The Impact of Fuel Type on the Output Parameters of a New Biofuel Burner

Recent Advances in Application of Polyoxometalates in Lignocellulose Pretreatment and Transformation

Lignocellulose, composed of cellulose, hemicellulose, and lignin, holds immense promise as a renewable resource for the production of sustainable chemicals and fuels. Unlocking the full potential of lignocellulose requires efficient pretreatment strategies. In this comprehensive review, efforts were taken to survey the latest developments in polyoxometalates (POMs)-assisted pretreatment and conversion of lignocellulosic biomass. An outstanding finding highlighted in this review is that the deformation of the cellulose structure from I to II accompanied by the removal of xylan/lignin through the synergistic effect of ionic liquids (ILs) and POMs resulted in a significant increase in glucose yield and improved cellulose digestibility. Furthermore, successful integration of POMs with deep eutectic solvents (DES) or γ-valerolactone/water (GVL/water) systems has demonstrated efficient lignin removal, opening avenues for advanced biomass utilization. This review not only presents the key findings and novel approaches in POMs-based pretreatment but also addresses the current challenges and prospects for large-scale industrial implementation. By offering a comprehensive assessment of the progress in this field, this review serves as a valuable resource for researchers and industry professionals aiming to harness the potential of lignocellulosic biomass for sustainable chemical and fuel production.

A Comparative Analysis of Emissions from a Compression–Ignition Engine Powered by Diesel, Rapeseed Biodiesel, and Biodiesel from Chlorella protothecoides Biomass Cultured under Different Conditions

The priority faced by energy systems in road transport is to develop and implement clean technologies. These actions are expected to reduce emissions and slow down climate changes. An alternative in this case may be the use of biodiesel produced from microalgae. However, its production and use need to be justified economically and technologically. The main objective of this study was to determine the emissions from an engine powered by biodiesel produced from the bio-oil of Chlorella protothecoides cultured with different methods, i.e., using a pure chemical medium (BD-ABM) and a medium based on the effluents from an anaerobic reactor (BD-AAR). The results obtained were compared to the emissions from engines powered by conventional biodiesel from rapeseed oil (BD-R) and diesel from crude oil (D-CO). The use of effluents as a medium in Chlorella protothecoides culture had no significant effect on the properties of bio-oil nor the composition of FAME. In both cases, octadecatrienoic acid proved to be the major FAME (50% wt/wt), followed by oleic acid (ca. 22%) and octadecadienoic acid (over 15%). The effluents from UASB were found to significantly reduce the biomass growth rate and lipid content of the biomass. The CO2 emissions were comparable for all fuels tested and increased linearly along with an increasing engine load. The use of microalgae biodiesel resulted in a significantly lower CO emission compared to the rapeseed biofuel and contributed to lower NOx emission. Regardless of engine load tested, the HC emission was the highest in the engine powered by diesel. At low engine loads, it was significantly lower when the engine was powered by microalgae biodiesel than by rapeseed biodiesel.

Low Emissions Resulting from Combustion of Forest Biomass in a Small Scale Heating Device

The paper concerns the analysis of harmful emissions during the combustion process in households. The subject of the analysis is a low emission heating device with an output of 50 kW for burning biomass of forest origin (low-quality hardwoods or softwoods). The proposed boiler is automatically fed from the connected container by means of a screw conveyor. In this way, the optimum amount of fuel is supplied for maximum heat output (adjustment of the ratio of primary air to fuel). The proposed biomass heating system is equipped with a primary and secondary air supply system and exhaust gas sensors. This ensures optimal regulation of the air mixture and efficient and clean combustion. Proper control of the combustion process, control of the air supply by means of a lambda sensor and power control of the system ensure a low-emission combustion process. The system precisely adjusts to the heat demand. This results in highly efficient heating technology with low operating costs. In the presented work, the emission of exhaust gases from the proposed heating device during the combustion of woodchips and beech–oak pellets were measured. It is demonstrated that the proposed design of the boiler equipped with intelligent control significantly reduces emissions when the biomass solid fuels are used, e.g., CO emissions from beech and oak chips and pellets in the low-emission boiler—18 extract pipes shows the value <100 ppm, which is even lower than when gas is burned in the other boilers; on the other hand, the pine chips show even higher emission when burned in the low-emission burner. Consequently, the choice of biomass source and form of the fuel play some role in the emissions observed.

Perspectives for Mitigation of CO2 Emission due to Development of Electromobility in Several Countries

The creep trend method is used for the analysis of the development of electric car production in three regions: The United States, the European Union and Japan. Based on vehicle registration and population growth data for each year the creep trend method using historical data for the years 2007–2017 is applied for forecasting development up to 2030. Moreover, the original method for calculating the primary energy factor (PEF) was applied to the analysis of power engineering systems in the regions investigated. The assessment of the effects of electromobility development on air quality has been performed, reduction values for pollutant and greenhouse gas emissions have been determined, which was the main objective of this manuscript. Mitigation of air pollutant emissions, i.e., carbon dioxide (CO2), carbon monoxide (CO) and nitrogen oxides (NOx) was estimated and compared to the eventual expected increase of emissions from power plants due to an increase of the demand for electricity. It can be concluded that electricity powered cars along with appropriate choices of energetic resources as well as electricity distribution management will play the important role to achieve the sustainable energy economy. Based on the emission reduction projections resulting from the projected increase in the number of electric cars, (corrected) emissions will be avoided in 2030 in the amount of over 14,908,000 thousand tonnes CO2 in European Union, 3,786,000 thousand tonnes CO2 in United States and 111,683 thousand tonnes CO2 in Japan.

Comparison of Combustion Models for Lifted Hydrogen Flames within RANS Framework

Within the framework of a Reynolds averaged numerical simulation (RANS) methodology for modeling turbulence, a comparative numerical study of turbulent lifted H2/N2 flames is presented. Three different turbulent combustion models, namely, the eddy dissipation model (EDM), the eddy dissipation concept (EDC), and the composition probability density function (PDF) transport model, are considered in the analysis. A wide range of global and detailed combustion reaction mechanisms are investigated. As turbulence model, the Standard k-ε model is used, which delivered a comparatively good accuracy within an initial validation study, performed for a non-reacting H2/N2 jet. The predictions for the lifted H2/N2 flame are compared with the published measurements of other authors, and the relative performance of the turbulent combustion models and combustion reaction mechanisms are assessed. The flame lift-off height is taken as the measure of prediction quality. The results show that the latter depends remarkably on the reaction mechanism and the turbulent combustion model applied. It is observed that a substantially better prediction quality for the whole range of experimentally observed lift-off heights is provided by the PDF model, when applied in combination with a detailed reaction mechanism dedicated for hydrogen combustion.

Modeling of Biofuel’s Emissivity for Fuel Choice Management

The depletion of conventional energy sources, including crude oil, is one of the cause of the search for alternative carriers and fuels in order to prevent an energy crisis. Due to the progressing climate change, each new solution must comply with the principles of sustainable development. Dynamic development in the transport sector and, as a consequence, the increase in the number of vehicles on the roads negatively affect the atmosphere and the environment, which is why the share of biofuels, which are used to minimize this negative impact, is steadily increasing. This paper analyzes the emissivity (emission capability) of biofuels such as fatty acid methyl esters (FAME), ethanol, dimethyl ether and butanol and compares them with conventional fuels. A computer simulation was used, based on the real parameters of vehicles and fuels. The test procedure was carried out in accordance with the appropriate New European Driving Cycle (NEDC) approval test for such cars. In addition, a life cycle assessment (LCA) for the fuels and vehicles in question was carried out using the SimaPro package. Based on the results obtained from the z computer simulation, it was found that diesel fuel showed lower emissivity than petrol and its alternatives. However, FAME fuel provided more carbon dioxide than conventional diesel. As far as petrol is concerned, it was less emissive than dimethyl ether. Ethanol and butanol reduced emissions by 7% and 15%, respectively. After taking into account CO2 emissions generated in the production process, both FAME and butanol were not very favorable in the context of other fuels. The results might be used for appropriate fuel use management.

Gas Turbine Cycle with External Combustion Chamber for Prosumer and Distributed Energy Systems

The use of various biofuels, usually of relatively small Lower Heating Value (LHV), affects the gas turbine efficiency. The present paper shows that applying the proposed air by-pass system of the combustor at the turbine exit causes tan increase of efficiency of the turbine cycle increased by a few points. This solution appears very promising also in combined gas/steam turbine power plants. The comparison of a turbine set operating according to an open cycle with partial bypassing of external combustion chamber at the turbine exit (a new solution) and, for comparison, a turbine set operating according to an open cycle with a regenerator. The calculations were carried out for different fuels: gas from biomass gasification (LHV = 4.4 MJ/kg), biogas (LHV = 17.5 MJ/kg) and methane (LHV = 50 MJ/kg). It is demonstrated that analyzed solution enables construction of several kW power microturbines that might be used on a local scale. Such turbines, operated by prosumer’s type of organizations may change the efficiency of electricity generation on a country-wide scale evidently contributing to the sustainability of power generation, as well as the economy as a whole.

Influence of Different Biofuels on the Efficiency of Gas Turbine Cycles for Prosumer and Distributed Energy Power Plants

The efficiency of a gas turbine can be affected by the use of different biofuels usually with a relatively Lower Heating Value (LHV). The paper evaluates the impact of calorific value of fuel on turbine performance and analyzes the possibilities of optimizing turbine construction from the point of view of maximum efficiency for a particular fuel. The several variants of design of small power microturbines dedicated to various biofuels are analyzed. The calculations were carried out for: gas from biomass gasification (LHV = 4.4 MJ/kg), biogas (LHV = 17.5 MJ/kg) and methane (LHV = 50 MJ/kg). It is demonstrated that analyzed solution enables construction of several kW power microturbines that might be used on a local scale. Careful design of such devices allows for achieving high efficiency with appropriate choice of the turbine construction for specific fuel locally available. Such individually created generation systems might be applied in distributed generation systems assuring environmental profits.

Thermodynamic Fundamentals for Fuel Production Management

An increase of needs for replacement of fossil fuels, and for mitigation of Carbon Dioxide emissions generated from fossil fuels inspires the search for new fuels based on renewable biological resources. It would be convenient if the biological component of the fuel required as little as possible conversion operations in the production. The obvious response is an attempt to use unconverted, neat plant oils as a fuel for Diesel engines. The present paper is devoted to the experimental studies of the combustion process of neat rapeseed oil, and its mixtures with gasoline and ethanol as additional components of the mixtures. The investigation of combustion was carried out in a fixed volume combustion chamber equipped with a Common Rail injection system. It is shown that the instant of ignition, as well as time-dependence of heat emanation, are strongly dependent upon mixture composition. The results enable the design of mixture compositions that could serve as commercial fuel for Diesel engines. Such fuels are expected to fulfill the requirements for the sustainability of road transport.

The Effects of Pressure and Temperature on the Process of Auto-Ignition and Combustion of Rape Oil and Its Mixtures

The effects of initial pressure and temperature in a constant volume test chamber with a common rail injection system on the processes of self-ignition and combustion of rapeseed oil and various blends of rapeseed oil with diesel oil are explored. Based on the obtained pressure waveforms the amount of emitted heat was determined, and the tested fuels were compared. The variations of a number of physicochemical characteristics that occur during the combustion processes were evaluated for several mixtures of fuel components. It was found that in the case of blends of rapeseed oil with diesel oil, the best results were obtained for a mixture containing 70 weight percent of diesel oil and 30% of rapeseed oil.