By: Brent Hardman, P.E. 740 E. Monroe Road, St. Louis, MI High Strength Low Salt Hypo (HSLS Hypo) Improved Hypo Quality and Production

What is High Strength Low Salt Hypo? 30% by wt. NaOCl with 8.5% by wt. NaCl 13% by wt. NaOCl with 3.7% by wt. NaCl 6% by wt. NaOCl with 1.7% by wt. NaCl Traditional Hypo: 13% by wt. NaOCl with 10.4% by wt. NaCl 6% by wt. NaOCl with 4.7% by wt. NaCl

HSLS Hypo Process Diagram Powell HSLS Hypo Generator Powell HSLS Hypo Salt Removal Cl 2 50% Caustic 30% HSLS Hypo Salt GPL Av. Cl 2

HSLS Hypo Solution

Salt Removal System

Traditional Hypo vs. HSLS Hypo Traditional Hypo HSLS Hypo NaOClNaClSG NaOClNaClSG Wt. % 30.0%XX 8.5% %XX 7.1% %XX 5.7% %13.0% %4.7% %11.9% %4.3% %10.4% %3.7% %8.3% %3.0% %6.3% %2.3% %4.7% %1.7% %2.4% %0.9%1.0376

Chemistry Advantages Reduction in Ionic strength of the solution: ◦ Slower decomposition resulting in a longer half-life ◦ Less chlorate ion formation ◦ Less perchlorate ion formation ◦ Less oxygen formation

Decomposition

Chlorate Formation

Perchlorate Formation

Oxygen Formation

What are the Production Advantages? Reduced chlorine and caustic consumption per gallon produced Recovery of salt for raw material savings Improved stability and reduced weight allow more flexibility of logistics ◦ Lower specific gravity will reduced the overall weight load for shipment of same volume ◦ Increased volume per shipment for same load weight

Chlorine and Caustic for HSLS Hypo With lower decomposition rates, diluted HSLS hypo can be shipped at a lower strength than traditional hypo. Assuming a storage time of 3 days to ship no less than 12.0% Traditional Hypo is typically manufactured at 13.0%. HSLS Hypo could be diluted to 12.6%. Difference accounts for 3.0% savings in raw materials.

Reduced Shipping Strength

Salt Savings for HSLS Hypo Approximately 3,300-3,600 lbs. of NaCl consumed to produce 2,000 lbs. of chlorine 2,000 lbs. of chlorine reacted to 30% NaOCl = 1230 lbs. of NaCl savings by reclaiming salt 1230 lbs. of reclaimed salt = 34-37% needed for original electrolysis Reclaimed salt is very pure; if returned back to chlor- alkali plant only requires secondary brine treatment

Salt Purity Element / Compound mg/kg NaCl99.85% Insolubles<0.005% Al<1.6 Ba<0.17 Ca0.39 Mg<0.3 Sr<1.6 Fe<0.03 SiO Na 2 SO 4 N/D

Storage HSLS Hypo

HSLS Hypo Shipping Advantages HSLS Hypo is stored on producers site at 50 ° F. One tank truck load (5,000 gal.) of 13.0% diluted HSLS Hypo contains 3,900 lbs. less salt than tradition hypo. 5,000 gal. tank truck load of 30% wt. equals 13,750 gallons of 13% wt. High dilution ratio allows for shipment flexibility. ◦ Shipment of 30% wt.  Economically ship 2.75 time farther  Increase total delivered volume by 2.75, diluted at distribution center or customer site ◦ Shipment of diluted product  Increased stability allows for decreased shipping strength

HSLS Hypo Shipping

HSLS Hypo Summary HSLS Hypo with lower salt concentration offers a product that is more stable and lighter. ◦ Greater stability means less sodium chlorate and perchlorate formation during decomposition. Reclaim salt to improve chlor-alkali plant efficiencies. HSLS Hypo can improve the shipment economics by: ◦ Increasing shipping radius from the plant ◦ Lighter product therefore more hypo per load

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