The condenser of a large steam power plant is a heat exchanger in which steam is condensed to liquid water. Assume the c

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The Condenser Of A Large Steam Power Plant Is A Heat Exchanger In Which Steam Is Condensed To Liquid Water Assume The C 1 (147.98 KiB) Viewed 32 times

The condenser of a large steam power plant is a heat exchanger in which steam is condensed to liquid water. Assume the condenser to be a shell-and-Tube heat exchanger consisting of a single shell and 30,000 tubes, each executing two passes. The tubes are of thin wall construction with D = 25 mm, and steam condenses on their outer surface with an associated convection coefficient of h, = 11,000 W/m².K. The heat transfer rate that must be effected by the exchanger is q = 2 x 10°W, and this is accomplished by passing cooling water through the tubes at a rate of 3 x 104 kg/s (the flow rate per tube is therefore 1 kg/s). The water enters at 20°C, while the steam condenses at 50°C. What is the tempera- ture of the cooling water emerging from the condenser? What is the required tube length L per pass? SOLUTION Known: Heat exchanger consisting of single shell and 30,000 tubes with two passes each. Find: 1. Outlet temperature of the cooling water. 2. Tube length per pass to achieve required heat transfer. Schematic: T-50°C WI Tube data - 2 x 10°W N = 30,000 D-0.025 m 1 - 3 x 10 1.-11.000 W/m. L = length/pass 1 kg's 7, -20°C Steam T-50°C Water