In Situ Recycling of Cleaning and Rinsing Fluids to Meet Lean and Green Cleaning Process Targets By Steve Stach The Science of Cleaning Green
Outline Setting recycling targets? Paying for recycling? What can be recycled? Review of the 4 basic types of fluid recycling Absorption Distillation Filtration Replenishment Estimating the cost and saving Estimating system life Cost Model review
Setting Cleaner Recycling Targets Government Regulations Few direct mandates Significant cost/liability regarding waste; i.e. generation, storage, transportation, disposal Corporate Directives Avoid liability by not generating Cut manufacturing expenses Marketing
Potential Savings Water Saving up to 99% reduction Chemical Savings 50-99% reduction Energy Saving 10-50% reduction Waste Disposal 50-90% reduction
What Cleaning Fluids Can be Recycled? Just about everything! Water Tap, DI Water Mixtures, Neutral ph Buffered aqueous mixtures Water Mixtures, Alkaline Emulsions, Homogenous mixtures Organic, nonflammable Halogenated solvents Organic, combustible Glycols, oils, esters Organic, Flammable Alcohols, light hydrocarbons
Choosing the Right Recycling Technology 1. It depends on the Solvent 2. It depends on what is happening in the solvent? Alkaline/Saponifier Water/Emulsion Organic Solvent Reacting w/soils Accumulating Soils Evaporation
Getting Started Look at your Mass Balance Mass Balance analysis looks at all materials entering and leaving the cleaning process. Shows where you are loosing or gaining fluids/ingredients
Cleaning Mass Balance Diagram Fluid Feed, Make-up Parts Mist-Evaporative And Drag-Out Losses w/soils Recycling System Waste Fluid Tank Cleaning System Cleaning Fluid With Soils Sewer or Disposal
Identify & Understand Your Recycling Method Recycle Method Type Used with Waste stream Waste disposal handler Chemical addition Ion Exchange Carbon Adsorption Zeolite Absorption Chelation Distillation Filtration Reverse Osmosis Additive Key Ingredient Subtractive Adsorption Subtractive Adsorption Subtractive Adsorption Subtractive Adsorption Subtractive Distillation Subtractive Filtration Subtractive Filtration 1) Reactive Aqueous Mixtures (saponifiers) Rinse water Alcohols Glycols Esters Rinse water NPB CFC s HCFC s Water with heavy metals NPB CFC s HCFC s All fluids Rinse water Soil loaded tank dump Depleted DI resins Carbon media with organics Zeolite with adsorbed contaminate Chelation media with heavy metals Non volatile residues Filters with contaminate Reject fluid stream System Complexity level Company Technician Medium Third party Operator Low Third party Operator Low Third party Operator Low Third party Operator Low Company Technician High Company Technician Medium Company Technician Medium Safety concern
Cleaning Fluid Recycling Choices Cleaning/Rinsing Agent Adsorption Distillation Filtration Replenish Ingredient Water Only Recommend Not Used Used Not Used Water Neutral Not Used Not Used Used Recommend H2O IPA Water Alkaline Not Used Not Used Used Recommend Organic Non-flammable Used Recommend Used Not Used NPB Cool Prec. Organic Combustible Recommend Used Used Not Used Organic Flammable Recommend Used Used Not Used
Additive Recycling Technologies Key Ingredient Replacement Common in aqueous mixture to replace drag out or reactive losses Saponifing agents Degreasing stabilizers
Subtractive Recycling Technologies Filtration Use of filters to remove soils Distillation Removes contaminates with higher boiling points Absorption Use of Carbon, DI resins, Zeolites and other Media to Adsorb contaminates
Fluid Filtration One of the oldest recycling methods Configuration Cartridge, Bag, Plate, Cake Filter Size 1to10 micron typical Design Type Mono or Multi-Filament Absolute vs Standard Recommended uses Used in most closed or open loop cleaning systems
Fluid Distillation Boiling fluid is vaporized and condensed High boiling soils are left behind for disposal Recommended for non-flammable, single solvents or azeotropic solvent blends Not usually recommended for water or flammable solvents
Ion Exchange Ionic soils are captured by ion exchange resins Cations (Na +, K +,NH 3+ ) are removed by cationic exchange resins Anions (OA -, Br -,CO 3- ) are removed by anionic exchange resins Mixed Beds remove both Anions and Cations Recommended for purifying water and most organic solvents Not recommended for solutions containing amines
Organic soils are captured by Granular Activated Carbon (GAC) Works on basis that Like attracts Like Capacity depends on the molecule Carbon Absorption Often used in conjunction with DI closed loop systems
GAC is made by anaerobic heating organic material to drive off all volatiles Carbon Absorption Most GAC is acid washed to remove acid soluble impurities Coconut shell and anthracite coal are two type that product low powdering GAC can be partially regenerated by steam stripping not recommended
Carbon Absorption VS Compound Compound Mole Weight Water Solubility % Adsorption g soil/ g GAC 2-ethyl butanol 102.2 0.43.170 85.5% Mono-ethanol amine Di-ethanol amine 61.1.015 7.2% 105.1 95.4.057 27.5% Nitro-benzene 123.1 0.19.196 95.6% Butyric acid 88.1.119 59.5% Adsorption % reduction Ethylene glycol mono butyl ether 118.2 0.112 55.9% Test solution1g/liter
Closed Loop Inline Cleaning System GAC Carbon Mixed FilterMΏ Turbine 1g/m 1g/m
Reverse Osmosis (RO) RO is most commonly used for feed water generation to closed loop cleaners RO typical removed ~90% of dissolved solids from tap water
Reverse Osmosis Molecular sized microscopic pores block large molecules and allow smaller molecules to pass
Incoming Tap/RO water Feed to fill tanks Initial and Make-up Operational.Flow @120F= 3gal/hr estimated Dryer DI Rinse Power Rinse Chem Isolation Wash Chem pump High Alarm High Alarm GAC Carbon Mixed Filter MΏ Turbine Add Add Low Alarm Low Alarm ~25gallons 1g/m 1g/m ~40gallons Gravity Drain
Problem Heavy Metals in DI/GAC media Absorptive medias capture metal ions Cations (Pb +2, Ag +2,Cu +2 ) are captured by cationic exchange resins GAC can do the same Use new GAC and DI media or find regenerator with metal cheatlation system
Molecular Sieve Absorption A molecular sieve traps molecular soils in microscopic pores. Naturally occurring materials are referred to as zeolites Man made materials are called molecular sieve. Molecular sieve comes in different pore sizes ranging from 3 to 12 angstrom Commonly used as a desiccant Available in round or extruded pellets
Molecular Sieve Absorption Useful in removing water, flux residues, and most ions from organic cleaning solvents 35X 700X 4,500X
Use of Molecular Sieve Molecular Sieve filters to remove contamination from Degreasing Solvents Organic solvents
The Impact of the Recycling Location
The Impact of the Recycling Location Here, There or Anywhere? GAC Filter MΏ Mixed Turbine Carbon Chem pump ~25gallons 1g/m1g/m In Situ (in the cleaner) Plant System (in the factory) Third party (bonded & licensed)
Off-site Treatment of Cleaning Materials The Local Sewer Plant Check with local water authorities A permit may be requires The DI Guy What materials do they use? Source, new or regenerated? How do they dispose of the waste? Solvent Recycler/Disposal Use EPA licensed & bonded company Cradle to grave responsibility
In-plant Recycling of Cleaning Fluids Distillation and Evaporation Check with local air quality authorities A permit may be required Central DI Plant What materials are use? Source, new or regenerated?
In Situ Recycling of Cleaning Fluids Built in, or Next to the Cleaner No transfer logistics Minimizes heat loss Fewer Parts Local Control Requires training Operator Maintenance Costs less to Operate Equipment costs less than stand alone Lowest operating costs
The Cost of Cleaning
Building the Cost Model Indep Inline Cleaner Cost Model Process Data Inline Open Loop Closed Loop Central System In Situ Closed Loop Varib Equipment cost $200,000 $200,000 $200,000 DI system system cost $25,000 $35,000 $5,000 Shipping $5,000 $5,000 $4,000 Water consumption rate gph (operating) 300 10 10 Cost of water $'s/gal $0.01 $0.01 $0.01 Cost to regenerate DI (1.5Ft3) $300.00 $500.00 $500.00 Water purity (dissolved solids) mg/gal 250 20 20 Final rinse rate GPM 5 5 5 Power cost $s/khr $0.10 $0.10 $0.10 Operating KW (KV*A) 100 110 75 7 year equipment amortization 6 Run time per Shift 300 Shifts per year Process Costs ($'s/hr) Absorbtive capacity (mg CaCO3 or Succinate)?????????????????????????? Bed Life (hrs of operation)
Capacity of Close Loop Absorptive Beds Depends on the Ion Molecular weight & valance Tank Absorptive Capacity (Ab total ) Bed Volume (V ab ) Absorptive Capacity (Ab cap ) (Ab total ) = (Ab cap ) X (V ab )
Estimating the Life of Absorptive Beds Contamination Feed Rate Mass Flow Rate (MF rate ) Bed life = (Ab total / MF rate )x % factor * * % factor is % available in beginning + % remaining at exhaustion US map showing water hardness
Building the Cost Model Indep Inline Cleaner Cost Model Process Data Inline Open Loop Closed Loop Central System In Situ Closed Loop Varib Equipment cost $200,000 $200,000 $200,000 DI system system cost $25,000 $35,000 $5,000 Shipping $5,000 $5,000 $4,000 Water consumption rate gph (operating) 300 10 10 Cost of water $'s/gal $0.01 $0.01 $0.01 Cost to regenerate DI (1.5Ft3) $300.00 $500.00 $500.00 Water purity (dissolved solids) mg/gal 250 20 20 Final rinse rate GPM 5 5 5 Power cost $s/khr $0.10 $0.10 $0.10 Operating KW (KV*A) 100 110 75 7 year equipment amortization 6 Run time per Shift 300 Shifts per year Process Costs ($'s/hr) Absorbtive capacity (mg CaCO3 or Succinate) 1,680,000 7,900,000 7,900,000 Bed Life (hrs of operation) 3.7 219.4 219.4
Cleaning Cost Estimates Inline Open Loop Closed Loop Central System In Situ Closed Loop Annual Cost of beds OL DI, CL DI+GAC $144,642.86 $4,101.27 $4,101.27 Hourly Cost of beds $80.36 $2.28 $2.28 Hourly cost of tap water $3.00 $0.10 $0.10 Power costs/hr $15.00 $16.50 $11.25 Total Power and water cost $/hr $98.36 $18.88 $13.63 Equipment Amortization cost per hr $16.43 $17.14 $14.93 Total Equipment + Water + Power ($/hr) $114.79 $36.02 $28.56
Summary Government and industry are driving recycling Cost and environmental benefits provide the rewards for conversion Cleaning mass balance analysis provides data to start
Summary All cleaning solvents can be recycled There are many methods of recycling Your clean solvent guides you recycling method
Summary Recycling reduces process costs The location of the recycling system can affect cost. In situ recycling is the most cost effective
Conclusions If you are not recycling your cleaning fluids, you should be!
In Situ Recycling of Cleaning and Rinsing Fluids to Meet Lean and Green Cleaning Process Targets by Steve Stach