Papers by Eriks Kronbergs
Biomass conversion for obtaining energy and fertilizers
Vide. Tehnoloģija. Resursi, Jun 26, 2006
Substitution of fossil feedstock for energy and raw materials by biomass is important measure for... more Substitution of fossil feedstock for energy and raw materials by biomass is important measure for GHG emission mitigation. Development of energy crop production and agricultural residue utilisation for energy are important goals of the rural policy. As chemical fertiliser production and usage corresponds to the consumption of oil fuel, biomass usage directly for energy production or as fertiliser are activities with equal importance. The main rural resources for biomass eco-technologies in Latvia are cereal straw residues, energy crops, emergent vegetation and peat from wetlands and sediments from lakes. Wide range of biomass properties cause necessity of appropriate mechanization equipment for biomass conditioning accordingly collection, conversion and usage technologies. The ecosystem approach means taking into account the interrelationships among land, air water and all living organisms including humans for mechanization equipment design of biomass technologies. Complex mechanisation of biomass technologies is based on implementation of ecosystem approach and investigation of properties of biomass in conditioning processes. For solid biofuel production densification properties of chopped stalk materials with different additives (peat, rapeseed cake) had been determined.
Compaction Characteristics of Common Reeds and Mechanism for Solid Biofuel Production
European Biomass Conference and Exhibition Proceedings, 2011
The paper present experimental investigation results of common reeds (Phragmites Australis) parti... more The paper present experimental investigation results of common reeds (Phragmites Australis) particle compacting in closed die. Common reeds are important natural biomass resource in Latvia. Compacting of biomass is complicated process for solid biofuel production and there are many factors influencing to this process. Maximum pressure 212 MPa had been achieved in compacting. For compacting process evaluation has been determined pressing energy and density of briquettes. Density of briquettes obtained during compacting was determined 904 – 1057 kg m-3 with uncertainty ±10 kg m-3. The minimum of density 904 kg m-3 have briquettes with particle size 12 – 13 mm, but maximum density 1051 – 1057 kg m-3 two particle sizes < 0.5 mm and 32 – 33 mm briquettes. Force – displacement characteristics of compacting are nonlinear curves with two quasilinear parts. Similar nonlinear characteristic rhomboid mechanism (Patent LV 14201) calculation had been realized by MathCAD software.
Plant biomass conditioning for energy production
Vide. Tehnoloģija. Resursi, Aug 5, 2015
The paper present experimental investigation results of common reeds (Phragmites australis) parti... more The paper present experimental investigation results of common reeds (Phragmites australis) particle compacting in closed die. Common reeds are important natural biomass resource in Latvia. Compacting of biomass is very complicated process for solid biofuel production and there are many factors influencing to this process. The quality parameters of compacted biomass are described by European countries standards for solid biofuel. Density is the most important quality parameter of biomass compacting. The paper present results of common reeds particles compacting mechanism in closed die. Maximum pressure 212 MPa had been achieved in compacting. For compacting process evaluation has been determined pressing energy and density of briquettes. The minimum of density 0.87 g cm-3 have briquettes with particle size 12-13 mm, but maximum density 1.03-1.04 g cm-3 two particle sizes < 0.5 mm and 32-33 mm briquettes. Maximum value of energy consumption for compacting (~172 kJ kg-1) has been obtained for reed particle size 32-33 mm, minimum value (~53 kJ kg-1) for particle size less than 0.5 mm.
22nd International Scientific Conference Engineering for Rural Development Proceedings
The parallel transfer mechanism (patent LV 15506B) consists of links in form of two parallelogram... more The parallel transfer mechanism (patent LV 15506B) consists of links in form of two parallelograms with one common horizontal link and parallel to it opposite links of equal length, and the links of side edges of the parallelograms the lengths of which are equal in pairs, respectively. The common link of the parallelograms is formed as a guide for a slider to which two links are connected corresponding to the lengths of the side edge links of the parallelograms. The other ends of these elements are connected to the side edge links forming a rhomboid contour. The links of this planar linkage are connected by pin joints. For cyclic operation of the parallel transfer mechanism the hydraulic actuator is connected to the slider and attached to the common link. If the lower parallelogram link is the ground link, the output link will be the upper link, which parallel transfer movement will be ensured. The purpose of the work is kinematic analysis of this innovative mechanism. The side memb...
Organic matter (sapropel) used for soil fertility and heat
Raziba (Latvia), 1997
[Organic matter (sapropel) used for soil fertility and heat]. [Latvian]
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
The main steps of rural policy to the development of renewable energy resources are energy crop p... more The main steps of rural policy to the development of renewable energy resources are energy crop production. Latvia can provide for the use of approximately 0.36 million ha of the unused now agricultural land for herbaceous energy crop growing. More than 230 million tones of peat are available for solid biofuel production. Peat is recomended as additive because it improves density and burning properties of herbaceous material solid biofuel. Herbaceous stalk material can be harvested in winter season with humidity less than 15% and used for compacting without drying. The aim of experimental investigation is to determine conditioning methods for solid biofuel production with minimum energy consumption. Common reed stalk material is used for experiments, because it experimentally stated ultimate tensile strength is 256 ± 27 N mm-2. This value testifies that common reeds are twice strongest material than cereal crop stalk materials and conditioning mechanization equipment of common reeds...
ENGINEERING FOR RURAL DEVELOPMENT Jelgava, 28.-29.05.2009. 207 CUTTING PROPERTIES OF COMMON REED BIOMASS
Abstract. The EU Common agricultural policy stimulates farmers to grow more energy crops, includi... more Abstract. The EU Common agricultural policy stimulates farmers to grow more energy crops, including short rotation coppice and other perennial crops. There are other resources of bioenergy as agricultural residue and peat. Peat can be used as an additive for manufacturing of solid biofuel, because it improves the density, durability of stalk material briquettes (pellets) and avoids corrosion of boilers. Naturally herbaceous biomass is a material of low density (20-60 kg m-3) and not favorable for transportation on long distances. Baling can increase the bulk density to 100-200 kg m-3. The main conditioning operation before biomass compacting is shredding. The shredder cutterbar has to be designed with friction energy losses decreased to minimum. According to this mainly stalk material cutting properties have to be investigated. Experimental investigation of common reed stalk conditioning properties as different cutting methods can characterize maximum of energy consumption in these ...
Abstract. The purpose of the work is to investigate mechanical durability of briquettes and pelle... more Abstract. The purpose of the work is to investigate mechanical durability of briquettes and pellets of energy crop biomass. Briquettes were produced from common reed (Phragmites Australis L.), reed canary grass (Phalaris arundinacea L.) and mixture of peat with common reeds and reed canary grass but pellets from reed canary grass and peat mixture. Briquettes and pellets mechanical durability test was realized according to the LVS EN 15210 standard. The durability is the measure of the resistance of compacted fuels to affection of shocks and abrasion as a consequence of handling and transportation processes. It is stated as percentage of remaining mass of biofuel after sieving. The requirement of standards (LVS EN 14961-1:2010) for mechanical durability of low quality briquettes is <90.0 % (minimum value to be stated) and high quality briquettes ≥95.0 %, but mechanical durability of low quality pellets is <95.0 % (minimum value to be stated) and high quality pellets ≥97.7 %. Th...
Abstract. The main conditioning operation before preparation of herbaceous biomass compositions f... more Abstract. The main conditioning operation before preparation of herbaceous biomass compositions for solid biofuel production is shredding and grinding. Naturally herbaceous biomass is a material of low density ≈ 60 kg·m -3 and not favorable for transportation on long distances. Grinding and compacting with normal pressure up to 0.17 MPa, the bulk density of common reed biomass increases up to 390 kg·m -3 . In this study, size reduction of common reeds (Phragmetis Australis) was carried out using a hammer mill Peruzzo Export 200 and material testing machine Zwick TC-FR2.5TN.D09. The hammer mill was equipped with eight different screens with mesh size within 1 and 20 mm. According to the standard DD CEN/TS 15103..2005 the bulk density of comminuted common reed material for each screen grinds was determined. For compacting pressure influence on the material bulk density Zwick TC-FR2.5TN.D09 was equipped with compression cell. Bulk density changes were determined for the pressure up to ...
Abstract. Latvia has a target in 2020 for renewable energy resources to be 40 % in gross final co... more Abstract. Latvia has a target in 2020 for renewable energy resources to be 40 % in gross final consumption of energy. Herbaceous energy crops would be as the main basis for solid biofuel production in agricultural ecosystem in future. According to it the reed canary grass stalk material properties have to be investigated for solid biofuel production. The main conditioning operation before compaction of herbaceous biomass compositions for solid biofuel production is shredding and milling. Naturally herbaceous biomass is a material of low density ≈ 60 kg·m -3 and not favorable for transportation on long distances. Shredding can increase the bulk density to 280 kg·m -3 . The reed canary grass stalk material shredding properties have to be investigated in order to find minimum of energy consumption for size reduction. The purpose of the work is to investigate the reed canary grass cutting energy consumption dependence on the bale shredder settings. For reed canary grass shredding a bale...
Abstract. This paper presents a mathematical model of vertical oscillations of a tractor aggregat... more Abstract. This paper presents a mathematical model of vertical oscillations of a tractor aggregate with an implement. A mathematical model of the tractor aggregate is derived to suit the control task of damping of oscillations. The dynamical model of wheels, coupled with the body, is representing the tractor with an implement. The wheels due to the compressibility of the tires are represented as spring-damper systems. The body of the tractor and implement are represented as a two beam system, connected with thse joint and springdamper system. In order to derive a dynamic model of the system, the necessary calculations are made. The Lagrange's equation of second kind is used to derive the equations of motion of the described system.
Durability of compacted energy crop biomass
The purpose of the work is to investigate mechanical durability of briquettes and pellets of ener... more The purpose of the work is to investigate mechanical durability of briquettes and pellets of energy crop biomass. Briquettes were produced from common reed ( Phragmites Australis L.), reed canary grass (Phalaris arundinacea L.) and mixture of peat with common reeds and reed canary grass but pellets from reed canary grass and peat mixture. Briquettes and pellets mechanical durability test was realized according to the LVS EN 15210 standard. The durability is the measure of the resistance of compacted fuels to affection of shocks and abrasion as a consequence of handling and transportation processes. It is stated as percentage of remaining mass of biofuel after sieving. The requirement of standards (LVS EN 14961-1:2010) for mechanical durability of low quality briquettes is <90.0 % (minimum value to be stated) and high quality briquettes �95.0 %, but mechanical durability of low quality pellets is <95.0 % (minimum value to be stated) and high quality pellets �97.7 %. The results...
Design of sapropel extraction
Stalk material cutting energy
Physical model of tractor implement
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
The main task of this investigation is evaluation of patented (LV 14604 B) biomass briquetting me... more The main task of this investigation is evaluation of patented (LV 14604 B) biomass briquetting mechanism. Theoretical relationship between necessary drive force and resistance force during pressing in die was determined. Briquettes from grinded common reed (Phragmites Australis) or common reed-peat mixture were produced with designed experimental briquetting press. Density of common reed briquettes depending on the size of particles was stated. Density of briquettes obtained during compacting was from 826.3±16.4 to 934.5±35.1 kg m-3. The minimum of density 826.3±16.4 kg m-3 had briquettes with particles from 6 mm grinding screen, but maximum density 934.5±35.1 kg m-3 had briquettes, when particles from 1.5 mm grinding screen had been used. Compositions of reed particles with peat allow obtaining briquettes density > 1000 kg m-3 if peat proportion in mixture is 30%. Results of theoretical and experimental investigation show that the designed pressing mechanism can be recommended f...
ENGINEERING FOR RURAL DEVELOPMENT Jelgava, 29.-30.05.2008. 260 DENSITY OF COMPACTED HERBACEOUS STALK MATERIALS
Abstract. The 2003 reform of the EU Common agricultural policy introduced a special “energy crop ... more Abstract. The 2003 reform of the EU Common agricultural policy introduced a special “energy crop payment” under which a premium of €45 per hectare is available for the production of energy crops. There is possibility in Latvia to provide for the use of approximately 0.36 million ha of the unused now agricultural land for energy crop growing. There are others resources of bioenergy in Latvia as agricultural residues and peat. More than 230 million tones of peat are available for solid biofuel production. Peat can be used as additive for manufacturing of briquettes, because it improves density of herbaceous material briquettes. European countries have standards (ŌNORM 7135, SS 18 71 20 and DIN 51731) concerned with wood pellet and briquette properties. Compacting is necessary operation for solid biofuel production from herbaceous stalk materials because the density of dry herbaceous stalk materials (straw, reeds) is too low (20 – 60 kg m-3) for transportation on long distances. For de...
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Papers by Eriks Kronbergs