Lendell Manufacturing Incorporated - Executive Summary |
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7 Polyurethane foam and prepolymer manufacturing facility The polyurethane foam and prepolymer facility (see fig. 1) uses the risk management program (RMP) regulated substance 80:20 TDI (i.e., 80 wt% 2-4-TDI and 20 wt% 2-6-TDI) in the prepolymer manufacturing process. The prepolymer product contains 3 wt% TDI and is stored in product containers for later use to produce polyurethane foam. The closest public receptor to the TDI process equipment is Karlen manufacturing. This business is about 206 ft. from the prepolymer manufacturing building, and 300 ft from the foam-manufacturing site. We have a direct connection with the Tri-Township Fire Department for emergency response, as well as periodic inspections from Bayer Chemical to ensure a safe setup of the manufacturing facility. The facility uses administrative controls to limit the amount of TDI present at any one time, as to maintain a TDI quantity safety factor. The main TDI tank area is not only diked off, but enclosed in a s eparate room for isolation purposes. This room can only exhaust air through a scrubber, which neutralizes TDI vapors. All related personnel are trained at least annually and have access to all necessary safety equipment for proper handling. Spill response training is also included for appropriate personnel. Regular safety meetings update any need for changes to keep safety issues current. The safe manner in which this facility is handled has resulted in no accidental releases in the history of the facility. The following locations and equipment in the coatings manufacturing process handle TDI: 7 The TDI storage tank. The 40,000-lb indoor TDI storage tank stores TDI, and provides TDI to the prepolymer manufacturing process. Administrative controls keep no more than 27,000 lbs. of TDI on site. The tank is contained in a 33-ft by 22-ft dike area. The height of the dike is 2 ft. 7 The Reactor. TDI from the TDI storage tank is pumped to the 2000-LB reactor, where TDI is reacted with other substances to produce polyurethane prepolymer. The prepolymer (3 wt%TDI) is then dumped into product containers, which are conditioned for use in the foam manufacturing area. The reactor and storage tank are confined into a separate inner building area, which can be sealed off from the rest of the plant. 7 Product containers. A variety of product containers may be used for product containment, the largest and most widely used being a 3000-lb container (typically filled with 2000-lbs of product.) 7 The TDI lines that connect the tank to the reactor. The estimated 39-ft of line contain approximately 25 lbs. of TDI. 7 The foam production line stores up to 2-2,000 lbs. product containers of 3 wt% TDI. 7 The mix head/lines. The mix head mixes the prepolymer with the other polymerization reactants and discharges the mixture onto a conveyor belt. The entire mix equipment contains up to 300 lbs. of the 3 wt% TDI. 7 Conveyor system. Polyurethane foam is created when the polym erization reactants are discharged from the mixing head onto the conveyor. The equipment and handling downstream of the conveyor system handles only polyurethane foam and is not covered by the RMP rule requirements. Guidance on the worksheets for this process. The following notes help explain some of the steps in filling out the worksheets for this process: 7 The capacity of the piping is determined using equation 1 below: Capacity = (75.8 pcf) x (3.14) x (0.0521)2 = 25 lbs. (Eq. 1) 7 The area surrounding the facility is relatively flat and unobstructed, indicating the endpoint distance table for rural topography should be used for all scenarios. 7 The majority of TDI in the prepolymer is reacted to form a polyol-TDI polymer that is not regulated by the RMP rule. However, the free TDI (3 wt%) is regulated by the RMP rule. The quantity of TDI in all the product containers is determined by the following equation: QTDI = (3 wt %) x (20,800 lbs.) = 625 lbs. 7 The reactor is loaded with no more than 700 lbs. of TDI during the prepolymer manufacture. It is then reacted to form the 3 wt% prepolymer. 7 The total capacity of the mixhead/lines is approximately 300 lbs. prepolymer. However, the free TDI in the prepolymer (3 wt%) is regulated by the RMP rule. The quantity of TDI in the mixhead/lines is determined by the following equation: QTDI = (3 wt %) x (300 lbs.) = 9 lbs. 7 The cast foam product on the conveyor line is not covered by the RMP rule because the TDI is completely reacted to form the foam product. 7 A worst case scenario analysis must be performed for the TDI storage tank release and not from the product storage containers. Even though the TDI storage tank is diked and falls under mitigating circumstances of building confinement, this scenario has the potential to result in a greater endpoint distance than a release from the product containers. 7 The quantity contained in the diked area surrounding the TDI storage tank is determined using equatio n 2 below: Qdike = (75.8pcf) x (632 ft2) x (2 ft) = 95,811 LB TDI (Eq. 2) The tank holds a maximum capacity of 40,000 lbs., but due to administrative controls, no more than 27,000 lbs. is stored. Therefore, Apool = Adike = 632 ft2. 7 The linear interpolation method for estimating the worst-case release endpoint distance presented in this document overestimates the endpoint distance for the facility warehouse- the method does not consider the mitigating effect of the warehouse on the release. 7 The temperature of the TDI in the tank trucks at delivery is typically less than 850F. Therefore an interpolated 900F table was generated. 7 The endpoint distance resulting from the rupture of the TDI bulk tank is determined using linear interpolation of values given in the endpoint distance lookup tables. Because the TDI bulk tank is maintained at 850F, an interpolated 900F table was generated. Because the dike contains the release, the pool area for this scenario is 632 ft2. The fol lowing excerpts from the endpoint distance lookup tables and the interpolation formula describe this calculation. Worst-case Release Scenario Endpoint Distances for TDI - Rural Topography (excerpt & interpolated) Release-------Pool---------------Distance (ft) Quantity-------Area----------78 F-90 F-95 F-100 F 625 LB-------250 ft2---------88---NA---144---160 1250 LB------500 ft2--------130--179--200---220 2500 LB-----1000 ft2--------180--251--281---310 Interpolated endpoint distances for 500 sq. ft. area of TDI at 950F: D = 130 ft + (950F - 780F/1000F-780F) x (220ft - 130ft) = 200 ft Interpolated endpoint distances for 1000 sq. ft. area of TDI at 950F: D = 180 ft + (950F - 780F/1000F-780F) x (310ft - 180ft) = 281 ft Interpolated endpoint distances for 500 sq. ft. area of TDI at 900F: D = 130 ft + (900F - 780F/1000F-780F) x (220ft - 130ft) = 179 ft Interpolated endpoint distances for 1000 sq. ft. area of TDI at 900F: D = 180 ft + (900F - 780F/1000F -780F) x (310ft - 180ft) = 251 ft Endpoint distance for a 250 sq. ft. area of TDI at 950F: D = 88ft + (950F - 780F/1000F-780F) x (160ft - 88ft) = 144 ft Endpoint distance for a 632 sq. ft. area of TDI at 900F: D = 179ft + (632 - 500/1000 - 500 sq. ft.) x (251 - 179 ft) = 198 ft. Coverage Assessment Process Description Worksheet: Process: Polyurethane Foam Manufacturing Regulated Substances: 80:20 TDI (Toluene Diisocyanate) Description: TDI is one of the main chemical components used in a batch reactor to make prepolymer. TDI is therefore stored in an onsight storage tank. Equipment Name----------------Capacity(lb)--------------------Description TDI storage tank------27,000-----------------------Administrative maximum limit Reactor------------------700-------------------------TDI reacted to form prepolymer TDI lines------------------25--------------------------Estimated capacity Product containers-----625-------------------------7 full containers at 3 wt% TDI Mixhead/lines-------------9--------------------------Prepolymer in mix equipment. 3 wt% TDI Conveyor-----------------0--------------------------Contains only foam Operating Modes: Name------------Eliminate--------------Explanation Normal-------------no-------------------Maximum TDI quantity present after unload of Tank Truck Threshold Quantity Calculations Worksheet: Process: Polyurethane Foam Manufacturing. Threshold Quantity: 10,000 lbs Operating Mode: Normal Total Quantity: 28,359 lbs Substance: 80:20 TDI Covered: yes Equipment--Capacity(lb)-Max. Quantity(lb)-Conc. wt%-Applicable Quan.(lb)-Comment TDI storage Tank-40,000----27,000-------------100-----------27,000------------Administrative quantity control Reactor----------700----------700----------------100-------------700 TDI lines----------25------------25----------------100--------------25 Product containers-20,800--20,800-----------3 wt%----------625---- ----3 wt% prepolymer in 7 full containers Mixhead/lines---300----------300---------------3 wt%------------9------------3 wt% prepolymer in mixhead/lines Total Quantity:28,359 Worst-case Release Scenario Description Worksheet: Scenario: Rupture TDI storage tank Description: The main tank used for TDI storage, rupture of the TDI storage tank, releasing the entire contents of the tank into a diked area. Release------------------------Diked Area--------------Pool Size--------------------Endpoint Distance Vessel: TDI tank-------------Area: 632 ft2-----------Apool: 632 ft2-------------Topography: rural Operating Mode: normal----Height: 2 ft--------------ATDI: 632 ft2--------------Temperature: 90F Substance: TDI--------------Qdike: 95,811----------------------------------------- Distance: 198 Quantity: 27,000 lbs Concentration: 100% D = 179 ft + ((632-500)/1000-500) * (251-179) =198 ft Scenari o Description: Product containers, rupture of all 7-2000 lb prepolymer storage tanks (3 wt% TDI) Release-------------------------Diked Area-----------------Pool Size--------------------Endpoint Distance Vessel: Totes -----------------Area: NA-------------------Apool: 250 ft2-------------Topography: Rural Operating Mode: Normal------Height: NA-------------------ATDI: 250 ft2--------------Temperature: 95F Substance: Prepolymer-------Qdike: NA-------------------------------------------------Distance: 144 ft Quantity: 7-2000 lbs Concentration:3 wt% D = 88ft + (95F-78F)/(100F-78F) * (160ft-88ft) = 144 ft. |