Performance Analysis of a Waste-to-Energy System Integrated with the Steam–Water Cycle and Urea Hydrolysis Process of a Coal-Fired Power Unit

An innovative hybrid energy system consisting of a waste-to-energy unit and a coal-fired power unit is designed to enhance the energy recovery of waste and decrease the investment costs of waste-to-energy unit. In this integrated design, partial cold reheat steam of the coal-fired unit is heated by the waste-to-energy boiler’s superheater. The heat required for partial preheated air of waste-to-energy unit and its feedwater are supplied by the feedwater of CFPU. In addition, an additional evaporator is deployed in the waste-to-energy boiler, of which the outlet stream is utilized to provide the heat source for the urea hydrolysis unit of coal-fired power plant. The stand-alone and proposed designs are analyzed and compared through thermodynamic and economic methods. Results indicate that the net total energy efficiency increases from 41.84% to 42.12%, and the net total exergy efficiency rises from 41.19% to 41.46% after system integration. Moreover, the energy efficiency and exergy efficiency of waste-to-energy system are enhanced by 10.48% and 9.92%, respectively. The dynamic payback period of new waste-to-energy system is cut down from 11.39 years to 5.48 years, and an additional net present value of $14.42 million is got than before.

A mathematical model for the virtual simulator of the power unit electrical part

The mathematical model is developed for a virtual training system (simulator) of the power unit electrical part operators of a thermal (nuclear) power plant. The model is used to simulating the main operating conditions of the power unit electrical part: generator idling, generator synchronization with the power system, excitation shifting from the main unit to the backup one and vice versa, switching in the power unit auxiliary system, and others. Furthermore, it has been implemented modelling some probable emergency conditions within a power plant: incomplete phase switching, damage to standard power unit equipment, synchronous oscillations, asynchronous mode, etc. The model of the power unit electrical part consists of two interacting software units: models of power equipment (turbine, generator with excitation systems, auxiliary system) and models of its control systems, automation, relay protection and signalling. The models are represented by the corresponding algebraic-differential equations that provide real-time mapping power unit processes at the operator’s request. The developed model uses optimal solving algebraic-differential equations to ensure the virtual process behaviour in real-time. In particular, the implicit Euler method is used to solve differential equations, which is stable when simulating processes in significant disturbances, such as accidental disconnection of the unit from the power system, tripping and energizing loads, generator excitation loss, etc.

Mitigating Aircraft Auxiliary Power Unit Carbon Dioxide (CO2) Emissions During the Aircraft Turnaround Process from the Use of Solar Power at the Airport Gate: The Case of Moi International Airport, Kenya

One of the most pervasive trends in the global airport industry in recent times has been the adoption of green renewable technologies. Many airports around the world have now installed photovoltaic (PV) solar systems as a key environmental measure. One of the critical areas of energy management at an airport is the provision of power and cooling at the gate, which is used during the aircraft turnaround process. Historically, the aircraft auxiliary power unit (APU) was the primary power source during the aircraft turnaround process. In recent times, airports have transitioned to the use of fixed electrical ground power (FEGP) and preconditioned air to mitigate the emissions from use of aircraft auxiliary power unit (APUs). Based on an instrumental case study research approach, this study has examined how Moi International Airport in Kenya has mitigated the airport’s carbon footprint by using a green, renewable energy system. The study’s qualitative data was examined by document analysis. The case study revealed that Moi International Airport has installed a photovoltaic (PV) solar system with a 500kW capacity that is used to primarily provide solar power at the airport’s apron area. The photovoltaic (PV) solar system has delivered Moi International Airport with an important environmental related benefit as it has enabled the airport to reduce it carbon footprint, as the photovoltaic (PV) solar system has reduced the airport’s carbon dioxide (CO2) emissions by an estimated 1,300 tonnes per annum.

Design of a System Coupling Liquid Air Energy Storage System with Thermal Power Unit

In recent decades, the market share of new energy resources is increasing rapidly; the intermittency of new energy resources became an issue to power grids. One prevailing solution is to install large scale energy storage systems. To make energy storage systems participate better in peak shaving without geographical constraints, the paper put forward a new design of a system that couples liquid air energy system with a thermal power unit to utilize waste heat from the condenser of the thermal power unit; the system is also independent from electricity input when producing electricity.

Deep learning network based lifetime analysis of energy - fed traction power supply converter

This paper presents a life prediction method based on the parameters of the actual operation history data collected by the existing converter power unit sensors. Firstly, the characteristics of junction temperature curves of forced air-cooled radiator and power unit are extracted, and the deep learning neural network architecture is constructed based on the characteristics. Then the thermoelectric coupling model of power unit based on thermal resistance calculation theory is established, and the cumulative loss is obtained from the measured data. The deep learning network is trained and the model prediction is verified. Finally, the power unit loss distribution under different setting temperature thresholds and the correlation analysis with radiator parameters are obtained, which provides a feasible scheme for parameter setting and life prediction.

Analysis of the frequency characteristics of the control system for the processes of fuel supply to the cylinders of the power unit

The idea of monitoring the identity of the cylinder capacities of an internal combustion engine under conditions of incomplete information is proposed and a computer system is built on its basis. The signal of the instantaneous rotation speed of the crankshaft of the power unit was used as input information. In the development of the hardware architecture, injectors with piezoelectric actuators, the principle of direct digital control, and the principle of control with feedback on the state of fluctuations of the crankshaft rotation speed were used. The Laplace transform was used as a mathematical apparatus for analyzing the structural diagram of a computer system for programmed control of the processes of supplying fuel and air to the cylinders of the power unit. Mathematical models of the components of the hardware for controlling the processes of supplying the fuel-air mixture were constructed, and as a result of the analysis of the structural diagram of the computer system, the transfer function was obtained. Using the capabilities of the Matlab software environment, the transient and impulse transient characteristics of the system are obtained, the Nyquist hodograph is constructed, and the logarithmic amplitude-frequency characteristics of the hardware are established. It was found that the frequency characteristics of the mathematical model of a computer system have the necessary dynamic characteristics. Using the method of expansion into simple fractions, an expression is obtained for a discrete transfer function, the coefficients of the power polynomials of which are established using the method of determinants and computational capabilities of the Mathcad software environment. On the basis of a discrete transfer function, a scheme for computer modeling of the process of processing the signal of the instantaneous speed of rotation of the crankshaft by hardware is constructed. The output signal was obtained by computer simulation, as a result of the analysis of which the speed of the hardware for processing the input information was established.

Principal Modernization Solutions for a 300 MW Power Unit to be Converted to Operate at Ultra-Supercritical Steam Parameters

This paper analyses the state of power engineering in Ukraine and the main trends in the development of the world market in the field of converting high-capacity powerful power units of thermal power plants into ultra-supercritical (USC) ones. It is shown that the energy sector of Ukraine requires special attention and the introduction of new modern technical solutions. Worldwide trends indicate that the emphasis is now on increasing the steam parameters before a turbine to ultra-supercritical ones. This allows one both to increase the efficiency of power units and to reduce thermal emissions, fighting the global environmental problem of climate warming. The implementation of this approach is proposed taking into account the realities of the Ukrainian economy and the available technical capabilities of the power engineering industry. This paper presents the results of variational computational studies of the thermal scheme of the 300 MW power unit of the K-300-23.5 turbine to be converted into a USC one. The problem was solved under the condition of maximizing the preservation of the thermal scheme, increasing the efficiency of the power unit and minimizing capital investments during the modernization of the turbine. It was chosen to preserve the regeneration system, as well as the medium-pressure (MP) and low-pressure (LP) cylinders. Considered and calculated were variants with the addition to the existing turbine of a USC cylinder and the creation of a new high-pressure cylinder (HPC) with insignificant changes in its overall characteristics. The results of computational studies showed that the most rational variant for modernizing the 300 MW turbine plant is the creation of a new HPC designed for operation at USC steam parameters as well as the addition to the IPC of a new cylinder with the purpose of increasing the reheat steam parameters while preserving the regeneration system.