Heat Recovery Boiler Research Articles

Optimal configuration of low‐grade waste heat driven seawater desalination using data envelopment analysis: A case study of industrial application

AbstractWater supply challenges are caused by population growth, industrialization, as well as the scarcity of freshwater resources. Low‐grade waste heat‐driven seawater desalination technologies may improve the water‐energy nexus issues of desalination systems by different configurations. The data envelopment analysis is used to determine the best final decision to achieve a better comparison of different parameters. The optimal configuration of low‐grade waste heat driven seawater desalination is studied using flue gas waste heat in heat recovery boilers of an industrial oil refinery. Nine different types of multistage flash and multi‐effect distillation (MED) desalination plants have been considered. The results show that the multistage flash brine recirculation may produce more desalinated water while the multi‐effect distillation with three stages (3‐stage MED) has the best payback period. Using 3‐stage MED with a production of approximately 19,630 kg/h of water from 5.3 MW exhaust gas is more suitable for this design. Thus, the proposed strategy guides us toward the best decisions to configure low‐grade waste heat‐driven desalination plants for better design considering rigorous simulations for the plants. Moreover, this framework enables us to consider different criteria of technical, economic, and environmental issues for optimal configuration.

Thermodynamic Optimization of Trigeneration Power System

Worldwide, the growing demand for energy has been largely met through power cycles utilizing fossil fuels. Combined cycles, which integrate a gas turbine with a steam cycle, prove to be the best alternative due to their power generation capacity and high efficiencies. This efficiency is primarily attributed to the ability to harness exhaust gases to generate steam in the heat recovery boiler, allowing additional power generation through the steam turbine. Currently, there is a quest for the integration of low-temperature power cycles to maximize the utilization of residual thermal energy flows for power generation. Therefore, this work conducts an exergetic optimization of a power trigeneration system aimed at maximizing exergetic efficiency. This system includes a gas turbine and a steam cycle coupled with three different configurations of the Organic Rankine Cycle (ORC): a simple ORC, a supercritical ORC, and an ultracritical ORC. The ORC configurations are analyzed using eight organic working fluids, namely R1234yf, R290, R134a, R1234ze, R152a, R600a, R245fa, and R123. The results show that the maximum exergetic efficiency is achieved by using R152a in the ultracritical ORC configuration coupled with the combined cycle, achieving an exergetic efficiency of 55.79%. Furthermore, the maximum power generated is attained by the steam cycle with 85,600.63 kW and 3101.21 kW for the ultracritical ORC.

Heat transfer characteristics of a heat-recovery boiler built based on a modular mini boiler

The objective of this study is to design a heat-recovery boiler for a 1 MW-class gas engine-based cogeneration system intended to recover heat from engine exhaust gas. To accommodate high-pressure applications, a water tube-type boiler is selected. For ensuring effective water circulation within the boiler, an innovative modular-type boiler based on the mini-boiler concept is developed. This boiler comprises finned tube-type risers, and their heat-transfer characteristics are measured and compared with the conventional correlation used in the design process. Additionally, an inlet guide vane is developed to address the temperature nonuniformity resulting from the shape mismatch between the gas engine outlet and heat-recovery boiler inlet. The performance of the proposed boiler was evaluated by integrating it into an experimental rig. The diamond-shaped inlet guide vane, which was designed by computational fluid dynamics, facilitated a uniform temperature distribution. However, the temperature became nonuniform downstream owing to the influence of a downcomer. Although the modular heat-recovery boiler effectively produced steam from gas engine exhaust gasses, its heat-transfer performance in the downstream section was lower than expected, necessitating additional heat-transfer area.

Active Disturbance Rejection Control Design with Sensitivity Constraint for Drum Water Level

The drum water level plays a crucial role in the safety and economy of heat recovery boilers. However, the control of the drum water level faces many challenges, such as external disturbances and system uncertainties. To enhance the control performance of the drum water level, a modified active disturbance rejection control (MADRC) optimized with sensitivity constraint is proposed in this paper. Firstly, the control structure of the three-element control system for the drum water level is introduced and analyzed. Based on the regular active disturbance rejection control (ADRC) structure, the structure of the MADRC is introduced and the convergence of the proposed MADRC is proven. Then a modified whale optimization algorithm (MWOA) with sensitivity constraint is applied to optimize the parameters of the MADRC. With different sensitivity constraints, the parameters of the MADRC and comparative controllers are obtained, and their control performance for tracking and disturbance rejection abilities is compared. Moreover, the ability to handle system uncertainties is analyzed. Simulation results and performance indexes show that the proposed MADRC can obtain the best tracking and disturbance rejection abilities with satisfactory robustness. The satisfactory control performance shows that the proposed MADRC has wide application potential for heat recovery boilers and other industrial processes.

Transformation and environmental chemical characteristics of hazardous trace elements in an 800 t/d waste incineration thermal power plant

The hazardous trace elements (HTEs) emitted during the municipal solid waste incineration (MSWI) process have been widely concerned. In this work, the bottom ash (BA), heat recovery boiler ash (HA), and ash after desulfurization (SA) were collected to explore the occurrence forms of HTEs in the three types of ash and their relationship with minerals and leaching characteristics. The results show that the volatility of the seven studied HTEs follows the order of Cd, As > Ni, Zn > Pb > Cr, Cu. In the process of BA → HA → SA, the content of Cd, As, Zn, and Pb shows an increasing trend. The seven HTEs are mainly in the forms of chlorides and oxides. There is an obvious relationship between the occurrence forms and simulated existence form of HTEs. SiO2 and CaCO3 are the major mineral components in the three ashes, while SA also contains chlorine-containing compounds which are easily leached out. The risk assessment code and soluble ratio show that HTEs in SA are more leachable than BA and HA, where Cd, Pb and Ni need to be addressed to reduce their impact on soil or water during subsequent landfill treatment of SA.

Multi-objective optimization of micro-gas turbine coupled with LCPV/T combined cooling, heating and power (CCHP) system based on following electric load strategy

A distributed energy system integrated with solar and natural gas can achieve cascade energy utilization, high efficiency and energy-saving, and significantly reduce carbon emissions, which is receiving increasing attention. Therefore, this paper establishes an optimization model for primary energy consumption saving rate (PECSR), annual total cost saving rate (ATCSR), carbon dioxide emission reduction rate (CDERR) and exergy efficiency of micro-gas turbine coupled with low-concentrating photovoltaic/thermal (LCPV/T) CCHP system, and analyzes the influence of the parameters, such as solar irradiation, LCPV/T inlet temperature, LCPV/T inlet flow, LCPV/T area, low-temperature water source heat pump capacity, high-temperature water source heat pump capacity, the heat transfer efficiency of waste heat recovery boiler (WHRB) and gas boiler capacity, on the objective functions. The analysis results indicate that when the heat exchange efficiency of WHRB reaches 0.71, the CCHP system is most economical. Based on this, the Strength Pareto Evolutionary Algorithm-II (SPEA-II) optimization algorithm and decision-making method combining Technique for order preference by similarity to an ideal solution (TOPSIS) and weight entropy method are employed to solve the model comprehensively, and acquire the optimum solution. After multi-objective optimization and selection, the system exergy efficiency remains around 25 %. Compared with the separation production system, the PECSR and CDERR of the CCHP system are improved by more than 24 % and 41 %, respectively.

EVALUACIÓN DE ALTERNATIVAS TECNOLÓGICAS PARA EL APROVECHAMIENTO ENERGÉTICO DEL BIOGÁS GENERADO A PARTIR DE RESIDUOS PORCINOS

This work integrated in a process simulation, the anaerobic digestion of swine slurry and three technological alternatives for the energetic use of biogas. In addition, the energy yield and technical-economic feasibility were evaluated under different swine population scenarios in Cuba. Aspen Plus v12.0 was used to incorporate the alternatives analyzed: steam generator, internal combustion engine and heat recovery boiler. The results of the study indicated energy efficiencies between 79%-85%, TIR between 36%-43%, VAN between 2578818.80$-1975810.72$, with a PRD between 2.8 and 3.5 years. The profitability of the project was found to be most sensitive to the variation in the scenarios of pig population per alternative, with scenario 4 being the most profitable. The study provides important insights into the use of this renewable energy sources in rural areas, with a focus on environmental sustainability. Key Words: Biogas, energy efficiency, Aspen modelling, economic analysis.

Tribo-mechanical characterization of Cu-Cr-Zr ternary alloy aimed at fin-tube resistance welding electrode material

PurposeLow performance life and increased machine downtime due to wear of resistance welding copper electrode is of major concern in fin–tube resistance welding in waste heat recovery boilers. The purpose of this study is to investigate an alternative material with good wear resistance to replace the currently utilized C11000 electrolytic tough pitch (ETP) copper electrode.Design/methodology/approachIn this study, a Cu-Cr-Zr ternary alloy was developed for fin-to-tube welding electrode by melting commercial grade electrolytic copper (99.9% purity) plates, chips of chromium, powder of zirconium at 1100°–1300°C, followed by hot forging and precipitation hardening at 450°–550°C to attain appropriate grain flow. Microstructures of Cu-Cr-Zr alloys were analysed using scanning electron microscopy coupled with energy-dispersive backscatter electron spectrometry.FindingsWear performance of Cu-Cr-Zr and C11000 ETP Cu was evaluated using pin-on-disc set-up with Taguchi’s L8 orthogonal array. Ranking of the parameters was done, and it was observed that the material and temperature play a very significant role in controlling the wear of an electrode.Practical implicationsRate of fin–tube resistance welding was increased by 26% with Cu-Cr-Zr alloy. Further investigation on effect of plasma on the metallurgical characteristics of Cu-Cr-Zr is recommended.Originality/valueTribo-mechanical performance of newly developed Cu-Cr-Zr ternary alloy was compared with C11000 ETP copper.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2023-0092/

Optimization of a CHP system using a forecasting dispatch and teaching-learning-based optimization algorithm

Using optimization algorithms and developing dispatch strategies are essential in sizing renewable energy systems to ensure optimal performance, cost-effectiveness, and sustainability. This study employs the Teaching-Learning-based Optimization (TLBO) algorithm to determine the optimal size of a Combined Heat and Power (CHP) system. The optimization results are validated using the Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). Furthermore, a novel dispatch strategy is developed to make an informed decision when using different energy sources. The strategy considers a 24-h foresight of upcoming electrical demand, solar irradiation, temperature, and wind speed. The developed dispatch strategy has led to a reduction in cost and excess electricity compared to the pre-prepared strategies. The energy sources employed include Photovoltaic panels (PV), Wind Turbines (WT), Diesel Generators (DG) with heat recovery capability, battery banks, and boilers to supply electrical and thermal demand. A Levelized cost of energy (LCOE) of 0.142 $/kWh is obtained for the PV/WT/DG/Battery/Boiler system. Although the three algorithms find almost similar optimal solutions, TLBO exhibits better convergence speed than PSO and GA. A comparison with HOMER software control strategies shows the developed dispatch strategy is 3.4% and 15.5% more efficient than Cycle Charging and Load Following strategies, respectively. Lastly, a comprehensive economic sensitivity analysis is performed to investigate the effect of inflation and discount rates on the size of components and final objective functions.

Water-energy nexus in the combined cycle power plant using energy, exergy, economic and environmental analyses

The growing demand for water and energy and the limitation on their resources necessitate comprehensive studies on the water-energy nexus from different aspects in large industries, especially power plants. In the present study, the water-energy nexus has been analyzed using energy, exergy, economic, and environmental analyses for the retrofit scenarios in a combined cycle power plant. The injection of boiler blow-down into the condenser will save 47809.5 m3 of make-up water and 1.115 million m3 of natural gas per year. Replacing the Maisotsenko evaporative cooler with the fogging system increases the revenue index and the water consumption index by 2.7%. The raw water is replaced with high-quality water. The output power of the combined cycle power plant is reduced by 2.1 MW (0.83%) due to the steam injection from the heat recovery boiler into the combustion chamber of the gas unit, while its exergy degradation rate is reduced by 8.5 MW (2.42%). Also, the efficiency of the first and second laws have been decreased by 0.49% and 0.4%, respectively. The results show that the recovery of boiler blow-down for condenser or steam injection into the combustion chamber of the gas unit from heat recovery of the boiler reduces water consumption and exergy destruction simultaneously. Using Maisotsenko cycle and steam injection into the combustion chamber of the gas unit from the heat recovery of boiler reduces the exergy destruction and NOx emissions. The present study provides useful insights to quantify the water-energy nexus for decision-makers in the industry to reach proper decisions according to the opportunities and limitations.

Improving the efficiency of energy saving through the use of thermal energy

The article analyzes the problem of energy saving in the context of organizational and technical measures. One of the energy saving factors is the use of waste heat of various potential. The advantages of using waste heat in the energy sector and the scope of their application are considered. Power plants for waste processing and their parameters are described. Examples of the creation of special energy devices for the chemical industry are given. The connection of internal (by-product) energy resources (IER) with technologies using melting furnaces is noted. The boundaries of the use of heat recovery boilers (HRB) in various industries are determined. The schemes of HRB application at the wastewater disposal site with quantitative and qualitative characteristics are given. A method for improving economizers using bimetallic pipes and heat exchangers is given. The use of batteries in the disposal and consumption of waste heat is justified. The ways of increasing the efficiency of compressed air systems and the features of using arc steelmaking furnaces to reduce energy consumption are considered. The comparison of local heat supply schemes with regenerative ones is carried out and the prospects for the development of these schemes are noted.

Optimized Operation of Park-level Integrated Energy System Based on Particle Swarm Optimization with Curve Increasing

In the traditional park, the electric energy is completely provided by the power grid, in addition, the thermal energy is provided by the gas boiler. The single energy structure leads to higher operating cost and lower energy utilization rate of the park. Therefore, firstly, a park-level integrated energy system composed of gas turbine, heat recovery boiler, gas boiler, storage battery, and the load of heat and power has been proposed in this composition. Secondly, considering time-sharing tariff and the randomness of load, the objective function is established with the minimum daily operation cost as the optimization aim. Then, a particle swarm optimization with curve increasing strategy is proposed to solve the objective function. Finally, the load data of a typical day in winter is analyzed as an example. The simulation results show that the proposed method can optimize the energy structure of the park, improve the economy of the system operation, and reduce the daily operation cost of the system by 12.32%.

Cogeneration potential of an operating diesel engine power plant

Waste heat recovery systems convert the thermal energy in waste fluid streams into useful work. Diesel engine cogeneration systems are waste recovery systems using technologies and devices with main elements being the diesel engine prime movers, the electric generator, Rankine cycle steam turbine, exhaust heat recovery boiler super heaters, and control and instrumentation devices. Diesel engines exhaust significant recoverable heat energy that can be converted to extra electricity using a Rankine cycle plant. In this study, the cogeneration potential of an operating diesel engine power plant was established. The cogeneration potential of a 119.7 MW operating power plant in Kenya is established. The study showed that subject to limits imposed by presence of sulphur in fuel and hence existence of sulphur dioxide in the exhaust, each engine of capacity 17.1 MWe has recoverable thermal energy of about 1.33 MWth while the whole plant with seven engines is about 9.3 MWth for the 7 engines at plant optimum loading conditions which can generate 8.5 MWe extra electricity under optimum conditions. The study recommends the development of up to 9 MWe Rankine cycle steam turbine-based cogeneration power plant. Diesel power plant cogeneration is a technically and economically viable strategy to increase the generation efficiency of diesel power plants and reduce the pollution intensity and financial performance of the diesel power plant leading to reduction in cost of power and higher return on investment for investors.

MAINTAINING DECLARED PERFORMANCE IN GAS TURBINES DURING INCREASED AMBIENT TEMPERATURES

The classical gas turbine process is characterised by air compression from its surroundings, heating fuel in the combustion chambers, hence causing the created flue gases to expand in the turbine and thus induce mechanical action. The performance of gas turbine depends on anything that affects the airflow density and/or mass at the compressor inlet. The most obvious changes in gas turbine performance is a reduction in power and an increase in specific fuel consumption following an increase in the ambient temperature, resulting in significant deviations of the guaranteed (and achieved) values at ISO conditions. In cooling air at the compressor inlet at increased ambient temperatures, an increase in the mass flow and compression ratio is achieved, thus preventing a reduction in power and an increase in specific fuel consumption. When using gas turbines in combined cycle cogeneration power plants for the production of electrical and thermal power, increasing mass flow through gas turbines leads to an increase in power transferred by the flue gases to the turbine exhaust, and which in the waste heat recovery boiler at the combined cycle plant transfers to the steam turbine cycle. Consequently, the effect at the combined cycle plant is a more significant reduction in specific fuel consumption. The work has used the example of the GE-PG610FA turbine to show the dependency on surrounding climatic conditions, and the manner in which this dependency can be reduced or removed.

A thermodynamic model for high temperature corrosion applications: The (Na2SO4 + K2SO4 + ZnSO4 + PbSO4) system

The (Na2SO4 + K2SO4 + ZnSO4 + PbSO4) salt system is important for deposit buildup, fouling and associated corrosion of metallic structural and heat exchanger materials of municipal solid waste incinerators, low-grade fuel firing boilers, as well as metallurgical heat recovery boilers. In this study, a complete critical evaluation of all available phase diagram and thermodynamic data has been performed for all condensed phases of the (Na2SO4 + K2SO4 + ZnSO4 + PbSO4) system, and optimized model parameters have been found. The Modified Quasichemical Model for short-range ordering was used for the molten salt phase while most of the relevant solid solutions were modeled using the Compound Energy Formalism. The (Na2SO4 + K2SO4) sub-system has been critically evaluated in a previous article. A (60 mol% PbSO4 + 40 mol% ZnSO4) binary mixture was investigated by DTA-TGA since no thermodynamic data were available in the literature for this particular sub-system. The model parameters obtained for the binary and ternary sub-systems of the (Na2SO4 + K2SO4 + ZnSO4 + PbSO4) system can be used to predict thermodynamic properties and phase equilibria for the multicomponent system. In particular, ternary and quaternary eutectics (corresponding to the formation of a liquid phase at low temperatures) may be predicted, thus permitting to avoid “catastrophic” corrosion. This work is part of a large thermodynamic model for the Na+, K+, Zn2+, Pb2+ // Cl−, SO42− system.

Modeling the prediction of water and steam quality in a power unit

In this article, mathematical models based on the material balance equations for the drums of the low and high pressure circuit of the heat recovery boiler are compiled. Investigated impurities: sodium, silica, iron. For the equation for the concentration of iron, the coefficients of the rate of formation and flushing of deposits proposed by the authors are taken into account. The concentrations of impurities obtained according to the developed models in controlled streams were studied: feed and boiler water, saturated steam. The calculation results are compared with industrial data. It was found that the error does not exceed 20%, which confirms the possibility of using the developed mathematical models in cycle chemistry. These algorithms reduce the volume of measured water and steam quality indicators and facilitate the work of operational personnel.

A heat recovery boiler as part of a multi-purpose reseach bench based on an engine 2CH 10.5/13

The issues of development and creation of a multi-purpose stand based on the 2СH 10.5/13 engine are considered. The main areas of experimental research at this stand are: utilization of exhaust gas heat, ways to reduce emissions of harmful substances from engine exhaust gases, optimization of engine system parameters, the use of various fuels in internal combustion engines, including water-fuel emulsions and biofuels, control of the working process in the cylinder and torque measurement. It is emphasized that these directions do not exhaust the possibilities of the stand. The measures for the modernization of the engine and stand systems are considered: air supply and gas outlet, fuel and cooling. It is shown that in order to control the parameters of the stand, a measuring complex is needed that allows continuously measuring a large number of parameters, performing their processing, displaying, archiving and transferring to a computer that controls the operation of the stand.

Selection, Calculation and Thermodynamic Analysis of Turbine Units Based on the Organic Rankine Cycle

A program has been developed for the selection, calculation and thermodynamic analysis of turbine units based on the organic Rankine cycle, which makes it possible to determine the values of the optimal parameters of the working fluid, as well as to select the working fluid with the highest exergetic efficiency for cycles on superheated steam and with intermediate overheating. The structure of the developed mathematical model for thermodynamic analysis is presented. The studies were conducted at pressures up to 20 MPa and temperatures of the working fluid in front of the turbine up to 250 °C; the temperature of the working fluid at the outlet of the condenser was 25 °C, while the maximum temperature of the working fluid at the outlet of the intermediate superheater was 250 °C. The analysis of the results showed that the use of reheating in the organic Rankine cycle – as well as in the classical (i. e. steam turbine) one – led to higher exergic efficiency of the cycle. On average, for the studied working media, the increase in exergetic efficiency at optimal parameters of the working body was 4.28 %. However, some working media significantly exceeded this result (for example, 8.14 and 6.56 % for R717 and R32, respectively) due to their thermophysical properties. The error for all low-boiling working media did not exceed 2 % of the obtained result of exergetic efficiency. Grassmann – Shargut charts were made for the studied circuits using the example of the refrigerant R245FA. Exergetic analysis demonstrated that intermediate overheating at thermodynamically optimal parameters of the working media before the high and low pressure parts of the turbine causes a decrease in exergy losses in the heat recovery boiler, a significant increase in regeneration in the heat exchanger, an increase in exergy losses in the pump and their redistribution in the turbine unit, heat exchanger and condenser.

Особенности работы водоподготовительной установки теплоутилизационного контура воздушно-аккумулирующей газотурбинной электростанции

A heat recovery system for a compressed air gas turbine power plant consists of a gas turbine unit and heat recovery boiler that requires water treatment to compensate the loss of condensate. Salt tablets are normally used for ion exchange resin regeneration on a water treatment stage. The key idea of this research is to use salt processing ponds where available to build compressed air gas turbine power plants using salt caverns. This eliminates the salt tablet cost during operation. This paper presents a comparative analysis of economic efficiency for two options such as continue applying salt tablets or start using salt brine from salt mining ponds.

Calculation of Heat Losses Through Non-Insulated Pipelines of a Waste-Heat Recovery System in a Thermal Power Plant

The paper considers the calculation of heat losses through a non-insulated pipeline section of a waste-heat recovery system in a thermal power plant. The waste-heat recovery system of a power generator includes two circuits from each unit and the network water pipelines. The first circuit of the waste-heat recovery system is the high-temperature cooling loop of the generator gas reciprocating engine. The first circuit extracts heat from the engine cooling jacket. The second circuit of the waste-heat recovery system consists of the engine exhausts heat recovery boiler, heat exchanger (heated side), network plate-type heat exchangers, and a pipeline system. In the second circuit, the heat of the first circuit and the heat of the exhausts in the heat recovery boiler is extracted. The recovery boiler pipeline with no thermal insulation is routed on the roof of the thermal power plant. The research objective was to determine the actual heat losses through the non-insulated pipeline section and to compare the obtained data with the regulatory one.