Lighting the Way to Better Drying Technologies

CARD has explored infrared, direct contact and airborne ultrasonic, dielectrophoresis, and jet nozzle technologies for industrial drying. Why focus now on lasers?

Yagoobi: Energy-intensive industry sectors rely on technologies that are old and inefficient to dry materials. There is a need for new drying technologies that use less energy and run on electricity generated by renewable sources such as wind, solar, or biofuels. Lasers are a good option.

What materials will this research focus on drying?

Yagoobi: This project concentrates on the food as well as pulp and paper industries. That includes everything from potato chips and cookies to packaging products.

What makes laser technology a good option for drying?

Yagoobi: Lasers are powerful, and their energy can be spread out over a large area of moist porous materials without causing burns. Also, retrofitting traditional drying technology on production lines can be expensive. Some drying facilities are as big as a football field. Laser units, however, can be easily tacked onto existing production lines, which means there is no need for extensive retrofitting. 

Another advantage is that lasers do not heat enclosed spaces, right?

Yagoobi: Lasers heat the solids in a mixture so that water in the mixture evaporates. If you use lasers in a commercial oven, the walls of the oven remain cool. That is helpful because much of the heat produced in traditional drying equipment is lost as heat dissipates through openings in a production line, the walls of drying machines, and exhaust. As an example, in the food industry, about 30 percent of energy used to operate drying/baking lines goes to drying/baking the food and the rest is lost. We estimate that with lasers, close to 60 percent of energy would go to drying/baking the food and much less energy would be lost.

Industrial laser manufacturer IPG Photonics is a member of CARD. What role will IPG Photonics play in this research?

Yagoobi: This research developed from a discussion I had with IPG, and we will be using IPG laser technology in our WPI testbed. IPG is a world leader in its industry and a great partner in CARD.

What are the critical challenges in drying that this project will seek to overcome?

Yagoobi: One challenge is to develop technologies that make drying more energy efficient without harming the quality of products and adding substantially to costs. For food drying/baking, the challenge will be to preserve the taste and appearance of the products. In paper and packaging, the challenge is to maintain the tensile strength of the materials. Our partner companies have extensive experience in measuring the quality of their products and customer approval, so we will work with those companies to determine if laser drying could be a successful process for them.

How will CARD partners participate in this project?

Yagoobi: WPI will lead the project. We will develop experimental data and physics-based models. The University of Illinois will focus on optimizing the laser drying process. Other partners will include Reading Bakery Systems, which is a commercial oven producer, and groups such as the Alliance for Pulp and Paper Technology Innovation, the Electric Power Research Institute, and RAPID that will help with life cycle analysis.

What excites you about this project?

Yagoobi: One of the best aspects of this project is that it offers WPI students the opportunity to get involved with CARD and research. Students are learning skills, preparing for careers, and sometimes securing jobs with CARD companies. I’m also excited to be working on a project that will make drying more efficient, because drying is a major producer of carbon emissions. It is expected that greater than 0.06 quads of energy—which is 6×1013 British Thermal Units—per year will be saved with the application of laser technology to drying/baking processes. It is exciting to work on something that will address that problem.