Analysis of hybrid separation schemes for levulinic acid separation by process intensification and assessment of thermophysical properties impact

From the time levulinic acid was listed as one of the top-12 building blocks for the sugars-high value compounds conversion, the interest in this compound increased. As part of its possible production route, the definition of viable separation schemes appears of paramount importance in the overall development of levulinic acid exploitation. Hybrid sequences where liquid-liquid extraction is followed by distillation were considered proving how the direct and direct-indirect separation schemes appeared to be the best alternatives in terms of total annual cost and environmental impact. These alternatives were further analyzed to improve their design by complementing the process simulator database with thermophysical experimental values. After obtaining a reliable design for the hybrid direct and direct-indirect configurations used as benchmarks, two intensified al-ternatives were generated. The first intensified configuration is classified as thermodynamically equivalent sequence, while the second one includes a divided wall column. For both, it was achieved a reduction of the total annual cost of 11% without any penalty for the environmental impact compared to the reference case

Modelling the kinetics of supercritical CO2 extraction of biomass

This work addresses the modelling and simulation of the kinetics of CO2 supercritical extraction of oils from biomass. Experimental and simulation results from different matrices and models are presented. gPROMS Model Builder is used to find solutions to three different models applied to study the extraction of three different volatile oils from aromatic plants (coriander, fennel and savoury), and from a bioresidue, industrial grape seeds. The supercritical extraction experiments performed at different temperature, pressure and flow rate conditions provide the data to the modelling studies and for model parameter estimation. The qualitative and quantitative agreement between the experimental and simulated extraction profiles in terms of yields was good for the cases investigated.info:eu-repo/semantics/publishedVersio

Supercritical CO2 extraction of feed stocks to generate high added value bio-products

The huge amounts of waste generated every year by the industry, in addition to the great loss of valuable materials, pose serious organisational problems, both from an economic and ecological point of view. Many of the residues, however, have the potential to be reused and utilized completely via integrated bio-refining technologies. Extraction techniques which play a very important part in biorefineries should provide swift processing and yield quantitative recovery without degradation, complemented by easy separation of extracts from the solvent. In this work, focussed on two generic biomass examples - grape seeds and spent coffee grounds, we outline the perspectives of introducing mild, efficient and with low environmental impact techniques that apply compressed fluids in biorefineries for obtaining high value-added products with a wide spectrum of applications.info:eu-repo/semantics/publishedVersio

Influence of basic agrotechnical activities on the productivity and yield of Triticum monococcumL.

Abstract. The study was conducted during the period 2014 – 2016 in the experimental field of Institute of Plant Genetic Resources, Sadovo. The influence of the period of sowing, the predecessor and the fertilization on the elements of productivity and grain yield per hectare in einkorn wheat were studied. It was established that the structural elements of productivity - number of productive tillers, length of the spike, number of spikelets per spike, mass of central spike, number of grains in central spike, weight of the grains from the central spike are with the highest values in plants grown after predecessor peas, sown in autumn and fertilized with extra nitrogen. With least developed productive capabilities are the plant variants sown in spring after sunflower and without additional fertilization with nitrogen. With proved the biggest impact on grain yield per hectare is the date of sowing. The sources of variation: predecessor and combined effect of factors predecessor x fertilization show equal share of influence on the productivity of einkorn. The results from the study give science-based information on the most favorable time of sowing, fertilizing and predecessor in einkorn

Length of the growing season and yield in Triticum monococcum L., in accordance with the growing conditions

Abstract. The aim of the current study is to trace the changes in the length of the growing season in accordance with the accumulated effective temperatures, rains and plant nutrition during the vegetation period, as well as the influence of these indices on the grain yield. The study was conducted in the period 2015 – 2016 in the experimental field of Institute of Plant Genetic Resources – Sadovo with the local variety B3E0025 from the National Genebank in Sadovo. The experiment was made in block method in four repetitions. Three sowing times were made – autumn, winter and early spring and two options of N fertilization – without additional N and 3 kg/da input of active N substance in tillеring phase. The beginning of the basic phenophases has been observed. As a result of the study it was established that the vegetation period in T. monococcum L. has 114-238 days’ duration and accumulation of effective temperature of 2266.0- 2714.71°C. The length of the growing season and the necessary accumulated temperature depends on the sowing period, the predecessor, the amount of nutrient substances and soil moisture. The extension of the critical phases of autumn sowing favours the obtaining of higher yield. The significance of the effective temperatures decreases with additional N input

Liquid density and critical properties of hydrocarbons estimated from molecular structure

The paper provides new correlations for the estimation of the relative liquid density and critical parameters of hydrocarbons. The correlations employ molecular descriptors from computer simulation of molecular mechanics, which proved valuable in our previous work. High precision is achieved, without the use of unduly complex descriptors and rules, as a result of improved methodology. The new methodology includes a limit upon the functionality of the property database and its predesign by expanding the range and improving the distribution of the repeating structural features in the selected compounds.A compilation of estimated data for the liquid density and critical properties of some hydrocarbons of industrial importance for which no values have been available before is provided