Firstly, we have learnt about Chapter 1-Balances on Non-reactive Process. We have done a lot of revision about open and close system as well as energy balance equation which we had learnt about that in PCP I. Besides that, we also have done revision about steam table, how to use it and etc. The effect of temperature and pressure on enthalpy and internal energy value also have been teach by Dr.Aznizam which is temperature will significantly influence the value of enthalpy and internal energy. Then, I had learnt about reference state, when to use it and also how to use it. After doing a lot of exercises then I knew how to use it even I’m still confused. By doing many quizzes, I acknowledge that the reference state is really important in energy balance in order to do calculation.
I also have learnt about heat capacities estimation by hard way and also easy way which is just by looking at Table B8. Both ways have been told to me however I’m still get confused sometimes. In addition, I also had learnt about how to draw hypothetical process path and this is one of important part since it required us to draw it during test or exam. By method that have been teached by Dr, I was able to draw it properly. For energy balance calculation, there are some procedures that we need to follow :
a) Basis
b) Mass/Mole balance
c) Reference State : Substance(phase, temperature,pressure)
d) Preparation of inlet-outlet enthalpy table
e) Determination of Enthalpy, from Table B5,B6,B7,B8 or using Heat capacity equation given in Table B2.
f) Calculation of Enthalpy: Hypothetical Process Path must be sketched for phase changes or multiphase except for water or steam.
g) Calculation Heat, Q = nH (out) - nH(in), unit kJ/s (kW)-Inlet-Outlet Enthalpy Table must be refered for convenience.
h) Sometime, from Q (given in question or adiabatic condition), the unknown mass or mole flowrate can aslo be calculated.
i) Box for final Numerical Answer
I also have learnt about energy balance on single phase which is we must know about mass balance, reference state and inlet-outlet enthalpy table, steam table(Tables B5,B6,B7) and Table B8. Besides that, we also learnt about hot to emphasize heat capacity on Table 2(hard way) and Table B8(easy way). The estimation of Latent Heat as well as Delta Hv which can be determined by using Trouton's Rule. The estimation of Heat Capacity of Liquid and Solid can be determined by using Kopp's Rule. The heat capacity of atomic as we know is available in Table 10. After that, we had learnt about energy balances on Phase Change which required for us to construct hypothetical process path in order to calculate enthalpy.
The step of calculations are as follows :
- Basis
- Skecth Unit Process for Mass Balance Calculation
- Reference State : From Stream or Tables given in Ref. Book
- Construct Inlet-outlet enthalpy Table.
- Calculate the value enthapies using Table B1( Latent Heat, Hv; Heat of Fusion, Hm), Table B2 (Heat of Capacities, a+bT+...), Tables B5,B6,B7 and Table B8
- Calculate Q or mass flowrate or Temperature
Before test 1, we do revision on dry bulb temperature (x-axis), absolute humidity (y-axis, moisture content, ha, kg H2O (v)/kg Dry air, relative humidity (hr) and saturation curve (hr=100%), dew point ( using constant pressure line-horizontal and saturation curve), wet bulb temperature (twb), humid volume (kg HA/kg DA), enthalpy (using adiabatic line or wet temperature line) and also enthalpy deviation. We also learnt about adiabatic cooling and energy balance procedure by using chart.
After done learnt that, as usual there are always gifts from our beloved lecturer which are a lot of exercises in order for us to understand the topic. On 11 October 2012, first test was done and what I can said it is really worse for me. I cannot answered the questions in the test and I really disappointed with my result but I know that it is my fault because do not pay attention.