Steam Energy Research Articles

個人・地域・世界を結ぶSTEAM（科学・技術・工学・農学・数学）型エネルギー教育モデルの開発（２）

個人・地域・世界を結ぶSTEAM（科学・技術・工学・農学・数学）型エネルギー教育モデルの開発（２）

PERHITUNGAN POTENSI CADANGAN PANASBUMI LAPANGAN “X” MENGGUNAKAN DATA EKSPLORASI

The method used in this reserve estimation is volumetric, regulated by Badan Standar Nasional Indonesia (BSNI) (SNI 13-6482-2000). This method considers that the reservoir is a form of dimensional space so that its volume can be measured. This type of method can also be used in reserve classes ranging from hypothetical resources up to proven reserves, with parameters used in this calculation obtained through assumptions and those that are the result of preliminary survey activities, which consist of geological (MT maps), geophysics (MT maps), and geochemistry (geothermometer) surveys. Data obtained from preliminary survey activities contains data on thickness, area, and temperature of the reservoir. Other parameters that have not been obtained from preliminary survey activities, such as rock porosity and heat capacity, final temperature, water and steam saturation, internal energy of water and steam, water and steam density, recovery factor, load factor and span and are based on assumptions compiled by BSNI (SNI 13-6482-2000). In addition of using volumetric methods, calculations are also performed using the Monte Carlo simulation method. This method uses random numbers as uncertainty factors in some parameters that have been obtained from the preliminary survey as mentioned above, with the type of distribution determined based on calculation parameters.. With the reservoir temperature of 220oC, area of 7.4 km2, & thickness reaches 1550 m, the potential for geothermal reserve at "X" Field based on the volumetric method is 36.90 MWe. Meanwhile, using the Monte Carlo simulation method, the potential reserves at a 90% confidence level are around 47.93 MWe: which has the the most likely reservoir temperature of 220oC with the range of values varies around 200-225oC, reservoir area with the most likely value is 7.5 km2 ranging from 4-11 km2, and the most likely thickness value is 1550 m with 1200-1700 m for the minimum and maximum values.The calculation results of the geothermal energy reserve potential in the "X" Field are 36.90 MWe using volumetric method and 47.93 for Monte Carlo simulation method.

Boundary Dam or Petra Nova – Which is a better model for CCS energy supply?

SaskPower’s Boundary Dam plant (Canada) and NRG’s Petra Nova plant (USA) are the only two commercial-scale coal-fired power plants currently operational in the world that use carbon capture and storage (CCS) technology. While both CCS installations are retrofit projects that employ a post-combustion CO2 capture system using advanced amines, the two plants differ significantly in their approach to providing the steam and electrical energy requirements of the capture system. This paper presents a comparative techno-economic evaluation of pulverized coal (PC) power plants equipped with the different CCS system configurations used in these two demonstration plants, as well as two additional design configurations that may be of interest. The results presented in this paper illustrate the conditions which favor one approach over the other, and thus provide insights for planning new large-scale CCS projects.

Специальные турбогенераторные установки

Special-purpose turbine—generator units (TGUs) with a capacity of up to 10 000 kWfor converting the mechanical energy of steam into electricity with improved vibroacoustic characteristics are studied. The TGU includes a steam turbine, a synchronous generator excited from permanent magnets, and a frequency converter regulating the parameters of the electric power output. The turbine and generator rotation frequency is such that the TGU output frequency varies from 50 to 300 Hz depending on the TGU power. Different basic circuits of self-contained units equipped with generators excited from permanent magnets are considered. The design of a turbine—generator unit equipped with parallel-connected frequency converter is proposed, the use of which makes it possible to achieve essentially better mass and dimension characteristics of the converter and enhance the TGU reliability as a whole.

Energy-saving mechanism and parametric analysis of the high back-pressure heating process in a 300 MW coal-fired combined heat and power unit

Comprehensive and parametric analyses were conducted to investigate the thermal characteristic of the high back-pressure (HBP) heating process based on a 300 MW coal-fired combined heat and power (CHP) unit. The results indicated that the HBP design promoted the thermal efficiency of the unit by 5.97% (absolute value) and cut down the standard coal consumption rate by 23.52 g/(kW·h), attributing to the exhaust steam recovery efficiency of 57% and the unit generation power increase of 24.58 MW. On the grounds of the first and second laws of thermodynamics, the detailed energy-saving mechanism of the HBP heating concept was synthetically explored by the analyses of energy and exergy flows and graphical exergy, and the results showed that the HBP heating configuration improved the unit performance by reducing the exhaust steam energy loss and the extraction steam flow rate and raising the exergy efficiency of the heat exchange process. The impacts of the primary parameters (unit generation load, unit heating load, supply & return-water temperatures and turbine back-pressure) on the performance of the HBP-CHP unit were also examined and optimization suggestions were put forward. Besides, the heat and power coupling characteristic of the HBP-CHP unit was discussed.

An energy-friendly alternative in the large-scale production of soybean oil

Soybean oil is widely used as cooking oil, whereas the soybean cake is a valuable ingredient for animal food. The extraction of soybean oil is an energy-intensive process, with additional significant impact on the environment via the wastewater and hexane emissions. The research investigated different ways to minimize the energy consumption. In a traditional process, both direct (live) steam and indirect steam heating (jackets, tubular exchangers) are used to deliver the required heat duty. Direct steam injection is restricted to the first evaporator and the stripper, for a total of 620 kg/h. Indirect steam is also applied in the evaporators for a total of 6.44 MW. The desolventizing process requires a steam energy input of 8.15 MW. Integration of a heat exchanger network in the evaporation and stripping part of the process reduces the amount of direct steam usage from 620 kg/h to 270 kg/h and of the indirect heat duty from 6.44 to 5.05 MW. In the cake desolventizing part of the process, the energy requirement is reduced from 8.15 to 2.12 MW. The overall gross energy saving is hence ∼50%. The improvements moreover reduce both the waste water loadings by 56.5% and the CO2 emissions by 62.5%. Hexane emissions are moreover significantly (>90%) reduced.

Impact of amine@ZnO/CNT and fatty acid@ZnO/CNT as hydrophilic functionalized nanocomposites on reduction of heavy oil viscosity

One of the important features of heavy oil reservoirs is their high viscosity, which reduces the recovery factor of oil in these reservoirs. Thermal methods have traditionally been used for viscosity reduction in enhanced recovery process (EOR). However, these methods are not justifiable due to the high cost of steam energy production, the production of coke in the process, steam injection and environmental problems. Viscosity can be dramatically reduced with the help of nanoparticles, without using limited and controlled heat. In this study, ZnO/CNT nanocomposites, which have been made hydrophilic by surface modification operations, have been used as aqueous based nanofluids in enhanced recovery process. A heavy oil with viscosity of 402 cP at 80 °C was used in viscosity reduction tests. The results showed that the viscosity reduction of heavy oil from 402 cP at 80 °C to 74.90 and 16.23 cP at 80 °C is possible using reference nanofluids based on ZnO and CNT nanoparticles, respectively. In the next step, the effect of four parameters of concentration, salinity, pH and mixing intensity on the heavy oil viscosity were investigated to evaluate the performance of the nanocomposite. Amine surface modified nanocomposite samples fluidized in distilled water and fatty acid surface modified nanocomposites fluidized in seawater functioned better and reduced the viscosity to 33.74 and 26.08 cP at 80 °C, respectively. The effect of pH on viscosity was negligible, which is a positive feature of these nanocomposites. The mixing process of oil and nanofluid on viscosity reduction was shown to have much more effect on viscosity reduction in comparison to non-mixing process. The greatest reduction of viscosity without mixing was measured to be 261.26 cP at 80 °C using fatty acid@ZnO/CNT nanofluid, which is almost ten times more than the condition that mixing was performed ideally.

An area-wide layout design method considering piecewise steam piping and energy loss

Pipeline layout is a significant factor influencing an area-wide layout. But in the most of published works, piping system only consists of the one-to-one connection pipelines with constant diameters. In addition, energy loss is sometime ignored in previous works. In this work, energy loss due to pressure loss and heat loss is taken into consideration originally. An improved method is proposed to design an industrial area-wide layout considering the optimization of pipe network. The pipe length of steam piping is optimized based on Kruskal algorithm. The diameters of steam piping are piecewise considered. The flow rates are obtained by solving a linear programming (LP) model. The problem of area-wide layout optimization is solved by genetic algorithm (GA). Finally, the results of a case study show that the optimization of piecewise steam piping can reduce the total flow rate and energy loss of all branches in the pipe network.

個人・地域・世界を結ぶSTEAM（科学・技術・工学・農学・数学）型エネルギー教育モデルの開発（１）:―私たちの日常生活とエネルギーを中心とした実践―

個人・地域・世界を結ぶSTEAM（科学・技術・工学・農学・数学）型エネルギー教育モデルの開発（１）:―私たちの日常生活とエネルギーを中心とした実践―

Change in Steam Generators Main and Auxiliary Energy Flow Streams During the Load Increase of LNG Carrier Steam Propulsion System

In this paper is presented an analysis of main and auxiliary steam energy flow streams from steam generators during the increase in steam system load at conventional LNG carrier. During the steam system load increase was presented differences in steam pressure and temperature between main and auxiliary steam flow streams. Energy power of the auxiliary flow stream is higher than energy power of the main flow stream only at the lowest steam system loads after which main flow stream takes over primacy at middle and high steam system loads. Cumulative auxiliary energy flow stream was divided on energy flow streams to each auxiliary device and energy power consumption of each auxiliary device was also investigated throughout number steam system loads. Analysis of steam production from marine steam generators presented in this paper provides insight into the operation dynamics of the entire steam propulsion system.

An Improved Heating System with Waste Pressure Utilization in a Combined Heat and Power Unit

An improved heating system integrated with waste pressure utilization (WPU) for combined heat and power (CHP) cogeneration was proposed. The new heating system efficiently utilized the excess pressure of the extraction heating steam to drive the WPU turbine and generator for producing electricity, achieving higher energy efficiency and lower fuel consumption of the CHP unit. The results of the detailed thermodynamic analysis showed that applying the proposed concept in a typical 300 MW coal-fired CHP unit could reduce the standard coal consumption rate by 9.84 g/(kW·h), with a thermal efficiency improvement of 1.97% (absolute value). Compared to that of the original heating process, the energy efficiency of the proposed process decreased by 0.55% (absolute value), but its exergy efficiency increased dramatically by 17.97% (absolute value), which meant that the proposed configuration could make better use of the steam energy and contribute to the better performance of the CHP unit. As the unit generation load and supply and return-water temperatures declined and the unit heating load rose, the WPU system would generate more electricity and its energy-saving benefit would be enhanced. This work provides a promising approach to further advance the CHP technology and district heating systems.

Development of Nuclear Reactors Technology and General Feature of Egypt Nuclear Power Plants

AbstractNuclear reactors technology has been dramatically developed since the era of the first Fermi Pile fission reactor during the 2nd world war.Generation I and II reactors had been used for peaceful electricity generation and military (e.g. nuclear submarines) purposes.As a matter of fact, Generation III and III+ were proposed, developed, deployed and currently in operation worldwide. Recently, floating units and SMR are available options. The Ge III++ is currently proposed.The generation IV options; such as MSR, are intensively discussed through GIF. None of them has been commercially constructed.Fusion experimental reactor is on the track and road of reactors technology development. It needs some time for full plasma confinement to be safely controllable.Egypt has declared in 19 November 2015 and signed IGA for construction of 4 VVER Russian design reactors (pressurized water reactor) of 1200 MWe each (4.8 GWe total) at El-Dabaa site. In 11 December 2017, notices to proceed the contracts was signed in the presence of the president Abdel Fattah El Sisi. The Rosatom company will supplying Egypt with the nuclear fuel throughout the plant`s entire operational lifetime. The first unit is scheduled to be commercially commissioned by 2026. These reactors belong to Ge III+ that has post Fukushima features; advanced passive and active safety systems.According to the ministry of planning; by 2030, these reactors will contribute in the electricity portfolio of Egypt by about 10.5%. While, coal and renewable (solar and wind) sources will contribute by 15% and 21% percentage in 2020 respectively.Egypt, based on these plans, is going to has strategic energy mix consists of fossil; steam, combined, hydro and renewable energy sources.

Effects of Oxy-Fuel Combustion on Performance of Heat Recovery Steam Generators

The performance of steam power plants, utilizing recovered waste heat from air-fuel and oxy-fuel combustion, are compared. Temperature profiles in the heat recovery steam generator (HRSG), steam production rate, net-work output and energy efficiency are simulated for different conditions. Investigations are made into the effect of varying pinch point on HRSG performance, net-work and energy efficiency for power generation utilizing oxy-fuel combustion. It is found that with increased pinch point there is an associated decrease in HRSG and steam plant efficiencies. Exhaust gas composition influences the energy efficiency of the power plant. When air-fuel and oxy-fuel combustion are compared there is a reduced amount of nitrogen in the oxidant stream in the latter case. When comparing air-fuel and oxy-fuel combustion, a considerable deviation in HRSG and steam power plant performance is exhibited, with oxy-fuel combustion offering benefits in system efficiency and plant output. The exhaust gas composition at the HRSG inlet contributes significantly the performance characteristics of the system. Raising the HRSG inlet temperature also increases power generation and system efficiency. The results provide insights into the use of oxy-fuel combustion for systems utilizing HRSG for power generation while demonstrating the influence of gas composition, pinch point, and exhaust gas temperature on system performance, and suggest that oxy-fuel combustion can help enhance the contribution to sustainable development of some energy systems.

Energy and exergy analyses of circulatory flash evaporation of aqueous NaCl solution

In present study, an experimental system for circulatory flash evaporation was designed and built. Energy and exergy analyses of circulatory flash process were carried out. Basing on the first law of thermodynamics, the gained output ratio of circulatory flash evaporation (GORCFE) was defined as an energy ratio between latent heat carried away by flash steam and input excess energy of working fluids. The performance ratio of circulatory flash evaporation (PRCFE) was defined as the mass flow rate divided by exergy destruction rate. The Effects of main factors, namely, superheat degree, circulating flow rates, equilibrium pressure, initial water level and salinity on GORCFE and PRCFE were studied. Results suggested that GORCFE decreased rapidly at the initial stage, then increased with the increase of superheat degree and became flat eventually. The optimal superheat degree was determined wherein the maximum performance ratio was reached. According to the comparison of gained output ratio and performance ratio, the maximum performance ratio was obtained when gained output ratio was great enough and temperature difference was minimal.

Exergy efficiency analysis of lignite-fired steam generator

The operation of steam generators and thermal power plants is commonly evaluated on a basis of energy analysis. However, the real useful energy loss cannot be completely justified only by the First law of thermodynamics, since it does not differentiate between the quality and amount of energy. The present work aims to give a contribution towards identification of the sources and magnitude of thermodynamic inefficiencies in utility steam generators. The work deals with a parallel analysis of the energy and exergy balances of a coal-fired steam generator that belongs to a 315 MWe power generation unit. The steam generator is de-signed for operation on low grade coal - lignite with net calorific value 6280 to 9211 kJ/kg, in a cycle at 545?C/177.4 bar, with feed water temperature 251?C, combustion air preheated to 272?C and outlet flue gas temperature 160?C. Since the largest exergy dissipation in the thermal power plant cycle occurs in the steam generator, energy, and exergy balances of the furnace and heat exchanging surfaces are established in order to identify the main sources of inefficiency. On a basis of the analysis, optimization of the combustion and heat transfer processes can be achieved through a set of measures, including retrofitting option of lignite pre-drying with flue gas and air preheating with dryer exhaust gases.

Behaviour of Condensation for High Steam Energy and Water in Vertical Annular Channel

In this paper, condensation for high steam energy in vertical annular channel was investigated. Simulations were carried out to investigate the behaviour of condensation using FLUENT 14.5 in static water and steam velocity 0.2ms-1. The results show that, the steam outer surface show rapid condensation activity effect from the steam velocity. Due to this effect, further investigate may require to show condensation behaviour with the various steam velocity.

A novel multi-period mixed-integer linear optimization model for optimal distribution of byproduct gases, steam and power in an iron and steel plant

Byproduct gases, steam and electricity play an important role in providing energy for production units in the iron and steel industry. Optimal distribution of byproduct gases, steam and electricity in an iron and steel plant can significantly decrease energy cost and reduce CO2 emissions. However, such optimal distribution is not trivial because it involves many production units, steam turbines, combined heat and power units, and waste heat and energy recovery units, and several realistic operational features such as byproduct gas mixing, byproduct gas level control in dedicated gasholders, different levels of steam requirement, minimum heating and energy requirement, and maximum allowable burner switches, resulting in a large complex combinatorial problem. In this paper, we develop a novel multi-period mixed-integer linear programming model for optimal distribution of byproduct gases, steam, and power in an iron and steel plant. The consuming rates of byproduct gases are variable. Different byproduct gases are allowed to be mixed to satisfy minimum heating and energy requirement of production units. The steam is specifically classified as high, medium and low pressure. New binary variables are introduced to determine electricity purchase or sale decision with each having different price. The burner switching operation is correctly modeled with fewer binary variables allowing turning on and off at any time. Several important practical features such as fuel selection, gasholder level control, ramp rate variation, piecewise constant generation rates of byproduct gases, and piecewise constant demand profiles of byproduct gases, steam and electricity are also incorporated. The computational results demonstrate that the optimal operating cost is obtained within 2 CPU seconds for an industrial example using the proposed model, which is reduced by 6% compared to that from actual operation.

The vacuum system reform and test of the super-critical 600mw unit

The deficiencies of the designed vacuum system of the super-critical unit is pointed out in this paper, and then it is reformed by the steam ejector. The experimental results show that the vacuum of the condenser can be improved, the coal consumption can be reduced and the plant electricity consumption can be lowered dramatically at a small cost of the steam energy consumption. Meanwhile, the water-ring vacuum pumps cavitation problems can be solved.

Thermodynamic Quasi-Equilibrium Model for the Energetic Performances Analysis of the Air and Air–Steam Gasification of Raw and Pretreated Cotton Stalks by Torrefaction and Carbonization

Numerical and experimental study of the gasification of raw and pretreated (torrefied and carbonized) cotton stalks were investigated. The experimental results were used to calibrate the quasi-equilibrium model by multiplying the equilibrium reaction constant with coefficient varying from 0.01 to 10 and by fixing the methane molar fraction. Values varying from 0.15 to 0.7, 0 to 0.8 and 400 to 900 K were considered for air equivalence ratio (ER), the ratio of steam to fuel (SF) and the temperature of steam respectively. LHV and energy efficiency decreased from 4528 kJ Nm− 3 and 73.5% for the raw cotton stalks to 3984 kJ Nm− 3 and 68.9% for torrefied cotton stalks and to 3815 kJ Nm− 3 and 69.6% for carbonized cotton stalks. The energy efficiency was improved by steam injection to 80, 78 and 75% for the gasification of raw, torrefied and carbonized CS respectively due to the increase of H2 and CH4. The air–steam gasification was more efficient to air gasification at a temperature of steam over than 500 K for raw cotton stalks. However, only the air–steam gasification of pretreated cotton stalks was recommended since it has the net energy efficiency (which consider the steam energy) superior to 60%.

Technical Feasible Study for Future Solar Thermal Steam Power Station in Malaysia

This paper proposed renewable energy which is potential to be used in Malaysia in generating electricity to innovate and improve current operating systems. Thermal and water act as the resources to replace limited fossil fuels such as coal which is still widely used in energy production nowadays. Thermal is also known as the heat energy while the water absorbs energy from the thermal to produce steam energy. By combining both of the sources, it is known as thermal steam renewable energy. The targeted area to build this power station has constant high temperature and low humidity which can maximize the efficiency of generating power.