Three return steam lines in a chemical processing plant enter a collection tank operating at steady state at 9 bar. Steam enters inlet 1 with flow rate of 1.4 kg/s and quality of 0.9. Steam enters inlet 2 with flow rate of 2 kg/s at 200°C. Steam enters inlet 3 with flow rate of 1.2 kg/s at 95°C. Steam exits the tank at 9 bar. The rate of heat transfer from the collection tank is 40 kW.

Explanation:

Neglecting kinetic and potential energy effects, determine for the steam exiting the tank: (a) the mass flow rate, in kg/s. (b) the temperature, in °C.

The solution is shown in the picture below

Three return steam lines in a chemical processing plant enter a collection tank operating at steady state at 9 bar. Steam enters inlet 1 with flow rate of 1.4 kg/s and quality of 0.9. Steam enters inlet 2 with flow rate of 2 kg/s at 200°C. Steam enters inlet 3 with flow rate of 1.2 kg/s at 95°C. Steam exits the tank at 9 bar. The rate of heat transfer from the collection tank is 40 kW.

Here is the complete part of the question

Neglecting kinetic and potential energy effects.

Determine for the steam exiting the tank.

a) The mass flow rate; in kg/s  

b)  The temperature in degree C

The mass flow rate

The temperature in degree C =

Explanation:

Given that;

At Inlet 1; steam enters with

pressure P₁ = 9 bar

quality x₁ = 0.9

mass m₁ = 1.4 kg/s

At inlet  2;

P₂ = 9 bar

T₂ = 200° C

m₂ = 2.0 kg/s

At inlet 3;

P₃ = 9 bar

T₃ = 95° C

m₃ = 1.2 kg/s

Steam exits with pressure P₄ = 9 bar

Heat transfer = 40 kW (out)

Now, let's first calculate the mass flow rate of the outlet using mass rate balance for the streams.

Replacing 1.4 kg/s for ; 2.0 kg/s for ; 1.2 kg/s for in the above equation;   Then:

= (1.4 + 2.0 + 1.2) kg/s

= 4.6 kg/s

Thus, the mass flow rate in kg/s = 4.6 kg/s

Using the Table A-3  " properties of saturated water - pressure table to obtain below properties at pressure of 9 bar

= 742.56 kJ/kg

= 2030.5 kJ/kg

At section (1) ; the enthalpy can be calculated as:

= 742.6 kJ/kg + ( 0.9 × 2030.5 kJ/kg)

= 742.6 kJ/kg + 1827.45 kJ/kg

= 2570.01 kJ/kg

Using the table A - 4 " properties of super-heated vapor  to obtain below properties at pressure of 9 bar & 200° C

Using the Table A - 4 " properties of saturated water (liquid - vapor ): Temperature Table" to obtain below properties at temperature of 95° C

The formula for the steady flow energy is expressed as:

Using the Table A-3 properties of saturated Water-Pressure Table" to obtain below properties at pressure 9 bar

      So  

Using the table  A - 3 " properties of saturated vapor (liquid - vapor ) : pressure table" to obtain the below properties at pressure = 9 bar

Therefore, The temperature in degree C =

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.