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ABSTRACT A range of new on-line actives based monitoring and control techniques are discussed, including a new method for the on-line measurement and control of treatment program polymer. The impact of measuring key active treatment components is demonstrated through improved system performance. Laboratory studies and case histories are presented. INTRODUCTION Maintaining heat exchanger and cooling tower efficiencies at design specifications requires careful establishment and control of the cooling water treatment program. Chemical analysis of individual treatment program components, including corrosion and scale inhibitors, is usually recommended, often on a daily or more frequent basis. Water samples are typically withdrawn as grab samples and appropriate field test methods used. For many cooling systems, grab sample chemical analysis is not sufficient to ensure optimum treatment levels. In critical or more complex systems, grab sample analysis may be coupled with mass balance or inert tracer based chemical feed systems. The mass balance approach to cooling water treatment feed works well in many instances, however, if there are un-metered makeup or water losses, there is potential for underfeed of treatment chemicals. Results from inert tracer based feed systems may not correlate to the levels of scale and corrosion inhibitor because the tracer cannot take into account individual reactions or demand that different active treatment components may undergo. These limitations have led to the increased used of on-line automated feed and control systems based on the analysis of treatment program active ingredients. The use of on-line actives analyzers is gaining in acceptance as a means for improving treatment program results, while also reducing testing and manpower requirements for manual grab sample analysis. Other advantages include, reduced treatment costs and the ability to respond real-time to changes in system operating conditions. On-line analyzers for measurement and control of phosphate, phosphonate and molybdate have been discussed in the literature.l'2 In addition to these treatment components, polymeric dispersants are also a key active ingredient in most cooling water programs. Polymers play a vital role in the inhibition and dispersancy of scale forming salts and in the dispersion of particulate materials such as silt and sand. Polymers are also important in regulating the rate and extent of many corrosion inhibitor film processes. Owing to their importance in today's water treatment programs, several new polymer measurement methods have recently been developed. 3'4'5 Although providing important advantages for the measurement of treatment program polymer, the new methods are primarily grab sample based. Techniques for the on-line direct measurement of polymeric dispersants are rare and have remained elusive. This paper will review recent advancements in cooling water on-line actives based monitoring and will describe a new method for the on-line direct measurement and control of polymer. Results are presented which will demonstrate advantages of on-line polymer monitoring with emphasis on correlation to treatment program performance. TECHNIQUES AND METHODOLOGY On-Line Analysis Of Phosphate, Phosphonate And Molybdate. Grab sample reagent methods for measurement of active components such as phosphate, phosphonate, and molybdate are widely used and well documented. Many conventional reagent-based techniques have been successfully adapted to on- line analysis instruments. The most modem instruments available today are much more reliable than their predecessors and require less routine maintenance. Some key advantages of reagent-based on-lin
- Overview > Innovation (0.75)
- Research Report (0.48)
- Water & Waste Management > Water Management > Water Supplies & Services (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
- Data Science & Engineering Analytics > Information Management and Systems (1.00)
- (2 more...)
ABSTRACT A diffusion based controlled release technology is now being used as a method to introduce chemistry into an open recirculating cooling system. Controlled release technology applied to a cooling tower water treatment program enables accurate delivery of chemistry without the use of mechanical pumps or handling of liquid chemicals. Our laboratory work examined how factors such as formulation, temperature, flow, and coating weight affect this feed method. In addition to the technology overview, case studies of current applications will be presented. INTRODUCTION Controlled release technology (CRT) is a field of chemistry focused on controlling the release of active chemical agents into a working system. The working system may be anything from a human body to agricultural soil and even a diesel engine cooling system. CRT is employed for several reasons; among them are the protection of sensitive materials, control of the timing of release, and control of the point of release. Often CRT is used to protect sensitive chemical agents. For example, enteric coatings in the pharmaceutical industry protect the active ingredient from the very acidic conditions of the stomach. The acidic environment could render the chemical inactive. With a protective coating on a tablet, the drug safely passes thru the stomach to the small intestine where the drug can be absorbed. Conversely, an enteric-coated aspirin protects the lining of the stomach for frequent users. CRT has in recent years allowed more convenient methods of chemical or drug delivery. For example, the development of the "patch" has offered an easy and effective way to administer long-lasting dosages of prescription drugs simply by placing an adhesive strip on the skin. With this mechanism the drug is absorbed thru the skin at a controlled rate for some duration of time. Other industries also use CRT to design better products with some unique performance characteristic. For example, the heavy-duty diesel engine coolant industry has long used coated tablets to effect diffusion based controlled release, as a means to introduce and maintain appropriate concentrations of corrosion and scale inhibitors in closed loop recirculating cooling systems. The controlled release of chemistry into the cooling system is accomplished by the slow, consistent diffusion of the active material through a polymeric tablet coating. In these closed systems, coated tablets are packaged inside a spin-on filter that allows the cooling system on a diesel engine to be protected for up to 150,000 miles or 3000 hours. Cooling tower water treatment shares many similarities with the heavy-duty engine cooling industry. For example, the chemistry of corrosion and scale inhibition is not unique to either industry. In fact, both industries have built their foundations in this very important component of protecting and maintaining process equipment, particularly metal surfaces. It is well understood that water treatment and specifically, a stringent maintenance practice can eliminate damage to equipment, which can lead to many costly repairs. Currently, in the water treatment industry, with specific regard to cooling towers, liquid products and pumping systems are used as the predominate means to deliver chemistry to openrecirculating cooling systems.
- Research Report (0.46)
- Overview (0.34)
- Water & Waste Management > Water Management > Lifecycle > Treatment (1.00)
- Health & Medicine (1.00)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology (1.00)
- Health, Safety, Environment & Sustainability > Environment > Water use, produced water discharge and disposal (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
Abstract The efficient utilization of automation systems necessitates a clear understanding of the interaction of the human operator, the automation system and any automated routines being run. If automated routines perform actions not desirable to the human operator, time is lost as the routine is interrupted and human control re-engaged. In addition, automatic handoff back to the human operator, both due to human intervention and due to exist conditions or anomalies must also be managed. Activity data from rigs across North America is analyzed to understand automation process utilization and interrupt timing. Realtime and historic data is tagged, either automatically, semi-automatically using machine learning, or manually, to create a minute-by-minute timeline of rig operations. Operations are then classified both by operation โ steering, reaming, making hole, etc. โ and well plan to understand how operational demands change automation system utilization. This results in a new set of metrics which can be used to precisely quantify the performance metrics of both the human and automated drilling systems. Performance of the automation system is found to be a strong function of hole deviation with the system outperforming during simple operations and in the vertical hole, but with reduced performance while in the curve and horizontal, due to high interruption of certain tasks. It is found that standard performance metrics, such as slip to slip or weight to weight are affected by standard practices and if these are used to grade system performance, these practices must be account for. This paper presents a detailed investigation of the interaction of the driller with an automated drilling automation system and lays out the utilization of the automation system as a function of rig operations and well path. It is specially noted that standard performance metrics must consider standard practices which may differ between operations.
- Well Drilling > Drilling Equipment (1.00)
- Well Drilling > Drilling Automation (1.00)
- Well Drilling > Drillstring Design > Drill pipe selection (0.97)
Abstract The use of corrosion inhibition has been a common practice in industry to protect oil and gas pipelines made of carbon steel and exposed to wet hydrocarbons containing CO2 and H2S. It is however important to emphasize that the inhibitor efficiency is highly dependent on its capability to be present in the water phase and reach the pipe wall. Therefore, for a given corrosion inhibitor injection rate, there is a need to quantify the amounts of the active components present in the water and the oil phases as well as any loss to the solid surfaces, particularly to scale and corrosion products or sand if present. This paper focuses on the use of an in-house developed laboratory method to quantify the partitioning of the corrosion inhibitor between the oil, water and solid phases and evaluate its performance as such. The partitioning of the inhibitor is evaluated using a modified standard LPR (Linear Polarization Resistance) corrosion test, followed by an analysis of the corrosion inhibitor residuals in the various phases using an LC-MS (Liquid Chromatography-Mass Spectroscopy) analytical method (Blumer and Johlman, 2008). The major active components of the inhibitor are traced using such analysis. The paper presents an illustration of the testing method and the obtained results. Introduction In most applications where corrosion inhibitors are used to mitigate CO2/H2S corrosion, more than a single phase is present in the system. Therefore, when the inhibitor is applied, its components are inevitably distributed between the phases mainly the oil, the brine and the solids (Matherly et al., 1995). As corrosion occurs on water wetted metal surfaces, the presence of the adequate amount and type of active components of the inhibitor in the water phase is vital to provide protection. Failures partially due to the presence of solids in pipelines have been reported in the oil and gas industry in various applications. The solid deposits can be of various types, including sand, scale and corrosion products. Corrosion inhibitors can be used to mitigate such corrosion seldom combined with aggressive pigging programs on a regular basis (Gough and Langley, 1998). The presence of solids can interfere with the performance of the inhibitor in several ways. When present on the pipe wall, solids constitute an extra physical layer that the inhibitor has to overcome in order to get to the surface and therefore mass transfer limitations can occur (Achour, 2007). These solids will also adsorb the active components of the inhibitor and may cause under dosage of the inhibitor if these losses are not considered (Achour et al., 2008; Christov and Popova, 2004; Son and Muckleroy, 1997). Moreover, the accumulation of the solids can constitute a localized cell providing ideal conditions for bacteria to grow. Controlling the partitioning of the inhibitor in an oil/water/solids system will enable to select the adequate corrosion inhibitor dosage required for protection (Joosten et al., 2000; Moon and Horsup. 2000; Blumer and Babcock, 1996). All these issues drive for the need of a reliable method to quantify the presence of the active components of a given corrosion inhibitor between the various phases present in a wet hydrocarbon system.. It is within this framework that the present paper describes a partitioning test followed by an analytical method used to provide such information. The method will be illustrated.
- Water & Waste Management > Water Management > Water & Sanitation Products (1.00)
- Materials > Chemicals > Specialty Chemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Energy > Oil & Gas > Midstream (1.00)
Abstract The efficacy of many commonly used biocides is often determined by laboratory evaluations against a variety of planktonic microorganisms. While these tests provide some information as to the performance of a biocide against a particular microorganism, they may not predict how well the biocide will perform under actual field conditions against the more problematic sessile form of the organisms. In order to address the issue of how well a biocide penetrates and kills the problematic microorganisms contained within a biofilm, an artificial biofilm system utilizing microorganisms embedded in alginate beads has been used to compare the efficacy of biocide treatments against both the planktonic and sessile form of the same organism. Pure cultures of Enterobacter aerogenes, as well as mixed field isolates, were used in the experiments. In addition, the alginate beads were prepared with actual system waters taken from a variety of industrial applications. In that way, all of the scale and corrosion inhibitors and other contaminants which are present in the actual system are also present in the model biofilm system. In all cases, the organisms contained within the artificial biofilm were significantly more difficult to kill than the corresponding planktonic microbes. INTRODUCTION Microbially induced corrosion (MIC) of metal surfaces is a major concern in any industrial system which uses large quantities of water. Biofilms, or specifically the organisms contained within the biofilm, are usually responsible for the MIC. Biofilms are a complex mixture of microorganisms, cellular by-products and entrained debris. A cellular polysaccharide sheath develops which helps to protect the biofilm by trapping nutrients from the water, and by shielding it from biocides. Sulfate-reducing bacteria are perhaps the most notorious members contained in the biofilm community, and contribute to MIC by their ability to metabolize exogenous sulfate to sulfide. Hydrogen sulfide, being corrosive by nature, not only corrodes exposed metal surfaces but could also lead to health problems in exposed workers due to its toxicity.Traditional methods of controlling biofouling and biofilm formation involve either mechanical or chemical cleaning. Mechanical methods, often the quickest method to remove a biofilm, usually require time consuming and expensive manual labor to clean the metal surfaces of the system. Chemical cleaning ideally involves adding a biocide to kill both the microorganisms in suspension (planktonic microorganisms), as well as those contained within the biofilm (sessile microorganisms). However, merely killing planktonic organisms will not solve the biofouling problem in a system. Ideally, biocide treatments should kill both sessile and planktonic organisms. To be truly effective against biofilm, a biocide needs to penetrate and kill the microorganisms contained within the biofilm. The choice of chemical cleaning agents is often based on laboratory evaluations of various biocides which have been tested against a variety of planktonic microorganisms. While these tests provide some information as to the performance of a biocide against a particular microorganism, they may not predict how well the biocide will perform in the field against the more problematic sessile organisms.
- North America > United States (0.48)
- Europe > United Kingdom (0.47)