Low-power Boilers Research Articles

Combustion of liquid hydrocarbon fuels sprayed into gas generation chamber with superheated steam as low emission technology for energy production

Experimental and numerical studies were conducted to scientifically validate the Steam Injection Method with Gas Generation chamber (SIMGG) as a low-emission combustion technology for energy production in low and medium power boilers using different types of fuels. For the first time, a fully functional prototype of a burner implementing SIMGG was tested under the conditions of a standard low-power boiler installation, and combustion characteristics of fuels with various physical properties (diesel fuel and a mixture of used automotive oils) were obtained under different operating parameters. The results of the studies show that using SIMGG reduces carbon monoxide (CO) and nitrogen oxides (NOx) emissions by up to half or more under closed-combustion conditions for various fuels. The lowest total emissions of CO and NOx are achieved at an air excess coefficient of 1.2 and a steam-to-fuel ratio of greater than 0.66.

Efficient Combustion of the Fixed Coal Layer in an Advanced Combustion Chamber Design for Low-Power Boilers

Efficient Combustion of the Fixed Coal Layer in an Advanced Combustion Chamber Design for Low-Power Boilers

The Impact of Additives on Gaseous Pollutants from the Combustion of Various Solid Fuels

This article compares the emission of gaseous pollutants such as CO2, CO, NO, SO2, and HCl emissions from the combustion of the selected most popular solid fuels in a low-power boiler. The process was carried out under controlled conditions on a laboratory stand equipped with a Moderator Unica Vento Eko 25 kW boiler. Solid fuels were selected for comparison, such as hard coal with granulation above 60 mm, hard coal with a granulation of 25–80 mm, hard coal with a granulation of 8–25 mm, wood pellets, and mixed firewood. The experiment was carried out in two stages. In stage 1, previously selected solid fuels were combusted under controlled repeatable conditions, while simultaneously measuring gaseous components in the exhaust gases in real time. On the other hand, the second stage involves the combustion of the same fuels under the same conditions with combustion additives that modify the combustion process in terms of reducing the emission of pollutants. At the same time, in the second stage, gaseous components in the exhaust gas were also measured in real time. The experiments carried out have shown that, in addition to the additive, a testing system should be used to assess the profitability and improve the efficiency of energy production and distribution after using a given additive for fuel combustion. Implementation of the use of solid fuel activators on a common scale should also entail research on the emission of dioxins and furans, which may be emitted in increased amounts under the influence of some components contained in combustion modifiers.

CFD MODELING OF THE COMBUSTION OF UKRAINIAN AND BIOMASS IN A FLARE BOILER UNIT TPP-210a

To increase the amount of energy produced with the bioresources use is the most important step in environmentally friendly electricity production. An analysis of the computer modeling results of pellet and biomass burning processes in the furnace chamber of the TPP-210a steam boiler was carried out. The scientific novelty of the work consists of determining the possibility and perspective of using non-design types of fuel, such as gas coal of domestic production and solid biomass (instead of anthracite), as a raw material base of existing boiler units. On the basis of this analysis, it was determined that the model allows to quite accurately assess the aerodynamic structure of the flow in the burners and the boiler furnace. Such a precise assessment is possible if the thermophysical properties of the burning fuel are accurately specified. The average integral temperature of the combustion products in the fuel during the gas coal burning is higher than while burning other fuels in the form of pellets from the sunflower husk and from biomass of spring wheat and winter wheat. The biomass used in the modeling has a similar chemical composition; therefore, the temperature distributions in the case of their burning are also similar. Subsequently, the results of the research can be used to increase the efficiency of the combustion process when burning biofuel and to modernize fuel-burning systems of low-power boilers of industrial and municipal thermal engineering, the housing-and-utilities sector, etc.

INTEGRATION OF HEATING SYSTEM OPERATION

Ukraine has a huge asset in the form of existing district heating (DH) networks and demand for related services. DH is transforming the European energy sector, attracting efficient, local and renewable energy resources where this was not possible. However, due to the old material base of spare parts, insufficient level of investment and low level of management, Ukrainian DH systems are ineffective and do not meet the needs of consumers. The experience of European Union member states in central Europe shows that deep and sustained reforms can address the current challenges of the heating sector, including improving energy efficiency and economic competitiveness, strengthening environmental sustainability and enhancing energy security. The DH sector in Ukraine has not yet undergone the structural reform that other sectors of the economy have already gone through: over the past 30 years, the quality of services has decreased; subsidies have increased; the old material base is falling apart; The question arises whether it is worth continuing to support DH. As a result, Ukraine's DH sector is in dire straits, with financial, operational and technical problems compounding each other. Comprehensive and well-planned efforts must be made to create the conditions for exiting this state. Such structural reforms are essential to attracting the investment needed to improve the quality, efficiency and long-term potential of the district heating sector.
 The article examines the possibility of using modern technological solutions to modernize heat supply systems in order to improve their efficiency, which can lead to improved district heating services, transparency and financial stability.
 Keywords: energy resources, renewable energy sources, fossil fuels, automated heat and power plant, electricity, hot water, hot air, heating, private households, electric water heater, geothermal heat pump, wind power generator, low-power boiler house.

INTEGRATION OF THE OPERATION OF A HEAT AND POWER PLANT

The main motive for the accelerated development of renewable energy in Europe, the United States and many other countries is the desire of states for energy independence and environmental security. The impetus for the use of new technologies in the use of energy from non-traditional sources was two factors: the energy crisis of the early 70s and the increasing requirements for environmental protection. The experience gained by different countries in the use of heat pumps and wind power generators demonstrates the high possibilities of easily converting these types of energy into thermal energy and electricity, which can be successfully used to supply: electricity, hot water, hot air, heating in the premises of public and private households, and as well as providing various kinds of technological and domestic needs not only in different industries, but also at the enterprises of the agro-industrial complex of Ukraine. In this paper, the authors propose a developed and implemented improved automated heat and power plant for supplying: electricity, hot water, hot air and heating for private households. To solve the above problems, a scheme was developed for preheating the coolant through the use of: an electric water heater with a thermal power of 54 kW, a heat pump and a wind power generator with an electrical power of 50 kW, which produces electricity for the operation of all electrical equipment in private households and batteries of electricity and heat. The automation system allows you to control the installation without human intervention. The operation of this installation makes it possible to save organic fuel, which would be used to heat the coolant to the required temperature in a low-power boiler house.

Possibilities for Prediction And Evaluation of the Carbon Footprint in Furnace Fuel Oil Combustion in Medium- and Low-Power Boilers

Possibilities for Prediction And Evaluation of the Carbon Footprint in Furnace Fuel Oil Combustion in Medium- and Low-Power Boilers

Possibilities for Prediction And Evaluation of the Carbon Footprint in Furnace Fuel Oil Combustion in Medium- and Low-Power Boilers

Possibilities for Prediction And Evaluation of the Carbon Footprint in Furnace Fuel Oil Combustion in Medium- and Low-Power Boilers

DETERMINATION OF CONDENSABLE PARTICULATE MATTER RELEASED BY THE COMBUSTION OF SOLID FUELS IN LOW-POWER BOILERS

Despite significant emission control steps in recent decades, damage to air quality caused byparticulate matter with a diameter of 2.5 m or less is now a major concern on a global scale.Condensable particulate matters (CPM) due to their significant contribution to the totalconcentration of particulate matter and their small aerodynamic size (below 2.5 m) are now ofwidespread interest. CPMs produced in low-power solid fuel heating systems can be one of themain components of the total mass of fine particles present in the air we breathe. The operatingconditions of large power installations and small heating boilers differ significantly, therefore itis necessary to adapt the research methods adapted to industrial installations, to the low-powerboilers. In the tests, three fuels were combusted in two low-power boilers (18 kW boiler witha suction feeder and 5class 14 kW boiler with a screw feeder): bituminous coal, pine and sprucewood pellets and cereal straw pellets. An EPA 202 method was used to collect the CPM. Qualitativeand quantitative analyses of inorganic and organic CPM components were performed. Analysesof the inorganic part of the CPM included the determination of metals m.in Na, Ca, Fe, Mg, Al,K, and water-soluble ions, m.in SO42, Na+, K+ and Cl, while analyses of the organic part of theCPM comprised the determination of PAHs. Differences were observed in the amount of CPMgenerated depending on the fuel used and the type of low-power boiler used. CPM emissions arerelatively high and constitute a large part of total particulate matter, so the impact of CPM on theenvironment cannot be ignored and we should pay special attention to its research and control,especially from small solid fuel heating boilers.

Toxicity of carcinogenic pahs in boiler flue gases thermal capacity up to 1 Mw

THE PURPOSE. In accordance with the new requirements of domestic environmental legislation, technological principles of state regulation of the negative impact of energy enterprises on the environment have been introduced. The established principles of environmental protection activities provide for technological regulation of emissions based on the introduction of the best available technologies, as well as differentiation of state regulatory measures to ensure the environmental safety of thermal power facilities. Within the framework of the current environmental legislation, it is shown that it is necessary to determine emission standards for highly toxic substances that have carcinogenic properties. The main representatives of carcinogenic PAHs found in the flue gases of boilers of low power up to 1 MW are considered.METHODS. The research methods included the generalization of experimental data and thecalculated assessment of the content of carcinogenic emissions, including benz(a)pyrene in the flue gases of boilers using statistical data processing methods.RESULTS. The necessity of taking into account the contribution of the harmfulness of carcinogenic PAHs in the system of industrial environmental control at thermal power facilities during the operation of low-power boilers is determined.CONCLUSION. The results of the study can be used at energy enterprises to implement the requirements of the new environmental legislation in terms of technological regulation of carcinogenic emissions, including for the development of measures to improve environmental performance indicators.

Utilization of Ashes from Biomass Combustion

Biomass is one of the most important sources of renewable energy in the energy industry. It is assumed that by 2050 the global energy deposit could be covered in 33–50% of biomass combustion. As with conventional fuels, the combustion of biomass produces combustion by-products, such as fly ash. Therefore, along with the growing interest in the use of biomass as a source of energy, the production of ash as a combustion by-product increases every year. It is estimated that approximately 476 million tons of ashes per year can be produced from biomass combustion. For example, the calorific value of dry wood mass tends to be between 18.5 MJ × kg−1 and 19.5 MJ × kg−1, while the ash content resulting from thermal treatment of wood is from 0.4 to 3.9% of dry fuel mass. However, biomass ash is a waste that is particularly difficult to characterize due to the large variability of the chemical composition depending on the biomass and combustion technology. In addition, this waste is, on the one hand, a valuable fertilizer component, as it contains significant amounts of nutrients, e.g., calcium (Ca), potassium (K) and microelements, but on the other hand, it may contain toxic compounds harmful to the environment, including heavy metals and substances formed as a result of combustion, such as polycyclic aromatic hydrocarbons (PAHs) or volatile organic compounds (VOCs). PAHs and VOCs are formed mainly in the processes of incomplete combustion of coal and wood in low-power boilers, with unstable operating conditions. However, it is important to remember that before the fly ash is used in various industries (e.g., zeolite synthesis, recovery of rare earth metals or plastic production) as an additive to building materials or fertilizers for cultivation, a number of analyses are to be conducted so that the by-products of combustion could be used to allow the by-product of combustion to be used. It is important to conduct tests for the content of heavy metals, chlorides, sulphates, microelements and macroelements, grain and phase composition and organic compounds. If such ash is characterized by low pollution levels, it should be used in agriculture and reclamation of degraded land and not directed to landfills where it loses its valuable properties. The purpose of this review is to present the properties of ashes generated as a result of biomass combustion in Poland and the world, to discuss factors influencing changes in its composition and to present the possibilities of their reuse in the environment and in various branches of industry.

Waste Incineration and Heavy Metal Emission—Laboratory Tests

The main sources of environmental pollution with heavy (ecotoxic) metals include industry, including utility and municipal power engineering, but also waste incineration plants. Fuel shortages and their constantly growing prices raise concerns that energy will be commonly obtained from waste outside of installations intended for this purpose (i.e., outside waste incineration plants). The greatest concern stems from the risk of burning waste in low-power boilers—domestic boilers. Waste incineration plants and utility power plants are equipped with flue gas cleaning installations (FGD), but low-power boilers are not. The exhaust gases are directly introduced into the atmosphere, which results in the introduction into the air of, inter alia, toxic heavy metals. Therefore, it is necessary to conduct activities aimed at retaining ecotoxic metals in the solid–slag residue. The paper presents the results of laboratory tests of the emission capacity of Cd, Cu, Zn bound in various chemical forms—nitrates (V), chlorides and sulphates (VI). The tests were carried out at 1073 K, 1173 K and 1273 K. It was found that the emissivity of metals increased with increasing temperature. This is innovative as there are no reports of experiments with pure forms of metal salts. The advantage of this type of research is the lack of influence from other factors, apart from temperature, on metal emissions. To check the possibility of reducing metal emissions, additives (bauxite, dolomite, V2O5) immobilized in a solid residue were tested. The mechanism of action of each of the additives to limit the mobility of metals was different. The use of V2O5 for this purpose is new. The additives kept the metals solid in the residue, but their effect was different for each of the metals. The effectiveness of the tested additives was checked in the same temperature conditions, burning waste such as: rubber, sewage sludge and SRF fuel from waste. The effect of the additives depended on the type of waste, type of metal and the furnace temperature. If the additive effectively retained metals, then their amounts in the ashes were higher by several to several dozen percent in relation to the amount in the ashes remaining after waste incineration without additives. The results of the experiment with waste are open to research on the influence of other factors (except temperature) on the emissivity of Cd, Cu, Zn and the possibility of its reduction. The next step will be to verify the effects of laboratory tests in real conditions.

Assessment of phytotoxicity of ash and slag waste from low-capacity boiler houses and individual heating systems on the example of the town Shakhtersk, Sakhalin region

The relevance of the work is due to the study of the issue of disposal and possible use of ash and slag waste in small towns, in particular in the Far East, where the predominant types of heating are low-power boilers or individual heating systems. The simplest and clearest methods for assessing the impact of generated waste on the environment are bioindicative methods, in particular, the assessment of phytotoxicity. The analysis of the phytotoxic effect of ash and slag wastes of various origins and different periods of storage, as well as coal samples in the conditions of urban settlements, was carried town Shakhtersk, Sakhalin region, in relation to herbaceous plants of various systematic groups in the framework of a number of laboratory experiments. The phytotoxic effect of the considered samples was determined by comparing the parameters of the test function of the control and experimental seeds. The dependence of the magnitude of the phytotoxic effect on the shelf life and the type of origin of ash and slag waste is shown. The data obtained are the basis for carrying out additional experiments and studies, as well as determining the chemical composition of the samples under consideration.

Influence of the Use of Permanent Catalytic Systems on the Flue Gases Emission from Biomass Low-Power Boilers

The paper presents the research results on the use of permanent catalytic systems applied to the surface of a low-power boiler deflector. The tests were carried out on a standard 15 kW retort boiler. The boiler was powered by three types of biomass pellets (wood pellets, wheat straw pellets, and hemp expeller). In the research cycle, the influence of the catalysts on the emission of individual compounds, CO, NOX, particulate matter (PM), polycyclic aromatic hydrocarbons (PAH), and volatile organic compounds (VOC) and the influence on the temperature in the combustion chamber were examined. The tests used an exhaust gas analyzer, a dust meter, a two-channel aspirator, and a laboratory gas chromatograph stand with a flame ionization detector. Four catalysts (copper, manganese, titanium, and platinum) were prepared for the analysis. Each catalyst had three variants of the active substance concentration on the ceramic support surface: 17.5 g, 35 g, 52.5 g for CuO, TiO2, MnO2, and, respectively, 0.05 g, 0.1 g, and 0.15 g for platinum. Concerning the deflector surface, this concentration corresponded to 140, 280, and 420 g·m−2 for CuO, TiO2, and MnO2, and 0.4, 0.8, and 1.2 g·m−2 for platinum catalysts. All the catalysts used contributed to an increase in the combustion temperature and a reduction in pollutant emissions. The results presented in the paper will allow the implementation of the developed solutions in the industry producing low-power boilers and in already-existing heating installations. The factor that motivates the introduction of changes may be continuously tightening European emission regulations.

The impact of fuel delivery logistics on the cost of thermal energy on the example of biofuels boilers in Ukraine

One of the important directions for achieving the goals of sustainable development and decarbonization is to increase the share of biofuels, including in heat supply systems. In this case, an important factor in deciding on the use of biofuel boilers is the cost of fuel, which is affected by the delivery logistics. The authors determined the impact of logistics for different types of fuel for low-power boilers (0.5 and 1 MW, burning biofuels) on LCOH. The calculations take into account the existing rates of environmental tax. The paper considers the transportation of biofuels by road to small consumers over short distances (within a radius of several hundred kilometers). The study showed that the cost of delivery of pellets from producer to consumer can be up to 20% of their cost. It is established that the transportation of a ton of pellets per 1 km increases the cost of this ton by about 1.35 UAH, therefore, the logistical component in the final cost of pellets can be significant.

Analysis of the Effect of Catalytic Additives in the Agricultural Waste Combustion Process.

This paper presents the research results of the effect of using calcium oxide and potassium permanganate on the combustion of pellets from wheat bran and beet pulp. The measurements were performed in the technical laboratory of the Centre of Energy Utilization of Non-Traditional Energy Sources in Ostrava. The research examined the effect of the use of chemical substances on the amount of air pollutants from biomass thermal conversion in a low-power boiler and the process temperature. First, we performed technical and elementary analyses of agricultural waste. The raw material was then comminuted, mixed with a selected additive, pelletized, and finally burned in a low-power boiler. The additive was added in three proportions: 1:20, 1:10, and 1:6.67 (i.e., 15%) relative to the fuel weight. The combustion process efficiency was measured using a flue gas analyzer and three thermocouples attached to the data recorder. From the measurement results, we were able to determine the percentage reduction of pollutant emissions into the atmosphere (CO, NOx, and SO2) due to the use of additives. Because emission standards are becoming increasingly stringent and fuel and energy prices are rising, the results presented in this article may be useful to agri-food processing plants that want to manage these materials thermally.

Energy-Independent Heating System with Improved Energy Efficiency for Agricultural Premises

Introduction. The article is concerned with increasing the efficiency of energy-independent heat supply systems in agriculture through using a heat recovery unit with a thermomechanical energy converter. The most promising is a thermomechanical energy converter with a thermodynamic cycle of periodic action to drive a diaphragm pump. For heaters and boilers, the use of pulsating mode of the heat carrier has a double effect: it increases heat transfer and reduces the formation of deposits on the heat transfer surfaces. Materials and Methods. Using the thermodynamic method and the possibilities of impulse technologies, a thermodynamic cycle and a device of periodic action were proposed. In this device, three thermodynamic processes are sequentially implemented: isochoric heating and evaporation of the working substance, adiabatic performance of work, and isobaric condensation. Thermodynamic cycles are constructed for five known working substances (R11; R21; R113; R114; R123) on lgP-h thermodynamic state diagrams and their parameters at characteristic points are calculated. Results. There has been performed frequency matching of the thermal-mechanical converter with the hydraulic parameters of the heat source and heat-consuming unit. Such matching was based on the frequency responses. To describe the hydrodynamics of the heat supply system, a system of differential equations with constant coefficients was used, which was solved using the Laplace transformation. A rational frequency of oscillations of the heat carrier flow was determined within the range of 1.38–2.76 rad/s. Discussion and Conclusion. A scheme of a heat supply system with the independent connection of the heat-consuming unit to a heat source is proposed. On the example of a heat source with a power of 100 kW, graphical dependences of the heat source minimum pressures on the change in the consumption of a heat carrier and the active hydraulic resistance of the heat network are obtained. An algorithm for determining the power increment from the use of a heat exchanger with a thermomechanical converter is proposed. It has been determined that the efficiency of the heat recovery unit will be higher for low-power boilers.

New ecology safe waste-to-energy technology of liquid fuel combustion with superheated steam

The huge amounts of accumulated unclaimed liquid hydrocarbon waste (waste from oil production and oil refining, etc.) determine the prospects for their involvement in energy production. The Waste-to-Energy technology improves economic efficiency through low energy costs. Efficient use of waste for energy production requires the creation of new technologies with high energy efficiency and low emissions. The paper proposes and substantiates a promising new environmentally friendly Waste-to-Energy method of burning liquid fuel with injection of superheated steam (SIM) to the combustion zone. The authors have developed a new burner to combust liquid waste when producing energy (protected by patents of the Russian Federation), in which the fuel is atomized by a jet of superheated steam. This approach provides efficient fuel dispersion, the ability to burn a wide range of waste, high fuel combustion efficiency, long service life due to the absence of fuel injectors, and reduction of toxic combustion products due to steam. The large-scale introduction of new burners based on the SIM combustion technology requires reliable scientific data and pilot test results. First of all, this is the influence of operating parameters (steam flow rate and temperature, fuel and air flow rates) on the combustion performance in the oil-steam burner being developed. The aim of the work is complex laboratory and experimental studies of the characteristics of fuel combustion in a new burner with a controlled excess air ratio. Forced air supply to the combustion chamber of a steam-oil burner is a novelty of the burner under study. Based on the results of laboratory studies, the optimal ratios of operating parameters were found (fuel, steam and air flow rates: 1:0.8:2.75), which provide the best thermal and environmental performance (NOx<35 ppm, CO < 25 ppm). A significant reduction in the content of nitrogen oxides in the flue gases up to 70% was achieved with a high completeness of fuel combustion due to the joint control of steam concentration and excess factor in the gas generation chamber. This claims the proposed burner as a low emission one. To confirm the achieved effect, in this work, for the first time, experimental tests of the burner were carried out under the operating conditions of a low-power boiler plant (10–40 kW). Successful tests prove the efficiency of using the developed burner for solving the problem of efficient and environmentally friendly combustion of fuel (including liquid combustible waste) for the production of thermal energy at small-scale energy facilities.

Multifaceted Analysis of the Use of Catalytic Additives for Combustion with Hemp Pellets in a Low-Power Boiler

This paper presents the results of a multifaceted analysis of the application of catalytic additives to hemp pellets’ combustion in a low-power boiler. The research concerns the effects of five catalytic additives applied inside the boiler’s combustion chamber—based on TiO2, MnO2, Cu(NO3)2 × 3H2O, H2PtCl6 solution, and 99.5% pure urea solution—on the quality of hemp pellets’ combustion process. For this purpose, technical and elemental analyses of the used fuel were performed. The chemical composition of exhaust gases (NOx, CO, SO2, and PM content) was also examined using an exhaust gas analyzer and a dust meter. The highest reductions in emissions of individual pollutants were for CO (−113%; combustion with Ad3), NOx (−66%; combustion with Ad 4), SO2 (−48%; combustion with Ad3), and PM (−78%; combustion with Ad1). The study also determined the amount of avoided costs due to the use of catalytic additives, as well as the annual prevented CO2 emissions to the atmosphere. Due to rising fuel and energy prices, this study could be helpful for biomass boiler owners who would like to burn locally available raw materials and increase the combustion process’ efficiency.

Analysis of technological conditions for the formation and burnout of carcinogenic pahs in boiler flue gases

THE PURPOSE. The necessity of establishing emission standards for highly toxic substances with carcinogenic properties in the context of the implementation of new principles of state regulation of environmental protection activities at energy enterprises is substantiated and confirmed. The analysis of the features of the formation and burnout of carcinogenic polycyclic aromatic hydrocarbons in the flue gases of boilers during the combustion of coals in lowtemperature conditions of the furnace process is carried out. Based on the analysis, the total and partial indicators of the harmfulness of flue gases were calculated in order to assess and predict the overall toxicity of coal combustion products, taking into account the contribution of carcinogenic substances.METHODS. When calculating the overall toxicity of flue gases, a systematic analysis and generalization of experimental data on the content of carcinogenic and non-carcinogenic polycyclic aromatic hydrocarbons in the combustion products of low-power boilers was applied.RESULTS. As a result of the performed study, the contribution of carcinogenic and non-carcinogenic polycyclic hydrocarbons to the overall toxicity of boiler flue gases during the combustion of Azeysky, Mugunsky, Cheremkhovsky and Tugnuy coal was determined. It is shown that substances such as benz(a)pyrene, fluoranthene, pyrene and phenanthrene significantly affect the level of the total indicator of the harmfulness of combustion products from 38.8 to 53.6%.CONCLUSION. The obtained research results can be applied at energy enterprises at the stage of substantiating the introduction of regime-technological and environmental measures in order to develop measures to improve environmental efficiency through technological rationing of carcinogenic emissions.