Natural Gas Decarbonisation Technologies for Advanced Power Plants

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.

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.


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).


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

In this paper two options for H2 production by means of fossil fuels are presented, evaluating their performance when integrated with advanced H2/air cycles. The investigation has been developed with reference to two different schemes, representative both of consolidated technology (combined cycle power plants) and of innovative technology (a new advance mixed cycle, named AMC). The two methods, here considered, to produce H2 are: • coal gasification: it permits transformation of a solid fuel into a gaseous one, by means of partial combustion reactions; • steam-methane reforming: it is the simplest and potentially the most economic method for producing hydrogen in the foreseeable future. These hydrogen production plants require material and energy integrations with the power section, and the best connections must be investigated in order to obtain good overall performance. The main results of the performed investigation are quite variable among the different H2 production options here considered: for example the efficiency value is over 34% for power plants coupled with coal decarbonization system, while it is in a range of 45–48% for power plants coupled with natural gas decarbonization. These differences are similar to those attainable by advanced combined cycle power plants fuelled by natural gas (traditional CC) and coal (IGCC). In other words, the decarbonization of different fossil fuels involves the same efficiency penalty related to the use of different fossil fuel in advanced cycle power plants (from CC to IGCC for example). The CO2 specific emissions depend on the fossil fuel type and the overall efficiency: adopting a removal efficiency of 90% in the CO2 absorption systems, the CO2 emission reduction is 87% and 82% in the coal gasification and in the steam-methane reforming respectively.


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 steam-methane reforming for its production, quantifying all the thermal and electric requirements. At first, the thermodynamic performance of this cycle has been investigated in comparison with that attainable by combined cycle power plants (CC). Then, the power plants have been integrated with the fuel production system. Including all the material and energetic flows, the overall performance has been evaluated. The main result of the performed investigation is that, while the two power plants attain the same efficiency level without H2 production requirements (about 56% for AMC and 55.8% for CC), the AMC power plant achieves a net electric efficiency of about 48% when integrated with H2 production plant: it is about 3 points higher than the efficiency evaluated for the CC equipped with the same H2 production plant (about 45%). The final carbon dioxide emissions are about 0.0742 and 0.079 kg/kWh for AMC and CC respectively.


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):  
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.


Author(s):  
Angineh Zohrabian ◽  
Mohammad Mansouri Majoumerd ◽  
Mohammad Soltanieh ◽  
Øystein Arild

In order to achieve the international climate goals and to keep the global temperature increase below 2 °C, carbon capture and storage in large point sources of CO2 emissions has received considerable attention. In recent years, mitigation of CO2 emissions from the power sector has been studied extensively whereas other industrial point source emitters such as hydrogen industry have also great potential for CO2 abatement. This study aims to draw an updated comparison between different hydrogen and power cogeneration systems using natural gas and coal as feedstock. The goal is to show the relative advantage of cogeneration systems with respect to CO2 emission reduction costs. Accordingly, the Reference Case is selected as a large-scale H2 production system with CO2 venting using natural gas based on steam methane reforming. In this work, H2 and electricity cogeneration with CO2 capture based on auto-thermal reforming of natural gas has been simulated using ASPEN Plus™, while the cost and performance indicators for the plant based on steam methane reforming of natural gas and the coal-based plants have been adopted from the literature. Using a consistent approach, different plants are compared techno-economically. A sensitivity analysis has also been performed with variation in the most important input parameters including natural gas price (2–8 $/GJ), coal price (1–4 $/GJ), electricity price (30–90 $/MWh) and capacity factors (85–50%) and the results are presented here. The results demonstrate that the total efficiency of the system is slightly higher in natural gas-based systems than in coal-based systems. The results also indicate that although H2 production cost increases with power cogeneration and CO2 capture, cogeneration is a promising and attractive alternative for clean power generation. The highest sensitivity of the results has been observed for the fuel price.


2021 ◽  
Author(s):  
Basavaraja Revappa Jayadevappa

Abstract Operation of power plants in carbon dioxide capture and non-capture modes and energy penalty or energy utilization in such operations are of great significance. This work reports on two gas fired pressurized chemical-looping combustion power plant lay-outs with two inbuilt modes of flue gas exit namely, with carbon dioxide capture mode and second mode is letting flue gas (consists carbon dioxide and water) without capturing carbon dioxide. In the non-CCS mode, higher thermal efficiencies of 54.06% and 52.63% efficiencies are obtained with natural gas and syngas. In carbon capture mode, a net thermal efficiency of 52.13% is obtained with natural gas and 48.78% with syngas. The operating pressure of air reactor is taken to be 13 bar for realistic operational considerations and that of fuel reactor is 11.5 bar. Two power plant lay-outs developed based combined cycle CLC mode for natural gas and syngas fuels. A single lay-out is developed for two fuels with possible retrofit for dual fuel operation. The CLC Power plants can be operated with two modes of flue gas exit options and these operational options makes them higher thermal efficient power plants.


Author(s):  
Radin Diana R. Ahmad ◽  
Tiong Sieh Kiong ◽  
Sazalina Zakaria ◽  
Ahmad Rosly Abbas ◽  
Chen Chai Phing ◽  
...  

Three different power plants have been assessed in terms of energy conversion efficiency and GHGs emission rate. The power plants are coal power plant, natural gas power plant and biomass power plant. The assessments are made by collecting fuels consumption data and generated electricity data of each power plant. In addition to the data collection, observation on operational practices have also been carried out. The energy conversion efficiency and the GHGs emission rate for all power plants are recorded to be lower than the typical values proposed by the literature. The biomass power plant recorded the lowest energy conversion efficiency at 6.47 %. Meanwhile, the natural gas power plant utilizing the combined cycle gas turbine technology recorded the highest overall energy conversion efficiency at 48.35 % and rated to emit GHGs at 0.32 kg CO2e per kWh.


Sign in / Sign up

Export Citation Format

Share Document