Abstract
One of the main solutions to climate change is to harness energy from renewable and clean resources. A novel ocean thermal energy conversion (OTEC) system is proposed for the production of methanol; cooling and power is developed and energetically analyzed. In this proposed trigeneration system, a two-stage Rankine cycle that operates on the inherent temperature difference along the depth of the ocean is used for power production, along with an electrolytic cation exchange membrane (ECEM) reactor for carbon dioxide and hydrogen production to feed the methanol production system. The carbon dioxide is sourced from the deep cold seawater, where the concentrations are found to be the highest. The proposed system performance is modeled and simulated on the Aspen Plus, where the performance of the proposed system is assessed under various operating conditions. The results of this study shows that the maximum net power output of the cycle is found to be 51.5 GW, with a fixed rate of district cooling of 69.0 GW. The maximum methanol production rate was found to be 1.36 kg/s at the power input of 51.5 GW. The system is tested under three different operation cases, to fully assess its viability. It should be noted that in all three cases district cooling is included as a product of the system. Case 1: ECEM reactor operates at its current efficiency with fuel production, Case 2: ECEM reactor operates at proton exchange membrane (PEM) efficiency, and Case 3: Only power was produced with no fuel. The maximum overall energy efficiency of the cycle was found to be 8.0, 8.6, and 7.3% for Cases 1, 2, and 3, respectively.
