Two-in-One Fuel Synthetic Bioethanol-Lignin from Lignocellulose with Sewage Sludge and Its Air Pollutants Reduction Effects

Metal catalyst-free selective acetosyringone synthesis from rice straw lignin

In recent decades, due to abundance (second most abundant natural polymer after cellulose) and sustainability, lignin has attracted much interest from different researchers to use as a raw material for producing various value-added materials such as polymer and fuel. In addition to that, the aromatic structure of lignin makes it a suitable candidate for producing platform chemicals with aromatic rings. As a result, lignin depolymerization has become an interesting process to derive different phenolic monomers like vanillin, acetosyringone, and guaiacol. Among them, due to the bioactive characteristics and efficiency of acetosyringone in plant regulatory systems, the production of acetosyringone from lignin has been presented in this work. A green and cost-effective method was developed for the selective formation of acetosyringone via depolymerization of isolated rice straw lignin (RSL) by using metal catalyst-free conditions in the biphasic medium and described. The RSL was characterized with various spectroscopic techniques such as FT-IR, solid-state 13C NMR, XPS, and TGA. The selectivity of synthesized acetosyringone during depolymerization of RSL was checked from GC-MS analysis. The molecular structure and purity of acetosyringone isolated from preparative thin layer chromatography (TLC) were confirmed with the help of 1H NMR and HRMS, respectively.

Thermal Treatment of Biomass: A Bibliometric Analysis—The Torrefaction Case

The aim of the paper was to summarize and discuss current research trends in biomass thermal treatment (torrefaction process). Quantitative analyses were carried out, in which the main countries, research units and scientists were indicated. The analysis showed a clear upward trend in number of publications after 2010. Most scientists on selected topics come from China, USA, Canada, South Korea, Republic of China, Poland (Web od Science—Core Collection (WoS-CC) and Scopus databases). Quantitative analysis also showed that the most relevant WoS-CC categories in the summary are: Energy Fuels, Engineering Chemical, Agricultural Engineering, Biotechnology Applied Microbiology and Thermodynamics and Scopus Subject area: Energy, Chemical Engineering, Environmental Science, Engineering and Chemistry. Thematic analysis included research topics, process parameters and raw materials used. Thematic groups were separated: torrefaction process (temp.: 150–400 °C), hydrothermal carbonization process (HTC) (temp: 120–500 °C), pyrolysis process (temp.: 200–650 °C) and gasification and co-combustion process (temp.: 350–1600 °C). In the years 2015–2019, current research topics were: new torrefaction technologies (e.g., HTC), improvement of the physico-mechanical, chemical and energetic properties of produced fuel as well as the use of torrefied biomass in the process of pyrolysis, gasification and co-combustion. The raw materials used in all types of biomass thermal treatment were: energy crops, wood from fast-growing and exotic trees, waste from the agri-food industry, sewage sludge and microalgae.

Studies on the Gasification Performance of Sludge Cake Pre-Treated by Hydrothermal Carbonization

Proper treatment and careful management of sewage sludge are essential because its disposal can lead to adverse environmental impacts such as public health hazards, as well as air, soil, and water pollution. Several efforts are being made currently not only to safely dispose of sewage sludge but also to utilize it as an energy source. Therefore, in this study, initiatives were taken to valorize sewage sludge cake by reducing the moisture content and increasing the calorific value by applying a hydrothermal treatment technique for efficient energy recovery. The sludge cake treated at 200 °C for 1 h was found to be the optimum condition for hydrothermal carbonization, as, in this condition, the caloric value of the treated sludge increased by 10% and the moisture content removed was 20 wt.%. To recover energy from the hydrothermally treated sludge, a gasification technology was applied at 900 °C. The results showed that the product gas from hydrothermally treated sludge cake had a higher lower heating value (0.98 MJ/Nm3) and higher cold gas efficiency (5.8%). Furthermore, compared with raw sludge cake, less tar was generated during the gasification of hydrothermally treated sludge cake. The removal efficiency was 28.2%. Overall results depict that hydrothermally treated sewage sludge cake could be a good source of energy recovery via the gasification process.

Feasibility Assessment of a Bioethanol Plant in the Northern Netherlands

Due to the exhaustion and increased pressure regarding the environmental and political aspects of fossil fuels, the industrial focus has switched towards renewable energy resources. Lignocellulosic biowaste can come from several sources, such as industrial waste, agricultural waste, forestry waste, and bioenergy crops and processed into bioethanol via a biochemical pathway. Although much research has been done on the ethanol production from lignocellulosic biomass, the economic viability of a bioethanol plant in the Northern Netherlands is yet unknown, and therefore, examined. In this thesis, the feasibility study of a bioethanol plant treating sugar beet pulp, cow manure, and grass straw is conducted using the simulation software SuperPro Designer. Results show that it is not economically viable to treat the tested lignocellulosic biomass for the production of bioethanol, since all three original cases result in a negative net present value (NPV). An alternative would be to exclude the pretreatment step from the process. Although this results in a lower production of bioethanol per year, the plant treating sugar beet pulp (SBP) and grass straw (GS) becomes economically viable since the costs have significantly decreased.