scholarly journals Life Cycle Assessment of Cogeneration Systems Using Raw and Torrefied Dichrostachys Cinerea (L.) Wight & Arm. (Marabou).

2021 ◽  
Author(s):  
Yasmani Alba ◽  
Maylier Pérez-Gil ◽  
Ernesto L. Barrera ◽  
Yannay Casas-Ledón ◽  
Luis Ernesto Arteaga-Pérez
Keyword(s):  
Steam Turbine ◽  
Water Consumption ◽  
Electricity Generation ◽  
Back Pressure ◽  
Mineral Fertilizers ◽  
Dichrostachys Cinerea ◽  
Damage Category ◽  
Study Results ◽  
Pressure Steam ◽  
The Impact

Abstract Purpose This study aims to assess environmentally three different alternatives related to the valorization of Dichrostachys cinerea (L.) Wight & Arm. (marabou), identified as an invasive tree, as a feedstock for cogeneration facilities installed in the sugarcane industry in Cuba. The alternatives are (A-1) Electricity generation from marabou in a conventional back-pressure steam turbine cycle, (A-2) Electricity generation from torrefied marabou in a back-pressure steam turbine cycle, and (A-3) Electricity generation from torrefied marabou using extraction-condensing turbines.Methods SimaPro 9.0.0.35 software was used for the modeling of the inventory, based on different operational parameters. The ReCiPe environmental impact assessment method was used in the hierarchical perspective, assessing 18 impact categories (midpoint), and 3 damage categories (endpoint).Results and discussion The results demonstrated that A-3 shows the lower environmental impacts (Fine Particulate Matter Formation, Terrestrial Acidification, and Water Consumption) as compared to A-2 and A-1. This performance is explained by a lower normalized marabou consumption (1.85 kg marabou/kWh generated), and lower emissions associated with marabou harvesting, transportation, and processing. The cogeneration stage was the main contributor to the environmental burdens in Water Consumption (100% in A-1; 87% in A-2 and A-3). Marine Ecotoxicity was the impact category with better environmental performance due to the substitution of synthetic mineral fertilizers by ashes produced during combustion. The human health damage category reached the higher impacts on the torrefaction subsystem in the A-3 scenario, representing over 94% of the total environmental burden of the process. PM<10, NO2, and SO2 contributed the most over this damage category, mainly in marabou combustion, causing injuries in respiratory systems by aspiration of organic compounds.Conclusions The use of more efficient technology (extraction-condensing steam turbine), using torrefied marabou as feedstock, compared with the previous alternatives, impacts beneficially on the environment. Thus, a combination of marabou torrefaction with cogeneration facilities in sugarcane industries can be considered as an environmental-friendly technology in the Cuban context. The current study results will help decision-makers implement more sustainable policies in the Cuban energy sector, using marabou as feedstock as an attractive bioenergy route pathway.

scholarly journals The Impact of Coal and Biomass Co-Firing on the Economy of Power Plant Carbon Capture

2020 ◽  
Vol 12 (2) ◽  
pp. 67-77
Author(s):  
Quan Zhuang ◽  
Philip Geddis ◽  
Bruce Clements
Keyword(s):  
Economic Evaluation ◽  
Power Plant ◽  
Incremental Cost ◽  
Co2 Capture ◽  
Electricity Generation ◽  
Carbon Capture ◽  
Lower Cost ◽  
Study Results ◽  
And Performance ◽  
The Impact

A detailed economic evaluation was carried out to determine the impact of biomass and coal co-firing on power plant carbon capture by methods of plants equipment designing factors and performance, and the sum up of the associated breakdowns of CAPEX and OPEX. Based on the assumptions of the CO2 neutrality of biomass and likely governmental incentives to reduce CO2 emissions, the study results show that biomass and coal co-firing would result in both lower cost of carbon avoided (carbon capture) and lower incremental cost of electricity generation when MEA solvent carbon capture is applied. Two scenarios for co-firing with carbon capture, 30% biomass blending and 90% or 60% CO2 capture from stack, indicate different preference depending on lower or higher incentives.

Performance improvement of low-pressure cylinder in high back pressure steam turbine for direct heating

2021 ◽  
Vol 182 ◽  
pp. 116170
Author(s):  
Xiaodong Zhao ◽  
Ang Li ◽  
Youjun Zhang ◽  
Liqun Ma ◽  
Zhihua Ge ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Performance Improvement ◽  
Low Pressure ◽  
Back Pressure ◽  
Direct Heating ◽  
Pressure Steam ◽  
Pressure Cylinder

Effects of Steam Reheat in Advanced Steam Injected Gas Turbine Cycles

1998 ◽  
Author(s):  
A. Hofstädter ◽  
H. U. Frutschi ◽  
H. Haselbacher
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Power Plants ◽  
Steam Injection ◽  
Combined Cycle ◽  
Back Pressure ◽  
Turbine Efficiency ◽  
Pressure Steam ◽  
Additional Improvement ◽  
Gas Turbine Exhaust

Steam injection is a well-known principle for increasing gas turbine efficiency by taking advantage of the relatively high gas turbine exhaust temperatures. Unfortunately, performance is not sufficiently improved compared with alternative bottoming cycles. However, previously investigated supplements to the STIG-principle — such as sequential combustion and consideration of a back pressure steam turbine — led to a remarkable increase in efficiency. The cycle presented in this paper includes a further improvement: The steam, which exits from the back pressure steam turbine at a rather low temperature, is no longer led directly into the combustion chamber. Instead, it reenters the boiler to be further superheated. This modification yields additional improvement of the thermal efficiency due to a significant reduction of fuel consumption. Taking into account the simpler design compared with combined-cycle power plants, the described type of an advanced STIG-cycle (A-STIG) could represent an interesting alternative regarding peak and medium load power plants.

Application Study on Low Vacuum Circulating Water Heat Supply of a 50 MW Turbine

2014 ◽  
Vol 953-954 ◽  
pp. 896-899 ◽  
Author(s):  
Shan Tu ◽  
Qi Zhou ◽  
Jian Liu Jian ◽  
Cong Qiang Ding ◽  
Shu Ming Wu
Keyword(s):  
Energy Saving ◽  
Steam Turbine ◽  
Heat Supply ◽  
Back Pressure ◽  
Coal Consumption ◽  
Exhaust Temperature ◽  
Circulating Water ◽  
Air Inlet ◽  
Pollution Emissions ◽  
The Impact

This topic mainly research the high back pressure heat supply technology of steam turbine generator unit and the correlation analysis of turbine under high back pressure operating condition. High back pressure heat supply is an energy saving technology developed in order to meet the requirements of energy saving and environmental protection. This technology can not only reduce the cold end losses to improve the thermal efficiency of power plant, but also decrease the energy loss and pollution emissions because it take the place of traditional heating boiler. High back pressure heat supply of steam turbine is to increase the quantity of air inlet and outlet as well as exhaust temperature through improving turbine back pressure. For condensing steam turbine unit of 50 MW studied in this article, back pressure of which rise to 0.032MPa from 0.0046MPa, and the exhaust temperature will increase to 70 °C respectively. Through the calculation of rated condition and variable condition, we can obtain the impact to the unit due to the change of back pressure, and for unit of 50 MW can reduce 30876.9 tons of standard coal consumption in a heating period. It can also decrease the emission of carbon dioxide, sulfur dioxide, smoke and ashes, which effect of energy saving and emission reducing is very obvious.

Turbo-S.T.I.G.: The Turbocharged Steam Injected Gas Turbine Cycle

1989 ◽  
Author(s):  
R. W. Foster-Pegg
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Complete Recovery ◽  
Back Pressure ◽  
Gas Turbine Combustor ◽  
Exhaust Heat ◽  
Pressure Steam ◽  
Cycle Maximum ◽  
Gas Turbine Cycle

In this Steam Injected Gas turbine cycle, maximum steam is raised with exhaust heat at the highest practical pressure for expansion in a back pressure steam turbine before injection into the gas turbine combustor. Additional steam is raised at lower pressure and injected into the combustor, to effect more complete recovery of heat. The back pressure steam turbine drives a topping air compressor which raises the gas cycle pressure ratio. This allows the standard gas turbine blading to accommodate the additional steam flow because of the higher pressure and density of the gas.

The Influence of Roughness on a High-Pressure Steam Turbine Stage: An Experimental and Numerical Study

2014 ◽  
Author(s):  
Juri Bellucci ◽  
Filippo Rubechini ◽  
Michele Marconcini ◽  
Andrea Arnone ◽  
Lorenzo Arcangeli ◽  
...  
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Numerical Study ◽  
Practical Interest ◽  
Numerical Approach ◽  
Fine Tuning ◽  
High Pressure Steam ◽  
Pressure Steam ◽  
High Pressure Stage ◽  
The Impact

This work deals with the influence of roughness on high-pressure steam turbine stages. It is divided in three parts. In the first one, an experimental campaign on a linear cascade is described, in which blade losses are measured for different values of surface roughness and in a range of Reynolds numbers of practical interest. The second part is devoted to the basic aspects of the numerical approach, and consists of a detailed discussion of the roughness models used for computations. The fidelity of such models is then tested against measurements, thus allowing their fine-tuning and proving their reliability. Finally, comprehensive CFD analysis is carried out on a high-pressure stage, in order to investigate the influence of roughness on the losses over the entire stage operating envelope. Unsteady effects that may affect the influence of the roughness, such as the upcoming wakes on the rotor blade, are taken into account, and the impact of transition-related aspects on the losses is discussed.

Numerical and Experimental Investigation of Axial Gap Variation in High-Pressure Steam Turbine Stages

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Juri Bellucci ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Lorenzo Arcangeli ◽  
Nicola Maceli ◽  
...  
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Flow Angle ◽  
High Pressure Steam ◽  
Aspect Ratios ◽  
Pressure Steam ◽  
The Impact

This work aims at investigating the impact of axial gap variation on aerodynamic performance of a high-pressure steam turbine stage. Numerical and experimental campaigns were conducted on a 1.5-stage of a reaction steam turbine. This low speed test rig was designed and operated in different operating conditions. Two different configurations were studied in which blades axial gap was varied in a range from 40% to 95% of the blade axial chord. Numerical analyses were carried out by means of three-dimensional, viscous, unsteady simulations, adopting measured inlet/outlet boundary conditions. Two sets of measurements were performed: steady measurements, from one hand, for global performance estimation of the whole turbine, such as efficiency, mass flow, and stage work; steady and unsteady measurements, on the other hand, were performed downstream of rotor row, in order to characterize the flow structures in this region. The fidelity of computational setup was proven by comparing numerical results to measurements. Main performance curves and spanwise distributions have shown a good agreement in terms of both shape of curves/distributions and absolute values. Moreover, the comparison of two-dimensional maps downstream of rotor row has shown similar structures of the flow field. Finally, a comprehensive study of the axial gap effect on stage aerodynamic performance was carried out for four blade spacings (10%, 25%, 40%, and 95% of S1 axial chord) and five aspect ratios (1.0, 1.6, 3, 4, and 5). The results pointed out how unsteady interaction between blade rows affects stage operation, in terms of pressure and flow angle distributions, as well as of secondary flows development. The combined effect of these aspects in determining the stage efficiency is investigated and discussed in detail.

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