Heat Transfer Analysis of Double Pipe Condenser on the Liquid Smoke Production of Cocoa Pod Husk Using Computational Fluid Dynamics

Cocoa pod husk (CPH) is the waste material generated during cocoa (Theobroma cacao L.) production after removing the beans from the fruit. One utilization of CPH is pyrolysis, which produces charcoal and liquid smoke. The condensation process of liquid smoke occurs in the double pipe condenser. The parameter of temperature is very influential on the yield of liquid smoke production. This study aims to conduct heat transfer analysis on a double pipe heat exchanger as a condenser with CPH material using Computational Fluid Dynamics (CFD). Pyrolysis was carried out with three variations of CPH mass 250, 500, and 1000 gr. The condenser uses counter water flow as a coolant at an input temperature of 25.22-25.54 °C and a debit rate of 2.43 L/h. The experimental results showed the temperature of the pyrolysis reactor ranged from 732.97-822.01 °C, the smoke 72.15-94.06 °C, the liquid smoke 27.91-30.95 °C and the water outlet 29.13-32.84 °C. The yield of charcoal produced is 34.05-41.21%, and the yield of liquid smoke is 21.32-30.85%. Simulation with CFD shows that the temperature distribution in the condenser was close to the actual conditions at an error value of 16.20%. The total heat transfer of the liquid smoke condensation process in the condenser for a mass of 250, 500, and 1000 gr, respectively, were 4.971, 7.95, and 11.863 watts. The best quality results of liquid smoke were obtained at pyrolysis treatment of 250 gr with a pH value of 3.84, total acid 2,04%, phenol value of 0,16%, density 995.55 g/L, and yellow to brown colour.