• Energy Research
• chemical engineering close

Abstract Among various configurations of fossil fuel power plants with carbon dioxide capture, this paper focuses on pre-combustion capture technology applied to an Integrated Gasification Combined Cycle power plant using gas–liquid absorption. The paper proposes a detailed study and optimization of plant design (column height and packed dimensions) with CO 2 capture process using different solvents as: aqueous solutions of alkanolamine, dimethyl ethers of polyethylene glycol, chilled methanol and N-Methyl-2-pyrolidone. By developing simulations in Aspen Plus, the following performance results of these physical and chemical solvents, mentioned above, are discussed: overall energy consumption (power consumption, heating and cooling agent consumption), CO 2 specific emissions, net electric power output and plant efficiency. The paper presents as well, the total investment capital cost of an IGCC coal mixed with biomass (sawdust) power plant generating 425–450 MW net electricity with (70% CO 2 capture, 80% CO 2 capture and 90% CO 2 capture) and without pre-combustion CO 2 capture. Simulation results show that for evaluated solvents for CO 2 capture, the physical solvent, dimethyl ethers of polyethylene glycol, is more energy efficient that the other physical and chemical solvents investigated. Regarding the economic study, implementation of pre-combustion CO 2 capture on IGCC plant, using dimethyl ethers of polyethylene glycol, leads to an increase of the capital cost with about 19.55% for 70% CO 2 capture, 20.91% for 80% CO 2 capture and 22.55% for 90% CO 2 capture.

In this work, a comprehensive mathematical model was developed in order to evaluate the CO2 capture process in a microporous polypropylene hollow-fiber membrane countercurrent contactor, using monoethanolamine (MEA) as the chemical solvent. In terms of CO2 chemical absorption, the developed model showed excellent agreement with the experimental data published in the literature for a wide range of operating conditions (R2 > 0.96), 1–2.7 L/min gas flow rates and 10–30 L/h liquid flow rates. Based on developed model, the effects of the gas flow rate, aqueous liquid absorbents’ flow rate and also inlet CO2 concentration on the removal efficiency of CO2 were determined. The % removal of CO2 increased while increasing the MEA solution flow rate; 81% of CO2 was removed at the high flow rate. The CO2 removal efficiency decreased while increasing the gas flow rate, and the residence time in the hollow-fiber membrane contactors increased when the gas flow rate was lower, reaching 97% at a gas flow rate of 1 L‧min−1. However, the effect was more pronounced while operating at high gas flow rates. Additionally, the influence of momentous operational parameters such as the number of fibers and module length on the CO2 separation efficiency was evaluated. On this basis, the developed model was also used to evaluate CO2 capture process in hollow-fiber membrane contactors in a flexible operation scenario (with variation in operating conditions) in order to predict the process parameters (liquid and gaseous flows, composition of the streams, mass transfer area, mass transfer coefficient, etc.).

AbstractIntegrated Gasification Combined Cycle (IGCC) is a technology for power generation in which the 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 production. The hot GT flue gases are sent to Heat Recovery Steam Generator (HRSG) for steam generation. Additional power is produces by expanding the steam generated in a steam turbine.Carbon capture and storage (CCS) technologies are expected to play a significant role in the coming decades for reducing the greenhouse gas emissions. Integrated Gasification Combined Cycle is one of the power generation technologies having the highest potential to capture carbon dioxide with the low penalties in term of plant energy efficiency and cost. The modification of the IGCC design for carbon capture can be done in various plant concepts considering the carbon capture method to be used (e.g. pre- and post-combustion capture, syngas chemical looping etc.).This paper investigates various carbon capture methods suitable to be applied for an IGCC plant for power generation. The coal blended with biomass (sawdust) based IGCC case study investigated in the paper produces around 400–500 MW net electricity with more than 90% carbon capture rate. An important focus of the paper is concentrated on overall energy efficiency optimization of the IGCC plant concepts with various carbon capture options by better heat and power integration of the main plant sub-systems (e.g. steam integration between gasification island, syngas conditioning line and the steam cycle, influence of heat and power demand for Acid Gas Removal unit etc.). A particular attention of the paper is focused on the quality specification for the captured carbon dioxide stream considering various capture options but also the storage options (enhanced oil recovery, storage in depleted oil and gas fields, saline aquifers etc.).