Keeping Solvent

Gage specializes in closed-loop recycling technology that reclaims the solvents used to purge paint lines during color changes. In the past, automakers simply pumped the paint/solvent mixture into a tank with other noxious chemicals and carted them off to the incinerator. Not exactly an efficient or eco-friendly way of doing business. But under the Gage system, the same solvent is used again and again, extending its useful life and eliminating it as a pollutant.

The Reclamation Process

Gage begins the process by collecting the spent paint/solvent mixture in a separate tank, where it is pumped into tanker trucks fitted with mixing equipment before being taken to the company’s Ferndale processing facility. The mixture is sampled and analyzed in an on-site laboratory, and paint solids are removed using a thin-film evaporator. At this point, even though the paint is gone, other contaminants—like water—make the solvent unusable. “That’s where reclaimed solvent becomes a second-class citizen,” says Tim Wing, Gage’s vice-president. To bring it up to first-class status, Gage employs a fractal distillation method (similar to what chemical companies use to produce the solvent in the first place) that removes impurities. However, even though the solvent is pure, the original blend parameters are off. So, Gage again analyzes the solution, adding virgin ingredients as needed to re-balance the mixture. (Each automaker specifies the formulation of the solvent that it uses, so Gage processes each plant’s solvents individually to ensure that Ford gets the Ford blend, GM gets the GM blend, etc.) From there, the resurrected material undergoes quality control checks and is shipped back to the plant from which it came. As for the paint solids, Gage is working on ways to re-use them, but currently they are sold to cement kilns, where they are used as a clean-burning fuel that creates fewer emissions than pulverized coal.

 

Cost Savings

Depending on how expensive the raw materials used in their solvent formulas are, automakers can save money by using Gage’s reclamation process. For example, Ford and DaimlerChrysler use relatively expensive chemicals, so reclamation is cost effective, but GM uses cheaper materials, so processing costs outweigh the benefits. However, Wing says, “The major savings for the automaker is that we are managing and optimizing their waste stream.”

Wing says that the amount of paint solids in the used solvent can range as high as 30-35%. And with automotive paint costing between $50 and $100/gallon, even small percentage reductions in waste can save millions. (DaimlerChrysler estimates that Gage’s solvent management program has saved it $7.3 million since 1999.) It’s a mutually beneficial situation since lower paint solid levels make the solvents easier and cheaper for Gage to process, but the bulk of the savings clearly lie with the OEMs. “Probably for every dime we save they save a dollar,” says Wing. And that’s the sort of math Detroit loves.—KEW