A two-shell passes and four-tube passes heat exchanger is used for heating a hydrocarbon stream (cp = 2.0 kJ/kg·K) steadily from 20°C to 50°C. A water stream enters the shellside at 80°C and leaves at 40°C. There are 160 thin-walled tubes, each with a diameter of 2.0 cm and length of 1.5 m. The tube-side and shell-side heat transfer coefficients are 1.6 and 2.5 kW/m2·K, respectively. (a) Calculate the rate of heat transfer and the mass rates of water and hydrocarbon streams. (b) With usage, the outlet hydrocarbon-stream temperature was found to decrease by 5°C due to the deposition of solids on the tube surface. Estimate the magnitude of fouling factor.
Latent heat and phase change
A physical process in which a conversion among the basic states or phases of matter, i.e., solid, liquid, and gas takes place under the effect of a certain temperature and pressure is referred to as a phase change. Generally, the phase change of a substance occurs when heat transfer takes place between the substance and its surroundings. Based on the direction in which heat transfer takes place, different types of phase changes can occur.
Triple Point of Water
The branch of physics in which observer deals with temperature related properties is called thermodynamics.
Boiling Point of Water
Everyday examples of boiling is, boiling milk, heating water. One would have observed that when we heat water it goes through various stages and at one point bubbles show in water, and water keeps splashing with bubbles bursting, we in layman terms say that water is boiling.
Freezing Point of Water
In general, the freezing point of water is 0° Celsius, or 32° Fahrenheit. This is the temperature at which water will ordinarily change from its liquid state to its solid state (ice). However, there are certain conditions that can affect the freezing point of water. For example, a liquid may be supercooled or contain impurities so that it does not freeze at the ordinary freezing point.
A two-shell passes and four-tube passes heat exchanger
is used for heating a hydrocarbon stream (cp = 2.0 kJ/kg·K)
steadily from 20°C to 50°C. A water stream enters the shellside
at 80°C and leaves at 40°C. There are 160 thin-walled
tubes, each with a diameter of 2.0 cm and length of 1.5 m.
The tube-side and shell-side
1.6 and 2.5 kW/m2·K, respectively. (a) Calculate the rate of
heat transfer and the mass rates of water and hydrocarbon
streams. (b) With usage, the outlet hydrocarbon-stream temperature
was found to decrease by 5°C due to the deposition
of solids on the tube surface. Estimate the magnitude of
fouling factor.
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