Wyniki wyszukiwania - BazTech

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Investigation of a combined gas-steam system with flue gas recirculation

Chmielniak T., Mońka P., Pilarz P.

Chemical and Process Engineering

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2016

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Vol. 37, nr 2

305-316

EN

This article presents changes in the operating parameters of a combined gas-steam cycle with a CO2 capture installation and flue gas recirculation. Parametric equations are solved in a purpose-built mathematical model of the system using the Ebsilon Professional code. Recirculated flue gases from the heat recovery boiler outlet, after being cooled and dried, are fed together with primary air into the mixer and then into the gas turbine compressor. This leads to an increase in carbon dioxide concentration in the flue gases fed into the CO2 capture installation from 7.12 to 15.7%. As a consequence, there is a reduction in the demand for heat in the form of steam extracted from the turbine for the amine solution regeneration in the CO2 capture reactor. In addition, the flue gas recirculation involves a rise in the flue gas temperature (by 18 K) at the heat recovery boiler inlet and makes it possible to produce more steam. These changes ontribute to an increase in net electricity generation efficiency by 1%. The proposed model and the obtained results of numerical simulations are useful in the analysis of combined gas-steam cycles integrated with carbon dioxide separation from flue gases.

2

Thermodynamic modeling of high-temperature combined cycle for hydrogen and electricity co-production

Dudek M., Jaszczur M., Kolenda Z., Polepszyc I.

Computer Assisted Methods in Engineering and Science

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2015

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Vol. 22, no. 4

315--327

EN

The high (HTGR) and very high (VHTR) temperature nuclear reactors are the most innovative designs and belong to the most advanced fourth generation gas-cooled reactor technology. These types of reactors are designed to have an outlet temperature between 800–1000°C for the HTGR and the VHTR respectively. Such systems are able to generate electrical energy and supply process heat in a broad spectrum of high temperature and energy-intensive non-electric and thermal processes. In this paper, a numerical analysis of high temperature the HTGR/VHTR combined cycle with co-production of hydrogen and electricity is conducted. The presented cycle consists of three subsidiary circuits with gas turbine and two steam turbines for electric energy generation, and two heat exchangers for hydrogen production at high or medium temperature. The results show that such a combination allows a significant increase of thermal efficiency to about 50% at the reactor outlet temperature of 1273 K and a decrease in cost of hydrogen production.

3

Loading CCGT for industrial extraction steam turbines

Zaryankin A. E., Rogalev A. N., Zaryankin V. A., Kocherova A. A., Komarov I. I.

Journal of Power Technologies

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2013

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Vol. 93, nr 5

303--307

EN

This paper considers the issue of industrial bleed steam utilization to increase the capacity of combined cycle gas turbine plants. The feasibility of transition to a steam turbine compressor drive is also investigated.

4

Steam bottoming cycles offshore - challenges and possibilities

Nord L. O., Bolland O.

Journal of Power Technologies

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2012

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Vol. 92, nr 3

201--207

EN

This paper addresses the challenges and possibilities related to offshore steam bottoming cycles with a special focus on once-through heat recovery steam generators (HRSGs). The main focus of the paper is to investigate the compromise between weight and efficiency of the HRSG by process simulation. The cost per installed kg of equipment is high offshore. Therefore, any bottoming cycle, applied to the back-end of the gas turbine, needs to be compact, yet sufficiently efficient. Important parameters to make the HRSG compact were the number of steam pressure levels, the HRSG technology, the flue gas pressure drop in the HRSG, and the pinch-point temperature difference. While selecting the parameters as a compromise between weight and efficiency, the combined cycle net plant efficiency was found to be approximately 50% with a power output of 43 MW. The steam turbine gross power output was 11 MW or about 25% of the total combined cycle plant gross power output. These results were compared to an onshore reference plant model which utilized the same type of aeroderivative gas turbine. The weight of the offshore once-through HRSG was about one third of the onshore HRSG. The net plant efficiency was 3%-points lower for the offshore system.