Treatment of oilfield produced water was investigated using an anaerobic process coupled with micro-electrolysis (ME), focusing on changes in chemical oxygen demand (COD) and biodegradability. Results showed that ...Treatment of oilfield produced water was investigated using an anaerobic process coupled with micro-electrolysis (ME), focusing on changes in chemical oxygen demand (COD) and biodegradability. Results showed that COD exhibited an abnormal change in the single anaerobic system in which it increased within the first 168 hr, but then decreased to 222 mg/L after 360 hr. The biological oxygen demand (five-day) (BOD5)/COD ratio of the water increased from 0.05 to 0.15. Hydrocarbons in the wastewater, such as pectin, degraded to small molecules during the hydrolytic acidification process. Comparatively, the effect of ME was also investigated. The COD underwent a slight decrease and the BOD5/COD ratio of the water improved from 0,05 to 0.17 after ME. Removal of COD was 38.3% under the idealized ME conditions (pH 6.0), using iron and active carbon (80 and 40 g/L, respectively). Coupling the anaerobic process with ME accelerated the COD removal ratio (average removal was 53.3%). Gas chromatography/mass spectrometry was used to analyze organic species conversion. This integrated system appeared to be a useful option for the treatment of water produced in oilfields.展开更多
1.The need for global carbon monitoring from space and the TanSat mission Global warming is a major problem,for which carbon dioxide(CO2 )is the main greenhouse gas involved in heating the troposphere.However,the po...1.The need for global carbon monitoring from space and the TanSat mission Global warming is a major problem,for which carbon dioxide(CO2 )is the main greenhouse gas involved in heating the troposphere.However,the poor availability of global CO2 measurements makes it difficult to estimate CO2 emissions accurately.展开更多
The biological aerated filter (BAF) was used to treat the oil-field produced water. The removal efficiency for oil, COD, BOD and suspended solids (SS) was 76.3%-80.3%, 31.6%-57.9%, 8.6.3%-96.3% and76.4%--82.7%, re...The biological aerated filter (BAF) was used to treat the oil-field produced water. The removal efficiency for oil, COD, BOD and suspended solids (SS) was 76.3%-80.3%, 31.6%-57.9%, 8.6.3%-96.3% and76.4%--82.7%, respectively when the hydraulic loading rates varied from 016m·h^-1 to 1.4m·h^-1. The greatest partof removal, for example more than 80% of COD removal, occurred on the top 100cm of the media in BAF. The kinetic .performance of BAF indicated that the relationship of BOD removal efficiency with the hydraulic loadingrates, in biological aerated filters could be described by c1/c1=l-exp(-2.44/L^0.59). This equation could be used topredict the B OD.removal efficiency at different hydraulic loading rates.展开更多
The emulsion stability of oilfield produced water is related to the oil-water interfacial film strength and the zeta potential of the oil droplets. We investigated the effects of water treatment agents (corrosion inh...The emulsion stability of oilfield produced water is related to the oil-water interfacial film strength and the zeta potential of the oil droplets. We investigated the effects of water treatment agents (corrosion inhibitor SL-2, scale inhibitor HEDP, germicide 1227, and flocculant polyaluminium chloride PAC) on the stability of oilfield produced water. The influence of these treatment agents on oil-water interfacial properties and the mechanism of these agents acting on the oilfield produced water were studied by measuring the interfacial shear viscosity, interfacial tension and zeta electric potential. The results indicated that the scale inhibitor HEDP could increase the oil-water interfacial film strength, and it could also increase the absolute value of the zeta potential of oil droplets. HEDP played an important role in the stability of the emulsion. Polyaluminum chloride (PAC) reduced the stability of the emulsion by considerably decreasing the absolute value of the zeta potential of oil droplets. Corrosion inhibitor SL-2 and germicide 1227 could decrease the oil-water interfacial tension, whereas they had little influence on oil-water interfacial shear viscosity and oil-water interfacial electricity properties.展开更多
During the start-up and unstable combustion periods,even the state-of-the-art incinerators emit polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/PCDF) in stack gases at concentrations that are up to 1000 times...During the start-up and unstable combustion periods,even the state-of-the-art incinerators emit polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/PCDF) in stack gases at concentrations that are up to 1000 times higher than normal operation. Therefore,incinerators and other sources with variation of PCDD/PCDF release into air cannot be reliably monitored by the conventional short-term sampling that covers only 0.1%to 0.2%of the yearly operating time.A more comprehensive monitoring regime is required.This paper describes different applications of continuous PCDD/PCDF sampling in some European countries.The cases demonstrate that flexible regimes for continuous sampling can be crafted and applied by governments or regional/local authorities.Such regimes range from a countrywide,continuous requirement for selected facility types(e.g.,waste incinerators) to a facility-specific regime that applies,for example,to new facilities for a defined time period until the facility has demonstrated continuous compliance with regulatory limits. Countries implementing the Stockholm Convention are suggested to evaluate in their Best available technology/Best environmental practice(BAT/BEP) activities the usefulness of long-term sampling by,for example,designating institutes related to the environmental ministry or regional authorities to supervise long-term sampling regimes at relevant facilities in their country/areas,beginning with priority sources(e.g.,facilities used for destruction of persistent organic pollutants(POPs) or hazardous waste processing) . This paper presents and discusses the results of the AMESA long-term monitoring system having demonstrated that in addition to PCDD/PCDF all other unintentionally produced POPs listed in the Stockholm Convention could be supervised.展开更多
The interplay between chemistry and interfacial-tension-driven hydrodynamic instabilities has been studied experimentally. The system on hand consists of two immiscible liquids separated along an initially plane inter...The interplay between chemistry and interfacial-tension-driven hydrodynamic instabilities has been studied experimentally. The system on hand consists of two immiscible liquids separated along an initially plane interface at which an interfacial reaction takes place to produce in situ a surfactant. It is identified that the dynamics of the system depends on the orientation of the Hele-Shaw cell with respect to the vector of gravity. If the nele-Shaw cell is placed vertically, Marangoni cells with vigorous convection develop in both phases along a nearly planar interface. However, if the Hele-Shaw cell is tilted off the gravity, the instabilities in the system are characterized by the large scale interracial deformation with a spatio-temporal periodicity together with the chemo-Marangoni convection. The focus is on the exploration of the transition from the cellular mode to the large scale interfacial deformation.展开更多
Seventy-nine strains of bioflocculant-producing bacteria were isolated from 3 activated sludge samples. Among them, strain MYC was found to have the highest and stable flocculating rate for both kaolin clay suspension...Seventy-nine strains of bioflocculant-producing bacteria were isolated from 3 activated sludge samples. Among them, strain MYC was found to have the highest and stable flocculating rate for both kaolin clay suspension and oil-field produced water. The bacterial strain was identified as Klebsiella sp. MYC according to its morphological and biochemical characteristics and 16SrDNA sequence. The optimal medium for bioflocculant production by this bacterial strain was composed of cane sugar 20 g L^-1, KH2PO4 2 g L^-1, K2HPO4 5 g L^- 1, ( NH4)2SO4 0.2 g L^-1, urea 0.5 g L^- 1 and yeast extract 0.5 g L^- 1, the initial pH being 5.5. When the suspension of kaolin clay was treated with0.5% of Klebsiella sp. MYC culture broth, the flocculating rate reached more than 90.0% in the presence of 500mg L^-1 CaCI2, while the flocculating rate for oil-field produced water was near 80.0% in a pH range of 7.0 - 9.0 with the separation of oil and suspended particles from the oil-field produced water under similar conditions. The environment-friendly nature of the bioflocculant and high flocculating rate of the strain make the bioflocculant produced by Klebsiella sp. MYC an attractive bioflocculant in oil-field produced water treatment.展开更多
Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only ...Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only few were implemented on an industrial scale. Among those techniques, turbulence promoter can be more simple and effective in overcoming membrane fouling and enhancing membrane flux. As for the result that turbulence promoter increase fluid velocity, wall shear rates and produce secondary flows or instabilities, the influence of turbulence promoter was investigated on permeate flux during produced water ultrafiltration and the potential application of this arrangement for an industrial development. Experimental investigations were performed on 100 KDa molecular weight cut-off PVDF single-channel tubular membrane module using four kinds of turbulence promoters. It is observed that the significant flux enhancement in the range of 83%--164% was achieved while the hydraulic dissipated power per unit volume of permeate decreased from 31%--42%, which indicated that the using of turbulence promoter is more efficient than operation without the turbulence promoter. The effects of transmembrane pressure and cross-flow velocity with and without turbulence promoter were studied as well. Among the four kinds of turbulence promoters, winding inserts with 20.0 mm pitch and 1.0 mm wire diameter showed better performances than the others did.展开更多
To reveal the geochemical characters of water coproduced with coalbed gas and shallow groundwater,water samples were collected from 12 wells of coalbed methane and 7 wells of shallow groundwater.The pH,CODMn,fCO2,tota...To reveal the geochemical characters of water coproduced with coalbed gas and shallow groundwater,water samples were collected from 12 wells of coalbed methane and 7 wells of shallow groundwater.The pH,CODMn,fCO2,total dissolved solids (TDS),total hardness,and concentrations of metasilicic acid,sodium and kalium,calcium ion,magnesium ion,ammonium iron,bicarbonate ion,carbonate,chloride,sulfate ion,nitrate ion,fluoride,lithium,zinc,nickel,manganese,iron,boron,barium,etc.of the samples were measured.Research results showed the following:(1) Concentrations of TDS,chloride,fluoride,sodium and kalium,ammonium,iron,and barium in the water coproduced with coalbed gas exceeded the national standards of China; however,physical,chemical,and biological properties of shallow groundwater could meet the national standard.(2) The water produced from coalbed contained mainly Na-Cl·HCO3,with average TDS of 4588.5 ppm,whereas shallow groundwater contained a mixture of chemicals including Na.Mg.Ca-HCO3·SO4 and Na.Mg-HCO3·SO4,with average TDS of 663.8 ppm.(3) In general,it was observed that bicarbonate and sodium accumulated in a reducing environment and deeper system,while depletion of hydrogen ions and dissolution of sulfate,calcium,and magnesium occurred in a redox environment and shallow system.(4) Sodium and kalium,ammonium,chloride,and bicarbonate ions were the main ions found in the study area.展开更多
Produced water (PW) is the largest waste stream in the oil and gas industry. Water remains trapped for millions of years in the reservoir with oil and gas. When a hydrocarbon reservoir is infiltrated by a production w...Produced water (PW) is the largest waste stream in the oil and gas industry. Water remains trapped for millions of years in the reservoir with oil and gas. When a hydrocarbon reservoir is infiltrated by a production well, the produced fluids commonly contain water. The understanding of this water’s constituents and volumes is vital for the sustainable continuity of production operations, as PW has a number of negative impacts on the infrastructure integrity of the operation. On the other hand, PW can be an alternative source of irrigation water as well as of industrial salt. Interestingly, both the quantity as well as the quality of PW do not remain constant but can vary, both progressively and erratically, even over short periods of time. This paper discusses such a situation of variable PW in an oil and gas operation in the State of Kuwait.展开更多
A new high spectral resolution crystal spectrometer is designed to measure very low emissive X-ray spectra of laser-produced plasma in 0.5-0.9 nm range. A large open aperture (30 ×20 (mm)) mica (002) spheri...A new high spectral resolution crystal spectrometer is designed to measure very low emissive X-ray spectra of laser-produced plasma in 0.5-0.9 nm range. A large open aperture (30 ×20 (mm)) mica (002) spherically bent crystal with curvature radius R = 380 mm is used as dispersive and focusing element. The imaging plate is employed to obtain high spectral resolution with effective area of 30 × 80 (mm). The long designed path of the X-ray spectrometer beam is 980 mm from the source to the detector via the crystal. Experiment is carried out at a 20-J laser facility. X-ray spectra in an absolute intensity scale is obtained from Al laserproduced plasmas created by laser energy of 6.78 J. Samples of spectra obtained with spectral resolution of up to E/△E - 1500 are presented. The results clearly show that the device is good to diagnose laser high-density plasmas.展开更多
Oil-water separation for produced water (PW) originating from an oil extraction site in South Kuwait was carried out using bleached, esterified cellulosic material from used coffee grounds. Thereafter, earth-alkaline ...Oil-water separation for produced water (PW) originating from an oil extraction site in South Kuwait was carried out using bleached, esterified cellulosic material from used coffee grounds. Thereafter, earth-alkaline metal ions, specifically calcium ions, of the de-oiled PW were removed by precipitation with sodium carbonate to give access to pure sodium chloride as industrial salt from the remaining PW. While the purity of the precipitated calcium carbonate (CaCO3) depends on the precipitation conditions, CaCO3 of up to 95.48% purity can be obtained, which makes it a salable product. The precipitation of CaCO3 decreases the amount of calcium ions in PW from 11,300 ppm to 84 ppm.展开更多
Produced water from an oil extraction site in South Kuwait was sampled after primary oil – water separation had been carried out. The produced water was filtered through a mixture of activated charcoal and esterified...Produced water from an oil extraction site in South Kuwait was sampled after primary oil – water separation had been carried out. The produced water was filtered through a mixture of activated charcoal and esterified cellulosic material gained from spent coffee grounds as a tertiary adsorption treatment. The earth-alkaline metal ions and heavy metals were separated from the de-oiled produced water by addition of either sodium or potassium hydroxide in the presence of carbon dioxide or by direct addition of solid sodium carbonate. The resulting filtrate gave salt of industrial purity upon selective crystallization on evaporation.展开更多
Oilfield produced water is large quantities of salty water trapped in underground formations and subsisted under high temperatures and pressures that are brought to the surface along with oil during production. Produc...Oilfield produced water is large quantities of salty water trapped in underground formations and subsisted under high temperatures and pressures that are brought to the surface along with oil during production. Produced water(PW) contains a lot of pollutants such as hydrocarbons and metals, this water must be treated before disposal. Therefore, different techniques are being used to treat produced water. Electrocoagulation is an efficient treatment technique involving the dissolution of anodes and formation of electro-coagulants, while the simultaneous generation of H_2 bubbles at the cathode leads to the pollutant removal by flotation. Electrocoagulation(EC)method is one of the most promising and widely used processes to treat oilfield produced water. In the present work, a conventional internal-loop(draught tube) airlift reactor was utilized as electrocoagulation/flotation cell for PW treatment by inserting two aluminum electrodes in the riser section of the airlift reactor. The EC airlift reactor was operated in a batch mode for the liquid phase. Different experimental parameters were studied on the oil and turbidity removal efficiencies such as current density, initial pH, electrocoagulation time, and air injection.The experimental results showed that mixing of the oil droplets in the PW was accomplished using only the liquid recirculation resulted by H_2 microbubbles generated by EC process which enhanced the oil removal. The experimental results further showed that the EC time required achieving ≥ 90% oil removal efficiency decreases from 46 to 15 min when operating current density increases from 6.8 to 45.5 mA·cm^(-2). This reactor type was found to be highly efficient and less energy consuming compared to conventional existing electrochemical cells which used mechanical agitation.展开更多
The X-ray spectrum emitted, from laser-produced plasma contains plentiful information. X-ray spectrometer is a powerful tool for plasma diagnosis and studying the information and evolution of the plasma. X-ray concave...The X-ray spectrum emitted, from laser-produced plasma contains plentiful information. X-ray spectrometer is a powerful tool for plasma diagnosis and studying the information and evolution of the plasma. X-ray concave (elliptical) curved crystals analyzer was designed and manufactured to investigate the properties of laser-produced plasma. The experiment was carried out on Mianyang Xingguang-Ⅱ Facility and aimed at investigating the characteristics of a high density iron plasma. Experimental results using KAP, LIF, PET, and MICA curved crystal analyzers are described, and the spectra of Au, Ti laser-produced plasma are shown. The focusing crystal analyzer clearly gave an increase in sensitivity over a flat crystal.展开更多
The selection of an apt technology for the treatment of Oilfield Produced Water(OFPW)depends mainly on the quality of OFPW and methods of pre-and post-treatment processes.The most challenging part of the OFPW treatmen...The selection of an apt technology for the treatment of Oilfield Produced Water(OFPW)depends mainly on the quality of OFPW and methods of pre-and post-treatment processes.The most challenging part of the OFPW treatment process is the removal of Suspended Solid(SS),Oil&Grease(O&G)and dissolved organics.SS and O&G pose an acute problem to the membrane filtration system by fouling the membrane surface which increases operation&maintenance costs and decreases the life of the membrane.Fouling of the membrane surface is mainly attributed to the presence of low molecular weight aromatic compounds and naphthenic acids in the suspended and dissolved organic compounds.Thus,the removal of these suspended and dissolved organic compounds before membrane filtration proffers a challenge to the researchers.In this research,bioremediation process has been applied to remove the organic compounds and the performance and fouling behaviour of hollow fibre Microfiltration(MF),Ultrafiltration(UF)and Nanofiltration(NF)membranes after the bioremediation process has been analyzed in detail.The level of toxicity was determined by comparing the pollutants with the safe discharge limit for disposal into the environment set by Central Pollution Control Board(CPCB),India.The research presents its novelty by using a hydrocarbon-degrading bacteria,Pseudomonas aeruginosa for the Reduction of Organic Loads(ROL)from OFPW of Moran oil field of Upper Assam as a pre-treatment to membrane filtration.The Total Sum Corrected Area(TSCA)method through chromatographic analyses was used for this.The organic loads removal from OFPW by the TSCA method was found to be 67-100%,100%and 100%after 7,14 and 21 days of bioremediation respectively.The major parameters in feed OFPW of Moran oil field were found to be pH(7.5-9.3),Total Dissolved Solid(TDS)(1.79-4.75)ppt,O&G(1.78-2.8)ppt,Salinity(2.94-6.98)ppt,Chloride(Cl^(-))(1.6-3.86)ppt,Bicarbonate(HCO_(3)^(-))(2.89-4.03)ppt.It was observed that the ranges of pollutants removal by NF was highest such as TDS(26-86%),sa展开更多
The rapidly increasing implementations of oilfield technologies such as horizontal wells and multistage hydraulic fracturing,particularly in unconventional formations,have expanded the need for fresh water in many oil...The rapidly increasing implementations of oilfield technologies such as horizontal wells and multistage hydraulic fracturing,particularly in unconventional formations,have expanded the need for fresh water in many oilfield locations.In the meantime,it is costly for services companies and operators to properly dispose large volumes of produced water,generated annually at about 21 billion barrels in the United States alone.The high operating costs in obtaining fresh water and dealing with produced water have motivated scientists and engineers,especially in recent years,to use produced water in place of fresh water to formulate well treatment fluids.The objective of this brief review is to provide a summary of the up-to-date technologies of reusing oilfield produced water in preparations of a series of crosslinked fluids implemented mainly in hydraulic fracturing operations.The crosslinked fluids formulated with produced water include borate-and metalcrosslinked guar and derivatized guar fluids,as well as other types of crosslinked fluid systems such as crosslinked synthetic polymer fluids and crosslinked derivatized cellulose fluids.The boratecrosslinked guar fluids have been successfully formulated with produced water and used in oilfield operations with bottomhole temperatures up to about 250F.The produced water sources involved showed total dissolved solids(TDS)up to about 115,000 mg/L and hardness up to about 11,000 mg/L.The metal-crosslinked guar fluids prepared with produced water were successfully used in wells at bottomhole temperatures up to about 250F,with produced water TDS up to about 300,000 mg/L and hardness up to about 44,000 mg/L.The Zr-crosslinked carboxymethyl hydroxypropyl guar(CMHPG)fluids have been successfully made with produced water and implemented in operations with bottomhole temperatures at about 250tF,with produced water TDS up to about 280,000 mg/L and hardness up to about 91,000 mg/L.In most of the cases investigated,the produced water involved was either untreated,or the treatments展开更多
Due to the severe restrictions imposed by legislative frameworks, the removal of polyacrylamide(PAM) rapidly and effectively from produced wastewater in offshore oilfields before discharge is becoming an urgent challe...Due to the severe restrictions imposed by legislative frameworks, the removal of polyacrylamide(PAM) rapidly and effectively from produced wastewater in offshore oilfields before discharge is becoming an urgent challenge. In this study, a novel advanced oxidation process based on plasma operated in the gas–liquid interface was used to rapidly decompose PAM, and multiple methods including viscometry, flow field-flow fractionation multi-angle light scattering, UV–visible spectroscopy, and attenuated total reflectanceFourier transform infrared spectroscopy were used to characterize the changes of PAM.Under a discharge voltage of 25 kV and pH 7.0, the PAM concentration decreased from 100 to 0 mg/L within 20 min and the total organic carbon(TOC) decreased from 49.57 to1.23 mg/L within 240 min, following zero-order reaction kinetics. Even in the presence of background TOC as high as 152.2 mg/L, complete removal of PAM(100 mg/L) was also achieved within 30 min. The biodegradability of PAM improved following plasma treatment for 120 min. Active species(such as O3 and H2O2) were produced in the plasma. Hydroxyl radical was demonstrated to play an important role in the degradation of PAM due to the inhibitory effect observed after the addition of an ·OH scavenger, Na2CO3. Meanwhile, the release of ammonia and nitrate nitrogen confirmed the cleavage of the acylamino group.The results of this study demonstrated that plasma, with its high efficiency and chemicalfree features, is a promising technology for the rapid removal of PAM.展开更多
基金supported by the Water Pollution Control and Management Project,China(No. 2009ZX07208)the Ministry of Science and Technology,China,for partially funding this study
文摘Treatment of oilfield produced water was investigated using an anaerobic process coupled with micro-electrolysis (ME), focusing on changes in chemical oxygen demand (COD) and biodegradability. Results showed that COD exhibited an abnormal change in the single anaerobic system in which it increased within the first 168 hr, but then decreased to 222 mg/L after 360 hr. The biological oxygen demand (five-day) (BOD5)/COD ratio of the water increased from 0.05 to 0.15. Hydrocarbons in the wastewater, such as pectin, degraded to small molecules during the hydrolytic acidification process. Comparatively, the effect of ME was also investigated. The COD underwent a slight decrease and the BOD5/COD ratio of the water improved from 0,05 to 0.17 after ME. Removal of COD was 38.3% under the idealized ME conditions (pH 6.0), using iron and active carbon (80 and 40 g/L, respectively). Coupling the anaerobic process with ME accelerated the COD removal ratio (average removal was 53.3%). Gas chromatography/mass spectrometry was used to analyze organic species conversion. This integrated system appeared to be a useful option for the treatment of water produced in oilfields.
基金supported by the National Key R&D Program of China (2016YFA0600203)the National High-Tech Research and Development Program (2011AA12A104)External Cooperation Program of the Chinese Academy of Sci-ences (Grant No. GJHZ1507)
文摘1.The need for global carbon monitoring from space and the TanSat mission Global warming is a major problem,for which carbon dioxide(CO2 )is the main greenhouse gas involved in heating the troposphere.However,the poor availability of global CO2 measurements makes it difficult to estimate CO2 emissions accurately.
基金Supported by the National Natural Science Foundation of China (No.59978020).
文摘The biological aerated filter (BAF) was used to treat the oil-field produced water. The removal efficiency for oil, COD, BOD and suspended solids (SS) was 76.3%-80.3%, 31.6%-57.9%, 8.6.3%-96.3% and76.4%--82.7%, respectively when the hydraulic loading rates varied from 016m·h^-1 to 1.4m·h^-1. The greatest partof removal, for example more than 80% of COD removal, occurred on the top 100cm of the media in BAF. The kinetic .performance of BAF indicated that the relationship of BOD removal efficiency with the hydraulic loadingrates, in biological aerated filters could be described by c1/c1=l-exp(-2.44/L^0.59). This equation could be used topredict the B OD.removal efficiency at different hydraulic loading rates.
文摘The emulsion stability of oilfield produced water is related to the oil-water interfacial film strength and the zeta potential of the oil droplets. We investigated the effects of water treatment agents (corrosion inhibitor SL-2, scale inhibitor HEDP, germicide 1227, and flocculant polyaluminium chloride PAC) on the stability of oilfield produced water. The influence of these treatment agents on oil-water interfacial properties and the mechanism of these agents acting on the oilfield produced water were studied by measuring the interfacial shear viscosity, interfacial tension and zeta electric potential. The results indicated that the scale inhibitor HEDP could increase the oil-water interfacial film strength, and it could also increase the absolute value of the zeta potential of oil droplets. HEDP played an important role in the stability of the emulsion. Polyaluminum chloride (PAC) reduced the stability of the emulsion by considerably decreasing the absolute value of the zeta potential of oil droplets. Corrosion inhibitor SL-2 and germicide 1227 could decrease the oil-water interfacial tension, whereas they had little influence on oil-water interfacial shear viscosity and oil-water interfacial electricity properties.
文摘During the start-up and unstable combustion periods,even the state-of-the-art incinerators emit polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/PCDF) in stack gases at concentrations that are up to 1000 times higher than normal operation. Therefore,incinerators and other sources with variation of PCDD/PCDF release into air cannot be reliably monitored by the conventional short-term sampling that covers only 0.1%to 0.2%of the yearly operating time.A more comprehensive monitoring regime is required.This paper describes different applications of continuous PCDD/PCDF sampling in some European countries.The cases demonstrate that flexible regimes for continuous sampling can be crafted and applied by governments or regional/local authorities.Such regimes range from a countrywide,continuous requirement for selected facility types(e.g.,waste incinerators) to a facility-specific regime that applies,for example,to new facilities for a defined time period until the facility has demonstrated continuous compliance with regulatory limits. Countries implementing the Stockholm Convention are suggested to evaluate in their Best available technology/Best environmental practice(BAT/BEP) activities the usefulness of long-term sampling by,for example,designating institutes related to the environmental ministry or regional authorities to supervise long-term sampling regimes at relevant facilities in their country/areas,beginning with priority sources(e.g.,facilities used for destruction of persistent organic pollutants(POPs) or hazardous waste processing) . This paper presents and discusses the results of the AMESA long-term monitoring system having demonstrated that in addition to PCDD/PCDF all other unintentionally produced POPs listed in the Stockholm Convention could be supervised.
基金Deutsche Forschung Gemainschaft(Ec/201/1-5)Deutsches Zentrum fuer Luft und Raumfahrt(50WM0058).
文摘The interplay between chemistry and interfacial-tension-driven hydrodynamic instabilities has been studied experimentally. The system on hand consists of two immiscible liquids separated along an initially plane interface at which an interfacial reaction takes place to produce in situ a surfactant. It is identified that the dynamics of the system depends on the orientation of the Hele-Shaw cell with respect to the vector of gravity. If the nele-Shaw cell is placed vertically, Marangoni cells with vigorous convection develop in both phases along a nearly planar interface. However, if the Hele-Shaw cell is tilted off the gravity, the instabilities in the system are characterized by the large scale interracial deformation with a spatio-temporal periodicity together with the chemo-Marangoni convection. The focus is on the exploration of the transition from the cellular mode to the large scale interfacial deformation.
文摘Seventy-nine strains of bioflocculant-producing bacteria were isolated from 3 activated sludge samples. Among them, strain MYC was found to have the highest and stable flocculating rate for both kaolin clay suspension and oil-field produced water. The bacterial strain was identified as Klebsiella sp. MYC according to its morphological and biochemical characteristics and 16SrDNA sequence. The optimal medium for bioflocculant production by this bacterial strain was composed of cane sugar 20 g L^-1, KH2PO4 2 g L^-1, K2HPO4 5 g L^- 1, ( NH4)2SO4 0.2 g L^-1, urea 0.5 g L^- 1 and yeast extract 0.5 g L^- 1, the initial pH being 5.5. When the suspension of kaolin clay was treated with0.5% of Klebsiella sp. MYC culture broth, the flocculating rate reached more than 90.0% in the presence of 500mg L^-1 CaCI2, while the flocculating rate for oil-field produced water was near 80.0% in a pH range of 7.0 - 9.0 with the separation of oil and suspended particles from the oil-field produced water under similar conditions. The environment-friendly nature of the bioflocculant and high flocculating rate of the strain make the bioflocculant produced by Klebsiella sp. MYC an attractive bioflocculant in oil-field produced water treatment.
基金The National Basic Research Program (973) of China (No. 2004CB418505)
文摘Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only few were implemented on an industrial scale. Among those techniques, turbulence promoter can be more simple and effective in overcoming membrane fouling and enhancing membrane flux. As for the result that turbulence promoter increase fluid velocity, wall shear rates and produce secondary flows or instabilities, the influence of turbulence promoter was investigated on permeate flux during produced water ultrafiltration and the potential application of this arrangement for an industrial development. Experimental investigations were performed on 100 KDa molecular weight cut-off PVDF single-channel tubular membrane module using four kinds of turbulence promoters. It is observed that the significant flux enhancement in the range of 83%--164% was achieved while the hydraulic dissipated power per unit volume of permeate decreased from 31%--42%, which indicated that the using of turbulence promoter is more efficient than operation without the turbulence promoter. The effects of transmembrane pressure and cross-flow velocity with and without turbulence promoter were studied as well. Among the four kinds of turbulence promoters, winding inserts with 20.0 mm pitch and 1.0 mm wire diameter showed better performances than the others did.
基金funded by the National Science and Technology Major Project (2011ZX05060-005 2009ZX05039-003)
文摘To reveal the geochemical characters of water coproduced with coalbed gas and shallow groundwater,water samples were collected from 12 wells of coalbed methane and 7 wells of shallow groundwater.The pH,CODMn,fCO2,total dissolved solids (TDS),total hardness,and concentrations of metasilicic acid,sodium and kalium,calcium ion,magnesium ion,ammonium iron,bicarbonate ion,carbonate,chloride,sulfate ion,nitrate ion,fluoride,lithium,zinc,nickel,manganese,iron,boron,barium,etc.of the samples were measured.Research results showed the following:(1) Concentrations of TDS,chloride,fluoride,sodium and kalium,ammonium,iron,and barium in the water coproduced with coalbed gas exceeded the national standards of China; however,physical,chemical,and biological properties of shallow groundwater could meet the national standard.(2) The water produced from coalbed contained mainly Na-Cl·HCO3,with average TDS of 4588.5 ppm,whereas shallow groundwater contained a mixture of chemicals including Na.Mg.Ca-HCO3·SO4 and Na.Mg-HCO3·SO4,with average TDS of 663.8 ppm.(3) In general,it was observed that bicarbonate and sodium accumulated in a reducing environment and deeper system,while depletion of hydrogen ions and dissolution of sulfate,calcium,and magnesium occurred in a redox environment and shallow system.(4) Sodium and kalium,ammonium,chloride,and bicarbonate ions were the main ions found in the study area.
文摘Produced water (PW) is the largest waste stream in the oil and gas industry. Water remains trapped for millions of years in the reservoir with oil and gas. When a hydrocarbon reservoir is infiltrated by a production well, the produced fluids commonly contain water. The understanding of this water’s constituents and volumes is vital for the sustainable continuity of production operations, as PW has a number of negative impacts on the infrastructure integrity of the operation. On the other hand, PW can be an alternative source of irrigation water as well as of industrial salt. Interestingly, both the quantity as well as the quality of PW do not remain constant but can vary, both progressively and erratically, even over short periods of time. This paper discusses such a situation of variable PW in an oil and gas operation in the State of Kuwait.
基金supported by the National Natural Science Foundation of China under Grant No.10576041
文摘A new high spectral resolution crystal spectrometer is designed to measure very low emissive X-ray spectra of laser-produced plasma in 0.5-0.9 nm range. A large open aperture (30 ×20 (mm)) mica (002) spherically bent crystal with curvature radius R = 380 mm is used as dispersive and focusing element. The imaging plate is employed to obtain high spectral resolution with effective area of 30 × 80 (mm). The long designed path of the X-ray spectrometer beam is 980 mm from the source to the detector via the crystal. Experiment is carried out at a 20-J laser facility. X-ray spectra in an absolute intensity scale is obtained from Al laserproduced plasmas created by laser energy of 6.78 J. Samples of spectra obtained with spectral resolution of up to E/△E - 1500 are presented. The results clearly show that the device is good to diagnose laser high-density plasmas.
文摘Oil-water separation for produced water (PW) originating from an oil extraction site in South Kuwait was carried out using bleached, esterified cellulosic material from used coffee grounds. Thereafter, earth-alkaline metal ions, specifically calcium ions, of the de-oiled PW were removed by precipitation with sodium carbonate to give access to pure sodium chloride as industrial salt from the remaining PW. While the purity of the precipitated calcium carbonate (CaCO3) depends on the precipitation conditions, CaCO3 of up to 95.48% purity can be obtained, which makes it a salable product. The precipitation of CaCO3 decreases the amount of calcium ions in PW from 11,300 ppm to 84 ppm.
文摘Produced water from an oil extraction site in South Kuwait was sampled after primary oil – water separation had been carried out. The produced water was filtered through a mixture of activated charcoal and esterified cellulosic material gained from spent coffee grounds as a tertiary adsorption treatment. The earth-alkaline metal ions and heavy metals were separated from the de-oiled produced water by addition of either sodium or potassium hydroxide in the presence of carbon dioxide or by direct addition of solid sodium carbonate. The resulting filtrate gave salt of industrial purity upon selective crystallization on evaporation.
文摘Oilfield produced water is large quantities of salty water trapped in underground formations and subsisted under high temperatures and pressures that are brought to the surface along with oil during production. Produced water(PW) contains a lot of pollutants such as hydrocarbons and metals, this water must be treated before disposal. Therefore, different techniques are being used to treat produced water. Electrocoagulation is an efficient treatment technique involving the dissolution of anodes and formation of electro-coagulants, while the simultaneous generation of H_2 bubbles at the cathode leads to the pollutant removal by flotation. Electrocoagulation(EC)method is one of the most promising and widely used processes to treat oilfield produced water. In the present work, a conventional internal-loop(draught tube) airlift reactor was utilized as electrocoagulation/flotation cell for PW treatment by inserting two aluminum electrodes in the riser section of the airlift reactor. The EC airlift reactor was operated in a batch mode for the liquid phase. Different experimental parameters were studied on the oil and turbidity removal efficiencies such as current density, initial pH, electrocoagulation time, and air injection.The experimental results showed that mixing of the oil droplets in the PW was accomplished using only the liquid recirculation resulted by H_2 microbubbles generated by EC process which enhanced the oil removal. The experimental results further showed that the EC time required achieving ≥ 90% oil removal efficiency decreases from 46 to 15 min when operating current density increases from 6.8 to 45.5 mA·cm^(-2). This reactor type was found to be highly efficient and less energy consuming compared to conventional existing electrochemical cells which used mechanical agitation.
基金This work was supported by the National "863" Project of China. S. Xiao's e-mail is xiaoshali@cqu.edu.cn.
文摘The X-ray spectrum emitted, from laser-produced plasma contains plentiful information. X-ray spectrometer is a powerful tool for plasma diagnosis and studying the information and evolution of the plasma. X-ray concave (elliptical) curved crystals analyzer was designed and manufactured to investigate the properties of laser-produced plasma. The experiment was carried out on Mianyang Xingguang-Ⅱ Facility and aimed at investigating the characteristics of a high density iron plasma. Experimental results using KAP, LIF, PET, and MICA curved crystal analyzers are described, and the spectra of Au, Ti laser-produced plasma are shown. The focusing crystal analyzer clearly gave an increase in sensitivity over a flat crystal.
文摘The selection of an apt technology for the treatment of Oilfield Produced Water(OFPW)depends mainly on the quality of OFPW and methods of pre-and post-treatment processes.The most challenging part of the OFPW treatment process is the removal of Suspended Solid(SS),Oil&Grease(O&G)and dissolved organics.SS and O&G pose an acute problem to the membrane filtration system by fouling the membrane surface which increases operation&maintenance costs and decreases the life of the membrane.Fouling of the membrane surface is mainly attributed to the presence of low molecular weight aromatic compounds and naphthenic acids in the suspended and dissolved organic compounds.Thus,the removal of these suspended and dissolved organic compounds before membrane filtration proffers a challenge to the researchers.In this research,bioremediation process has been applied to remove the organic compounds and the performance and fouling behaviour of hollow fibre Microfiltration(MF),Ultrafiltration(UF)and Nanofiltration(NF)membranes after the bioremediation process has been analyzed in detail.The level of toxicity was determined by comparing the pollutants with the safe discharge limit for disposal into the environment set by Central Pollution Control Board(CPCB),India.The research presents its novelty by using a hydrocarbon-degrading bacteria,Pseudomonas aeruginosa for the Reduction of Organic Loads(ROL)from OFPW of Moran oil field of Upper Assam as a pre-treatment to membrane filtration.The Total Sum Corrected Area(TSCA)method through chromatographic analyses was used for this.The organic loads removal from OFPW by the TSCA method was found to be 67-100%,100%and 100%after 7,14 and 21 days of bioremediation respectively.The major parameters in feed OFPW of Moran oil field were found to be pH(7.5-9.3),Total Dissolved Solid(TDS)(1.79-4.75)ppt,O&G(1.78-2.8)ppt,Salinity(2.94-6.98)ppt,Chloride(Cl^(-))(1.6-3.86)ppt,Bicarbonate(HCO_(3)^(-))(2.89-4.03)ppt.It was observed that the ranges of pollutants removal by NF was highest such as TDS(26-86%),sa
文摘The rapidly increasing implementations of oilfield technologies such as horizontal wells and multistage hydraulic fracturing,particularly in unconventional formations,have expanded the need for fresh water in many oilfield locations.In the meantime,it is costly for services companies and operators to properly dispose large volumes of produced water,generated annually at about 21 billion barrels in the United States alone.The high operating costs in obtaining fresh water and dealing with produced water have motivated scientists and engineers,especially in recent years,to use produced water in place of fresh water to formulate well treatment fluids.The objective of this brief review is to provide a summary of the up-to-date technologies of reusing oilfield produced water in preparations of a series of crosslinked fluids implemented mainly in hydraulic fracturing operations.The crosslinked fluids formulated with produced water include borate-and metalcrosslinked guar and derivatized guar fluids,as well as other types of crosslinked fluid systems such as crosslinked synthetic polymer fluids and crosslinked derivatized cellulose fluids.The boratecrosslinked guar fluids have been successfully formulated with produced water and used in oilfield operations with bottomhole temperatures up to about 250F.The produced water sources involved showed total dissolved solids(TDS)up to about 115,000 mg/L and hardness up to about 11,000 mg/L.The metal-crosslinked guar fluids prepared with produced water were successfully used in wells at bottomhole temperatures up to about 250F,with produced water TDS up to about 300,000 mg/L and hardness up to about 44,000 mg/L.The Zr-crosslinked carboxymethyl hydroxypropyl guar(CMHPG)fluids have been successfully made with produced water and implemented in operations with bottomhole temperatures at about 250tF,with produced water TDS up to about 280,000 mg/L and hardness up to about 91,000 mg/L.In most of the cases investigated,the produced water involved was either untreated,or the treatments
基金supported by National Natural Scientific Foundation of China(No.2159081)the Ministry of Science and Technology,People’s Republic of China(No.2012AA063401)
文摘Due to the severe restrictions imposed by legislative frameworks, the removal of polyacrylamide(PAM) rapidly and effectively from produced wastewater in offshore oilfields before discharge is becoming an urgent challenge. In this study, a novel advanced oxidation process based on plasma operated in the gas–liquid interface was used to rapidly decompose PAM, and multiple methods including viscometry, flow field-flow fractionation multi-angle light scattering, UV–visible spectroscopy, and attenuated total reflectanceFourier transform infrared spectroscopy were used to characterize the changes of PAM.Under a discharge voltage of 25 kV and pH 7.0, the PAM concentration decreased from 100 to 0 mg/L within 20 min and the total organic carbon(TOC) decreased from 49.57 to1.23 mg/L within 240 min, following zero-order reaction kinetics. Even in the presence of background TOC as high as 152.2 mg/L, complete removal of PAM(100 mg/L) was also achieved within 30 min. The biodegradability of PAM improved following plasma treatment for 120 min. Active species(such as O3 and H2O2) were produced in the plasma. Hydroxyl radical was demonstrated to play an important role in the degradation of PAM due to the inhibitory effect observed after the addition of an ·OH scavenger, Na2CO3. Meanwhile, the release of ammonia and nitrate nitrogen confirmed the cleavage of the acylamino group.The results of this study demonstrated that plasma, with its high efficiency and chemicalfree features, is a promising technology for the rapid removal of PAM.