Inspection Form
Environmental Protection Commission of Hillsborough County
Facility: Dart Container Corporation of Florida
FACILITY ADDRESS:
4610 Airport Road
Plant City, FL 33566
INSPECTION DATE:
TIME IN:
2/26/2008
2:00 p.m.
Permit No. 0570320-005-AV
Page 1 of 5
FACILITY PHONE:
(813) 752-1990
TIME OUT:
INSPECTION TYPE
STATUS:
4:00 p.m.
FCS – Type III
MNC
Date of Issuance: 8/9/2006
Expiration Date: 8/6/2011
SOURCE DESCRIPTION: Expandable Polystyrene Container Manufacturing Facility
CONTACT(S): Jimmy Rigdon, Plant Manager
The purpose of this inspection was to perform a Full Compliance Evaluation on Dart Container’s Plant City facility. Dart
Container produces foam containers made from expandable polystyrene (EPS) bead. The Air Construction Permit No.
0570320-003-AC allows the facility to increase the previously permitted expanded polystyrene (EPS) bead throughput for
the facility from 1600 lbs/hr to 2834 lbs/hr, and also construct six new pre-expanders in addition to the existing six preexpanders. This facility presently consists of eight pre-expanders which are able to operate at any given time, one
vertruder, four boilers, and various molding equipment to produce foam containers. The raw EPS beads have been
impregnated with pentane to act as a blowing agent. The small EPS beads are shipped to Dart in sealed 1000 lb
containers. The beads are placed into a hopper, and transported to the blenders. The beads from the various shipments
are blended together to obtain a uniformly mixed input stream, which is fed to holding tanks.
From the holding tanks, the beads are transported to the 8 pre-expanders, where initial bead expansion and density are
controlled. The pre-expander(s) use steam to heat the beads. The pentane, which was impregnated into the beads at the
time of manufacture, expands causing beads to expand to the desired density. The different products produced require
different initial bead sizes and densities. The expanded beads are called pre-puff. Most of the pentane emissions (90%)
from the pre-expanders are captured in the pentane recovery system and sent to the boiler for destruction. The facility
utilizes infrared sensors to measure the pentane concentration and determine the mass flow rate entering and exiting the
boilers. A totalizer keeps a total of pentane emissions from the facility.
The pre-puff is screened to remove any off-sized beads before being transferred to holding bags suspended from the
ceiling of the warehouse to await use by the cup molding process.
At the cup molding process, steam is again used to heat the pre-puff causing it to expand and fuse into the shape of the
mold. Cooling then takes place to set the shape of the container. The finished containers are inspected and are either
packaged for shipment or sent to be printed then packaged for shipment.
Any damaged or unacceptable containers are sent to be recycled. Dart uses a vertruder (vertical extruder) to recycle the
polystyrene material. Emissions from the vertruder are also captured and vented to the boiler for destruction.
Pentane emissions are captured by hoods located at the pre-expanders and are vented to the boiler(s) for destruction. These
hoods are required to capture at least 90% of the pentane emitted at the pre-expanders. The captured pentane emissions are
transferred to a main collection header which transfers the pentane emissions to the boilers. Volatile organic
compound/organic compound (VOC/OC) emissions from the pre-expander and the vertruder are controlled by
incineration in the fire side of one or any combination of the four (4) boilers on site. VOC/OC emissions from the other
facility operations are controlled through work practice standards and a facility wide emission cap.
Dart Container also has four boilers. Boiler No. 2 (EU 002) was replaced by a new Boiler No. 2R (EU 007), a 500 HP
Package Boiler, Model No. CP200-500 (steam generating unit) with a maximum heat input rate of 21 MMBtu/hr. The
existing Boiler No. 1 has a maximum heat input of 10.5 MMBtu/hr, and the Boiler No. 3 and No. 4 have a maximum heat
Inspector:
Date:
Time Spent (minutes):
Stephen Hathaway
3/24/08
720
Inspection Form
Environmental Protection Commission of Hillsborough County
Facility: Dart Container Corporation of Florida
Page 2 of 5
input of 21 MMBtu/hr and 25.2 MMBtu/hr respectively. Dart normally uses natural gas as its combustion source.
However, when natural gas is not available, Dart is able to switch to No. 2 fuel oil. Pentane emissions from the
expansion and processing of polystyrene are collected and ducted so that any boiler may serve as the pentane incinerator.
The boiler usage is dependent on steam required by the pre-expanders and cup molding machines. As steam demand
varies, boilers are cycled or turned on and off. At any given time, Dart could need only one boiler or could need 3 boilers
to produce the required steam. The run priority, the order that the boilers will be started up as steam demand requires, is
Boiler No. 4, 1, 2R, and finally Boiler No. 3. The boilers are rotated to ensure that they are all in good operating
condition. The Boiler Nos. 2R and 4 are subject to Subpart Dc of 40 CFR 60, New Source Performance Standards (NSPS).
Emissions are controlled by using Best Available Control Technology (BACT) with sulfur content limitation on fuel oil as
well as the limit on fuel usage. Dart is not a major source of hazardous air pollutants (HAPs).
As I was driving to the facility, I did not notice any visible emissions from the boiler stacks and I did not detect any odor
off-site. I did detect a faint but non-objectionable odor in the parking lot on-site upon arrival. I arrived at 2:00 p.m. and
asked to see Mr. Jimmy Rigdon, Plant Manager. After a few minutes, Jimmy greeted me and I explained the purpose of
my inspection. We then went to Jimmy’s office to discuss the inspection in more detail. I asked if there had been any
significant changes to the process operation in the last 2 years, and how many pre-expanders the facility is currently
running. Jimmy said that there were no significant changes and they currently have 8 pre-expanders and are working on
installing an additional 4 pre-expanders. I requested to inspect the recordkeeping required by the facility’s Title V Permit
since October 2006. Jimmy provided me with the records very quickly which were neat and organized. (Back at the
office, upon further examination of the recordkeeping, I discovered that there were some discrepancies about how the
facility calculated their emissions. It appeared that the spreadsheets being used to calculate monthly emissions were
utilizing the incorrect destruction efficiency percentage. The destruction efficiency used is supposed to be from the most
recent successful performance test. Also, there were a few months where the capture efficiency for the expanders was
greater than 100%. A Warning Notice may be issued for improper recordkeeping.) I examined the differential pressure
readings on each pre-expander since October 2006 and noticed a few readings below 1.5’’ w.c., which trigger inspection,
corrective action, and a reporting requirement according to the CAM Plan. I asked Mr. Rigdon what corrective measures
the facility takes when the pressure differential in each pre-expander falls below 1.5’’ w.c. He said that the z-traps above
the pre-expanders consisting of a z-shaped pipe and the p-traps below the pre-expanders are purged of condensate so that
the differential pressure will increase back to 1.5’’ w.c. or higher. On 3/29/07, I saw that the differential pressure gauge
was broken for an 8-hour period in the recordkeeping. I did not see any individual pressure readings below 0.5’’ w.c.
The lowest individual reading was 0.8’’ w.c. I asked Mr. Rigdon if Dart conducts a daily 12-minute VE test when the
boilers are being fired on fuel oil. Mr. Rigdon said that they have not burned fuel oil since before October 2006. He said
he was unaware of the requirement, but he would talk to Pam Dolbee in Dart’s Michigan office regarding the permit
condition. I asked if isopropanol is the only solvent that the facility uses and Mr. Rigdon said that is. I then asked Mr.
Rigdon to explain the vertruder process. Mr. Rigdon said that it is a vertical screw that processes in-house scrap and post
consumer styrofoam. Before being fed to the vertruder, the styrofoam is ground to 3/8’’ screen and stored in one of four
large bins. The ground styrofoam is then fed from the bins to the vertruder, which compresses and heats the styrofoam
into a resin and pentane emissions are vented through the vent zone to the boilers. The resin is cut into ribbons, cooled in
a water bath, cut into small pellets, and sold to various venders.
After discussing the vertruder operation, we headed into the plant for the walk through. We began at the vertruder
operation. At the time, the vertruder was not in operation due to not enough ground styrofoam to process. Mr. Rigdon
knocked on the storage bins to show that they were hollow. Two workers were sorting out scrap styrofoam prior to being
ground. The area around the vertruder was very neat and clean. The vent zone on the vertruder was near the bottom of
the vertical screw, and a vacuum pump is utilized to transport the pentane emissions to the main collection header. The
piping from the vent zone was connected to an accumulator which collects condensate from the operation so that it does
not interfere with the gas flow. The accumulator is periodically emptied by gravity through a bleed valve. The emissions
from the vertruder are piped through a 2’’ line all the way to the 10’’ main collection header where they are combined
Inspector:
Stephen Hathaway
Date:
3/24/08
Time Spent (minutes):
720
Inspection Form
Environmental Protection Commission of Hillsborough County
Facility: Dart Container Corporation of Florida
Page 3 of 5
with the emissions from the pre-expanders before being sent to the boilers. Pictures of the vertruder can be seen below.
We then followed the 2’’ line through the plant to the pre-expanders and it appeared that the piping was in good
condition. When we arrived at the pre-expander area, 6/8 pre-expanders were running. Number 4 and 6 were not
operating at the time. The pre-expanders were utilizing steam at the time to heat the EPS beads causing the blowing
agent to expand and increase the volume of the beads to the desired density. The expanded beads were being screened to
remove off-spec beads before being transported to the large hanging storage bags above the molding process. I asked Mr.
Rigdon if I could see the differential pressure readings on each pre-expander, and Mr. Rigdon had one of the operators
maually take the measurements for each pre-expander with a magnahelic gauge. The differential pressure readings were
all above 1.5’’ w.c. and can be seen below.
Pre-expander
1. 1.8’’ w.c.
2. 2.3’’ w.c.
3. 1.8’’ w.c.
4. not running
5. 1.9’’ w.c.
6. not running
7. 1.6’’ w.c.
8. 1.7’’ w.c.
Mr. Rigdon showed me a sample of the beads that were being fed into the pre-expanders, which are shipped to the facility
in 1000 lb large bags. The bead diameter was relatively small (on the millimeter scale). Mr. Rigdon then showed me the
pre-expanded beads which did not appear much larger than the original sized beads to the naked eye. He said that the
pre-expanded beads were 10 times the original size. I attempted to use the Gastech gas analyzer to detect pentane
concentrations around the pre-expanders, but the analyzer was malfunctioning, so I was not able to take a reading. Mr.
Rigdon and I then went to the computer display to obtain the operating parameters of the process. The computer showed
a process flow diagram with several real-time parameters such as temperatures, pressures, flow rates, and valve positions.
The operating parameters at the time were as follows:
Pentane Detector(AT 2000) 1319 ppm and 8.9% LEL
Pentane flow rate
33.7 lbs/hr
Pre-expander valves
Open
Inspector:
Stephen Hathaway
Date:
3/24/08
Time Spent (minutes):
720
Inspection Form
Environmental Protection Commission of Hillsborough County
Facility: Dart Container Corporation of Florida
Boiler header pressure
Boiler header temperature
Blower frequency
Boiler No. 1
Differential pressure
Flow rate
Temperature
Boiler No. 2R
Differential pressure
Flow rate
Temperature
Boiler No. 3
Differential pressure
Flow rate
Temperature
Boiler No. 4 (off)
Differential pressure
Flow rate
Temperature
Page 4 of 5
10.0’’ w.c.
118 deg F
55 Hz
3.9’’ w.c.
962 scfm
305 deg F
2.9’’ w.c.
883 scfm
256 deg F
2.6’’ w.c.
353 scfm
313 deg F
0.1’’ w.c.
0 scfm
152 deg F
I then obtained a computer printout of the boiler temperatures and flow rates at the time of my inspection. After that, we
went into the boiler room to inspect the 4 natural gas fired boilers which provide process steam while simultaneously
destroying the pentane emissions. Mr. Richard Brown, one of the boiler operators accompanied us in the boiler room. I
recorded the nameplate data and steam pressure for each boiler which can be seen below. The boiler model numbers
corresponded to the boilers referenced in the facility’s Title V Permit.
Boiler No.
1
2R
3
4
Manufacturer
Cleaver Brooks
Cleaver Brooks
Orr and Sembower
Cleaver Brooks
Model No.
CB 400-500
CP 200-500
250 HP 3LG
CB 200-600
Date
10/12/1972
12/28/1984
1964
5/23/1986
Steam
Pressure
90 psig
88 psig
100 psig
0 psig
I then asked Mr. Brown how often the flame arrestors are cleaned and he said it depends on demand and usage, but they
try to clean them when the filter pressure reaches 2.5-3 psig in order to ensure they are operating properly. A picture of
Boiler No. 4 with its associated flame arrestor can be seen below.
Inspector:
Stephen Hathaway
Date:
3/24/08
Time Spent (minutes):
720
Inspection Form
Environmental Protection Commission of Hillsborough County
Facility: Dart Container Corporation of Florida
Page 5 of 5
After inspecting the boilers and the associated ductwork, I told Mr. Rigdon that I did not observe any obvious problems
during my inspection, but if I found anything later on, I would let him know. I said I would be in touch with him if I
needed any additional information. We then went back to the main office to gather the pertinent records and belongings
and then I departed from the facility at 4:00 p.m.
See also: EASIIR Inspection Report
Inspector:
Stephen Hathaway
Date:
3/24/08
Time Spent (minutes):
720