Document qaVebqvbMgXJ4eMDrXR6X1NVq

CHLOR - ALKALI 2 1994 REACTIVE CHEMICALS REVIEW CHLORINE AREA DO A 029570 CONFIDENTIAL POWER & UTILITIES i POTENTIAL PROBLEMS PREVENTIVE MEASURES POSSIBLE EXPLOSION/FIRE DUE TO METHANE - OXYGEN MIXTURE IN PIPE OR VESSEL POSSIBLE EXPLOSION/FIRE DUE TO METHANE - OXYGEN MIXTURE IN GAS TURBINE DURING STARTUP OR SHUTDOWN 1 - Established procedures on purging fuel gas lines with nitrogen before taking out of service or returning to fuel gas service. 1 - Double block & bleed system integrated with startup and shutdown sequence. 2 - Compressor discharge press switch to insure adequate air supply before injecting fuel gas. 3 - Flame monitors to detect presence of flame in combustion section. Trips unit if flame not detected. 4 - Manual Air solenoid with time out function to enable fuel gas valves only during startup operation. POSSIBLE EXPLOSION/FIRE DUE TO HYDROGEN - OXYGEN MIXTURE IN FILL SYSTEM AND COOLING SYSTEM FOR GENERATORS 1 - Procedure for connecting/disconnecting hydrogen trailers from Air Products. 2 - Sampling procedure to verify H2 purity. 3 - Purge procedures for pressuring/depressuring generators. POSSIBLE EXPLOSION/FIRE DUE TO HYDROGEN FROM SEAL OIL SYSTEM ENTERING INTO LUBE OIL SUMP 1 - Seal oil system is backed up by the gas turbine oil pumps. 2 - Hydrogen vapor extractor removes H2 gas before oil reaches lube oil sump. System is protected by a dip leg to prevent gas from entering sump. 3 - Lube oil reservoir has a blower to remove hydrogen gas/oil vapor from sump. J Dow Confidential 09/27/94 00 A 029571 CONFIDENTIAL POWER & UTILITIES ( \ POTENTIAL PROBLEMS PREVENTIVE MEASURES FIRE INSIDE LINES CAUSED BY RESTRICTION OF AIR FLOW DUE TO OIL IN COOLING AIR SYSTEM 1 - Seal air system has low pressure alarm to prevent oil leakage. 2 - Cooling air flow indication with high/low temperature alarms. 3 - Auto swap on plant air to seals for startup and shutdown. ) Dow Confidential 09/27/94 DO A 029572 CONFIDENTIAL. POWER AREA CRITICAL INSTRUMENTS * Compressor discharge pressure transmitter - Initiates ignition at pressures greater than 18" water. Over-speed trip diaphragm pressure switch monitors position of over-speed trip valve and is a permissive for the fuel gas over-speed trip valve. Trip is set at 35 psi. High fuel gas pressure transmitter will trip turbine at 215 psi, provided 100 % speed has not been reached. Low fuel gas pressure transmitter will trip turbine at 110 psi, provided the operator selector switch is not in SPIN position. Starting valve reset is a permissive for the turbine ignition sequence. High turbine exhaust blade bath temperature transmitters trip turbine at 1010 F. Both transmitters must be greater than setpoint to trip turbine. High turbine exhaust blade manifold temperature transmitters trip turbine at 1010 F. Both transmitters must be greater than setpoint to trip turbine. High disc cavity temperature transmitters trip generator at 550 F for first set and 800 F for remaining sets. It takes both transmitters in each set to trip the generator. J Dow Confidential 09/27/94 &0 A 0,?9<57-i c^idfntiai'. CDC AREA POTENTIAL PROBLEMS TITANIUM IN THE PRESENCE OF DRY CL2 WILL BURN. BOTH CL2 EXCHANGERS, E-201 AND E-202, CONTAIN TITANIUM TUBES. WET CL2 REACTS WITH STEEL IN A VERY CORROSIVE MANNER. WEAK H2SO4 IS VERY CORROSIVE WHEN CONTACTED WITH STEEL. PREVENTIVE MEASURES 1 - Exchangers are in wet CI2 service. 2 - Water is continually sprayed into the CI2 side of both of these exchangers. This flow is monitored and alarmed. 3 - Titanium parts in security storage. 1 - All piping in wet C12 service is of lined pipe material. 2 - All vessels in wet C12 service are fiberglass. 3 - Mist eliminating elements in D-209 A are fiberglass. 1 - The first drying tower, T-201, is a fiberglass vessel, with PVC trays. 2 - Acid strengths / flows / temperature are monitored in both drying towers. 3 - Tray temperatures are monitored in both towers. CDC.DOC Dow Confidential DO A 029574 CONF roFNTlA14 10/06/94 /` V CDC AREA POTENTIAL PROBLEMS CL2 - IRON REACTION AT COMPRESSOR C-201 A / B. CL2 ' IRON REACTION IN PIPING. CL2 - LUBE OIL REACTION. CL2 - ORGANIC CHEMICAL REACTION. PREVENTIVE MEASURES 1 - Interstage coolers to keep CI2 temperature down. 2 - High temperature trip on the compressor. Triple redundant temperatures on 2nc* and 3rd stages. Trips on two thermocouples at 325 F on 2d or 3rd stage. 3 - Deluge system. 4 - Interstage and discharge temperatures alarmed and monitored. 5 - Moisture monitored and alarmed off of discharge. 1 - No steam tracing - only electrical. 2 - Drying procedures prior to startup. 1 - Bearing housing separated from compressor seals. 2 - N2 purge on compressor seals; air purge on bearing housing. 1 - Prohibit use of hydrocarbon based compounds inside Cl2 vessels and piping. 2 - Use Fluorolube as gasket lubricant and DP cell fill fluid. 3 - Use only water or steam for cleaning of equipment used in Cl2 service. CDC.DOC Dow Confidential CDOONFAIDENTIAL 10/06/94 PURIFICATION AREA POTENTIAL PROBLEMS NITROGEN TRICHLORIDE EXPLOSION IN TAFFY POT. PREVENTIVE.MEASURES - Monitor and alarm temperature in each pot (redundant). 2 - Alarm rate of temperature rise in pots. 3 - Analyze Brine for NH3 content bi-monthly (R&D). 4 - Analyze Taffy bi-weekly for NCI3. 5 - Monitor and alarm pressure on each pot (redundant). 6 - Lowered PSV setting to 150# to catch pot overpressure. 7 . Maintain 80 PPM hypochlorite in the Brine. ; 8 - Maintain level below 40% to allow room for diluent should a reaction take place. 9 - Capability to automatically add liquid chlorine to the Taffy Pot in the event of a reaction. Also have capability to add CCI4 to pots. 10- Reboiler temperature controlled to decompose NCI3. Given 40 PSIG operating pressure, reboiler temperature set point is set at 170 F, over 30 degrees below the boiling point of the dilutant, CCI4. 11- Pressure transmitter and an alarm for high pressure "rate of rise" on transfer line. PURIF.DOC Dow Confidential 10/03/94 PURIFICATION AREA POTENTIAL PROBLEMS ORGANIC IMPURITIES; WET CCI4 CHLORINE - ORGANIC CHEMICAL REACTION. PREVENTIVE MEASURES 1 - CCI4 provided by Solvents from "check tank". Check tank analysis to be obtained for each load. 2 - In plant capability to analyze each load for organics and H2O. 3 - Dedicated line from Solvent. 1 * Prohibit use of hydrocarbon based compounds inside CI2 vessels and piping. 2 - Use fluorolube as gasket lubricant and DP cell fill fluid. 3 - Use only water or steam for cleaning of equipment used in CI2 service. PURIF.DOC Dow ConfidentiiJ DO A 029577 CONFIDFNTIAL 10/03/94 LIQUEFACTION AREA POTENTIAL PROBLEMS HYDROGEN - CHLORINE EXPLOSION IN TAIL GAS WATER/MOIST AIR ENTERING LIQUEFACTION PROCESS FROM BRINE SCRUBBER CREATING SEVERE CORROSION PROBLEM CHLORINE - IRON FIRE FROM LIQUID CL2 PUMPS OVERHEATING HIGH MOISTURE CONTENT IN CL2 CAUSING ACCELERATED CORROSION TO CARBON STEEL H20 IMPURITIES ADMITTED TO PROCESS VIA FREON PREVENTIVE MEASURES 1 - Monitor hydrogen in cell continuously. 2 - Redundant hydrogen analyzers monitor and alarm tail gas to Brine Scrubber (set point - 3.5% H2 in inerts) analyzers included on critical instrument program ; Generator runback: 4.75%. 3 - Automatic N2 dilution into tail gas. Control at 2.4%. 1 - Check valve installation on tail gas line to scrubber. 2 - High pressure alarm on Brine Scrubber. 3 - Moisture analyzer and alarm on T-505 tail gas inlet line. 4 - Liquefaction startup and shutdown procedures, on computer, call for blinding the liquefaction process from the brine scrubber when liquefaction is to be depressured. 1 - Alarm on low cooling flow. 2 - Minimum flow lines provided to prevent dead-heading. 1 - Redundant moisture analyzers monitored and alarmed. 1 - Complete analysis on all freon shipments. DO Dow Confidential 07/17/92 LIQUEFACTION AREA POTENTIAL PROBLEMS CL2 LEAK INTO R-12 REFRIGERATION SYSTEM (C-520 LEADING TO REACTION WITH COMPRESSOR OIL) . PREVENTIVE MEASURES 1 - Analyzer monitors and alarms CI2 in freon. This analyzer and alarm scheme is includec in the critical instrument program. 2 CI2 - R-12 exchangers have double tube sheets. Dow Confidential Oo Ops'r9, c - IAi 07/17/92 EVAPORATION AREA POTENTIAL PROBLEMS PREVENTIVE MEASURES NCL3 ACCUMULATION IN EVAPORATOR BOTTOMS 1 - Flush evaporator bottoms once daily to T-204. HIGH PURITY GAS CONDENSING IN USER HEADER H2O / IMPURITIES ADMITTED TO PROCESS VIA FREON I - Redundant temperature transmitters. . 2 - Superheater on`R-11 system which operate: independently of freon compressor. 3 - Computer monitoring of CI2 gas header pressure and temp to calculate dewpoint. Scam alarm when gas is 10 F from dewpoint. 4 - Electric heat tracing and good insulation on gas header to CI2 plant. Heat tracing designed to maintain 100 F heater temperature. 1 - Complete analysis on all freon shipments. Dow Confidential 07/17/92 CHLORINE AREA CRITICAL INSTRUMENTS Chlorine EBV Mod 5 self test ( Not a critical instrument check) Liquid chlorine transfer line AOVs Hydrogen inerts analyzer - run back at 4.5 % Freon in chlorine analyzers (liquid and gas) - 10 PPM alarm Chlorine in Freon alarm (switch) ' Taffy pot temperature - high temperature alarm at 150 F Chlorine Compressor Chlorine compressor discharge valve Chlorine compressor discharge pressure Cell header pressure control flow Flow vs. valve position for chlorine to J-252 Chlorine compressor runback functions C-201 generator trips Chlorine compressor trip permissives INST.DOC Dow Confidential' OO A CONfrlDFNTl 10/03/94 > CHLORINE AREA TRIPS / RUNBACKS Generator High hydrogen in tail gas (runback) Low cell head level (4 inches) Cell header "mega" back pressure Chlorine Compressor High interstage temperature - 325 F Cell header vacuum reaches -9.5 inches water instantaneously Cell header vacuum reaches -8.0 inches water and holds for ten seconds Cell header vacuum reaches -8.0 inches water twice in 2 minutes INST.DOC Dow Confidential DO A 029582 CONFTDFNTTA1. 10/03/94