This paper aims at designing a large scale plant for the production of biodiesel using 150,000 ton/yr of waste cooking oil produced from various hotels fast food restaurants and domestic areas in the UAE. The transestrification reaction considered takes place at 60 ^oC, 400 KPa, methanol/oil mole ratio of 6:1, 1wt% KOH and carried in four parallel PFR each having an arrangement similar to shell and tube heat exchanger (1 shell and 2 passes & 200 tubes per pass) with static mixing elements inserted in each tube to achieve enhanced mixing even under laminar flow conditions. A detailed equipment design for the proposed flowsheet used for this process, its economic feasibility and profitability analysis is thoroughly done. The profit from biodiesel production along with glycerol as byproduct is found to be $142,877,092  for a ten year project life.  Using 5% tax rate for UAE, the discounted profitability analysis showed a payback period of 6 years and with a rate of return of 39%.