Biorefinery is an excellent strategy to deal with the energy crisis and environmental pollution in the new age. Based on biorefinery, low-value biomass resources can be converted into various value-added products. Furfural is one value-added platform chemical from biomass resources, which has important applications in energy, medicine, chemical, and other fields. The industrial production of furfural has come out for nearly one century and is relatively mature nowadays. However, there are still some issues remain to be solved in the industrial production. In order to solve these problems, efforts have been paid on exploring new technologies and progresses. In this paper, the characteristics of furfural were introduced firstly, and the present situation and problems of furfural industrial production technology are summarized, including corrosion of equipment caused by acid catalysts, difficulty in catalyst recycling, water pollution and so on. Then, the research status and problems of furfural preparation by hydrolysis and pyrolysis and the characteristic of the microwave-assisted technology were carefully reviewed. Finally, the future development direction of furfural preparation technology was prospected.
Camellia oleifera Abel shell, as a by-product produced during the processing of Camellia oleifera Abel, was usually discarded or burned. The resource utilization of C. oleifera shell can not only improve its own added value, but also solve the environmental pollution problems caused by it. Based on the existing research, this paper introduced the main functional components of C. oleifera shell and the utilization of C. oleifera shell in material, fertilizer and energy. C. oleifera shell contained tannins, tea saponins, flavones and polysaccharides and other substances, which made C. oleifera shell an ideal raw material for antibacterial, antioxidant, antiviral and other applications. In terms of materialization, the activated carbon adsorbent of C. oleifera shell showed good adsorption effect, but the capacitance material prepared from C. oleifera shell was low in conductivity, and the mechanical properties of wood-based composites were poor. In the aspect of fertilizer, the organic fertilizer and culture medium prepared from C. oleifera shell could obviously improve the soil, improve the quality of fertilizer and promote the growth of seedlings. In terms of energy utilization, the high lignin, hemicellulose and cellulose content made C. oleifera shell have certain advantages in direct combustion power generation, marsh gas production by anaerobic fermentation, bioethanol and bio-oil preparation, but there are some problems such as chloride corrode boiler, lignin is difficult to degrade, low bioethanol yield, low bio-oil yield and so on. In addition, the future utilization direction of C. oleifera shell was prospected. In the aspect of preparing carbon material, the C. oleifera shell need targeted carbonization for capacitor material. In the aspect of wood-based composites, it need to improve the structure and mechanical property. In the aspect functional components utilization, it need to develop high value-added deep processing products and expand production scale. In the aspect of energy, it need to solve the integration problem of biomass conversion process.
Based on the composition characteristics, hazards and treatment methods of biomass tar, the mechanism of catalytic cracking of biomass tar and the research progress in recent years are briefly introduced, and the catalytic conversion mechanism of biomass charcoal (mainly involving cracking, The three reactions of reforming and condensation), the adsorption and reforming of biomass charcoal, and the catalytic conversion process, the catalytic performance of biomass charcoal is affected by factors such as raw materials, cracking temperature, heating rate and residence time. By analyzing the performance changes of biomass charcoal after modification, it is found that the addition of metal promoters or structural modification of biomass charcoal has the potential for high-efficiency catalytic cracking of tar, which provides a direction for further research and development of low-cost composite catalysts.
Based on the study of physical and chemical properties of co-hydrothermal carbonization products of municipal solid waste(MSW) and peanut shell(PS), thermogravimetry(TG) analysis was used to investigate the combustion characterstic and kinetics of co-carbonization products. The results indicated that the TG curves of co-carbonization products presented three weight loss peaks in the combustion, the lost degree of the second weightlessness peak was more than 50% of the total weightlessness. At the same co-carbonization temperature, with the increase of the proportion of peanut shells, combustion reactions were more thorough, TG curves were shifted to the high temperature side gradually. With the increase of heating rate, the ignition, the burnout temperature and the integrated combustion characteristic index improved. There existed synergistic interaction of co-carbonization products in the combustion process. With the increase of co-carbonization temperature(180-260℃), both fixed carbon content and combustion characteristic index S increased first and then decreased, the minimum ignition energy(Eαi) had an opposite trend. In this study, municipal solid waste were mixed with peanut shells at mass ratio of 5:5, under the conditions of co-hydrothermal carbonization temperature 220℃, the heating rate 40℃/min, co-carbonization product had the highest combustion characteristic index(5.727×10-6 min-2·℃-3) and the lowest ignition energy(89.55 kJ/mol).
Corn straw based activated carbon was prepared from corn straw after formed and torrefied by H3PO4 activation and characterized by N2 adsorption, elemental analysis and FT-IR. The results showed that the optimal conditions were the impregnated ratio of 4∶1, the activation temperature of 400 ℃ and the activation time of 100 min. Under these conditions, the yield of activated carbon was 47.78% and the activated carbon showed excellent adsorption capacity with the iodine adsorption value of 864 mg/g, the methylene blue adsorption of 210 mg/g and the caramel decolorization of 100%. The specific surface area and the total volume of activated carbon reached 1 105 m2/g and 0.745 cm3/g, the micropore volume was 0.287 cm3/g, the mesopore volume was 0.354 cm3/g. Meanwhile, the distribution of pore was concentrated within 5 nm, accounting for 73.56%, and the average pore diameter is 2.697 nm. The FT-IR results showed that the crosslinking reaction was occured between H3PO4 and corn straw during octivation and the activated carbon lost some functional groups of corn straw.
The biochars I, R, S and M were prepared at 300, 500 and 700℃ with the grasses of king grass, rice straw, bagasse and corn straw as raw materials, respectively. The effects of different pyrolysis temperatures on the structure and composition of biochar were studied. Results showed that with pyrolysis temperature increasing, the yield of the four kinds of biochars decreased, carbon content and ash content increased. The yields of I, R, S and M at 300℃ were 45.81%, 48.67%, 46.81% and 46.00%, and the yields at 700℃ were 33.95%, 35.47%, 25.42% and 31.23%. The ash contents and I, R, S and M at 700℃ increased by 54.39%, 65.44%, 95.54% and 71.85% compared those at 300℃. The C/N ratio of R, S, and M were increased with pyrolysis temperature increasing, but that of R was opposite. The pH values of the four biochars increased with pyrolysis temperature increasing. The pH values of I, R, S and M at 700℃ were 7.68, 9.87, 7.59 and 9.33. I and S was porosity and the number of pore increased with the increase of pyrolysis temperature. Both R and M formed a certain amount of flocs at 700℃. EDX analysis revealed that the elemental composition of Si was contained higher in R. Infrared spectroscopy showed that with the increase of pyrolysis temperature, the alkane groups, methyl groups (—CH3) and methylene groups (—CH3) of the four kinds of biochars gradually disappear. The biochar structure was dominated by aromatic compounds and oxygen functional groups, and the structure was more stable.
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.
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.
The new low-energy consumption process of corn fuel ethanol developed by our team adopted low temperature liquefaction, synchronous saccharification and batch fermentation of concentrated mash, three-tower differential pressure distillation and molecular sieve dehydration process and waste heat recovery technology from various sections of the plant. At present, it has successfully applied to a number of fuel ethanol distillery. Taking the Heilongjiang Hongzhan Science and Technology Co., Ltd. 300 000-ton fuel ethanol project as an example, the technical characteristics, energy consumption and product quality were compared and analyzed between the new and the traditional process. The results showed that the steam consumption, process water and amount of circulating water of the new process were reduced by 10.26%, 28.09% and 11.11% compared with those of traditional process, respectively. The production of 1 ton fuel ethanol could save 49 kg standard coal; thus 14 700 tons of standard coal could be saved annually and the energy consumption cost of fuel ethanol could be saved by about 8 million Yuan. At the same time, the product qualities of fuel ethanol and corn distiller's grains (DDGS) were in line with the national standards, some indicators were higher than the national standards, such as the purity of ethanol could reach 99.9%, methanol content was as low as 0.01%, crude protein content was 26.1%, crude fat content was 10.5% and the crude fiber content was 8.7%.
Biomass resources are the only organic carbon resources in nature, which can synthesize a variety of high value-added fuels and chemicals. Biomass ethers compounds are one of the most important biomass derivatives. Among them, alkoxymethylfuran ether has been applied to diesel and diesel additives. Especially, 5-(ethoxymethyl)furfural (EMF) has attracted much attention due to its high energy density, low toxicity, good stability and good fluidity. Recent advances in the synthesis of alkoxymethylfuran ether from different biomass materials with 5-(hydroxymethyl)furfural (HMF) as the basic structure were reviewed. The effects of Lewis acid and Brønsted acid on the selectivity of etherification products were discussed. On the basis of summarizing the synthesis methods of alkoxymethylfuran ether, the future development direction of the catalytic system was discussed.
In order to make full use of biomass sunflower stalks, the simultaneous thermal analyzer was used to study the pyrolysis characteristics of sunflower stalks with heating rate as an influencing factor. The Coats-Redfern integral method was used to calculate the main phase pyrolysis kinetic parameters. And the quantitative analysis of pyrolysis products were studied by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The results showed that the pyrolysis process of sunflower stalk could be divided into three stages: preheating and drying, main pyrolysis and charring; as the heating rate increased, the TG curve of sunflower stalk pyrolysis moved to the high temperature zone. In the main pyrolysis stage (125-400℃), the weight loss rate of sunflower stalk was about 85% of the total weight loss, the activation energies (E) were 37.02-40.48 kJ/mol, and the pre-exponential factors (A) were 6.10×102-27.67×102 min-1, the linear fitting correlation coefficients were all greater than 0.97. During the rapid thermal cracking process, 106 characteristic peaks and 86 characteristic substances were detected, which could be divided into 11 categories according to different chemical types. The main characteristic products of thermal cracking were stearic acid(29.991%), palmitic acid(27.642%), n-octadecane(7.185%), methyl stearate(2.239%), isoprene(1.678%).
The thermogravimetric analysis method was used to research the pyrolysis characteristics of chitin with KOH, and the effect of different impregnation ratios on the pyrolysis process was analyzed. The pyrolysis kinetic parameters were obtained by using the Coats-Redfern integral theory. The effect of KOH on the activation energy of the main pyrolysis process of chitin was investigated.The results of thermogravimetric showed that the addition of KOH changed the pyrolysis behavior of chitin, reduced the activation energy of pyrolysis accelerated the reaction rate and promoted the pyrolysis of chitin. Chitin could be fast pyrolysis with KOH at 140℃ and m(65%KOH): m(chitin)=2:1 or 3:1. The calculating results of pyrolysis kinetic parameters indicated that chitin pyrolysis with KOH was a complex reaction.
With the rapid development of automobiles and manufacturing, the demand for lubricant has also greatly increased, and a large amount of waste lubricant has also been produced. Based on the current pollution status of waste lubricant, this article introduced its deterioration process, pollutant composition, and commonly regeneration processes (flocculation, distillation, extraction, hydrotreating, adsorption, etc.). The article introduced the adsorbents, such as clay, activated carbon, fly ash, natural polymer adsorbents and so on and new technologies (electrostatic adsorption) in detail. The overseas and domestic research status of adsorption regeneration were summarized and the merits and demerits of the adsorbents and adsorption technologies were summarized. Therefore, the problems and development trends of waste lubricant absorption regeneration in the future were proposed.
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℃).
Eucommia ulmoides gum(EUG) is a kind of natural polymer material with good biocompatibility, excellent rubber-plastic duality, and good mechanical properties, which has attracted much attention in the field of novel biomaterials in recent years. However, the poor elasticity and miscibility at room temperature have greatly limited its application in the field of functional materials. Therefore, the physical or chemical modification of EUG for broadening its range of applications has become the research hotspot. Combining with the structural characteristics of EUG, the common modification methods, formation mechanism and material properties of EUG by physical and chemical modification were firstly summarized, such as changing the hardness and elasticity of EUG by blending with other materials or epoxidation modification, vulcanization modification, etc. Then, the latest applications of EUG in green tire and road construction, shape memory and self-healing materials, anti-vibration and sound absorption, medical materials, and biodegradable composite are introduced, respectively. Finally, we envision that the EUG will play an increasingly important role in polymer science in future.
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.
Catalytic conversion is an important route for the utilization of the renewable biomass resources, and the construction of highly efficient catalysts is a crucial step for the catalytic conversion of biomass and its derivatives. The hydrogenation conversion of biomass derived carbonyl derivatives into alcohols or ester compounds is an important step during the catalytic conversion processes of biomass. Due to the mild reaction conditions of the transfer hydrogenation process, the heterogeneous transfer hydrogenation catalysts have broad applications in the conversion of biomass derived carbonyl compound platforms. The transition metal zirconium and hafnium are commonly used as active metals for the transfer hydrogenation reaction. This review summarized the preparation of the zirconium and hafnium based transfer hydrogenation catalysts and their applications in the hydrogenation conversion of biomass derived platforms. Firstly, the preparation of the zirconium and hafnium based transfer hydrogenation catalysts were briefly introduced. Then, zirconium oxide or hydroxide, zirconium/hafnium based catalyst with different ligand (hydroxyl, carboxylic acid, phosphonic acid, sulfonic acid, tungsten acid, amine, organic metal skeleton, zeolite molecular sieve) ligand, the double metal catalyst and the comparative analysis of their catalytic performance, cycle stability and structural mechanism were reviewed in detail, and the performances of these catalysts were compared. Finally, the future perspectives of the catalytic transfer hydrogenation of biomass and the construction of the catalysts were prospected.
Fast pyrolysis is one of the most promising methods for the efficient conversion and utilization of biomass. However, the target product, known as bio-oil, is difficult to utilize directly due to its high oxygen content and complex components. Fast pyrolysis of biomass catalyzed by alkaline earth metal oxides is able to remove the oxygen of the pyrolysis products in the form of CO2 and H2O, thereby improving the bio-oil quality. This review summarized the reaction mechanism (ketonization, aldol condensation, ring opening and side-chain scission) involved in the catalytic pyrolysis of biomass with the typical alkaline earth metal oxides-based catalysts. Also, the effects of catalysts (CaO, MgO, alkaline earth metal-based zeolites and activated carbons), raw biomass, pyrolysis temperature, catalyst amount, residence time, catalytic fast pyrolysis method and catalyst deactivation on the yield and quality of bio-oil were discussed. Finally, the application of biomass catalytic pyrolysis for producing high-quality bio-oil was prospected, which was expected to provide a theoretical basis for the utilization of biomass resources.
In order to realize the direct application of olefin cross-metathesis on preparation of long-chain terminal olefin compounds from the crude fatty acid esters of vegetable oils, methyl oleate(MO) and methyl linoleate(ML) were used as raw materials to prepare long-chain terminal olefin compounds 1-decene(CM1), 1-heptene(CM2) and methyl 9-decenoate(CM3) through olefin cross-metathesis reaction. 4 typical Grubbs catalysts, 10 short carbon chain fluid substrates were chosen and different reaction temperature, time, catalyst dosage and moles ratio of substrate as the reaction conditions were investigated and contrasted. The results showed that the second-generation Hovey-Grubbs catalyst(C3) and the second-generation Grubbs catalyst(C2) were suitable catalysts for raw materials MO and ML, respectively. Eugenol was the most appropriate partner among the 10 substrates for producing aim products. The influences of temperature, time, catalyst dosage and ratio of substrate were investigated, the suitable reaction conditions were reaction temperature 0 ℃, time 20-60 min, catalyst dosage 0.5%-1% and the mole ratio of fatty acid ester to substrates 1∶10-1∶20, the highest conversion of MO and ML were 99%, and the yields of CM1, CM2 and CM3 were 80%, 92% and 73%, respectively.
Eucommia ulmoides gum is a valuable strategic resource in China, and it is the core driving force for the development of E. ulmoides. The development of E. ulmoides gum industry can not only improve the status quo of insufficient natural rubber in China, but also provide China with new sources of sufficient reserve rubber, to form a new international natural rubber market pattern with China's E. ulmoides gum emerging industry as the leader. In recent years, although remarkable progress has been made in the industrialization and application development of E. ulmoides gum, it is still far from meeting the needs of the development of the situation. The reason is that the development of the industrial chain of E. ulmoides has some outstanding problems, such as imperfect technology and insufficient funds. In this article, the changes of gum content in leaves, bark and fruit of E. ulmoides during the growth period were described, its extraction technology(alkaline cooking, solvent extraction, microbial fermentation, bioenzymolysis and comprehensive method) and large-scale production status were mainly summarized. At the same time, many problems in the development of the industry such as lack of research fund and team, disconnect between basic research and engineering applications of gum, lack of product standards, and so on, were deeply analyzed and discussed, and advanced suggestions and measures to solve these key problems in the development. In order to help the development and utilization of E. ulmoides gum in system material engineering, and provide reference for the sustainable development of E. ulmoides rubber industry.