Flue Gas Turbine Research Articles

Multiobjective Optimization Study On the Aerodynamic Performance and Anti-Erosion Characteristics of a Single-Stage Dusty Flue Gas Turbine

Abstract Solid particle erosion of dusty energy recovery turbine blades has a great impact on the operating economics and safety of the unit. To mitigate the erosion of blade and improve the aerodynamic performance of the turbine, a multiobjective optimization method for turbine cascade based on the experimental design method, genetic algorithm and CFD multiphase flow simulation was developed. The optimization results show that the number of stator and rotor blades and the trailing edge angle at 50% blade span are the main parameters affecting the efficiency and blade erosion of the dusty turbine. By reducing the number of stator blades and the circumferential bending angle of the stator trailing edge, the impingement velocity and impingement probability of particles impinging on the stator trailing edge decrease by 7.5%~16.8% and 8.9%~46.2%, respectively. Additionally, compared with the original design, the flow separation loss and secondary flow intensity of the rotor cascade are suppressed by adjusting the load distribution and inlet attack angle of the rotor; thus, the turbine efficiency effectively improves by 2.28%. Meanwhile, the optimized blade reduces the particle impingement velocity and probability on the rotor leading edge, and the erosion condition of the rotor leading edge decreases by 70%.

Numerical analysis of catalyst particle deposition characteristics in a flue gas turbine with an improved particle motion and deposition model

To more accurately understand and predict the deposition behavior of catalyst particles in the flue gas turbine cascade, test and numerical combined study is performed in this paper. Based on the systematic analysis of the deposition process and physical mechanism of the catalyst particles, the traditional DRW model, critical velocity particle deposition model and removal model were corrected with the user defined function custom function and validated with the actual deposition morphology. On this basis, the effects of the particle Stokes number and flue gas parameters on the particle deposition characteristics of the flue gas turbine cascade were detailed investigated. The results show that the revised DRW model, critical velocity and removal model can more accurately predict the deposition location and deposition rate of particles in the turbine cascade. With the increase in the Stokes number of particles, the average particle impact rate on the blade surface gradually increased, while the average deposition rate showed a trend of first increasing and then decreasing. The average deposition rate of particles in the rotor blade surface is roughly twice as high as that in the stator surface. With the increase of the flue gas expansion ratio, the deposition rate of particles less than 3 μm gradually increases, while the deposition rate of particles greater than 3 μm tends to decrease. In addition, the change in the flue gas expansion ratio has no obvious effect on the particle deposition distribution in different size ranges.

Numerical study on aerodynamic performance and particle erosion characteristics of flue gas turbine

The 3-D numerical simulation method is coupled with erosion and particle rebound models based on the results of high temperature erosion tests to systematically study the gas-solid two-phase flow characteristics of a flue gas turbine for the first time. The aerodynamic loss characteristics of the flue gas-steam mixtures and particle erosion mechanism in the flue gas turbine cascade under design and non-design conditions are investigated. The results indicate that the mixing loss of cooling steam and gas, secondary flow loss, and separation loss significantly affect the entropy increment of the rotor cascade. The isentropic efficiency of the flue gas turbine under the design condition is 78.74%. The radial inflow of wheel cooling steam from the axial clearance has a radial impact and mixing effect on the mainstream flue gas, enhancing the generation and development of the secondary flow vortex in the rotor cascade. When the dimensionless cooling steam flow rate is reduced from 1 to 0.6, the isentropic efficiency of the flue gas turbine increases by approximately 0.9%. By contrast, when the dimensionless cooling steam flow rate increases from 1 to 2, the isentropic efficiency decreases by 0.42%. The erosion rate of the leading and trailing edges of the rotor is higher than those at other streamwise locations. The erosion of the rotor leading edge and the blade-tip trailing edge is caused by the high speed impact of particles above 10 ?m, while the erosion of the rotor root is caused by the grinding of 1-5 ?m particles carried by the secondary flow.

A novel damage identification method for flue gas turbine blades based on tip timing

Tip timing signal analysis has been applied to the online condition monitoring of high-speed blades. However, traditional tip timing analysis methods are not suitable for low-speed flue gas turbines. Therefore, this paper proposes a novel blade tip timing signal analysis method based on an investigation of the dynamic response characteristics of low-speed blades. First, the finite element modal theory is introduced to analyze the characteristics of blade damage. Second, an equivalent cantilever beam analysis model of flue gas turbine blades is established under complex environment and working conditions. In order to monitor the variation of local stiffness, a damage identification method based on the variation of the free end deflection of the equivalent cantilever beam is proposed. Finally, a rotating blade tip timing monitoring testing rig is established to verify the feasibility of the proposed method. The results show that the cracks originating at about 80% of the blade height have the greatest influence on blade stiffness, followed by blade root. The calculated blade damage parameters are 4.8464 mm and 3.7588 mm, and the crack influencing factors are 4.7476 and 3.6822, respectively, indicating that the change trend is consistent with the blade damage rules.

Research on the influence of honeycomb cell blockage on the seal leakage characteristics

Abstract The accumulation of catalyst dust at the honeycomb seal for a long time will lead to the honeycomb seal cell blockage, weaken the seal effect of the honeycomb seal, and directly affect the safe and stable operation of the flue gas turbine. Therefore, a research on the influence of honeycomb cell blockage on the seal leakage characteristics is carried out. The flow field model of honeycomb seal is established, and the influence of cell blockage on the leakage characteristics of honeycomb seal is analyzed. A seal leakage characteristic experiment bench is built, and the numerical simulation results are verified by the experiment bench. Compared with the honeycomb seal without blockage, the leakage of the honeycomb seal with a blockage rate of 25% increases by about 6.5%, while the leakage of the honeycomb seal with a blockage rate of 25% obtained by the experiment increases by about 6.3%. The numerical simulation results are in good agreement with the experimental results. The results of this research provide theoretical support for revealing the seal leakage characteristics of honeycomb seals under blockage faults.

Analysis and Prevention and Control System of Domino Accident Risk Data in Chemical Parks Based on Topological Neural Network.

A topologically based neural network algorithm is used to conduct an in-depth study and analysis of domino accident risk data in chemical parks, and this is used to construct a prevention and control system applied to the safety prediction of chemical parks. Firstly, the operating model of the flue gas turbine is expanded and analyzed according to the basic theory of topology, and the object element model is constructed to determine the feature vector and potential risk level. Then, the idea of differential evolution is introduced into the topological neural network to solve the problem that the learning rate and weighting coefficients are difficult to determine, and then the complete DE-ENN algorithm is proposed and tested with the UCI standard data set to verify the effectiveness of the algorithm. Finally, the algorithm is applied to the potential risk identification of the smoke machine operation model, and the experimental results show that the method not only has a simple structure, short running time, and high prediction accuracy but also has excellent generalization ability. For the inherent risk and domino effect risk of chemical equipment in chemical fiber enterprises, the accident risk assessment method based on the protection layer analysis method is proposed; combined with the probability of domino accident and personnel vulnerability model based on the comprehensive analysis of the research results of the allowable risk standard, the allowable risk standard applicable to chemical fiber production enterprises in China is proposed. Given the potential accident risk characteristics of chemical fiber production enterprises, the calculation method of firefighting demand and firefighting capacity of firefighting system is given; the index system of firefighting system emergency response capacity assessment is constructed from three aspects of firefighting system integrity, reliability, and effectiveness, and the assessment model and grade classification standard of firefighting emergency response capacity of chemical fiber production enterprises are determined.

Vibration fault signal analysis and diagnosis of flue gas turbine

Flue gas turbine is a kind of typical rotating machinery. It uses the flue gas expansion which contains a lot of heat energy and pressure energy generated in the catalytic cracking process to drive the axial-flow compressor or generator to rotate. Due to the complex structure, bad operating environment, poor stability, and large vibration of the flue gas turbine, its failure rate is high, which causes immeasurable economic losses and safety hazards. Therefore, how to effectively obtain, extract and identify the fault information of flue gas turbine is a difficult problem in the field of fault diagnosis technology. In this paper, aiming at two kinds of faults in the tp9-90 flue gas turbine system, i.e., rotor misalignment and unbalance causing excessive vibration, the corresponding geometric model and mathematical model are established, and the fault mechanism is revealed. Through on-line monitoring of flue gas turbine rotor vibration signal, the running state of flue gas turbine is comprehensively analyzed, and the technological transformation is carried out according to the fault causes, the improved flue gas machine runs smoothly, and the vibration and failure rate are obviously reduced. This study provides an important reference for condition monitoring and fault diagnosis of flue gas turbines.

Simulation Study on the Effect of Flue Gas on Flow Field and Rotor Stress in Gas Turbines

A flue gas turbine is the main energy recovery equipment in a heavy oil catalytic cracking unit. Blade erosion and fracture are the main reasons for gas turbine failure. In this study, the characteristics of the flow field and rotor stress in the gas turbine under different fume volumes are simulated and analyzed by simulation software (ANSYS). The influences of fume volume on the high-temperature fume flow field, temperature, velocity, catalyst particle movement rotor stress in the gas turbine, as well as the influence law of flue gas flow on temperature gradient, pressure gradient, velocity distribution, and the main position of blade erosion were studied. The stress distribution and maximum stress position of the impeller were also determined. It was found that the variation trends of the pressure gradient in the calculation domain of the gas turbine under different fume volumes are similar. The pressure on the working face of the rotor blade decreases gradually along the flow direction of the high-temperature fume. The highest pressure appears near the sharp corner with the large radius of the front edge of the rotor blade. The variation of the fume flow rate has little influence on the temperature field of the entire machine. The erosion wear of the rotor blade mainly occurs in the leading edge and tail. The maximum stress point of the blade is located at the large fillet of the first pair of tenon teeth. The maximum stress point of the disc is located at the large fillet of the third pair of tenon teeth. It is believed that these research results have reference help for analyzing the typical failure causes of flue gas turbine, optimizing the actual operating conditions and the reconstruction design of flue gas turbine.

Modeling and numerical analysis of the effect of blade roughness on particle deposition in a flue gas turbine

ABSTRACT Particle deposition is very common in flue gas turbines. To calculate particle deposition, considering the effects of blade roughness on gas flow and particles, a modeling and computational study on particle deposition is presented. The numerical results are in good agreement with the experimental results. The effect of roughness on deposition in the flue gas turbine was investigated numerically. The results show that most of the deposited particles are 300 μm, the effect of blade roughness on particle deposition is not obvious. The effect of blade surface roughness on particle deposition is also verified through experimentation. Even when the gas temperature was varied from 300 to 700 °C and the particle concentration varied from 100 to 400 g/m3, all the experimental results show that the reduction in surface roughness is an effective method to reduce particle deposition in a flue gas turbine.

Numerical study of inlet Reynolds number in fine particles deposition processes in a flue gas turbine

In this study, the effect of Reynolds number on deposition in a flue gas turbine is numerically investigated by conducting a study on flow channels between stator blades and rotating blades. The turbulence flow is modeled by the Renormalization-group (RNG) k-ε model, and particle motions are simulated by the discrete particle model (DPM) with User Defined Function (UDF). Numerical investigation is conducted for particles in the size of dp < 10.78 μm. These results show that inlet Reynolds number helps deposition develop except the pressure side of the stator blade. The pressure drop Δp, temperature drop ΔT and velocity improvement Δv increase with the increase of Re. Deposition morphologies on the blades are notably different depending on particle size. Smaller particles of dp < 3 μm settle down on the blades at a 10 or even 109 times rate of larger particles. The main areas of deposition include the suction surface of stator blades, the pressure surface of rotating blades and the zone near the hub and casing on the suction surface of rotating blades.

Model of Particle Deposition and Adhesion on Blade Surface of Flue Gas Turbine

Model of Particle Deposition and Adhesion on Blade Surface of Flue Gas Turbine

Solid particle erosion-wear behaviour of Cr3C2–NiCr coating on Ni-based superalloy

There are very few attempts to explore the erosion-wear behaviour of the Cr3C2–NiCr coating deposited on the nickel-based superalloy employed to resist the solid particle erosion damages for flue gas turbine blade. This work focuses on the erosion mechanism of Cr3C2–NiCr coating under service conditions. A 75 wt% Cr3C2–25 wt% NiCr composite coating was prepared on Ni-based superalloy substrate material using high-velocity oxygen-fuel spraying technique. The coating surface has been characterized. The erosion behaviour and the effects of air pressure, impingement angle, erosion temperature and particle size on the erosion resistance of coating were studied. The results indicate that the volume erosion rate of the specimen increases gradually with the increase in air pressure. The volume wear rates of coating material increase with the decrease in coating thickness. Coating shows better erosion resistance at 90° impact angle as compared to 30° impact angle. The maximum volume erosion rate occurs at impact angle of 60°. So, the combined mode of erosion mechanism (i.e. ductile and brittle) is observed in the Cr3C2–NiCr coating on nickel-based superalloy. The erosion-wear resistance of the materials can be improved at high temperatures. With the increase in the particle size, the volume erosion rates of the coating material increase. Erosion particle size and shape are the key factors that influence the erosion-wear behaviour.

Promising Direction of Perfection of the Utilization Combine Cycle Gas Turbine Units

Issues of improving the efficiency of combined cycle gas turbines (CCGT) recovery type have been presented. Efficiency gas turbine plant reaches values of 45 % due to rise in temperature to a gas turbine to 1700 °C. Modern technologies for improving the cooling gas turbine components and reducing the excess air ratio leads to a further increase of the efficiency by 1-2 %. Based on research conducted at the Tomsk Polytechnic University, it shows that the CCGT efficiency can be increased by 2-3 % in the winter time due to the use of organic Rankine cycle, low-boiling substances, and air-cooled condensers (ACC). It is necessary to apply the waste heat recovery with condensation of water vapor from the flue gas, it will enhance the efficiency of the CCGT by 2-3 % to increase the efficiency of the heat recovery steam boiler (HRSB) to 10-12 %. Replacing electric pumps gas turbine engine (GTE) helps to reduce electricity consumption for auxiliary needs CCGT by 0.5-1.5 %. At the same time the heat of flue gas turbine engine may be useful used in HRSB, thus will increase the capacity and efficiency of the steam turbine.

Numerical study of particle deposition and scaling in dust exhaust of cyclone separator

The solid particles accumulation in the dust exhaust cone area of the cyclone separator can cause the wall wear. This undoubtedly prevents the flue gas turbine from long period and safe operation. So it is important to study the mechanism how the particles deposited and scale on dust exhaust cone area of the cyclone separator. Numerical simulations of gas-solid flow field have been carried out in a single tube in the third cyclone separator. The three-dimensionally coupled computational fluid dynamic (CFD) technology and the modified Discrete Phase Model (DPM) are adopted to model the gas-solid two-phase flow. The results show that with the increase of the operating temperature and processing capacity, the particle sticking possibility near the cone area will rise. The sticking rates will decrease when the particle diameter becomes bigger.

Vibration Sensor Based Intelligent Fault Diagnosis System for Large Machine Unit in Petrochemical Industries

Fault diagnosis is an area which is gaining increasing importance in rotating machinery. Along with the continuous advance of science and technology, the structures of rotating machinery become increasingly of larger scale and higher speed and more complicated, which result in higher probability of various failure in practice. In case one of the most critical components of machinery or equipment breaks down, it cannot only cause enormous economic loss, but also easily cause the loss of many people's lives. It is important to enable reliable, safe, and efficient operation of large-scale and critical rotating machinery, which requires us to achieve accurate and fast diagnosis of fault which has occurred. Aiming at dynamic real-time vibration monitoring and vibration signal analysis for large machine unit in petrochemical industry, which cannot realize real-time, online, and fast fault diagnosis, an intelligent fault diagnosis system using artificial immune algorithm and dimensionless parameters is developed in this paper, innovated with a focus on reliability, remote monitoring, and practicality and applied to the third catalytic flue gas turbine in a petrochemical enterprise, with good effects.

Weak fault signature extraction of rotating machinery using flexible analytic wavelet transform

Extracting and revealing the weak periodic fault vibration impulses is reasonable for damage detection of rotating machinery. However, the widely used dyadic WT suffers fixed frequency partition manner and low oscillating bases which would weaken its performance in weak fault detection. A new method based on flexible analytic wavelet transform (FAWT) is proposed in this article. Employing fractional and arbitrary scaling and translation factors, FAWT possesses attractive properties such as flexible time–frequency (TF) covering manner, better shift-invariance and tunable oscillatory nature of the bases, offering proper wavelet frame and bases shape to match the weak fault components. Moreover, FAWT is effective in revealing the amplitude modulation feature of the periodic fault impulses that occur in some damaged rotating components. The applications to a rolling bearing, a planetary gearbox of, and a flue gas turbine unit show that the proposed method is effective in extracting weak impulsive fault signature.

The Failure Cause and Fault Tree Analysis to the Blade of Flue Gas Turbine

Flue gas turbine is one of the highest failure rate of the power equipment in oil refinery now.It is a key role to achieve saving energy and reducing consumption, the goal ofpollution reduction and the safe, reliable and efficient operation of the flue turbine in refinery. Therefore, it is of great significance to the fault diagnosis of the blade by summarizing the fault reason of the flue gas turbine and using fault tree analysis.

Reconstruction‐based fault prognosis for flue gas turbines with independent component analysis

ABSTRACTOnline detection and prognosis are very important for the safe operation of flue gas turbines. Compared with univariate monitoring of the process, multivariate process monitoring is more effective and can capture abnormal situation in the early stage. This paper proposes a new multivariate fault prognosis framework for the flue gas turbine with a hidden fault process based on independent component analysis (ICA). ICA is a statistical method for identifying underlying independent factors or components in multivariate data. First of all, the non‐Gaussian measurements are modeled by the ICA model, and three indices are used for fault detection. Once several faulty samples are collected, fault directions can be extracted for the reconstruction. Then, a reconstruction‐based method is proposed to estimate the fault magnitude with the most sensitive index. At last, the fault magnitude is predicted by the support vector machine model. Test results for K‐103 catalytic flue gas turbine clearly showed that the proposed fault prognosis method is more efficient than traditional methods. The results also demonstrate support vector machine method has advantages over auto regression approach. © 2013 Curtin University of Technology and John Wiley &amp; Sons, Ltd.

Flue Gas Turbine Fault Analysis and Improvement Measures

The flue gas turbine discussed in this article have relatively backward pneumatic design, low operating efficiency, as well as problems of vibration, catalyst accumulation and fouling etc. It cannot realize better generating power effect because of short running cycle, high failure rate, and low recovery of heat and pressure energy generated of high temperature flue gas. To solve the above problems, this article proposes failure analysis. Flue gas turbine problems appear for the main reasons: the steam of the regeneration standpipe reach the regenerator, lead to catalyst breaking and give rise to a large number of catalyst fines, which causes the third cyclone separator blocked and the flue gas turbine fouled. Then, repair the leakage point of regeneration standpipe, maintain smooth operation,and transform leaf type of flue gas turbine. The flue gas turbine restored power generation status after overhaul. achieve the purpose of high efficiency and long-term stable operation.

Stress and Strain Analysis of First Stage Rotating Blades of Flue Gas Turbine Blades

Flue gas turbine is the key equipment of the refinery catalytic cracking unit and blades are important component parts. However, blades faults are accounted for a large proportion of various failures in the flue gas turbine. According to it, ANSYS finite element software is applied to analysis Level 1 dynamic blade stress and strain and obtained the stress and strain distribution of the gas turbine, the greatest stress is at the root of the blade suction side and pressure on both sides of the Ministry basin, the maximum stress intensity value is 169.698MPa and the maximum equivalent elastic strain is 0.194×10-3.Then at the basic of the stress analysis to strength check of blade’s body and at last proved that it meet the design stress intensity. Through theoretic analysis and the result of stress and strain analysis is proved that ANSYS software is acceptable and efficient. At the same time it provides a theoretical basis for engineering.