Novel process design and techno-economic simulation of methanol synthesis from blast furnace gas in an integrated steelworks CCUS system

A novel process design and techno-economic performance assessment for methanol synthesis from Blast Furnace Gas (BFG) is presented. Methanol synthesis using BFG as a feedstock, based on direct CO2 hydrogenation at commercial scale was simulated using Aspen Plus software to evaluate its technical performance and economic viability. The applied process steps involve first conditioning BFG using adsorption based desulfurisation, water-gas shift, dehydration, then separation of components into N2, CO2 and H2 rich streams using pressure swing adsorption. The H2 stream and a fraction of the CO2 stream are fed to a methanol synthesis system, while the remaining CO2 may be considered for geological storage in a Carbon Capture, Utilization and Storage (CCUS) case, or not in a Carbon Capture Utilization (CCU) case. Techno-economic analysis confirms methanol production from BFG is economically attractive under certain conditions, with Levelized Cost of Methanol production (LCOMeOH) calculated to be 344.61 £/tonne-methanol, and costs of CO2 avoided of - 20.08 £/tonne-CO2 for the CCU process and 9.01 £/tonne-CO2 for the CCUS process when using a set of baseline engineering assumptions. Sensitivity analysis of the process simulation explores opportunities for optimising the methanol synthesis system in terms of the impact of reactor size and/or recycle ratio on LCOMeOH. Economic viability of the CCU(S) processes is also found to be highly dependent on the cost of the feedstock BFG. Future cost savings as compared to business-as-usual steel production by 2030 in consideration of expected increases in the carbon price are estimated to be 10.59 £/tonne-steel for CCU and 24.61 £/tonne-steel for CCUS

Chemical-looping combustion in a dual bed packed bed configuration

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A novel reactor configuration for packed bed chemical-looping combustion of syngas

This study reports on the application of chemical looping combustion (CLC) in pressurized packed bed reactors using syngas as a fuel. High pressure operation of CLC in packed bed has a different set of challenges in terms of material properties, cycle and reactor design compared to fluidized bed operation. However, high pressure operation allows the use of inherently more efficient power cycles than low pressure fluidized bed solutions. This paper quantifies the challenges in high pressure operation and introduces a novel reactor concept with which those challenges can be addressed. Continuous cyclic operation of a packed bed CLC system is simulated in a 1D numerical reactor model. Importantly, it is demonstrated that the temperature profiles that can occur in a packed bed reactor as a result of the different process steps do not accumulate, and have a negligible effect on the overall performance of the system. Moreover, it has been shown that an even higher energy efficiency can be achieved by feeding the syngas from the opposite direction during the reduction step (i.e. countercurrent operation). Unfortunately, in this configuration mode, more severe temperature fluctuations occur in the reactor exhaust, which is disadvantageous for the operation of a downstream gas turbine. Finally, a novel reactor configuration is introduced in which the desired temperature rise for obtained hot pressured air suitable for a gas turbine is obtained by carrying out the process with two packed bed reactor in series (two-stage CLC). This is shown to be a good alternative to the single bed configuration, and has the added advantage of decreasing the demands on both the oxygen carrier and the reactor materials and design specification

Molecular mechanism and intrinsic kinetics of catalytic steam reforming of methane over ceria-zirconia as an efficient catalyst for H2 production with in situ CO2 capture

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Kinetic and structural requirements for a CO2 adsorbent in sorption enhanced catalytic reforming of methane. Part I: Reaction kinetics and sorbent capacity

This paper presents a fundamental model-based analysis for the applicability of integration of a highly active Rh/CeaZr1-aO2 catalyst with two candidate CO2 sorbents for pure H2 production in low temperature sorption-enhanced steam reforming of methane. K-promoted hydrotalcite and lithium zirconate solids are considered in the investigation as CO2 sorbents. The process is analyzed using multi-scale modeling levels of a heterogeneous particle-based model, a heterogeneous bulk-scale model, and a homogenous bulk-scale model. The presence of this active catalyst dictates strict requirements on the sorbent in terms of fast adsorption kinetics for an efficient process performance. The maximum CH4 conversion enhancement is determined to be a strong function of sorption kinetics. This enhancement is not affected by a higher sorbent capacity at slow adsorption kinetics. The process is studied using two fixed bed configurations of an integrated dual function particle and an admixture bed of catalyst/sorbent particles. Optimal operating conditions for the hydrotalcite-based system are identified to provide CH4 conversion of 98% with high H2 purity of 99.8% and low CO2 contamination

Chemisorption working capacity and kinetics of CO2 and H2O of hydrotalcite-based adsorbents for sorption-enhanced water-gas-shift applications

The adsorption behavior of carbon dioxide and water on a K-promoted hydrotalcite based adsorbent has been studied by thermogravimetric analysis with the aim to better understand the kinetic behavior and mechanism of such material in sorption enhanced water-gas shift reactions.\u3cbr/\u3e\u3cbr/\u3eThe cyclic adsorption capacity was measured as a function of temperature (300–500 °C), pressure (0–8 bar) and the cycle time. Both species interact at elevated temperatures with the adsorbent. The history of the adsorbent (pretreatment/desorption conditions) has a profound influence on its sorption capacity. Slow desorption kinetics determine the sorption capacity during cyclic operation, where a high temperature during the desorption and long half-cycle times can increase the cyclic working capacity for both CO2 and H2O significantly. Accounting for the sorbent history and the definition of adsorption capacity are very important features when comparing sorption capacities to values reported in literature. The adsorbent shows very high capacities for H2O compared to CO2 which has not been reported in the literature up to now. The mechanism for H2O and CO2 adsorption seems to be a different one. Whereas H2O adsorption seems to follow the principles of a simple physisorption mechanism, CO2 adsorption can only be explained by a chemical reaction with the adsorbent. Working isotherms (cyclic working capacity at isothermal conditions at different pressures) of both CO2 and H2O were measured up to 8 bar total pressure. Higher partial pressures increase the cyclic working capacity of the adsorbent up to 0.47 mmol/g for CO2View the MathML source(PCO2=8bar) and 1.06 mmol/g for H2O (View the MathML sourcePH2O=4.2bar) at 400 °C after 30 min of adsorption followed by 30 min of dry regeneration with N2.\u3cbr/\u3

Chemisorption of H2O and CO2 on hydrotalcites for sorptionenhanced water-gas-shift processes

Thermogravimetric analysis and breakthrough experiments in a packed bed reactor were used to validate a developed adsorption model to describe the cyclic working capacity of CO2 and H2O on a potassium-promoted hydrotalcite, a very promising adsorbent for sorption-enhanced water-gas-shift applications. Four different adsorption sites (two sites for CO2, one site for H2O and one equilibrium site for both species) were required to describe the mass changes observed in the TGA experiments. The TGA experiments were carried out at operating temperatures between 300 and 500 °C, while the total pressure in the reactor was kept at atmospheric pressure. Cyclic working capacities for different sites and the influence of the operating conditions on the cyclic working capacity were studied using the developed model. A higher operating temperature leads to a significant increase in the cyclic working capacity of the sorbent for CO2 attributed to the increase in the desorption kinetics for CO2. The model was successfully validated with experiments in a packed bed reactor at different operating temperatures

Influence of material composition on the CO\u3csub\u3e2\u3c/sub\u3e and H\u3csub\u3e2\u3c/sub\u3eO adsorption capacities and kinetics of potassium-promoted sorbents

\u3cp\u3eTwo different potassium-promoted hydrotalcite (HTC)-based adsorbents and a potassium-promoted alumina sorbent were investigated using thermogravimetric analysis (TGA) and different characterization methods in order to study CO\u3csub\u3e2\u3c/sub\u3e and H\u3csub\u3e2\u3c/sub\u3eO adsorption capacity and kinetics. A higher Mg content improves the cyclic working capacity for CO\u3csub\u3e2\u3c/sub\u3e due to the higher basicity of the material. The initial adsorption rate for CO\u3csub\u3e2\u3c/sub\u3e is very fast for all sorbents, but for sorbents with higher MgO content, this fast-initial adsorption is followed by a slower CO\u3csub\u3e2\u3c/sub\u3e uptake probably caused by the slow formation of bulk carbonates. A longer half-cycle time can therefore increase the CO\u3csub\u3e2\u3c/sub\u3e cyclic working capacity for sorbents with a higher MgO content. Potassium-promoted alumina has a very stable CO\u3csub\u3e2\u3c/sub\u3e cyclic working capacity at different operating temperatures compared to the potassium-promoted HTC's. Usually a higher operating temperature increases the desorption kinetics for a HTC-based adsorbent, but not for potassium-promoted alumina. HTC-based adsorbents show the highest cyclic working capacity for H\u3csub\u3e2\u3c/sub\u3eO. The adsorption kinetics for H\u3csub\u3e2\u3c/sub\u3eO are not influenced by the material composition, indicating that the mechanism behind the adsorption of H\u3csub\u3e2\u3c/sub\u3eO is different compared to CO\u3csub\u3e2\u3c/sub\u3e. Depending on the material composition, adsorption of steam at high operating temperatures (>500 °C) results in an irreversible decomposition of carbonate species. Steam can reduce the temperature where usually K\u3csub\u3e2\u3c/sub\u3eCO\u3csub\u3e3\u3c/sub\u3e is irreversibly decomposed resulting in a significantly reduced cyclic working capacity, which is very important concerning the use of these sorbents for sorption-enhanced water-gas shift processes.\u3c/p\u3

On the CO2 and H2O chemisorption on hydrotalcite-based adsorbents for sorption-enhanced water-gas-shift processes.

Thermogravimetric analysis (TGA) was used to study the adsorption phenomena of CO2 and H2O on a hydrotalcite-based adsorbent to be used for sorption-enhanced Water-Gas-Shift (SEWGS). The adsorption of CO2 and H2O and the interaction between the two can be described when considering the presence of at least three different sites (2 for CO2 and 1 for H2O) participating in the adsorption phenomena at elevated temperatures. The experiments confirm that the regeneration conditions are crucial for activating more sites for CO2 adsorption and are therefore the limiting factor for the cyclic working capacity of the adsorbent