Water Tube Boiler Research Articles

Designing and Evaluation of Bagasse Powered Preheating Device for Seed Cane Hot-water Treatment Plant

As a solution for the energy crisis facing today, the biomass from the sugarcane industry plays major role as an energy source in developing countries. Sugarcane (Saccarhum officinarum) is a globally important source of commercial sugar, which accounts for over 75 percent of the world sugar production. It is estimated that, 30 percent of wet bagasse is produced in a normal sugar mill. Sugarcane bagasse has a heating value of 16792.44 kJ/kg. There is a high potential for using bagasse as a biomass energy source of agricultural sector when considering its thermal properties and the availability. Due to non-availability of disease-free healthy planting materials, sugarcane productivity in Sri Lanka has decreased. Hot water treatment of sugarcane planting material is practiced to control systemic diseases of sugarcane such as ratoon stunting disease and smut. Operating of the existing hot water treatment plants require high electricity for the initial heating process which is very costly and time consuming. This research is focused on designing and evaluating of a bagasse powered pre-heating device for seed cane hot water treatment plant for saving energy and time. The flue gas generated by burning of bagasse was used as the energy source for steam generation inside the pre-heating device. The pre-heating device was designed by combining the concepts of water tube boiler and shell boiler so that the device is named as the combined steam generator. Specifications of the preheating device were calculated according to the heat energy requirement of feed water, steam and fuel energy. Conceptual design for the new pre-heating device was developed considering the system requirements. Based on the concept, a detail design of each part of the device was developed with properly defined dimensions, using a parametric 3D modeling software and simulation process carried out using finite element analysis (FEA). Then the preheating device was completely assembled with fabricated parts. According to the evaluation results, efficiency of the combined steam generator was 80.14%. So the time and the electric energy consumption are reduced by 37% and 99.17% respectively. Keywords: Seed cane, Bagasse, Hot water treatment, Biomass energy, Steam

Review Paper on Different Losses and Efficiency for Combined Type Water Tube and Fire Tube Industrial Boilers

Review Paper on Different Losses and Efficiency for Combined Type Water Tube and Fire Tube Industrial Boilers

Use of Low-quality Biogenic Fuels in a Decentralized Biomass Boiler for Thermal Energy Generation

The KIT generate heat with three hot water tube boilers and a combined heat and power unit. Their operation is based on natural gas. Alternatively, light fuel oil can be used in the hot water tube boilers. For the future the KIT has to achieve climate protection goals and for that to consider about alternative heat generation. This could be the operation of a biomass boiler, which is operated with wood chips or wood pellets. The Institute of Technical Chemistry (ITC) and Facility Management (FM) of KIT in cooperation with medium-sized enterprises now plans to integrate a decentralized biomass boiler into the existing heat supply network of KIT Campus North. The goal for the decentralized biomass boiler is to operate with low-quality biogenic fuel. Within the framework of preliminary studies, the biogenic fuels shall be characterized according to their combustion properties. To enhance sustainability, reduce the consumption of resources and increase economic efficiency, the studies are to focus on the use of waste materials. In addition, the waste flows at KIT and the suited waste shall be identified. The considered materials are lop, sieve residues or other previous identified waste.When planning such a project, legal and licensing-relevant aspects and their consequenses have to be considered. Then, the requirements to be met by the selected fuels will be listed and experimental tests at the “KLEAA” test facility of ITC will be reported. This test facility is a fixed bed reactor used for the characterization of burnout of solid fuels. Studies are aimed at identifying and assessing alternative fuels for future use in biomass boilers. Furthermore side effects such as corrosion, slagging, and emissions shall be taken into account. Depending on the achieved intermediate data the insert of additives to reduce the side effects will be tested. The project findings will be verified in an experimental facility later on.In the proposed paper first results of the preliminary investigations shall be presented.

Development of combined low-emissions burner devices for low-power boilers

Low-power water boilers are widely used for autonomous heat supply in various industries. Firetube and water-tube boilers of domestic and foreign manufacturers are widely represented on the Russian market. However, even Russian boilers are supplied with licensed foreign burner devices, which reduce their competitiveness and complicate operating conditions. A task of developing efficient domestic low-emissions burner devices for low-power boilers is quite acute. A characteristic property of ignition and fuel combustion in such boilers is their flowing in constrained conditions due to small dimensions of combustion chambers and flame tubes. These processes differ significantly from those in open combustion chambers of high-duty power boilers, and they have not been sufficiently studied yet. The goals of this paper are studying the processes of ignition and combustion of gaseous and liquid fuels, heat and mass transfer and NO x emissions in constrained conditions, and the development of a modern combined low-emissions 2.2 MW burner device that provides efficient fuel combustion. A burner device computer model is developed and numerical studies of its operation on different types of fuel in a working load range from 40 to 100% of the nominal are carried out. The main features of ignition and combustion of gaseous and liquid fuels in constrained conditions of the flame tube at nominal and decreased loads are determined, which differ fundamentally from the similar processes in steam boiler furnaces. The influence of the burner devices design and operating conditions on the fuel underburning and NO x formation is determined. Based on the results of the design studies, a design of the new combined low-emissions burner device is proposed, which has several advantages over the prototype.

Calculation of low-cycle fatigue in accordance with the national standard and strength codes

Over the most recent 15 years, the Russian power industry has largely relied on imported equipment manufactured in compliance with foreign standards and procedures. This inevitably necessitates their harmonization with the regulatory documents of the Russian Federation, which include calculations of strength, low cycle fatigue, and assessment of the equipment service life. An important regulatory document providing the engineering foundation for cyclic strength and life assessment for high-load components of the boiler and steamline of a water/steam circuit is RD 10-249-98:2000: Standard Method of Strength Estimation in Stationary Boilers and Steam and Water Piping. In January 2015, the National Standard of the Russian Federation 12952-3:2001 was introduced regulating the issues of design and calculation of the pressure parts of water-tube boilers and auxiliary installations. Thus, there appeared to be two documents simultaneously valid in the same energy field and using different methods for calculating the low-cycle fatigue strength, which leads to different results. In this connection, the current situation can lead to incorrect ideas about the cyclic strength and the service life of high-temperature boiler parts. The article shows that the results of calculations performed in accordance with GOST R 55682.3-2013/EN 12952-3: 2001 are less conservative than the results of the standard RD 10-249-98. Since the calculation of the expected service life of boiler parts should use GOST R 55682.3-2013/EN 12952-3: 2001, it becomes necessary to establish the applicability scope of each of the above documents.

The Characteristics of Oxycombustion of Liquid Fuel in a Typical Water-Tube Boiler

Among the various carbon capture technologies, oxyfuel combustion provides an effective way to reduce CO2 emissions, because of similar flame characteristics, relative to those of air combustion, and its ability to be retrofitted in the existing plants. In this work, combustion of liquid fuel in O2/CO2 environment inside a water-tube boiler has been modeled numerically, and the results were compared with that of the air combustion case. Two cases of oxycombustion were studied: (i) OF21 (21% oxygen (by volume) and 79% CO2 (by volume)) and (ii) OF29 (29% oxygen (by volume) and 71% CO2 (by volume)). The model was extended to study the effects of droplet size and swirl number on the combustion characteristics of the liquid fuel. Probability density function (PDF) was applied to solve the turbulence–chemistry interaction. It was found that the replacement of N2 from air with carbon dioxide significantly reduces the temperature level. It was also found that reducing the CO2 concentration results in an increase ...

Failure analysis of the wall tubes of a water-tube boiler

Abstract An industrial case history of the failure of the evaporator (water wall) tubes of a water-tube boiler is presented in this study. After two years in service, a leak was detected in one of the tubes over its bent section with pitting corrosion on its internal surface. Later on, the same symptoms were discovered in other tubes of the same boiler, and several tubes were extracted for failure analysis. On the basis of visual inspection, chemical analysis, microstructural examination, hardness measurements, and residual stress measurements via X-ray diffraction (XRD), the failure mechanism of the tubes was identified as stress corrosion cracking (SCC). In this paper, the results obtained from the experimental analysis are summarized, and finite element (FE) models are used to predict the residual stress due to the bending of the tube and the operational stress at the moment of failure. It was found that tensile residual stress from an inadequate stress relief treatment prior to service and high concentration of dissolved oxygen in the feed water were the main reasons for the premature failure of the boiler tubes by SCC.

Simulation of Working Processes in the Water-Tube Boiler Furnace with the Purpose of Reducing Emissions of Nitrogen Oxides

Simulation of Working Processes in the Water-Tube Boiler Furnace with the Purpose of Reducing Emissions of Nitrogen Oxides

Assessment of energy and exergy efficiencies in steam generators

Nowadays, more elaborate instruments are progressively required to evaluate the performance and efficiency of power plants, due to increasing concerns on climate change and the negative influence of carbon-fueled power plants on the greenhouse effect. Conventional approaches, such as mass and energy balances, result insufficient when considering solutions aimed at increasing global energy efficiency. The study presented herein focuses on the application of exergy analysis to the assessment of boilers, which are responsible for considerable exergy destruction in traditional, Rankine-based power plants. The study case considered a coal-fueled water tube boiler with 100 ton/h steam flow rate capacity. Even though exhaust gases presented high energy content, exergy analysis revealed that strategies aimed at minimizing the destruction of the capability to generate work should focus on: (1) heat transfer between exhaust gases and working fluid; and also the (2) combustion process itself. Technological advances applied to the reduction of exergy destruction in (1) and (2) are presented and discussed herein.

Analisa Efisiensi Water Tube Boiler Berbahan Bakar Fiber dan Cangkang di Palm Oil Mill Kapasitas 60 Ton TBS/Jam dengan Menggunakan Chemicalogic Steamtab Companion Version 2.0

Some of the factors that occupy the efficiency of the boiler are superheater pressure, feed water temperature, steam temperature, the amount of steam produced, the amount of fuel consumption, and the calorific value of fuel combustion. ChemicaLogic Steamtab Companion Software is software that use to calculate enthalpy value. The purpose of this research is to get the relationship of variation of superheater pressure with boiler efficiency, variation of feed water temperature with boiler efficiency, variation of steam generated with boiler efficiency, analyzing fuel calorific value of 75% fiber + 25% shell and analyzing water tube boiler. From the analysis result that has been done, the relation of variation of superheater pressure with boiler efficiency is not constant but irregular or up and down, the relation of feed water temperature variation with boiler efficiency is not constant but irregular or up and down, the relation of variation of steam produced with boiler efficiency relatively up. The highest burning calorific value (HHV) is 21078,4853 kJ/kg. The lowest burning calorific value (LHV) is 17838,4853 kJ/kg, the highest boiler efficiency value generated is 54.7% and the lowest boiler efficiency amounting to 44.23%.

Failure Mode and Effect Analysis (FMEA) for Enhancing Reliability of Water Tube Boiler in Thermal Power Plant

Failure mode and effect analysis is one of the QS-9000 quality system requirement supplements, with a wide applicability in all industrial fields. FMEA is the inductive failure analysis instruments which can be defined as a methodical group of activities intended to recognize and evaluate the potential failure modes of a product/ process and its effects with an aim to identify actions which could eliminate or reduce the chance of the potential failure before the problem occur. The purpose of this paper is to evaluate the FMEA research and application in the Thermal Power Plant Industry. The research will highlight the application of FMEA method to water tubes (WT) in boilers with an aim to find-out all the major and primary causes of boiler failure and reduce the breakdown for continuous power generation in the plant. Failure Mode and Effect Analysis technique is applied on most critical or serious parts (components) of the plant which having highest Risk Priority Number (RPN). Comparison is made between the quantitative results of FMEA and reliability field data from real tube systems. These results are discussed to establish relationships which are useful for future water tube designs.

Modelling of the aerodynamic processes of water-tube boiler DKVR(DE) -10/14

The results of numerical modeling of flow and combustion of methane with oxygen in the air in a swirling furnace plume are presented. Calculation model of oil-gas burner device GMG-7 and two-drum steam water-tube boiler DE-10-14 is built. Modelling іs carried out by сontrol volume method. The flame structure, the distribution of gas velocity in the furnace volume and aerodynamic resistance of furnace are defined. Calculations are made for heating boiler with a secondary emitter and without secondary emmiter. Figs.: 3. Table. 1. Refs.: 11 titles.Keywords: numerical modeling; flow process; steam water-tube boiler; aerodynamic resistance.

Theoretical and Numerical Analysis of Convective Recuperator for an Oil Fired Water Tube Boiler to Improve the Boiler Performance

Objectives: This paper deals with the theoretical and numerical analysis of a convective recuperator used to recover waste heat from the stack flue gases and use it to pre heat the air before it is fed into the combustion chamber of an oil fired water tube boiler. Methods/Statistical Analysis: Three different tube diameters are considered in the present study. Theoretical analysis is carried out to determine the efficiency and other parameters of the boiler with and without recuperator. To support the theoretically obtained results on improved boiler performance by pre heating the air using recuperator, numerical simulation studies is carried out. Findings: The study showed that 10” inch (0.254 m) pipe diameter arranged in a 3 x 3 array gave a flow velocity of air at around 15 to 25 m/s. The stack flue gas exit temperature decreased from 200oC to 135.50oC whereas the inlet air temperature after pre heating through the recuperator is found to be 85oC with a rise in temperature of around 50oC. After pre heating the air, the efficiency of the boiler improved from 71.90% to 74.60%. The quantity of furnace oil saved per day is 3.76% with respect to its present consumption level. CFD simulations are carried out using ANSYS CFX. A good agreement is found between the data obtained from simulation and theoretical analysis. Payback period by incorporating the recuperator to the existing boiler is estimated to be 60 working days. Application/ Improvements: Optimized performance improvement of existing boiler used in industries is possible without extensive redesign by recovering waste heat leading to energy conservation.

Catalytic Air Pollution Control: Commercial Technology

Fouling is a topic of interest in almost all heat production systems. A noticeable fall in thermal efficiency can be caused by accumulated fouled matter, especially in those surfaces where heat exchange takes place. In this research, two domestic-scale commercial pellet boilers were studied (a 24 kW water-tube boiler-stove and a 60 kW fire-tube boiler). Sampling probes were placed in both heat exchangers to measure the deposition rate. Commercial wood pellets were used as fuel. A series of tests were carried out under the same operating conditions. Average fouling rates (FR) of 7–12 g/m2h in the water-tube boiler-stove and 3–5 g/m2h in the fire-tube boiler were measured. The variation of these fouling rates with the position in the boiler side was also analyzed. In addition, measurements of the particulate matter (PM) concentration and flue gas composition were made during the tests. A correlation between the CO emissions and the collected solid particulate (SP) matter was obtained for each case of study. PM values of 110–280 mg/Nm3 were measured for the water-tube boiler and 13–135 mg/Nm3 for the fire-tube boiler. An SP size distribution study provided evidence for the large amount of ultrafine particles in domestic biomass combustion systems.

Numerical simulation of a 374 tons/h water-tube steam boiler following a feedwater line break

To ensure the operational safety of an industrial water-tube steam boiler it is very important to assess various accident scenarios in real plant working conditions. One of the most challenging scenarios is the loss of feedwater to the steam boiler. In this paper, a simulation of the behavior of an industrial water-tube radiant steam boiler during feedwater line break accident is discussed. The simulation is carried out using the RELAP5 system code. The steam boiler is installed in an Algerian natural gas liquefaction complex. The simulation shows the capabilities of RELAP5 system code in predicting the behavior of the steam boiler at both steady state and transient working conditions. From another side, the behavior of the steam boiler following the accident shows how the control system can successfully mitigate the effects and consequences of such accident and how the evaporator tubes can undergo a severe damage due to an uncontrolled increase of the wall temperature in case of failure of this system.

Experimental analysis of fouling rates in two small-scale domestic boilers

Fouling is a topic of interest in almost all heat production systems. A noticeable fall in thermal efficiency can be caused by accumulated fouled matter, especially in those surfaces where heat exchange takes place. In this research, two domestic-scale commercial pellet boilers were studied (a 24 kW water-tube boiler-stove and a 60 kW fire-tube boiler). Sampling probes were placed in both heat exchangers to measure the deposition rate. Commercial wood pellets were used as fuel. A series of tests were carried out under the same operating conditions. Average fouling rates (FR) of 7–12 g/m2h in the water-tube boiler-stove and 3–5 g/m2h in the fire-tube boiler were measured. The variation of these fouling rates with the position in the boiler side was also analyzed. In addition, measurements of the particulate matter (PM) concentration and flue gas composition were made during the tests. A correlation between the CO emissions and the collected solid particulate (SP) matter was obtained for each case of study. PM values of 110–280 mg/Nm3 were measured for the water-tube boiler and 13–135 mg/Nm3 for the fire-tube boiler. An SP size distribution study provided evidence for the large amount of ultrafine particles in domestic biomass combustion systems.

English

The aim of this study was to carry out an economic and financial evaluation of the use of a dryer column with steam system replacing a conventional furnace. Seeking an energetic and economic evaluation of the process of grain drying, a research was carried out on the drying of corn kernels using a dryer column (Comil CM 150 DR, double reuse) and a water-tube boiler (CW 40). In order to perform economic and financial analysis, the net present value (VPL), internal rate of return (TIR), profitability index (PI), rate of return (RR) and discounted payback were calculated. In the economic analysis, an investment of US$ 155,258.84 and a minimum acceptable rate of return (MARR) of 3.5% per year were considered. The VPL within 15 years was US$ 200,612.85. The TIR was 17.89% per year. The project presented a PI of 1.29% and RR of 29%, which were considered acceptable. The payback period, considered as the time required to recover the capital invested in the project was 7 years, which indicates economic feasibility. Key words: Energy, firewood, storage.

Screening and Quantification of Aliphatic Primary Alkyl Corrosion Inhibitor Amines in Water Samples by Paper Spray Mass Spectrometry.

Direct analysis and identification of long chain aliphatic primary diamine Duomeen O (n-oleyl-1,3-diaminopropane), corrosion inhibitor in raw water samples taken from a large medium pressure water tube boiler plant water samples at low LODs (<0.1 pg) has been demonstrated for the first time, without any sample preparation using paper spray mass spectrometry (PS-MS). The presence of Duomeen O in water samples was confirmed via tandem mass spectrometry using collision-induced dissociation and supported by exact mass measurement and reactive paper spray experiments using an LTQ Orbitrap Exactive instrument. Data shown herein indicate that paper spray ambient ionization can be readily used as a rapid and robust method for in situ direct analysis of polymanine corrosion inhibitors in an industrial water boiler plant and other related samples in the water treatment industry. This approach was applied for the analysis of three complex water samples including feedwater, condensate water, and boiler water, all collected from large medium pressure (MP) water tube boiler plants, known to be dosed with varying amounts of polyamine and amine corrosion inhibitor components. Polyamine chemistry is widely used for example in large high pressure (HP) boilers operating in municipal waste and recycling facilities to prevent corrosion of metals. The samples used in this study are from such a facility in Coventry waste treatment facility, U.K., which has 3 × 40 tonne/hour boilers operating at 17.5 bar.

小型貫流ボイラの歴史と機械遺産 ZP ボイラ

小型貫流ボイラの歴史と機械遺産 ZP ボイラ

Remaining Creep Life Assessment of Service Superheat Tube Boiler

The demand of remaining life assessment of the boilers arises from technical, economic, and legal reasons. Creep is major damage mechanism of primary superheat tube boiler during prolong operation at high temperature and pressure in a water tube boiler. This paper presents the calculation method for the remaining life assessment due to creep damage. The service-exposed primary superheat tube made of 2.25Cr-1Mo steels. During scheduled inspection, wall thickness measurement, metallographic investigation by replica technique, design data and operating condition were used to estimate the remaining life in the form of creep damage accumulation rate calculated from life fraction using Larson-Miller Parameter. The results indicate that the primary superheat tubes satisfy in extension service life. By attaining an accurate and timely discussion of the results, the engineer can manage the maintenance and inspection schedule for the critical part in the boiler.