Iron ore was studied as a CO2 absorbent. Carbonation was carried out by mechanochemical and high temperature−high pressure (HTHP) reactions. Kinetics of the carbonation reactions was studied for the two methods. In the mechanochemical process, it was analyzed as a function of the CO2 pressure and the rotation speed of the planetary ball mill, while in the HTHP process, the kinetics was studied as a function of pressure and temperature. The highest CO2 capture capacities achieved were 3.7341 mmol of CO2/g of sorbent in ball milling (30 bar of CO2 pressure, 400 rpm, 20 h) and 5.4392 mmol of CO2/g of absorbent in HTHP (50 bar of CO2 pressure, 100 °C and 4 h). To overcome the kinetics limitations, water was introduced to all carbonation experiments. The calcination reactions were studied in Argon atmosphere using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. Siderite can be decomposed at the same temperature range (100 °C to 420 °C) for the samples... [more]

Thermochemical conversion of solid wastes through gasification offers the dual benefit of production of high-value fuels and
environmentally friendly waste disposal. Waste tires in particular may be a suitable feedstock for gasification as a result of their
high energy content (LHV of approximately 34 MJ/kg, higher than coal), high volatile matter content, and low ash content. Rotary
kilns for steam gasification are a promising and technologically mature option to handle such difficult solid wastes that have a
wider range of compositions, particle sizes, and moisture contents. In this paper, we propose a novel process for production of
liquefied synthetic natural gas (SNG) from waste tires. We use experimental data available in the open literature to represent the
complex steam gasification unit operation and study three design cases: Without CCS, with precombustion CCS and with preand postcombustion CCS in two locations: USA and Norway. The thermodynamic, economic and environmen... [more]

Low-cost activated carbons were prepared from waste polyurethane foam by physical activation with CO2 for the first time and chemical activation with Ca(OH)2, NaOH, or KOH. The activation conditions were optimized to produce microporous carbons with high CO2 adsorption capacity and CO2/N2 selectivity. The sample prepared by physical activation showed CO2/N2 selectivity of up to 24, much higher than that of chemical activation. This is mainly due to the narrower microporosity and the rich N content produced during the physical activation process. However, physical activation samples showed inferior textural properties compared to chemical activation samples and led to a lower CO2 uptake of 3.37 mmol·g−1 at 273 K. Porous carbons obtained by chemical activation showed a high CO2 uptake of 5.85 mmol·g−1 at 273 K, comparable to the optimum activated carbon materials prepared from other wastes. This is mainly attributed to large volumes of ultra-micropores (<1 nm) up to 0.212 cm3·g−1 and... [more]

The potential of carbon capture and storage to provide a low carbon fossil-fueled power generation sector that complements the continuously growing renewable sector is becoming ever more apparent. An optimization of a post combustion capture unit employing the solvent monoethanolamine (MEA) was carried out using a Taguchi design of experiment to mitigate the parasitic energy demands of the system. An equilibrium-based approach was employed in Aspen Plus to simulate 90% capture of the CO2 emitted from a 600 MW natural gas combined-cycle gas turbine power plant. The effects of varying the inlet flue gas temperature, absorber column operating pressure, amount of exhaust gas recycle, and amine concentration were evaluated using signal to noise ratios and analysis of variance. The optimum levels that minimized the specific energy requirements were a: flue gas temperature = 50 °C; absorber pressure = 1 bar; exhaust gas recirculation = 20% and; amine concentration = 35 wt%, with a relative im... [more]

The petroleum coke gasification integrated gasification combined cycle power plant (petcoke-IGCC) is a promising avenue for disposal of the ever-growing amount of stockpiled petroleum coke. In this work, we present a novel techno-economic and life cycle assessment of the process operated with carbon capture and sequestration. The proposed petcoke-to-electricity plant is designed and simulated in Aspen Plus v10. The proposed power plant was compared against coal integrated gasification combined cycle (coal-IGCC) and supercritical pulverized coal power plants operated with carbon capture and sequestration. The results showed that although the efficiency of the coal-IGCC plant is higher than the petcoke-IGCC plant, the higher energy density of the petcoke and lower resource costs were such that the levelized cost of electricity of petcoke-IGCC was lower than coal-IGCC. Furthermore, the feed flow rate of petcoke to the petcoke-IGCC process is approximately 15% lower than the coal feed rate... [more]

The application of circulating fluidized bed technology in calcium looping (CaL) requires that CaO-based sorbents should be manufactured in the form of spherical pellets. However, the pelletization of powdered sorbents is always hampered by the problem that the mechanical strength of sorbents is improved at the cost of loss in CO₂ sorption performance. To promote both the CO₂ sorption and anti-attrition performance, in this work, four kinds of pore-forming materials were screened and utilized to prepare sorbent pellets via the extrusion-spheronization process. In addition, impacts of the additional content of pore-forming material and their particle sizes were also investigated comprehensively. It was found that the addition of 5 wt.% polyethylene possesses the highest CO₂ capture capacity (0.155 g-CO₂/g-sorbent in the 25th cycle) and mechanical performance of 4.0 N after high-temperature calcination, which were about 14% higher and 25% improved, compared to pure calcium hydrate pellet... [more]

One of the largest engineering challenges of our time is finding technical solutions that permit the use of our energy resources in a sustainable way. In order to achieve meaningful and positive change, new energy systems must adhere to the triple bottom line of sustainability. This means that new technical solutions must be economically, socio-politically, and environmentally sustainable, such that they can be rapidly adopted and accepted. The engineering literature is full of a great many technical proposals for new energy systems, but it turns out to be quite hard to objectively look at them all, see through the hype, and decide which are the best and most promising technologies in which to invest our research and development dollars. In this talk, I will present a case study with the results of our recent meta-study covering over 100 candidate electricity generation systems with carbon dioxide capture, in order to determine which are the most promising classes of technologies. I wi... [more]

The rapid development of modern society has resulted in an increased demand for energy, mainly from fossil fuels. The use of this source of energy has led to the accumulation of carbon dioxide (CO₂) in the atmosphere. In this context, microalgae culturing may be an effective solution to reduce the CO₂ concentration in the atmosphere, since these microorganisms can capture CO₂ and, simultaneously, produce bioenergy. This work consists of a techno-economic assessment of a microalgal production facility integrated in a petrochemical complex, in which established infrastructure allows efficient material and energy transport. Seven different scenarios were considered regarding photosynthetic, lipids extraction and anaerobic digestion efficiencies. This analysis has demonstrated six economically viable scenarios able to: (i) reduce CO₂ emissions from a thermoelectric power plant; (ii) treat domestic wastewaters (which were used as culture medium); and (iii) produce lipids and electrical and... [more]

In this study, a novel biomass-gas-and-nuclear-to-liquids (BGNTL) process is proposed. In this process, nuclear heat is used as the heat source of a steam methane reforming (SMR) process. In a prior work, a rigorous model was developed for the integrated nuclear heat and steam methane reforming process in the gPROMS software package. This model was applied to simulate the integrated nuclear heat and SMR section of BGNTL in Aspen Plus within the other process sections. The BGNTL process was considered for producing different fuels including gasoline & diesel or dimethyl ether (DME). Carbon capture and sequestration (CCS) is considered as an optional section. The performance of the BGNTL process was compared against a non-nuclear process called biomass-and-gas-to-liquids (BGTL). The efficiency, economics, and environmental impact analyses show that the BGNTL process to produce DME is the most efficient, economic and environmentally friendly process among the considered designs. As a resu... [more]

This work explores the technical feasibility and economic profitability of converting petroleum coke (petcoke) and natural gas to liquid fuels via Fischer-Tropsch synthesis. Different petcoke conversion strategies were examined to determine the conversion pathway which can be competitive with current market prices with little or no adverse environmental impacts. Three main design approaches were considered: petcoke gasification only, combined petcoke gasification and natural gas reforming through traditional processing steps, and combined petcoke gasification and natural gas reforming by directly integrating the gasifier’s radiant cooler with the gas reformer. The designs investigated included scenarios with and without carbon capture and sequestration, and with and without CO2 emission tax penalties. The performance metrics considered included net present value, life cycle greenhouse gas emissions, and the cost of CO2 avoided. The design configuration that integrated natural gas refor... [more]

A series of carbon aerogels were synthesized by polycondensation of resorcinol and formaldehyde, and their structure was adjusted by managing solution concentration of precursors. Carbon aerogels were characterized by X-ray diffraction (XRD), Raman, Fourier transform infrared spectroscopy (FTIR), N₂ adsorption/desorption and scanning electron microscope (SEM) technologies. It was found that the pore structure and morphology of carbon aerogels can be efficiently manipulated by managing solution concentration. The relative micropore volume of carbon aerogels, defined by Vmicro/Vtol, first increased and then decreased with the increase of solution concentration, leading to the same trend of CO₂ adsorption capacity. Specifically, the CA-45 (the solution concentration of precursors is 45 wt%) sample had the highest CO₂ adsorption capacity (83.71 cm³/g) and the highest selectivity of CO₂/N₂ (53) at 1 bar and 0 °C.

Developing “good” membrane modules and materials is a key step towards reducing the cost of membrane-based CO2 capture. While this is traditionally being done through incremental development of existing and new materials, this paper presents a new approach to identify membrane materials with a disruptive potential to reduce the cost of CO2 capture for six potential industrial and power generation cases. For each case, this approach first identifies the membrane properties targets required to reach cost-competitiveness and several cost-reduction levels compared to MEA-based CO2 capture, through the evaluation of a wide range of possible membrane properties. These properties targets are then compared to membrane module properties which can be theoretically achieved using 401 polymeric membrane materials, in order to highlight 73 high-potential materials which could be used by membrane development experts to select materials worth pushing towards further development once practical conside... [more]