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30 September 2021, Volume 55 Issue 5 Previous Issue   
Research Report
Co-pyrolysis Characteristics and Kinetics of PET and Wheat Straw
Bingtao HU, Zhijian LI
2021, 55 (5):  1-7.  doi: 10.3969/j.issn.1673-5854.2021.05.001
Abstract ( 29 )   HTML ( 1 )   PDF (538KB) ( 24 )  

Pyrolytic behaviors, main pyrolytic products, synergistic effect and kinetics of Guanzhong wheat straw, polyethylene Terephthalate(PET) sample and its blends(mass ratio 1:1) were investigated by TG-FTIR system at heating rate of 20 K/min. The results demonstrated that the initial pyrolysis temperature of PET sample was 375℃ and the maximum weight loss rate(62.87%) occured at the temperature of 454.9℃ and the residual amount was about 19.42%.The weight loss rates of the mixture were 22.9% and 73.9% at the two weight loss peak(339.9 and 444℃), respectively. At that time, the final prolysis residual amount was about 23.52%. There were two synergistic effects(339.9 and 444℃) in the process of co-pyrolysis which enhanced the amount of pyrolysis products of CO, CH4, aromatics, acids, ketones, aldehydes, alcohols, alkanes, phenols and ethers. The heating value and fuel quality of the raw material were enhanced a lot by the co-pyrolysis process. The apparent activation energy of PET in higher than that of wheat straw(86.5 kJ/mol). And the apparent activation energies of the mixture calculated by Coats-Redfern method were 53.6 kJ/mol at low pyrolysis temperature region(258-363℃) and 81.6 kJ/mol at the high pyrolysis temperature region(393-463℃).

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Process Optimization of Synthesis of 1-Decene by Olefin Metathesis of Methyl Oleate
Hengyi SHU, Zhifeng ZHENG, Shuirong LI, Shouqing LIU, Hongzhou HE, Yuanbo HUANG
2021, 55 (5):  8-14.  doi: 10.3969/j.issn.1673-5854.2021.05.002
Abstract ( 29 )   HTML ( 1 )   PDF (565KB) ( 13 )  

1-Decene was prepared through olefin metathesis reaction using methyl oleate (MO) as the vegetable oil model chemistry, the conversion rate of methyl oleate and yield of 1-decene were used as evaluation indicators to explore the effect of reaction temperature, reaction time, catalyst dosage and molar ratio of substrates to MO, finally the optimal conditions were obtained by orthogonal experiment design. The results showed that the substrate eugenol and Grubbs second-generation catalyst (C2) were beneficial to the reaction system. The optimal conditions were reaction temperature 0℃, reaction time 40 min, catalyst dosage 1%, molar ratio of MO and eugenol 1:10, under these conditions the conversion rate of MO and the yield of 1-decene were 96% and 78%, respectively.

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Compounding of Sapindus-saponin and Its Application for Synthesis of Ni(OH)2/NiOOH Composite Materials
Bing HAN, Fei WANG, Zexue LIU, Haixia LIN, Shuhui ZHAN, Chunrui HAN
2021, 55 (5):  15-20.  doi: 10.3969/j.issn.1673-5854.2021.05.003
Abstract ( 18 )   HTML ( 0 )   PDF (5076KB) ( 11 )  

The natural surfactant sapindus-saponin was extracted from Sapindus mukorossi. The composite properties of sapindus-saponin and cationic surfactant cetyltrimethylamine bromide(CTAB) were studied. Sapindus-saponin and composite surfactants were used to prepare nickel hydroxide composite materials by solvothermal method. The effects of solvents, temperatures, and surfactants on the morphology of the materials were investigated. It was revealed that the compound system had obvious synergistic effect. In detail, the CMC and γCMC of sapindus-saponin were 1 g/L and 41.97 mN/m; when the mass ratio of sapindus-saponin to CTAB was 50:50, the CMC and γCMC of systems decreased drastically to 0.18 g/L and 24.63 mN/m, respectively. The morphology analysis and XRD analysis of Ni(OH)2 composites showed that, when sapindus-saponin was used as surfactant in ethanol system under 180℃, the composite materials with uniform pore flower spherical microsphere structures were obtained, which possessed many thick nanosheets. On the other hand, when sapindus-saponin/CTAB compounded system was used as surfactant in ethanol system under 140℃, spherical coral composite micro-nano materials with uniform morphology were prepared. The two different kinds of composite materials were both Ni(OH)2/NiOOH composites.

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Effects of Reaction Conditions on Products Distribution and Characteristics of Hydrothermal Liquefaction of Cornstalk
Yanmei LI, Chunyan TIAN, Pengtao CHOU, Nianze ZHANG, Xueyuan BAI, Weiming YI
2021, 55 (5):  21-29.  doi: 10.3969/j.issn.1673-5854.2021.05.004
Abstract ( 20 )   HTML ( 0 )   PDF (2592KB) ( 32 )  

The hydrothermal liquefaction(HTL) of cornstalk was carried out on a batch-mode reactor under different reaction conditions through orthogonal experiment design. The experimental variables were reaction temperature(250-350℃), time(0-60 min) and solid content(5%-15%). The characteristics of HTL products were analyzed from several levels such as elements, functional groups, the main chemicals and microstructure. The results showed that the optimum conditions for HTL were temperature 300℃, time 30 min, solid content 5%, at which the yields of biocrude oil(BO), solid residues(SR) and others(gas and liquid) were 22.85%, 15.02% and 62.13% and the liquefaction rate was 84.98%. The HTL operational parameters significantly affected the products distribution and conversion. The degradation degree of components was different under different reaction conditions, which resulted in the biocrude oil yields of 8.31%-22.85%, with HHV of 30.56-32.69 MJ/kg, the aqueous phase TOC content of 7 711.5-12 336.0 mg/L and different composition and surface morphology occurring in solid residues. FT-IR results showed that the functional group distribution of bio-crude oils was similar and indicated the species of compounds in biocrude oils under different liquefaction conditions were similar. GC-MS results showed that major compounds of biocruded oil include phenols, ketones, organic acids, aldehydes, alcohols, nitrogen-containing compounds and furans.

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Pyrolysis Kinetic Analysis of Melon Seed Shells Based on Three Algorithms
Ruohan LI, Aimin JI, Duo DU
2021, 55 (5):  30-34.  doi: 10.3969/j.issn.1673-5854.2021.05.005
Abstract ( 20 )   HTML ( 0 )   PDF (493KB) ( 18 )  

The pyrolysis process of the melon seed shell in nitrogen atmosphere was used as the research object by the thermal weight loss method. The main components of the shell of melon seeds are: hemicellulose, cellulose, and lignin. It is assumed that the shell of melon seeds is formed by three independent parallel reactions during the thermal decomposition process, respectively, genetic algorithm (GA) and nonlinear least squares method. (NLS), Gaussian fitting-genetic algorithm (GGA), establish the kinetic model of the pyrolysis of the melon seed shell, the kinetic parameters of melon seed shell during thermal decomposition were solved. The results show that the GGA algorithm has the minimum deviation between the simulated data and the experimental data and the best performance. The deviation is only 1.12%.

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Effect of pH Value on Anaerobic Fermentation Performance of Tartary Buckwheat Residue
Jing ZENG, Hong YANG, Shiqing LIU, Fang YIN, Wudi ZHANG
2021, 55 (5):  35-41.  doi: 10.3969/j.issn.1673-5854.2021.05.006
Abstract ( 17 )   HTML ( 0 )   PDF (517KB) ( 14 )  

Tartary buckwheat residue was used as raw material, and the fermentation broth with different total solid (TS) mass fraction was used to investigate the acidification experiment. After obtaining the mass fraction of acidified TS, it was readded with buffer solution for anaerobic fermentation. The changes of volatile fatty acids in the whole process of anaerobic fermentation were monitored. The results showed that when the mass fraction of TS was 4%, the gas production was good.When the mass fraction of TS exceeded 4%, acidification occurred in the system, which was caused by excessive accumulation of butyric acid. The conversion of butyric acid to acetic acid could be promoted by using buffer solution(30% NaOH solution) to adjust pH value for combined hydrogen and methane production fermentation, which could effectively solve the problem of acid accumulation and improve energy conversion efficiency. Under the same TS mass fraction, the energy conversion efficiency of the combined hydrogen and methane production group (4# and 5#) were 10.8 times and 12.8 times of those of the untreated group (2# and 3#), respectively. Adjusting pH value with buffer solution after acidification not only could quickly restore gas production, but also had a higher gas production rate than other recovery methods, and the gas production rate of TS could reach 1 267 mL/g. Modified Gompertz equation was used for fitting, and it was found that the correlation coefficients R were all above 0.99, and the fitting results were good.

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Optimization of Flash Extraction Technology of Polysaccharide from Leaves of Camellia oleifera Able. and Its Antioxidant Activity
Run YE, Jing CAI, Jinzhe LI, Wei SUN, Jiapeng SHEN
2021, 55 (5):  42-46.  doi: 10.3969/j.issn.1673-5854.2021.05.007
Abstract ( 15 )   HTML ( 0 )   PDF (1713KB) ( 14 )  

On the basis of single factor experiment, the flash extraction process of polysaccharide from the leaves of Camellia oleifera Able. was optimized by response surface methodology, and the antioxidant activity of polysaccharide was investigated. The optimum conditions of flash extraction were as follows: material-liquid ratio 1:30 (g: mL), temperature 81℃, extraction time 75 s. Under these conditions, the extraction rate of polysaccharide was 8.43%. The polysaccharide from the leaves of Camellia oleifera Able. had strong scavenging ability to DPPH·, ·ABTS+ and hydroxyl radicals, with the inhibitory concentration 50% (IC50) values of 1.706, 0.826 and 4.811 g/L, respectively. Therefore, it had good antioxidant activity.

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Preparation and Performance Evaluation of Microalgae Biodiesel
Guojun YANG, Jianli ZENG
2021, 55 (5):  47-52.  doi: 10.3969/j.issn.1673-5854.2021.05.008
Abstract ( 15 )   HTML ( 0 )   PDF (1022KB) ( 12 )  

Microalgae biodiesel was prepared by SRCA process using microalgae crude oil as raw material. The results showed that the density, kinematic viscosity, flash point, sulfur content, sulfate ash, moisture content, mechanical impurities, copper corrosion, cetane number, acid value, free glycerol content and total glycerin of microalgae biodiesel met the requirements of GB/T 20828-2007. There was also a certain gap between the requirements of national standard for blending biodiesel BD100 and the prepared microalgae biodiesel. For example, the carbon residue of 10% bottom(4.03%), oxidation stability(0.85 h, 110℃) and 90% recovery temperature were far from the requirements of national standard, and the cold filter point(34℃) also did not meet the actual use requirements. The cold filter point of the product could be reduced by crystallization filtration or distillation fraction; 90% recovery temperature up to the standard could be obtained by cutting the fraction (the fraction below 180℃); the oxidation stability could be up to the standard (9.5 h) by adding 2 000 μg/g antioxidant, which could meet the requirement of national standard.

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Review Comment
Progress of Itaconic Acid Light Curable Resins
Junna BIAN, Jian CHEN, Guomin WU, Zhenwu KONG
2021, 55 (5):  53-59.  doi: 10.3969/j.issn.1673-5854.2021.05.009
Abstract ( 26 )   HTML ( 2 )   PDF (677KB) ( 18 )  

As a "green technology", the light curing technology which is not only energy-saving, environmental protection but also economical and efficient, has been applied in many fields. The use of natural renewable resources to produce photocurable resins is of great significance to the sustainable development of photocurable technology. As a kind of natural renewable resource, itaconic acid with unsaturated double bond and two carboxyl groups could replace acrylic acid, hexanedioic acid and other petrochemical resources to synthesize various UV light curable unsaturated resins. The synthetic properties of the resin were excellent. The progress of preparation of itaconic acid UV light curable resins was reviewed, including epoxy itaconic acid resin, itaconic acid polyester, itaconic acid polyester acrylate, itaconic acid polyurethane acrylate, etc. The UV light curable resins from itaconic acid would have important application value in the fields of coatings, biomedicine and 3D printing, which could provide a new approach for the high value utilization of biomass products.

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Research Progress in Microbial Conversion Crude Glycerol to High Value-added Products
Lili JIANG, Baowei ZHU, Changli LI, Wei YANG, Fengyi LIU
2021, 55 (5):  60-66.  doi: 10.3969/j.issn.1673-5854.2021.05.010
Abstract ( 16 )   HTML ( 2 )   PDF (574KB) ( 21 )  

With the development of biodiesel industry, the yield of the main by-product crude glycerol, increased year by year. The production of a large amount of crude glycerol not only caused pollution to the environment, but also greatly reduced the market price of refined glycerol. Glycerol was a stable multifunctional compound, which could be used as the raw material for fine chemical synthesis. The conversion glycerol to all kinds of bio-based chemicals by microorganisms has attracted more and more attention because of its environmental protection, sustainable development and other characteristics. In this paper, the aerobic and anaerobic metabolic pathways of glycerol by microbial fermentation were briefly introduced, and the application of the conversion of crude glycerol to 1, 3-propanediol, bioethanol, lactic acid and 1, 3-dihydroxy ketone by microbial fermentation was emphatic analyzed, in order to provide references for the industrial production of platform compounds.

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