Integrated Gasification Combined Cycle Systems Research Articles

IGCC Precombustion CO2 Capture Using K2CO3 Solvent and Utilizing the Intercooling Heat Recovered From CO2 Compressors for CO2 Regeneration

CO2 capture (CC) using hot K2CO3 solvent in integrated gasification combined cycle (IGCC) plant is a promising technology for CO2 emission reduction. Based on pilot scale trials, an innovative IGCC system with CC using hot K2CO3 solvent is proposed, in which the intercooling heat between CO2 compressors is recovered for CO2 regeneration (IGCC + CC + HR). Thermodynamic performance and exergy and energy utilization diagram (EUD) analysis are presented. Results show that recovery of the intercooling heat between CO2 compressors reduces the steam extraction requirement from turbines for CO2 regeneration by around 18% and enhances the efficiency of IGCC with CO2 capture (IGCC + CC) plant by 0.3–0.7 percentage points. With 90% CC, the efficiency of the IGCC + CC + HR plant is around 35.4% which is higher than IGCC + CC plant using Selexol technology. Compared to IGCC, the energy penalty for CC in IGCC + CC + HR plant is mainly caused by the exergy losses in CO2 separation (45.2%), water gas shift (WGS) (28.5%), combined cycle (20.7%) and CO2 compression units (5.6%). EUD analysis shows that the IGCC + CC + HR plant realizes good match of the energy levels between the intercooling heat and the recovered steam for CO2 regeneration, thereby obviously reducing the exergy losses in CO2 compression and separation units and improving the plant efficiency. The results presented in this paper confirm the sources causing the energy penalty for CC in IGCC power plant and the new IGCC + CC + HR system helps to reduce the energy penalty for CC in IGCC power plant based on solvent technologies.

Study on a new IGCC (Integrated Gasification Combined Cycle) system with CO2 capture by integrating MCFC (Molten Carbonate Fuel Cell)

In this paper, a new Integrated Gasification Combined Cycle (IGCC) system with less CO2 emission by integrating a Molten Carbonate Fuel Cell (MCFC) to capture CO2 has been proposed. The performance of the new system is compared with other three systems: a conventional IGCC system without CO2 capture, an IGCC system with pre-combustion capture and an IGCC system with oxy-fuel combustion capture. In addition, the effects of the key parameters of MCFC such as CO2 utilization factor, fuel utilization factor and the operating temperature of MCFC on the new system performance have been analyzed and compared. The results show that when the CO2 capture rate is 88%, the efficiency of the new system is about 47.31%, 2.97% higher than that of the IGCC without CO2 capture, 10.45% higher than the IGCC system with pre-combustion CO2 capture, and 12.55% higher than the IGCC system with oxy-fuel combustion CO2 capture. Though the new system has an obvious superiority of thermal performance, its technical economic performance needs be improved with the technical development of MCFC. The research achievements will provide a new way for further study on CO2 capture from IGCC system with lower energy penalty.

CO2 absorption/regeneration enhancement in DI water with suspended nanoparticles for energy conversion application

The integrated gasification combined cycle (IGCC) is getting much more attention due to the rich reserves of coal around the world. In general, the absorption rate of a physical method such as the IGCC system is weaker than that of a chemical method, but it needs much less energy during the regeneration process. In this study, the main objective is to estimate the performance enhancement for CO2 gas absorption and regeneration by using SiO2/DI water and Al2O3/DI water nanofluids. The key parameters are the concentrations of SiO2 and Al2O3 nanoparticles and the system pressure during the regeneration process. It is found that the maximum CO2 absorption and regeneration performance enhancements are 23.5% and 11.8% at 0.01vol% of SiO2 nanoparticles, respectively. However, in the case of Al2O3 nanoparticles, the CO2 absorption performance increases 23.5% at 0.01vol%, but the regeneration performance decreases 11.2% at 0.01vol%, respectively. The enhancement mechanisms for CO2 absorption and regeneration by nanoparticles are summarized and proposed in this study.

Life cycle assessment of a hypothetical Canadian pre-combustion carbon dioxide capture process system

The methodology of life cycle assessment was applied for evaluating the environmental performance of a Saskatchewan lignite integrated gasification combined cycle (IGCC)-based electricity generation plant with and without the pre-combustion CO2 capture process. A comparison between the IGCC systems (with and without CO2 capture) and the competing lignite pulverized coal electricity generating station was conducted to reveal which technology offers more positive environmental effects. The results showed significant reduction of GHG emissions where both post- and pre-combustion CO2 capture processes are applied. With the application of the CO2 removal technology, GHG emissions were reduced by 27–86%. The performances of the IGCC systems were superior to those of the pulverized coal systems. However, in terms of other environmental impacts, multiple environmental trade-offs are involved depending on the capture technology. For the post-combustion CO2 capture process system, it was observed that the environmental impact was shifted from the air compartment to the soil and water compartments. The IGCC systems showed the same tendency of shifting from air pollution to soil and water pollution, but the amount of pollution is less significant. This is likely because the IGCC system operates at higher efficiencies; hence, it requires less fuel and produces fewer emissions.

Techno-economic optimization of IGCC integrated with utility system for CO2 emissions reduction—Simultaneous heat and power generation from IGCC

An integrated gasification combined cycle (IGCC) may be used to generate steam and power while providing a capture-ready CO2 stream. This work addresses techno-economic optimization of an IGCC integrated with the utility system for a process site, with the aim of cost-effective reduction of CO2 emissions. The IGCC can generate power and produce steam in parallel with the site utility system; integration of the IGCC into the site utility system means that the heat recovered from the IGCC is fed to the utility system, where it is used to generate steam to meet site heat and power demand. A relatively rigorous simulation model of the IGCC is applied to explore steam and power generation opportunities for various fuel flow rates. A simple, linear model is regressed from these simulation results to correlate fuel consumption and steam and power generation by the IGCC. The simple model is integrated into a model for simulation and optimization of the site utility system; the operating conditions of the overall system (IGCC and site utility system) can then be optimized to minimize the operating cost, taking into account the capacity and efficiency of equipment such as boilers and steam turbines, the cost of fuel, the cost or value of power, and costs associated with CO2 emissions. The proposed optimization method is illustrated by application to an industrially relevant case study. The results indicate that integrating an IGCC with a site utility system can provide an effective route for cogeneration of heat and power with low carbon emissions and low operating costs, although the economic benefits are sensitive to fuel, power and emissions-related costs.

Thermodynamic performance assessment and comparison of IGCC with solid cycling process for CO2 capture at high and medium temperatures

Solid sorbents can be used to capture CO2 from pre-combustion sources at various temperatures. MgO and CaO are typical medium- and high-temperature CO2 sorbents. However, pure MgO is not active toward CO2. The addition of Na2CO3 increases the operating temperature and significantly increases the reactivity of sorbents to capture CO2. Na2CO3-promoted MgO is a promising medium-temperature CO2 sorbent. In this study, the thermodynamic performance of integrated gasification combined cycle (IGCC) systems with Na2CO3–MgO-based warm gas decarbonation (WGDC) and CaO-based hot gas decarbonation (HGDC) is evaluated and compared with that of an IGCC system with methyldiethanolamine (MDEA)-based cold gas decarbonation (CGDC). Assuming that the average CO2 capture capacities of solid sorbents are one-third of their theoretical maxima, we reveal that the IGCC system undergoes approximately 2.8% and 3.6% improvement on net efficiency when switching from CGDC to WGDC and to HGDC, respectively. The net efficiency of the system is increased by improving the CO2 capture capacity of the sorbent. The IGCC with Na2CO3–MgO experiences more significant increase in efficiency than that with CaO along with the improvement of sorbent average CO2 capture capacity. The efficiency of the IGCC systems reaches the same value when the average CO2 capture capacities of both sorbents are 53% of their theoretical levels. The effects of gas turbine combustor fuel gas inlet temperature on IGCC system performance are analyzed. Results show that the efficiency of the IGCC systems with HGDC and WGDC increases by 0.74% and 0.53% respectively as the fuel gas inlet temperature increases from 250 °C to 650 °C.

Process simulation and thermodynamic analysis of an IGCC (integrated gasification combined cycle) plant with an entrained coal gasifier

An IGCC (integrated gasification combined cycle) is a widely used electrical power generation system that allows for a variety of feedstocks with high efficiencies. In this study, a 300 MW class IGCC plant was simulated using the PRO/II software package, and thermodynamic analysis was performed. The simulated results were compared to the basic design data for a 300 MW Class IGCC demonstration plant to evaluate the validity. Since changing the feed coal grade causes one of the most significant issues in operating an IGCC system, this study investigated the coal sensitivity of the system by examining two different grade coals (Coal #1: 25,439 kJ/kg and Coal #2:21,338 kJ/kg). Their net powers were determined via thermodynamic analysis and by evaluating the power generation and power consumption and were found to be 324.4 MW and 279.1 MW for Coal #1 and Coal #2. Based on the inlet coal energy, the overall efficiencies under the same conditions were found to be 40.38% for Coal #1 and 41.42% for Coal #2. This paper presents Sankey diagrams for the energy and exergy flow associated with the first and second laws of thermodynamics, and discusses how they influence the major components of the IGCC. As a final point, in order to elucidate the preferable coal in terms of financial sense, economic analysis was carried out on the viability of the cases considered. The costs of electricity for Coal #1 and Coal #2 were evaluated as 0.07 US$/kWh and 0.08 US$/kWh. Hence, Coal #1 can confidently be chosen as a more economic option even though, it costs relatively higher than the other Coal #2.

H2/CH4/CO 연료조성 변화에 따른 모형 가스터빈 연소기 불안정 특성에 대한 실험적 연구

IGCC(Integrated Gasification Combined Cycle)의 경우 CCS(Carbon Capture System) 시스템과의 결합을 통하여 지구온난화와 같은 환경문제를 해결할 수 있는 발전 방식의 하나로 여겨진다. 따라서 합성가스 연소특성에 대한 연구가 중요하며 본 연구에서는 <TEX>$H_2/CH_4/CO$</TEX>로 구성된 합성가스 조성을 바꾸어가며 가스터빈 연소불안정 특성에 대한 실험적 연구를 수행하였다. 실험과정에서 발생한 연소불안정에 대한 모드 분석을 수행하였고 연료 중 수소 비율 증가에 따른 주파수 천이 현상 또한 확인하였다. IGCC(Integrated Gasification Combined Cycle) system is candidates which can solve the environmental problems including global warming, since it can be easily combined with CCS(Carbon Capture System). In this research, combustion instability characteristics were studied at various fuel which are composed of <TEX>$H_2/CH_4/CO$</TEX> mixture. Mode analysis for instabilities observed experimentally was conducted and the linearly increasing tendency of frequency was observed as the hydrogen content in fuel increases.

Effect of Additives on the Activity of CuO/Ce0.6Zr0.4O2 Catalysts for the Water‐Gas Shift Reaction

AbstractA series of CuO/Ce0.6Zr0.4O2 catalysts doped with rare earth (Y, La) oxides and transition metal (Fe, Co, Ni) promoters were synthesized by the coprecipitation method. The effects of the additive type and content on the structure, redox properties, and water‐gas shift (WGS) catalytic activity were investigated in detail by X‐ray diffraction, N2 physisorption, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, H2 temperature‐programmed reduction, and Raman spectroscopy. The catalytic activity was tested in terms of CO in H2‐rich coal‐derived synthesis gas, which simulated the actual gas composition of an integrated gasification combined cycle system. The experimental results revealed the beneficial role of doping with 3 wt % Fe in enhancing the catalytic performance by increasing the oxygen storage and mobility capacity, the reducibility, and the synergistic interaction between copper oxide and ceria‐zirconia.

Aspen Plus simulation of biomass integrated gasification combined cycle systems at corn ethanol plants

Biomass integrated gasification combined cycle (BIGCC) systems and natural gas combined cycle (NGCC) systems are employed to provide heat and electricity to a 0.19 hm3 y−1 (50 million gallon per year) corn ethanol plant using different fuels (syrup and corn stover, corn stover alone, and natural gas). Aspen Plus simulations of BIGCC/NGCC systems are performed to study effects of different fuels, gas turbine compression pressure, dryers (steam tube or superheated steam) for biomass fuels and ethanol co-products, and steam tube dryer exhaust treatment methods. The goal is to maximize electricity generation while meeting process heat needs of the plant. At fuel input rates of 110 MW, BIGCC systems with steam tube dryers provide 20–25 MW of power to the grid with system thermal efficiencies (net power generated plus process heat rate divided by fuel input rate) of 69–74%. NGCC systems with steam tube dryers provide 26–30 MW of power to the grid with system thermal efficiencies of 74–78%. BIGCC systems with superheated steam dryers provide 20–22 MW of power to the grid with system thermal efficiencies of 53–56%. The life-cycle greenhouse gas (GHG) emission reduction for conventional corn ethanol compared to gasoline is 39% for process heat with natural gas (grid electricity), 117% for BIGCC with syrup and corn stover fuel, 124% for BIGCC with corn stover fuel, and 93% for NGCC with natural gas fuel. These GHG emission estimates do not include indirect land use change effects.

Techno-Economic Analysis of the Use of Fired Cogeneration Systems Based on Sugar Cane Bagasse in South Eastern and Mid-Western Regions of Mexico

In this paper two cogeneration systems (Biomass steam turbines and biomass gasification combined cycle) were evaluated and compared based on their potential to meet heat and power requirements of sugar/alcohol plants in two regions of Mexico (south eastern and mid western), which are both characterized by higher production rates of sugar cane. In addition, the potential of those systems to produce an electricity surplus was evaluated as a means to generate additional income in terms of co-product credit. The latter was evaluated in order to reduce the total production cost of fuel ethanol and identify a potential electricity surplus for use by local inhabitants. The analysis was performed comparing different scenarios based on the use of the current planted area in these regions to produce ethanol. Biomass integrated gasification combined cycle system was proven as the most advantageous system to meet heating requirements, generating an important amount of electricity with contribution of about 18 % in reduction of the total production cost of ethanol. Moreover, results indicate the potential to strengthen relations between the two regions with higher opportunities to increase incomes, as well as the improvement of added value cane bagasse with off-season electricity generation.

Efficiency of wet feed IGCC (integrated gasification combined cycle) systems with coal–water slurry preheating vaporization technology

Coal–water slurry (CWS) preheating vaporization technology is an important new technology for the future development of Integrated Gasification Combined Cycle (IGCC) systems, providing an opportunity to improve the energy efficiency of wet feed gasification processes. This manuscript systematically analyzed the influence of integration of this technology on the energy efficiency performance of wet feed IGCC systems with or without carbon capture. We designed, simulated and compared ten cases of IGCC systems, including three wet feed IGCC systems with distinct integration modes for CWS preheating technology, one traditional wet feed IGCC and one dry feed IGCC as reference cases, all of which have one case with carbon capture and another case without carbon capture. The results indicate that, without carbon capture, the overall energy efficiencies of wet feed IGCC systems integrated with this technology are 1–5 percentage points (1%–5%) higher than that of the original wet feed IGCC system, depending on the integration mode. When carbon capture is introduced, the overall energy efficiencies of wet feed IGCC systems integrated with this technology are close to or even higher than that of the dry feed IGCC system.

Computational Fluid Dynamic Modeling of Entrained-Flow Gasifiers with Improved Physical and Chemical Submodels

Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. While the Lagrangian discrete phase formulati...

Proposed combined-cycle power system based on oxygen-blown coal partial gasification

A combined-cycle power system based on oxygen-blown coal partial gasification is proposed to promote the performance and reduce the investment of conventional integrated gasification combined cycle (IGCC) power system. The proposed power system combines the characteristics of IGCC and pressurized fluidized-bed cycle power systems, and its performance is analyzed. The thermal efficiency of the proposed power system is about 3% higher than that of the reference system. Exergy analysis is also performed to reveal the internal phenomenon of the energy conversion. It is found that the main character of the proposed power system is the reduction of exergy destruction during chemical energy conversion processes, i.e., the gasification process and the syngas combustion process. Such a result implies the proposed power system can realize better utilization of the coal chemical energy. Some other configurations of the proposed power system are also considered for varying the work conditions or for further adaptation to state-of-the-art technology. The primary investment cost of the proposed power system is also reduced due to the decrease in the gasification temperature and the carbon conversion ratio.

Effect of zirconium addition on the structure and properties of CuO/CeO2 catalysts for high-temperature water–gas shift in an IGCC system

A series of CexZr1-xO2-based Cu catalysts was synthesized by the co-precipitation method. The influences of copper content, zirconium addition, and ratio of ceria to zirconia on the catalytic activity were investigated. BET, N2O decomposition, XRD, TEM, SEM, EDS, Raman spectroscopy, H-2-TPR, TG/DTA, and XPS were used to characterize the catalysts. The catalytic activity was tested in terms of CO conversion and H-2 selectivity in H-2-rich coal-derived synthesis gas, simulating the actual gas composition of an integrated gasification combined cycle (IGCC) system. The long-term catalyst stability was also examined at 450 degrees C for 196 h. The addition of zirconium was found to be very important in enhancing catalytic performance. The surface area, copper dispersion, oxygen storage and mobility capacity, reducibility, as well as resistance to sintering all improved after zirconium addition. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

CO2 absorption characteristics of nanoparticle suspensions in methanol

Recently there have been growing concerns that anthropogenic carbon dioxide (CO2) emissions cause the global warming problem. Therefore, the cutting-edge technologies for the reduction, separation and collection of the CO2 are very important to alleviate this problem. The best methods for reducing the CO2 emission are to increase the energy efficiency and to remove it from the power plant. The CO2 absorption from the syngas in the integrated gasification combined cycle (IGCC) might increase the energy efficiency of the power generation systems, which also contribute to mitigate the global warming. In this study, the suspensions of nanoparticles in methanol (called the nanofluid) are developed and estimated to apply it to absorb CO2 gas in the IGCC systems. The nanofluids are prepared by the ultrasonic treatment and show the good stability. It is found that the CO2 absorption rate by the nanofluid is enhanced up to ∼8.3% compared to the pure methanol.

The development situation of biomass gasification power generation in China

This work presents the development situation of biomass gasification power generation technology in China and analyzes the difficulty and challenge in the development process. For China, a large agricultural country with abundant biomass resources, the utilization of biomass gasification power generation technology is of special importance, because it can contribute to the electricity structure diversification under the present coal-dominant electricity structure, ameliorate the environmental impact, provide energy to electricity-scarce regions and solve the problems facing agriculture. Up to now, China has developed biomass gasification power generation plants of different types and scales, including simple gas engine-based power generation systems with capacity from several kW to 3MW and integrated gasification combined cycle systems with capacity of more than 5MW. In recent years, due to the rising cost of biomass material, transportation, manpower, etc., the final cost of biomass power generation has increased greatly, resulting in a serious challenge in the Chinese electricity market even under present preferential policy for biomass power price. However, biomass gasification power generation technology is generally in accord with the characteristics of biomass resources in China, has relatively good adaptability and viability, and so has good prospect in China in the future.

IGCC 플랜트에서 산소공급방식이 성능에 미치는 영향

In this paper, two types of integrated gasification combined cycle (IGCC) plants using either an air separation unit (ASU) or an ion transport membrane (ITM), which provide the oxygen required in the gasification process, were simulated and their thermodynamic performance was compared. Also, the influence of adopting a pre-combustion <TEX>$CO_2$</TEX> capture in the downstream of the gasification process on the performance of the two systems was examined. The system using the ITM exhibits greater net power output than the system using the ASU. However, its net plant efficiency is slightly lower because of the additional fuel consumption required to operate the ITM at an appropriate operating temperature. This efficiency comparison is based on the assumption of a moderately high purity (95%) of the oxygen generated from the ASU. However, if the oxygen purity of the ASU is to be comparable to that of the ITM, which is over 99%, the ASU based IGCC system would exhibit a lower net efficiency than the ITM based system.

A Method for Screening the Potential of MOFs as CO2 Adsorbents in Pressure Swing Adsorption Processes

This work reports the adsorption and coadsorption data of CO(2)/CH(4)/CO mixtures on several metal-organic frameworks [MOFs; MIL-100(Cr), MIL-47(V), MIL-140(Zr)-A, Cu-btc, and MIL-53(Cr)] and compares them with reference adsorbents, that is, zeolite NaX and an activated carbon material, AC35. We also evaluate the effect of H(2)O on CO(2) adsorption and on the stability of the structures. Based on the experimental adsorption data, the performance potential of MOFs in several pressure swing adsorption processes is estimated by making a ranking of working capacities and separation factors. We discuss the separation of biogas, the purification of H(2) produced by steam reforming of methane, and the removal of CO(2) from synthesis gas in IGCC (integrated gasification combined cycle) systems. Some MOFs are very well placed in the ranking of (isothermal) working capacity vs. selectivity. Yet, performance is not the only criterion for the selection of MOFs. Ease and cost of synthesis and long-term stability are other important aspects that have to be taken into account.

Modeling and analysis of selected carbon dioxide capture methods in IGCC systems

Carbon dioxide capture from energy systems will likely become a necessity as the European Union regulations are becoming increasingly more stringent. The greatest disadvantage of the existing methods of CO2 separation is the high energy intensity. In the Integrated Gasification Combined Cycle (IGCC) system, the carbon dioxide capture process is conducted before combustion, which facilitates the separation. In this paper, two methods of CO2 capture are compared. The first is the most frequently considered, known as chemical absorption. The second is membrane CO2 separation, which is not as commonly deployed but has the potential to be an even more efficient process.The models of CO2 capture installations were built in Aspen software. The two processes used in the analyses were primarily compared with respect to the energy intensity of each method. The results of the analysis show that the use of membranes allows for a significant decrease in the energy intensity of the capture process compared with the absorption process. However, the purity of the separated CO2 significantly depends on the type and surface of the membrane and on the process parameters. Nevertheless, it is clear that the development of membrane techniques will enable the most competitive CO2 capture solutions, in terms of effectiveness and cost, compared with other methods.