Cleaning Techniques for Cooling Systems and Boilers

Cleaning Techniques for Cooling Systems and Boilers

Cleaning Applications in Industrial Utility Systems Pre Operational Cleaning and Passivation Removal of Organic Buildup caused by leaks or biofilms Exchanger degreasing Removal of Scale Rust Removal and Passivation Cooling Tower Cleaning Boilers Resin andmembrane Cleaning Boil Outs Scale or Iron removal

Pre Operational Cleaning Cooling Systems Heat Exchangers Piping Boilers The process will vary based on metallurgy.

Problems Associated with Fouled Systems Corrosion by product Scale Microbiological growth Inefficient heat transfer Reduced Flow Increased Corrosion

Cleaning Reduces Operating Costs Extending equipment life Reducing unscheduled downtime Energy conservation Pump operation Heat transfer Chiller efficiency d k h l h Improved worker health and safety

Primary System Contaminants and Issues Contaminant Hardness Salts Silica Alkalinity and CO 2 Iron and Manganese Suspended Solids and Organics Oxygen Issues Scaling and Deposits Scale Scale and Corrosion Deposition Deposition and Microbiological Food Source Corrosion

Typical Root Causes Water source Contaminants t in makeup water Corrosive water System leaks Poor or no filtration System chemistry Lack of treatment Poor control Corrosion Microbiological Under deposit Stagnant conditions Process leaks Gadgets Air borne contaminanants

Before You Clean Determine the cost of the dirty condition and the value of the cleaning Determine the type of deposit to be cleaned and the system metallurgy Determine spent cleaning solution disposal limitations and potential hazards Decide on a cleaning process and document procedure

Cleaning Process Follow thedocumented cleaning procedure, in detail with site specific instructions Monitor the cleaning Follow disposal guidelines Inspect thesystems and document efficacy Restore normal operation by flushing or drain and fill Verify and document results.

Preoperational Cleaning Non Galvanized Cooling Systems Use ChemTreat CT 30 at 5 gallons per 1000 Galvanized Towers We recommend surfactant with a stabilized phosphate program at 20 ppm of ortho for the first 24 48 hours at ph 7 7.8. See Technical Bulletin 82. Stainless Food Equipment SS16/SS16F with CL427 Carbon Steel Equipment CT38

SS16 Cleaning of Stainless Retort

CN230 Cleaning of Rotary Cookers and Cleaning removes eslight mineral scale, silica, magnesium silicate and rust. Removes organics, can coatings andbiofilms biofilms. Operate at 180 F for 3 hours. Phosphate free version is in development as CN232 Boilers

Boiler Boil outs For an improved process use the neutral ph process at low fire, < 180 F. This process will remove oil and grease, light mill scale and flash rust as well as pacify the boiler.

Boiler Cleaning Preoperational cleaning using CT38 or CT23 Iron cleaning and passivation using CT38 Scale Removal using CN140 followed by passivation with CT38 Scale Removal using CN230 and CN232

Neutral ph Rust Removal and Passivation ChemTreat CT 38 for smaller systems ChemTreat CL3858, BL 1240 for larger systems See Technical Bulletin 93

Factors that Impact Cleaning using this CT 38 process How dirty the system is Temperature: Increases Rate Do not exceed 140 F with acidic cleaners Do not exceed 180 F with neutral ph cleaning ph Maintain 6.5 7.2 for best results ph<6.0 increases corrosion ph>7.2 slows cleaning Cleaning rate increases with flow Maintain between 2 9 ft/sec ORP ( 50 to 600 mv) A negative ORP is critical for good results Have extra BL1240 on hand

Neutral ph Cleaning Corrosion Rates During Cleaning Copper/Admiralty 1 4 mpy without supplemental azole <0.5 mpy with supplemental azole Mild Steel 20 60 mpy Aluminum 2 mpy Galvanized 150 mpy

How Do You Know You re Done? Spool pieces are clean Flow is restored to design levels Iron level/color stabilizes ph stabilizes Iron removal has hit a maximum A multiple cleanings may be necessary in heavily fouled systems as a result of iron loading

Neutral ph Cleaning of a Mild Steel Retort

Scale Removal from Tower Fill and Heat Exchangers without Acid Cooling Towers use ChemTreat CL 401, dilute to 10 50% in a garden sprayer or use as the soap in a pressure washer. Clean long term by enhancing your current program at 80 ppm for 90 120 days

Acidic Cleaning of Cooling Towers and Chillers Long Term Use a stabilized phosphate program and control the phosphate at 15 25 ppm and the ph at 6.5. Even safe for galvanized. Short Term Keep ph between 2 3 and feed in small increments over 4 6 hours. ChemTreat CN 135 best for galvanized ChemTreat CN 140 Urea Hydrochloride for mild steel, and copper. Not safe with galvanized.

Tower Cleaning Multiple Options Surfactant and Peroxide CL457 at 05%with 0.5% antifoam or CL427 at 4000 ppm with CL450 at 200 ppm Chlorine Dioxide or CL3000 Halogen and Surfactant, CL450 or CT907

Resin Cleaning Iron Fouling use ChemTreat CL16 at 0.5 05 gallons per 10 cubic foot of resin. Biological or organic fouling use Chemtreat CT1901 at 1 quart per cubic foot of resin with air sparging. Membrane cleaning we have an entire support group for these applications i

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