The heat duty of the jacketed vessel of Examples 12.15 and 12.16 can be estimated from the coolant flow rate and temperatures. What is the minimum temperature at which the reactor can operate using the jacket as designed? Does the choice of coolant make sense at this temperature? Propose a better design.

Data from example 12.15 and 12.16

A jacketed, agitated reactor consists of a vertical cylinder 1.5 m diameter, with a hemispherical base and a flat, flanged, top. The jacket is fitted to the cylindrical section only and extends to a height of 1 m. The spacing between the jacket and vessel  walls is 75 mm. The jacket is fitted with a spiral baffle. The pitch between the spirals is 200 mm. The jacket is used to cool the reactor contents. The coolant used is chilled water at 10°C; flow-rate 32,500 kg/h, exit temperature 20°C.  Estimate the heat-transfer coefficient at the outside wall of the reactor and the pressure drop through the jacket.

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The reactor described in Example 12.15 is fitted with a flat blade disc turbine agitator 0.6 m diameter, running at 120rpm. The vessel is baffled and is constructed of stainless steel plate 10 mm thick. The physical properties of the reactor contents are: p = 850kg/m³, μ = 80 mNm ²s, kg = 400 x10³W/m°C, Cp 2.65 kJ/kg °C. Estimate the heat-transfer coefficient at the vessel wall and the overall coefficient in the clean condition.