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The structures of phosphate ore particles have great impact on their dissolution behavior. In this work, two kinds of fluorapatite structures in the phosphate ore matrix were identified. The effect of various dissolution process variables including stirring rate, reaction temperature, HCl concentration and phosphate ore particle size was investigated firstly. Then, a structure-related segmented kinetic model for phosphate ore particles dissolution in hydrochloric acid was established to discuss the influence of composition and structure of phosphate ores on the leaching rate. According to the kinetic model, the apparent activation energies were 41.99 ± 0.24 kJ·mol−1 and 46.00 ± 0.35 kJ·mol−1, respectively, for the different type of phosphate ore structures. Based on the kinetics study, the leaching process can be optimized from the point of view of the particle size of phosphoric ore in the industrial applications.

The composite catalyst composed of sulfuric acid and alkyl imidazole-based acidic ionic liquid was used to replace pure sulfuric acid as the catalyst for the synthesis of trioxane. 1-ethyl-3-methylimidazolium hydrosulfate ([EMIM][HSO4]), 1-butyl-3-methylimidazolium hydrosulfate ([BMIM][HSO4]), and 1-hexyl-3-methylimidazole hydrosulfate ([HMIM][HSO4]) were chosen to form composite catalysts with sulfuric acid. The effects of ionic liquid types, formaldehyde concentration (35 ~ 55 wt%), and temperature (353 ~ 368 K) on the reaction were studied. When H2SO4 / [EMIM][HSO4] was used as catalyst with a dosage of 0.6 mol/kg of formaldehyde solution, the optimal catalytic performance was obtained at 373 K with the 50 wt% formaldehyde solution as initial reactant. Compared to that with pure H2SO4 as the catalyst, the trioxane concentration in the reaction system was sharply increased with an increment of 17% by the synergy of ionic liquid [EMIM][HSO4]. The equilibrium constant was increased from 3.08 × 10−5 to 4.19 × 10−5 by the addition of [EMIM][HSO4]. The reaction was intensified by the inhibition of reverse reaction. It indicates that the addition of [EMIM][HSO4] has complicated effects on the reaction. The research results provide a deep understand for the catalytic performance of mineral acid/ionic liquid composite catalysts.

The flow in a liquid falling film is predominantly laminar, and the liquid-side mass transfer is limited by molecular diffusion. The effective way to enhance the mass transfer is to improve the liquid film flow behavior. The falling film behaviors of water, ethanol and ethylene glycol in nine different wavy microchannels were simulated by Computational Fluid Dynamics. The simulation results show that the falling film thickness exhibits a waveform distribution resulting in a resonance phenomenon along the wavy microchannel. The fluctuation of liquid film surface increases the gas–liquid interface area, and the internal eddy flow inside the liquid film also improves the turbulence of liquid film, the gas–liquid mass transfer in falling film microchannels is intensified. Compared with flat microchannel, the CO2 absorption efficiency in water in the wavy microchannel is improved over 41%. Prediction models of liquid film amplitude and average liquid film thickness were established respectively.

In order to concentrate the diluted sulfuric acid from the titanium dioxide (TiO2) production of sulphate process, a new concentration process was proposed by coupling chemical dehydration and multi-effect evaporation. The ferrous sulfate monohydrate (FeSO4·H2O), as the dehydrant, was added to the diluted sulfuric acid to form ferrous sulfate heptahydrate (FeSO4·7H2O) according to the H2SO4-FeSO4-H2O phase diagrams, which partially removes the water. This process was named as Chemical Dehydration Process. The residual water was further removed by two-effect evaporation and finally 70 wt% sulfuric acid was obtained. The FeSO4·H2O can be regenerated through drying and dehydration of FeSO4·7H2O. The results show that FeSO4·H2O is the most suitable dehydrant, the optimal reaction time of chemical dehydration process is 30 min, and low temperature is favorable for the dehydration reaction. 45.17% of the entire removed water can be removed by chemical dehydration from the diluted sulfuric acid. This chemical dehydration process is also energy efficient with 24.76% saving compared with the direct evaporation process. Furthermore, 51.21% of the FeSO4 dissolved originally in the diluted sulfuric acid are precipitated out during the chemical dehydration, which greatly reduces the solid precipitation and effectively alleviates the scaling in the subsequent multi-effect evaporation process.

Aerocellulose with three-dimensional pore structure and amino groups was prepared by free radical grafting polymerization of acrylamide based on the homogeneous ionic liquid system. The effects of reaction temperature, reaction time, initiator dosage, monomer dosage and crosslinking agent dosage on the loading ratio were studied. The aerocellulose was characterized by Fourier transform infrared spectroscopy, elemental analysis, X ray diffraction, scanning electron microscope, thermogravimetric analysis and N2 adsorption–desorption analysis. The adsorption capacity of CO2 was measured on a static adsorption device and the results indicated that adding N, N-methylene-bis-acrylamide (MBA) as a cross-linking agent could increase the loading ratio significantly. The loading ratio could reach up to 38.59% when reaction temperature is 333.15 K, reaction time is 6 h and cellulose:APS:AM:MBA = 1:0.1:6:0.1. Although the specific surface area decreased after grafting process, the CO2 adsorption capacity achieved 1.07 mmol/g at 315.15 K and 190 kPa, while the adsorption amount of ungrafted aerocellulose was only 0.52 mmol/g. Furthermore, the fitting results showed that the CO2 adsorption behavior on ungrafted aerocellulose belongs to physical adsorption process, and the adsorption on grafted aerocellulose belongs to both physical and chemical adsorption process.

The dispersity and the neighboring degree of different sites play crucial roles in the catalytic performance of dual site catalysts. The solution of precursors was encapsulated into microdroplets by forming a microemulsion. The average diameter of microdroplets was about 45 nm. This guaranteed that the dosage of precursors was at the attogram level and only about a thousand precursor molecules were encapsulated in each microdroplet. An anti-solvent extraction method was applied to extract water from the microdroplets with acetonitrile. The precursors co-precipitated in the microdroplets due to the loss of water. The encapsulated precursors in the microdroplets co-precipitated together in nanoscale space, so the neighboring degree of the two precursors was improved significantly. The prepared catalyst was characterized by ICP-OES, BET, XRD, H2-TPR, TEM and XPS. Compared with the Cu–ZnO/Al2O3 (CZA) catalysts prepared by the conventional impregnation method, the CZA catalysts prepared by the proposed strategy had much stronger interaction and a better neighboring degree of the dual active sites. They also showed very good catalytic performance for the reverse water gas shift (RWGS) reaction. The CO2 conversion of the designed CZA catalysts was about 1–2 times higher than that of the CZA catalysts prepared by the conventional impregnation method at 0.1 MPa, 300–400 °C and a CO2/H2 mole ratio of 1.

The CO2 mineralization is an economical route to reduce CO2 emission for the production of high-value carbonate products. The performance of CO2 indirect mineralization of MgSO 4 by ( NH 4 ) 2 CO 3 solution was studied systematically. The effects of process parameters on the reaction performance and morphology of MgCO 3 · 3 H 2 O were investigated. In the reaction process, three stages were observed, including nucleation induction, solid phase growth and equilibrium stage. The nucleation induction period and equilibrium time are shortened with the increase of reaction temperature, initial reactants concentration, stirring speed and ( NH 4 ) 2 CO 3 / MgSO 4 molar ratio. These parameters also play a vital role in the morphology of products. It was found that the difference between crystal growth rate and mass transfer rate has a significant impact on crystal morphology. A kinetic model was derived from the solid phase growth rate. The estimated activation energies of forward and reverse reaction are 30.37 kJ / mol and 32.71 kJ / mol , respectively.

The film thickness is a vital parameter for the falling film micro-reactor (FFMR) as a characteristic value representing both the surface to volume ratio and the distance of mass and heat transfer. In this paper, a method and procedure using a stereo digital microscopy to study the flow pattern and liquid film thickness in the FFMR were developed. The hydrodynamic behaviors of three liquids (deionized water, ethanol and isopropanol) have been investigated in a customer designed FFMR. Studies suggest that the film thickness increases with increasing flowrate and viscosity. The viscous force plays a dominant role in the falling film process. The falling film behaviors were also analyzed by computational fluid dynamics (CFD) simulation. A new correlation for the film thickness prediction has been proposed, and its predictions are consistent with the experimental data from this work and public literatures with an accuracy of 7% and 20%, respectively. As a result, stereo digital microscopy has been proved to be an effective device for investigating the hydrodynamic behaviors in FFMR, and the proposed model can accurately predict the film thickness in falling film micro-system within a wide flow regime.

The reaction mechanism of isobutane/1-butene alkylation is very complicated. Many parallel and competitive reactions exist in the reaction system. Stringent mass and heat transfer is a key to achieve satisfied selectivity and yield for this exothermic and mass transfer controlling reaction process. A microreactor configured with staggered herringbone grooves was adopted for intensifying the mass and heat transfer of this process. The hydrodynamic and mixing behaviors of reactants phase and catalyst phase in the microreactor with different channel size were simulated through Computational Fluid Dynamics. The simulation shows that smaller channel depth results in the relatively better mixing performance. The performance of isobutane/1-butene in the designed microreactor were studied systematically. Comparing with the stirring batch reactor, the designed microreactor provides constant reaction temperature and the reaction time can be shortened significantly to 29 s with 1-butene conversion of 91.4%. Under the optimal reaction conditions, the 1-butene conversion was 94.9%, the selectivity of C8 was 91.08%, and the alkylate research octane number was 99.7. The designed microreactor configured with staggered herringbone grooves is much better than the conventional reactors for isobutane/1-butene alkylation due to its excellent mass and heat transfer performance.

The disposal and resource utilization of waste activated sludge (WAS) is a big challenge for its high moisture content. Ionic liquid (IL), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][OTf]), was innovatively used as a conditioner to improve the dewatering performance of WAS. The WAS was characterized by flocs size, three-dimensional excitation-emission matrix (3D-EEM), zeta potential, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) for the investigation of intensification mechanism. The results showed that the dewatering performance of WAS conditioned by [EMIM][OTf] was significantly improved. The moisture content was successfully decreased to 64.99±0.92 %, and the intensification mechanism was investigated. The results showed that the structures of extracellular polymeric substance (EPS) were destroyed by [EMIM][OTf]. It brought a sharp decrease of the contents of polysaccharides (PS), proteins (PN), humic acid (HA) and fulvic acid (FA) in tightly bound extracellular polymeric substance (TB-EPS) structure. The inactivation of microbial cells promoted the disintegration of flocs. Large flocs were converted into unstable small particles and biopolymers. In addition, the negative charges of WAS were also neutralized for dissolution of biopolymers in [EMIM][OTf], and the electrostatic repulsion between flocs was weakened. [EMIM][OTf] was easily recycled five times. The research results indicate that specific IL, such as [EMIM][OTf], is a potential conditioner to improve the dewatering performance of WAS.

Accurate short-term load forecasting (STLF) is critical to the operation and control of the power grid. In the literature, deep learning techniques have shown its superiority for accurate load forecasting over other methods due to its strong regression ability. However, the training process of the deep learning systems is time-consuming providing that they contain a large number of parameters due to the complex structure. This paper presents a novel broad learning system (BLS) approach for load forecasting. The BLS, which is established as a flat network, is an alternative to the deep learning system by expanding the structure in a wide sense. The expanded broad structure of BLS ensures its strong approximation capability of nonlinear mapping. Moreover, the BLS has a much faster training process compared to deep learning due to its simple structure. The proposed method is tested with an open dataset at low-voltage level from Australia and the testing results demonstrate the effectiveness of the proposed method.

Nowadays, the high penetration of renewable energy in power systems reduces the sharing of traditional synchronous generators, which brings many challenges in system frequency regulation. The demand-side resources e.g the responsive loads can be utilized for power system ancillary services and reserve capacities. In this paper, distributed controlled load aggregators are proposed for power system frequency regulation. A finite-time leader-following communication protocol is proposed for aggregation of load aggregators, where there is a leader to share the power reference and multiple load aggregators to track the requirement. The automatic generation control signal for secondary frequency regulation and local frequency measurement are received by the leader control to generate reference signal. As a result, both the distributed controlled load aggregators and synchronous generators will participate in the power system frequency regulation. The proposed method is tested on a single-area power system under various operation conditions.

Distributed generation (DG) units such as small-scale wind turbines, solar photovoltaic (PV) panels and microturbines have been increasingly installed in microgrids. Since the renewable energy sources (RESs) such as PV systems have reverse-peak power generation, demand response methods have been widely used in the microgrids to achieve peak shaving. Considering DG and demand response, microgrids can be operated in a cost-efficient and secure way. By utilizing a price-based demand response (PBDR) method and dispatching microturbines, this paper develops a two-stage optimal coordination method for microgrids. In a day-ahead stage, the PBDR for the whole day is optimized with consideration of the dispatch of the microturbine power generation. Then, in an intraday stage, the microturbines are dispatched to follow the RES variations. The proposed method is tested on a 33-bus microgrid and the simulation results demonstrate high efficiency in operating cost reduction.

In high renewable penetrated power systems, system frequency regulation and stability is a major challenge. In the demand-side, the thermostatically controlled loads (TCLs) in smart buildings can be exploited for the power system ancillary services including frequency regulation. In this paper, smart buildings with TCLs are proposed for power system frequency regulation services. The smart buildings are aggregated together by leader-follower consensus algorithms with sparse communication infrastructure. Then the distributed aggregation of smart buildings will provide aggregated power response in the load frequency control. The leader’s control signal is generated by both frequency measurement and automatic generation control signal. This method can provide fast, dynamic, and distributed power regulation with fair power and comfort sharing among all participate smart buildings. We have conducted both system contingency and normal operation scenarios to validate the proposed approach.

With the widespread installation of smart meters, more and more residents are signing long-term contracts with the grid for demand response (DR) scheme. As an effective way of managing energy consumption about energy prices and system energy balance conditions, the DR scheme contributes to the system cost-saving. In this context, the optimal operation of a multi-energy residential microgrid (MERMG) is studied considering the multi-energy DR scheme. The objective is to minimize the net operating cost under the system’s operational constraints. In the multi-energy DR scheme, the price-based DR (PBDR) is used for power consumption and thermal (heat or cooling) inertia is for the thermal energy consumption. Besides, to guarantee the solution quality as well as relieve the computation burden, the original nonlinear items are linearized to make the operation model a mixed-integer linear programming (MILP) problem. Then it can be then efficiently solved by commercial solvers like Cplex and Gurobi. Finally, by applying the proposed method in the test MERMG and comparing it with the one without the multi-energy DR scheme, the validity of the proposed method is verified.