Reduction in difficulties of phytomass combustion by co-combustion of wood biomass

Nowadays, the most used biofuel in Slovak republic is log wood. Alternatively, there are also biofuels based on vegetal biomass (phytomass) like wheat straw or grass. The advantage of these biofuels is lower cost price because they are usually considered as waste product. The major disadvantage of these vegetal biofuels is their problematic combustion. It is mainly due to the low ash melting temperature because of chemical composition of ash from phytomass. The low ash melting temperature causes slagging and sintering, which reduce the efficiency of the combustion process. This disadvantage causes very difficult and problematic combustion of phytomass. The article deals the way of trouble reduction during combustion of pellets made from phytomass (specific hay) through the wood pellet co-combustion in a standard automatic boiler for combustion of wood pellets. During the experiments, the mixing ratio of hay pellets and wood pellets is varied and subsequently, there is determined its impact on the combustion process, namely on heat output of the boiler, and there is also evaluated the effect of the mixing ratio on the production of carbon monoxide (CO), nitrogen oxides (NOx), sulphur dioxide (SO2), organic hydrocarbons (OGC) and particulate matters (PM10, PM2.5)

Modelovanie tvorby emisií malého zdroja tepla na spaľovanie uhlia

The aim of the work is to develop a method of simple characterization of solid fuels combustion in fixed bed, which would be useful for CFD modelling. In this work, the measurements were performed in a test rig, where a combustion front propagates against the airflow. Concentrations of flue gas species were registered at the exit of a fixed bed reactor and the temperature of burning coal was measured in selected points of the reactor as functions of time.Cieľom práce je vyvinuť metódu charakterizujúcu spaľovanie tuhého paliva na rošte, ktorá môže byť použitá pre matematické modelovanie. Práca pozostáva zo štyroch úloh: experimentálne merania zamerané na spaľovanie uhlia v reaktore s pevným roštom, spracovanie nameraných hodnôt do formy funkcií, matematické modelovanie v CFD a verifikácia modelu pomocou meraní vykonaných na kotle o výkone 25kW

PRODUCTION OF EMISSIONS DURING COMBUSTION OF DENDROMASS WITH DIFFERENT TYPES OF ADDITIVES

Dendromass remains the largest biomass energy source today. Dendromass has a lot of advantages in comparison with fossil fuels. One important benefit is reduced SO2 and NOx formation through a decrease in fuel bound sulfur and nitrogen respectively. One of applications of dendromass are wood pellets. Using of additives can affect some properties of wood pellets include combustion and production of emissions. In this work were produced wood pellets with additives (kaolin, talc, lime, limestone, dolomite) in 2 % amount in comparison with pellets which are free of additive (reference sample). The effect of various additives to formation of emissions was observed. Experimental measurements have been performed in domestic boiler for combustion of wood pellets with rated power 18 kW. During the measurements were recorded concentrations of following emissions: CO, SO2, NOx, OGC and particulate matters (PM) in the flue gas. The lowest concentrations of CO were recorded in the sample with 2% of kaolin in comparison with reference sample. The highest concentrations of carbon monoxide have been reported in sample with addition of lime. The results of SO2, NOx and OGC production indicate negligible difference, when comparing the reference sample to samples with additives. The highest amount of particulate matter was observed in measurements of lime and limestone. The sample with dolomite has lower concentration of total particulate matter in comparison to reference sample. The results of measurements indicate that the type of additive has a considerable effect on the combustion process and formation of emissions

The increase of silver grass ash melting temperature using additives

Some types of biomass have a high content of alkali oxides and salts and, thanks to it they feature a low ash melting temperature which may result in various combustion problems. Slag and sintered particles that are formed prevent the fuel from being supplied, restrict the access of combustion air, heat transfer in the heat exchanger and can cause corrosions. One possibility of increasing the ash melting temperature is to add additives. Some additives can change chemical composition of fuel ash, thus changing also the ash melting temperature. The paper deals with the adding of 2 % additives - kaolin, talc, lime, limestone, dolomite, bentonite to silver grass. The tested additives increased the ash content but they also changed its chemical composition, which resulted in the increase of the ash melting temperature. Best positive results were achieved with kaolin and lime which increased the ash melting temperature by approx 300 degrees C.Web of Science5126525

Optimization principle of operating parameters of heat exchanger by using CFD simulation

Design of effective heat transfer devices and minimizing costs are desired sections in industry and they are important for both engineers and users due to the wide-scale use of heat exchangers. Traditional approach to design is based on iterative process in which is gradually changed design parameters, until a satisfactory solution is achieved. The design process of the heat exchanger is very dependent on the experience of the engineer, thereby the use of computational software is a major advantage in view of time. Determination of operating parameters of the heat exchanger and the subsequent estimation of operating costs have a major impact on the expected profitability of the device. There are on the one hand the material and production costs, which are immediately reflected in the cost of device. But on the other hand, there are somewhat hidden costs in view of economic operation of the heat exchanger. The economic balance of operation significantly affects the technical solution and accompanies the design of the heat exchanger since its inception. Therefore, there is important not underestimate the choice of operating parameters. The article describes an optimization procedure for choice of cost-effective operational parameters for a simple double pipe heat exchanger by using CFD software and the subsequent proposal to modify its design for more economical operation

Specifics of phytomass combustion in small experimental device

A wood pellet combustion carries out with high efficiency and comfort in modern pellet boilers. These facts help to increase the amount of installed pellet boilers in households. The combustion process quality depends besides the combustion conditions also on the fuel quality. The wood pellets, which don`t contain the bark and branches represent the highest quality. Because of growing pellet demand, an herbal biomass (phytomass), which is usually an agricultural by-product becomes economically attractive for pellet production. Although the phytomass has the net calorific value relatively slightly lower than the wood biomass, it is often significantly worse in view of the combustion process and an emission production. The combustion of phytomass pellets causes various difficulties in small heat sources, mainly due to a sintering of fuel residues. We want to avoid the ash sintering by a lowering of temperature in the combustion chamber below the ash sintering temperature of phytomass via the modification of a burner design. For research of the phytomass combustion process in the small boilers is constructed the experimental combustion device. There will investigate the impact of cooling intensity of the combustion chamber on the combustion process and emissions. Arising specific requirements from the measurement will be the basis for the design of the pellet burner and for the setting of operating parameters to the trouble-free phytomass combustion was guaranteed

Specifics of phytomass combustion in small experimental device

A wood pellet combustion carries out with high efficiency and comfort in modern pellet boilers. These facts help to increase the amount of installed pellet boilers in households. The combustion process quality depends besides the combustion conditions also on the fuel quality. The wood pellets, which don`t contain the bark and branches represent the highest quality. Because of growing pellet demand, an herbal biomass (phytomass), which is usually an agricultural by-product becomes economically attractive for pellet production. Although the phytomass has the net calorific value relatively slightly lower than the wood biomass, it is often significantly worse in view of the combustion process and an emission production. The combustion of phytomass pellets causes various difficulties in small heat sources, mainly due to a sintering of fuel residues. We want to avoid the ash sintering by a lowering of temperature in the combustion chamber below the ash sintering temperature of phytomass via the modification of a burner design. For research of the phytomass combustion process in the small boilers is constructed the experimental combustion device. There will investigate the impact of cooling intensity of the combustion chamber on the combustion process and emissions. Arising specific requirements from the measurement will be the basis for the design of the pellet burner and for the setting of operating parameters to the trouble-free phytomass combustion was guaranteed

The impact of the weather conditions on the cooling performance of the heat pump driven by an internal natural gas combustion engine

Market with sources of heat and cold offers unlimited choice of different power these devices, design technology, efficiency and price categories. New progressive technologies are constantly discovering, about which is still little information, which include heat pumps powered by a combustion engine running on natural gas. A few pieces of these installations are in Slovakia, but no studies about their work and effectiveness under real conditions. This article deals with experimental measurements of gas heat pump efficiency in cooling mode. Since the gas heat pump works only in system air – water, air is the primary low – energy source, it is necessary to monitor the impact of the climate conditions for the gas heat pump performance

Influence of Biomass Combustion Method on Properties of Solid Fuel Residues

The correct course of the combustion process has a great influence on several output parameters. In addition to the impact on the performance and efficiency of the device, the impact on the formation and properties of gaseous emissions and solid residue is particularly noticeable. The solid combustion residue, in particular in the form of ash, remains trapped as the final product after combustion in the incinerator or may be released to the outside environment. Improperly, combustion can form two negative extremes. The first extreme is the formation of too fine dust particles of ash and solid pollutants escaping into the air as dangerous emission substances for human and other organism’s health. The second is the failure to burn larger pieces of fuel or sinter them into clumps, which can subsequently damage the combustion device or reduce the efficiency of combustion. This article aims to examine the various factors influencing the impact of combustion in different types of combustion plants on the properties of the resulting solid fuel residues and further possibilities of their use and effects on the environment

Designing the solar collector position with the Arduino electronic platform

The article deals with the utilizing of solar energy by the means of concentric trough collector based on own design. It focuses on achieving optimal position of the trough with respect to incident radiation during its operation. Due to the collector virtual sun tracking system, which was proved to be ineffective and could not achieve the desired results, the optimum position had to be maintained by manual control of rotation. The measurement of the angle of rotation of the concentric trough is realized using the ARDUINO electronic platform, for which the program was created in the software ARDUINO (IDE) 1.8.4