Integrated Gasification Combined Cycle Plant Research Articles

Life cycle meta-analysis of carbon capture pathways in power plants: Implications for bioenergy with carbon capture and storage

Bioenergy with carbon capture and storage (BECCS) based electricity generation is one possible approach for delivering large-scale carbon dioxide removal from the atmosphere. This study evaluates the environmental impacts of leveraging existing power plants for BECCS. We performed a life cycle meta-analysis of eight carbon capture technologies, including five previously simulated only for coal and natural gas, for both steam cycle and integrated gasification combined cycle (IGCC) power plants. We found that IGCC plants offer the best balance of negative emissions, energy return on investment (EROI) and low water use irrespective of capture technologies. Planned IGCC plants tend to be large whereas biomass-fired power plants are often small and distributed in the landscape because of the distributed nature of the fuel. Steam cycle plants had larger negative emissions, but also lower EROI, and so blending with coal may be necessary to achieve a suitable EROI. Steam cycles were sensitive to capture technology type, and results found membrane and calcium looping capture technologies offer a balance between negative emissions, EROI and water use when fired using coal-biomass blends. These results suggest that steam cycle power plants may be the most desirable candidates to support early-stage deployment of BECCS.

Coal Gasification: At the Crossroad. Technological Factors

The article presents results from analyzing the state of the art achieved in the coal gasification technologies developed around the world and the demand for them. It is shown that such technologies have presently arrived at a crossroad in their development. Their future will be determined by the development prospects of coal energy as a whole. Coal still continues to play the most important role in the world energy. In recent years, external factors have become extremely negative for the development of coal energy. Among other fuels, coal produces the largest specific emissions of CO2 during its combustion, in view of which it may become the first victim of the unfolding energy decarbonization policy. Under such conditions, there is a need to diversify the coal utilization fields, primarily through manufacturing a wide range of chemical products with a high added value. This generates the need to develop the appropriate technologies, and, first of all, gasification technologies, the use of which opens the possibility of making almost the entire range of products from coal that are obtained from petroleum and natural gas. It has been determined that gasification technologies have already reached a high level of technical maturity, and a large number of gasifier designs have been proposed. It has been determined that the majority of operating coal gasification plants are presently used for manufacturing various chemical products, first of all, natural gas substitute (which is then forwarded to gas networks) and also methanol and ammonia. It is pointed out that only a few integrated gasification combined cycle plants have been implemented and planned for construction, which means that the private sector shows little interest in this technology. At the same time, such plants have quite a high potential for being used in low-carbon energy, of course, provided that the problem of disposing the captured CO2 is solved. It is shown that a large number of gasifier equipment manufacturers are available around the world. However, gasifiers are produced in single units or in a small series, which unavoidably leads to the high cost of this equipment. For the further innovative development of the gasification technology, combined efforts should be taken by the private sector and the state.

Technical and economical evaluation of a high-temperature air heater intended for integrated gasification combined cycle unit

In this paper the costs of creating a high-temperature air heater intended for the integrated gasification combined cycle unit developed by the authors are estimated and are compared with a steam boiler. The results can be used not only in the further development of the integrated gasification combined cycle plant under consideration, but also be interesting to specialists involved in the development of various high-temperature heat exchangers.

Prospect of near-zero-emission IGCC power plants to decarbonize coal-fired power generation in China: Implications from the GreenGen project

An integrated gasification combined cycle (IGCC) power plant with pre-combustion CO2 capture provides a solution to achieve energy security with CO2 emission reduction in China, which has a coal-dominant energy resource structure. This study utilizes the electricity generation and cost information of the GreenGen IGCC plant (265 MW), which is the first and, to date, the only IGCC facility in China, to evaluate the economic performance and competitiveness of this emerging clean coal technology. In the construction stage, the initial investment on the GreenGen plant was approximately $565 million (capital cost: 2133 $/kW; in constant 2017 US dollars). Compared with the US, China incurred significantly lower costs of initial investment for the construction of the IGCC plant, owing to the adoption of a self-developed gasifier. During the operation stage, the levelized cost of electricity (LCOE) without CO2 capture for the GreenGen plant was calculated as 103 $/MWh, whereas it increased to 131 $/MWh with pre-combustion CO2 capture (CO2 capture cost: 42 $/tonne). Currently, an IGCC plant with integrated CO2 capture remains too expensive to be widely used in China. However, simulation results indicate that the LCOE of China’s IGCC plants could be potentially reduced to 80 $/MWh in the future owing to technology innovation, large-scale application and cumulative production. Government policy and financial support to stimulate the research and development of gas turbine and low-rank coal gasification technologies and to subsidize the operation of IGCC plants owing to their environmental benefits would play critical roles in accelerating the development of near-zero-emission IGCC power plants in China.

Selecting the design of a high-temperature air heater for integrated gasification combined cycle

High temperature heat exchangers are needed in various energy technologies to increase their efficiency. The article is devoted to the optimization of the design of a high-temperature air heater used in the integrated gasification combined cycle plant, developed in Ural Federal University. In the air heater, air with a pressure of 2 MPa after the cycle compressor is heated by coal combustion to a temperature of 900°C before it is fed into the combustion chamber of a gas turbine. The air heater is developed as a pulverized coal fired boiler with air heating in tubular radiation-convection heating surfaces. The authors propose a new design of a high-temperature air heater, which allows reducing the cost of the expensive high-temperature part of the unit 1.8 times compared with the previous design. A computer simulation of the boiler section is carried out to verify the proposed design solutions.

Conventional and advanced exergy, exergoeconomic and exergoenvironmental analysis of a biomass integrated gasification combined cycle plant

ABSTRACTBiomass gasification for the production of clean energy and clean technology is a practical alternative to fossil fuels. In this paper, for the first time, a biomass Integrated Gasification Combined Cycle (IGCC) based on olive pits as fuel is investigated by conventional and advanced exergy, exergoeconomic and exergoenvironmental analyses (4E). Environmental impacts, availability, and interest in using olive pits as newly utilized renewable biomass sources have been considered in the present study. With conventional exergy analysis, the primary causes of entropy generation, exergy cost of destruction, and exergoenvironmental impacts in the plant can be indicated. Also, with advanced analysis, the real potential can be determined for improving the system as well as equipment interactions. The exerg environmental analysis has been performed based on Life Cycle Assessment and Eco indicator 99. In this regard, the LCA analysis based on Eco indicator 99 has been done by SIMA Pro software. Furthermore, computer code has been developed for thermodynamic simulation and conventional and advanced 4E analyses of the proposed system. It can predict the plant behavior for different operating conditions with relative errors of less than 2.5% with Thermoflex software. Results show the conventional and advanced 4E analyses and evaluation for considered biomass IGCC systems simultaneously. By the exergetic analysis, the location, values, and sources of entropy generation in the system are identified. By exergoeconomic analysis, the information about the cost in the components has been indicated in terms not only of capital investment but also of the cost of exergy. Through the exergoenvironmental analyses, it can be concluded that improving the efficiency and decreasing fossil fuel consumption are the key factors of promoting environmental characteristics. Splitting the exergy destruction, the capital investment cost, and the component-related environmental impact related to each component into endogenous/exogenous and avoidable/unavoidable parts promotes these analyses and enhances the quality of the conclusions achieved from them.

Supply smoothing planning with integrated gasification combined cycle to address renewable fluctuations in small-scale grids

Integrated gasification combined cycle (IGCC) technology is an efficient way to reduce CO2 emissions from fossil fuels, achieving lower emissions than liquid natural gas combined cycle (LNG-CC) plants. In this study, we examine the performance of an IGCC plant for smoothing network-frequency deviations in a stand-alone power-supply network with fluctuating renewable generation by developing a numerical model of the plant’s dynamic response to realistic load changes with meteorological conditions. The IGCC plant with added inertia from a flywheel is very effective for accommodating short-cycle fluctuations associated with photovoltaic generation, but it performs poorly with the long-cycle fluctuations associated with wind generation. The same numerical analysis was used to compare IGCC and LNG-CC plants in equal terms. The LNG-CC plant’s faster load response is more suited for interconnection with windfarms, although the IGCC emits about half as much CO2. Both technologies may prove useful for installation along with renewable generation capacity.

Co-optimization of thermal power plant flowchart, thermodynamic cycle parameters, and design parameters of components

The improvement in the efficiency of an energy plant depends on a rational development of its flowchart and choice of parameters along with the load schedule, equipment reliability, operating mode, etc. It is advisable to study such complex technical systems with the methods of mathematical modeling and optimization. The paper presents an approach to the development of optimal flowcharts and selection of parameters of energy plants. The approach is based on the combination of a method for optimization of the most complex flowchart and a method for solving discrete-continuous problems of nonlinear mathematical programming. A case study of the co-optimization of design parameters, operating parameters and equipment mix for the integrated gasification combined-cycle plant is demonstrated. The optimization calculations were carried out by the criterion of the minimum price of electricity for a given internal rate of return on investment and the maximum energy efficiency of the plant. Several optimal solutions meeting the different criteria are obtained. The proposed approach can be used for optimization of flowcharts and parameters of other complicated energy plants (high-efficiency combined-cycle plants, ultra-supercritical steam cycles, integrated power plants for electricity and synthetic liquid fuel co-production from coal, etc.).

The oxygen production pre-combustion (OPPC) IGCC plant for efficient power production with CO2 capture

This work presents a novel integrated gasification combined cycle (IGCC) power plant configuration for CO2 capture with minimal energy penalty. The proposed oxygen production pre-combustion (OPPC) power plant synergistically integrates a gas switching oxygen production (GSOP) unit into a pre-combustion IGCC power plant, reducing the energy penalty through two channels: 1) avoidance of a cryogenic air separation unit and 2) pre-heating the air sent to the combined power cycle, which reduces the steam requirement for shifting CO to H2 and the CO2 capture duty involved in pre-combustion CO2 capture. Relative to a conventional pre-combustion IGCC benchmark, the OPPC configuration improves the electric efficiency by about 6%-points, although the CO2 capture ratio reduces by about 6%-points. OPPC as avoids the maximum temperature limitation of Chemical Looping Combustion based plants, and can therefore benefit from efficient modern gas turbine technology operating at very high inlet temperatures. CO2 removal via physical absorption (Selexol) generally results in higher efficiencies, but lower CO2 avoidance than chemical absorption (MDEA). Plant efficiency also benefits from an increase in GSOP operating temperature, although the maximum temperature was limited to 900 °C to avoid any temperature-related challenges with oxygen carrier stability or downstream valves and filters. OPPC therefore appears to be a promising configuration for minimizing the energy penalty of CO2 capture in IGCC power plants, combining well known and proven technology blocks with a GSOP reactor cluster instead of an ASU.

Techno-economic analysis of the effects of heat integration and different carbon capture technologies on the performance of coal-based IGCC power plants

Coal-based Integrated Gasification Combined Cycle (IGCC) power plants show obvious gains over conventional pulverized coal power plants by achieving higher efficiency, lower carbon emissions and lower energy penalty for incorporating different carbon capture and storage (CCS) technologies. However, due to the lack of standardised designs, current IGCC-CCS projects are hindered by higher capital expenditures limiting their commercial implementation. Therefore, the key challenge is carrying out a techno-economic optimisation of IGCC-CCS power plants to ensure compatible power generation efficiency and accessibility. This study aims to optimise the performance of a coal-based IGCC plant with two different CCS technologies (double-stage Selexol absorption cycle and Ni-based chemical looping combustion (CLC) process) through intensive process simulation, heat integration and economic analysis. Heat integration has increased the net plant efficiency by more than 12% and decreased the levelised cost of electricity (LCOE) no less than 5 cents kWh−1. The CLC technology offered near-zero carbon emissions with higher plant efficiency and lower value of LCOE. Decreasing the CO2 capture rate by Selexol caused a decrease in LCOE and an increase in the corresponding CO2 specific emissions. Therefore, an appropriate decarbonisation scenario depends on a trade-off between the degree of carbon capture and the allowed CO2 specific emissions.

Improved gasification efficiency in IGCC plants & viscosity reduction of liquid fuels and solid fuel dispersion using liquid and gaseous CO2

The applications of liquid CO2 as a slurry fluid for solid carbon feedstock (coal and biomass sludge) and impacts on gasification performance have been investigated experimentally and analytically. CO2 for rheological control of solid fuel suspensions resulted in solids loading of nearly 66 weight% (wt%) closely matching the theoretical loading of 68 wt%. As a representative example, the measured viscosity for Illinois #6 coal slurry was found to be between 31 and 87 mPa-s using CO2 compared to 62–300 mPa-s using water for loadings between 50 and 66 wt% solids, respectively. Similarly, a viscosity reduction of nearly a factor of four was measured for a heavy oil sample from the Utica basin. The viscosity of the oil at 40 °C and 100 psi measured 10.25 Pa.s yet a 0.64 wt% CO2 yielded a viscosity of 2.42 Pa-s. The gasification performance investigation was done using ASPEN® Plus simulations to understand the impact of CO2 on Integrated Gasification Combined Cycle (IGCC) plant and the gasifier performance. The results show that co-feeding CO2 into the gasifier provides higher cold gas efficiency (CGE). The baseline cold gas efficiency using steam gasification (no CO2) of Powder River Basin (PRB) coal is 78.46% whereas two cases in which CO2 was added provided CGE values of 83.22 and 81.13%. These simulations were validated via a series of Drop Tube Reactor experiments and show good agreement. The carbon conversion during gasification at 1000 ℃ increased from ∼50% to ∼68% by addition of 30% CO2.

4-E analysis of heavy oil-based IGCC

ABSTRACTThis article aims to evaluate different heavy oil derivatives as feedstock for integrated gasification combined cycle (IGCC) through energy, exergy, economic, and environmental analysis. For this purpose, the simulation of a 450 MW IGCC in Aspen Plus is performed, and optimum values of operational parameters are obtained to maximize electrical efficiency. A heavy fuel oil (Mazut), Vacuum residue (VR), and vacuum residue water slurry (VR+W) are considered as input feedstock. The thermodynamics results show that VR case with first and second law electrical efficiencies of 34.6 and 34.4% has the best electrical performance. However, by considering recoverable heat, the total efficiencies of VR+W is the maximum with 45.7 and 45.5% for energy and exergy, respectively. The economic analysis demonstrates that the total capital costs are in the same order, but because of differences in annual fuel cost for a payback period of 5 years, the electricity price should be 0.143, 0.127, and 0.125 ($/kWh) for Mazut, VR+W, and VR cases, respectively. Finally, concerning performance, economic, and environmental aspects, it seems the proposed IGCC plant with heavy oil feedstock has the ability to compete in the power generation market.

Performance analysis and carbon reduction assessment of an integrated syngas purification process for the co-production of hydrogen and power in an integrated gasification combined cycle plant

The integrated gasification combined cycle (IGCC) is prominent in coal-based power plants because of its high efficiency and environmental benefit. Because of global warming, the integration of a carbon capture process (CCP) into the IGCC is exigent. In this study, performance analysis of an integrated syngas purification process was performed for a 500 MW-class IGCC. First, various carbon capture efficiencies were investigated to elucidate the most economical carbon capture efficiency, and a carbon capture efficiency of 90% was recommended. This value includes sour gas (H2S) removal cost, and it is essential for coal-power plants regardless of carbon capture. Thus, the net carbon capture cost was calculated from the difference in the operating costs of the integrated syngas purification process with/without a CCP. The net carbon capture cost per ton of CO2 was determined as approximately 21 USD. In addition, the exergy analysis and H2 co-production from the integrated syngas purification process with pressure swing adsorption (PSA) were presented to suggest the direction of the potential process improvement and carbon reduction assessment. The study can contribute towards decision-making related to investment in near-future candidate technologies for increasing efficiency and carbon emissions.

Failure analysis for a dry-pulverized coal gasifier burner made up of Inconel 718 superalloy

Early failure of the coal gasifier burner used in integrated gasification combined cycle plants poses serious technical and safety issues. The aim of this study was to determine the causes of a failed burner based on chemical composition of material and characteristics of corrosion products and cracks. Furthermore, microstructures of the failed component at different depths were compared to investigate the phase degradation. The study found that sulfurization and chlorination were the main causes for the failure of current coal gasifier burner. Sulfidation contributed to the crack propagation, while chlorine concentrated in the corrosion layer produced significant cracks and spallations. The overheating was supposed to be responsible for the non-uniform distribution of precipitations in the failed burner from fire side to water side.

Optimization studies of coal-fired combined cycle power plant given fuel price uncertainty

Integrated gasification combined-cycle plants are considered as one of the promising directions for the development of thermal power plants using fossil fuel. Interest in this area is explained by large natural reserves of coal and minimal harmful emissions into the atmosphere during the process of generator gas combustion. The aim of the study is to make the relationship between the specific investment and the efficiency of integrated gasification combined-cycle plant and to perform the optimization researches according to the criterions of minimum electricity price.

Reduced Integration Optimization Model for Coupled Elevated-Pressure Air Separation Unit and Gas Turbine in Oxy-combustion and Gasification Power Plant

For the promising and green oxy-combustion and gasification power plant, the most efficient and assessable approach for further improvements on the current situation with less investment turned to be process optimization and integration. In this work, the gap of systematic analysis of air separation unit (ASU) and gas turbine (GT) integrations in integrated gasification combined cycle (IGCC) power plant has been fulfilled in the elevated-pressure ASU operation conditions beyond discrete case studies. Based on the conventional rigorous mathematical simulation, a series of model reductions have been proposed and applied to increase the computational flexibility. To validate the reduced model, a base case is built and settled as the benchmark, which is consistent with the industrial experiences. Afterwards, based on the reduced model, the effects of air integration on the thermal performance of IGCC power plant have been explored under the conditions of various nitrogen injection levels. The individual influences of nitrogen injection level on IGCC plant efficiency have been explored as well. To achieve best IGCC performance, the optimization of coupled air integration and nitrogen injection as a whole is completed. Based on the proposed reduced model, the three dimensional figure about systematics analysis of integration optimization for IGCC power plant is generated for the first time. Based on its two-dimensional top view, the feasible regions are identified and optimal solution is generated through nonlinear programming problem solver based on enhanced generalized reduced gradient method.

A biologically-inspired approach for adaptive control of advanced energy systems

In this article, a novel approach is proposed for integrating a Biologically-Inspired Optimal Control Strategy (BIOCS) with an Artificial Neural Network (ANN)-based adaptive component for advanced energy systems applications. Specifically, BIOCS employs gradient-based optimal control solvers in a biologically-inspired manner, following the rule of pursuit for ants, to simultaneously control multiple process outputs at their desired setpoints. Also, the ANN component captures the mismatch between the controller and the plant models by using a single-hidden-layer technique with online learning capabilities to augment the baseline BIOCS control laws. The resulting approach is a unique combination of biomimetic control and data-driven methods that provides optimal solutions for dynamic systems. The applicability of the proposed framework is illustrated via an Integrated Gasification Combined Cycle (IGCC) process with carbon capture as an advanced energy system example. In particular, a multivariable control structure associated with a subsystem of the IGCC plant simulation in DYNSIM® is addressed. The proposed control laws are derived in MATLAB®, while the plant models are built in DYNSIM®, and a previously developed MATLAB®-DYNSIM® link is employed for implementation purposes. The proposed integrated approach improves the overall performance of the process up to 85% in terms of reducing the output tracking error when compared to stand-alone BIOCS and Proportional-Integral (PI) controller implementations, resulting in faster setpoint tracking. The proposed framework thus provides a promising alternative for advanced control of energy systems of the future.

Ultrafast and Stable CO2 Capture Using Alkali Metal Salt-Promoted MgO-CaCO3 Sorbents.

As a potential candidate for precombustion CO2 capture at intermediate temperatures (200-400 °C), MgO-based sorbents usually suffer from low kinetics and poor cyclic stability. Herein, a general and facile approach is proposed for the fabrication of high-performance MgO-based sorbents via incorporation of CaCO3 into MgO followed by deposition of a mixed alkali metal salt (AMS). The AMS-promoted MgO-CaCO3 sorbents are capable of adsorbing CO2 at an ultrafast rate, high capacity, and good stability. The CO2 uptake of sorbent can reach as high as above 0.5 gCO2 gsorbent-1 after only 5 min of sorption at 350 °C, accounting for vast majority of the total uptake. In addition, the sorbents are very stable even under severe but more realistic conditions (desorption in CO2 at 500 °C), where the CO2 uptake of the best sorbent is stabilized at 0.58 gCO2 gsorbent-1 in 20 consecutive cycles. The excellent CO2 capture performance of the sorbent is mainly due to the promoting effect of molten AMS, the rapid formation of CaMg(CO3)2, and the plate-like structure of sorbent. The exceptional ultrafast rate and the good stability of the AMS-promoted MgO-CaCO3 sorbents promise high potential for practical applications, such as precombustion CO2 capture from integrated gasification combined cycle plants and sorption-enhanced water gas shift process.

Modernization of Air-Blown Entrained-Flow Gasifier of Integrated Gasification Combined Cycle Plant

The high efficiency of a combined cycle and the availability of systems for deep purification of syngas before combustion allow for the study of combined-cycle gas turbines as a promising solution to increase the efficiency and environmental friendliness of coal power engineering. The key element of the device is a gasifier. A Mitsubishi Heavy Industries gasifier is selected as an initial design for modernization, which consists in heating the blast air up to 900°C and supplying vapor with a temperature of 900°C. The impact of modernizing the gasifier characteristics is determined by using zero-, one-, and three-dimensional models. The modernization of the gasifier allows increasing the thermal power by the syngas and cold gas efficiency from 77.2 to 84.9% and increasing the ratio H2/CO from 0.34 to 0.6.

Molten Carbonate Fuel Cells for Retrofitting Postcombustion CO2 Capture in Coal and Natural Gas Power Plants

The state-of-the-art conventional technology for postcombustion capture of CO2 from fossil-fueled power plants is based on chemical solvents, which requires substantial energy consumption for regeneration. A promising alternative, available in the near future, is the application of molten carbonate fuel cells (MCFC) for CO2 separation from postcombustion flue gases. Previous studies related to this technology showed both high efficiency and high carbon capture rates, especially when the fuel cell is thermally integrated in the flue gas path of a natural gas-fired combined cycle or an integrated gasification combined cycle plant. This work compares the application of MCFC-based CO2 separation process to pulverized coal fired steam cycles (PCC) and natural gas combined cycles (NGCC) as a “retrofit” to the original power plant. Mass and energy balances are calculated through detailed models for both power plants, with fuel cell behavior simulated using a 0D model calibrated against manufacturers' specifications and based on experimental measurements, specifically carried out to support this study. The resulting analysis includes a comparison of the energy efficiency and CO2 separation efficiency as well as an economic comparison of the cost of CO2 avoided (CCA) under several economic scenarios. The proposed configurations reveal promising performance, exhibiting very competitive efficiency and economic metrics in comparison with conventional CO2 capture technologies. Application as a MCFC retrofit yields a very limited (<3%) decrease in efficiency for both power plants (PCC and NGCC), a strong reduction (>80%) in CO2 emission and a competitive cost for CO2 avoided (25–40 €/ton).