Vacuum drip leg calcuation

[knapee]

Dear Sir

I have a vacuum drip leg calculation and cooling water consumption
attached in this post. Could you please kindly to comment this spreadsheet ?

Thank you very much.

 

[knapee]

Dear Sir

It seems my poor English hinder any help for this forum.

So, I post my question here and put it more clearly,

a vacuum condenser
known Data :
1.Vacuum package production capacity = 1200 tons heavy oil /day
2.steam vapor consumption = 6% of feed
3. cooling water supply temp = 25 C
4. steam vapor & Gas mixture temp = 90 C @ inlet of vacuum condenser
5. Vacuum @ vacuum condenser = 710 mmHg


B = Z_steam * (q - t_2) + G_gas * 0.5 (t_3 - t_4) / (t_2- t_3) ----------------- Eq 1
B: amount of cooling water consumed kg/hr
t_1: temp of cooling water supply 25C in this case
t_2: temp of cooling water discharge 33C in this case
t_3: temp of mixed of steam vapor and gas 90C in this case
t_4: the gas temp at bottom of condenser 25C in this case
q: the enthalpy of steam into the condenser kcal/hr
Z: amount of steam kg/hr
G_gas amount gas kg/hr
0.5 : the heat capacity of gas kcal/kg-C
in Eq1 Z(q-t_2) : the amount of heat required to condensed the steam into vacuum condenser to t_2

But, I don't quite understand this means, as water Cp=1kcal/kg-C
q is latent heat, it seems that total heat required to condensed steam to t_2 water
should be Z * q + Z*1*(100-t2) instead of Z(q-t_2)


The second question is

H = 10.33 * b / 760 + h + 0.5 * M
where
H = height of vacuum drip leg
b = vacuum in the vacuum condenser
h = pressure difference required to be concur as water coming out from the condenser
0.5M = the margin required to be undo the water coming into the vacuum drip pipe as pressure fluctuation

How is this formula derived, vacuum drip leg height H is to prevent the water coming in or gas enter in
and what is the physical meaning behind this?

Thank you so much for your kindly help.

 

[Compositepro]

Your questions are very basic and hidden with a lot unimportant details.

Ask yourself what can (q-t_2) possibly mean? How can you subtract a temperature from a heat. What is two apples minus one orange?

You also give two different definitions of q.

 

[knapee]

Hi

Thank you very much for your kindly reply.
Yes, obviously q-t_2 doesn't make any sense to us,
but I think it simplify from q-m*Cp*delt T cause Cp=1,
and it just copy an example from a famous book.

Please any pro help me out.

Thanks again.