In the Sejong Technology factory in Gangseo-gu, Busan, massive reactors and heat exchangers were lined up under cranes filling the ceiling. After passing through the welding sparks, a test site for verifying the performance of agitators appeared. Measurements were taken of the rotation axis wobble in a test vessel filled with water, followed by a 'water run' test to simulate actual operating conditions. From design to production, testing, and construction, the entire process of chemical plants is carried out in one place.
Established in 1998, Sejong Technology is a chemical plant EPC (Engineering, Procurement, Construction) specialist company. They have expanded their business areas to include polyester and cosmetic raw material plants, as well as semiconductor material, MLCC material, secondary battery electrolytes and cathode materials, solid state materials, and water electrolysis hydrogen production facilities.
Sejong Technology has identified semiconductor materials, secondary batteries, chemical recycling, and nuclear power as their recent growth areas. Among them, the most prominent field is the chemical recycling of waste PET (Polyethylene Terephthalate). This involves implementing a process in a plant that not only uses recycled PET bottles but also returns PET to its raw material stage.
Currently, the recycling of waste PET mainly involves mechanical recycling (MR), where collected PET bottles are washed, shredded, and used again as raw materials. While this process is relatively simple and cost-effective, repeated recycling can lead to a decrease in properties or discoloration. If impurities, dyes, adhesives, etc., are not completely removed, it can also restrict the production of high-quality products.
Sejong Technology takes a different approach by breaking down PET into raw materials through heat or chemical processes, removing impurities, and re-polymerizing to produce PET again. This method involves breaking down the finished plastic into raw units and returning it to the starting point of a new product.
According to Sejong Technology CEO Ko Young-hyun, chemical recycling involves separating the raw materials that made up PET, purifying them to a high purity level, and using them in the production of new PET.
This technology is akin to 'material regeneration'. Instead of simply changing the form of the product and reusing it, it restores waste products to a level where they can replace existing petrochemical raw materials through chemical processes. Once commercialized, waste PET can return to high-quality PET bottles or fiber raw materials.
This technology can also be applied to other materials. Polyester, widely used in clothing and industrial fibers, has a similar chemical structure to PET. However, recycled polyester fibers are more challenging to separate and purify due to the presence of various dyes, additives, and other materials. Sejong Technology is also researching processes to remove dyes and impurities and recover raw materials from waste polyester fibers.
Preparations for commercialization are also underway. They are preparing for the construction of commercial plants in the Ulsan area with major local companies and aiming to start construction as early as next year.
CEO Ko emphasized, "We are evolving from a company that only manufactures machines to an engineering company that designs the entire process" and stated, "We plan to expand our business into future industries such as semiconductor materials, solid-state batteries, chemical recycling, and nuclear power."