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Learn From Case Study of Industrial Heat Exchanger Explosion

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00:00:14.360 00:00:14.370 00:00:16.110 00:00:16.120 June 13th 2013 the Williams guys marol
00:00:20.830 00:00:20.840 offense plant in guys Mar Louisiana a
00:00:23.410 00:00:23.420 heat exchanger violently ruptured
00:00:25.890 00:00:25.900 causing an explosion and fire that
00:00:28.900 00:00:28.910 killed two workers the Chemical Safety
00:00:31.390 00:00:31.400 Board launched an investigation and
00:00:33.310 00:00:33.320 issued a case study in it the agency
00:00:36.730 00:00:36.740 describes a number of process safety
00:00:38.979 00:00:38.989 management program deficiencies at
00:00:41.200 00:00:41.210 Williams which set the stage for the
00:00:43.900 00:00:43.910 incident in particular the CSB found
00:00:47.290 00:00:47.300 that the heat exchanger that failed was
00:00:49.180 00:00:49.190 completely isolated from its pressure
00:00:51.310 00:00:51.320 relief valve when pressure inside the
00:00:53.860 00:00:53.870 heat exchanger dangerously increased
00:00:55.990 00:00:56.000 there was nothing to stop a catastrophic
00:00:58.330 00:00:58.340 rupture
00:01:00.349 00:01:00.359 our case study on the explosion at
00:01:02.689 00:01:02.699 Williams describes an ineffective
00:01:04.609 00:01:04.619 process safety management program at the
00:01:06.800 00:01:06.810 plant at the time of the incident
00:01:08.960 00:01:08.970 we urge other companies to learn from
00:01:11.630 00:01:11.640 our investigation to incorporate our
00:01:13.760 00:01:13.770 recommendations at their facilities and
00:01:15.770 00:01:15.780 to assess the current state of their
00:01:18.230 00:01:18.240 process safety culture so that a similar
00:01:20.660 00:01:20.670 accident can be averted the Williams
00:01:30.560 00:01:30.570 guys Marv olefins plant is located in
00:01:33.200 00:01:33.210 Geismar Louisiana the plant produces
00:01:35.779 00:01:35.789 ethylene and propylene these are
00:01:38.359 00:01:38.369 chemicals used in the petrochemical
00:01:40.010 00:01:40.020 industry to make a variety of products
00:01:42.889 00:01:42.899 including plastics and antifreeze within
00:01:46.219 00:01:46.229 the Williams process is a distillation
00:01:48.410 00:01:48.420 column called the propylene fractionator
00:01:51.260 00:01:51.270 it separates a mixture of propane and
00:01:54.080 00:01:54.090 propylene heat exchangers called
00:01:56.660 00:01:56.670 reboilers supply heat to the
00:01:59.120 00:01:59.130 fractionator to boil the propane and
00:02:01.639 00:02:01.649 propylene mixture which is essential to
00:02:03.770 00:02:03.780 the separation process the reboilers are
00:02:06.830 00:02:06.840 shell and tube heat exchangers hot water
00:02:09.800 00:02:09.810 flows through the tubes heating and
00:02:12.380 00:02:12.390 vaporizing propane that flows through
00:02:15.080 00:02:15.090 the shell and back to the propylene
00:02:17.449 00:02:17.459 fractionator the water that flows
00:02:19.550 00:02:19.560 through the tubes contains a small
00:02:21.320 00:02:21.330 amount of oily tar which condenses into
00:02:24.229 00:02:24.239 the water earlier in the process over
00:02:26.630 00:02:26.640 time the oily tar from the water builds
00:02:29.240 00:02:29.250 up on the walls of the reboiler tubes
00:02:31.190 00:02:31.200 this buildup is called fouling fouling
00:02:35.149 00:02:35.159 reduces the efficiency of the reboilers
00:02:37.750 00:02:37.760 periodically the reboilers must be shut
00:02:40.280 00:02:40.290 down to clean the tubes the original
00:02:43.100 00:02:43.110 propylene fractionator design had both
00:02:45.800 00:02:45.810 reboilers running simultaneously but in
00:02:49.130 00:02:49.140 that configuration the fractionator had
00:02:51.619 00:02:51.629 to be shut down when a reboiler fouled
00:02:54.050 00:02:54.060 and needed cleaning to prevent shutdown
00:02:57.259 00:02:57.269 of the propylene fractionator each time
00:02:59.660 00:02:59.670 the reboilers needed to be clean in 2001
00:03:03.289 00:03:03.299 new valves were installed on each
00:03:06.080 00:03:06.090 reboiler to allow for operation of only
00:03:09.240 00:03:09.250 the time the other reboiler is on
00:03:11.910 00:03:11.920 standby clean and ready for use
00:03:14.700 00:03:14.710 but unforeseen at the time these valves
00:03:17.340 00:03:17.350 introduced a serious hazard they
00:03:19.680 00:03:19.690 isolated the standby reboiler from its
00:03:22.260 00:03:22.270 protective pressure relief valve located
00:03:24.750 00:03:24.760 on top of the fractionator on June 13
00:03:28.070 00:03:28.080 2013 during a daily meeting with
00:03:31.230 00:03:31.240 operations and maintenance personnel the
00:03:34.080 00:03:34.090 williams plant manager noticed that the
00:03:36.180 00:03:36.190 water flow rate through the operating
00:03:38.190 00:03:38.200 reboiler had dropped gradually over the
00:03:41.220 00:03:41.230 past day the operation supervisor
00:03:43.590 00:03:43.600 informed the group he would try to
00:03:45.420 00:03:45.430 identify the problem he went into the
00:03:47.970 00:03:47.980 plant to evaluate the water flow rates
00:03:50.190 00:03:50.200 the operation supervisor informed
00:03:52.620 00:03:52.630 several personnel that fouling within
00:03:55.199 00:03:55.209 the operating reboiler could be the
00:03:57.449 00:03:57.459 problem and they might need to switch
00:03:59.280 00:03:59.290 the reboilers he attempted to meet with
00:04:01.890 00:04:01.900 his manager so they could get the
00:04:03.360 00:04:03.370 necessary maintenance and operations
00:04:05.430 00:04:05.440 personnel involved who would perform the
00:04:08.040 00:04:08.050 work but his manager was not available
00:04:10.590 00:04:10.600 the operation supervisor returned to the
00:04:13.289 00:04:13.299 field the CSB determined that at 8:33
00:04:16.560 00:04:16.570 a.m. the operation supervisor likely
00:04:20.310 00:04:20.320 opened the water valves on the standby
00:04:22.500 00:04:22.510 reboiler hot water began flowing inside
00:04:25.620 00:04:25.630 the valves blocking the reboiler from
00:04:28.260 00:04:28.270 its protective pressure relief valve
00:04:30.030 00:04:30.040 remained closed but unknown to the
00:04:33.120 00:04:33.130 operation supervisor the standby
00:04:35.550 00:04:35.560 reboiler contained flammable liquid
00:04:37.710 00:04:37.720 propane that had accumulated during the
00:04:40.080 00:04:40.090 16 months the reboiler was out of
00:04:42.630 00:04:42.640 service the hot water quickly heated the
00:04:45.330 00:04:45.340 liquid propane confined inside of the
00:04:48.000 00:04:48.010 reborn
00:04:48.610 00:04:48.620 and pressure dangerously increased just
00:04:51.820 00:04:51.830 three minutes later the reboiler
00:04:53.860 00:04:53.870 violently ruptured propane exploded from
00:04:58.270 00:04:58.280 the reboiler and ignited to create a
00:05:00.820 00:05:00.830 massive fireball the explosion killed
00:05:03.790 00:05:03.800 the operations supervisor and an
00:05:06.070 00:05:06.080 operator working nearby 167 williams
00:05:09.700 00:05:09.710 employees and contractors reported being
00:05:12.730 00:05:12.740 injured during its investigation the CSB
00:05:16.570 00:05:16.580 found that prior to the explosion the
00:05:19.210 00:05:19.220 standby reboiler had been out of service
00:05:21.219 00:05:21.229 for over a year isolated from the
00:05:23.770 00:05:23.780 process by closed block valves but
00:05:26.740 00:05:26.750 during this 16 month period
00:05:28.960 00:05:28.970 liquid propane unintentionally entered
00:05:31.750 00:05:31.760 the shell of the reboiler perhaps
00:05:33.670 00:05:33.680 through a mistakenly opened valve or a
00:05:36.400 00:05:36.410 leaking back valve the CSB determined
00:05:39.550 00:05:39.560 that when the Operations Supervisor
00:05:40.860 00:05:40.870 opened the hot water valves to the
00:05:43.300 00:05:43.310 standby reboiler the propane liquid
00:05:45.520 00:05:45.530 crapped inside was heated and expanded
00:05:48.219 00:05:48.229 in volume to completely fill the
00:05:50.620 00:05:50.630 reboiler shell this caused pressure to
00:05:53.290 00:05:53.300 dramatically increase until the reboiler
00:05:56.200 00:05:56.210 ruptured when identifying overpressure
00:05:58.719 00:05:58.729 protection requirements for heat
00:06:00.790 00:06:00.800 exchangers engineers should evaluate the
00:06:03.610 00:06:03.620 scenario that caused the Williams
00:06:05.260 00:06:05.270 explosion the hot side of the heat
00:06:07.450 00:06:07.460 exchanger was operated while the cold
00:06:09.940 00:06:09.950 side was blocked in in this scenario
00:06:12.909 00:06:12.919 just having a pressure relief valve
00:06:14.980 00:06:14.990 available could have prevented the
00:06:17.110 00:06:17.120 explosion the CSB discovered that in the
00:06:20.170 00:06:20.180 12 years leading to the incident a
00:06:22.240 00:06:22.250 series of process safety management
00:06:23.920 00:06:23.930 program deficiencies caused the reboiler
00:06:27.189 00:06:27.199 to be unprotected from overpressure when
00:06:30.430 00:06:30.440 Williams installed the process block
00:06:32.290 00:06:32.300 valves on the reboilers in 2001 they
00:06:35.200 00:06:35.210 performed a management of change review
00:06:37.180 00:06:37.190 to identify how this action affected the
00:06:40.060 00:06:40.070 safety of the process the CSB found
00:06:42.580 00:06:42.590 however that Williams did not identify
00:06:44.529 00:06:44.539 that the new valves could isolate the
00:06:47.260 00:06:47.270 reboilers from their protective pressure
00:06:49.150 00:06:49.160 relief valve
00:06:51.110 00:06:51.120 companies are required to conduct a
00:06:53.490 00:06:53.500 management of change review before
00:06:55.589 00:06:55.599 making equipment changes so they may
00:06:57.839 00:06:57.849 consider the impact of that change on
00:07:00.270 00:07:00.280 the safety of the process but the CSB
00:07:02.670 00:07:02.680 discovered that Williams conducted the
00:07:04.529 00:07:04.539 management of change review after the
00:07:06.719 00:07:06.729 process was already operating with the
00:07:08.760 00:07:08.770 new valves we concluded that Williams
00:07:11.459 00:07:11.469 conducted the delayed management have
00:07:13.980 00:07:13.990 changed to meet regulatory requirements
00:07:16.529 00:07:16.539 at that point rather than to use it as a
00:07:19.140 00:07:19.150 tool to identify and control new process
00:07:22.290 00:07:22.300 hazards that was a serious missed
00:07:24.659 00:07:24.669 opportunity to identify the new
00:07:27.540 00:07:27.550 overpressure hazard that was introduced
00:07:29.790 00:07:29.800 to the process by the new valves after
00:07:33.180 00:07:33.190 the 2001 reboiler valve installation
00:07:35.520 00:07:35.530 Williams also performed a pre startup
00:07:38.129 00:07:38.139 safety review as required by regulations
00:07:40.830 00:07:40.840 but the CSB found that Williams
00:07:43.649 00:07:43.659 reviewers did not respond to key process
00:07:46.800 00:07:46.810 safety questions on the form one of
00:07:49.170 00:07:49.180 those questions asked are pressure
00:07:51.360 00:07:51.370 relief systems in place and operational
00:07:53.450 00:07:53.460 that answer was left blank even though
00:07:57.510 00:07:57.520 the pre startup safety review document
00:07:59.879 00:07:59.889 was incomplete and there were questions
00:08:01.860 00:08:01.870 that were not answered management
00:08:04.320 00:08:04.330 approved at the forum and the end result
00:08:06.839 00:08:06.849 was these reboilers were put into
00:08:08.700 00:08:08.710 service without adequate overpressure
00:08:10.950 00:08:10.960 protection the CSB found that in the
00:08:13.860 00:08:13.870 following 10 years Williams performed
00:08:16.409 00:08:16.419 three process hazard analysis or PHAs in
00:08:20.309 00:08:20.319 2001 2006 and 2011
00:08:24.059 00:08:24.069 none of the PHAs sufficiently identified
00:08:27.719 00:08:27.729 or controlled the reboiler overpressure
00:08:30.899 00:08:30.909 hazard an internal recommendation on the
00:08:33.630 00:08:33.640 2006 PHA stated consider locking open at
00:08:38.310 00:08:38.320 least one of the manual valves
00:08:40.649 00:08:40.659 associated with each of the propylene
00:08:42.959 00:08:42.969 fractionated reboilers while that
00:08:45.630 00:08:45.640 recommendation was marked as complete
00:08:48.700 00:08:48.710 yes we found that it was not implemented
00:08:51.250 00:08:51.260 as intended a process valve on the
00:08:53.920 00:08:53.930 operating reboiler was locked open but a
00:08:57.310 00:08:57.320 process valve on the standby reboiler
00:08:59.590 00:08:59.600 was not locked open even though the PHA
00:09:03.100 00:09:03.110 recommended that valves on bo3 boilers
00:09:06.250 00:09:06.260 should be locked open so that the
00:09:08.530 00:09:08.540 reboiler had an open path to pressure
00:09:10.720 00:09:10.730 relief and the CSB found that Williams
00:09:14.440 00:09:14.450 failed to develop a procedure for
00:09:16.090 00:09:16.100 activities performed on the day of the
00:09:18.310 00:09:18.320 incident as following in the quench
00:09:20.200 00:09:20.210 water system was a known issue Williams
00:09:22.720 00:09:22.730 should have had a written procedure to
00:09:24.700 00:09:24.710 assess fouling and switch the reboilers
00:09:27.220 00:09:27.230 furthermore the company could have
00:09:28.840 00:09:28.850 established a routine maintenance
00:09:30.100 00:09:30.110 schedule to prevent extensive fouling in
00:09:32.620 00:09:32.630 the first place one of the key lessons
00:09:34.930 00:09:34.940 from this incident is the importance of
00:09:37.150 00:09:37.160 detail when implementing process safety
00:09:39.760 00:09:39.770 programs if a critical detail is
00:09:42.580 00:09:42.590 overlooked in an MOC in a PSS are a
00:09:46.360 00:09:46.370 safeguard evaluation or a PHA a
00:09:49.350 00:09:49.360 significant hazard can be missed and
00:09:52.420 00:09:52.430 this can lead to a major incident
00:09:54.700 00:09:54.710 sometimes years later at Williams the
00:09:58.510 00:09:58.520 overpressure hazard was overlooked in
00:10:01.480 00:10:01.490 that very first MOC and that contributed
00:10:04.780 00:10:04.790 to the explosion that occurred 12 years
00:10:07.060 00:10:07.070 later to prevent future incidents and
00:10:10.210 00:10:10.220 further improve process safety at the
00:10:12.490 00:10:12.500 guys mark plant the CSB recommended that
00:10:15.160 00:10:15.170 williams conduct safety culture
00:10:17.200 00:10:17.210 assessments that involve workforce
00:10:19.540 00:10:19.550 participation and communicate the
00:10:21.730 00:10:21.740 results in reports that recommend
00:10:23.710 00:10:23.720 specific actions to address safety
00:10:26.170 00:10:26.180 culture weaknesses develop a robust
00:10:28.810 00:10:28.820 safety indicators tracking program that
00:10:31.330 00:10:31.340 uses the data identified to drive
00:10:33.820 00:10:33.830 continual safety improvement and perform
00:10:36.990 00:10:37.000 comprehensive process safety program
00:10:39.430 00:10:39.440 assessments to thoroughly evaluate the
00:10:41.740 00:10:41.750 effectiveness of the facility's process
00:10:44.200 00:10:44.210 safety programs in its case study the
00:10:47.530 00:10:47.540 CSB encourages companies from across the
00:10:50.020 00:10:50.030 country to review and incorporate the
00:10:52.390 00:10:52.400 safety lessons and recommendations
00:10:54.790 00:10:54.800 from the Williams guys Mar plant
00:10:56.560 00:10:56.570 investigation within their own
00:10:58.630 00:10:58.640 facilities many of the incidents that
00:11:00.880 00:11:00.890 the CSB has investigated could have been
00:11:03.220 00:11:03.230 prevented if an effective process safety
00:11:05.980 00:11:05.990 management program had been in place at
00:11:07.870 00:11:07.880 the facility managers must implement and
00:11:10.780 00:11:10.790 then monitor these programs and
00:11:12.910 00:11:12.920 encourage a strong culture of safety to
00:11:15.610 00:11:15.620 protect workers and the environment for
00:11:20.290 00:11:20.300 further information about the CSB is
00:11:22.240 00:11:22.250 Williams guy smart plant investigation
00:11:24.519 00:11:24.529 please visit CSB
00:12:03.310 00:12:03.320

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