Real Boiler Research Articles

Crown ether functionalized silver nanoparticles for colorimetric detection of alkali earth metals in real boiler feed water samples

Crown ether functionalized silver nanoparticles for colorimetric detection of alkali earth metals in real boiler feed water samples

Penetration of a Pulsed Gas Jet through a Package of Heat Exchange Tubes

The slagging of heating surfaces by fly ash significantly complicates the long term operation of solid-fuel boilers. Gas pulse technologies offer a potentially convenient, inexpensive, yet efficient way for online slag deposits removal. The creation and application of real boiler cleaning systems using gas pulse technologies is a relatively new direction in the energy sector and requires scientific research on various aspects. In this work, the numerical investigation of the gas-dynamic flow arising when the package of heat-exchange tubes is blown with single air jet created by a pneumopulse cleaning system has been carried out. The forces acting on the heat-exchange tubes located at distances 1.0 m and 2.0 m from the exhaust nozzle with various configurations of tubes in the package have been determined. It is shown that an increase in the pressure of the generated air jet makes it possible to significantly increase the acting forces at large distances from the exhaust nozzle. The results of this study and similar calculations for real geometry will increase the validity of engineering solutions used in the development of pneumopulse cleaning systems for large power boilers.

3D Visualization of the Results of Using Modern Ofa Technology on the Example of Real Boiler

The leading place in the world for environmental protection is currently occupied by the protection of the air basin. And the main sources of atmospheric pollution are industrial enterprises, motor transport and thermal power plants. Thus, there is an obvious need to increase attention to the problems of the innovation sector, mainly in the areas of technical improvement of heat and power industry enterprises. Therefore, the study of the problems of reducing the amount of harmful emissions into the atmosphere, control and regulation of its quality, as well as the study of new various methods of innovative development of thermal power is an urgent task at present, requiring a serious scientific approach. In the proposed work, computer experiments were carried out in the field of innovative energy production technologies (the use of modern "sharp blast" OFA technology) at a specific thermal power facility of the enterprise of the Republic of Kazakhstan. During the experiment, various ways of supplying additional air through OFA nozzles were investigated: OFA=0% (basic version without additional air supply), OFA=10% and OFA=18%. For these three modes, a comparative analysis of the aerodynamics of the furnace part of the boiler was performed according to the obtained distributions of the temperature and concentration fields of nitrogen oxide NO over the entire volume of the combustion chamber. The results obtained were compared with experimental data obtained during experiments conducted directly at the CHP.

A New Recurrent Radial Basis Function Network-based Model Predictive Control for a Power Plant Boiler Temperature Control

In this paper, a new radial basis function network-based model predictive control (RBFN-MPC) is presented to control the steam temperature of a power plant boiler. For the first time in this paper the Laguerre polynomials are used to obtain local boiler models based on different load modes. Recursive least square (RLS) method is used as observer of the Laguerre polynomials coefficient. Then a new locally recurrent radial basis function neural network with self-organizing mechanism is used to model these local transfer function and it used to estimate the boiler future behavior. The recurrent RBFN tracks system is dynamic online and updates the model. In this recurrent RBFN, the output of hidden layer nodes at the past moment is used in modelling, So the boiler model behaves exactly like a real boiler. Various uncertainties have been added to the boiler and these uncertainties are immediately recognized by the recurrent RBFN. In the simulation, the proposed method has been compared with traditional MPC (based on boiler mathematical model). Simulation results showed that the recurrent RBFN-based MPC perform better than mathematical model-based MPC. This is due to the neural network's online tracking of boiler dynamics, while in the traditional way the model is always constant. As the amount of uncertainty increases, the difference between our proposed method and existing methods can clearly be observed.

Carbide-laden coatings deposited using a hand-held high-velocity air-fuel (HVAF) spray gun

Driven by sustainability and cost considerations, there is growing interest in power generation utilizing renewable sources, especially biomass and waste. While premature degradation of power plant components due to corrosion is well-known, erosion can be a dominant damage mechanism in plants that use “pure” biomass with less corrosive elements like Cl, K, etc. Circulating fluidized bed (CFB) parts are prone to erosion-driven damage and demand periodic re-protection or replacement. In response to the above, this preliminary study evaluates a selection of complex carbide-based coatings to enhance protection against erosion to prolong service life of boiler components. Recognizing on-site coating requirements of real boiler applications, a specific focus is on evaluating performance of a hand-held high-velocity air-fuel (HVAF) spray gun and compare it with the current state-of-the-art high-velocity oxy-fuel (HVOF) deposition. Coatings developed by the above routes have been characterized with microstructural analyses, and their performance evaluated and ranked in an air-jet erosion rig at various impact angles.

A LoRaWAN Carbon Monoxide Measurement System With Low-Power Sensor Triggering for the Monitoring of Domestic and Industrial Boilers

Gases emitted by domestic and industrial boilers significantly contribute to the overall pollution levels of urban environments. Among these gases, carbon monoxide (CO) represents a marker of the efficiency of the combustion processes, and the monitoring of its emissions, even if often neglected, is crucial to improve energy efficiency and environmental safety within a smart city context. This article aims at describing a real-time, remote system for the monitoring of CO emissions of domestic and industrial boilers based on the use of a low-power long-range wide-area network (LoRaWAN) sensor node. In particular, the proposed solution is based on an ad hoc front-end circuit acting as a power-gating system for the rest of the sensor node, exploiting the output of the CO sensor as a trigger to activate the data acquisition and transmission module. Such a solution allows to notably increase the lifetime of the node, allowing its powering using rechargeable Li-ion batteries. Tests were performed on a real boiler in order to demonstrate the validity of the proposed solution. Power consumption of the sensor node was experimentally measured: theoretical analysis demonstrated an ideal lifetime for the sensor node up to two and half years.

Erosion corrosion behaviour and mechanical properties of wire arc sprayed Ni-Cr and Ni-Al coating on boiler steels in a real boiler environment

ABSTRACT The aim of the current investigation is to evaluate the erosion-corrosion (E-C) performance of wire arc sprayed Ni-20Cr and Ni-5Al coatings on T22 and SA516 boiler steels in a real boiler environment. The microstructure, mechanical properties and high temperature E-C performance of the deposited coatings were investigated. The E-C behaviour of the test samples was determined in the superheater zone of the coal fired boiler at 750°C for fifteen cycles, where each cycle involved 100 hours of heating followed by 1hour of cooling. Thickness loss data was used to determine the E-C behaviour of the coating. XRD, SEM/EDS were used to analyse the test samples. Ni-20Cr coated SA516 steel decreased maximum E-C rates by 98.05%, while Ni-5Al coated T22 steel reduced E-C by 68.63% than the base steel. This higher E-C resistance is due to the formation of protective phases (Cr2O3, NiO and Al2O3) and better mechanical properties of the coatings.

Treatment of the real boiler cleaning wastewater in an anaerobic fluidized bed microbial fuel cell: Organic matter degradation, bioelectrochemistry, and kinetics

A single chambered air cathode anaerobic fluidized bed microbial fuel cell (AFB‐MFC) was simultaneously used to dispose of the real boiler cleaning wastewater (BCW) containing a high concentration of citric acid and to generate renewable energy. At the temperature of 40 °C and flow rate of 5.22 mL/s, the removal efficiency and power density were improved in AFB‐MFC with the abiotic cathode of the Pt/C modified carbon cloth. With the real boiler cleaning wastewater fed as substrate, the maximal removal efficiency of chemical oxygen demand (COD) in AFB‐MFC was up to 90 %, which was higher than the corresponding value of 84 % obtained in the anaerobic biological fluidized bed reactor (ABFBR). The maximum voltage and the maximum power density were 424.6 mV and 18.68 mW/m2, respectively, when the external resistance was 5000 Ω. Furthermore, the Haldane inhibition model was well fitted with experiment data (R2 = 0.97–0.98) in AFB‐MFC/ABFBR. The inhibition of citric acid degradation in ABFBR was stronger than that of AFB‐MFC. The bioelectrochemical system of AFB‐MFC not only improved the charge transfer and but also accelerated the reaction rate of citric acid. The reduction of the ferric ion and oxidation of ferrous ion in AFB‐MFC played important roles in the degradation reaction of critic acid.

The influence of potassium-rich biomass ashes on steel corrosion above 550 °C

The slagging, fouling and high temperature corrosion are major problems in biomass-firing units and lead to heat transfer limitation, bed agglomeration and metal surface degradation. This paper reports the results of the laboratory-scale corrosion studies of selected steel grades (16Mo3, 10CrMo9–10, X10CrMoVNb9–1, X7CrNiNb18–10) under biomass ash deposits. Five biomass ashes (3 agricultural biomass and 2 energy crops) were used for corrosion tests. Selected samples were doped with 0.1 and 0.5% wt. of KCl to simulate salt condensation process occurring in a real boiler. The corrosion experiments were carried out under oxidizing conditions, at 560 °C and 610 °C for 168 h. To determine the corrosion rate the mass of steel samples were measured after 24, 72 and 168 h. The corrosion products were analysed using SEM-EDS technique. The results showed that oxide scale formation rate determines the overall corrosion mechanism and the influence of ash deposits on steel. For low-chromium steels the oxidation rate is significant and a scale is a protective barrier between the deposit and metal surface limiting further oxidation process. The highest influence of ash on corrosion process was observed for high-chromium steels. However, high-chromium steels show the highest corrosion resistance.

Droplet combustion and sooting characteristics of UCO biodiesel, heating oil and their mixtures under realistic conditions

The droplet combustion characteristics of conventional heating oil, UCO biodiesel and their mixtures (10 and 20% biodiesel by volume) were examined in a free-falling droplet combustion facility designed to approach the typical temperature and oxygen conditions around individual droplets in real boiler flames. Moreover, and given the importance of avoiding effects due to gravity or convection in this type of experiments, the quite spherical soot shells recorded (infrequent event in free-falling droplet combustion studies) reveal a configuration close to 1-D, even though tests were performed at normal gravity. The droplet combustion characteristics were evaluated at four different oxygen levels (0,3,5 and 10% O2), and comprise droplet size evolution, burning rates and sizing of the occurring soot shells and envelope flames. Results show indistinguishable behaviors between heating oil and their mixtures, whereas biodiesel displays longer initial heating transients and higher quasi-steady burning rates. Even though the UCO biodiesel studied is highly unsaturated, no signs of polymerization were observed for any of the tests. In addition to these combustion characteristics, an aspirating soot probe was used to quantitatively evaluate the propensity to soot of each fuel at different oxygen levels. The amount of collected soot was found to significantly decrease with biodiesel addition, even though similar results were obtained for both mixtures. The practically identical droplet combustion characteristics between heating oil and its mixtures with biodiesel, in addition to the lower propensity to soot of the latter, support the feasibility of using such blends as drop-in replacement for conventional heating oil. The experimental results obtained are thought to constitute a valuable database for the development and validation of modeling tools for the prediction of droplet evaporation and combustion of practical fuels in realistic conditions.

Numerical simulation research on the unique thermal deviation in a 1000 MW tower type boiler

In this paper, a comprehensive numerical simulation, which was verified by measurement and design data, was conducted to investigate the issues of thermal deviation in a 1000 MW tower type boiler. Based on this, the cause of thermal deviation was found: a large swirling momentum intensity in the furnace leads to a great deflection of SOFA and then unburned carbon in fly ash gathering in the furnace center is extremely hard to be burn out. At last, a high temperature flame ring occurs at the gas entrance of platen heater zone, resulting in the thermal load deviation of platen heaters. The influences of deflection angle of SOFA nozzles and the main burners in the primary combustion zone were also investigated. The results show that an optimal deflection angle of SOFA nozzles and the main burners in the primary combustion zone can reduce the thermal deviation by decreasing the swirling momentum intensity in the whole area of full furnace. It suggests that modifying the deflection angle of SOFA nozzles to −18° is the best strategy for realizing a minimum thermal deviation case. The results of test on a real boiler adopting this best strategy show that it is effective to reduce thermal deviation.

Ammonia desorption from fly ash

The main source of ammonia in ash are residues from an unreacted NH3 from the denitrification process, either from SCR or SNCR systems. The paper discusses the standards of NH3 content in fly ash and presents the most commonly used methods of removing excess ammonia from fly ash. In the next part of the work the results of laboratory tests on NH3 desorption are presented. Desorption was performed on samples of fly ash taken from the electrostatic precipitator of real PC boiler. Removal of NH3 from the ash was carried out in a heating chamber at 130°C and 150°C and detected by an analyser equipped with a NDIR sensor. Additionally, at the temperature of 130°C, the NDIR and analytical methods were compared (in accordance with the BN-750541-05 procedure) and the measurement uncertainty of both methods was estimated.

Promotion of Anthracite Burnout for a 300 MWe Down-Fired Boiler with a Novel Combustion Technology

Eccentric-swirl-secondary-air combustion technology (ESSACT) has been applied to a 300 MWe anthracite- and down-fired boiler with swirl burners. To improve burnout performance of the retrofitted boiler, the effects of primary air ratios on flow and combustion characteristics are investigated via cold-model aerodynamic experiments and industrial experiments. When primary air ratios are 17.09 and 19.08%, a deflective flow field occurs, and with increasing the primary air ratio from 21.11 to 24.75%, a symmetrical “W” flow field is formed. With increasing the primary air ratio from 17.09 to 24.75%, the maximum dimensionless vertical velocity of air flow near the front wall increases linearly from 0.364 to 0.521. Accordingly, the penetration depth in the real boiler increases by approximately 2.88 m. For a primary air ratio of 18.47%, the temperatures at the burner exit and in the furnace hopper near the front and rear walls are both seriously asymmetrical and the combustion path of pulverized coal particles b...

KAJIAN SUMBER ENERGI PADA PENGOLAHAN KELAPA SAWIT MENJADI CRUDE PALM OIL (CPO) DI PT. ALNO AGRO UTAMA SUMINDO OIL MILL, BENGKULU UTARA

Increasing demand for Crude Palm Oil (CPO) as the vegetable oil was causing the industry to cultivate palm oil increased, so that the energy required to produce CPO also increased. The purpose of this study is to identify the type, source and calculate the amount of energy needs, calculate the level of efficiency and energy savings opportunities. Stages of the research are initial energy analysis, a detailed energy, and energy analysis in processing systems. Based on the research results, to produce each kg of CPO processing capacity of 60 ton TBS / hour with a recovery rate of 20.59% of primary energy needs of 16.200679 MJ / kg. Real boiler efficiency of 45.69%, the real efficiency of the turbine was 94, 86%. Turbine efficiency to generate electrical energy by 1.09%, the technical efficiency of 66.80% turbines, diesel generators technical efficiency of 47.25%, the technical efficiency of electric motors by 59.37%. The total efficiency of electricity use by 4,75%, the efficiency of diesel estate of 1.379% and the efficiency of the use of steam at 93.77%. Energy can be saved by 0.0442 MJ / kg with a description of human powered energy of 0.0004316 MJ / kg, energy electrical energy by .04372 MJ / kg. While energy can be stored on the excess energy to fuel biomass boiler was 1.45 MJ / kg

Artificial neural networks application for solid fuel slagging intensity predictions

Slagging issues present in pulverized steam boilers very often lead to heat transfer problems, corrosion and not planned outages of boilers which increase the cost of energy production and decrease the efficiency of energy production. Slagging especially occurs in regions with reductive atmospheres which nowadays are very common due to very strict limitations in NOx emissions. Moreover alternative fuels like biomass which are also used in combustion systems from two decades in order to decrease CO2 emissions also usually increase the risk of slagging. Thus the prediction of slagging properties of fuels is not the minor issue which can be neglected before purchasing or mixing of fuels. This however is rather difficult to estimate and even commonly known standard laboratory methods like fusion temperature determination or special indexers calculated on the basis of proximate and ultimate analyses, very often have no reasonable correlation to real boiler fuel behaviour. In this paper the method of determination of slagging properties of solid fuels based on laboratory investigation and artificial neural networks were presented. A fuel data base with over 40 fuels was created. Neural networks simulations were carried out in order to predict the beginning temperature and intensity of slagging. Reasonable results were obtained for some of tested neural networks, especially for hybrid feedforward networks with PCA technique. Consequently neural network model will be used in Common Intelligent Boiler Operation Platform (CIBOP) being elaborated within CERUBIS research project for two BP-1150 and BB-1150 steam boilers. The model among others enables proper fuel selection in order to minimize slagging risk.

Thermodynamic Equilibrium Model Applied To Predict the Fouling Tendency in a Commercial Fluidized-Bed Boiler, Combusting Solid Waste

A thermodynamic equilibrium model, combined with an advanced fuel analysis, was applied to predict the fouling tendency in a commercial bubbling fluidized-bed (BFB) boiler, combusting a mixture of solid waste. In order to enhance the performance of the model, further modifications were made, considering the combustion pattern in the fluidized-bed system and also the temperature profile in the combustion zone. The modeling was performed using Factsage, and experimental data obtained during the full-scale measurements were used as input for the model, simulating the deposit formation in the real boiler. The simulation results were then compared with the results obtained during the full-scale combustion tests to estimate the accuracy and validity of the applied model. The thermodynamic equilibrium modeling proved to be a reliable tool for predicting the fouling in the BFB boiler, thus determining the fraction of the melt in the deposited salts formed on the heat transfer surfaces during the flue gas condensation. The calculations showed that the ratio of the SO2 to alkali chloride concentration in the flue gas was the decisive factor that affected the rate of the deposit formation in the boiler. Both the simulation and the experimental results indicated that lower bed temperatures and cocombustion of P-rich fuels decrease the deposition buildup in the boiler.

Research on Marine Fuel Boiler Drum Water Level Model and Dynamic Analysis

This article first mathematical model of boiler water level, and then in MATLAB/ SIMULINK environment, the model simulation, and thus the dynamic characteristics of the model for analysis. Many real boiler parameters and variables, complex, by simplifying the modeling process, ignores some factors and variables, a simple model can be obtained results almost true fit. Boiler water level of the model established in considering the effect of steam flow and water flow of two factors.

Boiler model and simulation for control design and validation

Abstract A plant validated boiler simulator is a very useful tool for controls design, analysis and performing experiments because of the cost involved in doing experiments on a real boiler or even lab-boiler. This paper presents the dynamic model simulator of a typical power-plant boiler derived based on the first principles and a hybrid approach of suitably combining lumped and distributed modeling approach for the relevant subsystems. The developed model simulator is validated using an actual plant-data covering the dynamic plant startup scenario. The plant-data of steam flow-rate, feed-water flow-rate, feed water temperature, and heat input defines the boundary condition of the plant startup, and the model-simulated response of the drum-level and pressure are compared with the actual plant-data of boiler drum-level and pressure. The validation results are very encouraging considering the challenges posed by complex behavior and uncertainties in the actual power-plant boiler-drum, and the measurement inaccuracies in the industrial plant conditions.

Sensor fault estimation in the framework of model predictive control. Boiler case study

This paper deals with a nonlinear model predictive control designed for a boiler unit. The predictive controller is realized by means of a recurrent neural network which acts as a one-step ahead predictor. As the automatic control system can hide faults from being observed, the control system is equipped with a fault diagnosis block. It is realized by means of the binary diagnostic matrix, which is determined on the ground of residuals calculated using a set of partial models. Each partial model was designed in the form of the recurrent neural network. The paper proposes also a methodology of compensating sensor faults. When a sensor fault is isolated, the system estimates its size and based on this information the controller is fed with an estimated, close to real boiler level value. The proposed methodology is tested on the example of the boiler unit simulator. Copyright © 2012 IFAC

Robot for Boiler Header Inspection “LS-01”

Inspection of boiler headers is routinely being performed in Tenaga Nasional Berhad (TNB) thermal power plants. It is very important to inspect boiler header from time to time to check for signs of possible failures because they are thick walled and exposed to various operating conditions. The currently used method is to insert a fiber optic camera probe into the boiler header entry manually by human. This work is very tedious and the inspector often has difficulties to acquire full coverage of the inner wall images. Therefore, it is proposed that a robotic system is developed to carry the fibre optic probe into the boiler headers and assist in a more efficient and reliable boiler header inspection. The developed robot prototype must be small enough to enter the header and must also have the capability to traverse the whole length of boiler header while carrying the existing fibre optic probe as well as cater for boiler header with different diameters. LS-01, presented in this paper, is the first boiler header inspection robot prototype developed, equipped with semi-intelligent system and adjustable entry platform, and is capable of traversing inside boiler headers with various tube configurations. It has been tested in accordance with the engineering requirements set by TNB. Testing has shown the potential of the robot to be applied in a real boiler header inspection processes.