Heat Recovery Steam Generator Research Articles

Advanced Evaluation of a Biomass Externally Fired Hydrogen Production Combined Cycle

AbstractHydrogen is produced by an externally fired combined cycle and can be consumed in different ways. For the present study, both common and realistic thermodynamic and exergoeconomic analyses were applied. With the realistic method, the results are not necessarily in accordance with common analyses. The compressor pressure ratio (rp) and the gas turbine inlet temperature (TIT) are the varying parameters in common analyses. Varying rp identifies optimum energy and exergy efficiencies. With the common exergy analysis, the gasifier and the heat recovery steam generator have low exergy efficiencies, but the modified analysis assigns high exergy efficiencies to them.

Waste heat recovery of a combined regenerative gas turbine - recompression supercritical CO2 Brayton cycle driven by a hybrid solar-biomass heat source for multi-generation purpose: 4E analysis and parametric study

This study substantiates that the waste heat of a combined regenerative gas turbine cycle (GTC) and recompression supercritical CO2 Brayton cycle (SCBC) driven by a hybrid solar-biomass heat source can be effectively recovered via combining various subsystems encompassing a thermoelectric generator, an LiBr–H2O absorption refrigeration system, a heat recovery steam generator, and a proton exchange membrane electrolyzer with the cycle. The environmental and exergoeconomic performances of the system under a base case are compared between a hybrid solar-biomass mode (with direct normal irradiance (DNI) of 0.8 kW m−2) and biomass-only mode (while DNI is lower than 0.4 kW m−2). The results indicate that the employment of the solar power tower results in slight reductions in environmental impacts, while significant diminutions in thermodynamic and economic performances. For hybrid and biomass-only modes, the total energy efficiency of the system correspondingly improves by 22.48 and 29.6% points and the total exergy efficiency of the system respectively enhances by 6.18 and 7.6% points thanks to recovering the waste energy from the regenerative GTC - recompression SCBC via the proposed systems, while the utilized subsystems in the two mentioned modes respectively account for merely 5.1% and 8.1% of the system total cost rate.

Formation of arsenic−copper-containing particles and their sulfation decomposition mechanism in copper smelting flue gas

The heat recovery steam generator (HRSG) of copper smelting generates a large number of arsenic−copper- containing particles, and the in-situ separation of arsenic and copper is of importance for cutting off environmental risk and realizing resource recovery. The formation of arsenic−copper-containing particles was simulated, the method of in-situ decomposition of arsenic−copper-containing particles by pyrite was proposed, and the decomposition mechanism was confirmed. It was found that particles with high arsenic content were formed in the simulated HRSG, and copper arsenate was liable for the high arsenic content. Pyrite promoted the sulfation of copper, leading to the in-situ decomposition of copper arsenate. In this process, gaseous arsenic was released, and thus the separation of arsenic and copper was realized.

Search for a Solution to the Problem of Flow-Accelerated Corrosion in Heat-Recovery Steam Generators

Search for a Solution to the Problem of Flow-Accelerated Corrosion in Heat-Recovery Steam Generators

Compact Steam Bottoming Cycles: Minimum Weight Design Optimization and Transient Response of Once-Through Steam Generators

Compactness and weight minimization are key aspects for successful and widespread implementation of waste heat recovery steam cycles in off-shore oil and gas platforms due to the site weight and volume footprint constraints. The power plant off-shore must be designed for flexibility in its operations to provide varying power demands across multiple time scales. Reliability of the heat and power production units is crucial. Within a case study in an off-shore platform in the Norwegian Continental Shelf, this article conducts design optimization of compact and low-weight steam cycles for power production from gas turbine exhaust and transient analysis of the core of heat recovery steam generators (HRSGs) via dynamic modeling and simulation, considering once-through steam generators (OTSGs) for the HRSGs. A method for simultaneous thermodynamic and heat exchanger geometry optimization design for bottoming cycles is applied, with the main objective being weight minimization and compactness of the cycle heat exchangers. Ten different optimal minimum weight bottoming cycle designs are provided by selecting ten different manufacturable tubes. The resulting bottoming cycle designs are compared in terms of weight, OTSG core weight distribution, heat transfer area, and footprint. The resulting bottoming cycle weight varies from 48.4 to ca. 87.10 ton for designs sensible for off-shore applications, and from 95.8 to 178.9 ton when selecting outer tube diameters typical of onshore applications. Smaller outer tube diameter selection in OTSG bundles is a key driver for low-weight and compact steam cycle designs. Three different designs representing light, normal, and heavy OTSG designs are compared by dynamic trajectory and response time analysis under transient scenarios by means of dynamic modeling and simulation. More compact and lighter designs respond faster to changes in the gas turbine (GT) operation upstream the OTSG. The results in this analysis indicate the need for feedforward control. Feedback control alone is probably not a good option due to the high OTSG open loop stabilization time and large sensitivity to GT exhaust gas variations. More compact and low-weight designs based on the OTSG can reduce potential challenges in controlling and stabilizing bottoming cycles for power production.

Evaluation of cogeneration alternative systems integrating biomass gasification applied to a Brazilian sugar industry

This work presents a technical analysis of an Integrated Biomass Direct Gasification/Gas Turbine (BIG-GT) technology within a sugarcane industry to produce electricity and thermal energy (process heat) using bagasse as fuel. Four possible configurations for the implementation of this technology were considered. A sensitivity analysis was made to assess the risks and the uncertainty level for each proposed solution. The results indicated that with the BIG-GT implementation the power generation efficiency increases for all the studied configurations as compared to the conventional system (η = 14.3%). For the configurations I, II, and III the efficiency increase was 9.1%, 11.0% and 12.6%, respectively. However, to support these configurations of the system, the fuel (bagasse) consumption is increased beyond the production capacity of the mill, and the additional amount of bagasse must be acquired to other mills. On the other hand, in configuration IV it is only considered the gasification of the bagasse produced in the mill, being the additional needs of thermal energy for the industrial process supplemented through the combustion of other biomass types (sugarcane straw produced in the mill plantations) in a Heat Recovery Steam Generator. In configuration IV, the electricity generation efficiency is only 5.9% higher than the conventional cycle, this efficiency is getting without the need for an external supply of bagasse. Ultimately, the sensitivity analysis showed that the plant's energy performance with the implementation of BIG-GT technology is particularly sensitive to variations related to the gasifier's efficiency.

Development and Validation of a Dynamic Simulation Model for an Integrated Solar Combined Cycle Power Plant

The combined cycle power plants are the most recognized thermal power plants for their high efficiency, fast start-up capability, and relatively low environmental impact. Moreover, their flexible unit dispatch supports the share of renewable energy, which contributes to carbon mitigation. The operational flexibility of Integrated Solar Combined Cycle (ISCC) power plants is a crucial factor for reliable grid stability. To evaluate the limitations and capabilities of ISCC power plants and their control structures, dynamic simulation is a feasible method. In this study, a sophisticated dynamic process model of the ISCC power plant in Kuraymat, Egypt, has been developed using APROS software. The model describes the plant with a high level of detail including the solar field, the heat recovery steam generator, and the control structures. The model was implemented structurally identical to the reference plant and tuned using the operational design data. Actual measurements were used as the basis for the initialization and validation of the dynamic simulation environment. Dynamic analysis of four different days was performed, then the simulation results were presented and compared with actual measurements. The comparison showed that the course of the actual measurements could be predicted with high accuracy. The solar field influences and the system’s overall power curves are reliably simulated. Consequently, the validated model can simulate the dynamic behavior of the ISCC power plant with a high degree of accuracy, and can be considered in future planning decisions.

Process optimization and revamping of combined-cycle heat and power plants integrated with thermal desalination processes

Optimal revamping, sizing, and operation of an existing gas-turbine combined-cycle dual-purpose power/desalination plant – simultaneous electricity and freshwater generation – which operates with a heat recovery steam generation with one-pressure level (1P-HRSG) and a multi-stage flash desalination process, is addressed. The sizes and configurations of the gas turbine and desalination unit are kept the same as in the existing plant through the study. However, the 1P-HRSG is conveniently extended to two- or three-pressure levels with different exchanger arrangements, including steam reheating. To this end, a superstructure-based representation of the HRSG simultaneously embedding several candidate structures was proposed and a mixed-integer nonlinear programming model was derived from it.One revamping case consisted in maximizing the ratio between the freshwater production rate and the heat transfer area of HRSG, keeping unchanged the electricity generation rate (around 73 MW). It was found that the inclusion of a 3P-HRSG resulted in an increase of 13.782 kg⋅s−1 in the freshwater production, requiring 22753 m2 of heat transfer area less in the HRSG. Another revamping case consisted in maximizing the profit, contemplating the possibility to sell extra amounts of electricity and freshwater. Sale prices, for which producing extra electricity and freshwater is beneficial, were determined.

On The Thermodynamics of Dual Purpose Power Desalting Plants with Gas Turbine.(Dept.M)

Recent advances in gas turbine cycles and combined gas/steam turbine cycles are presented. First and second law analysis of gas turbine cycles is presented and shows that substantial available energy (up to 30% of fuel availability) is carried out by gas turbine exhaust gases. This available energy can be utilized for further heat to work conversion or for direct process heating. Heat recoverd from gas turbine exhaust gases in heat recovery steam generator (HRSG) can generate relatively high pressure steam to be supplied to Rankine steam power cycle to form gas/steam power cycle of high efficiency (40-45%). Steam can be generated at low pressure in the HRSG for direct supply to the brine heater of a multistage flash (MSF) desalting system. Possible combination of simple gas turbine cycle or combined gas/steam cycle with reverse osmosis or MSF sea water desalting systems are presented and evaluated. The evaluation indicates that most of these combination are more superior than combination with steam power plants from energy view points.

Heat Recovery Steam Generators of Binary Combined-Cycle Units

Heat Recovery Steam Generators of Binary Combined-Cycle Units

An Efficient Energy Utilization of Biomass Energy-Based System for Renewable Hydrogen Production and Storage

Abstract The increasing environmental limits and carbon emissions taxes are substantial to develop the efficient systems for offering an effective energy utilization. This study proposed a new biomass-based gasification-assisted configuration for the renewable hydrogen production system offering efficient energy utilization. A multi-effect desalination system is employed for water desalination which is converted to steam and fed to the entrained flow gasifier. The integrated heat recovery steam generator gains the additional heat from the syngas to generate steam using fresh water from the desalination unit. The produced hydrogen is supplied to the multistage compression unit that stores hydrogen at high pressure. Industrial aspen plus software V9 version is employed for the simulation under the RK-SOAVE property method. The production of hydrogen before the water gas shift reactor is 129.5 mol/s and after the water gas shift reactor is found to be 171 mol/s. The thermodynamic performance of the biomass energy-assisted system is determined through overall energetic and exergetic efficiencies that are revealed to be 40.86% and 38.63%. Numerous sensitivity studies are performed to explore the performance of the designed system and presented and discussed.

Enhanced thermodynamic and economic investigation of using heat recovery steam generators for solar thermal power plants

This study investigates the use of heat recovery steam generators (HRSGs) connected to three types of concentrated solar power (CSP) technologies for solar thermal power plants for the city of Faro-Poli located in northern Cameroon. The HRSGs are designed for the solar thermal power plants using solar tower (ST) technology as HRSG-1 and using parabolic trough collector (PTC) and linear Fresnel reflector (LFR) technologies as HRSG-2. HRSG-1 operates under temperatures between 56.4 and 314.9 °C, whereas HRSG-2 (PTC) and HRSG-2 (LFR) work under temperatures between 57.9 and 264 °C. The exergoeconomic analysis reveals that costs per exergy unit of the solar field system vary from 2.31 to 5.32 $/GJ and that relative cost differences and exergoeconomic factors of HRSG-1 (ST), HRSG-2 (PTC), and HRSG-2 (LFR) are 0.086 and 90.0%, 0.063 and 85.2%, and 0.112 and 72.0%, respectively. The results also show that costs per exergy unit of the HRSGs connected to these three CSP technologies are between 2.41 and 8.41 $/GJ. The avoidable-endogenous exergy destruction values are 158.5, 498.8, and 570.4 kW for HRSG-1 (ST), HRSG-2 (PTC), and HRSG-2 (LFR), respectively. Further, it is seen that HRSG-1 owns the lowest levelized cost rate of product with a value of 0.36 $/h, while the other two HRSG-2 technologies have a value of 1.08 $/h. Finally, the sensitivity analysis shows the cost reduction potential of the HRSGs to make them economically viable. It is concluded that the HRSG-1 (ST) is the most efficient technology considering its impact on the overall exergy efficiency, the levelized cost rate of product, and the cost per exergy unit.

Estimating the Steam Quality in Power-Generating Boilers from Electrical Conductivity and pH Measurements

The quality of steam produced by boilers is strictly standardized and must be maintained whatever the quality of makeup water and whatever the composition of the boiler unit’s thermal cycle equipment. Under the conditions of constantly improved instruments for chemical monitoring, it becomes possible to develop measurement systems using which the main standardized and diagnostic steam quality indicators can be monitored by measuring the electric conductivity and pH of cooled samples. Unlike boilers operating at a pressure of 13.8 MPa and higher, steam boilers for steam pressures equal to 9.8 and 3.9 MPa—and also industrial heat recovery steam generators—operate with steam that has a higher content of salts and carbon dioxide; in addition, it contains ammonia, which enters into steam from boiler water. Steam quality is often estimated using the two-quadrant nomographic chart of Mostofin, who proposed it more than 50 years ago. In using certain computation algorithms, it is possible to calculate the standardized and diagnostic steam quality indicators, such as concentrations of sodium, chlorides, ammonia, carbon dioxide, and salt content. The article presents an algorithm for estimating the concentrations of the above-mentioned impurities for cooled live steam samples of power-generating boilers operating at pressures below 10.0 MPa, and boilers for superhigh and supercritical pressures, and industrial heat recovery steam generators, including the combined-cycle power plant units. Examples of using the calculation procedure for analyzing the steam quality in industrial boilers are given.

배열회수보일러 복수예열기 부식 파손 분석

In this work, we have performed a corrosion failure analysis of a leaking tube connected to an upper header of a condensate pre-heater in a heat recovery steam generator. It was revealed that the leakage position in the tube was the location where the materials were easily vulnerable due to tensile residual stresses induced by the material manufacturing process and welding process. In addition to an imbalance in the module induced by temperature difference during operation of the pre-heater, the weight of the modules and thermal fatigue provoked a type of stress of tensile-tensile fatigue on the tube. Thus, the leakage position of the pre-heater was exposed to the tensile stress on the inner surface of the tube facing the gas, which rendered the unstable oxide layer susceptible to corrosion and the formation of pits on the water side. The cracks propagated along with the degraded microstructure in a transgranular cracking mode under fatigue loading and finally resulted in water leakage.

Heat recovery steam generator (HRSG) three-element drum level control utilizing Fractional order PID and fuzzy controllers

Shrink and swell is a phenomenon that causes transient variability in water level once boiler load variation occurs. The leading cause of the swell effect is the steam demand changes and the actual arrangement of steam generating tubes in the boiler. Steam bubbles beneath HRSG drum water make the level control very difficult, particularly with significant disturbances in the input heat to HRSG. Plant shutdown may occur in some situations, and combined cycle plant efficiency is diminished. The recently applied control methods in industry are single-element and three-element control with PID controllers, but these methods are not well suited for substantial load changes. The main aim of this paper is to investigate the shrink and swell phenomenon inside HRSG power plants. In addition to the existing PID loops, two different standalone controllers, namely, the FOPID controller and fuzzy controller, are implemented with the HRSG model. Besides, Artificial Bee Colony (ABC) algorithm is used to tune FOPID efficiently. Based on overshoot, rise time, ISE, IAE, ITAE as performance measures, the comparison has been held between the three controllers. Simulations show that how the ABC optimization algorithm is efficient with PID, FOPID. It turns out that the proposed method is capable of improving system responses compared to the conventional optimal controller.

Regional management of flare gas recovery based on water-energy-environment nexus considering the reliability of the downstream installations

Water-energy-environment nexus was employed in a sample city for flare gas recovery while the reliability of downstream installation is taken into account. First, considering the average characteristics of a house, water and energy demands were estimated. The residential section's water and energy demands were then supplied using flare gas recovery from an oil field near the city. The study was conducted in two scenarios based on meeting the total annual electricity demand and the residential sector's total annual natural gas demand. A hybrid system including a natural-gas liquid refinery, a gas turbine power plant, a heat recovery steam generator, and multi-effect desalination was proposed as downstream installations. By system reliability's consideration using the Markov technique, a novel integrated model was developed to assess different proposed scenarios. In both scenarios, the water and energy shortages could be provided by the network, and the surplus can be sold to the network. It was shown that considering the reliability of technology significantly affects the final configuration of flare gas recovery technology. It was shown that consideration of employed installations' reliability affects the proposed flare gas recovery technologies' features. Accordingly, the first scenario with a capital cost of 236.94 M$ and a product sales income of 93.31 M$, with 1.3 years of return payback period, was selected as the best solution.

Energy-Exergy Analysis of Solarized Triple Combined Cycle Having Intercooling, Reheating and Waste Heat Utilization

Heliostat-based solar thermal power system consisting of a combination of the Brayton cycle, Rankine cycle, and organic Rankine cycle is a potential option for harnessing solar energy for power generation. Among different options for improving the performance of solarized triple combined cycle the option of introducing intercooling and reheating in the gas turbine cycle and utilizing the waste heat for augmenting the power output needs investigation. Present study considers a solarized triple combined cycle with intercooling and reheating in gas turbines while using the heat rejected in intercooling in heat recovery vapour generator and heat recovery steam generator separately in two different arrangements. A comparison of two distinct cycle arrangements has been carried out based on Ist law and IInd law of thermodynamics with the help of thermodynamic parameters. Results show that triple combined cycle having intercooling heat used in heat recovery vapour generator offers maximum energy efficiency of 63.54% at 8 CPR & 300K ambient temperature and maximum exergetic efficiency of 38.37% at 14 CPR & 300 K. While the use of intercooling heat in heat recovery steam generator offers maximum energy and exergetic efficiency of 64.15% and 39.72% respectively at 16 CPR & 300 K ambient temperature.

A comprehensive approach for the multi-objective optimization of Heat Recovery Steam Generators to maximize cost-effectiveness and output power

Environmental problems have offered new challenges to the energy production sector, starting from the need of increasing the efficiency of thermodynamic systems to preserve fuel consumption. Accordingly, multi-energy generation systems are among the most efficient generation systems, and Heat Recovery Steam Generators (HRSGs) represent key components of such systems. In this regard, this paper shows a comprehensive approach to optimize a HRSG by using a multi-objective Genetic Algorithm (GA). The aim is to highlight how to determine the optimal values of geometrical and thermodynamic design variables according to two objective functions: the global costs to be minimized and the steam turbine output power to be maximized. Starting from a reference HRSG design, thermodynamic modeling and simulations as well as the optimization procedure are performed in MATLAB®. A validation is carried out to show the accuracy of the modeling approach. Latin Hypercube Sampling is applied to create a uniform sample to select the design variables based on a global sensitivity analysis, producing a significant reduction of computational efforts. Then, the GA optimization is performed to achieve the Pareto front, collecting the best trade-off design solutions. Economic savings up to 20% are achieved limiting the HRSG size.

Advanced Exergy and Exergoeconomic Analysis of a Gas Power System with Steam Injection and Air Cooling with a Compression Refrigeration Machine

Gas turbine power plants have been widely studied, and as a result the negative effects on their output power and thermal efficiency have been known when operating in atmospheric conditions exceeding ISO conditions. For this reason, different technologies and methodologies have been implemented, aiming to increase the output power and improve the thermal efficiency. Unfortunately, the lack of operational parameters for this system limited its characterization and implementation of strategies to improve its performance. Advanced exergetic and exergoeconomic analyses have been applied to improve energy and economic performance in steam injection gas turbine (STIG) cycle power plants with air cooling with a compression refrigeration machine. Results shows that the main sources of irreversibilities and higher costs are in the Combustion Chamber (CC), Heat Recovery Steam Generator (HRSG) and Gas Turbine (GT). From these components, the components of the HRSG and GT have the greatest potential for improvement, and this can be achieved by improving the overall configuration of the system, due to the fact that the destruction of exogenous exergy is in more significant measure avoidable. While the higher costs of investment can be reduced in the Combustion Chamber and Gas Turbine.

Modeling and multi-objective optimization of integrated MED–TVC desalination system and gas power plant for waste heat harvesting

A multi-effect desalination–thermal vapor compression (MED–TVC) system consuming the waste heat from the gas power plant of the Sarcheshmeh Copper Complex is designed and optimized by a new approach that integrates two environments: a MATLAB simulator and macros for economic analysis. A heat recovery steam generator (HRSG) is used to supply the required heat for steam generation while harvesting the waste heat. The HRSG and MED–TVC systems are simulated using MATLAB, and their economic analysis is conducted using DEEP software. The gain output ratio (GOR) and the total annual cost of desalination are considered as the objective functions in a multi-objective optimization to achieve the highest GOR and the lowest total annual cost simultaneously. The multi-objective optimization is performed using nondominated sorting genetic algorithm-II (NSGA II). It is found that the heating steam temperature is more affected by the GOR than the other decision variables.