Study on Influencing Factors of Methane Production Efficiency of Microbial Electrolytic Cell with CO_(2) as Carbon Source

Reducing CO_(2) to produce methane through microbial electrolytic cell(MEC)is one of the important methods of CO_(2) resource utilization.In view of the problem of low methanogenesis rate and weak CO_(2) conversion rate in the reduction process,theflowfield environment of the cathode chamber is changed by changing the upper gas cir-culation rate and the lower liquid circulation rate of the cathode chamber to explore the impact on the reactor startup and operation and products.The results showed that under certain conditions,the CO_(2) consumption and methane production rate could be increased by changing the upper gas recirculation rate alone,but the increase effect was not obvious,but the by-product hydrogen production decreased significantly.Changing the lower liquid circulation rate alone can effectively promote the growth of biofilm,and change the properties of biofilm at the later stage of the experiment,with the peak current density increased by 16%;The methanogenic rate decreased from the peak value of 0.561 to 0.3 mmol/d,and the CO_(2) consumption did not change signifi-cantly,which indicated that CO_(2) was converted into other organic substances instead of methane.The data after coupling the upper gas circulation rate with the lower liquid circulation rate is similar to that of only changing the lower liquid circulation rate,but changing the upper gas circulation rate can alleviate the decline of methane pro-duction rate caused by the change of biofilm properties,which not only improves the current density,but also increases the methane production rate by 0.05 mmol/d in the stable period.This study can provide theoretical and technical support for the industrial application scenario offlowfield regulation intervention of microbial elec-trolytic cell methanogenesis.

Study on Production Regulation of Reservoir under Different Demand

Natural gas production is related to the demand for gas, which is low in summer and high in winter. While the gas storage is still being demonstrated and constructed, oil and gas fields should formulate and implement production control schemes suitable for gas reservoirs. The realization of natural gas production can not only meet the demand of gas consumption, but also ensure the scientific and efficient development of gas reservoirs, and meet the needs of dynamic analysis of gas reservoirs at different development stages and scientific research of gas reservoirs. In this paper, KAPPA Workstation 5.20 software is used to determine the inflow dynamic model of a single well. The nodal method is used to determine the reasonable production and peak shaving capacity in combination with the critical fluid carrying capacity of gas wells and the erosion rate of gas wells. The reasonable production allocation in each period, i.e. the production control scheme, is obtained. It solves the scientific and efficient development of natural gas in X gas field, which is still under the construction of gas storage, and provides guidance for gas reservoir development management and regulation.

An Alternative to Flare Gas Processing:A Feasibility Study of Natural Gas to Liquid Processes

The quantities of gas released into the environment during the extraction and processing of crude oil,by flaring,constitute a vast source of mineral wealth which can be used to produce other useful products.The processes studied in this paper,as alternatives to the above problem,are the ones used in Shell Pearl Qatar project and Oryx GTL project.Both projects produce liquid fuels,mainly naphtha and diesel,in addition to more special fuel such as kerosene.This paper is a feasibility study of a project that makes use of the flare gas from the State of Texas,U.S.A.,as a feedstock to a process similar to either Shell Pearl Qatar project,or Oryx GTL project.The objective of this study is to determine the price range for crude oil over which an investment to similar projects can be profitable.An MS Excel Model was developed in order to perform calculations having as a variable the crude oil price and taking into account all the process and project’s financial data.The results of this model showed that a project similar to Shell Pearl Qatar remains profitable in crude oil price above$57.76/barrel,while a project similar to Oryx GTL remains viable for crude oil price over$31.4/bbl.In the price range$55-$60/barrel,the payout of the corresponding to Shell Pearl Qatar project will be in about 15.2 years and 3.3 years for a project similar to Oryx GTL.Finally,using the financial principles of this study we can apply them to any process in order to determine under what conditions will remain viable.

Comparative Analysis and Validation Methodologies of GC and HPLC for Analysis of Cholesterol in Meat Products

This study validated different extraction methodologies and compared the quantification of cholesterol by gas chromatography (GC) and high performance liquid chromatography (HPLC) in mg per 100 g of Italian-type salami and traditional bologna. The GC method used was direct saponification of the samples without derivatizations and the HPLC method was used to extract of the lipid samples. The GC limits of detection and quantification obtained for cholesterol were, respectively, 0.001 and 0.003 mg.g–1. The HPLC values were 0.005 mg.g–1 and 0.016 mg.g–1. The GC recovery rate was 97.10 ± 0.13 and that of HPLC was 93.33 ± 0.22. Comparison of the cholesterol quantity found using the two chromatographic techniques shows that both are capable of quantifying cholesterol in the foods. With regard to costs, analysis time, the cost/benefit relationship was better with gas chromatography than that obtained with high performance liquid chromatography.

Mathematical model study on the damage of the liquid phase to productivity in the gas reservoir with a bottom water zone

The production process in the gas reservoir with an aquifer is complex.With gas production,aquifer water could possibly flow into the production well and accumulate within the well bore,which leads to a lower production rate and may even block the producer.However,few studies in the literature investigate the damage caused by the liquid phase in this kind of reservoir or predict gas productivity using the relationship between reservoir pressure and water gas ratio(WGR).For this reason,it is important to know the effects of the formation of liquid phase behavior on production when an aquifer is present under a gas reservoir.From the results of published literature reviews,we found that studies focused on the production of a gas reservoir with bottom water.Nevertheless,for gas well damage from the liquid phase behavior,we found that there was no statistical data or mathematical model of the relationship between reservoir pressure and the gas oil ratio(GOR),which affects production.In this research,based on the theory of fluid flow in porous media,a new mathematical model of water and gas production and a new equation on gas well productivity is developed.To verify the model and equation,gas production data collected from the field are applied.By analyzing the typical gas reservoir with bottom water and the collected data,influences from the liquid phase behavior are shown.In this way,mathematical relationships between reservoir pressure and the WGR and between the GOR and production decline were obtained.The new gas productivity model is derived from the gas and water pseudo pressure functions,which can be applied to analyze well damage caused by the liquid phase.In order to verify the mathematical model,production data were collected from a typical gas reservoir with an aquifer located in the Changxing gas reservoir.The results indicate that a semi-logarithmic linear relationship is obtained between the WGR and productivity decrease.When the WGR increases from 0.5 to 15m3/104m3,damage caused by liquid phase decreases to 59%.The tendency of gas productivity in the Changxing gas reservoir was obtained so that it decreases as reservoir pressure decreases and increases as the WGR decreases.The gradient of the gas productivity deduction increases as the WGR increases.By the end of the data analysis,two linear equations indicating the relationship between gas productivity and reservoir pressure and the relationship between gas productivity and the water gas ratio are obtained:QAOF?A1lnWGRB1 and QAOF?A2lnPB2,respectively.