The Challenges Associated with Reaction Products Left in Scale Inhibitor Species after Radical Polymerization

2014 ◽  
Author(s):  
Jonathan J. Wylde
Keyword(s):  
Thermal Stability ◽  
Hydrogen Peroxide ◽  
Free Radical ◽  
Transition Metal ◽  
Radical Polymerization ◽  
Average Molecular Weight ◽  
Oil And Gas Industry ◽  
Reaction Products ◽  
Scale Inhibitor ◽  
End User

Abstract The use of polymeric scale inhibitors has been ubiquitously accepted by the oil and gas industry for many years. There are many benefits to the use of this type of chemistry that include aspects such as high performance, scale species selectivity, enhanced brine compatibility, favorable environmental properties and high thermal stability. A very common way to manufacture polymeric scale inhibitors is via free radical polymerization. Here an initiator is used to propagate the generation of free radicals from a species, such as hydrogen peroxide. The initiator chemistry can be very varied and usually comprises different types of transition metal salts, hypophosphite or persulfate species. Different monomer units can be polymerized using different initiator and free radical species to yield the same polymer. However, subtle differences can result, including poly-dispersity, average molecular weight and different residual composition. The implications for the end user of the chemistry can be profound regarding performance differences in aspects such as detectability, compatibility, thermal stability and sometimes even scale inhibition and adsorption efficacy. A case study has been presented where a very commonly used sulfonated copolymer species from four different sources was evaluated in a whole host of compatibility and performance tests. The different routes used different combinations of hydrogen peroxide and transition metal initiator or persulfate/hypophosphite combinations as the free radical source. There were major differences seen in the compatibility of these products with different scale inhibitors and then in performance. The tests performed highlighted the differences that can occur between the different radical polymerization synthetic routes mentioned above. The conclusions show that there are many benefits to being able to control the manufacturing process of scale inhibitor species in order to ensure the full composition is understood and can be quantified. The benefits to owning the supply chain are highlighted and lead to not only better control of quality and cost but, more importantly, to the overall risk reduction for the end user in the end use application.

scholarly journals Initiator Feeding Policies in Semi-Batch Free Radical Polymerization: A Monte Carlo Study

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1291 ◽  
Author(s):  
Ali Seyedi ◽  
Mohammad Najafi ◽  
Gregory T. Russell ◽  
Yousef Mohammadi ◽  
Eduardo Vivaldo-Lima ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Monte Carlo ◽  
Free Radical ◽  
Methyl Methacrylate ◽  
Radical Polymerization ◽  
Average Molecular Weight ◽  
Free Radical Polymerization ◽  
Monte Carlo Algorithm ◽  
Single Shot ◽  
The Impact

A Monte Carlo simulation algorithm is developed to visualize the impact of various initiator feeding policies on the kinetics of free radical polymerization. Three cases are studied: (1) general free radical polymerization using typical rate constants; (2) diffusion-controlled styrene free radical polymerization in a relatively small amount of solvent; and (3) methyl methacrylate free radical polymerization in solution. The number- and weight-average chain lengths, molecular weight distribution (MWD), and polymerization time were computed for each initiator feeding policy. The results show that a higher number of initiator shots throughout polymerization at a fixed amount of initiator significantly increases average molecular weight and broadens MWD. Similar results are also observed when most of the initiator is added at higher conversions. It is demonstrated that one can double the molecular weight of polystyrene and increase its dispersity by 50% through a four-shot instead of a single shot feeding policy. Similar behavior occurs in the case of methyl methacrylate, while the total time drops by about 5%. In addition, policies injecting initiator at high monomer conversions result in a higher unreacted initiator content in the final product. Lastly, simulation conversion-time profiles are in agreement with benchmark literature information for methyl methacrylate, which essentially validates the highly effective and flexible Monte Carlo algorithm developed in this work.

Novel Method for Real-Time Monitoring of Scale Control Products at the Site of Use

2014 ◽  
Author(s):  
James Johnstone ◽  
Susanna Toivonen ◽  
Rick Griffin ◽  
Ashleigh O'Brien ◽  
Paul Mundill ◽  
...  
Keyword(s):  
Produced Water ◽  
Average Molecular Weight ◽  
Oil And Gas Industry ◽  
Management Program ◽  
Field Analysis ◽  
Scale Inhibitor ◽  
Sample Collection ◽  
Residual Concentration ◽  
Wide Range ◽  
Scale Control

Abstract Scale inhibitors are used extensively in the oil and gas industry to provide the level of flow assurance required to maximise safe and economic hydrocarbon production. For both continuous and scale squeeze treatments, residual inhibitor concentrations need to be verified on a continual basis to assure the field operator that the implemented scale management program remains effective. To date, the analytical work required to verify residual inhibitor levels of the majority of scale inhibitor chemistries needs to be carried out onshore in a suitably equipped analytical laboratory. Often the time delay from sample collection to reporting of analytical results introduces a significant level of uncertainty with regard to effective scale control which, if removed, would substantially improve the production assurance and safety of the facility operations. The Residual Monitoring and Analysis system is a point-of-use monitoring platform designed to measure the residual concentration of polymeric scale inhibitors with average molecular weight less than 10 000 Da in produced water, providing a timely and accurate residual scale inhibitor concentration to the facility operator. The analysis procedure can be carried out at the production location where the sample is taken, with the result obtained and recorded within 30minutes or less. The analysis method is unaffected by either the presence of other production chemicals or by the variation in typical North Sea produced water composition. The measurement system utilises the Aqsens aqueous liquid fingerprinting technology platform (Hänninen et al. 2013) and can be designed to work with a wide range of scale inhibitor chemistries; a specific tag/label is not necessary. Unlike other systems, the analytical method is not based on immunoassay detection technology that requires modification of the scale inhibitor formulation to include tagged polymer-specific antibodies. We have deliberately reverse engineered this for a range of current scale inhibitor products to provide direct field analysis to customers on either continuous or scale squeeze application programs. The system derives its sensitivity by combining time-resolved fluorescence with carefully optimised chemistries to quantify the product for scale inhibition levels. Performance results from laboratory testing and coreflood experiments will be presented.

Dextran Sulphates Protect Porcine Arterial Endothelial Cells from Free Radical Injury

1994 ◽  
Vol 13 (4) ◽  
pp. 233-239 ◽  
Author(s):  
Linda M. Hiebert ◽  
Ji-Min Liu
Keyword(s):  
Hydrogen Peroxide ◽  
Endothelial Cells ◽  
Free Radical ◽  
Protective Effect ◽  
Cell Damage ◽  
Average Molecular Weight ◽  
Dextran Sulphate ◽  
Trypan Blue Exclusion ◽  
Arterial Endothelial Cells ◽  
Cell Medium

1 The ability of dextran sulphate to protect cultured porcine arterial endothelial cells injured by addition of xanthine and xanthine oxidase (X/XO) or hydrogen peroxide to cell medium was examined using a variety of drug preparations. Cell damage was assessed by determining cell viability (by trypan blue exclusion) and release of lactate dehydrogenase into the medium. 2 Dextran sulphates of average molecular weight (Mr) 5000, 8000 (hydrogenated or unhydrogenated) at 0.05, 0.5, 5 and 50 μg ml-1 medium, added 24 h prior to X/XO, protected cells, whereas dextran sulphate Mr 500,000 was protective only at 0.5 μg ml-1. 3 None of the dextran sulphates used showed any toxic effect on cells in concentrations up to 500 μg ml-1 medium. 4 When the duration of pretreatment with dextran sulphate Mr 8000 was varied, 6 h was required for a protective effect on cells damaged by X/XO, which was enhanced with durations of 16 and 24 h. 5 Dextran sulphates had a similar protective effect on cells damaged by hydrogen peroxide. 6 This study suggests that dextran sulphates may prevent conditions resulting from free radical injury.

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