Effect of the Pyrolysis Process Applied to Waste Branches Biomass from Fruit Trees on the Calorific Value of the Biochar and Dust Explosivity

Characterization of isolated starch from Isatis indigotica Fort. root and anhydro-sugars preparation using its decoction residues

Isatis indigotica Fort. root (Ban-lan-gen, IIR), a traditional Chinese medicine (TCM), has an ancient and well-documented history for its medicinal properties. Aside from epigoitrin, indole alkaloids, and their corresponding derivatives as medicinal ingredients, it also contains lots of biomass such as starch. Herein, a new starch was isolated from IIR and the physicochemical properties such as amylose content, moisture content, ash content, morphology, thermal properties, and crystallography were characterized systematically. The amylose content of IIR starch was 19.84 ± 0.85%, and the size and shape of starch granules is ellipsoidal shape with sizes from 2 to 10 μm. IIR starch exhibited a C-type pattern and had 25.92% crystallinity (higher than that of corn starch). The gelatinization temperature of IIR starch was 58.68-75.41 °C, and its gelatinization enthalpy was ΔH gel = 4.33 J/g. After decocting, the IIR's residues can be used to prepare anhydro-sugars in a polar aprotic solvent. The total carbon yield of levoglucosan (LG), levoglucosenone (LGO), 5-hydroxymethylfurfural (HMF), and furfural (FF) could reach 69.81% from IIR's decoction residues in 1,4-dioxane with 15 mM H2SO4 as the catalyst. Further, the residues after dehydration were prepared into biochar by thermochemical conversion and the BET surface area of biochar was 1749.46 m2/g which has good application prospect in soil improvement and alleviates obstacles of IIR continuous cropping.

Sustainable Use of Apple Pomace (AP) in Different Industrial Sectors

In many countries, apple pomace (AP) is one of the most produced types of agri-food waste (globally, it is produced at a rate of ~4 million tons/year). If not managed properly, such bio-organic waste can cause serious pollution of the natural environment and public health hazards, mainly due to the risk of microbial contamination. This review shows that AP can be successfully reused in different industrial sectors—for example, as a source of energy and bio-materials—according to the idea of sustainable development. The recovered active compounds from AP can be applied as preservatives, antioxidants, anti-corrosion agents, wood protectors or biopolymers. Raw or processed forms of AP can also be considered as feedstocks for various bioenergy applications such as the production of intermediate bioenergy carriers (e.g., biogas and pyrolysis oil), and materials (e.g., biochar and activated carbon). In the future, AP and its active ingredients can be of great use due to their non-toxicity, biodegradability and biocompatibility. Given the increasing mass of produced AP, the commercial applications of AP could have a huge economic impact in the future.

Study of Parameters and Theory of Sucrose Dust Explosion

To investigate the parameters of sucrose dust explosion, the minimum ignition energy (MIE) and minimum ignition temperature (MIT) were evaluated. The experiments tested the MIE of sucrose dust under different conditions of dust quantity, ignition delay time (IDT), and powder injection pressure (PIP). The experiments tested the MIT of different particle sizes. The results demonstrate that the MIE of sucrose powder under three conditions was an open-up quadratic polynomial. When the dust quantity, the IDT, and PIP were 0.5 g (417 g/m3), 90 ms, and 150 kPa, respectively, the MIE was 58.9 mJ, 62.6 mJ, and 52.4 mJ. The MIT was positively correlated with the particle size of sucrose dust, and the MIT was 340 °C. At the molecular level, the “O–H” bonds of the sucrose molecule hydroxyl groups were broken by the discharge of electrodes or high temperature to generate H2. The combustion of H2 caused the explosion to spread to the surrounding sucrose dust and made the deposited dust rise, forming an interlocking explosion. The explosion would not stop until the dust concentration dropped below the lowest explosion limit. The results of this study can provide guidance for sucrose enterprises to prevent dust explosion accidents.