Method for operating a cryogenic plant

• US 6,666,049 B1
• Filed: 03/20/2003
• Issued: 12/23/2003
• Est. Priority Date: 03/20/2003
• Status: Active Grant

• Current Assignee: Praxair Technology Incorporated (Linde Plc)
• Original Assignee: Praxair Technology Incorporated (Linde Plc)
• Inventors: Gupta, Amit, Katende, Edward, Scharf, Paul F.
• Primary Examiner(s): Paik, Sang Y.
• Assistant Examiner(s): Drake, Malik N.
• Application Number:
  US10/391,557
• Time in Patent Office: 278 Days
• Field of Search: 626/17, 626/40, 626/43, 626/56, 626/57
• US Class Current: 62/656
• CPC Class Codes: F25J 2280/50 Advanced process control, e.g. adaptive or multivariable control
• CPC Class Codes: F25J 2290/10 Mathematical formulae, modeling, plot or curves; Design methods
• CPC Class Codes: F25J 3/0223 H2/CO mixtures, i.e. synthesis gas; Water gas or shifted synthesis gas production of carbon monoxide containing gas in general C01B32/40, C10J, C10K; production of hydrogen containing gas C01B3/00
• CPC Class Codes: F25J 3/0252 separation of hydrogen production of hydrogen containing gas in general C01B3/00, e.g. separation of hydrogen or hydrogen containing gases form gaseous mixtures at low temperatures C01B3/506
• CPC Class Codes: F25J 3/0261 separation of carbon monoxide production of carbon monoxide containing gas in general C01B32/40, C10J, C10K
• CPC Class Codes: F25J 3/0266 separation of carbon dioxide production of carbon dioxide in general C01B32/00
• CPC Class Codes: F25J 3/0295 Start-up or control of the process; Details of the apparatus used, e.g. sieve plates, packings
• CPC Class Codes: F25J 3/0409 of oxygen
• CPC Class Codes: F25J 3/04412 in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
• CPC Class Codes: F25J 3/04678 cooled by oxygen enriched liquid from high pressure column bottoms
• CPC Class Codes: F25J 3/048 Argon recovery
• CPC Class Codes: F25J 3/04848 Control strategy, e.g. advanced process control or dynamic modeling
• CPC Class Codes: G05B 23/0229 knowledge based, e.g. expert systems; genetic algorithms
• CPC Class Codes: G05B 23/0289 Reconfiguration to prevent failure, e.g. usually as a reaction to incipient failure detection
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A method for operating a cryogenic plant using an online real-time monitoring and diagnostic system that continually compares actual versus expected plant key performance indicators, alerts operating personnel to any significant performance shortfall, assists in required diagnostics, and suggests corrective actions, preferably using a top-down diagnostic tree methodology that presents calculated key performance indicators to the operator in a manner which logically flows from plant overview to detailed breakdown by plant area and equipment component.

Claims

1. A method for operating a cryogenic plant comprising:

(A) determining the expected optimal value range at a given time using a process model for at least one key performance indicator from the group consisting of plant power consumption, product recovery, PID loop performance, MPC steady state optimization, MPC model prediction and MPC dynamic performance;

(B) monitoring the value of each of the key performance indicators for which an expected optimal value range has been determined;

(C) alerting a plant operator when the value of a monitored key performance indicator is outside of the determined expected optimal value range for that key performance indicator; and

(D) suggesting at least one action to the plant operator for adjusting the operation of the cryogenic plant so that the value of the monitored key performance indicator which is outside of the expected optimal value range for that key performance indicator is changed so that it is within the expected optimal value range for that key performance indicator.

2. The method of claim 1 wherein the cryogenic rectification plant is a cryogenic air separation plant.

3. The method of claim 1 wherein the monitored key performance indicators comprises plant power consumption.

4. The method of claim 1 wherein the expected optimal value range is calculated using a mathematical process model.

5. The method of claim 1 wherein the alerting of the plant operator is by a screen display.

6. The method of claim 5 further comprising altering other personnel by e-mail.

7. The method of claim 1 wherein the suggesting of action to the plant operator is by a screen display.

8. The method of claim 7 further comprising sending a detailed report by e-mail to other personnel.

9. The method of claim 1 wherein the suggestion for action is determined using a top-down diagnostic tree methodology.

10. The method of claim 9 wherein the suggestion for action is indicated to the plant operator by a screen display.