2012 Honeywell Users Group EMEA

Transcription

1 2012 Honeywell Users Group EMEA Sustain.Ability. Case Study: Holly Frontier Navajo Refining Regulatory Controls Enhance Safety and Assist in Environmental Compliance while Providing Economic Benefits Andy Coward, Honeywell

2 Agenda Background on Navajo Refinery Problem statement Method of resolution Specific examples Lessons learned Questions 2

3 Agenda Background on Navajo Refinery Problem statement Method of resolution Specific examples Lessons learned Questions 3

4 Introduction The Navajo Refinery is located in Artesia, New Mexico and has a crude oil capacity of 100,000 barrels per day. The Navajo Refinery can process heavy, sour and light, sweet crude oils and runs a predominant slate of Permian Basin crudes that are gathered in West Texas and Southeast New Mexico. The refinery can also source a variety of crude oils from Cushing, Oklahoma including Canadian crudes. The Navajo refinery serves markets in the Southwestern United States and Northern Mexico. 4

5 Agenda Background on Navajo Refinery Problem statement Method of resolution Specific examples Lessons learned Questions 5

6 An Operating Culture That Develops Over Time For many years Navajo Refining had very experienced managers that took a hands on approach to refinery operations Units ran well, but with a large amount of operator intervention Operators compensated as instrumentation developed issues, operating conditions changed etc. No formal maintenance or management process No MOC/tuning campaigns 6

7 The Times - They Were A Changing As new process units were added to meet market requirements more and more loops were added to the operators load. Trying to do even more mandraulic activities Experienced staff began to retire, but the culture of a hands on approach to operations continued. A cycle of non-improvement began to develop That controller has always run in manual Maintenance has tried and tried to fix it Just fuggeddaboutit! 7

8 The Operating Culture Needed to Change Over time it was observed that More and more loops were in manual (30% on some units) Environmental incidents increased and became more of a problem Safety incidents were on the rise Inferior regulatory control was thought to be a significant part of the problem. How to change the culture? 8

9 How to Change the Operating Culture This is among the most difficult things leaders can do. Changing the beliefs and assumptions about what is possible, ways of perceiving problems and thinking through solutions is not easy To create an operating culture that believes the following is the norm; Operator interventions can be reduced Control loops can and should operate in automatic mode Good performance is possible and expected Improvement is the norm 9

10 Agenda Background on Navajo Refinery Problem statement Method of resolution Specific examples Lessons learned Questions 10

11 Breaking the Cycle To break the cycle of non-improvement, Navajo decided to implement a regulatory control improvement program using an outside resource The reasoning was to augment the refinery technical expertise that would help break this cycle Specifically the skillset required was Regulatory control knowledge (DCS and Field) Process Engineering knowledge (Refining) Operations experience (Refining) Honeywell provided this resource! 11

12 Developing the Program A resource was identified that had the following Regulatory control and DCS experience Refinery process engineering experience Operations experience Ability to communicate to both technical, maintenance and operations staff Ability to commit long term to the program Refinery staff prioritized the work based on need Safety, Environmental, Quality, New Unit Startup, etc. 12

13 The Program Begins Work began with tuning controllers in a new IsoTherming Mild Hydrocracking Unit (MHU) The process was relatively new being the second installation of a VGO Mild Hydrocracker using this technology Specific control learnings Initial Reactor level measurements using dp cells were unreliable replaced with nuclear level detectors Residual Gas Analysis indicated a different pairing for reactor pressure control. Improved reactor pressure control helped stabilized the reactor operation. 13

14 Initial Program Progress In the first 3 months 375 hours were spent working on about 160 loops in 12 refinery units as identified by refinery staff. 60 percent of these loops were successfully tuned for improved performance. A number of loops required maintenance before tuning could be done. Measurement exceeding range limits or frozen Saturated valves were common and Work orders were issued and followed up. 14

15 Initial Program Progress Process issues sometimes prevented loops form functioning. Insufficient overhead liquid in some distillation columns caused loss of reflux and pump problems requiring a review of operating targets Temporary low unit feed rates or other unusual process operating conditions caused some measurements and valves to become unreliable In a few cases, operators were resistant to having the loop tuned because they felt the loop was too sensitive 15

16 How was Done was accomplished using OperTune. This provided a standard methodology and created a traceable record of tuning. The methodology is straight forward Observe valve position and measurement are in a reasonable range Stabilize loop in manual Apply PV filtering is needed Move valve and observe if measurement responds; if valve sticks; determine move size and settling time 16

17 How was Done The methodology continued Perform step test on loop (can be open or closed loop) After test completion, select tuning constants based on desired performance (a set of ten are provided) Have operator move the set point in both directions and observe performance Have operator create a load disturbance if possible and observe performance Adjust tuning as necessary Observe performance over the next few days using either the DCS or historian trending capability 17

18 18 Example: Crude Preflash Level

19 Continuing Efforts Since program inception, work has continued on improving regulatory control performance 172 additional loops have been identified as having performance issues Of those loops, 68 percent were successfully tuned for improved performance Some of these include complex regulatory strategies that had to be re-scaled and documented before tuning Hydrogen unit capacity and S/C ratio control Hydrogen unit reformer firing control 19

20 Agenda Background on Navajo Refinery Problem statement Method of resolution Specific examples Lessons learned Questions 20

21 Specific Operational Needs New Residuum Oil Supercritical Extraction (ROSE) and PSA units start up Loops tuned as start-up engineers directed Improved performance around critical equipment Mild Hydrocracker hydrogen recycle compressor Improve spillback control performance for better stability and reduced trips. 21

22 22 MHC Spillback Controls

23 1 st Stage Pressure Control Before After 23

24 2nd Stage Pressure Control Before After 24

25 3 rd Stage Pressure Control Before After 25

26 4 th Stage Pressure Control Before After 26

27 Statistical Evidence 1 st Stage 2 nd Stage Before SP PV OP After Before After Before After Mean Standard Deviation Before SP PV OP After Before After Before After Mean Standard Deviation rd Stage 4 th Stage Before SP PV OP After Before After Before After Mean Standard Deviation Before SP PV OP After Before After Before After Mean Standard Deviation

28 Better Control Better Environmental Compliance Sulfur plant incinerators oxidize sulfur compounds that cannot be vented to the environment. 2H 2 S + 3O 2 2SO 2 + 2H 2 O 2COS + 3O 2 2SO 2 + 2CO 2 CS 2 + 3O 2 2SO 2 + 2CO 2 Temperature must be maintained above the highest autoignition temperature of the compounds to be oxidized (1128 F for CO) Stability is therefore paramount for environmental performance 31

29 Deg. F Output, % Incinerator Temperature Control TIC427 Incinerator Temperature : : : : : : : :00 Time 31TIC427.DACA.PV 31TIC427.PIDA.SP 31TIC427.PIDA.OP 32

30 Agenda Background on Navajo Refinery Problem statement Method of resolution Specific examples Lessons learned Questions 33

31 Lessons Learned Technology alone does not address the problems Culture change Management of change process Success favours behaviour change Continual support to drive behaviour Additional loops that were identified! 34

32 Regulatory Control Improvement A sustained program for Regulatory Control Improvement for Navajo Refinery has provided Increased process stability Increased percentage of loops in normal mode (auto, cascade, etc.) 95% versus 60% initially Reduced operator intervention Reduced process trips Reduced environmental incidents Improved base for which APC can be implemented 35

33 Agenda Background on Navajo Refinery Problem statement Method of resolution Specific examples Lessons learned Questions 36

34 37 Questions?