Document 488dY4dQkGJK0vDYpdooezzp

(conoco) Interoffice Communication To "OSHA - Engineering and Work Controls Plan" File From W. F. Revelt Date April, 1977 Subject UPDATE OF ENGINEERING AND WORK PRACTICE CONTROLS PLAN Attached is an update of this Plant's engineering and work practice controls plan for complying with the OSHA VCM Exposure Standard. This update is in the form of a Status Report keyed to the exposure sources listed in the April, 1975, plan (copy attached). All work practice controls have been implemented and significant progress has been made on most of the engineering controls. Currently, however, we are having to rely on breathing air to limit the VCM exposure from some exposure sources. WILLIAM F. REVELT Process Engineer CONOCO Chemicals Oklahoma City Chemical Plant APPROVED: RALPH T. FERRELL Plant Manager CONOCO Chemicals Oklahoma City Chemical Plant WFR-spt Attachment CC: (RTF-File), AWS, DEM, RAF, JAW CCR 0000i05l6 STATUS REPORT - APRIL, 1977 UPDATE OF ENGINEERING AND WORK CONTROLS PLAN FOR COMPLIANCE WITH OSHA VCM EXPOSURE STANDARD CONOCO CHEMICALS OKLAHOMA CITY CHEMICAL PLANT EXPOSURE SOURCE 1. Residual monomer in slurry and resin. 2. Obtaining and handling samples. I nr> x> STATUS 1. All batches are routinely being steam stripped. The stripping operation has reduced VCM residual in the slurry to such a low level that it was possible to deregulate the dryer building. In addition, the Plant is air purging the slurry blend tanks to further reduce the VCM in the dryer feed. 2. a. After evaluation of current sampling programs, our existing lab hood space was found to be adequate. b. Work practice controls have essentially eliminated worker exposure from this source. Several preliminary designs for a closed reactor sampling system have been prepared and currently one is being field tested. c. The advent of steam stripping of all reactor batches and air purging of the slurry blend tanks has virtually eliminated dryer line sampling exposure problems. rs o *ooo -Nl EXPOSURE SOURCE 3. VCM railcar unloading. 4. Chem wash screener. 5. Reactor rinse after dump. 6. M-500 dryer exhaust. 7. *A11 rotary seals, flexible hoses, pipe unions, and flanges, valve steins and swivel joints which are in low or high concentration VCM service. STATUS 3. Work practice controls are essentially eliminating employee exposure to VCM from this source. In addition, a process design to significantly reduce VCM releases when uncoupling railcars has been completed and mechanical design work is currently underway. 4. Steam stripping has significantly reduced exposure resulting from this source. A test run to develop a "clean wall" formula which will eliminate the need for the chem wash screener is currently under way. 5. The initial rinse is now going to the sewer. This is done to minimize VCM at the slurry dump screener since the dump screener has a higher potential for VCM exposure. 6. Steam stripping has lowered the total VCM to the dryers by such a great amount that revisions to the exhaust stacks are not necessary. 7. Due to problems with the fixed point monitor systems, the Plant has recently signed a maintenance/training agreement with the manufacturer. Also, plans are underway to relocate the fixed point monitor which was freed when the dryer room was deregulated. This should increase our capability to locate VCM leaks. *The frequency of the extensive leak check has been reduced, This is due o to finding few and small leaks during previous checks. EXPOSURE SOURCE 8. Opening and working on equipment or piping which may contain VCM in low or high concentration. STATUS 8. Specified work practices are being followed. Electropolished internals have been installed in all reactors. Steam stripping also seems to be keeping the reactor cleaner thus further lowering the cleaning frequency. In addition, continuous flushes of the reactor chem wash spray nozzles have been installed to reduce plugging problems, and new spray nozzles are being tried to make the chem wash system more effective. Also, a system to inject hydroquinone will be installed to reduce fouling of the recovery system. oo 73 HOooO* o 'C jpSURB SOURCE Residual monomer in slurry and resin. 7oo3 O o o o Vfo\JI o ENGINEERING AND WORK PRACT E CONTROLS PLAN FOR COMPLIANCE WITH OSHA VCM EXPOSURE STANDARD CONOCO CHEMICALS '.OKLAHOMA CITY CHEMICAL PLANT April, 1975 WORK PRACTICE CONTROLS ' 3- - ENGINEERING CONTROLS 1. Design and install equipment re quired for steam stripping the slurry. Essentially all processing equipment downstream of the poly merization reactors is designed for atmospheric pressure and there fore open to'the atmosphere. Processing slurry or resin in this equipment causes the emission of unreacted VCM which can lead to exposures above lppm. Plant tests have shown that steam stripping before dumping to the blend tanks substantially reduces the concen tration -of VCM in the slurry.. Thus, the amount of VCM available for emission from the open proc essing equipment will be greatly reduced by steam stripping and exposure problems will be minimized. In particular, exposures at the dump screener, chemical wash screenerv blend tanks, centrifuges, dryers, resin screeners and resin loading areas will be decreased and residual VCM in resin product leaving the plant will be decreased. i jXPOSURE SOWCE ( Obtaining and handling samples. ,, VCM rail car unloading o n 73 OOOO o ro WORK PRACTICE CONTROLS 2. Wear personnel protection equipment wich meets OSHA standards when sampling reactors, slurry, wet cake, . ' :or resin. 3. Wear personnel protection equipment which meets OSHA standards while at the un- . loading rack during car hook up and disconnect. ENGINEERING CONTROLS 2. a) install a new laboratory hood to provide more work and storage space., for slurry-and reactor samples. b) Prepare an engineering design for a closed reactor sampling system. Samples obtained during the early part of reaction contain high concentrations of VCM. By enclosing the reactor sampling system, exposure in the reactor area will be decreased because VCM will not be emitted from the sample in the working area. c) Prepare an engineering design for an improved resin sampling system at the M-50'0 dryer. 3. Prepare an engineering design to install glasses in unloading lines and rearrange valving at the un loading racks. Installation of sight -glasses will eliminate venting to the atmosphere when determining liquid to vapor transition _ at the end of un loading. Rearrangement of valving will minimize the volume vented during disconnect. jyPOSURE SOURCE WORK PRACTICE CONTROLS ENGINEERING CONTROLS Chemical wash screener. 4. Design and install an enclosure and vent system.for the chemical wash screener similar to the system on the dump screener. Reactor rinse after dump * 5. Transfer the effluent from the initial water rinse after reactor dump to the dump system and eliminate transfer to the sewer. M-500 dryer exhaust. 6. Prepare an engineering design to elevate the stack for the M-500 dryer exhaust. Currently, M-500 exhausts at the loading rack level which leads to exposure problems under certain wind conditions. Stack elevation will eliminate this problem. 3 All rotary seals, flexible hoses, pipe unions and flanges, valve stems and swivel joints which are in low or high concentration VCM service. n n o hooooUl fISs)j 7. At least once per month, measure VCM concentrations at all hoses, flanges, unions, seals, valve .stems and swivel joints in low or high concen tration VCM service. Repair or replace leakers on-the-spot, where necessary. List other leakers for repair or replace ment on the maintenance schedule. The fixed point monitor will detect the occurrence of relatively large leaks which will be attended immediately. * POSURE SOURCE ;Opening and working on equipment or piping which may contain VCM in low or high concentrations. WORK PRACTICE CONTROLS ENGINEERING CONTROLS 8. a) Before opening, remove 8. Install electropolished internals VCM from, equipment or in all reactors. Plant experience piping to the lowest has shown that the frequency of practical level by flushing, reactor entries for cleaning is purging and/or evacuation, decreased when electropolished where possible0 internals are used. This is due to a decrease in polymer build b) Wear personnel protection up on electropolished internals equipment which meets OSHA as compared to the build-up on standards when opening equip other internals. The plant has ment or piping which may five sets of internals. Two sets contain VCM. are electropolished and installed. c) Before commencing repair work, One set is at the shop for measure the VCM concentration electropolishing. The other two in or near opened equipment sets will be electropolished or piping to determine what when they can be switched out. protective equipment is required and if further VCM removal should be attempted. ro> X) o r\j u>