Advanced Integrated Gasification Combined Cycle Research Articles

An evaluation of advanced combined cycles

The main objective of this investigation is to identify and assess advanced improvements to the combined cycle such as gas turbine firing temperature, pressure ratio, combustion techniques, intercooling, enhanced blade cooling schemes and supercritical steam cycles that will lead to significant performance improvements in coal based power systems. This assessment is conducted in the context of conceptual designs that advance state-of-art combined cycles and result in an 8% reduction in heat rate over a coal based Integrated Gasification Combined Cycle (IGCC) plant utilizing an H class gas turbine technology with steam cooling. This efficiency goal for the study was set by the United States Department of Energy. H class gas turbines are commercially offered by General Electric (GE), Mitsubishi and Siemens for natural gas based combined cycle applications with 60% efficiency (LHV) and it is expected that such machines will be offered for syngas applications within the next 5–10years, while our investigation looks further beyond that time frame. The levelized cost of electricity for an IGCC utilizing the H class gas turbine is $86/MWh while that for the advanced IGCC identified in this investigation consisting of an intercooled gas turbine with a firing temperature that is 340°C higher is $79/MWh which is a significant 8% reduction.

A thermodynamic study of the removal of HCl and H2S from syngas

Advanced integrated-gasification combinedcycle (IGCC) and integrated-gasification fuel cell (IFGC) systems require high-temperature sorbents that are capable of removing hydrogen chloride and hydrogen sulfide from coal derived gases to very low levels. HCl and H2S are highly reactive, corrosive, and toxic gases that must be removed to meet stringent environmental regulations, to protect power generation equipment and to control the emissions of contaminants. The thermodynamic behavior of 13 sorbents for the removal of HCl and H2S under various conditions including: initial toxic gas concentration (1–10000 ppm), operating pressure (0.1–11 Mpa), temperature (300 K–1500 K), and the presence of H2O were investigated. The correlation between HCl and H2S was also examined. Thermodynamic calculations were carried out for the reactions of the 13 sorbents using a FactSage 5.2 software package based on free energy minimization. The sorbents, Na2CO3, NaHCO3, K2CO3, and CaO are capable of completely removing chlorine at high temperatures (up to ∼1240 K) and at high pressures. Water vapor did not have any significant effects on the dechlorination capability of the sorbents. Nine of the sorbents namely; Cu2O, Na2CO3, NaHCO3, K2CO3, CaO, ZnO, MnO, FeO, and PbO, were determined to have great potential as desulfurization sorbents. Cu2O and ZnO had the best performance in terms of the optimum operating temperature. The addition of water vapor to the reactant gas produces a slightly detrimental effect on most of the sorbents, but FeO exhibited the worst performance with a reduction in the maximum operating temperature of about 428 K. The dechlorination performance of the alkali sorbents was not affected by the presence of H2S in the reactions. However, the desulfurization capability of some sorbents was greatly affected by the presence of HCl. Particularly, the performance of Cu2O was significantly reduced when HCl was present, but the performance of FeO improved remarkably. The thermodynamic results gathered are valuable for the developments of better sorbents.

Congress examines administration's coal research priorities

While the Obama administration has proposed a shift in coal research funding to further emphasize carbon capture and sequestration (CCS) programs in its fiscal year (FY) 2012 budget request, Republicans and several witnesses at a 13 October hearing of a subcommittee of the House of Representatives' Committee on Science, Space, and Technology questioned those priorities, called for additional federal funding for coal research, and defended the use of coal as a major part of the U.S. energy sector. The administration's FY 2012 budget requests $291.4 million to fund the Department of Energy's (DOE) CCS and power systems program while zeroing out funding for DOE's fuels and power systems program (which includes funding for coal research) and shifting some of its line items to the CCS program. The FY 2011 continuing resolution has funded the fuels and power systems program at $400.2 million, including $142 million for carbon sequestration, $64.8 million for innovations for existing plants, and funding for other subprograms such as advanced integrated gasification combined cycle ($52.9 million), fuel cells ($49.8 million), and advanced research ($47.6 million).

Thermodynamic Analysis and Optimization of IT-SOFC-Based Integrated Coal Gasification Fuel Cell Power Plants

This work discusses the thermodynamic analysis of integrated gasification fuel cell plants, where a simple cycle gas turbine works in a hybrid cycle with a pressurized intermediate temperature–solid oxide fuel cell (SOFC), integrated with a coal gasification and syngas cleanup island and a bottoming steam cycle (reflecting the arrangement of integrated gasification combined cycle (IGCC) plants) to optimize heat recovery and maximize efficiency. This work addresses the optimization of the plant layout, discussing the effect of the SOFC fuel utilization factor and the possibility of a fuel bypass to increase the gas turbine total inlet temperature and reduce the plant expected investment costs. Moreover, a discussion of technological issues related to the feasibility of the connection among the plant high temperature components is carried out, presenting the effects of different limitations of the maximum temperatures reached by the plant piping. With the proposed plant configurations, which do not include—apart from the SOFC—any component far from the nowadays best available technologies, a net electric lower heating value efficiency approaching 52–54% was calculated, showing a remarkable increase with respect to state-of-the-art advanced IGCCs.

High-density circulating fluidized bed gasifier for advanced IGCC/IGFC—Advantages and challenges

Coal-fired Integrated Gasification Combined Cycle (IGCC) and Integrated coal Gasification Fuel-cell Combined cycle (IGFC) are being developed as high-efficiency electric power generation technology. However, the highest theoretical gross thermal efficiency of the conventional IGCC/IGFC is still below 52%. In order to obtain higher power generation efficiency, an advanced IGCC (A-IGCC) or advanced IGFC (A-IGFC) system making use of the exergy recuperation concept by recycling waste heat from gas turbine or fuel cells for steam gasification of coal and biomass was proposed in our laboratory. Corresponding to this system, a novel high-density triple-bed combined circulating fluidized bed (TBCFB) gasifier, composed of a downer pyrolyzer, a bubbling fluidized bed char gasifier, and a riser combustor, was proposed to replace traditional gasifiers such as the entrained flow bed gasifier. The new system is expected to more effectively utilize the waste heat from gas turbines or fuel cells and the heat produced by the combustion of the unreacted char in the riser combustor for pyrolysis and gasification of coal and biomass. In this short review, the advantages and future challenges in the development of high-density TBCFB gasifier are presented and discussed.

가스화 복합화력발전 플랜트에서 CO2제거가 성능에 미치는 영향 해석

In the power generation industry, various efforts are needed to cope with tightening regulation on carbon dioxide emission. Integrated gasification combined cycle (IGCC) is a relatively environmentally friendly power generation method using coal. Moreover, pre-combustion capture is possible in the IGCC system. Therefore, much effort is being made to develop advanced IGCC systems. However, removal of prior to the gas turbine may affect the system performance and operation because the fuel flow, which is supplied to the gas turbine, is reduced in comparison with normal IGCC plants. This study predicts, through a parametric analysis, system performances of both an IGCC plant using normal syngas and a plant with capture. Performance characteristics are compared and influence of capture is discussed. By removing from the syngas, the heating value of the fuel increases, and thus the required fuel flow to the gas turbine is reduced. The resulting reduction in turbine flow lowers the compressor pressure ratio, which alleviates the compressor surge problem. The performance of the bottoming cycle is not influenced much.

Long-term coal gasification-based power with near-zero emissions. Part B: Zecomag and oxy-fuel IGCC cycles

In this second part of the work, two other long-term technologies for power generation from coal are investigated. The Zecomag plant has the same syngas production system of the Zecomix plant, described in the first part of this paper, but hydrogen-rich syngas is here burned with air in an open-cycle gas turbine. The aim is a simplification of the power island, more similar to a combined cycle; however, CO 2 capture falls from 100% to about 90% and NO x emissions are present. An advanced oxy-fuel IGCC is the second plant investigated in this paper, presenting the same zero-emission potential of Zecomix. Syngas is produced in a high pressure, dry feed, oxygen blown gasifier and cleaned in a hot-gas-clean-up system. Clean syngas is then burned with oxygen and expanded in a turbine, using compressed recirculated CO 2 to moderate firing temperature and to cool turbine blades. The loss of net efficiency, with respect to Zecomix, is very limited (1–2 points) with both configurations. In order to better evaluate the performances obtained, a comparison with reference state-of-the art IGCCs and a long-term IGCC without CO 2 capture is also presented.

Techno-economic evaluation of advanced IGCC lignite coal fuelled power plants with CO 2 capture

The techno-economic evaluation of four novel integrated gasification combined cycle (IGCC) power plants fuelled with low rank lignite coal with CO 2 capture facility has been investigated using ECLIPSE process simulator. The performance of the proposed plants was compared with two conventional IGCC plants with and without CO 2 capture. The proposed plants include an advanced CO 2 capturing process based on the Absorption Enhanced Reforming (AER) reaction and the regeneration of sorbent materials avoiding the need for sulphur removal component, shift reactor and/or a high temperature gas cleaning process. The results show that the proposed CO 2 capture plants efficiencies were 18.5–21% higher than the conventional IGCC CO 2 capture plant. For the proposed plants, the CO 2 capture efficiencies were found to be within 95.8–97%. The CO 2 capture efficiency for the conventional IGCC plant was 87.7%. The specific investment costs for the proposed plants were between 1207 and 1479 €/kW e and 1620 €/kW e and 1134 €/kW e for the conventional plants with and without CO 2 capture respectively. Overall the proposed IGCC plants are cleaner, more efficient and produce electricity at cheaper price than the conventional IGCC process.

Comparison of reduction behavior of Fe 2O 3, ZnO and ZnFe 2O 4 by TPR technique

Advanced integrated gasification combined cycle (IGCC) power generation systems require the development of high-temperature, regenerable, desulfurization sorbents capable of removing hydrogen sulfide from coal gasifier gas to very low levels. As a sort of effective desufurizer, such as Fe 2O 3, ZnO and ZnFe 2O 4, it will endure strong reducing atmosphere in desulfurization process. The reduced degree of desufurizer can have an effect on its desulfurization reactivity. In this paper, Fe 2O 3, ZnO and ZnFe 2O 4 were synthesized by precipitation or co-precipitation at constant pH. After aging, washing and drying, the solids were calcined at 800 °C. The reduction behaviors of sample were characterized by temperature-programmed reduction (TPR). It is found that there are two reduction peaks for Fe 2O 3 in TPR, and whereas no reduction peaks for ZnO are found. The reduction process of ZnFe 2O 4 prepared by co-precipitation is different from that of Fe 2O 3. ZnFe 2O 4 is easier to be reduced than Fe 2O 3. The activation energy of reduction process for Fe 2O 3 and ZnFe 2O 4 is obtained at different reduction periods.

Simulation of a Process to Capture CO2 From IGCC Syngas Using a High Temperature PBI Membrane

Abstract Capture of carbon dioxide from an advanced integrated gasification combined-cycle (IGCC) process offers several technical and economic advantages over the conventional coal-combustion systems. The pre-combustion gas stream is at high pressure, has low volumetric flow rates and is capable of producing relatively pure hydrogen for conversion into electricity by gas turbines or fuel cells without generating additional carbon dioxide. Polybenzimidazole (PBI) polymer shows promise as a high temperature membrane material for pre-combustion-based capture of CO2 from IGCC gas streams. We are developing a process that is based on PBI membrane to achieve a capture of 90% CO2 as a high pressure stream with about 10% increase in the cost of energy. A significant advantage of the PBI membrane compared to other sorbent-based technologies and conventional polymeric membranes is that PBI membrane is capable of operating at over a broader temperature range (∼100–400 ∘C). In contrast, solvent-based processes such as Selexol require syngas cooling prior to treatment, followed by reheating the processed fuel gas stream. In this paper, we are presenting the preliminary results of a process simulation using the ASPEN program under several scenerios including the IGCC with no CO2 capture, IGCC with Selexol, and IGCC with PBI membrane separator. The high temperature membrane-based CO2 capture method compares favorably against the Selexol-based CO2 capture method. If H2S remains with the CO2 stream and can be sequestered, then the cost of electricity appears to be lower than Selexol-bsed separation systems.

Bench-Scale Testing of Zinc Ferrite Sorbent for Hot Gas Clean-up

Abstract Advanced integrated gasification combined cycle (IGCC) power generation systems require the development of high-temperature, regenerable desulfurization sorbents, which are capable of removing hydrogen sulfide from coal gasifier gas to very low levels. In this paper, zinc ferrites prepared by co-precipitation were identified as a novel coal gas desulfurization sorbent at high temperature. Preparation of zinc ferrite and effects of binders on pore volume, strength and desulfurization efficiency of zinc ferrite desulfurizer were studied. Moreover, the behavior of zinc ferrite sorbent during desulfurization and regeneration under the temperature range of 350-400 °C are investigated. Effects of binders on the pore volume, mechanical strength and desulfurization efficiency of zinc ferrite sorbents indicated that the addition of kaolinite to zinc ferrite desulfurizer seems to be superior to other binders under the experimental conditions.

CO 2 capture study in advanced integrated gasification combined cycle

This paper presents the results of technical and economic studies in order to evaluate, in the French context, the future production cost of electricity from IGCC coal power plants with CO 2 capture and the resulting cost per tonne of CO 2 avoided. The economic evaluation shows that the total cost of base load electricity produced in France by coal IGCC power plants with CO 2 capture could be increased by 39% for ‘classical’ IGCC and 28% for ‘advanced’ IGCC. The cost per tonne of avoided CO 2 is lower by 18% in ‘advanced’ IGCC relatively to ‘classical’ IGCC. The approach aimed to be as realistic as possible for the evaluation of the energy penalty due to the integration of CO 2 capture in IGCC power plants. Concerning the CO 2 capture, six physical and chemical absorption processes were modeled with the Aspen Plus™ software. After a selection based on energy performance three processes were selected and studied in detail: two physical processes based on methanol and Selexol™ solvents, and a chemical process using activated MDEA. For ‘advanced’ IGCC operating at high-pressure, only one physical process is assessed: methanol.

Hot gas cleanup: pilot testing of moving bed filters

In recent issues of the magazine, J Smid, SS Hsiau, CY Peng and HT Lee have assessed granular moving bed hot gas particulate clean up systems for advanced IGCC and PFBC power stations; looked at the development of particulate collection devices; as well as highlighting new designs of moving bed filters. In the final part, they examine filter media and moving bed filter pilot plants.

Hot gas cleanup: new designs for moving bed filters

In recent issues of the magazine, J Smid, SS Hsiau, CY Peng and HT Lee have assessed granular moving bed hot gas particulate clean up systems for advanced IGCC and PFBC advanced power stations (under development in the USA), as well as the development of particulate collection devices themselves. They now look at some new designs of moving bed filters…

Moving bed filters for hot gas cleanup

In the December issue of Filtration+Separation, J Smid, S.S Hsiau, CY Peng and HT Lee assessed granular moving bed hot gas particulate clean up systems for advanced IGCC and PFBC advanced power stations, under development in the USA. They now turn their attention to the development of the particulate collection devices themselves…

Hot gas granular moving bed filters for advanced power systems

In advanced coal-fire cycles it is important to remove the fine particles from high temperature and high pressure gas streams, to satisfy gas turbine fuel quality requirements. J Smid, S S Hsiau, C Y Peng and H T Lee assess granular moving bed hot gas particulate clean-up systems for advanced IGCC and PFBC, under development in the USA.

Integrated protein production and electricity generation using renewable alfalfa feedstock in a combination advanced IGCC and feed processing arrangement

Integrated protein production and electricity generation using renewable alfalfa feedstock in a combination advanced IGCC and feed processing arrangement

Concept for a competitive coal fired integrated gasification combined cycle power plant

The design efficiency for a state-of-the-art supercritical coal fired pulverised fuel (p.f.) power plant (e.g. Nordjyllandsvaerket) is quoted at 47%, compared to 43% for the most advanced existing coal-based integrated gasification combined cycle (IGCC) plants (e.g. Buggenum and Puertollano). Of course, power plant design engineers have the experience of thousands of p.f. plants to guide them, compared with a mere handful of IGCC plants. There are also climatic and feedstock reasons why the above comparison is not a fair one. However, there is no doubt that for the environmentally friendly IGCC plants to penetrate the coal based power generation market it is necessary to demonstrate improved efficiency, reduced costs and increased availability.A number of techno-economic studies have been undertaken to see what is possible for IGCC, starting from the situation at Puertollano in Spain. These studies firstly remove the differences caused by the feedstock and the climatic conditions and then go on to look at an advanced IGCC concept that has been developed based on materials, components and processes that are available now. With the advanced IGCC concept it has been shown that the efficiency can be improved to over 50%, with an investment of less than ▪1000/kWe. Future development work on IGCC would be more profitably directed towards reducing capital costs and improving occupancy rather than efficiency improvements.

99/01176 A new approach for IGCC process synthesis under uncertainty : Rubin, E. S. and Diwekar, U. M. EC(Am. Soc. Mechanical Eng.), 1997, 5, 1–7

99/01176 A new approach for IGCC process synthesis under uncertainty : Rubin, E. S. and Diwekar, U. M. EC(Am. Soc. Mechanical Eng.), 1997, 5, 1–7

97/05071 Development of advanced sorbents for hot gas desulfurization: Abbasian, J. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1996, 13, (1), 602–607

Integrated Gasification Combined-Cycle (IGCC) processes are among the leading contenders for the production of electricity from coal. Coal gas desulfurization to sufficiently low levels at elevated temperatures (T > 350 C) is now recognized as crucial to efficient and economic coal utilization in advanced IGCC processes. The implementation of hot coal gas desulfurization relies heavily on the development of regenerable sorbent materials which can efficiently reduce H{sub 2}S from several thousand ppmv levels down to a few ppmv over many cycles of sulfidation/regeneration. Zinc-based sorbents, such as zinc titanate, are currently the leading candidate sorbents, however, they have been shown to suffer from zinc volatilization at elevated temperatures leading to sorbent deterioration, increasing sorbent replacement costs, and the overall cost of hot gas cleanup. This paper discusses the results obtained in an ongoing investigation geared towards developing advanced mixed-metal oxide sorbents for desulfurization of coal-derived fuel gases in the temperature range of 350 to 550 C. The paper focuses on the study related to the development of durable sorbents and addresses thermodynamic considerations, sulfidation kinetics, regenerability, and long term durability of a number of novel sorbents.