Material Balance Analysis Research Articles

Fullerene Derivatives, Preparation, Identification and Use

This article is focused on oxidation and halogenation of fullerene, identification of the prepared products and their potential application. The Fourier transform infrared (FTIR) spectrometry was used for analysis of oxidized fullerene derivative and material balance and elemental analysis were used to identify the summary composition of the prepared fullerene halogen derivatives. We has conformed yet the radioprotective ability of oxidized fullerene in our recently published work radioprotective properties and toxicity test of C60 fullerene derivative in vivo & in vitro. Since radioprotective properties are associated with the ability to recapture free radicals in the system (formed due to radiolysis of water in the physiological environment), this property is closely connected also with fire-retarder properties, when the fire is also a radical mechanism. We tested thermal properties of polyvinyl alcohol (hereinafter PVA) nanofibers prepared with C60 and its derivatives as nanocomposites. The TG-DTA and TG-DSC analysis were used for this purpose. We have demonstrated experimentally that a retarder on C60oxi basis and C60 halogenderivative has good results in increasing of thermal resistance of PVA-based nanofibers.

A Critical Review of Natural Gas Flares-Induced Secondary Air Pollutants

Application of material balance analysis (in one of our previous studies) to natural gas flare in the upstream petroleum operations confirmed the emission of primary air pollutants in form of CO, CO2, NO, and NO2 from “sweet” natural gas while “sour” gas emits SO2 in addition; incomplete combustion may be an impetus for the release of volatile organic compounds (VOCs) into the atmosphere from this same source. In this article, the significance of these gaseous emissions in the formation of secondary air pollutants in the atmosphere is reviewed for the purpose of air pollution control strategy. The goal is to describe the formation mechanism, to determine the influencing factors in formation along with environmental impacts and to identify the required technological and policy control approach for an improved environmental protection.

Development of Solar Ponds Optimization Model: Arab Potash Solar System—A Case Study

A steady state optimization model used to define the optimum salt to carnallite ponds area ratio in a solar pond system was developed. The model is based on material balance analysis using a cascade of complete-mix reactors model (cascade of CFSTR, continuous-flow stirred-tank reactor) prepared for the solar pond system. The basic material balance model shall use the basic phase chemistry relations and physical parameters of the solar pond system under optimization. The Arab Potash solar pond system data was used to examine the developed model where the Arab potash solar system was used as a Case Study. In the course of the model development, calibration and validation of the model is performed. Using this steady state model the optimum salt pond to carnallite pond area ratio is deduced. This optimum ratio is defined as the optimum area ratio that maximizes the carnallite production per the total pond system area. This term, which could be expressed as tons per km2, presents the best pond system efficiency. The results show that a 1.88 ratio of salt to carnallite ponds area is the optimum ratio.

Study Of Commonly Used Conventional Methods For Gas Reserve Estimation

DOI: http://dx.doi.org/10.3329/jce.v26i1.10185JCE 2011; 26(1): 54-61

Production of Porous Silica Microparticles by Membrane Emulsification

A method for the production of near-monodispersed spherical silica particles with controllable porosity based on the formation of uniform emulsion droplets using membrane emulsification is described. A hydrophobic metal membrane with a 15 μm pore size and 200 μm pore spacing was used to produce near-monodispersed droplets, with a mean size that could be controlled between 65 and 240 μm containing acidified sodium silicate solution (with 4 and 6 wt % SiO(2)) in kerosene. After drying and shrinking, the final silica particles had a mean size in the range between 30 and 70 μm. The coefficient of variation for both the droplets and the particles did not exceed 35%. The most uniform particles had a mean diameter of 40 μm and coefficient of variation of 17%. By altering the pH of the sodium silicate solution and aging the gel particles in water or acetone, the internal structure of the silica particles was successfully modified, and both micro- and mesoporous near-monodispersed spherical particles were produced with an average internal pore size between 1 and 6 nm and an average surface area between 360 and 750 m(2) g(-1). A material balance and particle size analysis provided identical values for the internal voidage of the particles, when compared to the voidage as determined by BET analysis.

Study on Simulation Model of Hydrothermal-Treatment of Degradable Organic Wastes

An overall material and energy balance analysis of hydrothermal-treatment system is conducted; a model for simulating the hydrothermal-treatment process is established. The experimental hydrothermal-treatment results of lawn-grass are used to test and prove the effectiveness of the model; and a series of technical parameters are obtained including time duration, reaction temperature, content of hemicellulose, cellulose and lignin etc.. The model can be used for technical design and operation control of lignocellulose biomass hydrothermal-treatment system.

Seasonal variations and chemical compositions of PM2.5 aerosol in the urban area of Fuzhou, China

The mass concentrations and chemical compositions (elements, water-soluble ions and carbonaceous species) of PM2.5 aerosol were detected in the urban area of Fuzhou city across four seasons from April 2007 to January 2008. The mass concentrations of PM2.5 ranged from 18.45 to 78.89μg/m3, with the average value of 44.33±16.30μg/m3. The elemental compositions were dominated by Si, Ca, Fe, K, and Al. SO42−, NO3−, and NH4+ were the major ions, contributing 24.3%, 9.9%, and 8.8% to the total PM2.5 mass. The concentrations of above ions showed distinct seasonality of 2.2, 8.0, and 5.9 times higher in winter than those in summer, respectively. (NH4)2SO4 and NH4NO3 were the main forms in summer and winter and NH4NO3 mainly existed in autumn, while (NH4)2SO4, NH4HSO4 and NH4NO3 existed in spring. The high NO3−/SO42− ratio suggested that vehicular exhaust made an important contribution to atmospheric pollution. TC occupied 24.1% of PM2.5 mass, with a distribution of 19.2% OC and 4.9% EC. OC and EC had the common dominant sources in spring due to their strong correlation. The OC/EC ratio showed obviously seasonal distribution of 5.0 in spring, 2.7 in summer, 3.6 in autumn, and 4.2 in winter. The material balance analysis indicated that the fractions of major chemical species in PM2.5 were in the following order: OM>sulfate>soil dust>nitrate>ammonium>EC>chloride.

Estimating in-place volume and reservoir connectivity with real-time and periodic surveillance data

This paper demonstrates the value of collecting and interpreting real-time data. With an intensive data gathering strategy, starting at wells' inception to the mature production phase, we show how transient pressure and rate data can be used to manage a complex carbonate gas reservoir. In particular, reservoir connectivity is discerned with pulse testing and with the leading-edge p/ q graph, and continuous updates of in-place volume are made with both static and dynamic material-balance methods and corroborating the same with rate-transient analysis. Interwell connectivity information was deduced during underbalanced drilling by way of interference test between two pairs of wells. Thereafter, transient-pressure tests on individual wells characterized the layered, dual-porosity system, with production logs corroborating the notion of layering. Production maturity over three years has paved the way for estimating connected in-place gas volume associated with each well using the transient-PI, and also with a new method introduced here. This new approach entails plotting both static and dynamic material-balance data on the same graph, yielding the same solution. Errors associated with real-time rate measurements presented interpretation challenges for rate-transient analysis; however, application of a physics-based filtering algorithm resolved this issue. Flow-after-flow tests that were embedded in monthly variable-rate production allocations, in turn, allowed us to obtain average-reservoir pressure explicitly to do the static material-balance analysis.

An independent water system with maximized wastewater reuse for non-potable purposes - Model case for future urban development

A study was conducted to formulate an optimized plan for upgrading an independent water system in a college campus where the available water source is from 5 groundwater wells with a maximum water supply capacity of 3000 m3/d but the water demand is much beyond this value for both potable and non-potable consumption. By water balance analysis, it was estimated that with the available fresh water consumed only for potable and related miscellaneous uses for 30000 people, the quantity of the reclaimed water could be enough to cover all the non-potable consumption. By material balance analysis, the pollutant loadings of organics, nitrogen and phosphorus were calculated and the requirements for pollutant removal corresponding with reuse purposes were evaluated. Considering the quality criteria of water reuse for lake landscaping, toilet flushing and gardening, and the demand for each water usage in the campus, a dual-quality reclaimed water supply scheme was proposed as (1) supply of lower quality reclaimed water for gardening and road sprinkling by upgrading the existing wastewater treatment facility of 1500 m3/d using conventional process, and (2) supply of higher quality reclaimed water for lake water replenishment and toilet flushing by implementing a new wastewater treatment facility of 2500 m3/d using MBR process. The independent water system thus optimized could sustain a total water consumption of more than 6000 m3/d using the 3000 m3/d source water. This provided a model case for future urban development in the water deficient region.

Understanding well performance with surveillance data

This study presents an inception-to-maturity data acquisition philosophy and deriving value from such surveillance. Specifically, translating wellhead pressures (WHP) to bottomhole pressures (BHP) allowed many reservoir-engineering calculations during the flow period. While conversion of WHP to BHP proved feasible during a flow test, measurements showed that shut-in tests do not lend themselves for such treatment because of rapid heat dissipation of a low-heat-capacity fluid, such as gas. Therefore, we relied upon flow-after-flow (FAF) tests that were embedded in monthly variable-rate production measurements to obtain average reservoir pressure and absolute open-flow potential. These average pressures enriched those that were obtained with downhole gauges from shut-in tests for the material-balance analysis. The resultant time-dependent inflow–performance relationship (IPR) and absolute-open-flow potential helped understand well performance. Indeed, evolution of declining IPR slope led to the identification of gradual wellbore blockage in one of the wells completed openhole. Downhole video recording confirmed mechanical issues in two openhole completions. Production logging showed preferential flow from the upper section of the thick carbonate interval in two wells. However, residual doubts remained about possible flow up the annulus in the openhole/slotted liner completions. Analytic modeling confirmed that the notion of preferential flow up the annulus is untenable.

Arsenite Oxidation by Immobilized Cells of Alcaligenes faecalis Strain O1201 in a Fluidized‐Bed Reactor

Arsenic(III) oxidation was evaluated in a continuous-flow fluidized-bed reactor (FBR) with Alcaligenes faecalis strain 01201 immobilized in gel beads. The FBR was operated under 300 mg/L citrate and a range of influent As(III) concentrations (75 to 3000 mg/L) at short hydraulic retention times (1.06 to 3.17 hours). The pH and temperature in the FBR were maintained at optimal growth conditions for strain O1201 (pH 7 and 30 degrees C) throughout the study. A total of 10 quasi-steady-state operating conditions were obtained after 54 days of operation under an As(III) concentration of 441 mg/L (10 000 mg/L/d loading rate), with As (III) removal efficiency ranging from 76% to near complete. Material balance analysis over the FBR revealed that the difference between the cumulative influent As (III) and the sum of cumulative effluent As(III) and As(V) was insignificant. The major mechanism of As(III) removal from the FBR is biological oxidation to As(V).

An Analytical Bottomwaterdrive Aquifer Model for Material-Balance Analysis

Summary In this study, we present a new analytical model to predict water influx from finite bottomwaterdrive aquifers (BWDAs). The new model can be used for aquifer representation in reservoir simulators and material-balance analysis. The new model is computationally fast. The model has been verified against the results from the Coats (1962) and Allard and Chen (1988) models. Using the new model, we compare the cumulative water influx from bottomwaterdrive (BWD) and edgewaterdrive (EWD) aquifers. In the second part, we couple the new aquifer model with the material-balance equation (MBE) and demonstrate its use in reserves estimate. Production data from a BWD oil reservoir simulated by Allard and Chen (1988) is analyzed. We conducted a McEwen analysis (1962) to predict the reserves.

Removal of VOCs from indoor environment by ozonation over different porous materials

Ozonation of toluene over NaX, NaY and MCM-41 adsorbents was studied targeting for indoor air purification. The combined use of ozone and the various micro- or meso-porous adsorbents aimed to take advantage of the strong oxidizing capability of ozone. At the same time the residual ozone would be minimized due to the enhanced catalytic reaction in the porous structure. To lower the residual ozone level is a crucial issue as ozone is itself an indoor pollutant. The Lewis acid sites in the adsorbents were believed to decompose ozone into atomic oxygen, and the subsequent reactions would then convert the adsorbed toluene into CO 2 and H 2O. In the dry conditions, the MCM-41 required the smallest amount of material to achieve the 90% reduction target, followed by NaY and NaX. In the more humid environment (50% RH), extra amounts of MCM-41 and NaX adsorbents were required to reach the target as compared with the dry conditions. Desorption experiments were also conducted to study the amounts of various major species held in the adsorbents during the catalytic process. A material balance analysis of the major species in both the effluents and the adsorbents showed that within our experimental conditions, about 20–40% of the removed toluene was carried out via catalytic ozonation while adsorption covered the rest. Trace amount of intermediate species such as aldehydes and organic acids were identified in the desorbed gas indicating that they were withheld by the adsorbents during the air purification process and those in the effluent were below detection levels.

A road map for improving the technical basis for the estimation of petroleum reserves

Reserves estimation can be based on one or more methodologies, each with its associated uncertainty. These include ‘static’ volumetrics, reservoir simulation, material-balance analysis, and/or projections of ultimate recovery according to production decline. The static volumetric method is in focus here, as the most commonly used approach during the development and early production stages when there has been limited petroleum recovery and the uncertainty associated with a reserves estimate can be considerable. There are several key technical aspects of the static volumetric process, including: the issue of minimum data requirements in relation to reservoir complexity; the upscaling of reservoir parameters and the interpretative algorithms through which they are interrelated; the identification of net reservoir and net pay; and the integration of data sources in a manner that is dynamically conditioned, i.e. tied back to permeation properties. This last point is especially important because reserves, by definition, are commercially recoverable. Suggested improvements reveal additional opportunities for cross-validation and groundtruthing. The approach is synthesized into a high-level, yet pragmatic workplan. It is proposed that the adoption of such a workplan will remove some of the uncertainty that is currently inherent in the technical process for estimating reserves.

Arsenite Oxidation by Alcaligenes Faecalis Strain O1201 in a Continuous-Flow Bioreactor

As(III) oxidation by a pure bacterial culture, Alcaligenes faecalis strain O1201, was evaluated using a continuous stirred tank reactor. The bioreactor system was operated for 204 days under a wide range of influent As(III) concentrations (500–8,000 mg∕L) and hydraulic retention times (25.6–90.7 h) with citrate as the sole carbon and energy source at pH 7 and 30°C. Nine steady-state conditions were obtained with As(III) oxidation efficiency exceeding 95%. The system quickly recovered from an As(III) overloading at 15,000 mg∕day∕L while it operated at a HRT of 12.8 h . A material balance analysis revealed that nearly all the As(III) removed in the continuous stirred tank reactor (CSTR) was oxidized to As(V) and only 3.2% of the As(III) fed to the CSTR was unaccounted for. Biokinetic parameters, kmc =0.86 mg∕mg cell dry weight/h and Kc =70 mg∕L , for As(III) oxidation were obtained using the Monod expression and data obtained at steady-state conditions.

An approach to measuring spatially resolved water crossover coefficient in a polymer electrolyte fuel cell

This paper reports on an experimental approach to measuring the water crossover coefficient distribution for the first time. A straight-channel PEFC of 6 cm 2 segmented into 10 pieces along the reactant flow direction has been developed. The instrumented cell, combining the functions of current collection and gas sampling with one pin for each segment, is capable of measuring current and species distributions simultaneously from a single experiment. The two distribution data are subsequently combined in a material balance analysis to yield the net water transport coefficient distribution through the membrane. For fully humidified anode and partially humidified cathode, the net water transport coefficient is found to range from 0.47 to 0.025, and the electro-osmotic drag dominates water transport through the membrane. For partially humidified anode and cathode, the net water transport coefficient lies between 0.19 and −0.24, with the negative value indicating dominant back diffusion.

AN OPTIMIZATION MODEL FOR TAILINGS DISTRIBUTION IN AN OILSAND INDUSTRY

An integrated model was introduced to manage tailings material distribution in an oilsand mining application. The resulting mathematical formulation of the model is a nonlinear optimization problem with an objective function, and sets of constraints covering tailings material balance, costs, and risk analysis. The model was developed using a nonlinear optimization software ‘LINGO’ which generates optimal solutions with very small gaps between actual data and tailings distribution plans.

Assessment of natural organic matter in Quabbin Reservoir

Quabbin Reservoir is a drinking water supply reservoir located in central Massachusetts. A study of natural organic matter (NOM) in Quabbin Reservoir was conducted using measures of total organic carbon (TOC), ultraviolet absorbance at 254 nm (UV-254), trihalomethane formation potential (THMFP), and apparent molecular weight distribution (AMWD) in Quabbin Reservoir and tributary waters. In general, NOM in Quabbin tributaries had elevated TOC, UV and THMFP, and different AMWDs as compared to Quabbin Reservoir. While distinct spatial (across the watershed) and temporal variations of NOM characteristics were observed in tributary inputs, the characteristics of reservoir NOM were relatively uniform with space and time. Measures of TOC, UV, THMFP and AMWD did not provide clear evidence of allochthonous and autochthonous NOM in the reservoir. One exception was the positive linear relationship observed between THMFP yield and blue-green algae density. Material balance analysis indicated that the net effect of waterbody processes on NOM inputs to the system was a reduction of 26% TOC, 71% UV-254 and 48% THMFP over a 2-year period, suggesting that waterbody processes differentially impact NOM characteristics.

Three dimensional reservoir geological model and multiple scenario volumetrics of the F23 Miocene carbonate buildup, Luconia Province, offshore Sarawak

Typically, the geology and production behavior of gas reservoirs in the atoll shaped Miocene carbonate structures of the Central Luconia province, offshore Sarawak, are best constrained in the center of the field due to a biased distribution of wells. Control over the reservoir architecture, pore volume and fluid flow behavior decrease significantly towards the reservoir flanks introducing uncertainties for an optimized reservoir management. An integrated reservoir geological study was initiated with the objective to decrease uncertainties and increase the understanding of their impact on static and dynamic reservoir models. Data from an integrated core, seismic and petrophysical evaluation, including lateral seismic porosity prediction and the application of geostatistics, were combined to a 3-D fully computerized reservoir model. The core and seismic evaluation reveals a complex internal reservoir architecture strongly influenced by paleo-wind pattern and sea-level fluctuations with backstepping, progradational and aggradational growth phases. Transgressive systems tracts are represented by dense argillaceous limestones, which form more or less continuous blankets possibly isolating gas volumes and influencing vertical water movement. During repeated periods of flooding the platform back-stepped up-wind only to prograde down-wind again during sea-level high stands until re-reaching the previous platform margin. An uncertainty tree was constructed for the F23 field in order to assess the impact of combined and individual uncertainties on static and dynamic reservoir models. Parameters considered in the uncertainty tree are the top carbonate structure, the porosity distribution, the hydrocarbon saturation and the gas expansion factor. Most likely, low and high cases were used in order to assess the parameters with the most impact on the uncertainty of hydrocarbon volume and fluid flow, in particular possible flank water encroachment. Results from the volumetric calculations arrive at a most likely GIIP close to that derived from material balance analysis. However, low and high cases significantly exceed the uncertainty range of the material balance GIIP. While the geology of the reservoir flank is now better constrained using refined seismic interpretations, uncertainties in these areas remain high.

Succession-of-States Model for Calculating Long-Time Performance of Depletion Reservoirs

Summary This study presents a new finite-element approach for directly calculating pseudosteady-state flow behavior for wells in depletion systems. The approach allows for spatially dependent reservoir properties, complex reservoir geometries, and multiple wells. Results are verified against long-time transient solutions reported in the literature for several regularly shaped systems. The paper also demonstrates application of the approach to field-scale problems. Results show that this approach provides a fast and accurate method for modeling the long-time behavior of depletion reservoirs. The approach is particularly applicable to single-phase volumetric gas reservoirs. A bounded reservoir with wells producing at constant rate will exhibit pseudo steady-state behavior after the end of typically short-lived infinite-acting and transition flow periods. This study develops a new approach for directly calculating pseudosteady-state flow behavior without solving the full time-dependent form of the diffusivity equation. This approach can be applied to the linearized forms of the diffusivity equation for either single-phase liquid or gas flow. A finite-element method is used that allows for spatially dependent reservoir properties, complex reservoir geometries, and multiple wells. The first part of this paper presents a verification of the approach by comparing results for some regularly shaped systems against full-transient solutions reported in the literature. For the simulation of field-scale problems with multiple wells of differing production rates, a well model based on a near-wellbore approximation of the pseudopressure distribution during pseudosteady-state is introduced to reduce the concentration of elements near wells. The second part of the paper demonstrates application of the direct pseudosteady-state concept to actual reservoir problems. To account for rate changes during extended production periods, the pseudosteady-state equation was solved successively for each flow period and combined with an overall reservoir material balance analysis. Results from this study show that this approach provides a fast and accurate method for modeling the long-time behavior of various types of reservoirs under depletion conditions. The approach is particularly applicable to single-phase volumetric gas reservoirs.