Yuxin Wen,Wenqing Lv,Yilong Xu,Liangyan Ma,Haoquan Hu,Lijun Jin
Pyrolysis is a potential approach to treat post-consumer waste natural rubber (NR), however, unclear pyrolysis mechanism restricts its actual utilization. In this work, thermal degradation of NR was investigated combining dynamical method with pyrolysis on the infrared-heating fixed-bed reactor. Results show that thermal degradation of NR is an apparently exothermic and multistep reaction, tar yield reaches up to 96.59 wt%. Pyrolysis tar mainly consists of cycloolefin with a small quantity of chain olefins and mono-ring aromatic hydrocarbons. High temperature reduces the cycloolefin yield but promotes the generation of mono-ring aromatic hydrocarbons. Tar is mainly composed of dimer (C10) or trimer (C15) of isoprene with different structures. H type in tar is mainly aliphatic hydrogen. Besides, a possible pyrolysis mechanism based on the β bond breakage was proposed. The work can provide a theoretical basis for direct control of high value-added products during NR pyrolysis and achieve high efficiency pyrolysis of NR.
This study applied three heating pretreatment methods, including far infrared heating (FIH), stir-frying heating (SFH), and microwave radiation heating (MRH), to raw materials before the cold-press extraction of walnut oil (WO). The quality characteristics of WO and walnut protein isolate (WPI) were systematically studied. The results showed that different pretreatment methods significantly affected the physicochemical properties, oxidative stability, and antioxidant activity of WO ( p < 0.05). FIH pretreatment notably improved the yield, antioxidant activity, oxidation stability, and total polyphenol content of WO ( p < 0.05). Significant changes were also observed in the flavor profile of WO across the different pretreatment methods. Additionally, the WPI obtained after FIH pretreatment exhibited higher protein solubility (49.28%), water-holding capacity (4.58 g/g), and emulsion stability (94.63 min). These findings indicate that FIH pretreatment is a simple and effective strategy for producing high-quality WO and WPI. The findings provide technical support for enhancing the quality of WO and WPI in the food industry, while offering a theoretical foundation for the comprehensive utilization and value-added processing of walnut resources.
Yuxin Wen,Zhixian Bao,Zhengzheng Liu,Dekang Li,Haoquan Hu,Lijun Jin
Pyrolysis of waste tire (WT) is an efficient method to convert it into fuels and high-value chemicals. However, the main organic components of tire including natural rubber (NR), styrene butadiene rubber (SBR) and butadiene rubber (BR) usually exert interaction during pyrolysis . To investigate the interactions between different rubbers, individual pyrolysis and co-pyrolysis of three pure rubbers were conducted using an infrared-heating fixed-bed reactor, and the synergy during co-pyrolysis was revealed based on products distribution, tar quality and compositions from pyrolysis of pure rubber and waste tire. The results show that tar yields from rubber pyrolysis exceed 90 wt% and tar compositions are related to the molecular structures of rubbers. Co-pyrolysis between different rubbers promotes gases formation and inhibits char formation. The interaction between NR and SBR facilitates the formation of cycloolefin and chain olefin , but co-pyrolysis of SBR and BR contributes to the aromatic hydrocarbons formation. Similar tar components from pyrolysis of demineralized waste tire as those from pyrolysis of NR/SBR/BR sample indicate that waste tire pyrolysis contains individual pyrolysis and co-pyrolysis of different rubbers. The potential reaction process of WT was also proposed. The insight on interaction between different rubbers will provide a good guide for efficient pyrolysis of waste tire.
危险品化学品经营许可证（带存储）