for the project was supplied by SSI Shredding Systems, Wilsonville, Oregon, through the company’s distributor in Thailand, TJ Green Energy Co. Ltd.

SCG was established in 1913 by royal degree to produce cement for use in the country’s infrastructure projects. In the century’s time that has since passed, SCG has diversified into three business units: SCG Cement – Building Materials, SCG Chemicals and SCG Packaging.

SCG Cement recently installed the shredding line at its waste-to-energy plant in an industrial estate in Map Ta Phut, Thailand, in the Rayong province. The province is situated in the east of the country on the Gulf of Thailand.

Going to zero

The company says it has streamlined SCG Cement’s production processes to align with the circular economy, increasingly recycling waste materials from other industries for use as fuels and substitutes in manufacturing.

SCG says its circular way and zero-waste-to-landfill policy have led to multiple projects, including this new waste-to- energy plant, which is the first of its kind in Southeast Asia to use Japanese technology for gasification and ash melting.

The idea for the plant stemmed from the company’s use of waste in its cement production, Chanapanpakorn Suradech, project manager at SCG, says. It consumes nonhazardous and hazardous solid industrial waste and some sludge wastes, he adds.

SCG says the plant can process 65,000 tons of industrial waste annually.

“We are aware that industrial waste without proper management can affect the environment and communities a great deal,” says Chana Poomee, vice president for the Cement and Construction Solution Business at SCG. He adds that the company is highlighting the waste-to-energy plant’s “remarkable technologies, standards and residue-free waste disposal” to local communities and target groups.

“We have spent over three years working with the Industrial Estate Authority of Thailand, the Department of Industrial Works and Map Ta Phut community leaders to conduct an environmental health impact assessment and a feasibility study to set up an industrial waste disposal and power plant that complies with law and supports the concept of circular economy,” Poomee told The Nation, a Thailand newspaper in August of 2019.

Panya Sopasriphan, deputy director for business stakeholder engagement at SCG Cement, told the newspaper, “The plant’s operation is a closed-loop system. It will feature pollution and waste control systems that comply with internationally recognized standards, from reception of industrial waste from entrepreneurs and transport to sorting center for predisposal evaluation and analysis through to the disposal in gasifier and ash-melting furnace. While postcombustion residues such as aluminum, steel and fly ash are recyclable, others that are incombustible can be used as alternative materials for road construction. The power derived from the process can be used for electricity generation, while the water can be treated for reuse.”

The project is in excess of $7 billion.

Down to size

The waste-to-energy plant features one Pri-Max primary reducer, model PR4200S, and two Quad four-shaft shredders, model Q145SD. According to SSI, the primary reducer will be bulk fed with commingled waste materials, producing a “flowable, sortable output” at a rate of up to 15 tons per hour. Output from the four-shaft shredders will be smaller than 50 millimeters, or roughly 2 inches, Suradech says.

Rich Ellis, SSI Asia market sales manager, says, “Our shredder’s hybrid design uses a combination of slow and fast speed characteristics to allow the processing of a wide variety of materials, including high-moisture content and heavy contamination.

“The line also includes the ability to [directly] feed the Quad sizing units,” Ellis adds. “This allows for continual production, even during times of maintenance.”

Suradech says SCG shopped for shredders approximately three months before selecting the SSI models because of their “reliability” and “toughness.”

The installation process took roughly one week, Suradech says, which was followed by a longer period of fine-tuning the shredders with the help of TJ Green Energy.

Material is fed first to the Pri-Max PR4200S, a heavy-duty, low-speed, high-torque primary shredder designed for high-capacity volume reduction of “unshreddable” material, according to SSI. The shredder’s “unique cutter profiles and patented open cutting table design are key to achieving high capacity reduction of virtually any material,” the equipment maker adds.

After being processed by the Pri-Max, the material then passes under a magnet, which removes ferrous metal, before being fed to one of the Quad Q145SD shredders.

While SCG installed two Quad shredders at its Map Ta Phut plant, one serves as a standby unit, Suradech says.

SSI touts its low-speed, high-torque, four-shaft Quad shredder’s ability to perform like a two-shaft shredder when the internal screen is removed or as a sizing shredder when the screen is installed, but SCG opts for screened output most of the time, Suradech says. “We normally use them with [the] screen to get [an] exact product size.”

With the help of its shredders, SCG’s new waste-to-energy plant is ensuring the company realizes its zero-waste goals.

The author is editor of Recycling Today and can be contacted at dtoto@gie.net.