Api dr 351 1996 scan (american petroleum institute)

~~ A P I DR*353 96 ~ ~~ ~~ O732290 0553632 T Proceedings: Workshop to Identify Promising Technologies for the Treatment of Produced Water Toxicity HEALTH AND ENVIRONMENTAL SCIENCES DEPARTMENTAL REPORT NUMBER DR351 JUNE 1996 American Petroleum Institute `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale A P I DR+35L 96 W 0732290 5 b L B T One of the most significant long-term trends affecting the future vitality of the petroleum industry is the public’s concerns about the environment Recognizingthis trend, API member companies have developed a positive, forward-looking strategy called STEP: Strategies for Today’s Environmental Partnership This program aims to address public concerns by improving our industry’s environmental, heaith and safety performance; documenting performance improvements; and communicating them to the public The foundation of STEP is the API EnvironmentalMission and Guiding EnvironmentalPrinciples API ENVIRONMENTAL MISSION AND GUIDING ENVIRONMENTAL PRINCIPLES `,,-`-`,,`,,`,`,,` - The members of the American Petroleum Institute are dedicated to continuous efforts to improve the compatibility of our operations with the environment while economically developing energy resources and supplying high quality products and services to consumers The members recognize the importance of efficiently meeting society’s needs and our responsibility to work with the public, the government, and others to develop and to use natural resources in an environmentally sound manner while protecting the health and safety of our employees and the public To meet these responsibilities, API members pledge to manage our businesses according to these principles: To recognize and to respond to community concerns about our raw materials, products and operations d, To operate our plants and facilities, and to handle our raw materials and products in a manner that protects the environment, and the safety and health of our employees and the public d, To make safety, health and environmental considerations a priority in our planning, and our development of new products and processes To advise promptly, appropriate officials, employees, customers and the public of information on significant industry-relatedsafety, health and environmental hazards, and to recommend protective measures d, To counsel customers, transporters and others in the safe use, transportation and disposal of our raw materials, products and waste materials To economically develop and produce natural resources and to conserve those resources by using energy efficiently To extend knowledge by conducting or supporting research on the safety, heaith and environmental effects of our raw materials, products, processes and waste materials To commit to reduce overall emission and waste generation To work with others to resolve problems created by handling and disposal of hazardous substances from our operations O To participate with government and others in creating responsible laws, regulations and standards to safeguard the community, workplace and environment Q To promote these principles and practices by sharing experiences and offering assistance to others who produce, handle, use, transport or dispose of similar raw materials, petroleum products and wastes Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale A P I DR*351 96 m 0732290 0553bl19 816 Proceedings: Workshop to identify Promising Technologies for the Treatment of Produced Water Toxicity Health and Environmental Sciences Departmental Report No DR351 PREPARED UNDER CONTRACT BY: PARSONS ENGINEERING SCIENCE, INC JOHNBons, PROJECT MANAGER JAMESSALISBURY, ENVIRONMENTAL SCIENTIST 10521 ROSENHAVEN STREET VIRGINIA22030 FAIRFAX, JANUARY 1995 11’ `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale American Petroleum Institute API DR*353 96 = 0732290 0553636 699 FOREWORD API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL NATURE WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE, AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED API IS NOT UNDERTAKING To MEET THE DUTIES OF EMPLOYERS, MANUFACTURERS, OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIP THEIR EMPLOYEES, AND OTHERS EXPOSED, CONCERNING HEALTH AND SAFETY RISKS AND PRECAUTIONS,NOR UNDERTAKING THEIR OBLIGATIONS UNDER LOCAL, STATE, OR FEDERAL LAWS `,,-`-`,,`,,`,`,,` - NOTHING CONTAINED IN ANY API PUBLICATION IS TO BE CONSTRUED AS GRANTING ANY RIGHT, BY IMPLICATION OR OTHERWISE, FOR THE MANUFACTURE, SALE, OR USE OF ANY METHOD, APPARATUS, OR PRODUCT COVERED BY LETTERS PATENT NEITHER SHOULD ANYTHING CONTAINED IN THE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABILITY FOR INFRINGEMENT OF L E T E R S PATENT Copyright O 1996 American Petroleum institute ii Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale A P I DR*353 9b 0732290 O553637 525 W ACKNOWLEDGMENTS THE FOLLOWING PEOPLE ARE RECOGNIZED FOR THEIR CONTRIBUTIONS OF TIME AND EXPERTISE DURING THIS STUDY AND IN THE PREPARATiON OF THIS REPORT Alexis Steen, Health and Environmental Sciences MEMBERS OF THE API W,WORK GROW Joe Smith (Chairman), Exxon Production Research Company Kris Bansal, Conoco Stanley Curtice, Texaco Philip Dom, Shell Development Company Tracy Fowler, Exxon Production Research Company Jerry Hall, Texaco Research and Design Sung-I Johnson, Phillips Petroleum Company Zara Khatib, Shell Development Company Gary Rausina, Chevron Research and Technology Company Lawrence Reitsema, Marathon Oil Company Grateful thanks are also extended to the workshop facilitator, Dr Eric Snider, P.E (Clemson University), and to the expert speakers and other workshop attendees without whose participation the workshop would not have been possible iii Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale `,,-`-`,,`,,`,`,,` - API STAFF CONTACT EXECUTIVE SUMMARY The American Petroleum Institute (API) sponsored a workshop (October 11-12, 1994) to address produced water toxicity limits and potential treatment methods Organized by APl’s Toxicity Reduction Evaluation (TRE) workgroup, the workshop brought together experts in the fields of toxicology and engineering to: identify technologies that could potentially be used to reduce the toxicity of producedwater (Pw) discharges; and o review and evaluate the technical feasibility and economics of using these treatment technologies on offshore platforms The first day of the workshop consisted of presentations on (I) the characteristics and toxicity of produced water, (2) results of tests to identify the causes of PW toxicity using Toxicity IdentificationEvaluation (TIE) procedures, and (3) engineering constraints impacting offshore produced water treatment In addition, technical informationwas presentedon five candidate treatment technologies: membrane filtration, carbon adsorption, chemical oxidation, stripping/extraction, and ultraviolet (UV) irradiation Produced water is variable in composition and flow, but typically has high salinity (9% or greater) and high temperature (up to 14OOC) and contains a variety of compounds, including hydrogen sulfide, ammonia, hydrocarbons, carboxylic acids, phenols, heavy metals and radium Phase I TIE procedures have been applied to producedwater to characterize the properties of the major fractions contributing to toxicity This testing indicated that the causes of PW toxicity vary depending on the source TIE procedureshave identified a variety of components contributing to PW toxicity including: particulates, salinity; volatile compounds; extractable organics (acidic, basic, neutral); and compounds affected by pH adjustment Some individual components were tentatively identified, including ammonia and hydrogen sulfide The integrity of the sample is a concern when testing treatment technologies, because PW characteristics (reduced materials, high pressure, high temperature) may change when exposed to the atmosphere ES-1 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale `,,-`-`,,`,,`,`,,` - The Day presentations included the following major points: A P I DRa351 96 = 0732290 0553619 3T8 = o Offshore platforms, as sites for water treatment, have more stringent space, weight, and logistical limitations than onshore treatment facilities o Each of the technologies being considered for treatment of produced water toxicity has been successfully applied to onshore treatment of industrial wastes, which are sometimes similar to produced water in composition On the second day of the workshop, workgroups evaluated each candidate technology, including a sixth potential technology, biological treatment, identified on Day 1, The workgroup findings and recommendations were summarized in a discussion session at the end of Day The Day workgroups considered information provided on Day during their evaluations of each technology's applicability for the offshore treatment of produced water A technology checklist centered attention on the primary areas of interest, including the types of toxicants that might be removed, equipment specifications, operational status and potential for improvement, costs, and recommendations for research Strengths of the technologies include their efficiency in removing potential produced water toxicants and, in some cases, the ability to handle variable feed streams Weaknesses include the generation of waste streams that may require disposal, large size and weight requirements of the technologies, power requirements, and fouling and scaling potential Treatment costs were compared primarily to the costs of reinjecting the produced water Recommendationsfor additional research were summarized in a final discussion session on the second day of the Workshop Testing of the effect of emerging treatment technologies on PW toxicity was cited as a primary research need A closer alignment between TIE procedures and treatability studies of the technologies was recommended An approach was recommended for testing on several produced waters in the Gulf of Mexico to develop case study information The suggested approach involved adapting the TIE procedures to more closely approximate the treatment technologies, offshore pilot testing to confirm toxicity reduction, and final testing to develop design and operating criteria In summary, the Workshop reviewed technologies potentially capable of treating produced water toxicity in offshore applications All of the technologies discussed have the potential to be used for produced water toxicity treatment; but, in all cases, further research and bench- and pilot-scale testing is necessary to investigate their effectiveness in this application To date, none of the technologies have been specifically tested for their ability to reduce toxicity in produced water ES-2 `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale A P I DR*35L ỵ b 0732290 0553b20 O l T TABLE OF CONTENTS Pane EXECUTIVE SUMMARY INTRODUCTION e5-1 1-1 PURPOSE 1-1 ORGANIZATION OF THE PROCEEDINGS 1-2 TECHNICAL BACKGROUND 2-1 PRODUCED WATER DISCHARGE 2-1 Toxicity Limits for Produced Water 2-1 Proposed Effluent Toxicity Targets 2-3 Produced Water Toxicants 2-3 Produced Water Composition 2-4 ENGINEERING CONSIDERATIONS FOR OFFSHORE PRODUCED WATER TREATMENT 2-5 PROCEEDINGS DAY OCTOBER 11 1994 OVERVIEW 3-1 3-2 Source of Produced Water 3-2 Composition of Produced Water 3-2 Properties and Characteristicsof Produced Water 3-3 Chemical Additives 3-3 Conclusions 3-4 TOXICOLOGICAL EVALUATION OF PRODUCED WATEWEFFECTS OF ION COMPOSITION ON TOXICITY 3-5 Why Toxicity is Used as a Monitoring Tool 3-5 Toxicity Identification Evaluation Ion Composition of Produced Water How Toxicity is Measured Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale 3-5 3-6 3-7 `,,-`-`,,`,,`,`,,` - DERIVATION COMPOSITION AND MANAGEMENT OF PRODUCED WATERS 3-1 A P I DRL351 96 = 0732290 0553b21 T5b m TABLE OF CONTENTS (CONTINUED) Section Paae PROCEEDINGS DAY OCTOBER 11 1994 (Con’t) RESULTS OF TOXICITY IDENTIFICATION EVALUATION STUDIES ON PRODUCED WATERS 3-9 3-9 3-9 3-10 INTEGRATING TOXICOLOGICAL INFORMATION INTO TREATMENT SELECTION AND DESIGN 3-12 3-12 Effluent Treatment and Toxicity 3-12 Effluent Characteristics 3-13 On-site Testing 3-13 Causes of Toxicity PRODUCED WATER TREATMENT: ENGINEERING REQUIREMENTS ANDCONSTRAINTS 3-14 Background 3-14 Goals of Offshore Production Facilities 3-14 Basic Treatment Requirements 3-15 Cost and space Limitations on Typical Offshore Platforms 3-16 QUESTION AND ANSWER SESSION 3-17 MEMBRANE FILTRATION 3-20 3-20 Conclusions Background 3-18 3-20 Membranes and Fouling 3-20 Costs of Membrane Treatment 3-20 Experiences with Membranes and Produced Water 3-21 Ideas for the Future 3-21 CARBON ADSORPTION 3-22 Performance of Membranes Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale `,,-`-`,,`,,`,`,,` - Methods Results Produced Water Toxicants Background to the API TIE Study ~ API DRw351 96 2 O553622 9 = TABLE OF CONTENTS (CONTINUED) Paae PROCEEDINGS DAY OCTOBER 11 1994 (Con’t) Pretreatment Requirements Typical Specifications and Costs CHEMICAL OXIDATION Background 3-22 3-24 Background Chemical Reactions 3-22 3-23 3-24 3-24 3-25 Economics of Chemical Oxidation 3-26 STRIPPING/EXTRACTION 3-27 Background 3-27 Removal Efficiency Data 3-27 Problems with Air Stripping of Produced Water 3-28 Design of a Packed Tower 3-28 Costs of Air Stripping 3-29 UV/OXIDATION 3-30 Background 3-30 Experience with UVlOxidation 3-30 Experimentation `,,-`-`,,`,,`,`,,` - Design of a UV/Oxidation System 3-31 3-31 Costs of UV/Oxidation 3-31 TECHNOLOGY SELECTION AND COSTS 3-33 Background 3-33 Problems with UV/Oxidation 3-33 3-34 The Produced Water Management Options Model Results of the Model Conclusions ROUNDTABLE DISCUSSION Miscellaneous Comments Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale 3-34 3-35 3-35 ~~ ~ ~ A P I DR*353 96 W 0732290 0553738 342 Evaluate cycle life, potential fouling, cleaning strategies and operating conditions and costs Evaluate toxicity/toxicant reduction capability and potential for adding toxicity (¡.e., from filter) Evaluate membrane choice and operating pressure 13 Are there any fatal flaws in applying this technology to produced water toxicity treatment? Possible fouling UV Irradiation Technoloav WorksrouD Participants: Jerry Hall, Moderator Dan Nolan, Expert Jerry Ham James Buzan Greg Hardy Joe Smith Answers t o Technoloav Checklist Questions How well technologies treat (reduce the concentrations of) spec fic chemica groups (e.g., volatiles, metals, H,S, ammonia and organics)? (Note: salinity is incorporated as a matrix effect) UV increases rate of oxidation by a factor of lo6 over simple chemical oxidation Destroys dissolved organics, volatile and non-volatile organic compounds , inc Iud ing BTEX (Note: stripping will be cheaper for volatiles unless off gas treatment is necessary) Napthenic acids will be destroyed at a lower rate than BTX H,S will also be oxidized, but UV/ozone.is not the method of choice A-24 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale `,,-`-`,,`,,`,`,,` - A P I DRx351 96 m 0732290 0553719 289 W Will not destroy ammonia or dispersed oil droplets Dispersed oil will just pass through - no interferences and no effect of process anticipated Will not destroy metals or salinity Salinity as carbonates will slow down reaction by scavenging hydroxyl radicals Contaminants such as biocides and other treatment chemicals used on platforms will also be destroyed if they are organic based Rate of destruction will vary by compound May be able to allow only partial removals and still achieve compliance with toxicity limit Is additional chemical usage necessary to reduce toxicity? There are a number of UV processes that can be used for produced water treatment UV usually done with hydrogen peroxide, but need to minimize chemical usage on platform Therefore, recommend UV together with ozone Easier to supply additional power for ozonator than deal with chemical storage, handling and safety issues What range of oil and grease and salinity can the technology tolerate? Salinity: `,,-`-`,,`,,`,`,,` - Jerry Hall - Studies performed by Texaco show that salinity in excess of natural sea water salinity did not inhibit UV treatment Reduced TOC to few ppm even at natural sea water salinity - but did not necessarily remove toxicity (no data) Salinity can cause corrosion, may need to upgrade piping from stainless to high molybdenum alloy or possibly FRP (fiberglass reinforced plastic) High carbonate concentrations will slow down reaction Oil: Oil will just pass through the system However, there is some concern about fouling the lamps A-25 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale A P I DR*351 b = 0732290 0553720 T T O = Other: Jerry Hall - Experience with UV operation is that wipers must be used in the presence of high iron concentrations Otherwise fouling will occur What are the equipment specifications? Open tower with UV lamps distributed a t various heights Weight limit on platform is 200 Ib/sf May require some configuration other than vertical tower Shape of equipment is irrelevant Electrical motors must be Class Division (explosion-proof) Vessels above 12 to 13 psi must be pressure coded May significantly increase costs; need to check in engineering study Additional power requirements - For 10,000 bbl/d UV/ozone unit, need 270 kW ( 79 kW for UV and 90 kW for ozone) UV/peroxide unit also 270 kW (for UV power) What is technology's current operational state (¡.e., pilot, laboratory-scale or full-scale)? Pilot Studies: `,,-`-`,,`,,`,`,,` - Performed tests on Gulf of Mexico samples in March 1992 Developed preliminary estimates for North Sea systems Greg Hardy: Solarchem to perform Rayox pilot testing with PERF in late November on a Shell platform Purpose is to evaluate operation and performance of the unit Produced water flow is 14,000 bbl/d Have soluble oil problem; oil and grease = 20 ppm on up Also toxicity failures Small Rayox tower - f t diameter by f t height, 1kW lamps at various heights in the column Will only treat about gpm continuously, but will provide kinetic data to evaluate design and operating requirements for full-scale A-26 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale A P I DRm351 ỵ b 0732290 0553723 937 W May also need t o first perform batch testing t o provide kinetic data Will look into performing toxicity tests on Rayox effluent Will look into treating acid-flow back wastes from well, because it elevates oil and depresses pH (worse case condition) Commercial Applications: Solarchem has sold 70 units - 50 t o 60 in use About 200 installations in U.S used t o treat similar types of compounds No definitive work on produced water Will the wiper be able t o keep the quartz sleeve clean enough for light t o penetrate the water Need field experience, pilot studies planned Operations and Maintenance: Designed t o operate with little attention Have been operating remotely by modem Operates by programmable logic controller (PLC) Lamps last a minimum of 3,000 hours (4 months) Lamps can be changed quickly (1 per hour) Rayox will accept old lamps because they contain a small amount of mercury Air compressor used for wiper needs t o be maintained Possibility of pinhole leaks in glass and gas coming out will ignite M o s t systems are operated continuously Batch is used for unpredictable conditions such as variable waste stream characteristics produced water treatment should be continuous t o minimize operator attention What is the potential for technology improvements (Le., many versus few, rapid versus slow) A-27 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale `,,-`-`,,`,,`,`,,` - Experience with some UV/peroxide systems is that pH monitoring is required t o guard against fouling ~ A P I D R x 96 = 0732290 0553722 873 m For large scale system, more economical t o produce ozone from oxygen than from air Put pressure adsorption unit t o increase oxygen concentration t o 75 t o 90% and then pass the enriched air through ozone generator Oxygen can be a safety issue Wiper may or may not work for produced water Need further work t o develop appropriate wiper materials - For high salinity waters need t o use something other than stainless steel for brush material Need t o k n o w what the toxicants are in order t o better address improvements May not be necessary t o treat all of waste stream t o meet toxicity limit Are there any toxicity reduction performance data? No, not for produced water Western Ontario study - evaluating toxicity reduction (microbial test) in specific chemical testing of pentachlorophenol destruction Some groundwater applications for treatment of solvents require toxicity tests before surface water discharge (freshwater) Rayox effluents are passing the tests Jerry Hall: Has in-house data on complex wastewaters and specific chemical tests (napthenic acids) List the advantages and disadvantages with regard to weight, size, energy requirements, produced water residence time, throughput capacity, input/loading rates, operating temperatures, waste stream types, fouling potential and scaling potential Advantages: Will destroy water soluble material Will not generate waste stream Will handle upset - high loading conditions (flow and slugs) Have been designed for high flow `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS - 600 gpm (20,000 bbl) A-28 Not for Resale A P I D R x 9b 0732290 0553723 T Disadvantages: Relatively high power requirements Will not treat dispersed oil Uncertainty about fouling potential Economics unknown for explosion-proof requirements Operator training required Describe any side effects from use of the technology (e.g., side stream wastes or alteration of ionic composition) Won't be adding chemicals that will cause toxicity If peroxide is used, residual may be toxic Example in South Carolina where peroxide was toxic to Daphnia 1O Consider appropriateness, or necessity, of sequential use of treatment technologies Note which technologies are compatiblelincompatible Need to use existing technologies for oil removal May need additional pretreatment if fouling is a problem Is compatible with other technologies 11 Evaluate cost as best as possible Summarize overall costs here Assuming a 10,000 bbl/d UV/ozone system and 90% destruction of BTX, the capital and operating costs are summarized as follows: Capital Costs: $500,000 for Rayox UV/ozone system $350,000 for Rayox UV/peroxide system A-29 `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale ~~ A P I DR*35L m 0732290 0553729 blib m Operating costs: $0.024 per bbl - includes electric power for lamps and ozone generator, and replacement of lamps a t 3,000 hours Additional generator capital cost would be about $0.04 to 0.05 per kWh If additional generator cost is included in operating costs, total operating costs are estimated to be $0.05 per bbl Power not a fatal flaw 12 List any recommendations for research needed to make the technology more practical for offshore use Need to evaluate lamp fouling Wiper operated by PLC may need to be adjusted to brush more frequently Testing for toxicity reduction Evaluation of cost to address Class I requirements (explosion-proof), pressure vessel requirements and corrosion potential StriDDina/Extract¡on WorkarouD ParticiDants: Tracy Fowler, Moderator David Hand, Expert Don Mount Michael MacNaughton Backqround The question of whether or not to address extraction treatment in addition to stripping was discussed Solubility is important for extraction Extract with solvent Put extracted material in oil stream? Workgroup decided to primarily address stripping Extraction is discussed in Question #10 of the Technology Checklist A-30 `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale ~ A P I DRx352 96 0732290 0553725 582 Answers t o Technoloqv Checklist Questions How well technologies treat (reduce the concentrations of) specific chemical groups (e.g., volatiles, metals, H,S, ammonia and organics)? (Note: salinity is incorporated as a matrix effect) > 0.005; expect 95% a For volatile compounds with Henry's Constant removal and greater a A t room temperature, H,S and ammonia can be stripped, but pH must be adjusted For H,S, pH should be lower (pH t o 6) For ammonia, pH should be higher (pH IO) a No distinction necessary between acidic, bosk, and neutral organics o Ferrous iron may be oxidized by air stripping and could foul equipment a Solubility of oxygen is reduced at higher temperature, so oxidizable materials may not be easily oxidized o Volatile emissions should not be an OSHA problem, at the air t o water ratios of interest Also volatile concentrations are relatively low a Mount noted that not many of the produced waters tested by Sauer had toxicity that was reduced by aeration However, it is important t o note that the aeration step in the TIE is not as efficient as air stripping treatment a Hand stated that benzene, toluene, naphthalene, phenanthrene, anthracene, pyrene, phenol can be removed effectively O May not need high removal efficiencies t o remove the toxicants t o nontoxic levels Also maybe just treat part of the waste stream a High temperature should increase the removal of semi-volatiles by stripping a Very little data on Henry's Law Constants at elevated temperatures Is additional chemical usage necessary t o reduce toxicity? Acid and base addition is necessary for H,S and ammonia removal, respectively `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS A-31 Not for Resale Possible precipitation of inorganics such as calcium and magnesium Can continuously add acid to feed or periodically acid wash tower produced water is unstable Temperature will change and precipitates will form from contact with air What range of oil and grease and salinity can the technology tolerate? Salinity increases the Henry’s Law Constant by 20 t o 30% which will increase stripping efficiency Definition of oil: Dispersed versus soluble (dissolved) Measured gravimetrically or by IR Oil may coat the packing and change surface tension of packing Unsure of overall effect May cause accumulation of suspended solids What are the equipment specifications? Minimal pumping requirements `,,-`-`,,`,,`,`,,` - Not a power intensive process Need a to hp blower for t o 1,500 gpm flow rate Air t o water ratio of v/v Low operating pressure tower Could be fiberglass or PVC Maybe use aerated tank instead of packed tower, especially if precipitation is a problem For 15,000 bbl/d (440 gpm) flow rate, t o diameter tower, 1O t o 20 f t height (height will depend on temperature effect and desired removal efficiency) Space: 20 sf for tower and 20 sf for blower etc Need separate off-gas vent May need t o put demister on off-gas vent because of condensate formation related t o temperature difference between air and produced water May need equipment for off-gas capture and treatment (e.g., scrubber) A-32 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale API DR*35L 96 = 0732290 0553727 355 What is technology’s current operational state (Le., pilot, laboratory-scale or full-scale)? Many commercial applications None for produced water treatment What is the potential for technology improvements (¡.e., many versus few, rapid versus slow) Need to optimize for specific applications Potential for improvements is slow, although there have been recent advances in packing material Are there any toxicity reduction performance data? TIE work on produced water, especially in Wyoming, shows that toxicity can be removed by aeration In these cases, toxicity is probably due t o H,S Sample integrity is important for TIE or treatability testing Use sample collected in the same way as for toxicity compliance tests For example, samples exposed t o air during shipping may not have same toxicity as produced water discharged directly t o receiving water List the advantages and disadvantages with regard t o weight, size, energy requirements, produced water residence time, throughput capacity, inputlloading rates, operating temperatures, waste stream types, fouling potential and scaling potential Size: small footprint; 20 sf for tower and 20 sf for blower etc Weight: low Energy Requirements: low, t o hp blower produced water Residence Time: up t o 1,500 gpm flow rate Operating Temperatures: High temperature ( 4OOF) should increase removal efficiencies Waste Stream Types: off-gas may be a problem if treatment is required for air pollution regulations A-33 `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale A P I DR*351 96 m 0732290 0553728 291 m Fouling: maybe by oil Scaling: Iron and calcium precipitation Not manpower intensive, simple t o operate No chemicals needed except maybe acid and base for H2S and ammonia removal, respectively Well known technology Describe any side effects from use of the technology (e.g., side stream wastes or alteration of ionic composition) Off-gas waste stream treatment may be necessary Potential precipitation of solids 1O Consider appropriateness, or necessity, of sequential use of treatment technologies Note which technologies are compatible/incompatible `,,-`-`,,`,,`,`,,` - Off-gas treatment (low temperature catalysis, activated carbon, venting, flaring) or injection into natural gas stream Low temperature catalysis may be the best option because it can be accomplished at the observed temperature of produced water ( 140 O F ) Pretreatment for removal of iron may be necessary If pH adjustment is used for ammonia or H2S removal, neutralization may be needed before discharge Extract ion Techno Iogy : Recirculating solvent extraction system or pressure swing absorption Extraction would take out non-volatile organic materials (low Henry’s Law Constants) Need t o consider logistics of supplying solvent Requires solvent regeneration and disposal of removed components A-34 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale TIE data show that non-volatile materials in produced water (¡.e., substances removed by solvents) are more of a problem than volatile substances Solvents may add toxicity; therefore, post treatment (aeration) may be needed Carbon adsorption is an alternative t o extraction 11 Evaluate cost as best as possible Summarize overall costs here Packed tower air stripping is $0.02 t o O 1O per 1,000 gal of water (includes amortized capital cost and operating cost) Electrical power is 80% of operating costs Off-gas control b y activated carbon will add $0.50 t o 1.50 per 1,000 gal of water Off-gas will be high temperature; therefore, use low temperature catalysis system If off-gas didn’t contain oxygen, maybe put in gas pipeline Would require a compressor Scale and fouling control would also add costs Fowler: Discussed Simon Davies article in Offshore Magazine (September 1994) Dissolved component removal by Norwegian Oil Industry Assoc.: Ion Exchange $315 M Activated Carbon $325 M Biological: $190 M Air Stripping: $53 M (doesn’t say that off-gas treatment required) A-35 `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale 12 List any recommendations for research needed t o make the technology more practical for offshore use Additional research needed on: Henry's Law Constants a t high temperature and high salinity Effect of oil on stripping efficiency Pilot-scale tests to evaluate toxicity reduction, scaling and fouling Need more TIE research to determine characteristics of produced water toxicity Also perform TIE tests that simulate the treatment technologies to evaluate the effectiveness of the technologies for toxicity reduction `,,-`-`,,`,,`,`,,` - Review the regulations regarding off-gas discharge A-36 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale ~~ ~ A P I DR*351 96 ~ ~ = 0732290 0553731 88b = `,,-`-`,,`,,`,`,,` - 06962C1 P Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale - ~~ API DR*35L American Petroleum Insti tute 96 m 0732290 O553732 712 1220 L Street, Northwest Washington, D.C 20005 202-682-8000 `,,-`-`,,`,,`,`,,` - http:llwww.api.org Order No 100351 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale