Date of Defense
Date of Graduation
Chemical and Paper Engineering
Primient, a leading producer of food and industrial ingredients made from plant-based, renewable sources is the industrial sponsor for this project. The company is currently using Plate & Frame Heat exchangers to heat up a 40% by-weight glycol and water solution that is then used to preheat the incoming ambient air. Glycol is being added to reduce the risks of freezing in the system during the winter season. It is important to highlight that this fact affects the heat transfer properties of the liquid overall. Since air heating is a highly energy-demanding process, an outlet stream of hot water produced by recovering heat from across the plant can be conveniently used as the heating fluid in the heat exchangers to further pre-heat the air, reducing the use of natural gas in the air burners.
Towards optimizing their operations, the Western Michigan University team of Chemical Engineering was tasked with improving the heat recovery system that utilizes the glycol and water loop preheated by transferring heat from the gluten hot water loop. The main goal of the project is to improve the energy efficiency of the flash dryers and reduce operating costs.
After thorough research, the Western Michigan University team determined the optimal flow rate of the glycol loop, evaluated the pump capacity to maximize heat recovery, and examined different economic scenarios to identify the best option for Primient. The team utilized computer aided engineering through Aspen Plus software to test the different potential outcomes. Key findings of the sensitivity analysis performed with Aspen indicated that doubling the area of the coils, increasing the flow rate, and raising the temperature of the hot gluten water will favor the optimization.
An economic analysis that accounted for the savings on natural gas for the heating process, evidenced that the desired MARR (Minimum Acceptable Rate of Return) of 40% was achievable in the requested 10 years. With those specifications, a Net Present Value (NPV) of $278,368.99, a Return on Investment (ROI) of 146%/yr, a Pay-Back-Period (PBP) of 0.85 years (10 months and 5 days), and an Internal Rate of Return (IRR) of 73%/yr were determined. Based on the results of the profitability study, this project could be considered for implementation as it seems to be beneficial for the company.
Louden, Sophia, "Air pre-heat system optimization for flash dryers" (2023). Honors Theses. 3764.
Honors Thesis-Open Access