Evaluation of Operating Parameters Affecting the Performance of Combined Electrolysis and Catalytic Exchange Units

An experimental set up has been designed, fabricated, installed and operated for evaluation the effect of different operating parameters such as temperature (T), hydrogen gas flow rate (G), water flow rate (L) and molar flow ratio (L/G) of feed water to hydrogen gas on the exchange performance of deuterium between water and hydrogen gas in a packed liquid phase catalytic exchange (LPCE) column. The temperature ranged between 298 to 333 K, hydrogen flow rate from 9 to 10.5 mol/m²/s, water flow rate from 8.55 to 10.45 mol/m²/s and molar flow ratio (L/G) from 0.9 to 1.1. A mathematical model has been derived to calculate the height of the LPCE column and evaluate its performance by calculating the number of transfer units (N.T.Us), the height of transfer unit (H.T.U) as well as the deuterium extraction efficiency from gas phase (η) at steady state conditions. The model was utilized also to determine the concentration profile of deuterium in both water and hydrogen gas as the column was divided into N equal segments and the relevant differential equations were solved using MATALAB software.The results showed that the deuterium extraction efficiency (η) is increased by the increase of the water flow rate and accordingly by the decrease of the hydrogen gas flow rate taking into account the flooding characteristics of the packed LPCE column. Also, it was found that the efficiency was increased by the increase of the temperature taking into account the interactions between the other controlling factors. Results revealed that the best deuterium extraction efficiency from hydrogen gas to the water was obtained at maximum number of transfer units of 4.47, operating temperature of 333 K, molar flow ratio (L/G) of 1.1, hydrogen flow rate of 9.5 mol/m²/s and water flow rate of 10.45 mol/m²/s