Nuclear Gas Turbines: Small-Scale Inherently Safe, Well-Proven Nuclear Power

Author(s):  
H. van Dam ◽  
T. H. J. J. van der Hagen

The paper discusses uranium as a new fuel for gas turbines used as energy conversion installations for the markets of: stand-alone heat production, combined heat and power generation, stand-alone electricity production and as prime mover on board ships. This development is a logical step in a historical trend in energy conversion. The paper discusses the availability of the fuel, uranium and the construction of the fuel which makes this combination of gas turbine and uranium suitable for the non-utility markets.

Author(s):  
Gulian A. K. Crommelin ◽  
Walter F. Crommelin

Gas turbines in combination with a nuclear heat source have been subject for study for some years. This paper is a logical follow up on previous papers regarding small scale nuclear power generation using gas turbines with a well-proven, inherently safe nuclear heat source. In the Netherlands the NEREUS project has been working on this concept since 1993. The acronym NEREUS describes very well the goals of this project. (Ref 1, 2, 3, 4, 5). NEREUS stands for: a Natural safe, Efficient, Reactor, Easy to operate, Ultimately simple and Small. Current studies focus on the gas turbine part of the installation. After three years of studying the possibilities of the closed cycle helium gas turbine, the NEREUS project returned in 2000 to its original thought of using an existing open-cycle gas turbine or components of such an engine, as energy conversion unit. The paper starts with an introduction on why nuclear power should get more attention, basically explaining “the reasons why” of the NEREUS project. Secondly the paper gives an overview of the main characteristics of the nuclear heat source. Thirdly the paper will discuss the current study to determine the specifications of an open-cycle gas turbine for the NEREUS installation. Attention is given to the way such an open-cycle gas turbine can be controlled. The nuclear heat source is controlled by the laws of physics and it is not recommended to intervene under any circumstances with this very important safety feature.


2004 ◽  
Vol 126 (2) ◽  
pp. 329-333 ◽  
Author(s):  
G. A. K. Crommelin

Over the last few years a number of papers have discussed the progress on studies and thoughts on small-scale nuclear power, especially nuclear power conversion systems aiming at the nonutility markets, such as the stand-alone heat generation, combined heat and power production, stand-alone electricity conversion, and ship propulsion. The design of these installations must fully comply with the philosophies as are common in these markets, where the expression “the engine is a means to an end” applies. So design to cost, design to be operated by non professional energy producers, to be managed by a pool-management system, maintained, repaired and overhauled by replacement, etc. The paper will discuss such a design. So far all papers mentioned have discussed the gas turbine directly coupled to the heat source. However, the helium turbine is considered quite a challenge for the gas turbine industry, so alternatives had to be found. At the moment the possibilities of gas turbines with an indirect heat source (to burn refuse, wood, refinery waste, etc.) are getting much more attention. The paper therefore will discuss how an inherently safe, well proven, nuclear heat source can be coupled by an intermediate heat exchanger to a recuperative, existing but adapted gas turbine.


Author(s):  
Samarth Jain ◽  
Soumya Roy ◽  
Abhishek Aggarwal ◽  
Dhruv Gupta ◽  
Vasu Kumar ◽  
...  

The art and science of gas turbine has traditionally seen a gradual and continuous change over the past few decades. Gas turbines are classified into impulse and reaction types and further into turbojet, turbofan, turboprop, after burning turbojet and micro gas turbine. These turbines find applications in airplanes, large scale industries etc. but these are less suitable for the small scale power generation units due to several factors. Micro gas turbines are set to play a significant role particularly in small-scale power generation using combined heat and power generation among all these types of turbines as the future of power generation lies in decentralised and distributed power generation systems. In the light of making use of the high temperature exhaust of a gas turbine, combined heat and power generation systems are being used to increase the power output and overall efficiency. Micro gas turbines are essentially single-stage, single-shaft and low pressure gas turbines whose capacity ranges from 30–150 KW. In comparison to the conventional turbines, micro gas turbines are compact and have low lubricating oil consumption leading to a simpler lube and sump oil system and because they have fewer rotating parts, this leads to lesser balancing problems. The analysis of micro gas turbines has shown that they are capable of meeting current emission standards of NOx and other pollutants. Even though the installation costs of micro gas turbines are high due to the complexity in adjusting to electrical grid frequency, still these distributed energy systems may prove to be more attractive in a competitive market to those seeking increased reliability as they empower these entities with the capacity of self-generation. The following text reviews the developments in the micro gas turbines with a special focus on the efficiency of its components such as the recuperator, the combustion chamber design and also explores the future prospects of the technology in terms of viability of its application in the automobile sector.


Author(s):  
Matti Malkamäki ◽  
Ahti Jaatinen-Värri ◽  
Antti Uusitalo ◽  
Aki Grönman ◽  
Juha Honkatukia ◽  
...  

Decentralized electricity and heat production is a rising trend in small-scale industry. There is a tendency towards more distributed power generation. The decentralized power generation is also pushed forward by the policymakers. Reciprocating engines and gas turbines have an essential role in the global decentralized energy markets and improvements in their electrical efficiency have a substantial impact from the environmental and economic viewpoints. This paper introduces an intercooled and recuperated three stage, three-shaft gas turbine concept in 850 kW electric output range. The gas turbine is optimized for a realistic combination of the turbomachinery efficiencies, the turbine inlet temperature, the compressor specific speeds, the recuperation rate and the pressure ratio. The new gas turbine design is a natural development of the earlier two-spool gas turbine construction and it competes with the efficiencies achieved both with similar size reciprocating engines and large industrial gas turbines used in heat and power generation all over the world and manufactured in large production series. This paper presents a small-scale gas turbine process, which has a simulated electrical efficiency of 48% as well as thermal efficiency of 51% and can compete with reciprocating engines in terms of electrical efficiency at nominal and partial load conditions.


Author(s):  
James DiCampli

Combined heat and power (CHP) is an application that utilizes the exhaust heat generated from a gas turbine and converts it into a useful energy source for heating & cooling, or additional electric generation in combined cycle configurations. Compared to simple-cycle plants with no heat recovery, CHP plants emit fewer greenhouse gasses and other emissions, while generating significantly more useful energy per unit of fuel consumed. Clean plants are easier to permit, build and operate. Because of these advantages, projections show CHP capacity is expected to double and account for 24% of global electricity production by 2030. An aeroderivative power plant has distinct advantages to meet CHP needs. These include high thermal efficiency, low cost, easy installation, proven reliability, compact design for urban areas, simple operation and maintenance, fuel flexibility, and full power generation in a very short time period. There has been extensive discussion and analyses on modifying purge requirements on cycling units for faster dispatch. The National Fire Protection Association (NFPA) has required an air purge of downstream systems prior to startup to preclude potentially flammable or explosive conditions. The auto ignition temperature of natural gas fuel is around 800°F. Experience has shown that if the exhaust duct contains sufficient concentrations of captured gas fuel, and is not purged, it can ignite immediately during light off causing extensive damage to downstream equipment. The NFPA Boiler and Combustion Systems Hazards Code Committee have developed new procedures to safely provide for a fast-start capability. The change in the code was issued in the 2011 Edition of NFPA 85 and titled the Combustion Turbine Purge Credit. For a cycling plant and hot start conditions, implementation of purge credit can reduce normal start-to-load by 15–30 minutes. Part of the time saving is the reduction of the purge time itself, and the rest is faster ramp rates due to a higher initial temperature and pressure in the heat recovery steam generator (HRSG). This paper details the technical analysis and implementation of the NFPA purge credit recommendations on GE Power and Water aeroderivative gas turbines. This includes the hardware changes, triple block and double vent valve system (or drain for liquid fuels), and software changes that include monitoring and alarms managed by the control system.


Author(s):  
Gulian A. K. Crommelin ◽  
Walter F. Crommelin

This study is about a much discussed and recommended application of a nuclear gas turbine and was undertaken at the request of many visitors to the Nuclear Gas Turbine stand at the ASME IGTI 2002 in Amsterdam. Apparently, the specifications of the NEREUS plant led their thoughts to small-scale energy production combined with fresh water production. This thought fits well into the basic idea that: Energy equals Electricity, Heat and Fresh Water. The NEREUS project is a non-profit organisation seeking to expand the use of Small Scale Nuclear Power Generation. This paper discusses the possibilities to produce fresh water with a NEREUS inherently safe nuclear power plant. The acronym NEREUS describes very well the goals of this project and stands for: A Natural safe, Efficient, Reactor, Easy to operate, Ultimately simple and Small. Fresh water can be produced using any fossil fuelled energy conversion unit, but this study works out how the advantages of a gas turbine in combination with an inherently safe and well-proven nuclear heat source combines the advantages of a gas turbine with the logistic advantages of nuclear power. The paper starts with an introduction on why the energy conversion branch should pay more attention to fresh water production. Secondly the paper gives an overview of the main characteristics of the nuclear heat source. Thirdly the paper briefly explains the most common methods used for fresh water produced. Finally the paper will discuss the conclusion of this study, which was: The ENERGY demand of 27648 people can be fully and affordably satisfied in both quantity and quality, with a well-proven, inherently safe, self controlling nuclear pebble-bed 20 MWth reactor. Such a reactor is suitable for unmanned operation with a three year refuelling and maintenance cycle, and with the dimensions of 10 × 10 × 10 meters.


Author(s):  
Juha Kaikko ◽  
Jari L. H. Backman ◽  
Lasse Koskelainen ◽  
Jaakko Larjola

Externally-fired microturbines (EFMT) yield promising performance in small-scale utilization of biofuels. As in larger gas turbines, the part-load performance of the EFMT is very sensitive to the selected power control method, and in general subject to severe degradation at part load. The control parameters typically include the maximum combustion gas temperature or turbine inlet temperature and the speed of the shaft. At the design point, power generation efficiency can be increased by allowing a fraction of air to bypass the burner and the combustion gas – air heat exchanger. At the same time the heat exchanger size is increased. Therefore, the by-pass flow affects the optimal sizing of the EFMT as well. In this paper, the effect of by-pass flow on the part-load performance of a single-shaft EFMT in combined heat and power generation is analyzed. In the application, the microturbine is operated by the heat demand. The control methods incorporate the use of the maximum combustion gas temperature, the speed of the shaft, and the amount of by-pass air. The focus of the study is to determine the economically optimal control scheme for the engine. The economy model uses the profit flow from the EFMT as a criterion. The results show that the inclusion of the by-pass variation in the control methods can improve the economy of temperature-controlled EFMT at part load but has no benefits when using speed control.


Author(s):  
F Fantozzi ◽  
B D'Alessandro ◽  
G Bidini

Sustainability is one of the main goals to achieve in order to guarantee a future for future generations and requires, among other issues, the recourse to renewable energy sources and the minimization of waste production. These two issues are contemporarily achieved when converting waste and residual biomass into energy. This paper presents an innovative concept for energy conversion of the abovementioned residual fuels; it combines a rotary-kiln pyrolyser, where the residual energy sources are converted into a medium lower heating value (LHV) syngas, with a gas turbine that produces energy, and also provides waste heat to maintain the endothermic pyrolysis reaction. Byproducts of the reaction include char and tars that have an interesting energetic content and may also be used to provide supplementary heat to the process. Through software modelling the paper analyses the influence on performance of main thermodynamic parameters, showing the possibilities of reaching an optimum for different working conditions that are characteristic of different sizes of gas turbines. This is interesting both for medium-to-big size power plants, where the IPRP efficiency is comparable to a grate-based incinerator, but at lower investment costs, and in the micro-small scale, for which there is no available technology on the market.


2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Piotr Żymełka ◽  
Marcin Szega ◽  
Paweł Madejski

Abstract At present, power systems based on gas turbines are mainly used for electricity and heat generation. Gas turbines are used in industrial and institutional applications due to high-temperature exhaust, which can be used for heating, drying, or process steam production. The combined cycle gas turbine plants are a mature technology with high reliability and offering rapid response to changing demand for electricity and heat. The combination of a gas turbine with a heat recovery system and a heat accumulator makes the combined heat and power (CHP) plant a flexible unit. The paper presents the optimization tool for the planning process of electricity and heat production in the gas-fired CHP plant with a heat accumulator. The detailed mathematical model of the analyzed cogeneration plant was developed with the EBSILON®Professional and verified based on the results from on-site tests and warranty measurements. The implemented optimization algorithm is used to maximize the profits of the CHP plant operation. The presented solution is based on an evolutionary algorithm. The optimization algorithm is applied to the production determination for the day-ahead planning horizon, with 1-h time step. The obtained results show that the developed optimization model is a reliable and efficient tool for production planning in a CHP plant with gas turbines. The comparative exergy analysis for different technologies of heat recovery from gas turbine exhaust gases was performed to evaluate the quality of the energy conversion process in the CHP plant.


Author(s):  
G. A. K. Crommelin

Over the last few years a number of papers have discussed the progress on studies and thoughts on small-scale nuclear power. Nuclear power conversion systems aiming for the t of the non-utility markets, such as the stand-alone heat generation, Combined Heat & Power production, stand-alone electricity conversion and ship propulsion. The design of these installations must fully comply with the philosophies as are common in these markets, where the expression “the engine is a means to an end” applies. So design to cost, design to be operated by non professional energy producers, to be managed by a pool-management system, maintained, repaired and overhauled by replacement, etc. The paper will discuss such a design. So far all papers mentioned have discussed the gas turbine directly coupled to the heat source. However the helium turbine is considered quite a challenge for the gas turbine industry, so alternatives had to be found. At the moment the possibilities of gas turbines with an indirect heat source (to burn refuse, wood, refinery waste, etc.) are getting much more attention. The paper therefore will discuss how an inherently safe, well proven, nuclear heat source can be coupled by an Intermediate Heat Exchanger to a recuperative, existing but adapted gas turbine.


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