To determine the surface area required for the heat exchanger, we'll first need to calculate the heat duty Q required to heat the ethanol from 20C to 80C. We can do this using the equation:Q = m * Cp * Twhere:- Q is the heat duty W - m is the mass flow rate of ethanol kg/s - Cp is the specific heat capacity of ethanol J/kgK - T is the temperature change of ethanol K The specific heat capacity of ethanol is approximately 2.44 kJ/kgK. To find the mass flow rate of ethanol, we need to convert the volumetric flow rate 200 L/hr to mass flow rate using the density of ethanol , which is approximately 789 kg/m.m = 200 L/hr * 1 m/1000 L * 789 kg/m * 1 hr/3600 s = 0.0437 kg/sNow we can calculate the heat duty:Q = 0.0437 kg/s * 2440 J/kgK * 80C - 20C Q = 0.0437 * 2440 * 60Q = 6394.8 WNext, we'll use the heat transfer coefficient U and the log mean temperature difference LMTD to determine the required surface area A for the heat exchanger. The LMTD can be calculated using the equation:LMTD = T1 - T2 / ln T1/T2 where:- T1 is the temperature difference between the hot and cold fluids at one end of the heat exchanger K - T2 is the temperature difference between the hot and cold fluids at the other end of the heat exchanger K In this case, T1 = 90C - 20C = 70 K and T2 = 90C - 80C = 10 K. Thus, the LMTD is:LMTD = 70 K - 10 K / ln 70/10 LMTD 37.1 KNow we can determine the required surface area using the equation:A = Q / U * LMTD where:- A is the required surface area m - U is the heat transfer coefficient 1000 W/mK A = 6394.8 W / 1000 W/mK * 37.1 K A 0.172 mTherefore, the required surface area for the heat exchanger to achieve the desired heating of ethanol is approximately 0.172 m.