Fuel-Composition Effects on High-Temperature Corrosion in Industrial/Commercial Boilers and Furnaces: A Review

1985 ◽  
Vol 107 (3) ◽  
pp. 744-757 ◽  
Author(s):  
J. Bellan ◽  
S. Elghobashi
Keyword(s):  
Metal Surfaces ◽  
Review Literature ◽  
Operating Conditions ◽  
Fuel Oil ◽  
Batch Distillation ◽  
Liquid Form ◽  
Combustion Gases ◽  
Initial Fuel ◽  
Trace Compounds ◽  
Ignition And Combustion

In this review, literature relevant to the problems of deposits and corrosion in industrial/commercial furnaces and boilers is analyzed, and the facts are synthesized into a picture that addresses corrosion problems expected with the use of unconventional fuels. Corrosion is found to depend greatly on the phenomena occurring during the combustion of fuel-oil sprays introduced into the furnace. In a first step, the drops that form the spray heat up and evaporate in a way that closely resembles a batch distillation process. Eventually, ignition and combustion occur with the subsequent change of the liquid fuel drops into carbonaceous, porous, sphere-like particles called cenospheres. In a second step, these cenospheres burn and the products of this combustion step determine the majority of the deposits on metal surfaces. This observation is very important since nonvolatile, non-combustible, corrosive trace compounds existing in the initial fuel-oil drop will have a much higher concentration in the cenosphere than in the original fuel. Accordingly, it is recommended that the theoretical and experimental study of oil spray combustion, cenosphere formation, and cenosphere combustion in a cloud of cenospheres receive a very high priority. Corrosion by gases is found to be unimportant. Deposits are found to be much more corrosive when in liquid form, although corrosion by solid deposits is by no means negligible. As a result, it is suggested in the study that corrosion on highly polished metal surfaces should be studied in order to evaluate the potential of this method of inhibiting deposition and thus hindering corrosion. Recent advances in the theory of deposition from combustion gases are also outlined in this study. The literature survey shows that the main corrosion-causing fuel constituents present in unconventional fuels are sulfur, alkali, vanadium, carbon and carbon monoxide, iron, and chloride. It is found that sometimes one of these compounds might act as a catalyst in corrosive reactions initiated by another compound, and therefore great care must be taken to identify the corrosion-causing compound in the deposits on metal surfaces. It is also found that in some cases a corrosive compound will inhibit the corrosive action of another corrosive compound. It is recommended that such situations be studied further so as to investigate the possibility of an optimum concentration of two such corrosive compounds that would minimize metal wastage. The problem of performing meaningful corrosion experiments is also addressed in this report and specific recommendations are made to achieve this goal. Finally, the effects of additives and the furnace operating conditions are discussed, and potential problems with both additives and new operating conditions are mentioned. The recommendations at the end of this study present a comprehensive set of areas to be investigated in order to better understand and be able to mitigate corrosion problems associated with unconventional fuels. High-priority experimental and theoretical studies are also outlined.

Coverage and Stability of NHx Terminated Cobalt and Ruthenium Surfaces: a First Principles Investigation

2019 ◽  
Author(s):  
Ji Liu ◽  
Michael Nolan
Keyword(s):  
Metal Surfaces ◽  
High Vacuum ◽  
Atomic Layer ◽  
Nitrogen Plasma ◽  
Operating Conditions ◽  
Ultra High Vacuum ◽  
Bridge Site ◽  
Stable Surface ◽  
Saturation Coverage ◽  
The Stability

<div>In the atomic layer deposition (ALD) of Cobalt (Co) and Ruthenium (Ru) metal using nitrogen plasma, the structure and composition of the post N-plasma NHx terminated (x = 1 or 2) metal surfaces are not well known but are important in the subsequent metal containing pulse. In this paper, we use the low-index (001) and (100) surfaces of Co and Ru as models of the metal polycrystalline thin films. The (001) surface with a hexagonal surface structure is the most stable surface and the (100) surface with a zigzag structure is the least stable surface but has high reactivity. We investigate the stability of NH and NH2 terminations on these surfaces to determine the saturation coverage of NHx on Co and Ru. NH is most stable in the hollow hcp site on (001) surface and the bridge site on the (100) surface, while NH2 prefers the bridge site on both (001) and (100) surfaces. The differential energy is calculated to find the saturation coverage of NH and NH2. We also present results on mixed NH/NH2-terminations. The results are analyzed by thermodynamics using Gibbs free energies (ΔG) to reveal temperature effects on the stability of NH and NH2 terminations. Ultra-high vacuum (UHV) and standard ALD</div><div>operating conditions are considered. Under typical ALD operating conditions we find that the most stable NHx terminated metal surfaces are 1 ML NH on Ru (001) surface (350K-550K), 5/9 ML NH on Co (001) surface (400K-650K) and a mixture of NH and NH2 on both Ru (100) and Co (100) surfaces.</div>

scholarly journals Oxidative Extractive Desulfurization System for Fuel Oil Using Acidic Eutectic-Based Ionic Liquid

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1050
Author(s):  
Sarrthesvaarni Rajasuriyan ◽  
Hayyiratul Fatimah Mohd Zaid ◽  
Mohd Faridzuan Majid ◽  
Raihan Mahirah Ramli ◽  
Khairulazhar Jumbri ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Removal Efficiency ◽  
Environmental Effects ◽  
Sulfur Compounds ◽  
Operating Conditions ◽  
Fuel Oil ◽  
Organosulfur Compounds ◽  
Dsc Analysis ◽  
Oil Refineries ◽  
Desulfurization Process

The biggest challenge faced in oil refineries is the removal of sulfur compounds in fuel oil. The sulfur compounds which are found in fuel oil such as gasoline and diesel, react with oxygen in the atmosphere to produce sulfur oxide (SOx) gases when combusted. These sulfur compounds produced from the reaction with oxygen in the atmosphere may result in various health problems and environmental effects. Hydrodesulfurization (HDS) is the conventional process used to remove sulfur compounds from fuel oil. However, the high operating conditions required for this process and its inefficiency in removing the organosulfur compounds turn to be the major drawbacks of this system. Researchers have also studied several alternatives to remove sulfur from fuel oil. The use of ionic liquids (ILs) has also drawn the interest of researchers to incorporate them in the desulfurization process. The environmental effects resulting from the use of these ILs can be eliminated using eutectic-based ionic liquids (EILs), which are known as greener solvents. In this research, a combination of extractive desulfurization (EDS) and oxidative desulfurization (ODS) using a photocatalyst and EIL was studied. The photocatalyst used is a pre-reported catalyst, Cu-Fe/TiO2 and the EIL were synthesized by mixing choline chloride (ChCl) with organic acids. The acids used for the EILs were propionic acid (PA) and p-toluenesulfonic acid (TSA). The EILs synthesized were characterized using thermogravimetry analyser (TGA) differential scanning calorimetry (DSC) analysis to determine the physical properties of the EILs. Based on the TGA analysis, ChCl (1): PA (3) obtained the highest thermal stability whereas, as for the DSC analysis, all synthesized EILs have a lower melting point than its pure component. Further evaluation on the best EIL for the desulfurization process was carried out in a photo-reactor under UV light in the presence of Cu-Fe/TiO2 photocatalyst and hydrogen peroxide (H2O2). Once the oxidation and extraction process were completed, the oil phase of the mixture was analyzed using high performance liquid chromatography (HPLC) to measure the sulfur removal efficiency. In terms of the desulfurization efficiency, the EIL of ChCl (1): TSA (2) showed a removal efficiency of about 99.07%.

Optimization of the operating conditions of fuel oil combustion in the furnaces of large-capacity boilers

2007 ◽  
Vol 54 (6) ◽  
pp. 444-448 ◽  
Author(s):  
N. A. Zroichikov ◽  
M. G. Lyskov ◽  
V. B. Prokhorov ◽  
E. A. Morozova
Keyword(s):  
Operating Conditions ◽  
Fuel Oil ◽  
Large Capacity

Hydrodynamic and Thermal Characteristics of the Flow Inside a Rectangular Microchannel With Different Cylindrical Micro Pin Fins

2016 ◽  
Author(s):  
Ali Mohammadi ◽  
Ali Koşar
Keyword(s):  
Computational Study ◽  
Thermal Characteristics ◽  
3D Models ◽  
Operating Conditions ◽  
Bottom Surface ◽  
Liquid Form ◽  
Rectangular Microchannel ◽  
Pin Fin ◽  
Pin Fins ◽  
Micro Pin Fins

This article presents a computational study to investigate the hydrodynamic and thermal characteristics of the flow inside a rectangular microchannel with the dimensions of 5000 × 1500 × 100 μm3 (l × w × h’) with different inline arrangements of cylindrical micro pin fins. A parametric study is performed on the effect of different geometrical specifications of micro pin fins on the wake-pin fin interaction. Three values of (50, 100 and 200 μm) are considered for the pin fin diameters (D) while the overall height (H) of the system is set to be constant (100 μm). For the first two cases, two longitudinal and vertical pitch ratios (SL/D and ST/D) of 1.5 and 3 are considered while for H/D ratio of 0.5, only ST/D ratio of 1.5 and SL/D ratios of 1.5 and 3 are considered. As a result, a total number of ten different geometries are analyzed in five different Reynolds numbers of 20, 40, 80, 120 and 160. A constant heat flux is applied through the bottom surface of the microchannel as well as the micro pin fins surfaces. All other surfaces are assumed to be thermally isolated. Thermodynamic properties of water are set to vary with temperature and it is assumed that the working flow remains in the liquid form in all operating conditions. ANSYS commercial package v14.5 with an academic license is utilized to generate the 3D models, applying the appropriate grid networks and simulating the flow fields for each configuration. Results show major dependencies of pressure drops, friction factors, Nusselt numbers and Thermal Performance Index values on ST/D ratio and Reynolds number while minor dependencies of these parameters on SL/D and H/D ratios are observed.

Numerical and Experimental Analysis of Ignition and Combustion Stability in EGR Dilute GDI Operation

2014 ◽  
Author(s):  
Riccardo Scarcelli ◽  
Nicholas S. Matthias ◽  
Thomas Wallner
Keyword(s):  
Flame Propagation ◽  
Numerical Results ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Ignition Process ◽  
Ignition System ◽  
Cyclic Variability ◽  
Beneficial Effects ◽  
Engine Testing ◽  
Ignition And Combustion

This paper discusses the characteristics of EGR dilute GDI engines in terms of combustion stability. A combined approach consisting of RANS numerical simulations integrated with experimental engine testing is used to analyze the effect of the ignition source on flame propagation under dilute operating conditions. A programmable spark-based ignition system is compared to a production spark system in terms of cyclic variability and ultimately indicated efficiency. 3D-CFD simulations are carried out for multiple cycles with the goal of establishing correlations between the characteristics of the ignition system and flame propagation as well as cycle-to-cycle variations. Numerical results are compared to engine data in terms of in-cylinder pressure traces. The results show that an improved control over the energy released to the fluid surrounding the spark domain during the ignition process has beneficial effects on combustion stability. This allows extending the dilution tolerance for fuel/air mixtures. Although affected by cyclic variability, numerical results show good qualitative agreement with experimental data. The result is a simple but promising approach for relatively quick assessment of stability improvements from advanced and alternative ignition strategies.

Modeling and Performance Analysis of Combined-Cycle Based Ship Power Plant

2010 ◽  
Vol 44-47 ◽  
pp. 1240-1245 ◽  
Author(s):  
Hong Zeng ◽  
Xiao Ling Zhao ◽  
Jun Dong Zhang
Keyword(s):  
Diesel Engine ◽  
Power Plant ◽  
Performance Analysis ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Fuel Oil ◽  
Plant Performance ◽  
Oil Consumption ◽  
Combined Cycle Power Plant ◽  
Simulation Performance

For combined-cycle power plant performance analysis, a ship power plant mathematical model is developed, including diesel engine, controllable pitch propeller, exhaust gas boiler, turbine generator and shaft generator models. The simulation performance characteristic curves of diesel engine under various loads are given. Comparison of simulation results and experimental data shows the model can well predict the performance of diesel engine in various operating conditions. The specific fuel oil consumption contours of combined-cycle power plant and the relations between engine operating conditions and steam cycle parameters are given. The influence of diesel engine operating conditions to the overall performance of combined-cycle power plant is discussed.

Numerical and Experimental Investigations on Liner Heat Transfer in an Aero Engine Combustion Chamber

2017 ◽  
Author(s):  
Korukonda Venkata Lakshmi Narayana Rao ◽  
B. V. S. S. S. Prasad ◽  
Ch. Kanna Babu ◽  
Girish K. Degaonkar
Keyword(s):  
Combustion Chamber ◽  
Structural Integrity ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Numerical Computations ◽  
Combustion Gases ◽  
Flow Characterization ◽  
Aero Engine ◽  
Straight Flow ◽  
Flow Variables

The Gas turbine combustion chamber is the highest thermally loaded component where the temperature of the combustion gases is higher than the melting point of the liner that confines the gases. Combustor liner temperatures have to be evaluated at all the operating conditions in the operating envelope to ensure a satisfactory liner life and structural integrity. On experimental side the combustion chamber rig testing involves a lot of time and is very expensive, while the numerical computations and simulations has to be validated with the experimental results. This paper is mainly based on the work carried out in validating the liner temperatures of a straight flow annular combustion chamber for an aero engine application. Limited experiments have been carried out by measuring the liner wall temperatures using k-type thermocouples along the liner axial length. The experiments on the combustion chamber testing are carried out at the engine level testing. The liner temperature which is numerically computed by CHT investigations using CFX code is verified with the experimental data. This helped in better understanding the flow characterization around and along the liner wall. The main flow variables used are the mass flow rate, temperature and the pressure at the combustor inlet. Initially, the fuel air ratio is used accordingly to maintain the same T4/T3 ratio. The effect of liner temperature with T3 is studied. Since T4 is constant, the liner temperature is only dependent on T3 and follows a specific temperature distribution for the given combustor geometry. Hence this approach will be very useful in estimating the liner temperatures at any given T3 for a given combustor geometry. Further the liner temperature is also estimated at other fuel air ratios (different T4/T3 ratios) by using the verified CHT numerical computations and found that TL/T3 remains almost constant for any air fuel ratio that is encountered in the operating envelope of the aero engine.

Ignition of Diesel Pilot Fuel in Dual-Fuel Engines

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Marcus Grochowina ◽  
Daniel Hertel ◽  
Simon Tartsch ◽  
Thomas Sattelmayer
Keyword(s):  
High Speed ◽  
Measurement Techniques ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Dual Fuel ◽  
Spray Formation ◽  
Fuel Concentration ◽  
Injection Parameters ◽  
Pilot Fuel ◽  
Ignition And Combustion

Dual-fuel (DF) engines offer great fuel flexibility combined with low emissions in gas mode. The main source of energy in this mode is provided by gaseous fuel, while the diesel fuel acts only as an ignition source. For this reason, the reliable autoignition of the pilot fuel is of utmost importance for combustion in DF engines. However, the autoignition of the pilot fuel suffers from low compression temperatures caused by Miller valve timings. These valve timings are applied to increase efficiency and reduce nitrogen oxide (NOx) emissions. Previous studies have investigated the influence of injection parameters and operating conditions on ignition and combustion in DF engines using a unique periodically chargeable combustion cell. Direct light high-speed images and pressure traces clearly revealed the effects of injection parameters and operating conditions on ignition and combustion. However, these measurement techniques are only capable of observing processes after ignition. In order to overcome this drawback, a high-speed shadowgraph technique was applied in this study to examine the processes prior to ignition. Measurements were conducted to investigate the influence of compression temperature and injection pressure on spray formation and ignition. Results showed that the autoignition of diesel pilot fuel strongly depends on the fuel concentration within the spray. The high-speed shadowgraph images revealed that in the case of very low fuel concentration within the pilot spray, only the first stage of the two-stage ignition occurs. This leads to large cycle-to-cycle variations and misfiring. However, it was found that a reduced number of injection holes counteract these effects. The comparison of a diesel injector with ten-holes and a modified injector with five-holes showed shorter ignition delays, more stable ignition and a higher number of ignited sprays on a percentage basis for the five-hole nozzle.

scholarly journals Optimization of Bio-oil Production from Empty Palm Fruit Bunches by Pyrolysis using Response Surface Methodology

REAKTOR ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 1-9
Author(s):  
Tutuk Djoko Kusworo ◽  
Bayu Aji Pratama ◽  
Dhea Putri Safira
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Optimal Operation ◽  
Operating Conditions ◽  
Fuel Oil ◽  
Oil Yield ◽  
Human Populations ◽  
Operation Condition ◽  
Palm Fruit ◽  
Bio Oil

The need for fuel oil continues to increase in line with the increasing number of human populations and the growth rate of dependence on fuel oil. Bio-oil is a condensed-liquid mixture that results from the thermal derivation of biomass containing hemicellulose, lignin, and cellulose. This research developed an optimization of the operation condition of bio-oil from empty palm fruit bunches (OPEFB) using a modified pyrolysis reactor. The temperature and mass of empty palm fruit bunches were the two parameters considered in this study. Optimization was carried out on process parameters using the surface response methodology (RSM) and variance analysis (ANOVA). The significance of the different parameters and the effect of the relationship between parameters on the bio-oil yield is determined using a full factorial central composite design. The optimal operation condition of pyrolysis was found to be 570.71 oC, and the mass of empty palm fruit bunch 420.71 gr. Predictions from the optimum variable of operating conditions produce a bio-oil yield of 5.58%. The actual bio-oil yield on the optimum condition that was be validated is 5.6 %. The chemical composition of bio-oil obtained was evaluated by GCMS to ensure its characterization as a fuel.Keywords: Empty palm fruit bunches, Bio-oil, Pyrolysis, Response Surface Methodology, Optimization

Utilization of Tea Tree Branches as a Source of Thermal Energy

2020 ◽  
Vol 849 ◽  
pp. 8-13
Author(s):  
Rudi Firyanto ◽  
Heru Susanto ◽  
Retno S.L. Ambarwati ◽  
Suherman ◽  
Widayat
Keyword(s):  
Thermal Energy ◽  
Scale Up ◽  
Operating Conditions ◽  
Fuel Oil ◽  
Optimum Operating ◽  
Large Contribution ◽  
Drying Process ◽  
Processing Industry ◽  
Tea Plantations ◽  
Gasification Technology

Energy has an important role in the survival of the tea processing industry. The costs for energy generation and application have a large contribution to the total cost of the tea processing. The use of fuel oil and electricity, especially in the drying process is the biggest energy user stage. In line with the development of Indonesia's tea processing industry, it is felt necessary to immediately utilize the source of biomass in tea plantations through the application of gasification technology. The development of tea processing in the future should pay more attention to aspects of energy and the environment as the main discussion. This study aims to examine the development of gasification technology in converting biomass as thermal energy to meet gas quality in the tea drying process. The hypothesis is that through the gasification biomass technology of tea plantations, will produce gas as thermal energy that meets the quality of the tea drying process. The target to be achieved is in the form of laboratory technical data for the design, operation of the process, scale-up and evaluation of the performance of the gasifier which includes flame propagation, simulation of combustion and optimum operating conditions with temperature process variables, air flow rate and gas products, tea biomass capacity, and the length of the gasification process.

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