The client's reverse osmosis system utilized coagulants, antiscalants and cleaners to produce high quality water. With the current chemicals, the reverse osmosis system was cleaned every 90 days due to scaling or deposits. Pressure drops would rise and permeate quality would be adversely affected if not cleaned within this timeframe. Click here to learn how Crown Solutions improved RO performance and run times with HydrexTM chemistries.
Case Studies
Cooling Tower High Corrosion Rates
The incumbent water treatment provider was treating their 3 cell, 25,000 gpm recirculation rate cooling system with ozone as the biocide along with an organic based scale and corrosion inhibitor. The client was getting higher than desired corrosion rates of 8 mpy on mild steel and wanted lower corrosion rates. Increasing the amount of scale and corrosion inhibitor added had not resulted in improved corrosion rates. Click here to learn how Crown solved the cooling tower high corrosion rates.
High Turbidity & Silt Density Index
The refinery was using a competitive treatment program to clarify the river water for use in the cooling towers as make-up and for reverse osmosis units that supplied high pressure boiler water make-up. The program was yielding high turbidities out of the clarification process and high SDI (Silt Density Index) to the new reverse osmosis units. This was causing frequent membrane replacement and poor overall operation of the RO facility. Crown was asked to review the site and find a solution to the turbidity and the SDI issues.
The facility had experienced several documented process leaks of lignin into their cooling water system due to failed check valves as well as some operating errors. Over time it was determined that lignin had coated the entire system and was slowly sloughing off and causing plugging in the surface condenser which lowered the operating vacuum of the system by as much as 20%. This was causing a major decrease in operating efficiency and having a huge impact on the cost of operating the system. Click here to learn how Crown worked with the client to clean up the contaminant.
Gas Scrubber Effluent Scaling Problem
Effluent from a scrubber on the process gas stream, which had an average flow rate of 35 gpm, contained high water hardness (460 ppm) and alkalinity (300 ppm) and was orginally allowed to be direct discharged to the city without any treatment. In early 2007, the city directed the client that they now had to adjust the pH of the effluent stream to between 8 - 8.5. Two issues developed as a result:
- The amount of 50% sodium hydroxide required to maintain the required effluent pH increased dramatically to approximately 170 gpd.
- Adjusting the pH caused a sever scaling issue that required routine cleaning of the piping in the facility as well as the line leading to the city system.
Crown was asked to solve the gas scrubber effluent scaling problem.
High Chemical & Blowdown Rates
The client used soft water make up on their large boiler system and was interested in reducing their operational water costs. Crown profiled the entire application and determined that replacing the older pretreatment softener sytem with a new softener and RO (Reverse Osmosis) system would allow the boiler cycles to be increased from 6.5 to well over 80 cycles (1.25% blowdown); as well as have a positive payback. Click here to learn more about the improved boiler pretreatment.
