Pressure protection manager system & apparatus

• US 5,774,372 A
• Filed: 03/29/1996
• Issued: 06/30/1998
• Est. Priority Date: 03/29/1996
• Status: Expired due to Term

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Pat Berwanger
• Inventors: Berwanger, Pat
• Primary Examiner(s): Voeltz, Emanuel Todd
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US08/624,174
• Time in Patent Office: 823 Days
• Field of Search: 364/551.01, 364/509, 364/510, 364/558, 364/565, 364/431.01, 364/494, 364/495, 364/915, 137/12, 376/215, 376/217, 376/255
• US Class Current: 700/301
• CPC Class Codes: F16K 37/0075 For recording or indicating the functioning of a valve in combination with test equipment
• CPC Class Codes: Y10T 137/0379 By fluid pressure

Abstract

The Pressure Protection Manager comprises an apparatus and method for determining and documenting overpressure protection due to causes of overpressure associated with equipment and pressure relief devices used in industries such as, for example, process plants having process fluids. The apparatus is used in association with a computer system having a memory device, a processing device, and a program in communication with the processing device and memory device program, the processing device performing tasks required by the program and the computer system further having input and output devices, the memory device comprises: a relational database structure, the relational database structure comprising an equipment database, a pressure relief devices database, a linker database communicating with the pressure relief devices database and the equipment database, and a causes of overpressure database communicating with the equipment database.

Claims

1. An apparatus for determining and documenting overpressure protection due to causes of overpressure associated with equipment and pressure relief devices the apparatus comprising:

a computer system comprising a memory device, a processing device, a program in communication with the processing device and memory device, the processing device performing tasks required by the program, the memory device further comprising;

a relational database structure, the relational database structure comprising;

(a) an equipment database,

(b) a pressure relief devices database,

(c) a linker database communicating with the pressure relief devices database and the equipment database, and

(d) a causes of overpressure database communicating with the equipment database.

2. The apparatus of claim 1 wherein the pressure relief devices database communicates with other database devices comprising a pressure relief valves database device, a rupture disks database device, a tank vents database device and an other devices database device.

3. The apparatus claim 1 further comprising an identification causes of overpressure database for identifying potential causes of overpressure for each piece of equipment and providing identified data for use in other database wherein the relational database structure comprises:

(a) the equipment database device linked to the causes of overpressure database device and further linked to linker database device for quantifying the required relief rate for each identified cause of overpressure

(b) the equipment database linked to the linker database, and the linker database linked to the pressure relief database for quantifying actual relief capacity for the actual relief devices,

(c) the pressure relief devices database, the pressure relief valves database, the rupture disks database, the tank vents database and the other devices database communicating for the purpose of quantifying required relief device size for the required relief rates.

4. The apparatus of claim 1 wherein the processing device further comprises means for instructing the user to evaluate and quantify the adequacy of the pressure relief device.

5. The apparatus of claim 1 wherein the processing device further comprises means for quantifying and evaluating global scenarios and release from individual pressure relief devices as associated with discharge piping and relief headers.

6. A method for determining and documenting overpressure protection due to causes of overpressure associated with equipment and pressure relief devices, the method comprising the steps of:

(1) identifying all potential causes of overpressure for each piece of equipment,

(2) quantifying the required relief rate for each identified cause of overpressure,

(3) quantifying and evaluating adequacy of pressure relief device, and

(4) identifying and evaluating global scenarios and release from individual pressure relief devices as associated with discharge piping and relief headers.

7. The method of claim 6 wherein the the step of quantifying and evaluating adequacy of pressure relief device further comprises the steps of:

(a) quantifying actual relief capacity for the actual relief devices,

(b) quantifying required relief device size for the required relief rates,

(c) evaluating and quantifying the adequacy of pressure relief device.

8. The method of claim 6 wherein the pressure relief device is a pressure safety valve.

9. The method of claim 6 wherein the pressure relief device is a rupture disk.

10. The method of claim 6 wherein the pressure relief device is a vent.

11. The method of claim 6 wherein the pressure relief device is any other device functioning as a pressure relief device.

12. The method of claim 6 wherein the step of identifying all potential causes of overpressure comprises the steps of:

(a) defining the causes of overpressure,

(b) defining the associated relief devices, and

(c) defining the relevant data needs to determine the required relief rates.

13. The method of claim 6 wherein each relief device is defined comprises the steps of:

(a) determining whether the relief device is a pressure safety valve, and if so, the pressure safety valve is defined comprising the steps of;

(1) defining the device specifications for the pressure safety valve, if any,

(2) defining the testing requirements for the pressure safety valve, if any,

(3) defining the material selection requirements for the pressure safety valve, if any,

(4) defining supplier information for the pressure safety valve, if any, and

(5) defining the inlet and outlet connections and piping data for the pressure safety valve, if any,

(b) determining whether the relief device is a rupture disk, and if so, the rupture disk is defined comprising the steps of;

(1) defining the device specifications for the rupture disk, if any,

(2) defining the testing requirements for the rupture disk, if any,

(3) defining the material selection requirements for the rupture disk, if any,

(4) defining supplier information for the rupture disk, if any, and

(5) defining the inlet and outlet connections and piping data for the rupture disk, if any,

(c) determining whether the relief device is a vent, and if so, the vent is defined comprising the steps of;

(1) defining the device specifications for the vent, if any,

(2) defining the testing requirements for the vent, if any,

(3) defining the material selection requirements for the vent, if any,

(4) defining supplier information for the vent, if any, and

(5) defining the inlet and outlet connections and piping data for the vent, if any,

(d) determining whether the relief device is another device, and if so, the other relief device is defined comprising the steps of;

(1) defining the device specifications for the other relief device, if any,

(2) defining the testing requirements for the other relief device, if any,

(3) defining the material selection requirements for the other relief device, if any,

(4) defining supplier information for the other relief device, if any, and

(5) defining the inlet and outlet connections and piping data for the other relief device, if any.

14. The method of claim 6 wherein the step of quantifying the required relief rate for each identified cause of overpressure comprises the step of defining the physical properties of the process fluids contained in the equipment including fluid type, physical properties at relief pressure, heat of vaporization, vapor molecular weight, vapor density and liquid density.

15. A method for determining and documenting overpressure protection comprising the steps of:

(a) defining each piece of process plant equipment in an equipment record in an equipment database,

(b) defining one or more causes of overpressure for each piece of equipment in a causes record in an identification of causes of overpressure database and linking the causes records to the corresponding equipment record in the equipment database,

(c) defining one or more relief devices in a device record in a pressure relief devices database,

(d) quantifying required relief device for each piece of equipment for each cause of overpressure in the causes of overpressure database,

(e) linking each equipment record in the equipment database to its respective device records in the pressure relief devices database,

(f) sizing each relief device for applicable relief scenarios, and

(g) evaluating entire relief system including pressure relief devices and discharge piping.

17. The method of claim 15 wherein the step of evaluating pressure relief device requirements comprises the steps of:

(a) evaluating whether the pressure relief device requires non-standard sizing, and if so, using the manufacturer'"'"'s equations, and if not, using data for required relief rate,

(b) quantifying the actual relief rate capacity and the required pressure relief device size, and

(c) quantifying pressure drop across pressure relief device, if required.

21. The method of claim 17 wherein the step of determining if the fluid is a stream comprises the steps of:

(a) determining that the fluid is a steam,

(b) entering the steam information,

(c) defining required flow rate and cause of overpressure units for pressure relief device being sized,

(d) determining nonstandard sizing requirements,

(e) determining if relief valve goes to flare, and

(f) verifying adequacy of existing pressure relief devices.

16. A method for determining and documenting overpressure protection due to causes of overpressure associated with equipment and pressure relief devices comprising the steps of:

(a) selecting a piece of equipment associated with the causes of overpressure,

(b) defining equipment information,

(c) identifying applicable causes of overpressure for a particular piece of equipment,

(d) quantifying a required relief rate,

(e) choosing the appropriate sizing equations for particular piece of equipment,

(f) entering physical property data, as needed,

(g) calculating required relief rate,

(h) selecting relief devices,

(i) selecting a piece of equipment,

(j) evaluating pressure relief device requirements,

(k) identifying global scenarios,

(l) quantifying global scenarios,

(m) calculating back pressure and velocity for global scenarios, and

(n) validating device performance.

18. A method for determining and documenting overpressure protection due to causes of overpressure associated with equipment and pressure relief devices comprising the steps of:

(a) identifying all potential causes of overpressure for each piece of equipment,

(b) quantifying a required relief rate for each identified cause of overpressure,

(c) defining operating pressure and set pressure associated with relief device,

(d) defining constant and built-up back pressure,

(e) defining predetermined blowdown,

(f) selecting discharge destination and predesignated design code,

(g) selecting allowable overpressure for rate that the relief device is being sized,

(h) determining if the fluid is a stream,

(i) defining required flow rate and cause of overpressure units for pressure relief device being sized,

(j) determining nonstandard sizing requirements,

(k) determining if pressure relief devices goes to flare, and

(l) verifying adequacy of existing pressure relief devices.

19. The method of claim 18 wherein the step of determining nonstandard sizing requirements comprises the steps of:

(a) evaluating that nonstandard sizing is not required, and

(b) using manufacturer'"'"'s equations concerning orifice area and actual flow.

20. The method of claim 18 wherein the step of determining nonstandard sizing requirements comprises the steps of:

(a) evaluating that nonstandard sizing is required,

(b) if fluid is two-phase or flashing, using Design Institute for Emergency Release Systems or American Petroleum Institute method of calculating flow, and thereafter quantifying actual capacity and required pressure relief device size,

(c) if fluid is not two-phase or flashing, quantifying actual capacity and required prd size,

(d) entering actual orifice area or corresponding size,

(e) entering physical property data, if needed,

(f) calculating required pressure relief device size,

(g) calculating actual capacity of pressure relief device,

(h) if a pressure drop across valve exists, implement the steps,

(1) defining inlet and outlet information,

(2) calculating pressure drop at inlet and outlet,

(i) if relief valve and goes to flare, implement the step of defining the fluid characteristics, and

(j) verifying adequacy of existing pressure relief devices.

22. The method of claim 18 wherein the step of determining if the fluid is steam comprises the steps of:

(a) determining that the fluid is not steam,

(b) entering the description of the fluid,

(c) entering the actual mass percent vapor,

(d) if the fluid is 100% liquid, implementing the following steps,

(1) entering liquid gravity, liquid viscosity, temperature and vapor pressure at relief pressure,

(2) defining required flow rate and cause of overpressure units for pressure relief device being sized,

(3) determining nonstandard sizing requirements,

(4) determining if relief valve goes to flare, and

(5) verifying adequacy of existing pressure relief devices.

(e) if the fluid is not 100% liquid, implementing the following steps,

(1) if the fluid is not 100% vapor, implementing the following steps,

(A) entering vapor molecular weight, vapor compressibility, vapor specific heat ration and temperature at relief pressure,

(B) defining required flow rate and cause of overpressure units for pressure relief device being sized,

(C) determining nonstandard sizing requirements,

(D) determining if relief valve goes to flare, and

(E) verifying adequacy of existing pressure relief devices.

(2) if the fluid id 100% vapor, implementing the following steps,

(A) entering vapor molecular weight vapor compressibility, vapor specific heat ration, liquid gravity, liquid viscosity, temperature and vapor pressure of liquid at relief pressure,

(B) defining required flow rate and cause of overpressure units for pressure relief device being sized,

(C) determining nonstandard sizing requirements,

(D) determining if relief valves goes to flare, and

(E) verifying adequacy of existing pressure relief devices.

23. An apparatus for determining and documenting overpressure protection due to causes of overpressure associated with equipment and pressure relief devices, the apparatus comprising:

a computer system comprising a memory device, a processing device, a program in communication with the processing device and memory device, the processing device performing tasks required by the program, the memory device further comprising;

a relational database structure, the relational database structure comprising;

(a) one or more pressure relief devices records;

(c) one or more causes of overpressure database records;

(b) one or more equipment database record, wherein the equipment database record further comprises;

(1) a link to one or more pressure relief devices records, wherein the program may access the pressure relief devices records through the equipment database record;

(2) a link to one or more causes of overpressure records, wherein the program may access the causes of overpressure records through the equipment database record.