Investigations on Dynamic Behaviour of Heat Recovery Steam Generators Carried Out With a Commercial Software Program

2007 ◽  
Author(s):  
Gottfried Brandstetter ◽  
Christian Daublebsky
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Waste Heat ◽  
Important Process ◽  
Steel Mill ◽  
Steam Generators ◽  
Commercial Software ◽  
Software Program ◽  
Firing System

Heat recovery steam generators (HRSGs) downstream of gas turbines are often used in combination with process steam applications. A HRSG trip is more severe in applications with highly important process steam than in applications producing only electricity. HRSGs in important process steam applications can be equipped with a supplementary and fresh air firing system having the capacity of replacing at least the total waste heat coming from the gas turbine. A fresh air firing system provides the capability of keeping the HRSG in operation without the gas turbine running. If the HRSG is required to stay in operation even after a gas turbine trip, a change over from waste heat firing to fresh air firing has to follow immediately. The gas turbine speed rundown after a trip occurs very rapidly, so the change over procedure has to be carried out within a few seconds to avoid a HRSG shut down. Enormous gradients of heat input and steam mass flow extracted from the HRSG occur in such cases. This will cause the HRSG parameters to deviate considerably from the steady state, thus conventional HRSG calculations cannot be used in such cases. The thermal inertia of the HRSG needs to be considered, which requires the use of special software programs. A commercial boiler software program with a dynamic calculation module for unsteady calculations was utilized and a comparison with data gathered from the operation of the HRSG was performed. The boiler performance parameters during change over procedures were investigated in detail using extensive measurements at an Austrian steel mill (VOESTALPINE). The parameters of this investigation were compared with calculation results gained from a commercial software program for validation purposes. This comparison will enable predictions to be made for future projects with sufficient accuracy, which will allow the risk to be reduced when offering guarantees in this regard.

How to Change Over Heat Recovery Steam Generators After Gas Turbine Trip

2006 ◽  
Author(s):  
Gottfried Brandstetter ◽  
Wolfgang Oberleitner ◽  
Michael Pichler
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Oxygen Supply ◽  
Waste Heat ◽  
Exhaust System ◽  
Steel Mill ◽  
Steam Generators ◽  
Time Period ◽  
Firing System

Heat recovery steam generators downstream of gas turbines are often used in combination with process steam applications. Because of the high importance of the required process steam, a boiler trip is more severe than in usual applications, where only electricity is produced. In most cases these boilers are equipped with a supplementary and fresh air firing system having the capacity of replacing the whole waste heat coming from the gas turbine or even more. A fresh air firing system offers the possibility to keep the boiler in operation without the gas turbine running. If the boiler has to stay in operation even after a gas turbine trip a change over from waste heat firing to fresh air firing has to follow immediately. Due to the very sharp breakdown of the gas turbine speed after trip, the change over procedure has to be carried out within a few seconds to avoid a boiler shut down. The problems are — on the one hand — not to have to switch off the supplementary firing, on the other hand not to exceed the backpressure of the gas turbine because of too fast closing of dampers necessary for fresh air firing. The first would cause a necessary purging with a certain time period without firing, the second would lead to damages of the gas turbine exhaust system. Backpressure and oxygen supply have to be managed carefully to provide a smooth and save change over. In addition it has to be considered, that the first time period after gas turbine trip, the oxygen supply of the boiler’s firing has to be ensured by the running out gas turbine. Special investigations allow to predict the amount of exhaust gas mass flow after gas turbine trip by using the speed behavior of a reference gas turbine trip. At an Austrian steel mill (VOESTALPINE) these procedures were investigated in detail, and a lot of measurements were done. Based on this the existing change over procedure was optimized and the possibility of a quick change over procedure was realized.

scholarly journals General Design Considerations for Gas Turbine Waste Heat Steam Generators

1968 ◽  
Author(s):  
W. V. Hambleton
Keyword(s):  
Gas Turbine ◽  
Heat Recovery ◽  
Waste Heat ◽  
Steam Generation ◽  
Steam Generators ◽  
Design Considerations ◽  
Exhaust Heat ◽  
Gas Turbine Exhaust ◽  
Exhaust Heat Recovery ◽  
Turbine Exhaust

This paper represents a study of the overall problems encountered in large gas turbine exhaust heat recovery systems. A number of specific installations are described, including systems recovering heat in other than the conventional form of steam generation.

scholarly journals Waste Heat Recovery for Offshore Applications

2012 ◽  
Author(s):  
Leonardo Pierobon ◽  
Rambabu Kandepu ◽  
Fredrik Haglind
Keyword(s):  
Gas Turbine ◽  
Thermal Energy ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Oil And Gas ◽  
Waste Heat ◽  
Offshore Platforms ◽  
Organic Rankine Cycles ◽  
Heat Loads

With increasing incentives for reducing the CO2 emissions offshore, optimization of energy usage on offshore platforms has become a focus area. Most of offshore oil and gas platforms use gas turbines to support the electrical demand on the platform. It is common to operate a gas turbine mostly under part-load conditions most of the time in order to accommodate any short term peak loads. Gas turbines with flexibility with respect to fuel type, resulting in low turbine inlet and exhaust gas temperatures, are often employed. The typical gas turbine efficiency for an offshore application might vary in the range 20–30%. There are several technologies available for onshore gas turbines (and low/medium heat sources) to convert the waste heat into electricity. For offshore applications it is not economical and practical to have a steam bottoming cycle to increase the efficiency of electricity production, due to low gas turbine outlet temperature, space and weight restrictions and the need for make-up water. A more promising option for use offshore is organic Rankine cycles (ORC). Moreover, several oil and gas platforms are equipped with waste heat recovery units to recover a part of the thermal energy in the gas turbine off-gas using heat exchangers, and the recovered thermal energy acts as heat source for some of the heat loads on the platform. The amount of the recovered thermal energy depends on the heat loads and thus the full potential of waste heat recovery units may not be utilized. In present paper, a review of the technologies available for waste heat recovery offshore is made. Further, the challenges of implementing these technologies on offshore platforms are discussed from a practical point of view. Performance estimations are made for a number of combined cycles consisting of a gas turbine typically used offshore and organic Rankine cycles employing different working fluids; an optimal media is then suggested based on efficiency, weight and space considerations. The paper concludes with suggestions for further research within the field of waste heat recovery for offshore applications.

Performance Assessment of Steam Injection Gas Turbine With Inlet Air Cooling

1997 ◽  
Author(s):  
Carlo M. Bartolini ◽  
Danilo Salvi
Keyword(s):  
Ambient Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Power Plants ◽  
Waste Heat ◽  
Cooling System ◽  
Steam Injection ◽  
Maximum Efficiency ◽  
Air Cooling

The steam generated through the use of waste heat recovered from a steam injection gas turbine generally exceeds the maximum mass of steam which can be injected into steam injection gas turbine. The ratio between the steam and air flowing into the engine is not more than 10–15%, as an increase in the pressure ratio can cause the compressor to stall. Naturally, the surplus steam can be utilized for a variety of alternative applications. During the warmer months, the ambient temperature increases and results in reduced thermal efficiency and electrical capacity. An inlet air cooling system for the compressor on a steam injection gas turbine would increase the rating and efficiency of power plants which use this type of equipment. In order to improve the performance of steam injection gas turbines, the authors investigated the option of cooling the intake air to the compressor by harnessing the thermal energy not used to produce the maximum quantity of steam that can be injected into the engine. This alternative use of waste energy makes it possible to reach maximum efficiency in terms of waste recovery. This study examined absorption refrigeration technology, which is one of the various systems adopted to increase efficiency and power rating. The system itself consists of a steam injection gas turbine and a heat recovery and absorption unit, while a computer model was utilized to evaluate the off design performance of the system. The input data required for the model were the following: an operating point, the turbine and compressor curves, the heat recovery and chiller specifications. The performance of an Allison 501 KH steam injection gas plant was analyzed by taking into consideration representative ambient temperature and humidity ranges, the optimal location of the chiller in light of all the factors involved, and which of three possible air cooling systems was the most economically suitable. In order to verify the technical feasibility of the hypothetical model, an economic study was performed on the costs for upgrading the existing steam injection gas cogeneration unit. The results indicate that the estimated pay back period for the project would be four years. In light of these findings, there are clear technical advantages to using gas turbine cogeneration with absorption air cooling in terms of investment.

Flow Distribution Characteristics and Control in Marine Gas Turbine Diffusers

1984 ◽  
Vol 106 (3) ◽  
pp. 654-660
Author(s):  
M. K. Ellingsworth ◽  
Ho-Tien Shu ◽  
S. C. Kuo
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Flow Distribution ◽  
Distribution Characteristics ◽  
Nonuniform Flow ◽  
Technical Problems ◽  
And Control

The object of this study was to investigate flow distribution characteristics and control in the marine gas turbine diffusers most suitable for waste heat recovery systems. The major technical problems associated with nonuniform flow distributions in heat-exchanger or flow-equipment systems were reviewed. Various means to alleviate or minimize these undesirable problems were evaluated. Four sets of candidate flow-distribution data were selected from the measured exhaust velocities of typical marine gas turbines for input to the present study. A two-dimensional turbulent flow model for diffusers was developed and computerized, and five diffuser geometries suitable for marine gas turbine waste-heat recovery applications were investigated, based on the actual inlet velocity data. The exit flow distribution characteristics (velocity, mass-flux, pressure recovery, and temperature) and diffuser performance with and without flow-distribution controls were analyzed using the computer programs developed. It was found that nonuniform flow distribution in the gas turbine exhaust can reduce diffuser efficiency to half of that attainable with uniform flow, and that the diffuser exhaust velocities will be more uniform by using guide vanes and/or flow injection than merely using nonsymmetric diffusion angles. The diffuser efficiency can be improved 20 to 36 percentage points by using these contort means.

scholarly journals The Design and Economics of On-Site Generation With Aircraft-Type Gas Turbines for a Chemical Complex

1967 ◽  
Author(s):  
A. B. Crouchley ◽  
C. E. Carroll’
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Steam Generation ◽  
Chemical Complex ◽  
Optimum Approach ◽  
Aircraft Type ◽  
Technical Considerations

This paper discusses the economic and technical considerations involved in the decision of a large chemical complex to install on-site power generation; why the gas turbine with waste-heat recovery for process steam generation was determined to be the optimum approach; and the reasons for selecting the aircraft-type gas turbine for this particular application. A brief description of plant components and operation is also included.

Application of the Shell DeNOx System on Gas Turbine-Heat Recovery Steam Generators

1997 ◽  
Author(s):  
Gregory P. Croce ◽  
Wessef Yistra ◽  
Richard Kinsfather ◽  
David Hamilton
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Catalytic Reduction ◽  
Operating Experience ◽  
Steam Generators ◽  
Temperature Capability ◽  
Temperature Window ◽  
Scr System ◽  
Conventional Medium

The Shell DeNOx System (SDS) is an innovative selective catalytic reduction (SCR) system in which NOx emission reduction efficiencies greater than 90% can be achieved from fluegas streams at temperatures as low as 163 °C (325 °F). The low temperature capability allows the SDS to be positioned at the tail-end of a furnace convection section or gas turbine HRSG. This feature permits the installation of SDS without the extensive retrofit costs associated with the implementation of conventional (medium or high) temperature SCRs which require a 288–385 °C (550–725 °F) or 427–593 °C (800–1100 °F) temperature window, respectively. This paper will discuss the application and operating experience of the SDS on gas turbines heat recovery steam generators (GT-HRSG).

scholarly journals One of the World’s Biggest Desalination Plants in Dubai: Jebel Ali Gas Turbine and MSF Desalination Station “G”

1994 ◽  
Author(s):  
Paul Gilli ◽  
Gerhard Stroiβnig ◽  
Rudolf Povoden
Keyword(s):  
Gas Turbine ◽  
Oil And Gas ◽  
Waste Heat ◽  
Saturated Steam ◽  
Heat Recovery Boiler ◽  
Steam Generators ◽  
Electric Capacity ◽  
Desalination Plants ◽  
The City ◽  
Firing System

Near the city of Dubai a gas turbine and desalination station is presently being commissioned and has already partly been taken over by the client. This project has been carried out within 34 months from the award of the order to the acceptance by the client by an international consortium. Upon its completion the plant will produce 60 million gallons of drinking water per day and will have an electric capacity of 457 MW. The paper presents the technical concept of steam generators of relatively big capacity and very low steam pressures for the production of saturated steam for two designs, i.e. an oil and gas fired self-supporting steam generator and a waste heat recovery boiler behind a gas turbine including a very powerful supplementary firing system.

Part-Load Operation of Combined Cycle Plants With and Without Supplementary Firing

1995 ◽  
Vol 117 (3) ◽  
pp. 475-483 ◽  
Author(s):  
P. J. Dechamps ◽  
N. Pirard ◽  
Ph. Mathieu
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Power Plants ◽  
Combined Cycle ◽  
Steam Generators ◽  
Part Load ◽  
Inlet Guide Vanes ◽  
Steam Plant

The design point performance of combined cycle power plants has been steadily increasing, because of improvements both in the gas turbine technology and in the heat recovery technology, with multiple pressure heat recovery steam generators. The concern remains, however, that combined cycle power plants, like all installations based on gas turbines, have a rapid performance degradation when the load is reduced. In particular, it is well known that the efficiency degradation of a combined cycle is more rapid than that of a classical steam plant. This paper describes a methodology that can be used to evaluate the part-load performances of combined cycle units. Some examples are presented and discussed, covering multiple pressure arrangements, incorporating supplemental firing and possibly reheat. Some emphasis is put on the additional flexibility offered by the use of supplemental firing, in conjunction with schemes comprising more than one gas turbine per steam turbine. The influence of the gas turbine controls, like the use of variable inlet guide vanes in the compressor control, is also discussed.

scholarly journals Design Optimization of a Gas Turbine Based Cogeneration Plant With Steam Supply to Process Plant

1982 ◽  
Author(s):  
L. F. Giannuzzi ◽  
O. E. Horn ◽  
N. Nakhamkin
Keyword(s):  
Gas Turbine ◽  
Power Supply ◽  
Gas Turbines ◽  
Heat Recovery ◽  
System Optimization ◽  
Cogeneration Plant ◽  
Steam Generators ◽  
Desalination Plant ◽  
Process Plant ◽  
Desalination Plants

This paper presents the results of Gibbs & Hill, Inc.’s studies, engineering, and implementation of a cogeneration plant consisting of gas turbines and heat recovery steam generators. The plant is designed for fluctuating power supply and stable steam supply requirements to a multistage flash (MSF) type Desalination Plant. This paper emphasizes the advantages of an Integrated Power/Desalination Plant System Optimization as against separate optimization of power and desalination plants.

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