Performance Optimization of Advanced H2/Air Cycle Power Plants Based on Natural Gas Partial Oxidation

Author(s):  
Marco Gambini ◽  
Michela Vellini

In this paper the overall performance of an advanced combined cycle (CC) and of a new advanced mixed cycle (AMC), fed by hydrogen-rich fuel gas, has been evaluated. Obviously, hydrogen must be produced and here we have chosen the partial oxidation of natural gas for its production, quantifying all the thermal and electric requirements. At first, a simple combination between hydrogen production section and power section is performed. In fact, the heat loads of the first section can be satisfied (nearly completely) by using the various raw syngas cooling, but in this case it is not possible to use any part of this heat in the power section. The final result is an overall efficiency of about 44%. Then, by using the Pinch Technology, a more efficient, even if more complex, solution can be conceived; in this case the overall efficiency becomes very interesting especially for the AMC (efficiency is over 50%). This result is very important with the view of a transition toward a “clean energy” economy, based on an energy carrier such as hydrogen.

Author(s):  
M. Gambini ◽  
M. Vellini

In this paper the overall performance of a new advanced mixed cycle (AMC), fed by hydrogen-rich fuel gas, has been evaluated. Obviously, hydrogen must be produced and here we have chosen the coal gasification for its production, quantifying all the thermal and electric requirements. At first, a simple combination between hydrogen production section and power section is performed. In fact, the heat loads of the first section can be satisfied by using the various raw syngas cooling, without using some material streams taken from the power section, but also without using part of heat, available in the production section and rejected into the environment, in the power section. The final result is very poor: over 34%. Then, by using the Pinch Technology, a more efficient, even if more complex, solution can be conceived: in this case the overall efficiency is very interesting: 39%. These results are very similar to those of a combined cycle power plant, equipped with the same systems and analyzed under the same hypotheses. The final result is very important because the “clean” use of coal in new power plant types must be properly investigated: in fact coal is the most abundant and the cheapest fossil fuel available on earth; moreover, hydrogen production, by using coal, is an interesting outlook because hydrogen has the potential to become the main energy carrier in a future sustainable energy economy.


Author(s):  
Marco Gambini ◽  
Michela Vellini

In this paper two options for H2 production, by means of fossil fuels, are presented and their performances are evaluated when they are integrated with advanced H2/air cycles. In this investigation two different schemes have been analyzed: an advanced combined cycle power plant (CC) and a new advanced mixed cycle power plant (AMC). The two methods for producing H2 are as follows: • partial oxidation of methane; • gasification of coal. These hydrogen production plants require material and energetic integrations with the power section and the best interconnections must be investigated in order to obtain good overall performance. With reference to thermodynamic and economic performance, significant comparisons have been made between the above mentioned reference plants. An efficiency decrease and an increase in the cost of electricity have been obtained when power plants are equipped with a fossil fuel decarbonization section. The main results of the performed investigation are quite variable among the different H2 production technologies here considered: the efficiency decreases in a range of 5.5 percentage points to nearly 10 for the partial oxidation of the natural gas and in a range of 6.2–6.4 percentage points for the coal gasification. The electricity production cost increases in a range of about 33–37% for the first option and in a range of about 24–32% for the second one. The clean use of coal seems to have very good potentiality because, in comparison with natural gas decarbonisation, it allows lower energy penalizations (about 6 percentage points) and lower economic increases (about 24% for the CC).


2000 ◽  
Vol 124 (1) ◽  
pp. 89-95 ◽  
Author(s):  
G. Lozza ◽  
P. Chiesa

This paper discusses novel schemes of combined cycle, where natural gas is chemically treated to remove carbon, rather than being directly used as fuel. Carbon conversion to CO2 is achieved before gas turbine combustion. The first part of the paper discussed plant configurations based on natural gas partial oxidation to produce carbon monoxide, converted to carbon dioxide by shift reaction and therefore separated from the fuel gas. The second part will address methane reforming as a starting reaction to achieve the same goal. Plant configuration and performance differs from the previous case because reforming is endothermic and requires high temperature heat and low operating pressure to obtain an elevated carbon conversion. The performance estimation shows that the reformer configuration has a lower efficiency and power output than the systems addressed in Part I. To improve the results, a reheat gas turbine can be used, with different characteristics from commercial machines. The thermodynamic efficiency of the systems of the two papers is compared by an exergetic analysis. The economic performance of natural gas fired power plants including CO2 sequestration is therefore addressed, finding a superiority of the partial oxidation system with chemical absorption. The additional cost of the kWh, due to the ability of CO2 capturing, can be estimated at about 13–14 mill$/kWh.


Author(s):  
Marco Gambini ◽  
Michela Vellini

In this paper two options for H2 production, by means of natural gas, are presented and their performances are evaluated when they are integrated with advanced H2/air cycles. In this investigation two different schemes have been analysed: an advanced combined cycle power plant (CC) and a new advanced mixed cycle power plant (AMC). The two methods for producing H2 are as follows: • steam methane reforming: it is the simplest and potentially the most economic method for producing hydrogen in the foreseeable future; • partial oxidation of methane: it could offer an energy advantage because this method reduces energy requirement of the reforming process. These hydrogen production plants require material and energetic integrations with power section and the best interconnections must be investigated in order to obtain good overall performance. With reference to thermodynamic and economic performance, significant comparisons have been made between the above introduced reference plants. An efficiency decrease and an increase in the cost of electricity has been obtained when power plants are equipped with a natural gas decarbonisation section. The main results of the performed investigation are quite variable among the different H2 production technologies here considered: the efficiency decreases in a range of 5.5 percentage points to nearly 10 for the partial oxidation of the natural gas and in a range of 8.8 percentage points to over 12 for the steam methane reforming. The electricity production cost increases in a range of about 41–42% for the first option and in a range of about 34–38% for the second one. The AMC, coupled with partial oxidation, stands out among the other power plant solutions here analysed because it exhibits the highest net efficiency and the lowest final specific CO2 emission. In addition to this, economic impact is favourable when AMC is equipped with systems for H2 production based on partial oxidation of natural gas.


Author(s):  
Giovanni Lozza ◽  
Paolo Chiesa

This paper discusses novel schemes of combined cycle, where natural gas is chemically treated to remove carbon, rather than being directly used as fuel. Carbon conversion to CO2 is achieved before gas turbine combustion. The first part of the paper discussed plant configurations based on natural gas partial oxidation to produce carbon monoxide, converted to carbon dioxide by shift reaction and therefore separated from the fuel gas. The second part will address methane reforming as a starting reaction to achieve the same goal. Plant configuration and performance differs from previous case because reforming is endothermic and requires high temperature heat and low operating pressure to obtain an elevated carbon conversion. The performance estimation shows that the reformer configuration has a lower efficiency and power output than the systems addressed in Part A. To improve the results, a reheat gas turbine can be used, with different characteristics from commercial machines. The thermodynamic efficiency of the systems of the two papers is compared by an exergetic analysis. The economic performance of natural gas fired power plants including CO2 sequestration are therefore addressed, finding a superiority of the partial oxidation system with chemical absorption. The additional cost of the kWh, due to the ability of CO2 capturing, can be estimated at about 13–14 mill$/kWh.


2007 ◽  
Vol 129 (4) ◽  
pp. 1114-1124 ◽  
Author(s):  
Marco Gambini ◽  
Michela Vellini

In this paper two options for H2 production, by means of natural gas, are presented and their performances are evaluated when they are integrated with advanced H2/air cycles. In this investigation two different schemes have been analyzed: an advanced combined cycle power plant (CC) and a new advanced mixed cycle power plant (AMC). The two methods for producing H2 are as follows: (1) steam methane reforming: it is the simplest and potentially the most economic method for producing hydrogen in the foreseeable future; and (2) partial oxidation of methane: it could offer an energy advantage because this method reduces the energy requirement of the reforming process. These hydrogen production plants require material and energetic integrations with power section and the best interconnections must be investigated in order to obtain good overall performance. With reference to thermodynamic and economic performance, significant comparisons have been made between the above introduced reference plants. An efficiency decrease and an increase in the cost of electricity has been obtained when power plants are equipped with a natural gas decarbonization section. The main results of the performed investigation are quite variable among the different H2 production technologies here considered: the efficiency decreases in a range of 5.5 percentage points to nearly 10 for the partial oxidation of the natural gas and in a range of about 9 percentage points to over 12 for the steam methane reforming. The electricity production cost increases in a range of about 41–42% for the first option and in a range of about 34–38% for the second one. The AMC, coupled with partial oxidation, stands out among the other power plant solutions here analyzed because it exhibits the highest net efficiency and the lowest final specific CO2 emission. In addition to this, economic impact is favorable when AMC is equipped with systems for H2 production based on partial oxidation of natural gas.


2013 ◽  
Author(s):  
Norma J. Kuehn ◽  
Kajal Mukherjee ◽  
Paul Phiambolis ◽  
Lora L. Pinkerton ◽  
Elsy Varghese ◽  
...  

Author(s):  
Thormod Andersen ◽  
Hanne M. Kvamsdal ◽  
Olav Bolland

A concept for capturing and sequestering CO2 from a natural gas fired combined cycle power plant is presented. The present approach is to decarbonise the fuel prior to combustion by reforming natural gas, producing a hydrogen-rich fuel. The reforming process consists of an air-blown pressurised auto-thermal reformer that produces a gas containing H2, CO and a small fraction of CH4 as combustible components. The gas is then led through a water gas shift reactor, where the equilibrium of CO and H2O is shifted towards CO2 and H2. The CO2 is then captured from the resulting gas by chemical absorption. The gas turbine of this system is then fed with a fuel gas containing approximately 50% H2. In order to achieve acceptable level of fuel-to-electricity conversion efficiency, this kind of process is attractive because of the possibility of process integration between the combined cycle and the reforming process. A comparison is made between a “standard” combined cycle and the current process with CO2-removal. This study also comprise an investigation of using a lower pressure level in the reforming section than in the gas turbine combustor and the impact of reduced steam/carbon ratio in the main reformer. The impact on gas turbine operation because of massive air bleed and the use of a hydrogen rich fuel is discussed.


Energy ◽  
2019 ◽  
Vol 168 ◽  
pp. 477-491 ◽  
Author(s):  
A. Gangoli Rao ◽  
F.S.C. van den Oudenalder ◽  
S.A. Klein

Sign in / Sign up

Export Citation Format

Share Document