Appraising Security of Upstream Gas Supply of Complex Network via Integrated Modeling & Simulation for Minimizing Value Leakage for Hydrocarbon Chain for Malaysian Asset

2021 ◽  
Author(s):  
Sukrut Shridhar Kulkarni ◽  
Imran Suhaimi ◽  
Gaurav Mishra

Abstract Gas supply security plays a vital role in ensuring the continuity of the power generation and distribution for one of Malaysian State. Unplanned deferments at offshore facilities creates enormous impacts on gas quantity leading to loss/lowering of power generation. Such occurrences lead to value leakage and hinders the expansion strategies by non-firming of investment decisions. It therefore becomes imperative as prudent operator to sustain upstream gas supply by ensuring the security by appropriate strategies in occurrence of such events. Also, for complex facilities it is decisive to have comprehensive understanding of network characteristic, offshore supplies distributions and topology in terms of hydraulics & flow regimes from multiple fields to ensure security of gas supply to customers. This paper proposes an approach to endorse the security of gas supply during normal and ad hoc situations by aligning the relevant feeders to respective demand centers thru comprehensible network modeling and ensure the optimized system response operating envelope for such events. An innovative process was commenced to design, develop, validate, and deploy the network simulation model to cater for the technical characteristics in terms of ullage, hydraulic first principles, blending aspects and safety features during aligning of the respective feeders. The landscape includes around 100+ feeders, multiple export pipelines, several gas highways, and many demand centers with each of its specific requirement. The inline equipment such as pressure boosters with performance curves (compressors/pumps), pressure manipulators (control valves) also formed the integral portion of the model for resilient outputs. Also, the equation of state (for thermodynamic behavior) and appropriate flow co-relation (for pressure drop estimations) were embedded in the model for representative results. The model was validated thoroughly with the plant data by identifying critical junction points to have realistic consequences. Input to the model were classified as engineering input (static such as design capacity, pressure limits, maximum allowable operating pressure (MAOP)) and operational inputs (flow allocations, priority of supply, precedence in operation of demand centers). The process was looped to reallocate the feeders till the required intent is met for the supply as well as on technical aspects. The simulation model could decipher the pain points across the various intensity of the networks such as pressure choking, unintended flow distribution, violations of the resultant specifications and potential breach in the safety limitations. Several iterations could be accomplished in terms of permutations and combinations to align appropriate feeders. The scenarios could be also optimized for the optimal value ranking of the fields to be evacuated for designated demand centers. The simulation model could suggest amendments in the operating strategy such as clustering of sweet/sour fields, integrated contaminant management system, and addition of loop lines to ensure the hydrocarbon molecule travels the intended path. Also, model assisted in generating the heat maps in terms of pressure concentration, flow dispersal and other aspects to have the big picture of the asset which can be probed as required. Network Modeling could recommend the relevant swing fields or alteration in the configuration in case of unforeseen circumstances if it occurs to ensure the security of supply of gas is intact to cater necessities. The approach could recommend that the upstream security of gas supply could be enhanced or endorsed via usage of Network Modeling by either by apposite changes in the operating philosophy and/or configuration. It also resulted into nurture trust of the stakeholder to empower the power generation using gas as fuel and business continuity is ensured for upstream.

Author(s):  
Illias Hischier ◽  
Pascal Leumann ◽  
Aldo Steinfeld

A high-temperature pressurized air-based receiver for power generation via solar-driven gas turbines is experimentally and theoretically examined. It consists of an annular reticulate porous ceramic (RPC) foam concentric with an inner cylindrical cavity-receiver exposed to concentrated solar radiation. Absorbed heat is transferred by combined conduction, radiation, and convection to the pressurized air flowing across the RPC. The governing steady-state mass, momentum and energy conservation equations are formulated and solved numerically by coupled Finite Volume and Monte Carlo techniques. Validation is accomplished with experimental results using a 1 kW solar receiver prototype subjected to average solar radiative fluxes in the range 1870–4360 kW m−2. Experimentation was carried out with air and helium as working fluids, heated from ambient temperature up to 1335 K at an absolute operating pressure of 5 bars.


Author(s):  
Xijia Lu ◽  
Scott Martin ◽  
Mike McGroddy ◽  
Mike Swanson ◽  
Josh Stanislowski ◽  
...  

The Allam Cycle is a high-performance oxy-fuel, supercritical CO2 power cycle that offers significant benefits over traditional fossil and hydrocarbon fuel-based power generation systems. A major benefit arises in the elimination of costly precombustion acid gas removal (AGR) for sulfur- (SOx) and nitrogen-based (NOx) impurities by utilizing a novel downstream cleanup process that utilizes NOx first as a gas phase catalyst to effect SOx oxidation, followed by NOx removal. The basic reactions required for this process, which have been well demonstrated in several facilities for the cleanup of exhaust gasses, ultimately convert SOx and NOx species to sulfuric, nitric, and nitrous acids for removal from the supercritical CO2 stream. The process results in simplified and significantly lower cost removal of these species and utilizes conditions inherent to the Allam Cycle that are ideally suited to facilitate this process. 8 Rivers Capital and the Energy & Environmental Research Center (EERC), supported by the state of North Dakota, the U.S. Department of Energy and an Industrial consortium from the State of North Dakota, are currently working together to test and optimize this novel impurity removal process for pressurized, semi-closed supercritical CO2 cycles, such as the Allam Cycle. Both reaction kinetic modeling and on-site testing have been completed. Initial results show that both SOx and NOx can be substantially removed from CO2-rich exhaust gas containing excess oxygen under 20 bar operating pressure utilizing a simple packed spray column. Sensitivity of the removal rate to the concentration of oxygen and NOx was investigated. Follow-on work will focus on system optimization to improve removal efficiency and removal control, to minimize metallurgy and corrosion risks from handling concentrated acids, and to reduce overall capital cost and operating cost of the system.


2018 ◽  
Vol 8 (2) ◽  
pp. 217-231 ◽  
Author(s):  
Wasana Bandara ◽  
Scott Bailey ◽  
Paul Mathiesen ◽  
Jo McCarthy ◽  
Chris Jones

Business process management (BPM) in the public sector is proliferating globally, but has its contextual challenges. Ad hoc process improvement initiatives across governmental departments are not uncommon. However, as for all organisations, BPM efforts that are coordinated across the organisation will reap better outcomes than those conducted in isolation. BPM education plays a vital role in supporting such organisation-wide BPM efforts. This teaching case is focused on the sustainable development and progression of enterprise business process management (E-BPM) capabilities at the Federal Department of Human Services: a large Australian federal government agency. The detailed case narrative vividly describes the case organisation, their prior and present BPM practices and how they have attempted BPM at an enterprise level, capturing pros and cons of the journey. A series of student activities pertaining to E-BPM practices is provided with model answers (covering key aspects of BPM governance, strategic alignment, culture, people, IT, methods, etc.). This case provides invaluable insights into E-BPM efforts in general and BPM within the public sector. It can be useful to BPM educators as a rich training resource and to BPM practitioners seeking guidance for their E-BPM efforts.


Energies ◽  
2018 ◽  
Vol 11 (4) ◽  
pp. 1016 ◽  
Author(s):  
Mauro Venturini ◽  
Stefano Alvisi ◽  
Silvio Simani ◽  
Lucrezia Manservigi

This paper deals with the comparison of different methods which can be used for the prediction of the performance curves of pumps as turbines (PATs). The considered approaches are four, i.e., one physics-based simulation model (“white box” model), two “gray box” models, which integrate theory on turbomachines with specific data correlations, and one “black box” model. More in detail, the modeling approaches are: (1) a physics-based simulation model developed by the same authors, which includes the equations for estimating head, power, and efficiency and uses loss coefficients and specific parameters; (2) a model developed by Derakhshan and Nourbakhsh, which first predicts the best efficiency point of a PAT and then reconstructs their complete characteristic curves by means of two ad hoc equations; (3) the prediction model developed by Singh and Nestmann, which predicts the complete turbine characteristics based on pump shape and size; (4) an Evolutionary Polynomial Regression model, which represents a data-driven hybrid scheme which can be used for identifying the explicit mathematical relationship between PAT and pump curves. All approaches are applied to literature data, relying on both pump and PAT performance curves of head, power, and efficiency over the entire range of operation. The experimental data were provided by Derakhshan and Nourbakhsh for four different turbomachines, working in both pump and PAT mode with specific speed values in the range 1.53–5.82. This paper provides a quantitative assessment of the predictions made by means of the considered approaches and also analyzes consistency from a physical point of view. Advantages and drawbacks of each method are also analyzed and discussed.


2021 ◽  
Author(s):  
Farshid Zabihian

The first part of this thesis deals with greenhouse gas (GHG) emissions from fossil fuel-fired power stations. The GHG emission estimation from fossil fuel power generation industry signifies that emissions from this industry can be significantly reduced by fuel switching and adaption of advanced power generation technologies. In the second part of the thesis, steady-state models of some of the advanced fossil fuel power generation technologies are presented. The impacts of various parameters on the solid oxide fuel cell (SOFC) overpotentials and outputs are investigated. The detail analyses of operation of the hybrid SOFC-gas turbine (GT) cycle when fuelled with methane and syngas demonstrate that the efficiencies of the cycles with and without anode exhaust recirculation are close, but the specific power of the former is much higher. The parametric analysis of the performance of the hybrid SOFC-GT cycle indicates that increasing the system operating pressure and SOFC operating temperature and fuel utilization factor improves cycle efficiency, but the effects of the increasing SOFC current density and turbine inlet temperature are not favourable. The analysis of the operation of the system when fuelled with a wide range of fuel types demonstrates that the hybrid SOFC-GT cycle efficiency can be between 59% and 75%, depending on the inlet fuel type. Then, the system performance is investigated when methane as a reference fuel is replaced with various species that can be found in the fuel, i.e., H₂, CO₂, CO, and N₂. The results point out that influence of various species can be significant and different for each case. The experimental and numerical analyses of a biodiesel fuelled micro gas turbine indicate that fuel switching from petrodiesel to biodiesel can influence operational parameters of the system. The modeling results of gas turbine-based power plants signify that relatively simple models can predict plant performance with acceptable accuracy. The unique feature of these models is that they are developed based on similar assumptions and run at similar conditions; therefore, their results can be compared. This work demonstrates that, although utilization of fossil fuels for power generation is inevitable, at least in the short- and mid-term future, it is possible and practical to carry out such utilization more efficiently and in an environmentally friendlier manner.


2020 ◽  
Vol 219 ◽  
pp. 02001
Author(s):  
Nikolay Ilkevich ◽  
Tatyana Dzyubina ◽  
Zhanna Kalinina

This paper proposes taking into account new properties of gas supply systems in a mathematical model of flow distribution in comparison with the traditional formulation. The approach suggests introducing an arc coefficient, which allows for changes in the magnitude of gas flow passing along the arc, a vector of an increase in the arc throughput, and lower constraints on the gas flow along the arc. We also propose considering a new economic environment, namely, new criteria for optimizing the flow distribution and setting fictitious gas prices for consumers. These criteria enable us to take account of the priority gas supply to a definite group of consumers. As an example, the calculation of gas flows for the aggregated Unified Gas Supply System (UGSS) for 2030 is considered. This calculation takes into account the arc coefficients and the increase in the throughput of arcs.


Diversity ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 420
Author(s):  
Chee Hoe Chuan ◽  
Balu Alagar Venmathi Maran ◽  
Tzuen Kiat Yap ◽  
Kai Ching Cheong ◽  
Muhammad Ali Syed Hussein ◽  
...  

Jellyfish play a vital role in the ocean’s ecosystem, acting as a nursery for young fishes, crabs, and brittle stars, as well as a source of food for certain charismatic megafauna, such as sunfish and sea turtles. They also pose a threat to human activities, with jellyfish blooms negatively impacting fisheries, power generation, and tourism. However, very little information is available on the biodiversity of jellyfish within the waters of Borneo. Here, we present new records of jellyfish found along the coast of Sabah, Malaysia, located in northern Borneo, bordering the megadiverse region of the Coral Triangle. A total of six species belonging to two classes and six families hitherto not recorded to the state are reported, Chironex yamaguchii, Acromitus maculosus, Crambione mastigophora, Linuche aquila, Netrostoma sp., and Phyllorhiza punctata. Of these, two species (C. yamaguchii and L. aquila) are harmful to humans, with C. yamaguchii capable of causing human fatalities. Reports of harmful jellyfish are useful to the medical and tourism industry, as some of these species may inflict stings and adverse reactions to humans ranging from rashes and skin irritation to fatal envenomation. A checklist has also been provided for all collected jellyfish species from Sabah waters of Borneo, Malaysia.


2020 ◽  
Vol 4 (01) ◽  
pp. 56-65
Author(s):  
Hayati Mukti Asih

Yogyakarta has increasing trends in the number of vehicles and consequently intensifying the traffic volume and will effect to higher emission and air pollution. Traffic lights duration plays a vital role in congestion mitigation in the critical intersections of urban areas. This study has objective to minimize the number of vehicles waiting in line by developing the hybrid simulation method. First of all, the MKJI and Webster method were calculated to determine the green traffic light. Then, the simulation model was developed to evaluate the number of vehicles waiting in line according to different duration of green traffic lights from MKJI and Webster method. A case study will then be provided in Pelemgurih intersection located in Yogyakarta, Indonesia for demonstrating the applicability of the developed method. The result shows that the duration of green traffic lights calculated by Webster method provides lower number of vehicles waiting in line. It is due to the short duration of green traffic light resulted by Webster method so that the traffic light cycle becomes shorter and it effects the number of vehicles waiting in line which is lower than MKJI method. The results obtained can help the generating desired decision alternatives that will important for Department of Transportation, Indonesia to enhance the road traffic management with low number of vehicles waiting in line.


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