Formation of Deposits From Heavy Fuel Oil Ash in an Accelerated Deposition Facility at Temperatures Up to 1206°C

2017 ◽  
Author(s):  
Robert G. Laycock ◽  
Thomas H. Fletcher
Keyword(s):  
Gas Turbines ◽  
Gas Flow ◽  
Particle Diameter ◽  
Capture Efficiency ◽  
Fuel Oil ◽  
Nickel Base Superalloy ◽  
Gas Temperature ◽  
Heavy Fuel Oil ◽  
Hot Gas ◽  
Exhaust Stream

Some industrial gas turbines are currently being fired directly using heavy fuel oil, which contains a small percentage of inorganic material that can lead to fouling and corrosion of turbine components. Deposits of heavy fuel oil ash were created in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University under gas turbine-related conditions. Ash was produced by burning heavy fuel oil in a downward-fired combustor and collecting the ash from the exhaust stream. The mass mean ash particle diameter from these tests was 33 microns. This ash was then introduced into the TADF and entrained in a hot gas flow that varied from 1088 to 1206°C. The gas and particle velocity was accelerated to over 200 m/s in these tests. This particle-laden hot gas stream then impinged on a nickel base superalloy metal coupon approximately 3 cm in diameter, and an ash deposit formed on the coupon. Sulfur dioxide was introduced to the system to achieve 1.1 mol% SO2 in the exhaust stream in order to simulate SO2 levels in turbines currently burning heavy fuel oil. The ash deposits were collected, and the capture efficiency, surface roughness, and deposit composition were measured. The deposits were then washed with deionized water, dried, and underwent the same analysis. It was found that, as the gas temperature increased, there was no effect on capture efficiency and the post-wash roughness of the samples decreased. Washing aided in the removal of sulfur, magnesium, potassium, and calcium.

Assessing of Hot Gas Parts Using Advanced Eddy Current Testing Methods

2008 ◽  
Author(s):  
Matthias Jungbluth ◽  
Vinay Jonnalagadda ◽  
Erwan Baleine ◽  
Mattias Broddega˚rd ◽  
Rolf Wilkenho¨ner ◽  
...  
Keyword(s):  
Eddy Current ◽  
Gas Turbines ◽  
Thermal Protection ◽  
Protective Coatings ◽  
Turbine Blades ◽  
Diagnostic Methods ◽  
Design Parameters ◽  
Gas Temperature ◽  
Diagnostic Measures ◽  
Hot Gas

The turbine section of state-of-the-art industrial gas turbines is exposed to the most severe conditions such as high temperatures, corrosive environments and high mechanical stresses for several tens of thousands of hours. To withstand these conditions, turbine blades and vanes have become the most sophisticated parts. This, together with advanced manufacturing technologies, strict quality requirements and maximum reliability demands, affects costs. Different design features have been realized in the past to meet the ambitious requirements, and are also under constant development. Blades and vanes made of superalloys with directionally-solidified or single-crystal structure are used to provide highest strengths at temperatures as near as possible to the hot gas temperature. The high integrity and conformity of the parts are required to realize the material potential. Different advanced diagnostic methods are applied to ensure these over time. Another way to increase the operating temperatures of gas turbines is the application of corrosion and thermal protection coatings for one or several rows of the blades and vanes. Deviations in the specified coating thickness tend to reduce the lifetime of such coatings significantly. Hence, the monitoring of this property during the manufacturing requires special nondestructive diagnostic measures. Service exposed parts, which need to be refurbished when the protective coatings are spent, offer a significant operation potential after refurbishment. To guarantee the design parameters during the next service interval, several nondestructive material evaluation methods are available for the necessary part property assessment. Multifrequency Eddy Current has proven itself as an appropriate NDE technique to accomplish the above diagnostic requirements. The paper will give an overview of results gained at Siemens with model based Eddy Current methods using measurement systems developed by Jentek Sensors Inc., USA, and CESI, Italy. Potential applications and limitations of the method also will be discussed.

Conjugate Simulation of the Effects of Oxide Formation in Effusion Cooling Holes on Cooling Effectiveness

2009 ◽  
Author(s):  
Dieter Bohn ◽  
Robert Krewinkel
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
Gas Flow ◽  
Combined Cycle ◽  
Reference Case ◽  
Flow Area ◽  
Cooling Effectiveness ◽  
Hot Gas ◽  
Barrier Coating ◽  
Cooling Hole

Within Collaborative Research Center 561 “Thermally Highly Loaded, Porous and Cooled Multi-Layer Systems for Combined Cycle Power Plants” at RWTH Aachen University an effusion-cooled multi-layer plate configuration with seven staggered effusion cooling holes is investigated numerically by application of a 3-D in-house fluid flow and heat transfer solver, CHTflow. The effusion-cooling is realized by finest drilled holes with a diameter of 0.2 mm that are shaped in the region of the thermal barrier coating. Oxidation studies within SFB 561 have shown that a corrosion layer of several oxides with a thickness of appoximately 20μm grows from the CMSX-4 substrate into the cooling hole. The goal of this work is to investigate the effect this has on the cooling effectiveness, which has to be quantified prior to application of this novel cooling technology in real gas turbines. In order to do this, the influence on the aerodynamics of the flow in the hole, on the hot gas flow and the cooling effectiveness on the surface and in the substrate layer are discussed. The adverse effects of corrosion on the mechanical strength are not a part of this study. A hot gas Mach-number of 0.25 and blowing ratios of approximately 0.28 and 0.48 are considered. The numerical grid contains the coolant supply (plenum), the solid body for the conjugate calculations and the main flow area on the plate. It is shown that the oxidation layer does significantly affect the flow field in the cooling holes and on the plate, but the cooling effectiveness differs only slightly from the reference case. This seems to justify modelling the holes without taking account of the oxidation.

Use of Chromium Containing Fuel Additive to Reduce High Temperature Corrosion of Hot Section Parts

2000 ◽  
Author(s):  
Jean-Pierre Stalder ◽  
Peter A. Huber
Keyword(s):  
High Temperature ◽  
Hot Corrosion ◽  
Gas Turbines ◽  
High Temperature Corrosion ◽  
Fuel Oil ◽  
Fuel Additive ◽  
Fuel Quality ◽  
Common Belief ◽  
Heavy Fuel Oil ◽  
Fuel Treatment

The use of “clean” fuel is a prerequisite at today’s elevated gas turbine firing temperature, modern engines are more sensitive to high temperature corrosion if there are impurities present in the fuel and/or in the combustion air. It is a common belief that distillate grade fuels are contaminant-free, which is often not true. Frequently operators burning distillates ignore the fuel quality as a possible source of difficulties. This matter being also of concern in plants mainly operated on natural gas and where distillate fuel oil is the back-up fuel. Distillates may contain water, dirt and often trace metals such as sodium, vanadium and lead which can cause severe damages to the gas turbines. Sodium being very often introduced through contamination with seawater during the fuel storage and delivery chain to the plant, and in combination, or with air borne salt ingested by the combustion air. Excursions of sodium in treated crude or heavy fuel oil can occur during unnoticed malfunctions of the fuel treatment plant, when changing the heavy fuel provenience without centrifuge adjustment, or by inadequate fuel handling. For burning heavy fuel, treatment with oil-soluble magnesium fuel additive is state of the art to inhibit hot corrosion caused by vanadium. Air borne salts, sodium, potassium and lead contaminated distillates, gaseous fuels, washed and unwashed crude and residual oil can not be handled by simple magnesium based additives. The addition of elements like silicon and/or chromium is highly effective in reducing turbine blade hot corrosion and hot section fouling. This paper describes field experience with the use of chromium containing fuel additive to reduce high temperature corrosion of hot section parts, as well as the interaction of oil-soluble chromium and magnesium-chromium additives on material behaviour of blades and vanes, and their economical and environmental aspects.

IGNITION CONDITIONS OF A SINGLE BORON PARTICLE IN HOT GAS FLOW

2020 ◽  
Author(s):  
G. V. Ermolaev ◽  
◽  
A. V. Zaitsev ◽  
Keyword(s):  
Oxygen Concentration ◽  
Gas Flow ◽  
Flame Temperature ◽  
Combustion Process ◽  
Experimental Studies ◽  
Gas Temperature ◽  
Hot Gas ◽  
Combustion Models ◽  
Boron Particle ◽  
Boron Particles

The basic experimental studies on boron combustion are done with the same general scheme of the experiment. Boron particles are injected into flat-flame burner products with the help of the transporting jet of cold nitrogen. Boron particle combustion process is registered with a number of optical methods. It is proposed that boron particle is injected into the main hot gas flow instantly, combustion takes place at the flame temperature and predefined oxygen concentration, and the influence of the transporting cold nitrogen jet is ignored. Recent combustion models are based mostly on this type of experiments and characterized with high complexity and low prediction level. In our study, we reconstruct the particle injection conditions for several basic experimental papers. It is shown that in all experimental setups, ignition, combustion, and even total particle burnout take place in the wake of the cold nitrogen jet. This zone is characterized with a much lower gas temperature and oxygen concentration than the main flat burner flow. The total temperature decrease can be about several hundred degrees, oxygen concentration can be 30%-50% lower than that used in the previous analysis of the experimental results. The temperatures of ignition and transition to the second stage of combustion are found with the help of the test particle trajectory and temperature tracking. It is shown that analysis of the influence of boron particles injection on gas temperature and oxygen concentration is mandatory for the development of future combustion models.

Numerical Study of Conduction and Convection Between Immersed Object and Gas Fluidized Bed

Volume 1 ◽  
2004 ◽  
Author(s):  
W. M. Gao ◽  
L. X. Kong ◽  
P. D. Hodgson ◽  
B. Wang
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Solid Phase ◽  
Numerical Study ◽  
Particle Diameter ◽  
Conductive Heat ◽  
Gas Temperature ◽  
Transfer Coefficients ◽  
Immersed Surfaces ◽  
Particle Layer

To analyze the heat transfer mechanism between fluidised beds and surfaces of an immersed object, the heat transfer and gas flow was numerically simulated for different particle systems based on a double particle-layer and porous medium model. It is fund that the conductive heat transfer occurs in the stifling regions between particle and the immersed surface, which have different temperature. The diameter of the circular conduction region, dc, is a function of particle diameter, dp, and can be given by dc/dp = 0.245dp−0.3. In other areas, the heat transfer between the dense gas-solid phase and the immersed object surface is dominated by convection from the moving gas in the tunnel formed by the first-layer particles and the immersed surfaces. The average dimensionless gas velocity, εmfU/Umf, in the tunnel is a constant of about 4.6. The virtual gas temperature at the free stream conditions can be given by the surface temperature of the first-layer particles. The heat transfer coefficient on the conductive region is about 6∼10 times of that on the convection region. The Nusselt numbers for calculating the instantaneous conductive and convective heat-transfer coefficients were theoretically analysed respectively.

Turbine Off-Line Water Wash Optimization Approach for Power Generation

2006 ◽  
Author(s):  
Ahmed A. Basendwah ◽  
P. Pilidis ◽  
Y. G. Li
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Fuel Oil ◽  
Optimization Approach ◽  
Ash Deposition ◽  
Heavy Fuel Oil ◽  
Technical Problems ◽  
Water Washing ◽  
The Cost ◽  
Gains And Losses

Utility Gas turbine users are keen to use crude and heavy fuel oil as their prime operating fuels if they meet environmental regulations and are economically feasible. Fouling, or ash deposition, is one of the associated technical problems with burning such fuels. This paper intended to present new off-line water washing optimization approach for simple cycle gas turbines. In this approach, increased costs due to power loss and increased fuel consumption due to turbine fouling are analyzed. Gains and losses resulting from shutdown due to turbine washing and the cost of cleaning materials are estimated. These losses are compared with that of a clean engine to find the optimal turbine off-line water washing interval. A model gas turbine similar to the GE MS7001 EA has been built for the current study. Turbine fouling simulation and fouling detection have been determined by Cranfield University TURBOMATCH/PYTHIA software. The optimum washing interval for the datum engine is found to be once every fifteen continuous operating days. The effect of changing the washing frequency is shown on financial terms.

Design and Analysis of a Real-Time Hot Gas Temperature Estimator for Heavy-Duty Gas Turbines

2015 ◽  
Author(s):  
Eric A. Müller ◽  
Adrian Ticǎ
Keyword(s):  
Real Time ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Gas Temperature ◽  
Heavy Duty ◽  
Component Level ◽  
Load Range ◽  
Hot Gas ◽  
Dynamic Tracking ◽  
Heavy Duty Gas Turbine

The knowledge about a relevant process and lifetime indicative quantity, such as the hot gas temperature, is crucial for the control of a gas turbine. Since this indicative process quantity usually cannot be directly measured, it has to be estimated. The paper describes a model-based method to accurately estimate in real-time the hot gas temperature of a heavy-duty gas turbine. The method follows a well-balanced trade-off between resulting prediction accuracy and involved computational complexity. It takes advantage of the capability of a component-level dynamic model to predict the system behaviour and of the capacity of a dynamic tracking filter to adapt to the current gas turbine conditions. In a simulation study, it is shown that the proposed design can provide an accurate hot gas temperature estimation over the entire gas turbine load range, along the gas turbine lifecycle, and during fast transient manoeuvres.

The Development and First Commercial Application of an Innovative Diesel Engine Based Cogeneration System

1992 ◽  
Vol 206 (3) ◽  
pp. 197-207 ◽  
Author(s):  
F Nash
Keyword(s):  
Gas Turbines ◽  
Combustion Engine ◽  
Diesel Oil ◽  
Fuel Oil ◽  
Commercial Application ◽  
Exhaust Gas ◽  
Heavy Fuel Oil ◽  
Engine Exhaust ◽  
Initial Development ◽  
Cogeneration System

This paper covers the development of a cogeneration (combined heat and power) system based upon a compression ignition, reciprocating, internal combustion engine and a standard three-pass economic shell-and-tube industrial boiler as well as the first commercial application of the system. An innovative feature of this cogeneration system is that additional fuel is burnt to utilize the free oxygen in the engine exhaust gas (a practice common with gas turbines but rarely attempted with reciprocating engines) to provide a significant, fuel-efficient and easily variable increase in the high-quality heat, that is steam, output from the system. The initial development work was done in 1983 using heavy fuel oil as the fuel to both engine and burner, while the first commercial application in 1988 utilizes a dual-fuel engine (gas and diesel oil pilot or diesel oil) and dual firing of the exhaust gas duct burner with gas or diesel oil.

A Combustion Study of Gas Turbines Using Multi-Species/Reacting Computational Fluid Dynamic

2002 ◽  
Author(s):  
Sasan Armand ◽  
Mei Chen
Keyword(s):  
Carbon Monoxide ◽  
Gas Turbine ◽  
Environmental Contamination ◽  
Gas Turbines ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Combustion Products ◽  
Contamination Level ◽  
Short Term ◽  
Hot Gas

A multi-species/reacting combustion study was performed. The focus of the study was to quantify the effects of variation in air extraction and power rates on flame/outlet temperatures of a General Electric (GE), Frame 5 gas turbine. The environmental contamination level due to generation of carbon monoxide was also reported. GE, Frame 5 gas turbine has been widely used around the world for power generation, and as mechanical drives. The combustion products were examined throughout a range of air extraction rates, upon which it was determined that the combustion liners were susceptible to damage at air extraction rates above 10%, and the environmental contamination level due to carbon monoxide was increased. Furthermore, the gas flow exiting the combustion liner became non-homogeneous (i.e. a pocket of relatively hot gas formed in the middle of the flow path), which would cause damage to the downstream components. In conclusion, the short-term monetary gains from using compressed air from a gas turbine do not justify the costs of down time for repairs and the replacement of expensive hot-gas-path components.

Studies on Coal Ignition and Combustion Characteristics

2017 ◽  
Author(s):  
Xue Chen ◽  
MingYan Gu ◽  
XianHui He ◽  
Dan Yan ◽  
Jimin Wang ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Coal Particle ◽  
Gas Flow ◽  
Ignition Time ◽  
Particle Diameter ◽  
Combustion Characteristics ◽  
Gas Temperature ◽  
Flow Temperature ◽  
Particle Ignition ◽  
Coal Particles

A 2-D numerical model of flow, heat transfer, and combustion of coal particles in a laminar gas flow at O2/CO2 atmosphere was developed based on the Eulerian-Lagrangian methodology. The gas-phase combustion was modeled using the GRI-Mech 3.0. The motion of coal particles was simulated using a trajectory model. The model was employed to study the coal ignition time, temperature and mass changes. The effects of particle diameter, the flow temperature and oxygen concentration on the ignition time and the combustion characteristics of coal particles were also investigated. The results obtained show that smaller size particle experiences a shorter ignition time with a higher coal temperature. A higher gas temperature leads to a shorter coal particle ignition time; increasing the flow temperature the difference in the ignition time of different sized coal particles decreases. The coal particle ignition time is decreased when the oxygen concentration is increased.

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