ABSTRACT
Lighter fluids are consumer products used only at a low-volume scale, representing a realizable goal of fossil fuel replacement by renewables. Physicochemical properties of four fossil-based conventional lighter fluids (Ronsonol, Zippo, Landmann, and Terracotta) and six selected biomass-based chemicals (γ-valerolactone, ethyl-levulinate, ethanol, n-butanol, γ-valerolactone 90% v/v and ethanol 10% v/v, and ethyl-levulinate 90% v/v and ethanol 10% v/v mixtures) as potential biomass-based lighter fluids were assessed. Assessments were carried out in terms of safety, toxicological, and environmental viewpoints, represented by a flash point, boiling point, vapor pressure values, and evaporation rates; oral toxicity measured on rats; and real ethanol equivalent values, respectively. Parameters were collected where available; in the absence of literature data, they were calculated or measured and then analyzed. Finally, multicriteria analysis based on the flash point, boiling point, vapor pressure, toxicity, and ethanol equivalent values revealed γ-valerolactone as a renewable substance, which can be a promising alternative to replace fossil-based lighter fluids because it was awarded as the first in the multicriteria evaluation by obtaining the highest value of the overall scores. In practical usage, however, ignition, combustion experiments, flue gas, and emission analysis are also required to underline its commercial use in the future.
ABSTRACT
The replacement of fossil resources that currently provide more than 90% of our energy needs and feedstocks of the chemical industry in combination with reduced emission of carbon dioxide is one of the most pressing challenges of mankind. Biomass as a globally available resource has been proposed as an alternative feedstock for production of basic building blocks, which could partially or even fully replace the currently utilized fossil-based ones in well-established chemical processes. The destruction of lignocellulosic feed followed by oxygen removal from its cellulose and hemicellulose content by catalytic processes results in the formation of initial platform chemicals (IPCs). However, their sustainable production strongly depends on the availability of resources, their efficient or even industrially viable conversion processes, and replenishment time of feedstocks. Herein, we overview recent advances and developments in catalytic transformations of the carbohydrate content of lignocellulosic biomass to IPCs (i.e., ethanol, 3-hydroxypropionic acid, isoprene, succinic and levulinic acids, furfural, and 5-hydroxymethylfurfural). The mechanistic aspects, development of new catalysts, different efficiency indicators (yield and selectivity), and conversion conditions of their production are presented and compared. The potential biochemical production routes utilizing recently engineered microorganisms are reviewed, as well. The sustainability metrics that could be applied to the chemical industry (individual set of sustainability indicators, composite indices methods, material and energy flow analysis-based metrics, and ethanol equivalents) are also overviewed as well as an outlook is provided to highlight challenges and opportunities associated with this huge research area.
ABSTRACT
Geothermal conditions are extremely favourable in Hungary. Thermal water is accessible in 70% of the territory of the country, with a lowest temperature of 30°C. For energetic purposes, it can be utilized in two different ways: for supplying heat or generating electricity. In relation to utilization, one of the most serious problems derives from the chemical composition of thermal water. The present paper investigates the opportunities of preventing scaling by nanofiltration. Experiments were performed on a Thin Film NF DK membrane, thermostated at 50°C and at a pressure of 3.5 MPa with four different samples (from four Hungarian cities - Eger, Mezokövesd, Bogács, Miskolc-Tapolca) using batch plant. Reproducibility of experiments was also investigated using water samples from Komárom at 50 and 60°C. The results showed that NF DK could achieve high retention of divalent ions. The results of the second phase of the experiments proved that water flux and rejections were very stable. After filtration, the scaling properties of thermal water were simulated with the help of chemical equilibrium modelling software, called Visual MINTEQ 3.0. The results of the permeate samples prove that nanofiltration is a successful process in preventing scaling of thermal water for further use.
