Failure of Boilers and Related Equipment

2021 ◽  
pp. 662-694
Author(s):  
Paresh Haribhakti ◽  
P.B. Joshi
Keyword(s):  
Power Plants ◽  
Fossil Fuels ◽  
General Procedure ◽  
Rankine Cycle ◽  
Damage Mechanism ◽  
Working Fluid ◽  
Representative Case ◽  
Failure Investigation ◽  
Boiler Tubes ◽  
Cycle Systems

Abstract Failures in boilers and other equipment taking place in power plants that use steam as the working fluid are discussed in this article. The discussion is mainly concerned with failures in Rankine cycle systems that use fossil fuels as the primary heat source. The general procedure and techniques followed in failure investigation of boilers and related equipment are discussed. The article is framed with an objective to provide systematic information on various damage mechanisms leading to the failure of boiler tubes, headers, and drums, supplemented by representative case studies for a greater understanding of the respective damage mechanism.

scholarly journals Performance modelling and greenhouse impact assessment of a micro-ORC energy system working with HFCs, low GWP fluids and mixtures

2021 ◽  
Vol 238 ◽  
pp. 10002
Author(s):  
Michele Bianchi ◽  
Lisa Branchini ◽  
Andrea De Pascale ◽  
Francesco Melino ◽  
Saverio Ottaviano ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Energy System ◽  
Working Fluid ◽  
Performance Modelling ◽  
Cycle Systems ◽  
Greenhouse Impact ◽  
Greenhouse Emission ◽  
Fluid Leak

The worrying effects of climate change have led, in the last decades, to the improvement of innovative solutions for low greenhouse emission energy conversion, among which, is the use of micro-ORC (Organic Rankine Cycle) systems for distributed generation, in the framework of combined heat and power applications and renewables exploitation. However, micro-ORCs environmental impact, due to high GWP (global working potential) working fluid leak rate, is an issue still to overcome. Neverthless the interest in using new low GWP refrigerants and their blends is increasing, new fluids have not yet been properly tested into ORC. Numerical studies reveal that low GWP fluids do not always guarantee the same performance of typically used fluids, leading to indirect emissions related to the use of fossil fuels to compensate the lower power production. This study proposes to investigate performance and impact of an innovative micro-ORC test bench when working with HFCs (HydroFluoroCarbons), low GWP fluids and mixtures, with the main aim of comprehensively evaluating its impact due to both direct and indirect greenhouse gas emissions produced in a typical annual operation.

Development of the Trilateral Flash Cycle System: Part 1: Fundamental Considerations

1993 ◽  
Vol 207 (3) ◽  
pp. 179-194 ◽  
Author(s):  
I K Smith
Keyword(s):  
Power Systems ◽  
Power Plants ◽  
Rankine Cycle ◽  
World Market ◽  
Low Grade ◽  
Heat Sources ◽  
Two Phase ◽  
Cycle System ◽  
Cycle Systems ◽  
Power Recovery

The world market for systems for power recovery from low-grade heat sources is of the order of £1 billion per annum. Many of these sources are hot liquids or gases from which conventional power systems convert less than 2.5 per cent of the available heat into useful power when the fluid is initially at a temperature of 100° C rising to 8–9 per cent at an initial temperature of 200°C. Consideration of the maximum work recoverable from such single-phase heat sources leads to the concept of an ideal trilateral cycle as the optimum means of power recovery. The trilateral flash cycle (TFC) system is one means of approaching this ideal which involves liquid heating only and two-phase expansion of vapour. Previous work related to this is reviewed and details of analytical studies are given which compare such a system with various types of simple Rankine cycle. It is shown that provided two-phase expanders can be made to attain adiabatic efficiencies of more than 75 per cent, the TFC system can produce outputs of up to 80 per cent more than simple Rankine cycle systems in the recovery of power from hot liquid streams in the 100–200°C temperature range. The estimated cost per unit net output is approximately equal to that of Rankine cycle systems. The preferred working fluids for TFC power plants are light hydrocarbons.

Calculation and Optimization of Heat Transfer between the Low Exergy Heat Source and Organic Rankine Cycle Applied to Heat Recovery Systems

2013 ◽  
Vol 597 ◽  
pp. 45-50
Author(s):  
Sławomir Smoleń ◽  
Hendrik Boertz
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Heat Recovery ◽  
Power Plants ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Optimization Procedure ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Total System

One of the key challenges on the area of energy engineering is the system development for increasing the efficiency of primary energy conversion and use. An effective and important measure suitable for improving efficiencies of existing applications and allowing the extraction of energy from previously unsuitable sources is the Organic Rankine Cycle. Applications based on this cycle allow the use of low temperature energy sources such as waste heat from industrial applications, geothermal sources, biomass, fired power plants and micro combined heat and power systems.Working fluid selection is a major step in designing heat recovery systems based on the Organic Rankine Cycle. Within the framework of the previous original study a special tool has been elaborated in order to compare the influence of different working fluids on performance of an ORC heat recovery power plant installation. A database of a number of organic fluids has been developed. The elaborated tool should create a support by choosing an optimal working fluid for special applications and become a part of a bigger optimization procedure by different frame conditions. The main sorting criterion for the fluids is the system efficiency (resulting from the thermo-physical characteristics) and beyond that the date base contains additional information and criteria, which have to be taken into account, like environmental characteristics for safety and practical considerations.The presented work focuses on the calculation and optimization procedure related to the coupling heat source – ORC cycle. This interface is (or can be) a big source of energy but especially exergy losses. That is why the optimization of the heat transfer between the heat source and the process is (besides the ORC efficiency) of essential importance for the total system efficiency.Within the presented work the general calculation approach and some representative calculation results have been given. This procedure is a part of a complex procedure and program for Working Fluid Selection for Organic Rankine Cycle Applied to Heat Recovery Systems.

Analytical Formulation of the Performance of the Allam Power Cycle

2020 ◽  
Author(s):  
Yousef Haseli
Keyword(s):  
Power Plants ◽  
Fossil Fuels ◽  
Air Separation ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Separation Unit ◽  
Power Cycle ◽  
Functional Relationships ◽  
Oxyfuel Combustion ◽  
Co2 Flow

Abstract Thermal power plants operating on fossil fuels emit a considerable amount of polluting gases including carbon dioxide and nitrogen oxides. Several technologies have been developed or under development to avoid the emissions of, mainly, CO2 that are formed as a result of air-fuel combustion. While post-combustion capture methods are viable solutions for reduction of CO2 in the existing power plants, implementation of the concept of oxyfuel combustion in future power cycles appears to be a promising technique for clean power generation from fossil fuels. A novel power cycle that employs oxyfuel combustion method has been developed by NET Power. Known as the Allam cycle, it includes a turbine, an air separation unit (ASU), a combustor, a recuperator, a water separator, CO2 compression with intercooling and CO2 pump. (Over 90% of the supercritical CO2 flow is recycled back to the cycle as the working fluid, and the rest is extracted for further processing and storage. The present paper introduces a simplified thermodynamic analysis of the Allam power cycle. Analytical expressions are derived for the net power output, optimum turbine inlet temperature (TIT), and the molar flowrate of the recycled CO2 flow. The study aims to provide a theoretical framework to help understand the functional relationships between the various operating parameters of the cycle. The optimum TIT predicted by the presented expression is 1473 K which is fairly close to that reported by the cycle developers.

Application of Supercritical Fluids in Thermal- and Nuclear-Power Engineering

2021 ◽  
pp. 601-658
Author(s):  
Igor L. Pioro
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Supercritical Fluids ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Thermal Power Plants ◽  
Power Cycles

Supercritical Fluids (SCFs) have unique thermophyscial properties and heat-transfer characteristics, which make them very attractive for use in power industry. In this chapter, specifics of thermophysical properties and heat transfer of SCFs such as water, carbon dioxide, and helium are considered and discussed. Also, particularities of heat transfer at Supercritical Pressures (SCPs) are presented, and the most accurate heat-transfer correlations are listed. Supercritical Water (SCW) is widely used as the working fluid in the SCP Rankine “steam”-turbine cycle in fossil-fuel thermal power plants. This increase in thermal efficiency is possible by application of high-temperature reactors and power cycles. Currently, six concepts of Generation-IV reactors are being developed, with coolant outlet temperatures of 500°C~1000°C. SCFs will be used as coolants (helium in GFRs and VHTRs, and SCW in SCWRs) and/or working fluids in power cycles (helium, mixture of nitrogen (80%) and helium (20%), nitrogen and carbon dioxide in Brayton gas-turbine cycles, and SCW/“steam” in Rankine cycle).

Effects of Various Types of Binary Cycles on Thermal and Exergy Efficiency of Combined Flash-Binary Power Plants

2012 ◽  
Author(s):  
Mahshid Vatani ◽  
Masoud Ziabasharhagh ◽  
Shayan Amiri
Keyword(s):  
Power Plants ◽  
Organic Rankine Cycle ◽  
Internal Heat ◽  
Rankine Cycle ◽  
Exergy Efficiency ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Internal Heat Exchanger ◽  
Different Types ◽  
Geothermal Power

With the progress of technologies, engineers try to evaluate new and applicable ways to get high possible amount of energy from renewable resources, especially in geothermal power plants. One of the newest techniques is combining different types of geothermal cycles to decrease wastage of the energy. In the present article, thermodynamic optimization of different flash-binary geothermal power plants is studied to get maximum efficiency. The cycles studied in this paper are single and double flash-binary geothermal power plants of basic Organic Rankine Cycle (ORC), regenerative ORC and ORC with an Internal Heat Exchanger (IHE). The main gain due to using various types of ORC cycles is to determine the best and efficient type of the Rankine cycle for combined flash-binary geothermal power plants. Furthermore, in binary cycles choosing the best and practical working fluid is an important factor. Hence three different types of working fluids have been used to find the best one that gives maximum thermal and exergy efficiency of combined flash-binary geothermal power plants. According to results, the maximum thermal and exergy efficiencies both achieved in ORC with an IHE and the effective working fluid is R123.

Concepts and Experiences for Higher Plant Efficiency With Modern Advanced Boiler and Incineration Technology

2010 ◽  
Author(s):  
Armin Main ◽  
Thomas Maghon
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Fossil Fuels ◽  
Live Steam ◽  
Gas Temperature ◽  
Higher Plant ◽  
Advantages And Disadvantages ◽  
Boiler Tubes ◽  
Steam Parameters ◽  
Plant Efficiency

The efforts for reducing CO2 Emissions into atmosphere and increasing costs for fossil fuels concepts are the drivers for Energy from Waste (EfW) facilities with higher plant efficiency. In the past steam parameters for EfW were requested mainly at 40 bars and 400 °C (580 psi and 752 F). In case of coal fired power plants at the same location as the EfW facilities higher steam parameters at 90 bar, 520 °C (1305 psi, 968 F) have been used for the design of stoker and boiler. This long-term experience with higher steam parameters is the platform for the todays and future demand in higher plant efficiency. Increase in EfW plant efficiency is achievable by increasing temperature and pressure of live steam going along with optimized combustion conditions when using well proven grate technology for waste incineration. On the other hand higher steam parameters result in higher corrosion rates on the boiler tubes and the optimization of the combustion conditions are limited by the burn out quality requirements of slag and flue gas. Advantages and disadvantages have therefore to be balanced carefully. This paper will present different measures for optimized boiler and combustion conditions compared to an EfW plant with live steam at 40 bars and 400 °C (580 psi and 752 F) and 60% excess of combustion air. Plants operated at these conditions have very low maintenance costs created by corrosion of boiler tubes and show performance with very high availability. The following parameters and experiences will be evaluated: - reduction of excess air; - flue gas temperature at boiler outlet; - higher steam parameters (pressure and temperature); - heating surfaces for steam superheating in the radiation boiler section; - steam reheating; - external superheaters using auxiliary fuels. The comparison of the different methods for increasing the efficiency together with resulting technology challenges incorporates the experiences from modern EfW reference facilities built in Naples/Italy, Ruedersdorf (Berlin)/Germany and Heringen/Germany.

Numerical Simulation of Real-Gas Flow in a Supersonic Turbine Nozzle Ring

2002 ◽  
Vol 124 (2) ◽  
pp. 395-403 ◽  
Author(s):  
J. Hoffren ◽  
T. Talonpoika ◽  
J. Larjola ◽  
T. Siikonen
Keyword(s):  
Power Plants ◽  
Gas Flow ◽  
Cfd Simulation ◽  
Low Cost ◽  
Design Procedure ◽  
Rankine Cycle ◽  
Simulation Method ◽  
Ideal Gas ◽  
Working Fluid ◽  
Real Gas

In small Rankine cycle power plants, it is advantageous to use organic media as the working fluid. A low-cost single-stage turbine design together with the high molecular weight of the fluid leads to high Mach numbers in the turbine. Turbine efficiency can be improved significantly by using an iterative design procedure based on an accurate CFD simulation of the flow. For this purpose, an existing Navier-Stokes solver is tailored for real gas, because the expansion of an organic fluid cannot be described with ideal gas equations. The proposed simulation method is applied for the calculation of supersonic flow in a turbine stator. The main contribution of the paper is to demonstrate how a typical ideal-gas CFD code can be adapted for real gases in a very general, fast, and robust manner.

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