Crude Oil Prices Effect on Enhanced Oil Recovery Projects

Enhanced or tertiary oil recovery methods (EOR) contribute significantly in increasing oil recovery factor up to 60%. Additional oil recovery values depend on the type of the applied EOR method (thermal methods that include steam injection, in situ combustion; chemical methods such as polymer, alkaline or surfactant injection and injection of hydrocarbon, carbon dioxide or other gaseous fluids). Implementation of complex EOR methods involves high capital and operational costs, longer period of investmentˋs payback period and more risk and uncertainty in comparison to the use of conventional primary and secondary recovery methods of oil reservoirs.
In general, oil prices have the largest impact on the EOR projects’ economic viability.
Crude oil price decline since June 2014 had large impact at the world energy market, as well as at the application of oil exploitation methods and their commercial viability. In this paper are presented considerations of oil price impact on the oil production by EOR methods.

Low Cost Cup Electronic Anemometer

In all studies involving wind speed, such as meteorology, wind turbines and agriculture, require accurate speed information for decision making. There are several types of anemometers, with medium and high costs, such as Cup, hot wire and Pitot tubes, and the hot wire is more sensitive and expensive than others.The device developed in this work is the Cup anemometer, to be easy to build. The great advantage of this device is the low cost, with an approximate value of US$ 50.00, using simple materials and easy to find in commercial stores. The Reed Switch sensor is also another advantage as it does not require a sophisticated programming, as well as the open platform Arduino. The use of aerodynamic drag coefficients and the presented calculations resulted in values very close to a commercial anemometer with a good coefficient of determination(R^2 ). The present sensor was developed as part of the project of a meteorological station to monitor the micro-climate of the city of Catanduva-SP, Brazil.

Analysis of Multiple Injection Impact on Fuel Supply Parameters

Fuel injection causes considerable oscillations of fuel pressure at the injector inlet. One of the reasons is hydraulic impact originating when closing the injector nozzle needle. Evidently, these oscillations influence the fuel supply process in case of multiple injections: the previous injections would influence on the following ones. The influence of the interval between the impulses of a double injection on the injection rate value of the second portion was investigated. The superposition of waves in case of multiple injection may result both in amplification and damping of oscillations process. It is shown that with multiple injection, the controllability of fuel supply deteriorates, therefore, either a special design study of the fuel system for multiple injection or the introduction of additional electronic correction of control pulses by the diesel control system is required. On the other hand, it is shown how multiple injection can produce a stepwise injection characteristic, which can serve as a means of reducing nitrogen oxides and noise. Applied research and experimental developments are carried out with financial support of the state represented by the Ministry of Education and Science of the Russian Federation under the Agreement № 14.580.21.0002 of 27.07.2015, the Unique Identifier PNIER: RFMEFI58015X0002

Calculation of Losses in the Distribution Grid Based on Big Data

This paper represents an approach for calculation of losses in a distribution power grid from data which are normally collected by the grid operator. The proposed approach utilizes the least squares optimization method in order to calculate the coefficients needed for estimation of losses. The amount of data used in calculations is very large due to the fact that electrical energy injected in distribution grid is measured every fifteen minutes. Therefore, this approach is classified as the big data analysis. The used data set is available in the Serbian distribution grid operator’s report for the year 2017. Obtained results are fairly accurate and can be used for losses classification as well as future losses estimation.

Wind Farm Multiobjective Optimization using Nested Extremum Seeking Controls

Wind farm optimization has been the focus of research in recent years. Most of the control algorithms available to maximize the energy capture or reduce structural loads are model based. A Model-based controller is designed for wind turbines in ideal condition of operation. In real world, the actual wind power is a function of factors such as wind shear, temperature and surface roughness of the blade. This reduces the effectiveness of a model-based controller. Extremum seeking controls is a real-time, model free optimization algorithm that can adapt to the changes in the design and environment. Previous studies have shown the effectiveness of the algorithm to only maximize the energy capture, without considering the increase of structural loads. This paper presents a novel multiobjective nested extremum seeking controls algorithm to maximize the energy production and minimize the structural loads. The results show 30% reduction of the damage equivalent loads of the main shaft, and 25% reduction of the tower while increasing ~1% power output of a wind farm compared to a baseline controller.

Application of Multi-criteria Decision-making Methods in Energy Research – a Review

Multi-criteria decision making (MCDM) has been widely employed in different research domains that typically involve complex decision-making problems. Energy planning is one of the most challenging contemporary development domain. Building on previous studies, the objective of this paper is to review some characteristics of recent application of MCDM in energy research. 132 articles from the Scopus database, for period 2017-2018 were analyzed in respect to ten criteria. Besides the rising trend in application of MCDM it is shown that 1) the most used method is AHP, 2) the traditional form dominates, 3) MCDM are primarily used in evaluation studies, focusing on combined energy sources or solar energy, 4) hybrid approaches are employed more than individual methods, 5) most of the MCDM methods are applied in its original form, 6) the most researched spatial level is national, 7) top-ranked journal is Energy, and 8) most articles come from China.

Contribution of Renewable Energy Sources to Overall National Energy Security Policy

Energy is necessary for the functioning of every society. Although the development implies increasing energy efficiency, due to the increase in the number of inhabitants, introduction of various new technologies and development of automated industry, there is significant increase in energy needs. The lack of energy is therefore a threat to the security of every country. The use of renewable energy sources increases country energy independence. In this paper, the importance of application of renewable energy sources in Serbia in the context of its energy security policy has been considered.

Potential of Climate Change Mitigation Associated with the Utilization of Solar Thermal Energy in the Ice Cream Industry

The negative environmental impact associated with the generation of thermal energy in the Brazilian industrial sector has become an increasing concern due to its contribution to global warming. The implementation of solar thermal energy, through flat collectors, has been studied to minimize negative environmental impacts. This can reduce atmospheric emissions associated with the installation and generation of thermal energy for use in industrial processes. The pasteurization process of ice cream was analysed herein, using the Life Cycle Assessment (LCA) methodology. SimaPro software v. was utilized, with the EcoInvent database. The environmental impact assessment method chosen was IPCC 2013 GWP 100y, which expresses the environmental impact in terms of kg CO2-eq (carbon footprint). An ice cream factory located in João Pessoa (Northeast Brazil) was selected to represent the case study: the existing system (LPG burner) was compared with a solar thermal energy system. The carbon footprint of the existing system was 2172 kg CO2-eq/year while the impact of the solar system (flat collectors) was only 117.9 kg CO2-eq/year, demonstrating a reduction of 2054 kg CO2- eq/year (-95%). These results highlight the introduction of solar thermal energy as an environmentally viable alternative.

Exergetic Pinch Evaluation of a Steam Power Plant Heat Exchanger Network

In this paper, a steam power plant’s heat exchanger network (HEN) is analyzed, using the pinch, exergy, and combined pinch and exergy methodologies, in order to evaluate its performance under design and operational conditions. The pinch analysis show that, under current operational conditions, the minimum hot utility requirement was 539,491kW at a temperature of 549°C, which is 30,618kW (6.02%) more than the design minimum hot utility requirement (508873.7kW), and the optimum minimum temperature difference between hot and cold streams ( ΔT min ) in the HEN is 12°C. Results from standard exergy analysis showed that heaters 5, 2 and deaerator performance improved while the other components experienced decrease in exergetic efficiencies. Though the boiler had the highest avoidable and inevitable exergy losses 〖(ĖL〗_AVO and 〖Ėx〗_INE) respectively, Heater 3 showed the most potential for performance improvement with (158.04%). Followed by Heater 6 (54.7%), the deaerator (15.15%), the condenser (13.55%), and Heater 1 (12.62%) when we consider 〖ĖL〗_AVO/〖Ėx〗_INE . A combined pinch and exergy analysis (CPEA) gave similar outcomes, and showed further that changes in cold stream properties majorly led to performance declines observed. For improved plant performance, the exergy losses identified in the HEN should be reduce beginning from the cold streams.

Improved Algorithm for FEM Analysis of MTL Problems

This paper deals with improvement of time integration scheme for transient finite element method (FEM) analysis. FEM is applied to the system of hyperbolic differential equations i.e. system of multi-conductor transmission line (MTL) equations. Spatial integration of system of hyperbolic differential equations is usually done by the weighted residual method. Improvement of accuracy was obtained by using Heun’s method. Numerical solutions obtained using Heun’s method and using the generalized trapezoidal rule for different values of a time integration parameter ϑ are compared to analytical solution. It has been shown that Heun’s method yields the results with much higher accuracy comparing to results obtained by generalized trapezoidal rule (ϑ-method) with the approximately equal computational time.