Increase In Exhaust Gas Temperature Research Articles

IMPROVING THE PLANTS EFFICIENCY OF THERMAL INCINERATION HOUSEHOLD WASTE BY RECOVERING WASTE HEAT

The work is devoted to research on the creation of recovery exchanger for waste heat exhaust gases of household waste incineration plants. The purpose of the work is to develop a technical solution for the heat recovery exchanger of waste incineration plants (WIP) and determine its thermal efficiency indicators. The main objectives of the study were to analysis of the modern experience of using the WIP and establish requirements for the creation of a exhaust gas heat recovery exchanger, develop a new technical solution for the heat recovery exchanger, and determine the change patterns in its main thermal indicators in different operating modes of the WIP. The known methods of thermal calculation of heat exchangers and the results of previous studies on the development and implementation of heat recovery equipment operating on dusty gases were used. The results of work on the creation of a new technical solution for an air-heating heat recovery exchanger with the ability to clean working surfaces from dust deposits are presented. The heat exchange surface of the heat recovery exchanger is composed of steel panels formed by tubes with membranes. The tubes applied have circular flow turbulizators on their internal surfaces. Turbulizators provide heat transfer intensification by 1.4 to 1.8 times with a moderate increase in aerodynamic resistance compared to other methods of heat transfer intensification. The regularities of changes in the main indicators of the heat recovery unit in different operating modes during the year in the practical range of changes in its input parameters were established. The research results show that, depending on the initial temperatures of gases and air, the excess air ratio in exhaust gases and the dust level of the working surface, the heat recovery exchanger provides heating capacity of 72-263 kW; cooling of exhaust gases to a temperature of 107-245 °C; heating of air to 96-220 °C. It was also established that the deposition of dust on the heat exchange surface of the heat recovery unit under the considered conditions leads to a decrease in the heating air temperature by 1.3-1.4 times and an increase in the final exhaust gas temperature by 1.1-1.2 times. At the same time, the heating capacity of the heat recovery exchanger is reduced by half. To increase heat recovery efficiency, it is necessary to periodically clean the working surfaces of the heat recovery unit with compressed air.

EXHAUST GAS ANALYSIS OF DIESEL - CADOBA FARINOSA FORSKK BIO-ETHANOL BLENDED FUEL SAMPLES RUNNING ON COMPRESSION IGNITION ENGINE

The world is facing declining liquid fuel reserves at a time when energy demand is exploding. As the supply decreases and costs rise, everyone will be forced to adopt the alternative energy resources. In order to achieve a secure and stable energy supply that does not cause environmental damage, renewable energy sources must be explored and promising technologies should be developed. This study investigates the effects of exhaust gases of diesel-Cadoba farinosa forskk bio-ethanol blended fuel samples run on a compression ignition engine. The test fuels were prepared; BDE2 (97% Diesel and 2% bio-ethanol volumetric proportion), BDE4, BDE6, BDE8 and BDE10 with 1% biodiesel (palm oil methyl esters) was maintained throughout to prevent phase separation of the ethanol and diesel respectively. The engine performance and exhaust gas analysis were also conducted to investigate the effect of bio-ethanol as diesel fuel extender, with a TD110-115 single-cylinder, four-stroke and air-cooled, compression ignition engine test rig, under different loading conditions, and incorporated with an SV-5Q automobile exhaust gas analyzer was used to monitor and measure the concentration of gaseous emissions, such as; exhaust gas temperature (EGT), carbon dioxide (CO 2), carbon monoxide (CO), and unburned hydrocarbon (HC) from the engine tail pipe. Results of the test revealed an appreciable increase in exhaust gas temperature of 16.66% due to the rise in cylinder pressure and temperature respectively. An appreciable decrease in HC, CO and CO 2 15.7%, 37.5% and 15% respectively emissions was recorded for all blended fuel samples with the exception of diesel. While, the least CO and CO 2 emission levels were observed for BDE10 fuel samples. On the account of its satisfactory engine performance behavior, fuel conservation advantages, and inherent greenhouse gas mitigation potentials, the candidacy of Cadoba Farinosa Forskk bio-ethanol and diesel blends, offers the promise of a prospective fuel for compression ignition engines.

Результаты исследований по снижению вредных выбросов судового дизеля путем подачи в цилиндр добавочных компонентов

A study was conducted in order to reduce harmful emissions of marine diesel by feeding additional components into the cylinder due to stricter requirements for the level of harmful emissions from marine power plants. It is noted that it is most difficult to achieve compliance with environmental requirements for diesel engines that have been built for more than 20 years and have been operated on ships for a long time. The use of complex methods to improve their environmental characteristics can lead to a significant increase in the cost of measures to modernize them and increase operating costs. The supply of additional components to diesel cylinders to reduce harmful NOx and COx emissions is considered. The experiments were carried out on a marine diesel generator based on diesel 1H17.5/24 with the use of water and ethanol supply to the cylinder. As a result of high-pressure water supply, a 30% reduction in NOx was noted, and no reduction in COx was noted. When ethanol is supplied, it is revealed that there is a positive effect on the reduction of NOx, but there is an increase in CO and exhaust gas temperature, which does not make it possible to unambiguously determine the positive effect. Additional research is required on the use of ethanol and other components as additional components to improve the environmental performance (reduce emissions) of marine diesel engines. Conclusions are drawn about the possibility of using alcohol solutions, changing the amount and time of supply of ethanol and other additional components to obtain more effective indicators.

Research of the combustion process in a tractor diesel engine when operating on alcohol and vegetable oil

BACKGROUND: Tractor diesels are widely used in agriculture, industry and transport due to their high efficiency, reliability, manufacturability and economy. Nevertheless, the ever-increasing tractor fleet is one of the main causes of environmental pollution and the increase in the consumption of petroleum motor fuel. The paper substantiates the use of an alternative fuel, suitable in its physical and chemical characteristics and properties for efficient and environmentally friendly combustion in a tractor diesel, such as ethanol and rapeseed oil.
 AIMS: Research of the combustion process in a tractor diesel engine operating on ethanol and rapeseed oil, establishment the dependencies of the influence of tractor diesel operating modes on the combustion process indicators and determination of their numerical characteristics.
 METHODS: An experimental sample of a tractor diesel engine was converted for operation on ethanol and rapeseed oil. Ethanol was used as the main fuel and was ignited with a jet of rapeseed oil entering the diesel combustion chamber. Ethanol has a lower calorific value compared to diesel fuel, therefore, there was a need to determine the optimal cyclic supply of the ignition portion of rapeseed oil and to study the indicators of the combustion process.
 RESULTS: The results of experimental studies of the effect of the use of ethanol and rapeseed oil as a pilot fuel on the indicators of the combustion process of tractor diesel are presented. The optimal value of the cyclic supply of rapeseed oil has been determined, a decrease in the value of which from the optimal value leads to an increase in exhaust gas temperature, specific effective and total fuel consumption, worsens the combustion process, while an increase of it worsens the environmental performance of a tractor diesel engine, including the smokiness of exhaust gases. The results of scientific research on the determination of optimal installation angles of advance injection of ethanol and rapeseed oil are presented.
 CONCLUSIONS: The complete replacement of petroleum diesel fuel with alternative fuels has been achieved without making significant changes to the design of a tractor diesel engine, improving its environmental characteristics while maintaining power indicators at the level of a serial diesel. On the basis of the conducted studies of the operating process of a tractor diesel engine on ethanol and rapeseed oil, the dependencies of the influence of its operating modes on the indicators of the combustion process are established and their numerical characteristics are determined.

The Effect of Ceramic Coating on Performance and Emission of Diesel Engine Operated on Diesel Fuel and Biodiesel Blends

In this work, the effect of ceramic coating on performance, exhaust gas temperature and gases emissions of diesel engine operated on diesel fuel and biodiesel blends was investigated. A conventional four stroke, direct injected, single cylinder, diesel engine was tested at constant speed and at different load conditions using diesel fuel and biodiesel blends. The inlet and exhaust valves, the head of piston and cylinder head of the engine were coated by ceramic materials. Ceramic layers were made of (210-240) μm of Al2O3 and (30-60) μm of 4NiCr5Al as a bond coat for inlet and exhaust valves and (350-400) μm of YSZ and (50-100) μm of 4NiCr5Al as a bond coat for head of piston and (280-320) μm of Sic and (40-80) μm of 4NiCr5Al as a bond coat for cylinder head. The coating technique adapted in this work is the flame spray method. The engine with valves, piston and cylinder head ceramic coated research was tested for the same operation conditions of the engine (without coating). The results showed that a reduction in brake specific fuel consumption of 19.29%, 15.91%, 14.65% and 7.06%, an increase in brake thermal efficiency of 23.68%, 19.77%, 16.51% and 6.32%, the increase in exhaust gas temperature of 9.01%, 7.22%, 15.7% and 11.42%, the reduction of CO emission of 18.57%, 20%, 20.5% and 27.77%, the reduction of HC emission of 28.97%, 43.9%, 38.88% and 36.41% for diesel, B5,B10 and B100 respectively.

Performance and emissions of a diesel engine burning blends of Jatropha and waste cooking oil biodiesel

Blending of biodiesels is a straightforward but efficient solution to the issue of improving biodiesel characteristics in cold climates. A comparison of emissions and performance of a diesel engine powered by methyl ester blends made from jatropha and waste cooking oil (WCO) was investigated. Jatropha oil was converted into biodiesel through esterification and transesterification, but WCO biodiesel was produced by transesterification. Volume percentages of WCO and jatropha biodiesels as 5, 10, 15, 20, and 100% were prepared. Peak improvements in brake thermal efficiency (BTE) were 7% and 6% for JB20 and WB10 + JB10, respectively, at 75% of engine output power over diesel fuel. Maximum reductions in brake specific fuel consumption (BSFC) related to diesel oil were for JB20 and WB10 + JB10 6 and 5%, respectively. For JB100, the maximum increase in exhaust gas temperature over diesel oil was 45%. For WB10 + JB10, the maximum reduction in carbon dioxide (CO2) emission about pure diesel was 10%. WB10 + JB10 blend had carbon monoxide (CO) emission reduction up to 6% than fossil diesel. For WB10 + JB10, the maximum reduction in nitrogen oxides (NOx) emission relative to crude diesel was 10%. WB10 + JB10 had the greatest reduction in smoke emission when compared to diesel oil as 22%. WB10 + JB10 had the largest reduction in unburned hydrocarbons (HC) of 14% over diesel oil at 75% of output power. In comparison to other fuels, the WB10 + JB10 and JB20 biodiesel blends produce better engine performance and lower emissions as compared to other biodiesel blends. As an alternative fuel in conventional diesel engines, it is recommended to use a mixture of jatropha and WCO biodiesels of 10% by volume.

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.

Application progress of small-pore zeolites in purifying NOx from motor vehicle exhaust

• Small-pore SSZ-13 and SSZ-39 zeolites have unique advantages in purifying NOx. • Pd/zeolites as PNAs present the superior low-temperature NOx adsorption activity. • Non-precious metal Co/zeolite is an ideal substitute for Pd/PNAs to reduce the cost. • Cu/zeolites possess the excellent high-temperature NH3-SCR catalytic activity. • Fe/Mn/Ce doped Cu/zeolites can broaden the NH3-SCR active temperature window. Lean-burn mode results in the high NOx emission of diesel vehicles despite its high fuel economy. NOx can be effectively removed by the SCR unit during normal operation, however, elimination during the cold start period needs to be addressed soon. Passive NOx adsorber (PNA) was proposed to adsorb and store NOx emitted during the cold start period. With the increase of exhaust gas temperature during normal operation, the adsorbed NOx will be quickly released and efficiently converted to N 2 when flowing through the downstream SCR catalyst. After years’ investigation, small-pore zeolites such as CHA and AEI have been found to possess superior hydrothermal stability and NOx selectivity compared with medium and large pore zeolites, and the former’s eight-membered ring structure effectively exclude large hydrocarbons from entering the zeolite channels, making them play a prominent role in NOx purification via both PNA and SCR units. SSZ-13 and SSZ-39 zeolites, which belong to CHA and AEI topologies respectively, has been confirmed to exhibit excellent low-temperature NOx adsorption performance and high-temperature SCR denitrification performance. In the field of purifying NOx from the diesel vehicle exhaust, the review simultaneously focused on the application of SSZ-13 and SSZ-39 zeolites in NOx purification from two aspects of PNA and SCR in recent decades. In addition, the unique advantages of their modified form of loading Pd/Co as PNAs, or loading Cu doped with Fe/Mn/Ce as SCR catalysts were systematically clarified, in order to provide some advanced guidance for the researchers in the purification of NOx from the diesel engine exhaust.

Ensuring the Environmental Friendliness of Drillships during Their Operation in Special Ecological Regions of Northern Europe

The features of the operation of the drillship-type vessels in special ecological regions of Northern Europe are considered. The main gap in the study of these systems is to determine the optimal degree of recirculation. The requirements of the International Maritime Organization for the emission of nitrogen oxides from the exhaust gases of marine diesel engines are given. The aim of the study is to determine the optimal degree of recirculation of exhaust gases of a 16V32 STX-MAN marine diesel. During the research, the optimal degree of exhaust gas recirculation varied in the range of 0–21%, the load on the diesel—in the range of 35–95% of the rated power. It was established that in this case, the emission of nitrogen oxides decreases up to 7.7–33.6%, the specific fuel consumption increases up to 0.2–3.5%. It was also found that the use of gas recirculation in the range of 18–21% at loads of 35–55% leads to a critical increase in exhaust gas temperature. It is advisable to use exhaust gas recirculation in the range of 6–15% to ensure the environmental friendliness of the operation of the drillships. In these modes, the maximum reduction in nitrogen oxide emissions is ensured with a minimum increase in specific fuel consumption. Future studies should be directed at the development of the criteria for the environmental stability of sea vessels.

Consequences of ignition timing on a hydrogen-fueled engine at various equivalence ratio

ABSTRACT The energy crisis in the transportation sector directs researchers to look for renewable alternative energy sources. Among all available, hydrogen is one of the prominent contenders that can be renewed and available on a large scale and is carbon-free. The study suggests hydrogen is a better fuel for SI engines than CI engines. However, its feasibility still needs to be investigated. In the present experimental study, a hydrogen-fueled SI engine is tested for various equivalence ratios (ϕ) and ignition timing (IT) at a compression ratio (CR) of 14:1. The outcomes show that the brake thermal efficiency (BTE) increases by 1.07% with increasing ϕ, while a slightly retarded IT exhibits the best figure. There is an average 1.42% increase per ϕ from gasoline noticed at ϕ 0.6, which increased to 2.12% at ϕ 0.8. The cylinder pressure and net heat release rate improve and advance with retarding IT and increasing ϕ. The flame development period (CA10) continuously reduces with increasing ϕ by an average 1.93%/ϕ change and retarding IT by 2.17%/2°CA ignition retard, due to increased mass of hydrogen and increased cylinder temperature. While flame propagation period (CA10-90) reduces with increasing ϕ and reduces to a minimum with retarding IT and then increase. The maximum cylinder temperature (Tmax) and exhaust gas temperature (EGT) increase with increasing ϕ by 3.28% and 3.62%, respectively, while Tmax reduces with retarding IT, resulting in a reduction in NOx emission. The EGT increases with retarding IT. The NOx emissions increase with ϕ by an average of 4.72%; however, at higher ϕ = 0.8, the NOx emissions are 2.51% lower than gasoline for most of the retarded IT. At a retarded IT, hydrogen performs similarly to gasoline at moderate NOx emissions. The high CR helps reduce volumetric losses reflected in BTE, found above gasoline despite less fuel energy supplied than gasoline. Although NOx emissions are controlled by retarding IT, an efficiently controlling IT resulted in a severe drop in BTE.

Impacts of different exhaust thermal management methods on diesel engine and SCR performance at different altitude levels

Exhaust thermal management is important for efficient operation of the diesel engine aftertreatment system to meet emissions requirements at low speed and low load conditions. In order to study the impacts of exhaust thermal management strategies on diesel engine performance and SCR conversion efficiency at different altitudes, the effects of the altitudes (2000, 1000, and 0 m), intake throttling, exhaust throttling, and post injection were experimentally studied with a high-pressure common-rail diesel engine that consisted of a diesel oxidation catalyst (DOC) and a selective catalytic reduction (SCR) aftertreatment device. The results showed that the exhaust temperature and the SCR conversion efficiency were improved by intake or exhaust throttling or post injection at any altitudes. However, the intake or exhaust throttling resulted in engine air flow rate reduction, combustion deterioration, brake specific fuel consumption (BSFC) increase, and NOx emissions decrease. When the intake throttling and the exhaust throttling were compared with the same pressure change amplitude, the intake throttling provided better effects on exhaust temperature enhancement, SCR conversion efficiency increase, while the exhaust throttling provided worse effects on BSFC. As the altitudes increased, the impacts of the intake or exhaust throttling on the SCR conversion efficiency and the BSFC became more prominent. Moreover, increasing post injection fuel quantity or retarding post injection timing made combustion worse, BSFC higher, and NOx emissions lower with benefits of exhaust gas temperature increase and SCR conversion efficiency increase. Therefore, post injection is an effective method of exhaust thermal management and should be adopted first. Then, intake throttling should be used. Finally, exhaust throttling can be considered.

Effect of hydrogen and ethanol addition in cashew nut shell liquid biodiesel operated direct injection (DI) diesel engine

In this experimental research, the hydrogen gas at a different flow rate (4 lpm, 8 lpm, & 12 lpm) is introduced into the intake port of a diesel engine fueled with B20 (20% CNSL (Cashew nut shell liquid) + 80% diesel) biodiesel blend to find out the best H2 flow rate. Then, ethanol-blended (5%, 10%, and 15% by volume) B20 blend along with the best H2 flow rate are tested in the same engine to examine the engine performance. The experimental results showed that B20 with 8 lpm H2 flow gives the maximum brake thermal efficiency and subsequently reduces the BSFC. Furthermore, by blending ethanol with the B20 blend, the BTE of the engine is improved further. The 10% ethanol blended B20 blend with 8 lpm hydrogen flow gives the maximum BTE of 37.9% higher than diesel whose values are 33.6% at full load. Also, this fuel combination led to the maximum reduced levels of CO and HC emissions with an increase in exhaust gas temperature and NOx emissions. From the results, the 10% ethanol blended B20 blend with 8 lpm H2 flow dual-fuel configuration is recommended as an alternative to sole diesel fuel.

Cyclic oxidation of high-silicon spheroidal graphite iron

In service, automotive exhaust manifolds are submitted to rapid thermal cycling up to 700–750 °C. To simulate an increase in exhaust gas temperature, a high-silicon cast iron was tested for rapid thermal cycling up to 800 °C. In addition to the well-known duplex oxide scale, rapid cyclic oxidation promotes the formation of a columnar zone at the substrate/oxide interface that has never been reported. It is evidenced that this columnar zone proceeds from a repetitive process. Based on detailed metallographic analysis using optical observations, in-situ XRD, micro-analyses and Raman spectroscopy, a mechanism explaining the formation of this columnar zone is proposed.

Thermal Performance of Compression Ignition Engine Using High Content Biodiesels: A Comparative Study with Diesel Fuel

In this study, engine performance on thermal factors for different biodiesels has been studied and compared with diesel fuel. Biodiesels were produced from Pongamia pinnata (PP), Calophyllum inophyllum (CI), waste cooking oil (WCO), and acid oil. Depending on their free fatty acid content, they were subjected to the transesterification process to produce biodiesel. The main characterizations of density, calorific range, cloud, pour, flash and fire point followed by the viscosity of obtained biodiesels were conducted and compared with mineral diesel. The characterization results presented benefits near to standard diesel fuel. Then the proposed diesel engine was analyzed using four blends of higher concentrations of B50, B65, B80, and B100 to better substitute fuel for mineral diesel. For each blend, different biodiesels were compared, and the relative best performance of the biodiesel is concluded. This diesel engine was tested in terms of BSFC (brake-specific fuel consumption), BTE (brake thermal efficiency), and EGT (exhaust gas temperature) calculated with the obtained results. The B50 blend of acid oil provided the highest BTE compared to other biodiesels at all loads while B50 blend of WCO provided the lowest BSFC compared to other biodiesels, and B50 blends of all biodiesels provided a minimum % of the increase in EGT compared to diesel.

The effect of H2O on the use of ethanol as reductant in the SCR system

In this experimental study, effects of H2O on the use of ethanol as reducing agents were investigated on the Ag-Pt-W-Ti/Cordierite catalyst. Ag-Pt-W-Ti/Cordierite catalyst was synthesized using the impregnation method for selective catalytic reduction (SCR) of NOx. To investigate the effects of H2O addition on the NOx conversion ratios, tests were carried out at 200-270 ° C under 30000 h-1 GHSV using three different reductants (ethanol, 5 %H2O - 95 %ethanol, 10 %H2O - 90 %ethanol). The catalytic activity of the catalyst increased with increase in exhaust gas temperature. The highest NOx conversion ratio was 89.9 % at 270 oC with ethanol. The tests showed that when the H2O content of the reductant increased from 5 % to 10 %, the NOx conversion ratios significantly decreased at temperatures below 240 oC. NOx conversion ratios enhanced as engine load increased.

Exhaust valve phasing controllers for cold start NOx emissions reduction in heavy duty diesel engines

In this paper, early exhaust valve opening (EVO) is applied to a diesel engine for fast warm up of the selective catalytic reduction (SCR) system with the ultimate goal of tailpipe NOx emissions reduction. By advancing EVO from top dead center, the exhaust gas temperature increases and the exhaust flow reduces, influencing the enthalpy available to warm up the SCR, and the engine-out NOx emissions increase or decrease depending on the engine’s operating conditions. Therefore, proper management of EVO is required to ensure that (1) engine-out NOx emissions do not increase when the SCR catalyst is cold; (2) heat transfer to the SCR increases and it warms up faster than the baseline operation (without EVO phasing); and (3) fuel consumption increase is minimal. A novel model predictive controller (MPC) is proposed for this application, assuming a limited preview of the drive cycle is available. For the MPC, an optimization objective function is applied such that a sequential warm up strategy can be implemented for the aftertreatment system catalysts. Using this technique, the prediction horizon for effective thermal management of the slow SCR system is reduced. In addition, a rule-based logic is offered as an alternative to the predictive controller to calculate the EVO trajectory with less computational power. Observations based on optimization problems solved by dynamic programing (DP) were used to develop the rule-based controller. Both the rule-based logic and model-based MPC are tested with a detailed high fidelity one-dimensional model in a model-in-the-loop simulator. Results indicate the potential of an EVO phasing system with the proposed controllers to reduce tailpipe NOx by 10% and 25% for the world harmonized transient cycle (WHTC) and federal test procedure (FTP), respectively. The rule-based controller has been found to be sensitive to the test drive cycle while the model based MPC shows a consistent performance, that is, independent of the test trajectory.

Correlation study of fuel injection strategies on engine emission and lubricating oil performance

Based on different fuel injection strategies, this paper analyzes the factors such as engine original emission smoke, exhaust temperature, soot content, wear spot diameter and kinematic viscosity. The study found that delaying injection timing, increased afterburn, engine original soot emissions, exhaust gas temperature increase, but will increase the thermal load of the parts. At the same time, the growth rate of lubricant soot and kinematic viscosity increased; The wear spot diameter at the same soot content is reduced, and the wear is reduced. In the end, the paper finally selects 1°CA BTDC as the optimal fuel injection strategy to achieve rapid aging of engine lubricating oil in order to complete the assessment of the anti-wear performance of lubricating oil.

Recovering waste energy of the combined gas turbine system using paraffin melting

This work covers waste energy utilization of the combined power cycle by using it in the candle raw material (paraffin) melting process and an economic study for this process. After a partial utilization of the burned fuel energy in a real bottoming steam power generation, the exhaust gas contains 0.033 of the initially burned energy. This tail energy with about 128 ºC is partly driven in the heat exchanger of the paraffin melting system. Ansys-Fluent Software was used to study the paraffin wax melting process by using a layered system that utilizes an increased interface area between the heat transfer fluid (HTF) and the phase change material (PCM) to improve the paraffin melting process. The results indicate that using 47.35 kg/s, which is 5% of the entire exhaust gas (881.33 kg/s) from the exit of the combined power cycle, would be enough for producing 1100 tons per month, which corresponds to the production quantity by real candle's factories. Also, 63% of the LPG cost will be saved, and the payback period of the melting system is 2.4 years. Moreover, as the exhaust gas temperature increases, the consumed power and the payback period will decrease.

Thermodynamic Modeling of a Turbocharged Diesel–Hydrogen Dual-Fuel Marine Engine

In this work, a thermodynamic model is used to analyze the influence of some usual engine parameters such as compression ratio, ambient temperature, turbocharger compressor pressure ratio, equivalence ratio, and engine speed on the performances of a diesel–hydrogen dual-fuel marine engine. The model takes into consideration the change in the composition of the working fluid resulting from the combustion cycle as well as the reactive mixture. This model considers also the dependence of the working fluid specific heat on temperature. Results show that the increase in the equivalence ratio yields to an improvement of the brake specific fuel consumption, the brake power output, the brake thermal, and exergy efficiencies with an increase in the exhaust gas temperature. Nevertheless, it produces a drop in volumetric efficiency. The engine speed has a slight effect on the brake thermal efficiency, exergy efficiency, and the brake specific fuel consumption. The engine speed affects the engine power output mainly at higher values of the fuel–air equivalence ratio due to the reduction in heat losses and the fuel energy consumed by the engine. The increase in the turbo-compressor pressure ratio has a significant effect on the improvement of engine performance. However, it has an insignificant effect on the exhaust gas temperature. The exergy destroyed in the engine dominates. It accounts for 88.2% of the total exergy destroyed in the overall system. The remaining components (turbo-compressor, intercooler, mixer, catalytic converter, and turbine) are responsible for only 11.2%.

The research on the influence of boiler operating parameters on thermal efficiency

The influence of operating parameters on thermal efficiency was analyzed by thermal balance experiment of the boiler. The mathematical model of thermal efficiency was obtained by thermal balance equation. The results showed that the thermal efficiency decreased with the increase of exhaust gas temperature. The excess air coefficient had an important effect on thermal efficiency of the boiler. The thermal efficiency decreased with the increase of excess air coefficient. The increase of inlet air temperature leaded to the increase of thermal efficiency when other operating parameters remained unchanged. The thermal efficiency increased with the increase of fuel calorific value. As a result, in order to improve thermal efficiency, the optimum excess air coefficient should be adjusted as much as possible to ensure combustion condition of the boiler. For running boiler, the economizer should be installed on heated surface at the end of boiler.