Showing papers on "Surface condenser published in 2016"
TL;DR: In this paper, thermal concentration is used to raise the vapour temperature to 100 °C without the need for costly optical concentrators, which is the state-of-the-art in the solar-driven generation of water steam under one sun.
Abstract: The solar-driven generation of water steam at 100 °C under one sun normally requires the use of optical concentrators to provide the necessary energy flux. Now, thermal concentration is used to raise the vapour temperature to 100 °C without the need for costly optical concentrators.
133 citations
TL;DR: In this paper, a model of a representative air-cooled condenser (ACC) system is developed to explore the potential to mitigate this penalty through techniques that reduce the air-side thermal resistance, and by raising the air mass flow rate.
88 citations
TL;DR: In this paper, the authors investigated the combined effect of inlet evaporative cooling (IEC), steam injection (SI) and film cooling (FC) on the power augmentation of simple gas turbine cycle.
43 citations
TL;DR: In this article, the possibility of effective hydrogen generation by the water steam barbotage through the aluminum melt was demonstrated experimentally and a reactor was created and a burner device with the volumetric matrix was used for melting of aluminum and generation of water steam in the reactor.
35 citations
TL;DR: In this article, an improved configuration of lignite pre-drying using both steam bleeds and boiler exhaust flue gas was proposed in order to reduce the work loss of steam turbine.
32 citations
TL;DR: In this paper, the authors proposed to replace the existing steam condenser with a direct-dry condenser to provide phase change and heat rejection of previous once-through and re-circulation cooling systems, and replace the conventional wet cooling towers with completely dry indirect cooling of the recirculation water stream.
27 citations
TL;DR: In this paper, the authors deal with selecting the mass flow rate of cooling water under variable load of a power unit such that optimum operating parameters of the unit can be achieved by minimizing the total entropy generation rate of the condenser, the LP part of the turbine, and the cooling water pump.
26 citations
TL;DR: In this paper, the authors describe the impact of non-condensable gas (NCG) on heat transfer in a steam turbine condenser (STC) and modelling of the steam ejector pump system (SEPS) by controlling the gas extraction rate through extraction tubes.
23 citations
TL;DR: In this article, the authors provided a single equation for the steam power plant condenser effectiveness in off-design conditions (without any additional heat transfer equations) as a function of three independent parameters, such as cooling water temperature at the inlet, cooling water mass flow rate, and steam temperature, along with corresponding reference parameters.
22 citations
TL;DR: In this article, the effect of adding mist to steam as a coolant fluid was investigated, and the results showed that the efficiency can reach 47.2% at low coolant temperature with a mist fraction of 2%.
22 citations
TL;DR: In this paper, a new measure to improve ACSC performance is proposed by installing diffuser orifice plate under the ACSC platform, where the velocity head converts to the pressure head, and the diffuser hole in the plate contributes to shrink the negative pressure region under ACSC.
01 Jan 2016
TL;DR: The most common configuration of this type involves adding a steam turbine bottoming cycle to the gas turbine as discussed by the authors, which can achieve an energy conversion efficiency of over 60% in a combined cycle power plant.
Abstract: The most effective way of increasing the efficiency of a gas turbine based power plant is to turn it into a combined cycle plant. The most common configuration of this type involves adding a steam turbine bottoming cycle to the gas turbine. Hot gases from the exhaust of the gas turbine are used to raise steam in a heat recovery steam generator and this steam is used to drive a steam turbine. The best plants of this type can achieve an energy conversion efficiency of over 60%. More versatile combined cycle plants can be created by adding additional heating by burning more natural gas in the steam generator. A further configuration uses solar heat add to the heat in the gas turbine exhaust.
TL;DR: In this article, thermal-hydraulics characteristics of the water-jet-centered supersonic SI system were investigated from both experimental and analytical approaches, and the results showed the water jet centered SI's promising functionality as a passive coolant injection in view of its quick-start up, operable condition limits, discharge pressure and heat transfer capabilities at current inlet conditions.
TL;DR: In this article, the effect of the gas turbine, duct burner and heat recovery steam generator on power generation is investigated to reduce exergy destruction and power loss in the turbine, and the sensitivity analysis on ambient temperature, compressor pressure ratio, fuel lower heating value, and duct burner fuel rate, condenser pressure and main pressure are performed and results are reported.
Abstract: The heat recovery steam generator (HRSG) and duct burner are parts of a combined cycle which have considerable effect on the steam generation. The effect of the gas turbine, duct burner and HRSG on power generation is investigated to reduce exergy destruction and power loss in the gas turbine. The results show that with an increase in duct burner flow rate, pressure loss in the recovery boiler increases, steam generation increases on the HP side while it decreases on the LP side. With a reduction in the HP pinch point, thermal recovery increases while the LP pinch point does not have a significant effect. Then, power loss due to pressure drop in the gas turbine and the electricity cost are considered as two objective functions for optimization. Finally, the sensitivity analysis on ambient temperature, compressor pressure ratio, fuel lower heating value, duct burner fuel rate, condenser pressure and main pressure are performed and results are reported. It is concluded that with an increment in compressor pressure ratio, the duct burner flow rate and consequently steam generation increases while electricity cost decrease.
TL;DR: In this paper, a shell and tube type molten salt steam generator was set up, and its thermal performance and heat transfer mechanism were studied, and the authors found that as the inlet water temperature increased, the boiling region in the steam generator remarkably expanded, and then the steam generation rate and energy efficiency both rose with the overall heat transfer coefficient increasing.
TL;DR: In this article, the authors studied the internal temperature distribution in the inner casing of a steam turbine in a combined cycle power plant (CCPP) and found that the highest temperature gradient occurs at the right ending point in the transient process, and then decreases gradually to the steady state value when the temperature of the mixing steam is lower than that of the working steam.
26 Jun 2016
01 May 2016
TL;DR: In this paper, a numerical analysis of the influence of ambient parameters on energy operating indicators of the gas turbine, double pressure heat recovery steam generator and the steam turbine is presented, where the effect of the variation of the ambient temperature on gas turbine electrical power, flue gas stream and temperature at the outlet of turbine is modelled with the use of correction curves.
Abstract: Gas turbine combined cycle power plants are one of the most efficient energy conversion systems. These systems encompass: a gas turbine cycle, steam turbine cycle and heat recovery steam generator. The electrical power of a gas turbine combined cycle power plant heavily depends on ambient parameters — mainly on temperature. A variation of ambient parameters changes the compressor's working point, hence the temperature and stream of the flue gas leaving a gas turbine can be changed. In consequence, boiler efficiency, steam flow and parameters can also be changed. The article presents a numerical analysis of the influence of ambient parameters on energy operating indicators of the gas turbine, double pressure heat recovery steam generator and the steam turbine. The effect of the variation of the ambient temperature on gas turbine electrical power, flue gas stream and temperature at the outlet of turbine is modelled with the use of correction curves. A mathematical model of a heat recovery steam generator is based on mass and energy equations and additional equations which describe the heat transfer process. Unknown parameters which occur in empirical equations have been estimated on the basis of measure results. The model of the steam turbine contains a balance model and a theoretical-empirical model of the steam expansion line in the turbine. The calculation method and exemplary calculation results have been presented.
TL;DR: It is concluded that the lowest steam flowrate is attained using hot liquid reuse and only a single level of steam, but that the presence of additional steam levels resulting from turbines requires a more holistic approach to the synthesis of steam networks.
TL;DR: In this article, a 2-stage solar thermally driven steam jet ejector chiller with latent heat and cold storage driven by motive steam from evacuated tube collectors with compound-parabolic-concentrator (CPC-collectors) is presented.
Patent•
22 Aug 2016
TL;DR: An indirect dry cooling system suitable for steam condensing applications in a power plant Rankine cycle includes an air blast chiller having a plurality of interconnected modular cooler cells, each cell comprises a blower and tube bundle including inlet headers, outlet headers, and plurality of tubes extending between the headers.
Abstract: An indirect dry cooling system suitable for steam condensing applications in a power plant Rankine cycle includes an air blast chiller having a plurality of interconnected modular cooler cells. Each cell comprises a blower and tube bundle including inlet headers, outlet headers, and plurality of tubes extending between the headers. In one embodiment, the tube bundles form an A-frame cell construction being structurally self-supporting from a base. Each of the tubes may be finned. Cooling water circulating in a closed flow loop on the tube side between the air blast chiller and turbine steam condenser is cooled by ambient air blown through the tube bundles. The cooled water flows through a second tube bundle in the condenser which condenses steam. The heated cooling water returns through the air blast chiller to complete the cooling water cycle.
TL;DR: In this article, the influence of non-uniformity of the submerged perforated sheet on steam demand leveling on the evaporation surface is investigated, and a short description of the PGV test facility and a measuring system whose test section is a transverse “cut” of an actual PGV-1000 steam generator with the internals is presented.
Abstract: The results of a calculation and experimental research of the influence of nonuniformity of the submerged perforated sheet on steam demand leveling on the evaporation surface are published in the current article. A short description of the PGV test facility and a measuring system whose test section is a transverse “cut” of an actual PGV-1000 steam generator with the internals is presented. The methods of experimental starts are explained and instrumentations are described. A uniformly perforated sheet with the flow section of 5.7% and a nonuniformly perforated sheet with the flow section of 4.3% on the cold half and 8.1% on the hot half were used in the experiments. The system pressure was approximately 7 MPa, the inlet steam flow rate was varied between 4.23 and 7.94 t/h, i.e., the steam velocity on the evaporation surface was 0.15–0.29 m/s. The experimental results were analyzed with (1) the engineering method based on estimating the flow rates of steam on hot and cold half by the experimental values of the pressure drop on submerged list and (2) the STEG code, which was developed for three-dimensional mathematical modeling of the two-phase thermohydraulics in the heat exchanger volume and upgraded. It was established that changing the perforation from a uniform to a nonuniform one increases the residual nonuniformity coefficient, which characterizes the flow of steam from the hot side to the cold side under the sheet. However, the steam separation becomes worse because of a high local residual nonuniformity coefficients near the border of two plates with different perforation levels.
TL;DR: In this paper, the authors present an approach for energy conversion in the context of a Hitachi Hitachi Power System (HPS) with the aim of reducing the energy consumption of the system.
Abstract: Turbo Machinery Research Department, Research & Development Center, Mitsubishi Hitachi Power System, Ltd. 1-1, Saiwai-cho, 3-chome, Hitachi-city, Ibaraki, 317-0073 Japan, chongfei_duan@mhps.com, koji_ishibashi@mhps.com, shigeki1_senoo@mhps.com Laboratory for Energy Conversion, Department of Mechanical and Process Engineering, ETH Zurich IET, ML J 33, Sonneggstr, 3, CH-8092, Zurich, Switzerland bosdas@lec.mavt.ethz.ch, michel.mansour@lec.mavt.ethz.ch, rabhari@lec.mavt.ethz.ch Department of Mechanical Engineering, Aristotle University of Thessaloniki 54124, Thessaloniki, Greece anestis.kalfas@lec.mavt.ethz.ch
TL;DR: In this article, a miniature heated probe for unsteady wet steam flow field measurements is presented, which has a tip diameter of 2.5 mm, and a miniature heater cartridge ensures uncontaminated pressure taps from condensed water.
Abstract: Modern steam turbines require operational flexibility due to renewable energies' increasing share of the electrical grid. Additionally, the continuous increase in energy demand necessitates efficient design of the steam turbines as well as power output augmentation. The long turbine rotor blades at the machines' last stages are prone to mechanical vibrations and as a consequence time-resolved experimental data under wet steam conditions are essential for the development of large-scale low-pressure steam turbines. This paper presents a novel fast response miniature heated probe for unsteady wet steam flow field measurements. The probe has a tip diameter of 2.5 mm, and a miniature heater cartridge ensures uncontaminated pressure taps from condensed water. The probe is capable of providing the unsteady flow angles, total and static pressure as well as the flow Mach number. The operating principle and calibration procedure are described in the current work and a detailed uncertainty analysis demonstrates the capability of the new probe to perform accurate flow field measurements under wet steam conditions. In order to exclude any data possibly corrupted by droplets' impact or evaporation from the heating process, a filtering algorithm was developed and implemented in the post-processing phase of the measured data. In the last part of this paper the probe is used in an experimental steam turbine test facility and measurements are conducted at the inlet and exit of the last stage with an average wetness mass fraction of 8.0%.
TL;DR: In this paper, the possibility of increasing cogeneration turbine efficiency by using a steam heat pump operating with steam is discussed, where the heat pump energy consumption can be compensated and even exceeded by optimizing the steam expansion process in low-pressure part.
Abstract: Cogeneration turbines operate in different operation modes that considerably differ as to the working process conditions. In summer time, when heat demand is minimal, almost all steam flow passes through all turbine stages and enters into the condenser (condensing mode of operation). When heat supply is needed, the steam bleed-offs are used. The several last stages of the turbine (low-pressure part—LPP) have a control diaphragm at the inlet. When the heat supply is large, the diaphragm is maximally closed, and the entire steam flow, with an exception for a minimal ventilation flow is delivered to the steam bleed-offs (cogeneration mode). LPP flow path is designed for the optimal operation in the condensing mode. While running in cogeneration mode, the LPP operating conditions are far from optimal. Depending on the ventilation steam flow rate and outlet pressure, the LPP power can drop to zero or even become negative (ventilation mode). It is proposed to control an outlet steam pressure by using the heat pump that operates with steam. The heat pump energy consumption can be compensated and even exceeded by optimizing the steam expansion process in LPP. In this respect, operating conditions of cogeneration turbine LPPs during the cold season are analyzed. A brief description of a heat pump operating with steam is made. The possibility of increasing cogeneration turbine efficiency by using a steam heat pump is shown.
Journal Article•
TL;DR: In this paper, the authors deal with the factors or parameters which reduced the efficiency of the condenser and evaluate the performance of the Condenser unit on the basis of site measurement and design data collection performance.
Abstract: The thermal power plants are used to generate power. The thermal power plants are designed based on required conditions (like a good quality of steam, pressure and temperature of steam etc.), but actually inlet conditions are not as per the designed conditions. In practical situations, when power plants are installed there are lots of constraints. This tends to reduce or increase output power and heat rate of thermal power plants. Due to these conditions, the designed power and heat rate are never achieved. Variations in the power outputs from plant are always a matter of disputes. So the parameters for power and heat rate are generated for different conditions of condenser pressure, flow rate of water through the condenser, Temperature difference. On the basis of site measurement and design data collection performance of the Condenser unit can be evaluated. These evaluations indicate that if operating conditions vary, then power output and heat rate also vary. This paper deals with the factors or parameters which reduced the efficiency of the condenser.
Patent•
25 May 2016
TL;DR: In this article, a supercritical water pulverized coal direct oxidation composite working medium circulating power generating system and method is proposed, which is a clean coal utilization power generating technology with great development potential.
Abstract: The invention belongs to the technical field of power generating systems and particularly relates to a supercritical water pulverized coal direct oxidation composite working medium circulating power generating system and method. The system comprises an air separating device, an air compressor, a coal water slurry storage tank, a high-pressure pump, a supercritical water reactor, a solid discharged slag collecting device, a separator, a particle collecting device, a high-pressure gas turbine, a low-pressure gas turbine, a gas pumping device, a steam condenser, a condensate pump, low-pressure heaters, a deaerator, a feed water pump, high-pressure heaters and a preheater. According to the supercritical water pulverized coal direct oxidation composite working medium circulating power generating system and method, the strong oxidation property of supercritical water is fully utilized, fire coal is directly subjected to an oxidation exothermic reaction in the supercritical water, the heat exchange efficiency is improved, and the overall power generating efficiency can be higher than 50%; in addition, no pollutant is discharged, the environmental benefits are good, and the supercritical water pulverized coal direct oxidation composite working medium circulating power generating system and method are a novel clean coal utilization power generating technology with great development potential.
Patent•
12 May 2016TL;DR: In this article, a lignite fired steam power plant comprising a water/steam power cycle and a Lignite dryer system having a heat pump circuit configured and arranged to provide heat energy to the dryer is described.
Abstract: The invention relates to a lignite fired steam power plant comprising a water/ steam power cycle and a lignite dryer system having a heat pump circuit configured and arranged to provide heat energy to a lignite dryer (10) of the dryer system. The heat pump includes a dryer heat exchanger (13), an expansion device (17) and an evaporator heat exchanger (19) connected to the first outlet line (16) so as to enable heat energy transfer from the vapour of the first outlet line (16) to the first working fluid. A compressor (21) is also included in the heat pump circuit. In addition the heat pump circuit is connected to the water/steam power cycle by a steam makeup line (27) from the pressure series of steam turbines and a condensate return line (29).
TL;DR: In this article, the negative pressure region under an air-cooled steam condensers (ACSC) platform was investigated at different wind speeds and directions, and it was found that negative pressure under the ACSC platform results in volumetric effectiveness reduction of the windward fans with increasing wind speed, and hot air recirculation or reversed flow in condenser cells caused a fan inlet air temperature increase.
Abstract: Ambient wind has adverse impacts on the thermal-flow performances of air-cooled steam condensers (ACSCs). It is useful to understand the mechanisms of such influences so as to improve and optimize the performance of condensers. The flow fields around an ACSC at different wind speeds and directions are numerically investigated in this paper. It is found that the negative pressure region under the ACSC platform results in volumetric effectiveness reduction of the windward fans with increasing wind speed, and hot air recirculation or reversed flow in condenser cells causes a fan inlet air temperature increase. Under windy conditions, if a main building blockage effect exists, either hot air recirculation will occur, or else reversed flow may arise. The negative pressure region under the platform plays a leading role in the heat transfer effectiveness reduction. From the scale of condenser cell instead of the whole ACSC, stable backpressures corresponding to the windy conditions are forecasted by the ...