Abstract

Today’s dehumidification technologies of compressor-based condensation and desiccant wheel both handle latent heat loads via sensible heat transformation, requiring complex mechanical components and, therefore, not friendly to the humidity regulation in volume-limited space. In this work, we demonstrated a highly performant humidity regulator by separately handle the sensible and latent loads via Peltier coolers and vapor adsorbent. The whole-solid components enable the miniaturization of the mechanical system. The direct path of isothermal dehumidification is practical in climates with high latent loads. We used aluminum-based MOFs with stepwise sorption isotherm for the proof-of-concept. It shows the ability of this humidity regulator to precisely control the supply air states with a single operation that merits further exploitation in variable industrial scenarios.

Abstract

In order to solve the problem of insufficient peak-regulating capacity of the power system after the grid connection of wind power, photovoltaic and other large-scale renewable energy sources, a complementary, coordinated and optimized dispatching strategy for multi-energy storage systems of wind, water and fire is proposed. Based on the current depth peak-adjusting technology, the cost of depth peak-adjusting loss and the cost of steady fuel injection for thermal power units are analyzed. Considering the characteristics of multi-scene wind-solar complementary, a reasonable system effective reserve is determined, and an optimal scheduling model is established with the optimization objectives of maximum consumption of new energy, system operation economy and system operation security. Finally taking the modified IEEE30-bus system as an example, the benders three-stage decomposition method was used to simulate various scenarios and the results demonstrate that the strategy can effectively enhance the accommodation capacity of the new energy power, which verifies the validity of the proposed model.

Abstract

In this study, inter-provincial energy, chemical and carbon markets are modeled for decentralized electricity, methanol and carbon permit trading among provinces in China under a cap-and-trade policy at province-level resolution. Optimization results reveal that China’s national emission targets for electricity generation and methanol production can be achieved through carbon trading in the context of sectorial integration provided by energy-chemical nexus.

Abstract

Accurate state of charge (SOC) estimation is an important evaluation index for battery management system. However, the SOC estimation accuracy is influenced by many factors, in which aging is one of the most important factors. Therefore, real-time parameter identification is necessary for accurate SOC estimation. In this paper, we proposed a dual adaptive extended Kalman filter algorithm for the SOC and parameter co-estimation of liquid metal battery, which is used in the stationary energy storage. Simulation and experiment results prove its superior performance in accuracy compared with conventional methods.

Abstract

The bioenergy with CO2 capture and storage (BECCS) is a promising solution to cut CO2 emissions and will play an important role in achieving the climate goal of 1.5°C. As the properties of biomass varies significantly, it is of importance to understand the dynamic performance when capturing CO2 from biomass fired power plants.This work is to reveal the dynamic performance of chemical absorption. The aqueous solution of monoethanolamine (MEA) was selected as the solution. By using the real flue gas (FG) data , the influence of FG flow rate on CO2 capture were studied by doing dynamic simulations. It has been found that as the FG flow rate decreases, the CO2 capture rate first rose before going down; and the reboiler duty decreased while the energy consumption of CO2 capture increased.

Abstract

As an unconventional organic pollutant, nitrogen-containing organic waste gas is usually highly toxic, and its clean treatment is becoming urgent under the increasingly strict environmental protection require-ments. The nitrogen-containing exhaust gas produced as tar precipitation after cooling down, and it is mostly eliminated by the combustion method to possibly recover heat, but it is easy to produce problems of NOx emission and incomplete combustion. Catalysts for tar oil to convert it as a syngas generally include natural ore materials, transition metals, alkali metals, etc. Synthetic catalysts have controllable physical and chemical properties and are favored because of their high catalytic activity and low price. For the development of an efficient nitrogen-containing organic waste gas to retrieve resources as syngas, the catalyst is a highly important part. The development of catalysts and its process in this aspect is scarce and thus we combed here to provide meaningful guidance for the blossom of catalytic cracking approach.

Abstract

Direct liquid fuel cells offer many advantages of that directly converts chemical energy into electric energy for power generation with easily obtaining fuels without fuel reforming including wastes or pollutants and such oxidants like heavy metals under common conditions. This work summarizes recent advances and progress mainly on the catalysis studies and their mechanism as well as some typical examples of fuel cell’s assemblies or redox pairs. The pioneering works of our laboratory indicated the technology is not only feasible but also applicable. Further investigations are required including fuel cell’s output current density and applicability.

Abstract

Developing high-efficiency and affordable electro-catalysts remains a crucial bottleneck on the way to the practical applications of the electrochemical urea oxidation reaction (UOR) scenarios. In recent years, Ni-based materials have proven to be excellent electrocatalysts for the UOR in alkaline medium. Understanding the characteristics that affect UOR activity and determining the mechanism are of vital importance for the development of UOR electro-catalysts. Therefore, in situ characterization techniques performed under UOR conditions are urgently needed to monitor the key intermediates together with identifying the UOR active centers and phases. Herein, recent advances regarding in situ techniques for the characterization of Ni-based electrocatalysts are summarized, including Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy. The results from these in situ measurements not only reveal the structural transformation of the catalytic species under UOR conditions, but also disclose the crucial role of NiOOH during the UOR. The evidence displayed by identified intermediate product information helps scientists better understand the UOR path and find solutions. Furthermore, those knowledge will provide helpful inspiration and guidance for the further development of high-efficiency UOR catalysts.

Abstract

Real-time topology monitoring brings in high communication investments and operating costs. This paper proposes a real-time topology monitoring method using only voltage magnitude measurements from partial critical buses for real-time communication, which reduces communication requirement and network traffic greatly. A three-step angle-free optimization algorithm framework is designed to estimate current topology. Firstly, we perform load forecasting and power flow calculation to generate enough pseudo measurements, which makes up the lack of real-time measurements. Secondly, weighted least square method and improved extended Kalman filter are used to eliminate static and dynamic noises. These state estimation methods help provide more accurate measurements for topology tracking, especially with plenty of pseudo-measurements and accumulated error caused by load forecasting. Finally, we design an angle-free topology tracking algorithm based on voltage magnitude measurements of critical buses to estimate and correct current topology. Numerical results on IEEE 33-bus case show that our framework with only 10 critical buses reaches a high real-time topology monitoring accuracy F1 of 91.59% and thus can greatly reduce communication requirement.

Abstract

As the boiler characteristics are affected by load change, the traditional control method cannot realize load tracking to control the main steam temperature MST in real time. In this paper a system is designed to control the midpoint temperature to adjust the fuel-water ratio as the major control, and secondary superheating water spray cooling adjustment as minor control. Firstly, in order to meet the coordinated of the power grid and the power plant, the boiler steam turbine coordination control system is established to track load change control the boiler input and steam turbine output signals.And take the outlet water temperature of the water wall as the intermediate point temperature (MPT), obtain the oil-water ratio, load, MPT relationship from the actual equipment data, and establish the MPT nonlinear discrete controller, to reduce the spray water and quickly adjust the main steam temperature. Use the Sailfish algorithm (SFO) to optimizes PID parameters. At the same time, in order to further improve the SFO optimization ability, an initialization method based on chaotic mapping and reverse learning is proposed, to improve the population diversity and global search ability. Finally, to verify the model accuracy, the actual data input to the model, and compared with the actual data. The error between THE MPT and the actual value is 0℃~3℃, and the error between the MST and the target value is -1.7℃~0.3℃. Compared with the traditional PID, the ISFO-PID controller can reduce the steady-state error by 60%, adjust time by 68%, and spray volume by 40%. The self-adaptive tracking control of main steam temperature load is realized, which can significantly reduce the coal consumption rate and improve the power generation efficiency. It has great application value in energy conversion control