Boiler Fuels Research Articles

Production and characterization of two-step condensation bio-oil from pyrolysis

The goal of this project is to investigate the potential of fuel production directly from slow pyrolysis of straw pellets without further refining. A two-step condensation was used to separate liquids from the volatiles. The thermal process chosen is slow pyrolysis at 500°C to couple the fuel production with carbon capture by maximizing the char production alongside bio-oils collection. Condensation parameters were tuned to improve the pyrolysis oil quality. To assess the oil quality some requirements on marine fuels, bio-oils and boiler fuels were taken as reference. Three condensation conditions were inspected: the best pyrolysis overall process was repeated three times for a total of five pyrolysis processes (lately referred to as runs). As expected, the bio-oil characteristic changed with the condensation temperature. As a result of lowering the bio-oil condensation temperature, the bio-oil results less viscous, less dense, with lower heating value and with higher water content. The final bio-oil produced was almost compliant to ISO 8217:2017 for residual marine fuels K 380, apart from water content and acid number, while it was almost compliant for the standard EN 16900:2017 for industrial boilers fuels, apart for the kinematic viscosity. It was assessed that the char is produced with an average yield of 27 w% on dry basis, while bio-oil has a yield between 5 and 10 w%. It is possible to recover an average of 72 % of the total energy contained in the straw in the valuable products, gas, char and bio-oil. The carbon captured with charcoal was around 49 w% of the total present in straw. The pyrolysis experiments were performed using an innovative semi-batch, packed-bed reactor with gas re-circulation and a new two-fraction condensation appliance that is DTU patented. The innovation is both in the reactor, where the gas is directly heated and flushed back into the pyrolyser, and in the condensation section, where the bio-oil is separated from the water fraction during the pyrolysis. The company Stiesdal SkyClean A/S showed interest in further development and scale up of this pyrolysis and condensation system.

Study of the Flame Characteristics of Biodiesel Blend Fuel in a Semi-industrial Boiler

Study of the Flame Characteristics of Biodiesel Blend Fuel in a Semi-industrial Boiler

DETERMINATION OF THE FEATURES OF THERMAL DECOMPOSITION OF SUNFLOWER HUSK IN A FLUIDIZED BED

Sunflower husk (SH) is a plant waste fuel. The carbon content in different samples of SH ranges from 40.5% to 54.5% in an operating state, with ash content ranging from 1.5% to 8.5%, moisture content ranging from 6.9% to 9.5%, chlorine content ranging from 0.05% to 0.3%, and lower heating value ranging from 14.5 MJ/kg to 20.5 MJ/kg. These characteristics make it a suitable substitute for fossil fuels in power boilers. Waste-to-energy (WTE) technologies are rapidly developing worldwide, offering the potential for generating renewable energy from waste, including agricultural and food industry waste such as SH. According to our estimates, Ukraine has an annual energy potential of approximately 3.4 million tons of SH or about two million tons of fuel equivalent. Approximately half of this volume is currently being burned in oil extraction plants' boilers; however, up to one million tons of SH end up in landfills annually, resulting in significant energy losses. To develop new and improve existing WTE technologies that utilize SH as a fuel source, it's essential to understand the thermal processing characteristics of SH under conditions similar to those found in different zones within real power boilers - specifically the heating of fuel particles at rates up to 500 °C/s over a temperature range of 500–1000 °C. In this study, we aimed to investigate the thermal processing characteristics by subjecting SH particles within a laboratory fluidized bed reactor to high-speed heating within the aforementioned temperature range. During rapid heating between 500–1000 °C temperatures range, SH particles undergo conversion into volatile compounds and solid carbon residue. Two distinct stages can be observed on the dynamic yield curves for volatiles. The release and burnout of volatiles occurs during the first stage while the second stage involves coke ash residue burnout. We obtained empirical temperature-dependents for total heat treatment time and carbon residue burnout time under fast heating conditions in the investigated temperature range. The stage of carbon residue combustion is the most enduring and determines the overall duration of thermal treatment. This stage determines the degree of fuel transformation, especially in cases where low-reactivity carbon residue enters the low-temperature combustion chamber area of the boiler. The obtained regularities have practical significance in designing combustion chambers for thermal processing of sunflower husk.

Effect of cavitation treatment of coal-water slurries on a droplet average size in a jet

Relevance. Transition to environmentally friendly energy technologies, due to modern requirements for environmental protection, involves the search and creation of new energy sources, including fuels. One of the ways to meet these requirements and maintain the same level of energy production by thermal power plants is the transition to multicomponent fuels. The most promising and affordable boiler fuels from the point of view of energy, ecology and economy are coal-water slurries. In this regard, the study of the properties and characteristics of such fuels is relevant in many countries. Aim. Experimental studies of the effect of the coal-water fuel cavitation treatment duration on a droplet average size in a jet after spraying with a pneumatic nozzle and substantiation of the efficiency of such approach for practical application. Object. Experimental studies were carried out with coal-water slurries based on long-flame coal (D grade) with addition of 10 and 20 wt % by weight of pyrogenetic liquid. A slurry, consisting of just coal and water, without the addition of pyrogenetic liquid, was used as a reference sample. Method. The coal-water slurries were prepared in a rotary hydrodynamic cavitation generator. A pneumatic nozzle with external mixing was used to spray the coal-water slurries. The average size of fuel droplets after spraying was determined using the Interferometric Particle Imaging method. Results. Experiments on the preparation of coal-water slurries with pyrogenetic liquid showed an increase in the dynamic viscosity of the fuel. An increase in the duration of treatment of the slurries in a rotary hydrodynamic cavitation generator reduced the viscosity by 54%. The average size of droplets in the jet was reduced by 22%.

Transition and Future View of Marine Boiler Fuel

Transition and Future View of Marine Boiler Fuel

Верифікація CFD-моделі теплообміну і гідродинаміки для спалювання непроектного палива у паровому котлі ТПП-210А

Верифікація CFD-моделі теплообміну і гідродинаміки для спалювання непроектного палива у паровому котлі ТПП-210А

Utilization of Wood Waste for Boiler Fuel (Case Study at PT. Putra Albasia Mandiri)

The wood processing production system in its activities always produces waste in the form of husks or pieces of wood. The opportunity to control wood waste can be used to heat boilers as a substitute for fuel oil. This study on the use of wood waste was carried out to assess technical, economic and environmental aspects. An assessment of the technical aspect was carried out to see the efficiency of using wood waste compared to fuel oil. Financial aspects are an important consideration in utilizing wood waste, while environmental aspects. Studies show that diesel fuel consumption is higher than wood waste fuel consumption, however boiler efficiency is higher using oil fuel compared to wood waste fuel, namely 70%: 20%. Financial analysis using NPV shows that this wood waste fueled boiler is economically feasible. From environmental aspects, it is known that fuel consumption for one year for wood waste fuel produces CO2 emissions of 1,207.36 tons, which is lower than CO2 emissions from burning diesel which is 6,808.31 tons.

Application of brewers’ spent grains as an alternative biomass for renewable energy generation in a boiler combustion process

In most industries that generate consumer products the main source of electrical energy comes from burning wood or fossil fuels in boilers. However, the use of these non-renewable fuels poses a huge problem for the current energy matrix and for the environment, which makes new alternatives necessary for a more environmentally friendly scenario. In view of this, our study evaluated the application of brewers’ spent grains (BSG) as an alternative biomass for energy generation in an industrial cogeneration system. For this, different blends of BSG and eucalyptus wood chips were used for steam generation. In addition, the effect of two different dehydration conditions on the drying kinetics of BSG were evaluated. The BSG presented an initial moisture content of 77.68%, 0.52% ash, mean particle size of 0.28 mm, density of 113 kg m–3, and lower calorific value of 17.84 MJ kg–1, making it suitable for energy recovery in a cogeneration system. Outdoor drying under external conditions can be applied to remove the moisture content from BSG, which is a low-cost strategy for further application in the drying process. From the biomass blends, the use of 80% BSG and 20% wood chips promoted better characteristics for application as fuel in a cogeneration system. The use of BSG promoted a reduction in the use of wood chips as fuel and generated a savings of approximately 9 thousand USD annually for the simulated system (80% BSG and 20% wood chips), a reduction of 82% of the cost, when comparing with a system using only wood chips. Therefore, the biomass by-product generated from beer production can be used to produce renewable energy in a cogeneration system, replacing the use of wood chips. The waste-to-energy strategy evaluated in this study can be a promising alternative for a circular economy transition, reducing the waste generated in breweries and promoting the recovery of renewable energy that can be applied in situ, making the entire industrial system become a biorefinery, using its main waste as biofuel to generate clean energy, promoting an energy transition to an increasingly cleaner energetical matrix.

Developing alternatives to hydrocarbon via pyrolysis and gasification of industry residual biomass

<p>Pyrolysis and gasification are thermal treatment processes using biomass to produce biofuels that can replace fossil fuels in industrial boilers and furnaces. This paper discusses the potential utilization of four types of residual biomass highly produced in the Argentina Northeast (NEA) region, i.e., rice husk, an agricultural waste rich in cotton husk, carob sawdust, and spent red quebracho sawdust, as raw material. Pyrolysis liquid product yields were 34–51 wt% and char yields were 29–40 wt%; tar represented 16–23 wt%. For gasification, gas yields were between 45.6 wt% and 65.7 wt%; as for tar, it represented 2.4–14.1 wt% of initial biomass, and char yields were 31.4–40.3 wt%. Characterization of all products was performed to clarify their potential applications. Bio-oils, i.e., aqueous fractions of pyrolysis liquid products, have high water content (77–88 wt%), that is why they have lower density and viscosity than tars, oil fractions of pyrolysis liquids. However, chemical stability of bio-oils may vary, and their heating values are much lower than the heating values from tars. Based on these, it is possible to concluded that tar is the product with increased added value and higher energy properties. Efficiency of gasification and heating values of the gases obtained were high for waste rich in cotton husk and spent red quebracho sawdust, suggesting a good potential for the utilization in gasification processes. Additionally, char composition and properties for all biomasses, from both process, show that it is feasible to use them in several new applications.<strong></strong></p>

The combustion of torrefied biomass in commercial-scale domestic boilers

The use of solid renewable fuels in domestic-scale boilers, DSB is especially common in places where the distribution of other renewable energy sources is strongly limited (mountain and foothill regions). High moisture content and limited ventilation have a destructive impact on wood pellets' stability. Torrefaction of biomass is recognized as a possible way to enhance the wood pellets’ hardness under wet conditions. It was found that the maximal water uptake for torrefied biomass after its water immersion was only 18.7 wt%. In this work, the combustion performance and emission of main pollutants during the combustion of thermally–treated biomass are analyzed using two types of boilers: coal-fired 25 kWth (retort burner) and biomass-fired 10 kWth (pellets burner). The best results were obtained during the combustion of torrefied biomass in a 10 kWth DSB, i.e. emission of CO 218 g/GJ, SO2 2.5 g/GJ, NOx 111 g/GJ, and particulates 10.5 g/GJ, boiler efficiency of 90.23%. The combustion of torrefied biomass met the requirement of a 5th-class boiler according to the PN-EN 303-5 standard. Thermally–treated biomass can be used as a substitute fuel in DSB. Nevertheless, the boiler construction can be improved to obtain lower emissions of CO.

Rate-based modeling and energy optimization of acid gas removal from natural gas stream using various amine solutions

Reduction in energy consumption of industrial plants is always an essential need due to high cost, CO2 emissions and global warming caused by energy supply from fossil fuels for boilers and electricity consumers. Iran has been struggling to compensate the lack of gas supply for domestic and industrial demands in winter within the past decade despite of having large natural gas resources. One of the most economical methods to decrease energy requirements in hydrocarbon plants is process improvement and revamping by changing existing solvents. There are already 44 identical acid gas removal units under operation in the South Pars Gas Complex (located in Iran) with the same feed composition. The gas-sweetening unit in the Phase 12, operating with the solution of 45.5 wt% methyldiethanolamine (MDEA), was modeled by Aspen Plus for acid gas removal (CO2 and H2S) as a rate-based model with the application of electrolyte non–random two–liquid (E-NRTL) activity model and Peng–Robinson equation of state in addition to the actual characteristics of the absorber and regenerator, and the operational conditions of the gas and liquid streams. After validation of the model by the real data from the plant, the incumbent amine solution was replaced with five proposed amine solutions – one single and four blended amine mixtures – in the same mass concentration to select the most efficient alternative from the aspects of outlet acid gas concentration, H2S content in the treated flash gas, required total power, reboiler power supply, and regeneration heat duty. The simulation results revealed that H2S was sharply absorbed on the top of the column, while CO2 was smoothly removed from the gas phase to the MDEA and blended solutions along the absorber and it occurred at the bottom of the column for the DEA solution. The blended amine solution of 1.5 wt% sulfolane + 44 wt% MDEA (Sulfinol-M) has shown to be the most appropriate option instead of the solution of MDEA compared to other suggested absorbents, with several advantages such as higher selectivity of H2S over CO2, low temperature bulge, highest H2S loading, and outlet sweet gas flow rate while required total power, reboiler power supply, and regeneration heat duty were reduced by 21.19%, 21.26%, and 23.54% respectively. The operational conditions of the unit with the application of the Sulfinol-M solution were optimized to achieve three specifications (constraints) and the minimum required total power (objective function) through a sensitivity analysis and optimization using a genetic algorithm to assure the reliability of values for three independent parameters, namely, amine solution temperature, amine solution flow rate, and gas temperature. The optimum limits and values of these parameters were 47–50 °C, 220 – 240 ton/h, and 34 °C respectively.

Production of a Biomass Briquette as a Boiler Fuel for Sustainable Steam Power Generation

This work focused on the production of biomass briquette as a boiler fuel for sustainable steam power plant for electricity generation. Most existing power plants rely on fossil fuels, which are nonrenewable and hazardous to the environment. Biomass briquettes made with biomass materials, which are renewable can serve as a sustainable source of fuel for firing a boiler of a power plant. Producing biomass briquettes with improved characteristics is still a big challenge due to varying characteristics of the biomass materials. In this work, the physical, chemical (volatiles matter, Sulphur and ash contents), mechanical and combustion (energy values and burning rate etc.) characteristics of the un-carbonized and carbonized biomass briquettes produced with ground shells, sawdust and waste paper materials were determined to compare their suitability for use as a sustainable boiler fuel for steam production for power plants. The results indicated that the produced briquettes can serve as a viable source of fuel for firing the boiler of a power plant. The energy values of the produced briquettes are higher compared to others available biomass briquettes in the literature. The low Sulphur, moisture and ash contents of the produced briquettes also indicated their suitability for use as a boiler fuel.

Thermal Characteristics of Coconut Shells as Boiler Fuel

Agricultural waste products, such as wood, rice husk, corn waste, and coconut shells, are abundantly available and can potentially be used as an energy source, particularly for direct combustion in boilers. Because coconut production increases every year, it would be useful to find an alternative use for coconut shells, which are a type of coconut waste. As coconut shells can be used as fuel in boilers, the aim of this study was to evaluate the thermal characteristics of coconut shells in this regard. This study used experimental results to evaluate the performance of a boiler when coconut shells were used as solid fuel. The variations in feed rate were 5, 7.5, and 10 kg/h, and the water flow rates varied between 1 litre per minute (lpm), 2 lpm, and 3 lpm. Temperature data were collected every second via data acquisition , and the mass flow rate of the flue gas was collected every 5 min using a pitot tube equation. One of the parameters evaluated in determining the success of coconut shells as boiler fuel is the thermal efficiency of the boiler. The results showed that the maximum thermal efficiency reached approximately 62.04%, and the maximum flue gas temperature was approximately 500 ℃ for a biomass mass flow rate of 7.5 kg/h. The maximum water temperature of the boiler was 99 ℃, which was reached at a minimum water flow rate of 1 lpm. The results showed that coconut shells are suitable for use as boiler fuel.

Emission factors of industrial boilers burning biomass-derived fuels

ABSTRACT Boilers are combustion devices that provide process heat and are integral to many industrial facilities. Historically, outside of the pulp and paper industry, most boilers burned fossil fuels, although interest in decarbonization has been leading to an increased use of renewable fuels in boilers. These boilers, including those in the biorefineries, are often large sources of air pollutant emissions, and the characterization of these emissions is critical to obtaining air permits and ensuring protection of the surrounding air quality. Several industrial boilers and new biorefineries allow utilization of biomass-derived fuels (e.g. wastewater sludge, lignin, etc.) produced during their operation as a fuel for the boiler to meet process energy needs. However, there is limited empirical data on emission factors for the burning of unconventional fuels, such as solid-gas mixtures containing biomass residues. To fill this gap, we carry out a comprehensive data survey, collecting information on emission factors for boilers burning either a single or a mixture of solid and gaseous biomass-derived fuels. We review multiple hard-to-obtain and unconventional data sources, such as air permit applications, stack test data, and industry-sponsored data collection efforts, to compile emission factors for biomass-derived fuels. We then compare this data with wood residue emission factors from the U.S. Environmental Protection Agency’s AP-42 emission factor database. Our results indicate that the emission factors for boilers burning unconventional fuels vary widely depending on the fuel composition, boiler type, and fuel characteristics. Overall, we find that median emission factors of selected biomass-derived fuels are typically lower than those of wood residue boilers in AP-42. The information collected herein could be useful to permitting agencies and industries utilizing boilers who may want to reduce the carbon impact of their facilities by combusting biomass-derived wastes for process energy needs, for more accurate emission estimation for permitting. Implications: Emission factors are often used for air permitting, specifically for emission estimation purposes. This study carries out a comprehensive data survey of emission factors burning unconventional biomass-derived fuels from underutilized sources such as air permits, stack test data, and industry-led efforts, and compare the results to EPA’s wood residue emission factor database. The results from this study can be used can be used by multiple stakeholders such as air permitting agencies, industries burning biomass-derived fuels, and biorefineries, that utilize more advanced boiler technologies. The findings can help mitigate risks to industry owners and operators and helps to avoid delays in obtaining the required air permits that arise due to inappropriate emission estimates in permit applications.

Optimal Composition of Palm Oil Biomass to Minimize Biomass Power Plants’ Greenhouse Gases Emission

Abstract The increasing energy demand and rising concern about climate change have become two significant factors in finding alternative energy sources other than fossil fuels. Biomass has been implemented by several tropical countries such as Indonesia and Malaysia to answer this challenge by utilizing palm oil by-products as boiler fuels to generate steam for palm oil mill (POM) processing as well as for electricity generation. Fiber and kernel shell have become two major palm oil residues that have been implemented for this purpose. Moreover, empty fruit bunch (EFB) can also become another alternative biomass to fuel the boiler. This study is aimed at analyzing and optimizing the utilization of fiber, shell, and EFB by adjusting percentile contents of those three constituents and evaluating the CO2 production. The result of this analysis indicates that the best composition to minimize the CO2 of the biomass power plant is using 70% fiber, 0% shell, and 30% EFB. However, the increase of NO2 and SO2 must also be considered to find the correct balance between those three emissions. In addition, EFB should be pretreated (drying and shredding) before the combustion to reduce the water content and the dimension of EFB.

Effect of the Specific Features of the Torch Aerodynamics on the Integrated Efficiency of the Multifuel Boiler

This scientific paper gives the literature review emphasizing that the overwhelming majority of the operated boilers are equipped with vortex burners. These burners are characterized by an increased NOx formation, low operation reliability of screen tubes and convective heating surfaces, small maneuverability range and insufficient economical indicators. The defining role of the aerodynamic organization of the furnace processes affecting the operation efficiency of the boilers was shown for the case of the combustion of the energy fuels of a different type. Hence, the problems of an increased reliability, maneuverability, environmental safety and economical operation of the boilers are rather topical. The above problems faced by Ukraine today have been essentially exacerbated due to the fact that most boilers of the thermal power plants have a depleted resource and the production of new boilers (especially high power boilers) was actually stopped. The use of vortex burners with the traditional counter layout on the two opposite furnace walls is peculiar for the overwhelming majority of modern high power boilers in Ukraine and abroad. In this case, the central zone of the furnace is designed to provide the collision of the burner torches of opposite walls and a high-temperature burning core is created. In the case of gas –oil boilers, the availability of the high-temperature core results in an intensified formation of the thermal nitrogen oxides and a decreased operation reliability of the metal of furnace screens. The torch throw onto the side furnace walls during the combustion of fuel oil results in an essential decrease of the operation reliability of the screen tubes due to a high-temperature hydrogen sulfide corrosion. This paper highlights the issues of the effect of the specific features of the torch aerodynamics on the integrated efficiency of the boiler operation and the optimization of the layouts for the combustion of energy fuels in the multifurnace boilers for further reconstruction of the boilers to reduce the emission of harmful substances, increase reliability and economicity of their operation and enlarge the steam load carrying range.

INVESTIGATION OF THE FUEL-AIR FLOW INSIDE A VORTEX FURNACE WITH A FLUIDIZED BED USING A SPECIAL AIR-DISTRIBUTING NOZZLE

The article presents the results of an experimental study of the fuel-air flow inside a vortex furnace with a fluidized bed using a special air distribution nozzle. Nowadays, the issue of dependence on fossil energy resources is the most important problem for the countries of Europe. One of the promising solutions to this problem is the use of vortex solid fuel furnaces for burning low-calorie types of fuel, such as waste from the woodworking and agricultural industries. Our country has developed agricultural and woodworking sectors of the economy, so the amount of waste from these industries is significant, which allows them to be used to cover the energy needs of the state. At the same time, there is a significant number of solid fuel boilers on the territory of Ukraine that can be used for this task. The main difficulties in burning low-grade fuels in solid-fuel boilers are the low level of efficiency of these vortex furnaces and insufficient theoretical information about this. To conduct the experiment, a special installation in the form of a cylinder with a nozzle inside is used. The nozzle has a plate inclination of 15 °, which does not exceed 10% of the total live cross-sectional area of the chamber of the experimental setup. In the course of the experiment, the boundary conditions for the formation of a vortex flow at different amounts of fuel and different air flows were determined, and the values of pressure loss and flow velocity were shown. The results are presented in graphical and tabular form. For example, for 2.9 kg of sawdust, the maximum speed of vortex flow formation is 0.72 m/s, for 5.8 kg this value is 0.57 m/s. The obtained results make it possible to formulate recommendations for the improvement of existing solid fuel furnaces due to the use of special nozzles for the intensification of combustion processes. This creates prospects for the development of the country's energy sector. Keywords: fuel combustion, vortex furnaces, furnace aerodynamics, special nozzle.

Assessment of the Potential for Decreasing Greenhouse Gas Emission in Burning Fuels in Boilers at Thermal-Power Plants (TPP) and Boiler Houses

Assessment of the Potential for Decreasing Greenhouse Gas Emission in Burning Fuels in Boilers at Thermal-Power Plants (TPP) and Boiler Houses

Investigation of the Optimal Tightness of the Combustion Chamber of a Solid Fuel Boiler in Order to Increase its Environmental Friendliness

Investigation of the Optimal Tightness of the Combustion Chamber of a Solid Fuel Boiler in Order to Increase its Environmental Friendliness

Engineering And Economic Analysis of Sawdust Biomass Processing As A Co-Firing Fuel In Coal-Fired Power Plant Boiler Pulverized Coal Type

One type of alternative fuel that has the potential to be developed and can contribute significantly to the NRE mix is biomass. The significance of the energy mix is obtained from the use of the co-firing system at the Coal-Fired Power Plant (CFPP) by mixing coal fuel with biomass such as sawdust. Sawdust biomass as cofiring material for CFPP is very efficient because it has energy content and availability that is easy to manage. The aim of this research is to make technical and economic analysis of sawdust biomass as solid fuel for pulverized coal CFPP Co-firing type boiler. The research stages are mapping the potential of sawdust biomass to determine the availability of potential biomass around the location of the co-firing, analyze the technical side and specifications contained in sawdust biomass raw materials to determine the suitability or feasibility of pulverized coal type CFPP specifications, and analyze the economic feasibility of developing sawdust biomass processing technology to determine the cost of production of sawdust biomass so that later it will not have a technical and financial impact. The results of the economic analysis show that the sawdust biomass production business is feasible with NPV parameters > IDR 5,252,097,371, IRR=11.1% and payback period=7.7 years. Provided that if the PLTU Rembang buys biomass at a price of Rp. 862,730/Ton. Sensitivity analysis is used to determine the steps to optimize the adjustment of the ability to purchase biomass from CFPP Rembang where the reference limit for the highest reference price for biomass is IDR 782,006. Efforts that can be made to adjust the ability to purchase biomass from the CFPP Rembang include increasing the yield by 20% or reducing the price of wood by 20%.