Exhaust Gas Heat Research Articles

Influence of N-Butanol-Diesel Fuel Blends on the Performance Characteristics of a Four Stroke, Compression Ignition Engine

Aims: This study investigates the impact of blending n-butanol with diesel fuel on the performance of a single-cylinder, 4-stroke diesel engine under varying engine loads.
 Study design: The performance assessment followed SAE J1349 on a Tec-Quipment TD110-115 4-stroke engine at 1500 rpm with varying loads and fuel samples.
 Place and Duration of Study: The study was conducted for 2 months the at Automotive Engineering Technology Workshop, Federal Polytechnic, Bauchi Nigeria.
 Methodology: The SAE J1349 test protocol was followed, using diesel fuel (D95) and different blended fuel samples (D90, D85, D80, D75, and D70). While diesel fuel generated higher brake power due to its higher calorific value, the D95 blend demonstrated comparable performance to diesel fuel across all parameters.
 Results: The brake power of the D95 blend initially decreased by 69.7% and then increased as the load increased to 2500g and 3000g, indicating improved combustion due to oxygenation. The D95 blend exhibited lower fuel consumption compared to diesel fuel, although blends with higher n-butanol percentages showed increased brake-specific fuel consumption due to lower calorific values, densities, and viscosities. Under maximum load, the D95 blend exhibited higher exhaust gas temperature and heat loss, reflecting the increased fuel quantity required for additional power. Lower heat losses at lower loads were attributed to factors such as lower calorific values, n-butanol's heat of vaporization, temperature differentials between the exhaust and ambient conditions, and engine size.
 Conclusion: The engine load has diverse effects on parameters across different fuel samples. D95 exhibits similar performance to diesel, yet discrepancies arise, especially with higher n-butanol content at lower loads.

Компиляция данных по оптимизации работы трубчатых печей

A great number of processing hydrocarbon raw material units operated at enterprises have heat exchangers of different designs. A significant share among them comes to the special heat exchangers that use the heat of exhaust gases when burning liquid and gaseous fuels – tubular furnaces. Depending on the specifics and type of fuel used, the furnaces differ both in design and in operational parameters. At AT units, AVT units, and gasoline secondary distillation units, HFC furnaces are used to heat hydrocarbon media and are characterized by heating temperatures from 300C° to 500°C. In the units of technological processes of pyrolysis, conversion of hydrocarbon gases, etc., simultaneously with heating and/or overheating of the raw materials, furnaces are used as reactors. The effective use of such furnaces is possible only if there are used engineering methods predicting changes in the technological flow, created on the basis of reliable analytical and experimental materials. The available data is insufficient to develop measures 
 to improve the efficiency and reliability of these units. There are discussed the results of analytical studying the optimizing the operation of tubular furnaces, identified the main disadvantages during their operation, determined methods for assessing the wear of the elements of the apparatus depending on the technological modes (temperature, pressure, medium) and the material of execution in the process of technical diagnostics of equipment to ensure industrial safety. The issues of the influence of design features and of organizing the combustion process of nozzles on the quality indicators of tubular furnaces are considered. The main directions of increasing the energy efficiency of radiant and convection chambers of tubular furnaces are defined.

Enhancing the Fuel Efficiency of Cogeneration Plants by Fuel Oil Afterburning in Exhaust Gas before Boilers

Cogeneration or combined heat and power (CHP) has found wide application in various industries because it very effectively meets the growing demand for electricity, steam, hot water, and also has a number of operational, environmental, economic advantages over traditional electrical and thermal systems. Experimental and theoretical investigations of the afterburning of fuel oil in the combustion engine exhaust gas at the boiler inlet were carried out in order to enhance the efficiency of cogeneration power plants; this was achieved by increasing the boiler steam capacity, resulting in reduced production of waste heat and exhaust emissions. The afterburning of fuel oil in the exhaust gas of diesel engines is possible due to a high the excess air ratio (three to four). Based on the experimental data of the low-temperature corrosion of the gas boiler condensing heat exchange surfaces, the admissible values of corrosion rate and the lowest exhaust gas temperature which provide deep exhaust gas heat utilization and high efficiency of the exhaust gas boiler were obtained. The use of WFE and afterburning fuel oil provides an increase in efficiency and power of the CPPs based on diesel engines of up to 5% due to a decrease in the exhaust gas temperature at the outlet of the EGB from 150 °C to 90 °C and waste heat, accordingly. The application of efficient environmentally friendly exhaust gas boilers with low-temperature condensing surfaces can be considered a new and prosperous trend in diesel engine exhaust gas heat utilization through the afterburning of fuel oil and in CPPs as a whole.

Energy Recovery Based on Exhaust Gas Recirculation and Heat Regeneration Processes Applied in a Firewood Boiler

Energy Recovery Based on Exhaust Gas Recirculation and Heat Regeneration Processes Applied in a Firewood Boiler

Multidisiplinary design optimization of a power generation system based on waste energy recovery from an internal combustion engine using organic Rankine cycle and thermoelectric generator

The research paper mainly deals with waste heat recovery from internal combustion engines (ICE) using the organic Rankine cycle (ORC) and Thermoelectric generator (TEG). Simultaneously recovering the wasted heat of both exhaust gases and coolant, a novel configuration named two-stage is proposed. Then a comprehensive thermo-economic analysis and optimization are conducted. Produced power and total cost rate are selected as the objective function of the optimization. Also, the first and second stage pressures of the ORC system are considered as decision variables. Finally, a sensitivity analysis is performed to study the effect of expander inlet temperature, pumps isentropic efficiency, and expander isentropic efficiency on the objective function.

A study on fuel reforming waste heat recovery engine system fueled with methane

In this study, the potential for improving the thermal efficiency of a waste heat recovery engine system by fuel reforming was investigated. Steam methane reforming was focused because of its endothermic reactions. The effects of engine operating conditions on the exhaust gas temperature and heat were examined experimentally. The effects of the conditions of steam methane reforming on methane conversion, and the increase in the heating value of the reformed gas were investigated by equilibrium calculations. The heat balance of the system was also analyzed. The parameters affecting the thermal efficiency of the system and the conditions for maximizing the waste heat recovery effect were quantitatively identified. The effects of the temperature-efficiency ratios of heat exchangers on the thermal efficiency of the system were also evaluated for practical applications.

Potential of applying the thermochemical recuperation in combined cooling, heating and power generation: Off-design operation performance

Combined cooling, heating and power system (CCHP) as a typical distributed energy utilization technology, is usually installed close to the end-user to satisfy the diverse energy demands, which also has multiple advantages of energy-efficient and environment-friendly. While the simultaneously changing user energy loads brings about a huge challenge for the system energy conversion and regulation process, and then significantly affects the system operation flexibility. Therefore, the new method of thermochemical recuperation (TCR) is employed to enhance the system dynamic energy utilization performances, and also efficiently converts the high-temperature exhaust gas heat into hydrogen-enrich syngas for further application. In this work, by considering the practical system operation, the off-design TCR operation adjustment capacity for the system diverse energy outputs is important, which is extensively investigated. Based on the developed mathematic model, different-size (small, middle and large) gas turbine scenarios are considered, the results indicate that the TCR process effectively optimize the system energy conversion process, and the corresponding power efficiencies are improved by 10.53%–13.87%, 8.56%–14.46% and 14.23%–14.42%, respectively. In addition, with the merits of adaptively coordinating the multi-energy production, the off-design energy outputs boundary of the CCHP system can be extended and then readily match the fluctuant user loads. Specifically, as for the small scale GT-based system application in a hotel building case, the system annual recuperated fuel ratio reaches to 0.54 with the annual coordinated recuperation operation time ratio of 0.70, and then the system operation flexibility is thus enhanced with the annual fuel saving ratio of 6.03%, which also contributes to the CO2 emission reduction. With the favorable potential to optimize the CCHP system operation regulation, the thermochemical recuperation technology provides a feasible pathway to enhance the distributed energy system application feasibility.

საავტომობილო ტრანსპორტი სამაცივრო მოწყობილობით

An obligatory link in the transfer of products from the producer to the consumer is transport, which must ensure the transfer of products without damage, with the maximum preservation of its quality. From this point of view, vehicles for the transportation of agricultural and food products attract special attention, since these products are easily exposed to pressure, temperature and mechanical damage. One of the most important ways to preserve the quality of products during transportation is the use of vehicles equipped with various types of refrigeration devices. For this, it becomes necessary to develop new vehicles that will be equipped with economical, highly efficient and acceptable refrigeration devices. A schematic diagram of a vehicle equipped with an absorption-type refrigeration machine, which is completely powered by the heat of the vehicle's exhaust gases, is presented. R

Design and performance of a laboratory scale pressurized oxy-coal reactor

A pressurized oxy-coal (POC) reactor has been designed, built and tested to investigate key technologies related to oxy-coal combustion including a dry coal feed system, an oxy-coal burner, and a slagging ash management system. The coal feed system utilized a fluidized bed to convey pulverized coal with CO2 from a coal bed into the reactor. The reactor has diagnostic capabilities including optical access, embedded thermocouples, fuel and gas flow rates, exhaust gas analysis (CO2, CO, NO, O2) and heat flux. At 13.6 atm and a firing rate of 89 kWth a mean feed rate of 12.5 kg/h was established with large fluctuations of approximately ±2 kg/h. After polishing the fluid bed walls and removing accumulated large particles on the fluid bed screen, a coal feed rate of 7 kg/h ± 0.5 kg/h was demonstrated. The measured wall temperature profiles, heat flux, and exhaust gas concentrations enabled evaluation of the burner characteristics. The burner produced a long flame as designed but increased mixing is required to improve burnout. Flowing slag was obtained as designed when the reactor remained at the required firing rate and stoichiometric ratio to keep the walls above the slagging temperature.

Thermodynamic analysis of two-stage and dual-temperature ejector refrigeration cycles driven by the waste heat of exhaust gas

This paper presents two-stage and dual-temperature ejector refrigeration cycles (TDERCs) driven by the waste heat of exhaust gas. One-dimensional modelling of the ejector is performed, and thermodynamic analysis for the TDERCs is carried out. Based on simulation results, R1234yf/R1234ze with a mass fraction of 56.2% R1234yf is selected as the working fluid, showing an improvement of 5.64% in COP over R134a under the basic operating condition. Comparing with the TDERC1, the TDERC2 shows improvements of 1.07% and 0.69% on the COP and exergy efficiency with a superheater outlet temperature of 300 °C, while the cooling capacity is reduced by 0.107 kW. Moreover, the multi-objective optimization results indicate that the TDERC2 has improvements of 1.20% in COP and 0.666 kW in cooling capacity compared to the TDERC1 under the optimum operating condition. Overall, the TDERC1 can provide a larger cooling capacity with sufficient waste heat of exhaust gas, while the TDERC2 is more suitable for limited waste heat or low exhaust gas temperature due to its higher COP. The simulation results reveal the advantages and disadvantages between the TDERC1 and TDERC2 under different operating conditions and provide guidance for refrigerated and frozen applications in light refrigerated trucks.

Analysis of Exhaust Gas Heat Utilization in Waste Heat Recovery Power Generator at Indarung V Factory PT Semen Padang

Increasing energy efficiency in the cement production process at PT Semen Padang is carried out by reusing exhaust gas to produce electricity using Waste heat recovery power generation (WHRPG) with a capacity of 8.5 MW. WHRPG is a technology for utilizing exhaust gas heat as a source of heat energy to heat feed water into steam by using a suspension preheater (SP) boiler and air quenching cooler (AQC) boiler. This study aims to calculate the power potential of the steam heat influenced by the steam temperature and the mass flow rate of the steam produced by the boiler, to calculate the efficiency of the boiler using the direct method by comparing the boiler output heat against the boiler input heat, to calculate the turbine efficiency based on the difference between the steam enthalpy enter the turbine against the steam enthalpy out of the turbine and the isotropic enthalpy of the steam out of the turbine and to calculate the power generated by WHRPG at PT Semen Padang. The results obtained in this study are the total potential power of steam heat is 19.778 MW, the boiler AQC efficiency is 70.30%, the boiler SP efficiency is 94.04% and the turbine efficiency is 78.64%. The electricity generated by PT Semen Padang's WHRPG is 3.70 MW.

Numerical Calculation of Wet Exhaust Gas Condensation in the Heat Exchanger

Based on the background of waste heat recovery of gas-fired boiler, this paper studied wet exhaust gas condensation heat transfer using numerical methods. The calculated results indicated that with the exhaust gas Re number increases, heat flux, and Nu number gradually increase, while the Eu number decreases simultaneously. Besides, the variation trend of the Nu and Eu number gradually reduced with Re number increases. With inlet exhaust gas temperature increase, the Nu number increases, and the Eu number decreases. Meanwhile, Nu number and Eu number increases with the increase in wall temperature. On this basis, the empirical correlations for calculating Nu and Eu numbers are obtained, and the deviation between the calculated values and the numerical results is within ±8%. The conclusion of this study provides basis for heat exchanger design in wet exhaust gas waste heat recovery.

A self-condensation supercritical carbon dioxide Rankine cycle system realized by absorption refrigeration

A novel self-condensation supercritical carbon dioxide (sCO2) Rankine cycle system in which a lithium bromide-water absorption refrigeration cycle is used to utilize the waste heat of exhaust gas from the carbon dioxide power cycle and provides a cold source to condense the exhaust gas is proposed. The new system avoids the huge compression power consumption of the sCO2 Brayton cycle system by replacing the compressor with a more efficient pump and the requirement of an extra low-temperature cold source. The power consumption during pressurization, thermal efficiency and levelized cost of electricity (LCOE) of the new integrated system are 26.50% lower, 3.77% higher and 4.32% lower than those of the stand-alone regenerative sCO2 Brayton cycle system, respectively. Parametric analysis is carried out to study the effects of key parameters on the thermodynamic and economic performance of the integrated system. The results show that the generator temperature, maximum system pressure and maximum system temperature have a positive effect on the thermal efficiency and LCOE, while the evaporator temperature and minimum system pressure have a negative effect.

Life cycle assessment of greenhouse gas emissions of typical sewage sludge incineration treatment route based on two case studies in China

The rapidly increasing amount of municipal sewage sludge generated in China necessitates a thorough examination and evaluation of available treatment options. In recent years, thermal-drying and incineration technology has gained popularity, however, it may lead to significant greenhouse gas (GHG) emissions. Nevertheless, the differences in boundary conditions and technological characteristic across various cases may affect emission levels significantly. Therefore, this study utilizes a life cycle assessment to estimate the GHG emissions associated with two typical sludge incineration routes in China: direct thermal-drying combined with coal co-incineration incinerator in Case 1 and indirect thermal-drying and self-sustain combustion in Case 2. The entire treatment processes, containing different functional units, were comprehensively investigated. The results demonstrate that Case 1 and Case 2 produce 1133.33 and 350.89 kg CO2-eq/tDS (sludge dry solid) of GHG emissions, respectively. In Case 1, coal co-incineration produces 828.63 kg CO2-eq/tDS of GHG emissions, accounting for 73.1% of the total GHG emissions. Moreover, the exhaust gas treatment is a significant GHG emission source, accounting for 9.2% and 16.9% of the total GHG emissions in Case 1 and Case 2, respectively. Additionally, the sludge thickening and dewatering unit in Case 2 produces 213.75 kg CO2-eq/tDS of GHG emissions, accounting for 60.9% of the total GHG emissions. Analysis of energy flow and heat balance characteristics indicate that the indirect heat transfer method used in thermal-drying leads to significant heat loss, which limits heat recovery potential and hinders GHG emission reduction. This study proposed a scenario case based on Case 2, addressing the issues with the improvement of heat transfer process and reduction of electricity consumption, potentially reducing GHG emissions by 8.8%. Additionally, applying an exhaust gas heat recovery system could further offset up to 22.8% of the total GHG emission.

Comparison Study of Four Typical ORC Configurations for Different Waste Heat Characteristics of Engine

The organic Rankine cycle (ORC), as the most promising technology for engine waste heat recovery, has many configurations available to match the complicated engine waste heat conditions. This paper is aimed at revealing the characteristics of the engine waste heat condition for which different ORC configurations are matched so as to give selection guidance. The engine waste heat sources are characterized by the exhaust gas temperature (300°C-650°C) and the heat ratio of the high temperature waste heat to low temperature waste heat (0.5-1.5). Four mostly investigated configurations including the single-loop ORC, the cascade dual-loop ORC, the dual-pressure ORC, and the CO2 transcritical Rankine cycle (CTRC) are selected and modified to enable efficient utilization of all waste heat sources. Their thermodynamic performance is optimized for different waste heat characteristics. The results show improvements in net power for all configurations when exhaust gas temperature and heat ratio rise from 300°C, 0.5, to 650°C, 1.5, respectively, of which the high-temperature split CTRC (HTS-CTRC) recorded the largest increase of 183.58%, while the split regenerative ORC (SR-ORC), dual-pressure ORC (D-ORC), and split cascade ORC (SC-ORC) increased by 17.41%, 23.71%, and 35.45%, respectively. Two selection maps are established to provide general references for quickly selecting the configuration according to different waste heat characteristics whatever the engine type and operating conditions.

Design and Fabrication of Exhaust Gas Heat Recovery Power Generation System

Abstract: This paper proposes and implements a waste heat energy recovery system for internal combustion engine automobiles, including gasoline vehicles. In modern days agricultural sector is plays an important role, so for that we need electrical energy for lighting effects in night times. The key is to directly convert the heat energy from automotive waste heat to electrical energy using a turbocharger, which is then regulated by a DC–DC Ćuk converter to charge a battery using maximum power point tracking. Hence, the electrical power stored in the battery can be maximized. The experimental results demonstrate that the proposed system can work well under different working conditions, and is promising for automotive industry.

Theoretical study of a downdraft gasifier, microturbine, and organic Rankine cycle fuelled by date molasses waste for distributed generation applications in Iraq

AbstractThe main objective of this work is the modeling of a combined heat and power (CHP) system that transforms waste from manufacturing date molasses in the Babylon province in central Iraq into electrical and thermal energy. A compact CHP facility that uses date waste (pomace and pits) as a feedstock is the subject of theoretical modeling and simulation research. The planned power plant consists of a downdraft gasifier, a microturbine (MT), and an organic Rankine cycle engine (ORC) as a bottom unit to maximize electric generation by recovering the MT exhaust gas heat and achieving a maximum electric output. The net electric production is 361.68 kW (280 kW from the MT unit and 81.68 kW from the ORC unit). To determine the best‐working fluid for the ORC system as a whole, three working fluids, including isopentane, benzene, and R113, were investigated. The temperature difference between the heat source and the fluid's boiling point is a key factor in choosing a more appropriate ORC working fluid. Isopentane is the most suitable working fluid for CHP applications, according to the findings of the simulation. The electric efficiency achieved is 30%, and the overall efficiency of the CHP plant was 56.87% from the gasification of date pits. The simulation results showed a satisfactory producer gas lower calorific value of 3.92 MJ k‐g‐1 for date pomace and 4.65 MJ k‐g‐1 for date pits, and cold gasification efficiencies of 73% and 76% for pomace and pits, respectively. © 2023 Society of Industrial Chemistry and John Wiley & Sons Ltd.

Achieving Zero-Impact Emissions with a Gasoline Passenger Car

The Euro 7 legislation and the Zero-Impact Emissions concept aim at significantly improving air quality. Technologies that reduce pollutant emissions beyond current gasoline passenger cars have already been intensively investigated, but a holistic system layout considering extended boundary conditions is missing so far. This paper therefore develops technical solutions to achieve a Euro 7 scenario and Zero-Impact Emissions for a 2030+ vehicle. First, challenging test scenarios are identified to develop compliant vehicles. The scenarios cover extreme conditions in real-world driving, such as hot and cold ambient conditions, stop-and-go in rural areas or high speed and steep gradients on highways. Different technology options are discussed and selected for the investigations. An empirical–physical simulation model for the exhaust gas aftertreatment system is extended with new technologies, such as an electrical heater disc in front of the catalyst or a burner in the exhaust system. In addition to stoichiometric engine operation and increased catalyst volume, the results show that the expected Euro 7 regulations can be achieved in all extreme scenarios by combining additional exhaust gas heating with engine power limitation or pre-heating. Moreover, even Zero-Impact Emissions are achieved in most cases with the same technology options.

A Vertical Fountain Dryer Adjusted for Sawdust and Wood Chips Drying

This article presents the preliminary results on the drying process in a fountain dryer designed and adapted to drying waist sawdust and/or chips of various morphology and moisture content. In terms of drying technology, it is important to reduce the demand for heat and electricity. The phenomena occurring during the drying of sawdust in a fountain dryer were analyzed. Modifications of a typical fountain dryer were proposed in order to dry the chips, to obtain appropriate moisture and quality suitable for the process of their further granulation for the production of pellets. The test stand and the most important properties of the fountain dryer were described and discussed. Such characteristic aims of the device, i.e., efficiency, combustion, air and exhaust gas flow measurements, among others, were presented. The characteristics of the sawdust drying curves as a function of temperature were also determined. Computer simulations of heat exchange, air, and exhaust gas flow velocities were also performed and compared with the results obtained directly from the modified test stand. The maximum combustion of sawdust measured during startup of the furnace was 0.14 m3/h, which is 0.46 m3 of the fuel consumption for the production of 1000 kg. Drying times of wet sawdust is relatively short and takes ~50 s for (weight of wet sawdust 4.75 kg, with moisture of 35%) the relatively low air temperature of 175 °C.

Thermodynamic design and analysis of SOFC/PEMFC hybrid systems with cascade effects: A perspective on complete carbon dioxide capture and high efficiency

To capture as much carbon dioxide as possible while minimizing the performance degradation, this study proposes two solid oxide fuel cell (SOFC)/polymer electrolyte membrane fuel cell (PEMFC) hybrid systems. One is a hybrid system in which the PEMFC not only generates power, but also performs the role of CC (hybrid system 1). The other is a hybrid system in which pressure swing adaption (PSA) is incorporated to capture carbon dioxide, and consumption of hydrogen in the PEMFC is maximized (hybrid system 2). In addition, an organic Rankine cycle (ORC) was added to further improve the performance of the hybrid systems by utilizing the waste heat of exhaust gas. The cascade effects between SOFC and PEMFC contribute to achieving nearly complete CC and high efficiency. Especially, hybrid system 2 achieved 10% and 5%p improvements over the stand-alone SOFC system in net power and efficiency. It is promising in that the proposed systems utilizing cascade effects can achieve nearly zero carbon emission and high efficiency despite the use of natural gas without hydrogen supply. In other words, the proposed systems are expected to contribute to the realization of carbon neutrality without waiting for the technological maturation associated with hydrogen.