Auxiliary Turbine Research Articles

Coordinated control of wind-storage combined with primary frequency regulation and variable coefficient based on wind speed and SOC

The increase of wind power penetration rate will cause the power system to face the problems of lower inertia level and insufficient primary frequency regulation capability, which will seriously affect the system frequency security. Wind turbine generally operate in MPPT mode, and the primary frequency regulation capability is realized through additional control, but when the wind turbine uses the kinetic energy of the rotor to participate in the primary frequency regulation of the system, it will cause a secondary drop in the system frequency. Participating in the primary frequency regulation of the system with the energy storage auxiliary wind turbine can further reduce the depth of the system frequency drop and improve the secondary drop of the system frequency. However, after the energy storage participates in the system frequency regulation, the State of Charge (SOC) will decrease, which will affect the frequency regulation capability of the subsequent energy storage. In view of the above problems, a control strategy of wind and storage participating in the primary frequency regulation of the power system is proposed considering the energy storage recovery strategy. During the primary frequency regulation, the joint output of the wind turbine using virtual inertia control and the Energy storage battery using droop control can effectively suppress the system frequency drop; During frequency regulation, the Energy storage battery is charged using a recovery strategy to ensure that the SOC of the Energy storage battery is in the state of maximum frequency regulation capacity. The three-machine and nine-node model of the wind and storage system is built through RTLAB. The real-time simulation verifies that the joint output of the wind and storage system under the step disturbance increases the minimum value of the power grid frequency drop and increases the minimum value of the frequency secondary drop. It can also be used under continuous disturbances. Realize the recovery of energy storage SOC.

Reversible solid oxide cell coupled to an offshore wind turbine as a poly-generation energy system for auxiliary backup generation and hydrogen production

The coupling of a reversible Solid Oxide Cell (rSOC) with an offshore wind turbine is investigated to evaluate the mutual benefits in terms of local energy management. This integrated system has been simulated with a dynamic model under a control algorithm which manages the rSOC operation in relation to the wind resource, implementing a local hydrogen storage with a double function: (i) assure power supply to the wind turbine auxiliary systems during power shortages, (ii) valorize the heat produced to cover the desalinization system needs. With an export-based strategy, which maximize the rSOC capacity factor, up to 15 tons of hydrogen could be produced for other purposes. The results show the compatibility between the auxiliary systems supply of a 2.3 MW wind turbine and a 120/21 kWe rSOC system which can cover the auxiliaries demand during wind shortages or maintenance. The total volume required by such a system occupy less than the 2%, if compared with the turbine tower volume. Additionally, thermal availability exceeds the desalination needs, representing a promising solution for small-scale onsite desalination in offshore environments.

Common Faults and Response of Auxiliary Steam Turbines in Thermal Power Plant

Common Faults and Response of Auxiliary Steam Turbines in Thermal Power Plant

Operation Optimization and Improvement of Turbine Auxiliaries in Power Plant

Operation Optimization and Improvement of Turbine Auxiliaries in Power Plant

Thermoeconomic evaluation of double-reheat coal-fired power units with carbon capture and storage and waste heat recovery using organic Rankine cycle

Coal-fired power generation units using carbon capture and storage (CCS) can reduce CO2 emissions significantly whereas CCS consumes large amounts of renewable energy, leading to an efficiency penalty. To decrease the steam extraction and promote energy utilization efficiency, this study employs organic Rankine cycle (ORC) to recover the waste heat of reboiler condensate and utilizes the waste heat in CO2 compressed processes to provide energy for carbon capture system. Three technical scenarios are proposed: (1) Coal-fired carbon capture power generation system: the medium-pressure cylinder exhaust is throttled by an auxiliary turbine and exchanges heat with H6 heater to provide energy for a reboiler; (2) Coal-fired carbon capture power generation system using ORC to recover the residual heat of reboiler condensate; (3) Solar-aided coal-fired power generation system using ORC and CCS: waste heat in CO2 compression processes is supplied for a reboiler and ORC recovers the residual heat of reboiler condensate. The energy balance and overall performance of different scenarios are investigated with EBSILON, and the parameter sensitivity of scenario III is conducted. Results reveal that all scenarios improve the thermal performance of the system, and the thermo-economics of scenario III is the best at the heat ratio of 0.4.

Energy, exergy and exergoeconomic optimization of a cogeneration system integrated with parabolic trough collector-wind turbine with desalination

This paper brings together the benefits of a membrane-thermal desalination plant with an integrated system containing parabolic trough collectors and wind turbines in collaboration with the electrical network to produce power and freshwater. This proposed cogeneration system was employed for providing power and freshwater in Chabahar in Iran by three types of desalination system consist of the Reverse Osmosis (RO), Multi-effect distillation (MED), and Thermal Vapor Compression (TVC). Through this novel system, the heat generated in the parabolic trough collector is transferred into the organic Rankine cycle (ORC) to produce power. So, the generated power of the organic Rankine cycle and an auxiliary wind turbine can employ by the Reverse Osmosis unit, and the surplus amount of the electricity can sell to the electrical network. This configuration is enabled to increase the stability of the system, and it ultimately reduces the cost of water production by 23%. Besides, the integration of Multi-effect distillation (MED) and Thermal Vapor Compression (TVC) systems enjoys the rejected waste heat from the condenser to increase the produced freshwater. The obtained results from exergy analysis demonstrated that the exergy destruction of the solar collectors and wind turbines contributed by 39.5% and 22.2%, respectively. The results of multi-objective particle swarm optimization reveal that the exergy efficiency and the cost of freshwater production reach to 26.2% and 3.08 US$/m3, each. The environmental assessments of this system demonstrate that this hybrid system prevents the amount of 52164 tons of CO2 emission per year.

Dynamic Modeling and Fuel Consumption Potential of an Intercooled Regenerative Reheat Gas Turbine Auxiliary Power Unit on Series Hybrid Electric Vehicle

Abstract Gas turbine systems are among potential energy converters to substitute the internal combustion engine in future series hybrid electric vehicle. Fuel consumption of these powertrains strongly relies on the energy converter efficiency, the energy management strategy deployed on-board as well as on the transient operation during start-up phase. This paper presents a dynamic modeling and the fuel consumption calculation of an intercooled regenerative reheat gas turbine system used as an auxiliary power unit on a series hybrid electric vehicle. A vehicle model is developed and an optimization method is proposed to optimize the powertrain operation. It consists of using the dynamic programing as an energy management strategy in order to minimize the fuel consumption and the number of switching On/Off of the power unit. Fuel consumption simulations are performed on the worldwide-harmonized light vehicles test cycle while considering the electric and the thermal comfort vehicle energetic needs. Then, a gas turbine dynamic model is developed, where turbomachinery and heat exchanger components are modeled by taking into account their dynamic inertias. The efficiency, the power, and the fuel consumption are calculated during transient operations. Based on the optimization results of switching ON and OFF the system, the fuel consumption dynamic simulation results are considered instead of the dynamic programming results. A constant power start-up strategy and a constant fuel strategy were investigated. Results show an increase in fuel consumption between 2.4% and 3.8% with the first start-up scenario and between 5.7% and 6.4% with the second scenario, compared with static model.

RBD Model-Based Approach for Reliability Assessment in Complex Systems

Nowadays, system reliability performance represents a key issue in any advanced technology application in order to guarantee ambient, personnel, and system safety. The core of this paper is the reliability block diagram (RBD) generation with the aim of providing project engineers a reliability prediction in the early stages of industrial product development. This study is focused on gas turbine auxiliary systems; these systems include both mechanical items (in particular hydraulic devices such as valves, pumps, and filters) and electronic ones (e.g., sensors, instruments, control logic). Such complex structures are decomposed in single blocks and interconnections to establish their mutual relationship and achieve reliability performance of the whole system. The case study is one of the most important gas turbine auxiliary systems, the mineral lube oil console. The aim of this paper is to introduce a new approach to assess system reliability prediction in presence of redundant and stand-by architectures; redundancy is widely used in industrial applications since it is one of the best techniques to achieve fault tolerance. The proposed method led to the development of a dedicated software tool RBDesigner that semiautomatically generates a RBD starting from the sketch of thermal-hydraulic systems and provides the most important reliability parameters. The use of the proposed tool allows project engineers to reduce time delivery, reduce time for improvements, achieve reliability targets, and guarantee availability performance to the customers. The strengths of RBDesigner were finally validated by a comparison with other commercial software solutions.

Methods for determining the maximum energy area for wind power turbine

The present paper analyses two control methods for wind power systems to achieve optimum performance in terms of energy. The load control methods at wind turbines (WT) to achieve optimal operation, is based on the fact that the energy captured by the wind energy depends significantly on the mechanical angular velocity (MAV). In order to perform a function in the maximum power point (MPP) area, the load on the electric generator (EG) is changed and the power given by the wind turbine estimated. The first method, known as the small perturbation method, is widely used, becoming classic. The second original method consists in determining the optimal angular mechanical velocity ωOPTIM, using a low power auxiliary wind turbine that operates without load, at maximum mechanical angular velocity ωMAX. This value of MAV takes into account the wind speed evolution in time. The method bases on the particularity of the ωOPTIM/ωMAX report that does not depend on the time variation of wind speed values and has a constant value for a given WT.

Application of Turbine Torsional Oscillation Damping Controller to Static Var Compensator

This paper proposes a new auxiliary turbine torsional oscillation damping controller (TTODC) for static var compensator (SVC) to dampen out subsynchronous oscillations in power systems containing series compensated transmission lines. A new TTODC algorithm on the basis of synchronized phasor measurements received from phasor measurement units (PMUs) is presented. The idea of using remote signals obtained from PMU to dampen subsynchronous resonance (SSR) presented, too. An auxiliary TTODC is proposed for a SVC, using the generator rotor speed deviation signal as the stabilizing and remote signal to dampen subsynchronous oscillations. The performance of the controller is verified in a detailed nonlinear system considering eigenvalue analysis and transient simulations. Sturdiness of the controller is examined by applying the disturbances in the system that causes significant changes in generator's operating point. The IEEE second benchmark (SBM) model is used for the analysis and the SVC is simulated using the power system blockset (PSB) in the matlab/simulink environment.

Study on heat integration of supercritical coal-fired power plant with post-combustion CO2 capture process through process simulation

Coal-fired power plant (CFPP) is one of the main sources of anthropogenic CO₂ emissions. Capturing CO₂ from CFPP by post-combustion process plays an important role to mitigate CO₂ emissions. However, a significant thermal efficiency drop was observed when integrating CFPP with post-combustion carbon capture (PCC) process due to the steam extraction for capture solvent regeneration. Thus research efforts are required to decrease this energy penalty. In this study, a steady state model for 600 MWe supercritical CFPP was developed as a reference case with a low heating value (LHV) based efficiency of 41.6%. A steady state model for MEA-based PCC process was also developed and scaled up to match the capacity of the CFPP. CO₂ compression process was simulated to give an accurate prediction of its electricity consumption and cooling requirement. Different integration cases were set up according to different positions of steam extraction from the CFPP. The results show that the efficiency penalty is 12.29% and 14.9% when steam was extracted at 3.64 bar and at 9.1 bar respectively. Obvious improvements were achieved by utilizing waste heat from CO₂ capture and compression process, taking part of low pressure cylinders out of service, and adding an auxiliary turbine to decompress the extracted steam. The efficiency penalty of the best case decreases to 9.75%. This study indicates that comprehensive heat integrations can significantly improve the overall energy efficiency when the CFPP is integrated with PCC and compression process.

Aerodynamic Effect and Power from an Auxiliary Wind Turbine with Selected Motorcycles

Aerodynamic forces on motor cycles are important for its stability and fuel economy. In this paper, two motor bikes with and without wind turbine are tested in a subsonic open circuit wind tunnel. The parameters C D , C L and C S are measured for a Reynolds number (Re) range of 5.61x10 4 to 22.44x10 4 and the angle of attack (alpha) between 0 deg to 30 deg. It is found that there is no or little effect in lift and side forces if a wind turbine installed. Using Microsoft Excel, the functional relationship as third degree polynomial between the drag at alpha=0 deg and Reynolds numbers are proposed. The power loss was found using the air density, speed and frontal area with the corresponding drag coefficient. A comparison has been drawn between the power consumption in drag for the two motor cycles. In terms of power losses, installing a wind turbine is suitable up to a speed less than or equal 55 km/h for racing bike and in all ranges in speed for dirt bike.

ATWS analysis for Maanshan PWR using TRACE/SNAP code

The objective of this study was to use TRACE code to analyze the reactor coolant system pressure transients under LONF ATWS for Maanshan PWR. According to Westinghouse Anticipated Transients Without Trip report, LONF ATWS was considered as the most severe plant condition. The ASME Code Level C service limit criteria of 22.06MPa (3200psig) was assumed to be an unacceptable plant condition in SECY-83-293. In accordance with 10 CFR 50.62, Maanshan NPP has established AMSAC. Unlike the reactor trip system, it automatically initiates the auxiliary feedwater system and turbine trip under conditions indicating an ATWS. Since the ATWS analysis is not specified in the FSAR (Taiwan Power Company, 1982), TRACE code was used to assess the RCS pressure for Maanshan NPP. Analysis results indicate that RCS pressure can be maintained within 22.06MPa with sufficient negative moderator temperature coefficient and normal work of AMSAC and valves.

Non-Catalytic NOx Removal from Gas Turbine Exhaust with Cyanuric Acid in a Recirculating Reactor; Small Scale Evaluation and Industrial Application

<p>A novel SNC technique to remove oxides of nitrogen (NO<sub>x</sub>) from stationary gas turbine exhaust has been investigated and applied. The technique employs the use of cyanuric acid (CYA), a non-toxic, dry powder, combined with the injection of auxiliary turbine fuel and recirculation. During the initial investigation, exhaust, generated by a 150 kW gas turbine, was treated in an insulated recirculation reactor, with a mean residence time of 0.65 to 0.71 seconds and a pressure drop of 660 Pa. In the reactor, autoignition of injected auxiliary gas turbine fuel raises the flue gas temperature to between 700 and 800 ºC. CYA slurry is injected. Temperature rise and NOx reduction occur simultaneously. Load following has been achieved. At all temperatures, significant NO<sub>x</sub> reduction from initial concentrations of 106 to 124 ppm to as low as 18 ppm at 15% O<sub>2</sub> have been observed. However, the process generates N<sub>2</sub>O emissions, which vary from 45 to 163 ppm, increasing with increasing CYA/NOx ratio. The ratio of N<sub>2</sub>O formed to NO removed was found to be between 1 to 1.5 to 1. The performance of CYA ((HNCO)<sub>3</sub>) is compared to that of ammonia (NH<sub>3</sub>) and urea ((NH<sub>2</sub>)<sub>2</sub>CO). A numerical model, which combines a detailed chemical kinetic mechanism with recirculation, has been developed. The model captures all observed trends well and is an invaluable guide to improved understanding of the interactive NO<sub>x</sub> removal process. The process was then successfully scaled up and applied to a variety of industrial 3.7 MW gas turbines and similarly significant NO<sub>x</sub> reduction has been achieved.</p>

Thermodynamic analysis of high-ash coal-fired power plant with carbon dioxide capture

SUMMARY A thermodynamic analysis of a 500-MWe subcritical power plant using high-ash Indian coal (base plant) is carried out to determine the effects of carbon dioxide (CO2) capture on plant energy and exergy efficiencies. An imported (South African) low-ash coal is also considered to compare the performance of the integrated plant (base plant with CO2 capture plant). Chemical absorption technique using monoethanolamine as an absorbent is adopted in the CO2 capture plant. The flow sheet computer program “Aspen Plus” is used for the parametric study of the CO2 capture plant to determine the minimum energy requirement for absorbent regeneration at optimum absorber–stripper configuration. Energy and exergy analysis for the integrated plant is carried out using the power plant simulation software “Cycle-Tempo”. The study also involves determining the effects of various steam extraction techniques from the turbine cycle (intermediate-pressure–low-pressure crossover pipe) for monoethanolamine regeneration. It is found that the minimum reboiler heat duty is 373 MWth (equivalent to 3.77 MJ of heat energy per kg of CO2 captured), resulting in a drop of plant energy efficiency by approximately 8.3% to 11.2% points. The study reveals that the maximum energy and exergy losses occur in the reboiler and the combustor, respectively, accounting for 29% and 33% of the fuel energy and exergy. Among the various options for preprocessing steam that is extracted from turbine cycle for reboiler use, “addition of new auxiliary turbine” is found to be the best option. Copyright © 2011 John Wiley & Sons, Ltd.

Steam driven large multi effect MVC (SD MVC) desalination process for lower energy consumption and desalination costs

It has been published and demonstrated in operating plants that the low-temperature multi effect desalination process (LT MED) when operated on turbine backpressure steam requires minimal energy consumption yielding specific desalination energy costs approaching values of optimal RO energy costs. However due to variations in electricity demand, the operation of large steam turbines at base load is in most cases impractical. As a result, in order to allow variations in electricity supply and full capacity of the desalination extraction, steam extracted from the turbines at higher pressures than the back pressure is commonly used. The extraction steam pressure of these turbines is in the range of 1.5–4.5 barg. (Typically as required for process steam at refineries and for MSF desalination plants). The LT MED process when utilizing such extraction steam incorporates thermo compressors (steam ejectors) in order to take advantage of the excessive extraction steam pressure, thereby increasing the economy ratio of the MED (decreasing energy consumption). Thermo compressors (ejectors) as a rule have a relatively low adiabatic efficiency, thus limiting the potential of the MED to increase the economy ratio even more. In this paper an approach of using a novel large centrifugal compressor driven by an auxiliary steam turbine utilizing the extraction steam is incorporated instead of the thermo compressor for large LT MED plants. The centrifugal compressor and auxiliary turbine having a much higher efficiency than the thermo compressor results in significant energy savings, thus lowering the desalination costs. This paper will also describe the thermodynamic advantages, the specific investment and desalination costs comparison, and the resulting desalination cost reduction potential of the steam-driven multi effect MVC process.

China: CSRC — carbon black

The objective of this study was to use TRACE code to analyze the reactor coolant system pressure transients under LONF ATWS for Maanshan PWR. According to Westinghouse Anticipated Transients Without Trip report, LONF ATWS was considered as the most severe plant condition. The ASME Code Level C service limit criteria of 22.06 MPa (3200 psig) was assumed to be an unacceptable plant condition in SECY-83-293. In accordance with 10 CFR 50.62, Maanshan NPP has established AMSAC. Unlike the reactor trip system, it automatically initiates the auxiliary feedwater system and turbine trip under conditions indicating an ATWS. Since the ATWS analysis is not specified in the FSAR (Taiwan Power Company, 1982), TRACE code was used to assess the RCS pressure for Maanshan NPP. Analysis results indicate that RCS pressure can be maintained within 22.06 MPa with sufficient negative moderator temperature coefficient and normal work of AMSAC and valves.

Component and Procedural Improvements for the T-62T-40-7 Gas Turbine in the LCAC Fleet

The Sundstrand Power Systems T-62T-40-7 Gas Turbine Auxiliary Power Unit (APU) was adapted from an aircraft-borne APU to a marine application on the U.S. Navy’s Landing Craft Air Cushion (LCAC). Although the LCAC APU experienced less operating time than its aircraft version, the environmental conditions that exist cause unusual wear and component failures. Component and procedural improvements have been developed to extend the reliability of the T-62T-40-7 on board the LCAC.

A Variable-Geometry Power Turbine for Marine Gas Turbines

Gas turbines have been accepted in naval surface ship applications, and considerable effort has been made to improve their fuel consumption, particularly at part-load operation. This is an important parameter for shipboard engines because both propulsion and electrical-generator engines spend most of their lives operating at off-design power. An effective way to improve part-load efficiency of recuperated gas turbines is by using a variable power turbine nozzle. This paper discusses the successful use of variable power turbine nozzles in several applications in a family of engines developed for vehicular, industrial, and marine use. These engines incorporate a variable power turbine nozzle and primary surface recuperator to yield specific fuel consumption that rivals that of medium speed diesels. The paper concentrates on the experience with the variable nozzle, tracing its derivation from an existing fixed vane nozzle and its use across a wide range of engine sizes and applications. Emphasis is placed on its potential in marine propulsion and auxiliary gas turbines.

Improving Nuclear Generating Station Response for Electrical Grid Islanding

This paper describes problems associated with the performance characteristics of nuclear generating stations which do not have their overall plant control design functions co-ordinated with the other grid controls. Some design changes to typical nuclear plant controls are presented which can result in a significant improvement in both the performance of the grid island and reduce the need to isolate nuclear units during the disturbance. Four areas of the overall unit controls and turbine governor controls which could be modified to better co-ordinate the control functions of the nuclear units with the electrical grid are discussed. Some simulation results are presented to show the performance of a typical electrical grid island containing a nuclear unit with and without the changes. By reviewing data from two islanding events and supplementing that with computer simulation studies, some conclusions are made. The first of these is that overall unit controllers which are not designed with grid disturbances and islanding requirements in mind can cause frequency control problems. On detection of grid islanding the turbine power should be regulated by the speed governor only while the overall unit controls maintain appropriate operation of the reactor and steam bypass system. As well, turbine auxiliary governors whose settings and time delays are not co-ordinated with the operation of the main governors and underfrequency load shedding relays on the system can cause frequency oscillation and limit cycles. Turbine auxiliary governor design and settings should be co-ordinated with other grid controls, including other unit governors.