•Solarized gas turbine cycle combined with two-stage fuel reforming is proposed.•Low temperature reforming by exhaust heat and high temperature by solar energy.•Two-stage reforming upgrades energy levels of turbine exhaust and solar energy.•Thermodynamic analyses and comparisons with other systems are conducted.•The thermal efficiency and solar share can reach 47.7% and 75%, respectively.There is insufficient literature about solarized gas turbines that achieved high efficiency and solar share simultaneously. It is because the outlet temperature of a solar receiver is always much lower than a combustor and it is difficult to design a high-efficiency exhaust-heat recovery system except for a complicated Rankine cycle. A solar-assisted chemically recuperated gas turbine system is proposed and expected to achieve a good performance by combining with two-stage fuel-steam reforming. The first stage is a low-temperature reformer, recovering exhaust gas heat, and the second stage is a high-temperature one, absorbing concentrated solar radiation. Thermodynamic analyses and comparisons are conducted. This system is expected to have a competitive thermal efficiency of 47.7%, which is 10.6 percentage points higher than that of a solarized gas turbine system without reformers. Meanwhile, it has a solar share of 75.0%, which is 12.8 percentage points higher than that of a solarized gas turbine system with a low-temperature reformer. In the viewpoint of energy level, the two-stage fuel reforming upgrades low-level thermal energy of the turbine exhaust and solar receiver into high-level chemical energy, reducing exergy destruction. The relative upgrade of energy level is 38.2% for turbine exhaust and 17.4% for solar thermal energy.

•Characteristics of four typical ash deposition forms is analyzed.•Ash belts form at low voltages and will overlap to form ash ribs when T ⩽ 500 °C.•Smooth slope type ash layer forms at high voltages when T ⩾ 500 °C.•Thickness growth rate of a given point decreases with the increasing time.•Back corona discharge onset voltage decreases with ash layer thickness lineally.The high-temperature electrostatic precipitator (ESP) is a potentially efficient method for hot-gas cleaning in advanced technologies, e.g., the coal-staged conversion poly-generation system and IGCC. This paper investigates the characteristics of the ash layer on the internal surface of the anode pipe of a wire–cylinder ESP at temperatures ranging from 350 °C to 700 °C, including ash deposition forms, growth of ash layer and the effect of ash layer on back corona discharge. There are four typical ash deposition forms: the belt form, the slope with ribs form, the slope form and the slope with a thick bottom edge form. Ash layer thickness generally decreases with increasing height. When T ⩽ 500 °C, ash belts form under low port voltages, and with increasing port voltage, they will overlap each other to form ash ribs. When T ⩾ 500 °C, particles are deposited in the smooth slope form if the port voltage is great enough. When T ⩾ 700 °C, a thick bottom ash edge occurs. Ash deposition forms can vary under different operating conditions. As the operating time increases, the thickness growth rate at a given point decreases, and the ash layer height increases because of the repulsive electrical force between the ash layer and the particles. Back corona discharge always occurs on the thickest portion of the ash layer first. The back corona discharge onset voltage decreases nearly linearly with increasing ash layer thickness, from 19,787 V to 17,197 V as the maximum thickness of the ash layer increases from 0.34 to 2.02 mm when T = 500 °C, Up = 17,200 V and min = 650 mg/N m3.

•Properties of negative wire–plate DC corona discharge of up to 1173 K are studied.•Ratio of electron current to total current increases with temperature and voltage.•Corona discharge becomes unstable at 1073 K for a discharge gap less than 50 mm.•Wide discharge gaps and wire electrodes are suggested for high-temperature ESPs.High-temperature electrostatic precipitators for removing dust from fuel or flue gases were proposed to improve energy efficiency or to avoid damaging downstream equipment. This paper attempts to provide a comprehensive understanding of negative DC corona discharges and find ways to increase corona stability at high temperatures. The characteristics of corona discharges were studied in a wire–plate discharge configuration under different discharge gaps and electrode geometries at temperatures ranging from 293 K to 1173 K. The V–I characteristics were analyzed, including corona onset/spark voltages, operating voltage ranges, and corona current compositions. The discharge current density increases as the temperature increases, and the electron-carried current becomes significant at high temperatures. For example, the electron-carried current makes up ∼40% of the total discharge current at 1073 K under an applied voltage of 10 kV. The applied voltage range decreases as the temperature increases. The corona discharges become unstable, and localized breakdowns occur frequently when the temperature exceeds 1073 K and the discharge gap is less than 50 mm, because the ionization coefficient and the number of electrons greatly increase. The operating voltage range increases from 8.2 kV to 13.6 kV at 1073 K when the discharge gap increases from 30 mm to 70 mm. Compared with the wire and spiral electrodes, the ribbon electrodes produce sparks more easily. The wire diameter has little influence on the spark voltage and corona stability at high temperatures.

Attrition is very important in fluidized-bed reactors, especially for limestone-based sorbents used to capture SO2 and CO2. The initial size distribution of the sorbent particles is commonly used to predict the rate of attrition, but the distribution changes during the process. Limestone samples of narrow particle size distributions (PSDs) were tested in an ASTM air-jet attrition apparatus, and the evolution of the PSDs was investigated. The entropies of information on log-normal functions, a measure of the disorder of particles being entrained into the jets, remained almost unchanged during the attrition process. This indicates that particles of greater entropy generally experience attrition at a greater rate in an air-jet apparatus, except for particles which are too large to be mobilized or too small to stay in the bed.

•Provide an analytical method for DC negative corona discharge at high temperatures.•Both corona and drift regions are considered in the analytical method.•Corona region is divided into ionization and attachment layers.•Calculated results are in good agreement with experimental results.This paper proposes an analytical solution for DC negative corona discharge in a wire-cylinder device based on experimental results in which both the corona and drift regions are considered; this approach aims to provide a theoretical method for analyzing electrostatic precipitation at high temperatures. The inter-electrode space is divided into three zones, namely, the ionization layer, the attachment layer (corona region) and the drift region, to investigate the space charge concentration and the electric field distribution. The boundary of the ionization layer is assumed to be the radius at which the rate of ionization balances that of electron attachment. The radius where the value of E/N equals 110 Td is recommended as the boundary of the attachment layer. It was determined that an increasing temperature leads to a decrease in the largest space charge number density and the largest electric field in the drift region that can be provided by a discharging device. With respect to the device in the present work, when the temperature increases from 350 °C to 850 °C, the largest electric field decreases from ∼9 × 106 V/m to ∼3 × 106 V/m, and the largest charge number density decreases from ∼1.3 × 1015 m−3 to 6.4 × 1014 m−3. The radius of the corona region, the space charge number density and the electric field increase as the applied voltage increases at a given temperature. For example, at a temperature of 550 °C, when the applied voltage increases from 10,500 V to 18,879 V, the radius of the corona region increases from ∼2.9 mm to ∼4.9 mm. It appears to be unreasonable to use a constant value that is calculated from Peek's formula as the electric field at the surface of the cathode under all of the conditions.

Experiments were carried out with limestone particles of several narrow size intervals (125–180, 250–300, 355–425, 500–600, 600–710, 710–850, and 850–1037 μm) for times ranging from 0.5 to 144 h in a high-velocity jet apparatus to provide a more comprehensive understanding of jet attrition. The theory of cumulative damage for fatigue is applied to explain the particle attrition mechanisms and to build an attrition model. Fines generation processes differed for limestone particles of different initial sizes, especially in the initial stage, because of the effects of rough surfaces and cumulative damage needed for attrition. In the model, the fines generation rates in the initial stage was well fitted by an exponential function with an index inversely proportional to the particle volume until stable stages were reached, whereas the rate of fines generation during the stable stage appeared to be constant for narrowly sized limestone particles.

•Differential evolution, genetic algorithm and adaptive simulated annealing is used simultaneously.•Multi-objective optimization of Stirling engine is carried out for three conflicting objectives.•Five decision variables are optimized for maximum efficiency, output power and minimum power loss.•TOPSIS and SAW decision making methods are applied for best optimal Pareto front points in search space.Stirling engine has become preferable for high attention towards the use of alternate renewable energy resources like biomass and solar energy. Stirling engine is the main component of dish Stirling system in thermal power generation sector. Stirling engine is an externally heating engine, which theoretical efficiency is as high as Carnot cycle's, but actual ones are always far below compared with the Carnot efficiency. A number of studies have been done on multi-objective optimization to improve the design of Stirling engine. In the current study, a multi-objective optimization method, which is a combination of multiple optimization algorithms including differential evolution, genetic algorithm and adaptive simulated annealing, was proposed. This method is an attempt to generalize and improve the robustness and diversity with above three kinds of population based meta-heuristic optimization techniques. The analogous interpreter was linked and interchanged to find the best global optimal solution for Stirling engine performance optimization. It decreases the chance of convergence at a local minimum by powering from the fact that these three algorithms run parallel and members from each population and technique are swapped. The optimization considers five decision variables, including engine frequency, mean effective pressure, temperature of heating source, number of wires in regenerator matrix, and the wire diameter of regenerator, as multiple objectives. The Pareto optimal frontier was obtained and a final optimal solution was also selected by using various multi-criteria decision making methods including techniques for Order of Preference by Similarity to Ideal Solution and Simple Additive Weighting. The multi-objective optimization indicated a way for GPU-3 Stirling engine to obtain an output power of more than 3 kW and an increase by 5% in thermal efficiency with significant decrease in power loss due to flow resistance.