1 reply to this topic

[deltaChe]

Dear Sir

I attached a vacuum drip leg & cooling water consumption calculation spreadsheet. Could you please give me some comment ? Thank you very much.

Attached Files

•  vacuum condenser.xls   33KB   42 downloads

[deltaChe]

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 requried 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.

Edited by steven7788, 16 November 2011 - 08:23 AM.