Gas Production Plants Research Articles

Distributed MPC for Upstream Oil & Gas Fields - a practical view

This work aims to improve corporate functional departments’ confidence in adopting modern control approaches in new scenarios and thus presents control structure solutions based on MPC for two control problems facing existing upstream oil & gas production plants; these are the disturbance growth in the series connected process and the control system dependency on operators. The proposed approach integrates distributed MPC (DMPC) as a master controller for the existing classical control of each subsystem, with a focus on those with high interaction phenomena. The proposed DMPC also considers safeguarding, constraints and the enhancement of plant-wide optimal performance. The suggested control solution reduces the role of control room operators which is shown to reduce the growth in the impact of process disturbances. Compared with some alternative control structures (centralised MPC, decentralised MPC, distributed MPC (DMPC), and hierarchical DMPC) this proposal is simple, inexpensive to implement, and critically, builds on the local team operational experience and maintenance skills.

Simulating and Optimizing Auto-Thermal Reforming of Methane to Synthesis Gas Using a Non-Dominated Sorting Genetic Algorithm II Method

Conventional synthesis gas production plants consist of a natural gas steam reforming to CO + 3H2 on Ni catalysts in a furnace. An alternative method for highly endothermic steam reforming is auto-thermal reforming. In this work, synthesis gas production by auto-thermal reforming was simulated based on a heterogeneous and one-dimensional model in two cases. The first case was the auto-thermal reformer of Dias and Assaf's study. The present work was validated by the reported experimental results. The second case was the fixed-bed catalytic auto-thermal reactor operated at high pressure, which was suitable for methanol production and Fischer–Tropsch reactions (baseline case). Then, the effect of operating variables on the system behavior was studied. Finally, Pareto-optimal solutions were determined by non-dominated sorting genetic algorithm II. The objectives included obtaining a H2/CO ratio of 2 in the produced synthesis gas and the maximum methane conversion. The adjustable parameters were the feed temperature, mass flux, and O2/CH4 and H2O/CH4 ratios in the feed.

Fatigue failure of thermowells in feed gas supply downstream pipeline at a natural gas production plant

A natural gas production field has been set into operation about six years ago. Natural gas produced from the well is processed through different stages before being supplied through pipelines for local market. Temperatures of the gas during its different processing and supplying stages are being monitored using thermowells made of type 316L austenitic stainless steel. In this concern, flanged, straight type thermowells were used for the feed gas supply downstream pipeline (30 in. diameter). This thermowell type consists of a straight tube and a flange. The tube outer diameter, thickness and length are 19 mm (0.75 in.), 6.5 mm (0.256 in.), 260 mm (10.24 in.) while the flange diameter and thickness are 155 mm (6.1 in.) and 23 mm (0.91 in.) respectively. The thermowells are fixed in a vertical position where its flanges are 200 mm above the top of the pipeline. Actual operating conditions are given. After only one year of operation, several thermowells have experienced failure.

GRA(Generic Risk Analysis) 기법을 이용한 공기분리시설에 대한 준 정량적 위험성 평가에 관한 연구

가스제조 시설들은 불활성 가스공급을 통하여 제조업 시설의 안전한 운영 및 유지하는 역할을 하며, 폭발성, 가연성 및 독성가스를 공급하여 화학제품 제조에 필요한 기초 원료의 공급을 담당하는 역할을 한다. 또한 가스의 제조과정에서 고온, 고압, 초저온 및 촉매반응 등의 운전조건 하에서 시설이 운전되기 때문에 안전하고 신뢰성 있는 운영이 반드시 필요하다. 이러한 공장들은 공정관리가 복잡하며 제조물질의 누출로 인한 화재, 폭발 및 독성가스 누출로 인한 중대산업사고의 위험성이 있고, 불활성가스로 인한 질식재해, 고온 및 초저온으로 인한 화상 등 잠재적인 위험요소를 많이 가지고 있다. 본 연구는 신뢰성 있는 준 정량적 위험성평가 기법인 GRA(Generic Risk Analysis) 모델을 공기분리시설(ASU)에 적용하여 초기위험도(Initial Risk) 산정, 안전방벽(Safety Barriers) 적용, 잔여위험도(Residual Risk) 산정 및 중요안전요소(EIS, Elements Important for Safety)를 도출 하였으며, 위험성 평가 결과로 도출된 중요안전요소에 대한 효과적인 안전관리 및 시행절차의 구축을 제안하였다. The gas production plants supply the inert gas to production plants for maintaining safe operation and also supply combustible, flammable, explosive and toxic gases as functions of basic materials needed for producing chemical goods. In addition, gas plants need to be safe and reliable operation because they are operated under high temperature, high pressure, cryogenic and catalytic reactions. As these plants have a complex process in operation, there has been a risk that major industrial accidents such as a fire, explosion and toxic gas released, also risks of asphyxiations by inert gases and burns caused by high temperature and cryogenic substances. This study is to carry out the semi quantitative risk assesment method which is the generic risk analysis (GRA). This method is applied to air separation unit(ASU) to identify its initial risk, safety barriers, residual risk and elements important for safety(EIS). The result of this study, suggested the management tools and procedures of implementation for EIS management.

合成ガス製造装置用耐メタルダスティング合金「NSSMCTM 696」の開発

合成ガス製造装置用耐メタルダスティング合金「NSSMC^TM 696」の開発

Shutdown preparedness in oil and gas production

PurposeThe purpose of this paper is to present an approach for measuring the ability of oil and gas production plants to utilize shutdowns opportunistically for maintenance.Design/methodology/approachKey performance indicators have been developed from case studies with two offshore oil and gas installations on the Norwegian Continental Shelf. The key performance indicators measure the quality of the work preparations and the ability to utilize shutdowns opportunistically. Shutdowns may provide opportunities for execution of maintenance, but it is hardly possible to undertake any maintenance work requiring shutdown if the organization is not well prepared and the work is not well planned.FindingsThe results from testing of the indicators on two oil and gas installations shows that several of the indicators are relevant for determining the quality of preparations, whereas more effort needs to be put into gathering data applicable for monitoring the actual utilization of the shutdowns.Research limitations/implicationsProduction losses, due to turnarounds and unforeseen shutdowns in oil and gas operations, are significant, and the improvement potential is large. The indicators may assist maintenance managers in planning and improving the plant's utilization of shutdowns and may contribute to substantial cost savings.Originality/valueThe approach in the paper adds important knowledge on how to actually measure the quality of maintenance work planning and execution.

Integrated engineering environment for the process FEED of offshore oil and gas production plants

In this paper, an offshore process front end engineering design (FEED) method is systematically introduced and reviewed to enable efficient offshore oil and gas production plant engineering. An integrated process engineering environment is also presented for the topside systems of a liquefied natural gas floating production, storage, and offloading (LNG FPSO) unit, based on the concepts and procedures for the process FEED of general offshore production plants. Various activities of the general process FEED scheme are first summarized, and then the offshore process FEED method, which is applicable to all types of offshore oil and gas production plants, is presented. The integrated process engineering environment is presented according to the aforementioned FEED method. Finally, the offshore process FEED method is applied to the topside systems of an LNG FPSO in order to verify the validity and applicability of the FEED method.

九十九里沿岸海域における天然ガス・ヨウ素工場周辺の窒素類の現況把握

九十九里沿岸海域における天然ガス・ヨウ素工場周辺の窒素類の現況把握

Mercury in hares organs (Lepus europaeus Pallas) in the vicinity of the mercury-contaminated natural gas treatment plant in Croatia

In the last two decades (1990–2008), as part of a comprehensive monitoring of the eco-system, hares were collected in the vicinity of the mercury contaminated natural gas production and treatment plant Molve, Croatia. Their organs (muscle, liver, kidney and brain) were analyzed for total mercury concentration by cold vapor AAS. The range of the median mercury concentration values (wet weight) in hares organs were 0.001–0.005, 0.007–0.045, 0.022–0.126 and 0.0006–0.015 μg/g for muscle, liver, kidney and brain, respectively. The results of mercury measurements in hares organs during the period of last twenty years demonstrate a small but constant decline in concentration values. Comparing the results obtained in this study with results published in available data and literature on mercury concentration in hare's tissue it can be concluded that area investigated in this research belongs to low mercury contaminated region. Nevertheless, further eco-monitoring and mercury measurements in various hares organs are valuable and necessary and will be continued.

Thermal analysis and optimization of an anaerobic treatment system of whey

The whey produced during cheese and cream cheese making process is one of the most important environmental problems dairy industries are facing, due to its high organic load. Anaerobic treatment seems to be a promising solution for this problem, since it not only reduces greatly the organic load but it also produces biogas, which can be then burnt. It is the scope of this study to perform an exergetic and economic analysis of an anaerobic treatment system of whey accompanied by the production of steam resulting from the burning of biogas. The system analyzed extends from the storage of whey, up to the disposal of the treated effluent from the anaerobic reactor, and the exit of the steam to be used in the plant. The exergy analysis is performed treating the system as a steam production plant, while the economic analysis, which is performed using the Net Present Value (NPV) method, is performed treating the system as a natural gas production plant. The exergy efficiency and NPV calculations are followed by a sensitivity analysis and an optimization with respect to some of the parameters used. Moreover, the exergy efficiency and NPV are calculated for three scenarios. The results indicate that the anaerobic treatment of high strength waste such as whey is a sustainable investment, at least for a substantial volume of whey.

Increased bioclogging and corrosion risk by sulfate addition during iodine recovery at a natural gas production plant

Iodine recovery at a natural gas production plant in Japan involved the addition of sulfuric acid for pH adjustment, resulting in an additional about 200 mg/L of sulfate in the waste brine after iodine recovery. Bioclogging occurred at the waste brine injection well, causing a decrease in well injectivity. To examine the factors that contribute to bioclogging, an on-site experiment was conducted by amending 10 L of brine with different conditions and then incubating the brine for 5 months under open air. The control case was exposed to open air but did not receive additional chemicals. When sulfate addition was coupled with low iodine, there was a drastic increase in the total amount of accumulated biomass (and subsequently the risk of bioclogging) that was nearly six times higher than the control. The bioclogging-associated corrosion rate of carbon steel was 84.5 μm/year, which is four times higher than that observed under other conditions. Analysis of the microbial communities by denaturing gradient gel electrophoresis revealed that the additional sulfate established a sulfur cycle and induced the growth of phototrophic bacteria, including cyanobacteria and purple bacteria. In the presence of sulfate and low iodine levels, cyanobacteria and purple bacteria bloomed, and the accumulation of abundant biomass may have created a more conducive environment for anaerobic sulfate-reducing bacteria. It is believed that the higher corrosion rate was caused by a differential aeration cell that was established by the heterogeneous distribution of the biomass that covered the surface of the test coupons.

Gibberellins producing endophytic Aspergillus fumigatus sp. LH02 influenced endogenous phytohormonal levels, isoflavonoids production and plant growth in salinity stress

Endophytic fungi are little known for exogenous gibberellins (GAs) production and plant growth promotion under salt stress conditions. We isolated 13 endophytic fungi from soybean roots, which were screened on Waito-C rice for plant growth promoting capacity. Endophytic strain, GMH-1a exhibited maximum growth during screening and thus was investigated for GAs production and host plant interaction. GMH-1a was identified as a new strain of Aspergillus fumigatus sp. LH02 through phylogenetic analysis of 18S rDNA sequence. Analysis of GMH-1a culture filtrate showed presence of GA4 (24.8ng/ml), GA9 (1.2ng/ml) and GA12 (9.8ng/ml). Soybean plants inoculated with GMH-1a significantly increased shoot length, shoot fresh and dry biomass, leaf area, chlorophyll contents and photosynthetic rate under salt stress (70 and 140mM) as compared to non-inoculated plants. GMH-1a inoculated plants had contained significantly lower endogenous abscisic acid (ABA) and elevated free proline, salicylic acid (SA) and jasmonic acid (JA) contents in comparison to their respective control treatments. Isoflavones, quantified through excessive HPLC analysis, showed that GMH-1a inoculated plants with/without salt stress contained higher isoflavones than non-inoculated plants and with/without NaCl stress. This novel endophytic fungus has reprogrammed soybean metabolism to improve plant growth and increase isoflavone contents under salt stress.

통합 프로세스 엔지니어링을 위한 해양 프로세스 기본 설계 방법론

In this study, an offshore process FEED(Front End Engineering Design) method is systematically established to perform integrated process engineering for topsides systems of LNG FPSO(Floating, Production, Storage, and Off-loading unit) based on the concepts and procedures for the process FEED of general offshore production plants. First, various activities of the general process FEED engineering are summarized, and then the offshore process FEED method, which is suitable for application to all t ypes of offshore oil and gas production plants, is proposed. Second, an integrated process engineering environment is built based on the proposed FEED method. Finally, the integrated process engineering environment is applied to topsides systems of an LNG FPSO in order to verify the validity and applicability of the proposed FEED method. As a result, it is shown that the proposed FEED method can be applied to the process FEED engineering of F PSOs and moreover will be able to contribute to perform successful offshore projects in the future.

Nitrogen Removal System Impacts on Secondary Treatment Greenhouse Gas Production and Whole Plant Carbon Footprint

Nitrogen Removal System Impacts on Secondary Treatment Greenhouse Gas Production and Whole Plant Carbon Footprint

Nitrogen Removal System Impacts on Secondary Treatment Greenhouse Gas Production and Whole Plant Carbon Footprint

Nitrogen Removal System Impacts on Secondary Treatment Greenhouse Gas Production and Whole Plant Carbon Footprint

Optimal Design of Synthesis Gas Production Process with Recycled Carbon Dioxide Utilization

Many countries are trying to reduce their primary energy demand and greenhouse gas (such as carbon dioxide (CO2)) emissions. There has been much research on CO2 utilization to reduce CO2 emission and increase economic efficiency in industries. In this paper, an integrated optimization strategy of an industrial synthesis gas production plant with additional CO2 recycling processes using carbon dioxide as a reactant is presented. The CO2 recycling process allows three different kinds of alternative synthesis gas reaction processes in parallel: steam reforming, dry methane reforming, and reverse water−gas shift reaction. The strategy is based on the integrated superstructure optimization that assists the formulation of the optimal process design problem such that mixed integer programming can be derived. The mathematical programming problem which has flexibility in selecting different synthesis gas reaction processes is used to find the optimal configuration of the process. The industrial synthesis gas plan...

Development of Mercury Adsorbent from Naphtha

Crude oil and natural gas condensate contain various metals including low levels of mercury. This mercury can cause various problems, such as catalyst degradation, piping corrosion and so on. For example, corrosion of piping in natural gas production plants, blockage of LPG vaporizers, and damage to aluminum components in heat exchangers have been reported. Silicates, alumina, activated carbon, and other materials are all effective adsorbents combined with metal sulfides for removing mercury from natural gas. However, these conventional adsorbents result in a further problem that the metal sulfide dissolves in the petroleum products, such as naphtha. The bonding energy was calculated by computer chemistry to identify new effective materials for mercury removal. Based on the bonding energy calculation, adsorbents with good predicted performance based on alkaline metal sulfide and metal chlorides were prepared using activated carbon with very large surface area as a support. Experiments identified a mercury removing adsorbent which has no effect on the properties of naphtha. Mercury removal equipment with the newly developed adsorbent has been operated in the Shikoku refinery of Taiyo Oil Co. since November 1995. This equipment is operated at normal temperature and pressure, and has processed over 5 million kl during 8 years. This is the one of the longest running mercury removal plants in the world.

Life cycle CO2 analysis of LNG and city gas

An analysis was conducted on greenhouse gas emissions from the liquified natural gas (LNG) chain and life cycle of City Gas 13A [caloric value: 46 MJ/Nm3(11,000 kcal/Nm3)], which is produced from LNG. The analysis was based on highly reliable data which are qualified in terms of source and representativeness. Actually, the latest data for CO2 and CH4 emissions from the natural gas field and liquefaction plant were obtained from field studies. Moreover, the analysis includes CO2 emissions during the LNG transportation from exporting countries to Japan, city gas production and distribution stage in Japan and the manufacturing of facilities associated with the production of natural gas overseas to final domestic consumption. The reduction effect of CO2 using LNG cryogenic energy was also considered. The evaluation showed that the level of greenhouse gas emissions and energy consumptions in the modern natural gas production and liquefaction plants were lower than those previously reported due to improvements in the production process. The results of the analysis also provide basic data essential for conducting life cycle analyses in many fields using natural gas.

Evaluation of oilfield corrosion inhibitors in CO 2 containing media: A kinetic study

Film-forming corrosion inhibitors are extensively used to control CO 2 corrosion of steel in oil and gas production plants. The performance of these inhibitors is connected to the persistence and/or regeneration of the protective film. Their active mechanism in the presence of CO 2 is still little understood as far as the kinetics is concerned. In this paper, some of the factors affecting this mechanism have been studied with the aid of polarization curves and electrochemical impedance, using rotating disc and cylinder electrodes. The performance of a commercially available film-forming inhibitor used in PET-ROBRAS, the Brazilian petroleum company, was evaluated. The results show that the efficiency of the inhibitor depends on its residual concentration and on the hydrodynamic flow conditions. The impedance diagrams provided information on growth, stability and deterioration of the inhibitor film.

Application of the urinary S-phenylmercapturic acid test as a biomarker for low levels of exposure to benzene in industry.

Recently, the determination of S-phenylmercapturic acid (S-PMA) in urine has been proposed as a suitable biomarker for the monitoring of low level exposures to benzene. In the study reported here, the test has been validated in 12 separate studies in chemical manufacturing plants, oil refineries, and natural gas production plants. Parameters studied were the urinary excretion characteristics of S-PMA, the specificity and the sensitivity of the assay, and the relations between exposures to airborne benzene and urinary S-PMA concentrations and between urinary phenol and S-PMA concentrations. The range of exposures to benzene was highest in workers in chemical manufacturing plants and in workers cleaning tanks or installations containing benzene as a component of natural gas condensate. Urinary S-PMA concentrations were measured up to 543 micrograms/g creatinine. Workers' exposures to benzene were lowest in oil refineries and S-PMA concentrations were comparable with those in smoking or nonsmoking control persons (most below the detection limit of 1 to 5 micrograms/g creatinine). In most workers S-PMA was excreted in a single phase and the highest S-PMA concentrations were at the end of an eight hour shift. The average half life of elimination was 9.0 (SD 4.5) hours (31 workers). Tentatively, in five workers a second phase of elimination was found with an average half life of 45 (SD 4) hours. A strong correlation was found between eight hour exposure to airborne benzene of 1 mg/m3 (0.3 ppm) and higher and urinary S-PMA concentrations in end of shift samples. It was calculated that an eight hour benzene exposure of 3.25 mg/m3 (1 ppm) corresponds to an average S-PMA concentration of 46 micrograms/g creatinine (95% confidence interval 41-50 micrograms/g creatinine). A strong correlation was also found between urinary phenol and S-PMA concentrations. At a urinary phenol concentration of 50 mg/g creatinine, corresponding to an eight hour benzene exposure of 32.5 mg/m3 (10 ppm), the average urinary S-PMA concentration was 383 micrograms/g creatinine. In conclusion, with the current sensitivity of the test, eight hour time weighted average benzene exposures of 1 mg/m3 (0.3 ppm) and higher can be measured.