Page 462 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

428 Applied Process Design for Chemical and Petrochemical Plants

SAFETY VALVE DESIGN OPERATIONAL CHECK SHEET

Date: Job No.: ------
Checked: By:

Vessel or System: --------=------------------�
Process Evaporator
Design Pressure: 75 PSIG
Allowable Pressure for Capacity Relief: 75 + (75+ 10%) =
= 82.5 PSIG
Operating Conditions: Fluid: PDC Mol Wt. 113.5
Oper.
Sp.Gr. 1.16 Temp. -=---------
Latent Heat 125 BTU/Lb. Corrsive No
----
Physical Conditions: Vessel Dia. 5 feet x Length : 6 feet
Insulation: Yes, 2 11
__
Fi re Con tr o 1 Me a-s�u-r_e_s_ : N_o_S_p_r_i_n_k_l_e_r S_y_s- .
======================================================================
Cause of Overpresure Capacity Requiremant, Lb./Hr.

1. Failure Cool water/Elect/Mechanical
2. Reflux and/or Condensing Failure
3. Entrance of a Highly Volatile Fuel
4. Vapor generation, external fire ----2,920---------------
5. Excessive Operating Heat Inputs ---22,500---------------
6. Accumulation of Non-Condensibles
7. Closed Outlets ---22,500 or less-------
8. Failure of Automatic Controls/Instr. ---22,500 or less-------
9. Internal Explosions(Use Rupture Disk)
10.Chemical Reaction/Run-a-Way(" " )
11.Two Phase Flow Conditions
12.Inadvertent opening valve into system
13.Check Valve failure
14.Cooling Fans failure
15.Heat Exchanger Tube rupture/failure
16,Circulating Pump failure

Causes that may occur simutaneously: ------------------------
------ Any of the four considered may occur simultaneously------
Probability of occurence: --Closed outlet with a failure of
automatic control resulting in excessive heat input.----------
Allowance to made:----None------------------------------------
Relief capacity used for sizing valve(s)------22,500 Lb./Hr.--
======================================================================
Auxiliaries Cause of Overpressure Capacity Requirement
1. Exchangers Split tube(s) 1482 Lb.Hr.
Thermal Vaporization
2. Pumps Discharge Restriction
3. Length of Line Thermal Vaporization

Figure 7-14. Safety valve design operational check sheet. Adapted and added to by permission, N. E. Sylvander and D. L. Klatz, Design and
Construction of Pressure Relieving Systems, Univ. of Michigan Press, Ann Arbor (1948). Six items of overpressure list above by this author
and from API Rec. Practice 521 (1982).