As a simple and effective biorefinery method, deep eutectic solvent (DESs) treatment was proposed to isolate lignin from lignocellulose. In this study, choline chloride/lactic acid (ChCl/Lac) was applied to extract high-purity and antioxidative lignin. Under the optimized conditions (120 °C for 12 h), the lignin profiling indicated that the recovered lignin had a high purity (94.18%), low molecular weight (Mw 1967 g/mol), and excellent thermal stability as compared with milled wood lignin. The lignin samples were characterized by using Fourier transform infrared spectrometry and nuclear magnetic resonance (NMR) spectra. In addition, the NMR spectra indicated the functional groups of the lignin extracted via DESs were less damaged and the backbone structure was not significantly modified. To further determine the potential application of DES-Lignin, the antioxidant activity was evaluated by radical scavenging ability. The IC50 values of a treatment time of about 12 h was 0.174. As expected, DES-Lignin showed obvious advantage in oxidation resistance. In short, the proposed process was considered as a promising biorefinery strategy for lignin first production.

As an important part of a micro-compressed air energy storage system, the scroll expander directly affects the efficiency of the whole energy storage system. The effects of resistance on the efficiency of scroll expander caused by inlet structure and size are discussed with theory analysis and experimental methods in this paper. Micro-compressed air energy storage system has aroused widespread attention because of its pollution-free, high flexibility, in the community, remote areas power supply. Comprehensive experimental work with the selections of different size and structure of the air inlet of the scroll expander was performed with the cutting angle of air inlet chamber of the scroll expander. The results of the experiments are discussed on how exergy efficiency and inlet flow of the scroll expander were affected resulting from the cutting angles dissected. The results show that a maximum value exists for exergy efficiency of the scroll expander. Therefore, the exergy efficiency of the scroll expander can be effectively improved by enlarging the air inlet port dimension and modifying the size of air chamber.

A high-performance hydrogel was successfully fabricated using xylan-rich concentrated steam explosion liquid (CSEL). The method used was a free-radical graft copolymerization of acrylic acid (AA) and acrylamide (AM) onto a primarily xylan backbone in CSEL, with a redox system of ammonium persulfate/anhydrous sodium sulfite as the indicator and N,N`-methylenebisacrylamide (MBA) as the cross-linker. The effects of independent parameters (the dosages of the indicator, AM, AA, and the cross-linker) on the swelling ratio of the as-prepared hydrogel were studied via an optimal design of the response surface methodology (RSM). Under the optimal conditions (80.9 mg of initiator, 349.6 mg of AM, 988.7 mg of AA, and 9.39 mg of cross-linker), the swelling ratio of the prepared hydrogel (Xyl-AM-co-AA) was 276.6 g/g, which was close to the predicted value (255.7 g). The swelling behaviors of Xyl-AM-co-AA at different temperatures and pH values were also analyzed. The results showed that the swelling ratios varied at different temperatures and pH values, implying their potential use as smart materials. Analysis by Fourier transform infrared spectroscopy and scanning electron microscopy confirmed the cross-linked and hygroscopic behavior of Xyl-AM-co-AA.

Abstract To understand the modifications of lignin in the steam explosion process (209°C, 7 min), lignin samples in native poplar (LP), steam explosion solid residue (LS) and steam explosion liquid (LL) were separated and studied. The lignin samples (LP, LS and LL) were characterized and analyzed by size exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance [carbon 13 numclear magnetic resonance (13C-NMR) and heteronuclear single quantum coherence or heteronuclear single quantum correlation experiment NMR (HSQC) NMR] analysis. The results revealed that the pretreatment induced reductions in amounts of β-O-4′, β-β′, and spirodienone structure, and increases in the syringyl/guaiacyl (S/G) ratio from 1.14 (LP) to 1.70 (LS) and 1.86 (LL). The HSQC NMR spectra also gave more information about the predominance of G and S units, and only small amounts of p-hydroxyphenyl (H) units. Moreover, SEC demonstrated the depolymerization and repolymerization of lignin, which were the main reasons for the increase in the average molecular weight of LS and the decrease in average molecular weight of LL, respectively. In brief, after steam explosion treatment, the lignin structure changed, but the backbone structure was not noticeably modified.

Power generation from renewable energy has become more important due to the increase of electricity demand and pressure on tough emission reduction target. This has brought great impact on grid reliable operation. Wind curtailment often happens when grid can not accommodate more wind power. Various solutions are under investigation and energy storage (ES) is one of the recognized potential ways forward. Among all the ES technologies, Compressed Air Energy Storage (CAES) has demonstrated its unique merit in terms of scale, sustainability, low maintenance and long life time. The paper is to provide an overview of the current research trends in CAES and also update the technology development. The paper has also given a comprehensive review to the work conducted by the researchers in China.

With the increase of power generation from renewable energy sources and due to their intermittent nature, the power grid is facing the great challenge in maintaining the power network stability and reliability. To address the challenge, one of the options is to detach the power generation from consumption via energy storage. The intention of this paper is to give an overview of the current technology developments in compressed air energy storage (CAES) and the future direction of the technology development in this area. Compared with other energy storage technologies, CAES is proven to be a clean and sustainable type of energy storage with the unique features of high capacity and long-duration of the storage. Its scale and cost are similar to pumped hydroelectric storage (PHS), thus CAES has attracted much attention in recent years while further development for PHS is restricted by the availability of suitable geological locations. The paper presents the state-of-the-art of current CAES technology development, analyses the major technological barriers/weaknesses and proposes suggestions for future technology development. This paper should provide a useful reference for CAES technology research and development strategy.

The model for the leakage and diffusion of liquid ammonia tank established using the species transport and reaction module of Fluent in order to investigate the leakage of liquid ammonia due to storage tank failure. The corresponding influencing laws were obtained by changing the height of leakage source and the size of leakage aperture in the simulation. The potential hazard of liquid ammonia reserved at temperature and high pressure or low temperature and low pressure condition was obtained by comparison of simulation results. The results show that the high concentration of gas diffusion on the leeward side will increase with decreasing height of leakage source, the leakage rate of Ammonia tank and the concentration of gas diffusion on the same location increase as the size of leakage aperture increase, the distance and hazards of gas diffusion during the same time will increase with increasing when using storage mode of normal temperature and high pressure under the same leakage condition.