Natural Gas Refineries Research Articles

Recent advances in metabolic engineering of Corynebacterium glutamicum as a potential platform microorganism for biorefinery

AbstractThe fermentative production of platform chemicals in biorefineries is a sustainable alternative to current petroleum‐refining processes. Industrial microorganisms, such as Escherichia coli, Saccharomyces cerevisiae, and Corynebacterium glutamicum, have been engineered as microbial cell factories that are able to utilize biomass for the production of value‐added platform chemicals and polymers. Compared to E. coli and S. cerevisiae, C. glutamicum displays weak carbon catabolite repression and can co‐utilize mixed sugars as carbon sources, without any significant growth retardation. Pathways for the utilization of alternative carbon sources, such as d‐xylose and l‐arabinose from lignocellulosic biomass, lactose and galactose from whey, glycerol from biodiesel, and methanol from natural gas refineries, have been evaluated for chemical production. However, the application of C. glutamicum in biorefineries is limited because it does not secrete hydrolases for the efficient utilization of cellulose, xylan, and starch from lignocellulosic and starch biomass. To solve the limitation, C. glutamicum has been engineered for the consolidated bioprocessing of biomass by the heterologous expression of amylolytic and cellulolytic enzymes. Recently, C. glutamicum has been extensively engineered for polyamide monomer production owing to its ability to produce l‐lysine and l‐glutamate. This review summarizes recent advances in the development of C. glutamicum strains that can utilize renewable biomass resources for the production of industrially important chemicals. It highlights recent progress in metabolic engineering for the production of polyamide monomers. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd

Improving energy efficiency in a complex natural gas refinery using combined pinch and advanced exergy analyses

A real-life case study of a Heat Exchanger Network (HEN) in a complex natural gas refinery was considered, using the pinch technology concept combined with advanced exergy analysis (so-called CPEA). This could be done by supertargeting, a tradeoff between capital and operational costs, applied to the five divided zones in the plant, based on the concept of zonal targeting method. It was shown that the potential of improvement on both the utility consumption and the heat recovery were about 36.09% and 42.65% respectively, so there was a huge potential of the energy saving relative to the existing network. Meanwhile, a new approach to the advanced exergy analysis of HENs has been proposed by considering ΔTmin = 0 °C in the well-developed Carnot factor-Enthalpy diagram of balanced exergy composite curves. Considering unavoidable exergy loss in the retrofitted network, it was shown that the CPEA method led to the exergetic efficiency of 88.27%, which shows more than 78% improvement compared with 49.45% of the existing network. So from practical points, the CPEA method represents a new attempt to develop a systematic framework to optimize complex HENs in energy systems, by using an integrated set of pinch and advanced exergy analyses, in order to reduce the energy consumption most efficiently, while strongly promoting cleaner production alternatives.

A simple method for estimating the irreversibly in heat exchanger networks

This article presented a simplified method for quick estimating exergy destruction and irreversibility distribution ratio (φ) in a complex Heat Exchanger Network (HEN) of a large natural gas refinery in South Pars Gas Field located in the Persian Gulf. By the presented method, the designing of the HEN isn't required and the only necessary data are the temperatures and thermo-physical properties of the fluids at the inlets and outlets of the HEN. The equation of exergy destruction for the HEN was developed and the model was adapted to estimate the contributions of heat transfer and pressure drops due to fluid friction, as the two major causes of irreversibility in the HEN. The irreversibility factors were compared with the results obtained by conventional irreversibility analysis, i.e. considering irreversibility analysis of all individual heat exchangers running in the HEN. By comparison of the results of the two methods, it was shown that the values and trends of the irreversibility factors estimated by the two methods were approximately the same. By this procedure, it is possible to estimate the irreversibility distribution ratio in any HEN very quickly, especially in early stages of the thermal system designs, without solving very complex mathematical relations.

A practical approach to heat exchanger network design in a complex natural gas refinery

In this paper, a real-life case study of a complex natural gas refinery has been analyzed using the pinch technology concept, so that heat recovery as well as total hot and cold utilities have been improved for the main process units. This can be done by total heat transfer area and cost targeting, which called supertargeting. Two basic approaches to this analysis were developed, one for all hot and cold process streams simultaneously, without any restrictions and constraints, which was called “overall pinch method”, and the other for five divided areas in the plant, each consisting of some processing units, called “zonal targeting method”. Then the results were compared with each other and the potential of improvements was determined for each case. The result of this study showed that the retrofitted HEN using zonal targeting method improved total energy consumption and heat recoveries dramatically. Also, some modifications have been proposed, using grid diagrams to retrofit the existing HEN, in order to comply with energy recoveries determined from pinch analysis. Off course, this can be done by considering more investment (capital cost) for installation of new heat exchangers, in such a way that the operating costs can be remarkably reduced.

A STUDY ON THE ESTABLISHMENT AND IMPLEMENTATION OF CONSERVATION PROGRAM IN ARUN LNG PLANT

Energy conservation is an important issue in all sectoral activities, especially in processing industries such as natural gas refinery and liquefaction plant, petrochemical and cement mill in which energy isused in large amount. This paper presents a discussion on the experience in establishment and implementation the energy conservation program, including the reduction of greenhouse gas (GHG) emission achieved in the last four years in Arun LNG Plant, a commercial natural gas liquefaction plant in Aceh, Indonesia with a capacity of 2.2 million ton LNG per year. In addition, an analysis on the specific energy consumption and CO2 reduction is provided. The Energy Management Matrix was adopted in assessment of the energy management implementation in theArun LNG Plant. It was found that the efficiency of the plant tended to decrease from year to year, which was represented by the specificity of fuel consumption (accounted based on the LNG product). In 2010 the specific fuel consumption was 0.0088 mmscf per m3 LNG product; it was up to 0.0234 in 2013. Fortunately, it was observed that the specific CO2 reduction (calculated on the LNG product basis) increased during tlast four years; in 2010 and 2013 the specific CO2 reduction was 0.195 and 0.518 ton per 105 m3 LNG produced, respectively.

Prediction of carbon dioxide solubility in ionic liquids using MLP and radial basis function (RBF) neural networks

Elimination of carbon dioxide from gas mixtures is a common commercial step in natural gas refineries. Nowadays, room-temperature ionic liquids, which are a relatively novel type of compounds have gained attention in recent years and have potential to be considered as a substitution for conventional volatile organic solvents in reaction and separation processes. No flammability, high thermal stability, a wide liquid range, and electric conductivity are some properties of ILs, which make them interesting more and more.Information about the solubility and the rate of solubility is a crucial factor for consideration of ILs for potential industrial processes. Because of some difficulties associated with experimental measurements and expenses spent on ILs, developing predictive methods for prognostication of the phase behavior of such types of systems are more favorable. Thermodynamic models are relatively complex and require complicated mathematical operations.Due to such difficulties there is a need to develop general models capable to predict phase behavior of systems such as CO2 with various kinds of ILs. In this study, four different methods based on artificial intelligence are proposed to predict CO2 solubility in different ionic liquids. The results showed that the predicted values are in great agreement with the experimental data and the maximum absolute error deviation for the best predictor is no more than 3.5%. A comparison between developed models and previously published ones reveals the superiority of the proposed models in this study.

Natural Gas Refinery Wastewater Treatment by Zeolites

The purpose of this study is to experimentally investigate the SAR (Sodium Adsorption Ratio) and TDS (Total Dissolved Solids) reduction in reverse osmosis (RO) concentrate, using two types of natural zeolites. In order to reduce salinity of wastewater, experiments are carried out by varying the type of zeolite, concentration of zeolite, and residence time. The results show that both zeolites can lower the SAR and TDS of wastewater; however, Rhyolitic tuff is more effective than clinoptilolite. It is observed that the concentration of zeolite has not significant effects on wastewater treatment so, using the lowest level of selected concentration reduces the cost of desalination. In addition, the effect of residence time is negligible. The experimental set up shows that the SAR reduction slop is higher than TDS.

Experimental and theoretical study on BTEX removal from aqueous solution of diethanolamine using activated carbon adsorption

Activated carbon beds are extensively used in sweetening units of natural gas refineries for the purification of contaminated amine solutions. Correlation of experimental adsorption data using an analytical isotherm equation is need to design an accurate activated carbon bed. In the present study, the adsorption of BTEX from Diethanolamine (DEA) solution by commercial and granular activated carbon (AC) were performed. The Langmuir, Freundlich and Sips isotherm models were used to describe the equilibrium data. The accuracy of the results obtained from the adsorption isotherm models was compared and the values for the regressed parameters were reported. The results show that the Freundlich and Sips isotherms have better agreement with the experimental data than Langmuir isotherm for all AC samples. According to the adsorption isotherm curves obtained from experiments, the amount of adsorption of metaxylene, ethylbenzene, toluene, benzene increases respectively. In addition, a mathematical model was proposed for describing the BTEX transfer between the amine solution and solid particles. The breakthrough predicted by the proposed model was compared with the experimental results and a satisfactory agreement was observed between them.

Debottlenecking of condensate stabilization unit in a gas refinery

The increase in throughput or reduction in the operational costs is the common example of change in production criteria in retrofit projects. In this study, the condensate stabilization unit of a gas refinery, which is one of the most energy consuming units in natural gas refineries, is considered for analysis and retrofitting study. This unit comprises of a two-stage compressor and a side-reboiler associated with the stabilization column that uses HP steam as hot utility. It is shown that by applying the optimum pressure drops method for debottlenecking of this unit, after 20% increase in throughput, utility consumption can be maintained at existing level, if 1554 m2 of additional heat transfer area is installed.

Support Vector Machine based modeling of an industrial natural gas sweetening plant

In this study Support Vector Machine (SVM) is employed to develop a model to estimate process output variables of an industrial natural gas sweetening plant. The developed model is evaluated by process operating data of Hashemi Nejad natural gas refinery in Khorasan/Iran. A set of 13 input/output plant data each consisting of 145 data has been used to train, optimize, and test the model. Model development that consists of training, optimization and test was performed using randomly selected 80%, 10%, and 10% of available data respectively. Model estimations are compared with those obtained from an ANN based model developed using the same dataset as used for training and test of SVM based model. Test results from the SVM based model showed to be in better agreement with operating plant data compared to artificial neural networks based model. The minimum calculated squared correlation coefficient for estimated process variables is 0.99. Based on the results of this case study SVM proved that it can be a reliable accurate estimation method.

Hepatoprotective effect of silyamarin in individuals chronically exposed to hydrogen sulfide; modulating influence of TNF-α cytokine genetic polymorphism

Background and the purpose of the studySilymarin, a standardized extract of the milk thistle (Silybum marianum), is believed to exert some of its hepatoprotective effects though inhibition of free radicals and inflammation. In this study the effect of some pro- and anti-inflammatory cytokines and also antioxidant genes polymorphisms on the hepatoprotective effects of silymarin in the occupationally exposed individuals to hydrogen sulfide (H2S) in the sour natural gas refinery was investigated.MethodsWe genotyped seven polymorphisms in six genes reported by others as modifiers of oxidative stress (NQO1, mEPXH1, GSTT1 and GSTM1) and inflammation (TNF-α and TGF-β1) for an association in effect of decreasing in liver function tests (LFTs). The LFTs of 77 sour gas refinery workers were measured before and after administration of silymarin (140 mg, three times per day for 1 month).ResultsA significant reduction of blood AST, ALT and ALP was observed after 30 days of consumption (p < 0.001). The decreasing effect of silymarin on ALT in the subjects with high producer genotype (A allele carriers) was less than low producers. There were no significant associations between TGF-β1 and the studied genes of oxidative stress pathway and the effectiveness of silymarin.ConclusionThis is the first report about the effectiveness of silymarin in the subjects exposed chronically to H2S. Meanwhile, the modulatory effect of TNF-α on the effectiveness of silymarin might be used for individualize therapy.

A novel process configuration for co-production of NGL and LNG with low energy requirement

In this study a novel integrated process configuration for NGL/LNG production is introduced and analyzed. This configuration uses two mixed refrigerant cycles in order to supply the required refrigeration for production of both NGL and LNG. The results showed that not only liquefaction efficiency of the process is considerable (0.414kWh/kg LNG) but also it can recover the ethane (from a rich typical feed gas (methane 75%, and heavier hydrocarbons 23%)) higher than 93.3%. Four multi stream heat exchangers were utilized, the composite curves of them shows that they have been designed optimally. These heat exchangers perform their role for both targets simultaneously due to the integration of the NGL and LNG processes. Even though this point increases their size, but the total capital costs of the plant decrease. This process can be used for large LNG plants in the natural gas refineries. It can also be said that the overall efficiency will be higher for the leaner feed gases.

Studying the impact of mental health on job performance of managers and staff

The purpose of present research is to study the relationship between job performance and employees’ mental health in one of Iranian natural gas refinery located in city of Jam, Iran. Data collection was conducted based on two major characteristics of job performance and mental health based on questionnaire methods among 42 people. The methodology is descriptive and correlation – type and to analyze the data, Pearson’s correlation coefficient, variances equality tests as well as t-student were utilized. The findings show that there was a significant relationship between employees’ job performance and mental health and any increase in mental health aspects promotes job performance proportionally. In the meantime, there was no significant relationship between employees’ job performance and their gender and there was no significant difference on mental health status between male and female staff. Based on the results, one can conclude that low mental health level among employees can reduce their performance. Managers should use proper methods to decrease the negative consequences resulted from the lack of mental health in workplaces.

Oxidative stress induced in the workers of natural gas refineries, no role for GSTM1 and GSTT1 polymorphisms

Oxidative stress has an important role in the pathophysiology of many occupational diseases. In this controlled exposure study, the intensity of oxidative stress biomarkers was assessed in the workers of natural sweet and sour gas refineries (SwGR and SoGR, respectively) and compared with controls. In addition, the role of gluthatione S-transferase M1 (GSTM1)-null and GSTT1-null polymorphisms on the intensity of oxidative stress and liver function tests (LFTs) was investigated. Blood samples were taken and measured for lipid peroxidation (LPO) level, total antioxidant capacity (TAC) and total thiol molecules (TTMs). GSTM1- and GSTT1-null genotypes were determined using polymerase chain reaction. LPO was significantly (p < 0.05) higher in the workers of SoGR. TAC was significantly lower in SwGR subjects (p < 0.001). TTMs were significantly lower in SoGR and SwGR subjects. Among LFTs, activities of aspartate aminotransferase and alanine aminotransferase but not alkaline phosphatase were elevated significantly (p < 0.001) in SoGR subjects. Multivariate linear regression revealed no association between studied polymorphisms, oxidative stress biomarkers, and LFTs. These results indicate that working in the SoGR and SwGR can lead to oxidative stress and abnormal LFTs. Continuous monitoring of natural gas workers for probable ongoing problems is therefore suggested.

Enhanced aminophenols monitoring using in-channel amperometric detection with dual-channel microchip capillary electrophoresis

Improved techniques are needed to monitor toxic aminophenols in industrial wastewater. Microchip capillary electrophoresis (CE)-electrochemical detection (ECD) can be used to develop miniaturized system providing on-site monitoring. Here, a dual-channel microchip CE-ECD has been applied for the monitoring of aminophenols. The effect of conductance and capacitance between a working electrode and a reference electrode has been studied to minimize the noise that was generated in the amperometric detection. A mixture of aminophenols dissolved in a running buffer has been monitored. A separation efficiency with a plate number of 4770 and a high linear concentration dependence from 100 nM to 1 mM have been achieved for p-aminophenol. As a result, the analysis system has been applied for the monitoring of the pollutants with low detection limits of p-aminophenol (14.6 nM), o-aminophenol (10.6 nM) and m-aminophenol (15.3 nM). Here, we show that a wastewater sample from a natural gas refinery can be monitored using the microchip CE-ECD system.

Flare Gas Recovery in Oil and Gas Refineries

Environmental and economic considerations have increased the use of gas recovery systems. Regarding our comprehensive process evaluation in 11 oil and gas refineries, we devised practical methods to approach zero flaring. This paper presents the results of two case studies of reducing, recovering and reusing flare gases from the Tabriz Petroleum Refinery and Shahid Hashemi-Nejad (Khangiran) Natural Gas Refinery, both in Iran. The design considerations, economics of the process and system operation are studied in this paper. Flare gases are compressed and returned to the fuel gas header for immediate use as fuel gas. Flare gas recovery reduces noise and thermal radiation, operating and maintenance costs, air pollution and emission, and fuel gas and steam consumption. Process stability and flare tip increment without any impact on the existing safety relief system are also the effects of the flare gas recovery system.

非鉄金属製錬の現状と課題

Present status and issues of non-ferrous extractive metallurgy were described in this short review from resource and environmental points of view. Recent trend of shortage of non-ferrous ores and severe regulations gave several impacts to non-ferrous extractive metallurgical industry, although significant innovations of non-ferrous extractive metallurgical processes have not been done in this decade.There are three big issues in the society. The first one is how to control iron, sulfur and minor impurities like arsenic. Sulfur is over supplied in the world, then more than 10 millions tons sulfur are stored near oil and natural gas refineries. Therefore, a development of new application of sulfur is still essential. Usage of slag is also big problem. Since regulations on the usage of slag became severe, we have to change a mind that slag is not a sink of minor impurities but an important by-product containing iron which is major impurity in non-ferrous ores.Good collaboration of each non-ferrous smelter and refinery will be required to keep them in Japan to treat not major non-ferrous metals but harmful minor elements like arsenic and cadmium. Keeping non-ferrous industry is one of keys to achieve the sustainable development in Japan.

Iraq's other power struggle [electricity shortage causes

Since the war ended in 2003, Iraq has continued to struggle with its power situation with electricity production remaining pegged at about 4,000 MW primarily. Determined terrorists continue to disrupt electricity supply by attacking oil and natural gas refineries and even plants or pipelines. To address this problem, officials are looking for ways to attain sustained recovery. The Iraqi government plans to invest $20 billion over the next five years to increase production to 18,000 MW. It is also studying ways to harness alternative power sources such as hydro and solar resources.

Respiratory health of a population living downwind from natural gas refineries.

Since 1958 there has been a perception of excess illness in a rural Canadian population living downwind from two natural gas refineries, the emissions of which contain mostly sulfur dioxide but also hydrogen sulfide. To determine if there was an excess of adverse health outcomes in the population exposed (defined by place of residence), a health survey was undertaken in 1985 in this area and in one unexposed to emissions but demographically similar. Participation was 92% from both the exposed population (n = 2,157) and a representative sample (n = 839) of the main reference population. More respiratory symptoms were reported in the exposed group than in the non-exposed group among those 5 to 13 yrs of age (28% versus 18%) and among never-smokers greater than or equal to 14 yrs of age (35% versus 24%). FEV1, FVC, and FEV1/FVC were similar in both areas. Dichotomizing the level of exposure (high, low) within the exposed area revealed a trend in the high exposure area toward increased respiratory symptoms in the younger age group (39% versus 24%), but decreased symptoms in the older age group (33% versus 36% among never-smokers). FEV1 was similar between the two areas. The excess of respiratory symptoms in the exposed area unassociated with impaired spirometric values would be compatible with increased awareness of health or a small biologic environmental effect.

Cancer downwind from sour gas refineries: the perception and the reality of an epidemic.

A rural population in southwestern Alberta, Canada, living downwind from natural gas refineries, has expressed concerns about an excess of adverse health outcomes over the last 25 years. This has escalated to the point of causing a prominent sociopolitical controversy within the province. As part of a large field epidemiologic study undertaken during the summer of 1985 to investigate possible health effects, a residential cohort study was carried out to study cancer incidence. The cohort was defined as all those individuals who resided in the area in 1970. A total of 30,175 person-years of risk within Alberta were experienced by this cohort from 1970 to 1984. The incident cancers during this period were enumerated by computerized record linkage with the Alberta Cancer Registry. Age- and sex-standardized incidence ratios, based on expected rates from three prespecified demographically similar, nonmetropolitan Southern Alberta populations, were 1.05, 1.09, and 1.03, respectively, none of which was significantly different from unity. Although they do not address the issue of etiologic association, these data can provide considerable reassurance to a community that was convinced it had experienced an epidemic of cancer.