Document Jrq15dKGzXrYoo4na4bzox6n6

CHLOR - ALKALI 2 1994 REACTIVE CHEMICALS REVIEW BRINE AREA 00 A 046050 CONFIDENT T At BRINE TREATING CHEMICAL REACTIONS Ca + Na2CC>3 Mg + 2 NaOH -------> -------------- ------> CaC03 + 2 Na Mg(OH)2 + 2 Na 2 NH4CI + 2 NaOCL ---------------------------- N2 + 3 NaCl + 3 H2O + ------> 2 HC1 TANNINS + NaOCl ----------------------------------> INSOLUBLE SOLIDS 2 NaOH + Cl2 -------> NaOCl + NaCl + H20 2 NaOH + C02 ------ > pH > 10 Na2C03 + H2O Dow Confidential DO A 046051 CONFTDFNTTAI 08/03/95 NOTE: As per the reactive chemical audit of 1994, the following action item response has been entered on 1-5-95. The action item # is RC-10. Follow up by Jeff Harrison. In the Brine Treating area, T-101B (Carb. Tower) utilizes the above reaction: 2 NaOH + C03 Na2C03 + HaO pH > 10 to form Sodium Carbonate. Sodium Carbonate is used in the mix tanks to treat Calcium. However, the above reaction requires a pH > 10. In the event the pH is low (7-10), the possibility exists for the following to form (Bicarbonate): OH' + C02 ------> HC03` pH 7-10 This an unwanted reaction from the standing that the efficiency of Calcium removal becomes lower. Requiring twice as much Bicarbonate than Carbonate to treat the Calcium in the mix tanks. See the following reactions: Carbonate and Calcium C03" + Ca++ ------> CaC03 Calcium and Bicarbonate 2 HC03' + Ca" ------> Ca(HC03)2 Dow Confidential DO A 04605? OONFTDFNTIAt, 08/03/95 Therefore, the undesired result is the efficiency reduction. The potential for Hydrogen gas formation in the Bicarbonate reaction is not likely. Lines of Defense To prevent the Bicarbonate from forming, the Carbonate tower runs with a pH control scheme and grab sables are analysed 3 times per shift. Dow Confidential DO A 046053 CONFTDFNTTAL 08/03/95 Reactive Chemicals CA-2 Consolidated Audit Notebook Reaction Chemistry for MDEA in Raw Brine Entering the Chlor-alkali Process The likely reaction pathways for MDEA in brine are as follows: Reaction 1 Reaction 2 Reaction 3 Reaction 4a Reaction 4b Reaction 4c CH3N(CH2 CH2OH)a + 2HOC1 -CIN(CH2 CHjOHIj + HCHO + H20 + HC1 then C1N(CH2 CH.OH), -> NH2CH2CH2OH + HCHO + HC1, then NH2CH2CH2OH + 2HOC1 NH2C1 + 2HCHO + HQ then 2NH2C1 + 2H20 N2 + 2HCI + 2HOCI + 2H+ or NH2C1 + HOC1 -> NHC12 + HzO or NH2C1+2HOC1 -> NC13 + 2H20 The selected reaction pathway from among Reactions 4a-c is highly dependent on molar ratio of hypochlorus acid to MEA and pH. High pH (>12) promotes reaction 1. Reaction 4c should be assumed for reactive chemical planning purposes, though reactions 4a-c are likely to be competing. LINES OF DEFENSE 1. Grand Bayou Operations has written agreements with the owners of the gas fractionation plant where the MDEA is stored to report significant releases of MDEA to Dow. 2. Maximum allowable quantities have been established with the owners of the gas fraction plant for on-site storage of MDEA. 3. Extreme dilution of an MDEA spill with ground water used for mining would mitigate any immediate danger from excessive nitrogen trichloride formation. 4. Raw brine is monitored for ammonia content weekly. 5. Brine mining wells can be quarantined to control or prevent processing of contaminated brine. 6. Any MDEA release large enough to have a significant impact on raw brine would trigger and environmental notification. 7. Nitrogen trichloride is monitored in the taffy pots weekly. D0 A 046054 00NF10FNTTAl BRINE AREA 09/94 DOW CONFIDENTIAL DO A 046055 CONT T DFNT T AL BRINE RAW MATERIALS BRINE: Ca Mg NaCl 350 PPM 10 PPM 300 GPL RESATURATED BRINE: NaCl NaOH 350 GPL 1-5 GPL CARBONATE: NaOH Na2C03 3-6 GPL 60 - 80 GPL HC1_l 15 - 18% Dilute from 35% with Condensate NaOH; 10% BETZ 90820 Dow Confidential 00 A 046056 O0NFTDFNTI Al. 08/03/95 BRINE PRODUCTS TREATED BRINE; Total Hardness (Ca+2) 2-5 PPM NaOH Na2 C03 NaOCl nh3 NaCl 1.5 - 4 GPL 2 - 2.5 GPL 60 -80 PPM < 1 PPM > 300 GPL CLARIFIER UNDERFLOW; h2o NaCl CaC03 Mg(OH)2 Na2C03 NaOH SOLIDS FLOC 70.5 % 23.7 % 4.8 % 0.5 % 0.2 % 0.1 % 0.1 % 0.01 % Dow Confidential 00 A 046057 conftdfnttai 08/03/95