Molecular transformation of dissolved organic matter in refinery wastewaters: Characterized by FT-ICR MS coupled with electrospray ionization and atmospheric pressure photoionization

Dissolved organic matter(DOM)in refinery wastewater is an extremely complex mixture of various organic compounds.Using mass spectrometry,it is impossible to characterize all of the DOM molecules with only one ionization source.In this study,negative-ion,electrospray ionization(ESI),positive-ion ESI,and positive-ion atmospheric pressure photoionization(APPI)were coupled with Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)to analyze the molecular composition of DOM in a refinery wastewater stream during the treatment process.There were obvious differences in the heteroatom composition,number of DOM constituents,and chemical properties in refinery wastewater under the three ionization modes.Acidic CHO and CHOS compounds detected by(+)ESI,basic CHN and CHON compounds detected by(þ)ESI,and hydrocarbons detected by(+)APPI were analyzed to determine the molecular transformations that occurred during treatment.In an anaerobic biological treatment process,acidic CHO and CHOS compounds with a high oxygen content were preferentially removed,and acidic CHO and CHOS compounds with a low oxygen content were produced.In an aerobic biological process,acidic CHO and CHOS compounds with a low oxygen content were preferentially removed,and acidic CHO and CHOS compounds with a high oxygen content were produced.The whole biological treatment process has a poor removal efficiency for CHN and CHON compounds,and hydrocarbons.An activated carbon(AC)adsorption process removed different heteroatom compounds mainly with a low oxygen content for acidic and basic compounds.The transformation mechanism of CHO and CHOS compounds in the biological treatment process was analyzed by the Kendrick mass defect(KMD)theory and a mass difference network analysis.In the anaerobic process,large amounts of oxygenated CHO and CHOS compounds were degraded by decarboxylation,deoxydation,demethoxylation,and dehydration reactions,and converted to lower oxygen content compounds.In the aerobic processes,these low oxygen CHO and CHOS compounds mainly underwent carboxylation and oxidation reactions.This study determined the transformation characteristics and mechanisms of different types of organic compounds in refinery wastewater during the treatment process.The results provide guidance for the design and optimization of technologies for refinery wastewater treatment.

An alternative treatment process for upgrade of petroleum refinery wastewater using electrocoagulation

An electrocoagulation treatment process was developed for treatment and upgrade of petroleum refinery effluent （wastewater）, instead of the conventional methods, which can consume higher amounts of chemicals and produce larger amounts of sludge. The effect of the operation parameters, such as current density, initial pH, anode material, anode dissolution, energy consumption and electrolysis time, on treatment efficiency was investigated. The experimental results showed that the effluent can be effectively treated under optimal conditions. Fourier transform infrared （FTIR） analysis of the effluent, and scanning electron microscopy （SEM） coupled with energy dispersive analysis of X-rays （EDAX） of the sludge produced, revealed that the unwanted pollutants can be eliminated. The electrocoagulation treatment process was assessed by using the removal efficiency of chemical oxygen demand （COD）, total suspended solids （TSS）, and the general physicochemical characteristics of wastewater, and the results showed that the electrocoagulation is an efficient process for recycling of petroleum wastewater; it is faster and provides better quality of treated water than the conventional methods.

Radial Basis Function Neural Networks-Based Modeling of the Membrane Separation Process: Hydrogen Recovery from Refinery Gases

Membrane technology has found wide applications in the petrochemical industry, mainly in the purification and recovery of the hydrogen resources. Accurate prediction of the membrane separation performance plays an important role in carrying out advanced process control （APC）. For the first time, a soft-sensor model for the membrane separation process has been established based on the radial basis function （RBF） neural networks. The main performance parameters, i.e, permeate hydrogen concentration, permeate gas flux, and residue hydrogen concentration, are estimated quantitatively by measuring the operating temperature, feed-side pressure, permeate-side pressure, residue-side pressure, feed-gas flux, and feed-hydrogen concentration excluding flow structure, membrane parameters, and other compositions. The predicted results can gain the desired effects. The effectiveness of this novel approach lays a foundation for integrating control technology and optimizing the operation of the gas membrane separation process.

Treatment of Slightly Polluted Wastewater in an Oil Refinery Using a Biological Aerated Filter Process

The slightly polluted wastewater from oil refinery contains some COD, oil pollutants and suspended solids （SS）. A small-scale fixed film biological aerated filter （BAF） process was used to treat the wastewater. The influences of hydraulic retention time （HRT）, air/water volume flow ratio and backwashing cycle on treatment efficiencies were investigated. The wastewater was treated by the BAF process under optimal conditions： the HRT of 1.0 h, the air/water volume flow ratio of about 5 ： 1 and the backwashing cycle of every 4-7 days. The results showed that the average removal efficiency of COD, oil pollutants and SS was 84.5%, 94.0% and 83.4%, respectively. And the average effluent concentration of COD, oil pollutants and SS was 12.5, 0.27, 14.5 mg·L^-1, respectively. The experimental results demonstrated that the BAF process is a suitable and highly efficient method to treat the wastewater.

Application of organic polymeric flocculants in centrifugal dewa-tering of oil refinery sludge

In order to evaluate the applicability of the organic polymeric flocculants(OPF) in the treatment of oil refinery sludge, experiments were conducted to show that OPF have better performance of flocculation than inorganic flocculants. Both the anionic and cationic OPF have satisfactory flocculation efficiency in oil sludge treatment, but the latter are more cost efficient. Among the over 20 types of flocculants tested, 2 OPF(CPAM 2 and HPAM 2) were selected as the treatment agents, based on their good treatment performances, oil resistance and economic feasibility. It was demonstrated in the industrial scale centrifugal dewatering experiments that the application of either CPAM 2 or HPAM 2 could achieve high treatment efficiency of the oil sludge dewatering and reduce the COD of centrifugal liquid to less than 1000 mg/L.

Pretreatment of super viscous oil wastewater and its application in refinery

Wastewater from super viscous oil processing cannot be effectively treated by conventional wastewater treatment plants in refineries because of its high concentration of various organic pollutants. In order to resolve this problem, a number of investigations were conducted in our work to understand the physicochemical properties, sedimentation, demulsification and pretreatment of such super viscous oil refinery wastewater. The results showed that the key issues for pretreatment of this wastewater were： （1） Optimized process parameters were used in the sedimentation and demulsification processes for oil removal to effectively recover oil and remove scum from wastewater; （2） A suitable flocculation process was selected to minimize oil, suspended solids （SS） and chemical oxygen demand （CODcr）. A pretreatment process including three continuous steps： oil removal by sedimentation, oil removal by demulsification, and flotation separation, was proposed and applied in Liaohe Petrochemical Company, PetroChina and the oil content in effluents was less than 200 mg/L and CODcr less than 2,500 mg/L, which completely met the requirement for influent of the conventional wastewater treatment plant, and the recovered super viscous oil reached 5,873 tons in the initial year in Liaohe Petrochemical Company, PetroChina.

Efficient ozonation of reverse osmosis concentrates from petroleum refinery wastewater using composite metal oxideloaded alumina

Novel Mn–Fe–Mg-and Mn–Fe–Ce-loaded alumina（Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3） were developed to catalytically ozonate reverse osmosis concentrates generated from petroleum refinery wastewaters（PRW-ROC）. Highly dispersed 100–300-nm deposits of composite multivalent metal oxides of Mn（Mn^2＋）, Mn^3＋,and Mn^4＋, Fe（Fe^2＋）and Fe^3＋ and Mg（Mg^2＋）, or Ce（Ce^4＋） were achieved on Al2O3 supports. The developed Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3 exhibited higher catalytic activity during the ozonation of PRW-ROC than Mn–Fe/Al2O3, Mn/Al2O-3, Fe/Al2O3, and Al2O3. Chemical oxygen demand removal by Mn–Fe–Mg/Al2O3-or Mn–Fe–Ce/Al2O3-catalyzed ozonation increased by 23.9% and23.2%, respectively, in comparison with single ozonation.Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3 notably promoted áOH generation and áOH-mediated oxidation. This study demonstrated the potential use of composite metal oxide-loaded Al2O3 in advanced treatment of bio-recalcitrant wastewaters.

Hydrolysis and acidification of activated sludge from a petroleum refinery

The cost-effective treatment of activated sludge that is generated by refining petroleum is a challenging industrial problem.In this study, semi-continuous stirred tank reactors(CSTRs) containing petroleum refinery excess activated sludge(PREAS)were used to comparatively investigate hydrolysis and acidification rates, after the addition of heneicosane(C_(21)H_(44))(R1)and 1-phenylnaphthalene(C16 H12)(R2) to different and individual reactors. Operation of the reactors using a sludge retention time(SRT) of 6 days and a pH of 5.0, resulted in the maintenance of stable biological activity as determined by soluble chemical oxygen demand(SCOD), volatile fatty acids(VFAs) production and oil removal efficiency. The optimum conditions for hydrogen production include a SRT of 8 days, at pH 6.5. Under these conditions, hydrogen production rates in the control containing only PREAS were 1567 mL/L(R0), compared with 1365 mL/L in Rl and 1454 mL/L-PREAS in R2.Coprothermobacter, Fervidobacterium, Caldisericum and Tepidiphilus were the dominant bacterial genera that have the potential to degrade petroleum compounds and generate VFAs. This study has shown that high concentrations of heneicosane and 1-phenylnaphthalene did not inhibit the hydrolytic acidification of PREAS.

Leaching behavior of zinc and copper from zinc refinery residue and filtration performance of pulp under the hydrothermal process

This study aims to investigate the leaching behavior and filtration performance of zinc refinery residue under hydrothermal conditions. The relationships between the structure and morphology of silicon in the leaching residue and the pulp filtration performance were explored by determining the pulp filtration speed, analyzing quantitatively the silicon content in the leachate, and characterizing the leaching residue structure. The results show that hydrothermal leaching induces the coagulation–hydrolysis of the silicon in solution, consequently altering the microstructure of the leaching residue, and that silicon oxygen tetrahedra([SiO_4]^(4-)) form the main skeleton structure of the residue. The results obtained also show that the leaching rates of zinc and copper are 98.1% and 98.7%, respectively, and that the filtration speed is 526.32 L/(m^2·h) under the conditions of sulfuric acid concentration of 140 g/L, leaching temperature of 160°C, leaching time of 3.0 h, oxygen partial pressure of 0.75 MPa, stirring speed of 600 r/min, and a liquid-to-solid ratio of 10 mL/g.

Preliminary Discussion on the Construction and Development of Modern Refinery in China

Sustainable development of refinery is an important problem that refining industry faces in the21st Century. The situation and challenges in front of refining industry are analyzed and illustrated byexamples in this paper. It is also recognized that large-scale, clean, light-oriented and integrated refinery isthe mode of development in future, and also an important measure for the sustainable development ofpetroleum resource.

Waveband Selection with Equivalent Prediction Performance for FTIR/ATR Spectroscopic Analysis of COD in Sugar Refinery Waste Water

The level of chemical oxygen demand(COD)is an important index to evaluate whether sewage meets the discharge requirements,so corresponding tests should be carried out before discharge.Fourier transform infrared spectroscopy(FTIR)and attenuated total reflectance(ATR)can detect COD in sewage effectively,which has advantages over conventional chemical analysis methods.And the selection of characteristic bands was one of the key links in the application of FTIR/ATR spectroscopy.In this work,based on the moving window partial least-squares(MWPLS)regression to select a characteristic wavelength,a method of equivalent wavelength selection was proposed combining with paired t-test equivalent concept.The results showed that the prediction effect of the selected wavelength was very close to that of the MWPLS method,while the number of wavelength points was much smaller.SEPAve,RP,Ave,SEPStd,and RP,Std which characterized the modeling effect were 26.3 mg L^-1,0.969,3.49 mg L^-1,and 0.006,respectively.The validation effect V-SEP and V-RP were 28.64 mg L^-1 and 0.960,respectively.The selected waveband was between 1809 cm^-1 and 1568 cm^-1.The method was of more reference value for the design of FTIR/ATR spectral instrument for COD detection.

Economic Benefits of Energy Efficiency to the Petroleum Refineries in Ghana: A Case of Tema Oil Refinery (TOR)

<span style="font-family:Verdana;">This study investigates the economic benefits of energy efficiency to petroleum refineries regarding Tema Oil Refinery (TOR), Ghana. The study explores lessons relating to the cost of production, energy recovery levels and economic fortunes of the refinery activities and designs a conceptual framework for improving the energy efficiency of Tema Oil Refinery (TOR). The study adopted a descriptive design using a quantitative approach to provide a statistical background to investigate the economic benefits of energy efficiency. A sample of 84 was adopted for study from a staff population of 520 working at Tema Oil refinery. In addition to primary data, secondary data on energy supply and consumption values from 2008 to 2019 was gathered. For the primary survey, 84 respondents were sampled from TOR and a structured questionnaire was used to retrieve information. A correlation analysis at P < 0.05 was conducted to test the relationship and significance of energy efficiency and economic benefits to the refinery. The study concludes that there is a linear trend between energy production (supply) and energy consumption. The energy generated in the entire economy of Ghana far exceeds the amount of energy consumed thus raising issues of waste or excesses that calls for better policies and management plan to improve EE. The study also identified that issues of lost energy are critical to the operations of the petroleum industry as the situation is compounded by the inability of the refineries to explore better ways to reduce and manage the waste. The study concludes that a significant and positive correlation between energy efficiency and the economic fortunes of Tema Oil Refinery is necessary for its economic fortunes. The supply of energy should have equivalence to the public consumption of energy.

A continuous-time formulation for refinery production scheduling problems involving operational transitions in mode switching

In the refinery scheduling, operational transitions in mode switching are of great significance to formulate dynamic nature of production and obtain efficient schedules. The discrete-time formulation meets two main challenges in modeling: discrete approximation of time and large size of mixed-integer linear problem(MILP).In this article, a continuous-time refinery scheduling model, which involves transitions of mode switching, is presented due to these challenges. To reduce the difficulty in solving large scale MILPs resulting from the sequencing constraints, the global event-based formulation is chosen. Both transition constraints and production transitions are introduced and the numbers of key variables and constraints in both of the discrete-time and continuous-time formulations are analyzed and compared. Three cases with different lengths of time horizons and different numbers of orders are studied to show the efficiency of the proposed model.

Rapid aerobic granulation using biochar for the treatment of petroleum refinery wastewater

Aerobic granular sludge technology has great potential for the treatment of petroleum refinery wastewater.However,strategies to shorten the granulation time and improvement the stability still need to be developed.In this work,biochar was prepared from waste petroleum activated sludge(biochar-WPS) and used in a sequencing batch reactor for the treatment of petroleum refinery wastewater.Biochar-WPS presented the surface area of 229.77 m2/g,pore volume of 0.28 cm3/g,H/C and O/C atomic ratios of 0.42 and 0.21,respectively.The porous structure and a high degree of hydrophilicity were found to facilitate microbial colonization and adhesion as well as particle aggregation.Application of biochar-WPS resulted in the formation of more substantial and stable aerobic granules(~66% of granules> 0.46 mm diameter) 15 days earlier compared with the control.The addition of biochar-WPS enhanced the average removal efficiency of chemical organic demand(~3%),oil(~4%)and total nitrogen(~10%) over the control.Increased microbial richness and diversity were observed within the formed granules and had an increased(~4%) proportion of denitrifying bacteria.These results indicate that an aerobic granulation mechanism using biochar-WPS is a feasible option for the treatment of petroleum refinery wastewater.

RHO:A Software Tool for Targeting and Design of Refinery Hydrogen Networks

Hydrogen management is important for refineries to improve their business efficiency.Various approaches such as pinch analysis and mathematical programming have been employed in the management of hydrogen system.However,it is not easy for site engineers to implement these techniques,due to the complicated procedures.At this point,it is necessary to develop a software that can implement the proposed methodologies automatically,which is really the goal of this work.The presented refinery hydrogen system optimization software(RHO)is a web based system.It is developed in the Java Web environment,where the subroutines of mathematical model developed in GAMS software can be easily called.RHO can generate graphics of both the hydrogen pinch diagram and the hydrogen distribution network.The purifiers as well as the physical distances between units are considered in the optimization model.In addition,there is a special module for the calculation of membrane separation,which is very important in the hydrogen network.The functions and the interfaces of the software are illustrated via practical cases.Case studies show the effectiveness of the RHO software.

An Assessment Study of Usefulness of Using Olive (<i>Olea europaea</i>L.) Leaves in Biomonitoring the Air Pollution near Baniyas Oil Refinery, Syria: Estimating of Total Phenolic Compounds and Lead, Copper and Manganese in Olive Leaves

The aim of this study was to estimate the total amount of phenolic compounds of olive trees leaves (Olea europaea L.) as a biomarker for the assessment of heavy metals (HMs) air pollution (Pb, Cu and Mn) in Baniyas area. Olive trees were selected as the predominant species in the study area. Samples were collected from 6 locations at different distances from the vicinity of Baniyas refinery (0.1, 0.5, 2, 4, 6, 10) Km. The control was taken from an area about 20 km from the refinery to the north-east (Al-Qardaha rural). The concentration of total phenolic compounds (TPC) during the summer was (45.6 - 70.85) mg GAE/g dw, and during winter (35.6 - 52.9) mg GAE/g dw. The concentrations of the studied HMs (Pb, Cu and Mn) in unwashed leaves during summer were (0.879 - 2.170) ppm, (0.75 - 5.21) ppm and (54.38 - 8.78) ppm respectively, whilst during the winter concentrations were (0.479 - 1.023) ppm, (1.54 - 7.29) ppm and (53.79 - 7.58) ppm respectively. The results showed significant differences in the concentration of total phenolic compounds and HMs (Pb, Cu and Mn) between sites (ANOVA), significant differences in concentrations of both total phenols and HMs (Pb and Cu) between summer and winter at all sites (t-test, p < 0.05). TPC, Pb and Mn were higher in summer in all sites than in winter. Levels of Cu were significantly higher in winter than in summer at all sites (t-test, p t-test, p < 0.05) between the concentration of total phenolic compounds and both Pb and Mn with the distance from the refinery of Baniyas. Consequently, the result of this study enhanced the usefulness of using of TPC in olive leaves as biomarker of air pollution.

Zhujiang Refinery The Largest Rare Earth Plant in South China

Zhujiang Refinery is located in the east suburb of Guangzhou city, the People’s Republic of China. Thegeographical advantage makes it convenient both in communications and in foreign trade. The refinery cov-ers an area of 15 hectares and has nearly 1000 staff members, more than 200 of whom are engineering andtechnical personnel. Established in 1966, Zhujiang Refinery has engaged in the production and scientific re-search of rare earths for more than 20 years. Having fixed assets of about RMB 20 million yuan, ZhujiangRefinery is the largest base for producing and exporting rare earths in the south of China.

Sedimentary and Geochemical Aspects of a Refinery Impacted Coastal Area: A Case Study of the Todos os Santos Bay (Bahia, Brazil)

The present study was performed in the northeast portion of the Todosos Santos Bay, Bahia State, Brazil, an area under influence of the Landulpho Alves-Mataripe (RLAM) refinery effluents. The aim of this work is to evaluate the modern sedimentary processes based on grain-size analysis, calcium carbonate and sedimentary organic matter concentration and behavior considering the possible effects of the petroleum industry’s refining on these sediments. The concentrations and variations of the three main constituents of organic matter (total organic C, total N and organic P), and the resulting elemental ratios (C/N, C/P and N/P), were studied on a seasonal spatial and temporal scale (winter 2004 and summer 2005), therefore subsidizing the environmental analysis, especially in regards to the benthic ecosystem. Fifty samples from twenty-five sampling stations were collected with a grab sampler. Well sorted sandy sediments are observed in coastal sampling stations and in the Caboto channel. The recent deposition of fine sediments was observed especially in the west and central portions of study area. However, these spots contain the highest percentages of organic material, which do not present significant seasonal and spatial variations, revealed by the values of total organic C which reach values of up to 3.1%, total N (0.01% to 0.15%) and the organic P contents that reach a maximum of 15.9 μmol·g-1. In general, the elemental ratios indicated continental organic matter inputs, probably derived from human activities.

Turbidimetric Determination of Hydrocarbon Contamination in Passaic River Sediments and Refinery Polluted Soils

A rapid method is described for the determination of petroleum hydrocarbons in soil samples. The method is based on the extraction of hydrocarbons by a solvent and the treatment of the solution with an aqueous solution of a surfactant to release the hydrocarbons to the water phase in the form of a stable emulsion. The emulsion is then utilized to measure the hydrocarbon content by turbidimetry. The effects of various operating parameters including the surfactant solution composition and time of extraction and time of mixing with the releasing solution are investigated. The stability of the emulsion was improved in acid environment containing and electrolyte. The turbidity values (T) were related with hydrocarbon concentration in the extract (C) by the following equation. Turbidity = 2.75 C + 205.7. With R2 = 0.9929. The soil hydrocarbon content (SHC) measured in μg/g can then be calculated using the formula: SHC = [Extract Vol. (mL) x C]/Sample Wt (g). The results correlated well with the results of total hydrocarbons in soils determined by standard methods. The method was applied for the estimation of hydrocarbons in Passaic river sediments taken from various locations and depths. For field work the method was used to supply data on the hydrocarbon contamination of soil samples taken within an oil refinery and a monitoring well drilled within heavy hydrocarbon waste dumping location.

Development of an Effective Method for Preventing Dust Pollution in Stone Quarries Using Petroleum Refinery Wastes

The paper presents a new method for preventing dust pollution in stone quarries using naphthenic wastes of petroleum refineries. The method is based on the use of naphthenate solutions of metals as wetting agents to minimize dust release during stone-cutting process. The studies were carried out in one of the stone quarries of the Absheron peninsula. Initial experiments were conducted by using sodium-naphthenate (RCOONa) solution from alkali wastes of refineries. The results have shown that the use of RCOONa as wetting agent considerably reduces both dust pollution and energy consumption of the used equipment, while increasing the service life of stone-cutting saw. A series of researches were carried out with cupric naphthenate (RCOOCu) to further use the obtained dust-naphthenate mixture in agriculture. The effect of various parameters on the quality of the obtained product was investigated. The investigations have revealed that maximal dust reduction and the good quality of dust-naphthenate mixture were observed with 0.13% solution of RCOOCu at 11° - 13° angle of slope and 100 - 180 rotation∕min. intensity of conveyer.