Modelling of low-pressure steam turbines operating at very low flowrates: A multiblock approach

Mambro, Antonio; Galloni, Enzo; Congiu, Francesco; Maraone, N.

doi:10.1016/j.applthermaleng.2019.113782

Cited by 12 publications

(6 citation statements)

References 10 publications

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“…Wang [44] optimized the operation of a turbine's regulating valve based on data mining and succeed in improving the economy of the whole plant unit. Mambro et al [45] predicted the maximum fluid temperature, the velocity field and the power exchange between fluid and blades when a low-pressure turbine worked at off-design conditions by a multiblock approach. Pumps and induced draft fans are components of minor potential to further exergy utilization, only sharing 0.76% in the total improvement potential, but they can also be optimized by installing variable speed drives [3].…”

Section: Exergy Improvement Potentialmentioning

confidence: 99%

Energy, Exergy and Economic Analyses of a Combined Heating and Power System with Turbine-Driving Fans and Pumps in Northeast China

Gao

Zhang

et al. 2020

Energies

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The combined heating and power (CHP) system with turbine-driving fans and pumps is more efficient and economical in meeting heat demand in cold areas, however, there are no detailed studies that investigate its thermodynamic performance, improvement possibilities and economy. In this paper, the energy, exergy and economic analysis of a CHP system with turbine-driving fans and pumps operated in Northeast China were conducted to provide insights into improvement options. It is revealed that the boiler is the main source of exergy destruction, followed by the steam-water heat exchangers (SWHE), temperature and pressure reducer (TPR), turbines, and deaerator. The energy and exergy efficiencies of the system are 89.72% and 10.07%, while the boiler’s are 84.89% and 30.04%. The thermodynamic performance of the boiler and turbines are compared with other studies, and the inefficiencies of major components are analyzed and some advice for further improvement is given. As the reference state changes, the main conclusions stay the same. The turbine-driving mode saves an electricity cost of 16,654.08 yuan on 15 December 2018. The effect of electricity price and on-grid price on the saved daily electricity cost is investigated and it proves that the turbine-driving mode is more economical in China.

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Section: Exergy Improvement Potentialmentioning

confidence: 99%

Energy, Exergy and Economic Analyses of a Combined Heating and Power System with Turbine-Driving Fans and Pumps in Northeast China

Gao

Zhang

et al. 2020

Energies

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“…Lu et al [17] and Agrež et al [18] also analyzed steam throttling in steam turbine valves and concluded the amount of entropy generated during thermodynamic transformation is closely related to the degree of steam throttling. Wang et al [19], Mambro et al [20], and Guo et al [21] analyzed the steam turbine at minimum flows, where they also found increased entropy generation and a consequently decreased cycle efficiency. As already mentioned, the expansion curves for various modes of steam turbine opera-tion constructed using the real process data confirm exactly this.…”

Section: Discussionmentioning

confidence: 99%

Off-design flow analysis of cogeneration steam turbine with real process data

2022

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This paper presents the concept of reconstruction of the existing coal-fired combined heat and power plant to comply with new European environmental policies. The existing coal-fired boiler will be replaced by two new dual pressure heat recovery steam generators, which will utilize the exhaust gas heat from two new gas turbines. The steam from the heat recovery steam generators will be fed to the existing steam turbine. After the reconstruction, the nominal turbine inlet steam mass-flow of 40 kg/s will be reduced to 30 kg/s. During periods of low heat demand, only one gas turbine and one heat recovery steam generator will be in operation and the live steam mass-flow may drop even to 12 kg/s. Prior to the reconstruction, dedicated tests of the existing steam turbine were carried out using the steam from the existing coal-fired boiler. The goal of the test was to verify the viability of operation with such an extremely low mass-flow. The results of tests show that such operation is possible but inefficient from a power generation point of view. Besides this, the turbine control algorithm needs to be accommodated to this extreme operating regime and additional measures like displacement of the extraction points and steam cooling will be required to control the temperature of the steam extractions. The novelty of this paper is using real pre-reconstruction process data for the assessment of feasibility and efficiency of the post-reconstruction operation of a combined heat and power turbine.

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“…An example of this is the use of a linear characteristic in turbines. Steam turbine modelling is a complex problem [19], but analysis of operational data from existing WtE plants has shown that maintaining a linear characteristic allows for sufficient model accuracy.…”

Section: Step 1-optimizationmentioning

confidence: 99%

Modelling of Change in Fuel Mix within a District Heating Network

et al. 2022

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Changing the fuel mix used in the heating industry, i.e., switching to greener fuels, is one of the possible solutions to prevent rising costs for final consumers in the context of rising emission allowance prices. This paper presents a methodology that offers the possibility to perform a comprehensive technical and economic assessment of a theoretical solution—changing the fuel mix of centralized heating sources—and other strategic decisions within a district’s heating systems. Emphasis is placed on fuels with a negative price, such as municipal waste. The presented approach can also be used to assess the effect of other significant changes related to the configuration of district heating systems on the economy of the plant, such as the impact of a decrease in heat demand and implementation of a steam turbine. The key benefit of this paper is an approach based on mathematical modelling of the operation of individual boilers with different operating parameters in terms of their start-up, shutdown, and mode of operation. A unique approach of optimizing an operation’s schedule using dynamic programming is presented, which enables the selection of a suitable solution for the configuration of binary variables in consecutive time steps. In this way, it is possible to achieve a more accurate estimate of the economics of the facility at the strategic planning stage that will consider the real operational capabilities of the heat source given its technical limitations. Using this approach, up to a 4% reduction in variable operating costs was achieved in the model case, when compared to static time interval planning.

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Modelling of low-pressure steam turbines operating at very low flowrates: A multiblock approach

Cited by 12 publications

References 10 publications

Energy, Exergy and Economic Analyses of a Combined Heating and Power System with Turbine-Driving Fans and Pumps in Northeast China

Energy, Exergy and Economic Analyses of a Combined Heating and Power System with Turbine-Driving Fans and Pumps in Northeast China

Off-design flow analysis of cogeneration steam turbine with real process data

Modelling of Change in Fuel Mix within a District Heating Network

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