Coal-based Integrated Gasification Combined Cycle Research Articles

CO2-Selective Membrane Reactor Process for Water-Gas-Shift Reaction with CO2 Capture in a Coal-Based IGCC Power Plant

Integrated gasification combined cycle (IGCC) power plants enable pre-combustion carbon capture to reduce CO2 emissions. Membrane water gas shift reactors can intensify these processes by converting raw syngas to H2 with simultaneous CO2 capture in one unit. This paper reports process design and techno-economic analysis (TEA) for a membrane reactor (MR) process with a CO2 selective ceramic-carbonate dual-phase (CCDP) membrane for water-gas shift (WGS) reaction with CO2 capture for a IGCC power plant. The target performance includes CO conversion >95%, hydrogen purity >90%, CO2 purity >95%, and carbon capture >90%. Using a commercial catalyst and a CCDP membrane, the MR can achieve the performance target at 750oC and space velocity of 250h-1. The outcome of the process design and TEA shows that the CCDP MR has an operating cost of $24M/year, significantly lower than that for the conventional processes (40M$/year). However, the MR process has a higher capital cost ($1,007M) than the conventional process ($527M) because of the higher cost of the CCDP MRs. Modeling analysis shows a MR with higher CO2 permeance can deliver the target at a higher space velocity and lower membrane surface area to catalyst volume ratio, leading to a significantly reduced MR capital costs.

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.

Chemical Looping for Pre-combustion and Post-combustion CO2 Capture

In the paper, performance models are developed for two CO2 capture technologies – (a) a chemical looping combustion (CLC) process for pre-combustion CO2 capture from the syngas of a coal-based integrated gasification combined cycle (IGCC) power plant; and (b) a CaL cycle for post-combustion CO2 capture from a pulverized coal (PC) power plant –and used to conduct detailed thermodynamic analyses of IGCC and PC power plants with the respective chemical looping-based CO2 capture processes. Results from the performance models are used to estimate the capital cost ($/kW) and operating cost ($/MWh) of each capture process as well as the complete power plant. Results of the case studies using the techno-economic model indicate that, in terms of performance, both of the chemical looping technologies modelled here are thermodynamically much better than conventional CO2 capture technologies, resulting in lower overall plant energy penalties. However, both the technologies are found to be more capital-intensive. As a result, the overall cost (capital and LCOE) of plants with chemical looping CO2 capture technologies is greater than or similar to the conventional technologies.

Performance of Multiple-Injection Dry Low-NOx Combustors on Hydrogen-Rich Syngas Fuel in an IGCC Pilot Plant

The successful development of coal-based integrated gasification combined cycle (IGCC) technology requires gas turbines capable of achieving the dry low nitrogen oxides (NOx) combustion of hydrogen-rich syngas fuels for low emissions and high plant efficiency. Mitsubishi Hitachi Power Systems, Ltd. (MHPS) has been developing a “multiple-injection burner” to achieve the dry low-NOx (DLN) combustion of hydrogen-rich syngas fuels. The purposes of this paper are to present the test results of a multican combustor equipped with multiple-injection burners in an IGCC pilot plant, and evaluate combustor performance by focusing on the effects of flame shapes. The syngas fuel produced in the plant contained approximately 50% carbon monoxide, 20% hydrogen, and 20% nitrogen by volume. In the tests, the combustor with slenderer flames achieved lower NOx emissions of 10.9 ppm (at 15% oxygen), reduced combustor liner and burner plate metal temperatures, and lowered combustion efficiency at the maximum gas turbine load. The test results showed that the slenderer flames were more effective in reducing NOx emissions and liner/burner plate metal temperatures. A comparison with the diffusion-flame combustor demonstrated that the multiple-injection combustors achieved the dry low-NOx combustion of the syngas fuel in the plant.

The cost of CO2 capture and storage

The objective of this paper is to assess the current costs of CO2 capture and storage (CCS) for new fossil fuel power plants and to compare those results to the costs reported a decade ago in the IPCC Special Report on Carbon Dioxide Capture and Storage (SRCCS). Toward that end, we employed a similar methodology based on review and analysis of recent cost studies for the major CCS options identified in the SRCCS, namely, post-combustion CO2 capture at supercritical pulverized coal (SCPC) and natural gas combined cycle (NGCC) power plants, plus pre-combustion capture at coal-based integrated gasification combined cycle (IGCC) power plants. We also report current costs for SCPC plants employing oxy-combustion for CO2 capture—an option that was still in the early stages of development at the time of the SRCCS. To compare current CCS cost estimates to those in the SRCCS, we adjust all costs to constant 2013 US dollars using cost indices for power plant capital costs, fuel costs and other O&M costs. On this basis, we report changes in capital cost, levelized cost of electricity, and mitigation costs for each power plant system with and without CCS. We also discuss the outlook for future CCS costs.

High Efficiency Integrated Gasification Combined Cycle with Carbon Capture via Technology Advancements and Improved Heat Integration

Adding CO2 capture to fossil-fuelled power generation results in significant plant efficiency penalties, impacting the performance and economics of the plant. However, many of the public domain studies do not consider technology advancements and optimal heat and power integration. This paper evaluates the efficiency impact of improvements in technology selection, energy recovery and heat integration on the overall thermal efficiency of IGCC schemes with pre-combustion CO2 capture.A previous study[1] has shown that the application of emerging or newer technologies and improved process/heat integration to coal-based integrated gasification combined cycle (IGCC) with carbon capture could achieve a cumulative efficiency improvement of more than six percentage points when compared with a current design. This paper looks in more detail at how some of these savings can be achieved and identifies improvements which could be achieved in the near term. In particular, the application of a modified shift system, Thiopaq O&G sulphur removal technology and a novel CO2 wash system have been included in the scope. (For oil and gas applications, the Thiopaq O&G process is licensed by Paqell BV, a joint-venture company of Shell Global Solutions International B.V. and Paques BV).

Assessment of calcium-based chemical looping options for gasification power plants

This paper evaluates various calcium-based chemical looping concepts to be applied in Integrated Gasification Combined Cycle (IGCC) plants for decarbonised energy vectors poly-generation (with emphasis on power generation and hydrogen and power co-generation). Two calcium-based chemical looping configurations were analysed. The first concept is based on post-combustion capture using the flue gases resulted from the power block (combined cycle gas turbine). The second concept is based on pre-combustion capture, the calcium-based chemical looping systems being used simultaneous to capture carbon dioxide (by sorbent enhanced water gas shift) and to concentrate the syngas energy in the form of hydrogen-rich gas.The paper assess in details coal-based IGCC with calcium carbonate looping cycle used for power generation. Net power output is in the range of 550–600 MW with more than 95% carbon capture rate. Critical design and operation factors like process integration, heat and power integration, quality specification of captured CO2 stream were evaluated in details. The hydrogen and power co-generation scenario (in the range of 0–200 MW hydrogen) was also evaluated as a potential way to improve the plant flexibility. IGCC power plant without carbon capture was also considered to quantify the energy penalty for carbon capture cases.

Integrated assessment of IGCC power generation technology with carbon capture and storage (CCS)

IGCC (Integrated Gasification Combined Cycle) is a power generation technology in which the solid feedstock is partially oxidized with oxygen and steam to produce syngas. In a conventional IGCC design without carbon capture, the syngas is purified for dust and hydrogen sulphide removal and then it is sent to a CCGT (Combined Cycle Gas Turbine) for power generation. CCS (Carbon capture and storage) technologies are expected to play a significant role in the coming decades for reducing the greenhouse gas emissions. IGCC is one of the power generation technologies having the highest potential to capture CO2 with low penalties in term of plant energy efficiency, capital and operational costs.This paper investigates the most important techno-economic and environmental indicators (e.g. power output, ancillary consumption, energy efficiency, CW consumption, normalised mass and energy balances and plant construction materials, capital and O&M (operational & maintenance) costs, specific CO2 emissions, cost of electricity, CO2 removal and avoidance costs etc.) for IGCC with CCS. Coal-based IGCC cases produce around 400–450 MW net electricity with 90% carbon capture rate. Similar IGCC plants without CCS were presented as references. Future IGCC developments for energy vectors poly-generation were also presented.

Evaluation of energy integration aspects for IGCC-based hydrogen and electricity co-production with carbon capture and storage

Integrated Gasification Combined Cycle (IGCC) is a power generation technology in which the solid feedstock is partially oxidized with oxygen and steam to produce syngas. In a conventional IGCC design without carbon capture, the syngas is purified for dust and hydrogen sulphide removal and then sent to a Combined Cycle Gas Turbine (CCGT) for power generation. Carbon capture technologies are expected to play an important role in the coming decades for reducing the greenhouse gas emissions. In a modified IGCC design for carbon capture, the syngas is catalytically shifted to maximize the hydrogen level and to concentrate the carbon species in the form of carbon dioxide which can be later captured in a pre-combustion arrangement. After carbon dioxide capture, the hydrogen-rich syngas can be either purified in a Pressure Swing Adsorption (PSA) unit and exported to the external customers (e.g., chemical industry, PEM fuel cells) or used in a CCGT for power generation. This paper investigates the most important energy and process integration issues for hydrogen and electricity co-production scheme based on coal gasification process with carbon capture and storage (CCS). The evaluated coal-based IGCC case produces around 400 MW net electricity and has a flexible hydrogen output in the range of 0–200 MW (LHV) with a 90% carbon capture rate. The principal focus of the paper is on the evaluation of energy integration aspects so as to maximize the overall plant energy efficiency. Optimization includes heat and power integration of the main plant sub-systems (e.g., integration of steam generated in gasification island, with the requirements for syngas treatment, power generation in the combined cycle, best use of PSA tail gas in the power block, heat and power demand for acid gas removal unit, integration of air separation unit and gas turbine compressor etc.), sensitivity analysis (e.g., influence on ambient conditions).

Techno-economic evaluation of the coal-based integrated gasification combined cycle with CO2 capture and storage technology

Abstract Performance estimation is performed for the coal-based integrated gasification combined cycle (IGCC) with CO 2 capture and storage (CCS) technology. A two-stage CO 2 -selective membrane separation process is implemented to achieve efficient CO 2 removal. These evaluations allow clarification of the determining factors in the promotion of the industrial application of the IGCC with CCS.

Egypt: contract awarded for gas treatment plant using new technology

Adding CO2 capture to fossil-fuelled power generation results in significant plant efficiency penalties, impacting the performance and economics of the plant. However, many of the public domain studies do not consider technology advancements and optimal heat and power integration. This paper evaluates the efficiency impact of improvements in technology selection, energy recovery and heat integration on the overall thermal efficiency of IGCC schemes with pre-combustion CO2 capture.A previous study[1] has shown that the application of emerging or newer technologies and improved process/heat integration to coal-based integrated gasification combined cycle (IGCC) with carbon capture could achieve a cumulative efficiency improvement of more than six percentage points when compared with a current design. This paper looks in more detail at how some of these savings can be achieved and identifies improvements which could be achieved in the near term. In particular, the application of a modified shift system, Thiopaq O&G sulphur removal technology and a novel CO2 wash system have been included in the scope. (For oil and gas applications, the Thiopaq O&G process is licensed by Paqell BV, a joint-venture company of Shell Global Solutions International B.V. and Paques BV).

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.