J. Olt

Basis of energy crop selection for biofuel production: Cellulose vs. lignin

ABSTRACT This paper investigates the suitability of Jerusalem artichoke (Helianthus tuberosus L.), fiber hemp (Cannabis sativa L.), energy sunflower (Helianthus annuus L.), Amur silver-grass (Miscanthus sacchariflorus), and energy grass cultivar (cv) Szarvasi-1 for biofuel production in Northern climatic conditions. Above ground biomass, bioethanol production yield, and methane production yield are used as indicators to assess the bio-energy potential of the culture. Results presented show that energy crops of Southern origin produce 30–70% less biomass than in the origin region. Nonetheless, both perennial and annual energy crops produce high above ground biomass yields (660–1280 g m–2) for Northern climatic conditions. Experimental results show that bioethanol yield is dependent on cellulose content of the biomass. The higher the cellulose content, the higher the bioethanol yield. The biogas production on the other hand, depends on lignin content. The lower the lignin content the higher the biogas yield. Therefore, the selection of the energy crop for bioethanol production should be based on high cellulose content, while for biogas production it should rather be based on the low lignin content.

Dynamic simulation of chip formation in the process of cutting

This work examines the simulation of chip formation during the process of cutting. An analysis of complex rheological models enabled a set of assumptions to be considered, thereby substantiating a hypothesis relating to the chip formation process. The studies demonstrated that the chip formation process, taking into account the plastic deformation and destruction of metal in the local zone, is most appropriately represented by a rheological model in the form of a series connection of elastic-ductile-plastic relaxing medium of Ishlinskiy (reflecting the process of primary deformation of metal from the cut off layer) and the medium of Voigt with two elastic-dissipative elements (representing the process of deformation and frictions from the convergent shaving). The attained complex rheological model served as the basis for constructing a representative dynamic model for chip formation process.

Nitrogen explosion pretreatment of lignocellulosic material for bioethanol production

ABSTRACT A novel method for the pretreatment of lignocellulosic material is investigated in this work, using floodplain meadow hay as a feedstock for bioethanol production. Pressurized nitrogen (N2) pretreatment is combined with explosive decompression to achieve high glucose yields with simple technology and low energy input. Results show that N2 explosion yields hydrolysis efficiencies up to 71.8%. The highest hydrolysis efficiency was achieved at a temperature of 210°C with a cellulose to glucose conversion rate of 195.1 g kg−1 of biomass.

State of the Art on the Conventional Processes for Ethanol Production

Abstract The present review deals with bioethanol as an important food processing, chemical, pharmaceutical, and perfume raw material that is obtained by conventional processes. The continuous development of the conventional production methods of ethanol is caused by the changing raw materials used for the production. The changing raw materials have resulted in the changing of conventional production process of ethanol. The two main production methods of ethanol are chemically synthesized ethanol and ethanol recovery from fermentation of carbohydrates. Today, the most important raw material used in the development of conventional production methods of ethanol is lignocellulose material. However, this gives rise to the need for developing novel solutions for raw materials, especially for pretreatment, to improve efficiency. The chapter gives an overview of the most widely used production processes and development trends in the production of ethanol.

Intensification of rapeseed drying process through the use of infrared emitters

The theoretical basis of the agricultural material drying techniques has been formed in the world for two and a half centuries. Nevertheless, despite the multitude of studies well presented in the literature, the industry still lacks universally recognized methods of design calculation for the majority of drying problems. Presumably, this is due to the fact that the dehydration of foodstuffs is one of the most energy-intensive and complicated work processes. In the process of thermal treatment during the drying, the physical state of the water in the treated item changes, the properties of the item itself are altered. Recently, the drying of foodstuffs by means of infrared (IR) radiation has been gaining ever wider acceptance. At the same time, the technologies for dehydrating foodstuffs and materials are now far ahead of the theory of drying. Not only the classical literature on the drying problems, but even special studies on the subject cannot provide any specific recommendations for the design of installations with the electro-magnetic principle of energy input. Whereas that is exactly the type of installations that are now actively making headway, while offering serious challenges in their modelling. For that reason, experimenting has until now been the only reliable way of their studying. Despite the available extensive scientific literature on the drying, including works on IR units, the practical issues of engineering IR driers have not been tackled. All the existing studies consider solely particular cases. This study discusses the process of drying the fixed bed of rapeseeds with the use of the electromagnetic infrared emitter. The energy intensity of the process and the optimum thickness of the product bed are determined. The aim of the paper is to examine the effect that the operating condition parameters (energy input intensity, temperature, grain bed thickness) have on the drying kinetics and the energy characteristics of the process. The methods of research are based o experimental studies were carried out with the use of monitoring and measuring equipment, upto-date methods and instruments, including solutions developed by the authors. The analytical treatment was performed with the use of the software packages: MathCAD, Excel. The sample testing and examination took place in the laboratory and the methods were in compliance with the applicable standards. A comprehensive experimental investigation of the effect that the operating parameters (specific load and power) have on the rape seed IR-drying kinetics had been accomplished

Pre-surface preparation features when applying wear resistant composite sprayed coatings

in this paper we consider the use of composite metal sprayed coatings for the improvement of the abrasion resistance levels in the working surfaces of friction couples. it is noted that pre-surface preparation, which provides the proper surface roughness that improves the adhesion of the coating to the base, is an important processing step prior to applying such coatings. As a method which enhances the adhesion strength of the sprayed coating, we consider the jet-abrasive (shotblasting) treatment to be ideal. the object of our research was the compression piston rings the internal combustion engine with a composite steel-molybdenum coating. such coatings provide high abrasion resistance for the rings of a good many large-sized engines. the research that has been carried out allowed the conclusion to be reached that the surface roughness depends on abrasive blasting modes, and that it impacts upon the strength of adhesion between the coating and the base. We proposed the jet-abrasive processing modes, which provide the required roughness to the working surface of the piston ring before spraying. keywords: composite coatings, wear resistant sprayed coating, surface roughness, adhesive strength, abrasive jet machining, piston rings. kulcsszavak: kompozit bevontok, kopásálló szórt bevonat, felületi érdesség, tapadószilárdság, abrazív vízsugaras megmunkálás, dugattyúgyűrű. Jüri Olt, DSc. Professor at estonian university of Life sciences. His main research areas are fundamentals of production enginering, materials cutting and design of technological machinery. Viacheslav V. MakSarOV, DSc. Professor at saint-Petersburg mining university, Head of Department of mechanical engineering since 2012 and Dean of electromechanical Faculty since 2015. spezializes in the field of dynamics of machining technological systems. Victor a. kraSnyy, PhD. Associate professor at saint-Petersburg mining university. specializes in the field of technological methods of increasing wear resistance of machinery parts.

Growth of Scenedesmus obliquus under artificial flue gas with a high sulphur concentration neutralized with oil shale ash

Oil shale is the main energy resource in Estonia, which generates large amounts of CO2 and waste oil shale ash. Flue gas from oil shale combustion can also contain large amounts of SO2. Microalgae can be used for biological sequestration of carbon from flue gas. In this research, green algae Scenedesmus obliquus were grown with 14% CO2 in 1 L bioreactors. Sulphuric acid was added with a concentration of 500 ppm and 1000 ppm in order to imitate the dissolution of sulphur dioxide from flue gas into the growth medium. Oil shale ash was used to neutralize SO2. Biomass measurements of S. obliquus, carried out every 24 hours for 7 days, were used as a proxy for carbon fixation. The biomass yields of the untreated control and of the treatments were similar (maximum yield 2.9, 3.1, and 3.9 g L for the control, 500 ppm, and 1000 ppm treatment, respectively), suggesting that neither the sulphur nor the ash had an inhibitory effect on algal growth. In fact, the biomass yield was slightly higher in the treatments, which implies that minerals contained in waste ash could be utilized by algae. The calculated CO2 fixation rate was 0.45 g L d for the control, and 0.62 and 0.83 g L d for 500 ppm and 1000 ppm treatment, respectively. Therefore, microalgae can be used for carbon sequestration from flue gas. Further research should be done in order to optimize the growth conditions and maximize carbon fixation.

Mathematical Modelling of Cutting Process System

The mathematical modelling of the process system allows carrying out research into the selection and optimisation of machining conditions. The conceptualization of the operator that represents the dynamic characteristics of the cutting and friction process is an important issue in the development of the mathematical formulation of the interaction between subsystems in the cutting process. Currently, different approaches exist to the description of cutting and friction processes with the use of dynamic and quasi-static concepts, which results in the different studies using the machining process system models that are essentially distinct from each other. The subject of this paper is the method of dynamic process approximation, which allows analysing the behaviour of the machining process system in the process of chip formation at a sufficient level of accuracy.