The Systematic Design of CO2 Capture Processes Applied to the Oxidative Coupling of Methane

The oxidative coupling of methane is the catalytic conversion of methane into ethene. Carbon dioxide is generated as a reaction by-product and must be removed from the gaseous stream. In this paper, the application of a hybrid carbon dioxide removal process including absorption with amines and gas separation membranes is investigated through simulations and cost estimations.DFG, 53182490, EXC 314: Unifying Concepts in Catalysi

Multi-Scale Analysis of Integrated C1 (CH4 and CO2) Utilization Catalytic Processes: Impacts of Catalysts Characteristics up to Industrial-Scale Process Flowsheeting, Part II: Techno-Economic Analysis of Integrated C1 Utilization Process Scenarios

In the second part of this paper (Part II), the potentials and characteristics of an industrial-scale Oxidative Coupling of Methane (OCM) process integrated with CO2-hydrogenation, ethane dehydrogenation, and methane reforming processes are highlighted. This novel process concept comprises a direct conversion of methane to ethane and ethylene and further conversion of the resulted carbon dioxide and remaining unreacted methane, respectively, to methanol and syngas. In this context, the selected experimental results of the catalytic CO2-hydrogenation to methanol reported in the first part of this paper (Part I), were utilized to represent its industrial-scale performance. The experimental results of the mini plant-scale operation of an OCM reactor and CO2 removal units along with the experimental and industrial data available for representing the operation and performance of all process-units in the integrated process structures were utilized to perform a comparative techno-economic environmental analysis using Aspen-Plus simulation and an Aspen Economic Process Analyzer. The experimental procedure and the results of testing the sequence of OCM and CO2-hydrogenation reactors are particularly discussed in this context. It was observed that in the sequential operation of these reactors, ethylene will be also hydrogenated to ethane over the investigated catalysts. Therefore, the parallel-operation of these reactors was found to be a promising alternative in such an integrated process. The main assumptions and the conceptual conclusions made in this analysis are reviewed and discussed in this paper in the light of the practical limitations encountered in the experimentations. In the context of a multi-scale analysis, the contributions of the design and operating parameters in the scale of catalyst and reactor as well as in the process-scale represented by analyzing the type and operating conditions of the downstream-units and the process-flowsheets on the economic and environmental performance of the integrated process structures were studied. Moreover, the economic impacts of extra ethylene and methanol produced respectively via the integrated ethane dehydrogenation and CO2-hydrogenation sections were analyzed in detail. The required capital investment was found to be even smaller than the yearly operating cost of the plant. The environmental impacts and sustainability of the integrated OCM process were found to be enhanced by securing a minimum direct CO2-emission and energy-efficient conversion of CO2 and the unreacted CH4, respectively, to methanol and syngas. Besides producing such value-added by-products, efficient operation of downstream process-units was secured by minimizing the energy usage and ethylene losses. Under the considered conditions in this analysis, the specifications of the finally selected integrated OCM process structure, providing the fastest return of investments (less than 8 years), are highlighted.DFG, 53182490, EXC 314: Unifying Concepts in Catalysi

Sequential Flowsheet Optimization: Maximizing the Exergy Efficiency of a High-Pressure Water Scrubbing Process for Biogas Upgrade

Biogas is an important renewable energy source and potential raw material for the chemical industry. Its utilization frequently requires a treatment and/or upgrade step. The aim here is to maximize the exergy efficiency of a high-pressure water scrubbing process for upgrading biogas into biomethane by coupling a sequential modular simulation flowsheet with different optimization algorithms. By setting adequate operating pressures, and reducing cycle water and stripping air flowrates, an exergy efficiency of 92.4% is reached.DFG, 53182490, EXC 314: Unifying Concepts in Catalysi

Techno-economic assessment of different routes for olefins production through the oxidative coupling of methane (OCM): Advances in benchmark technologies

his paper addresses the techno-economic assessment of two technologies for olefins production from naphtha and natural gas. The first technology is based on conventional naphtha steam cracking for the production of ethylene, propylene and BTX at polymer grade. The unused products are recovered in a boiler to produce electricity for the plant. The plant has been designed to produce 1 MTPY of ethylene. In the second case, ethylene is produced from natural gas through the oxidative coupling of methane (OCM) in which natural gas is fed to the OCM reactor together with oxygen from a cryogenic air separation unit (ASU). The overall reactions are kinetically controlled and the system is designed to work at about 750–850 °C and close to 10 bar. Since the overall reaction system is exothermic, different layouts for the reactor temperature control are evaluated. For the naphtha steam cracking plant, the energy analysis shows an overall conversion efficiency of 67% (with a naphtha-to-olefins conversion of 65.7%) due to the production of different products (including electricity), with a carbon conversion rate of 70%. The main equipment costs associated with naphtha steam cracking are represented by the cracker (about 30%), but the cost of ethylene depends almost entirely on the cost associated with the fuel feedstock. In case of the OCM plant, the overall energy conversion efficiency drops to maximally 30%. In the studied plant design, CO2 capture from the syngas is also considered (downstream of the OCM reactor) and therefore the final carbon/capture efficiency is above 20%. The cost of ethylene from OCM is higher than with the naphtha steam cracking plant and the CAPEX affects the final cost of ethylene significantly, as well as the large amount of electricity required.The authors are grateful to the European Union’s HORIZON2020 Program (H2020/2014-2020) for the financial support through the H2020 MEMERE project under the grant agreement n° 679933

Effective scale-up of oily sludge bioremediation from a culture-based medium to a two-phase composting system using an isolated hydrocarbon-degrading bacterium: effect of two-step bioaugmentation

The scale-up feasibility of oily sludge (OS) biodegradation from a culture-based medium to a new two-stage composting process bioaugmentated with an indigenous isolated strain was surveyed. First, the bacterial strain (Enterobacter hormaechei strain KA6) was isolated from OS, and then its ability in biomass production and oil degradation in culture-based medium was evaluated. Finally, the strain was used for bioaugmentation in composting reactors which included four in-vessel experiments with the initial total petroleum hydrocarbon (TPHs) concentrations between 10 and 30 g kg-1. The strain was added twice to the composting reactors which lasted 16 weeks including the primary composting stage (PCS) (first inoculation) and the secondary composting stage (SCS) (second inoculation). It was observed that the strain degraded 58.67, 74.79, 45.33, 10.66, and 5.92% of 1, 2, 3, 4, and 5% oil concentrations, respectively, in culture-based medium during 7 days. Regarding OS bioremediation in the composting experiments, a total TPH removal rate of 65.83–81.50% was also reached after the two-stage duration of 16 weeks. Due to the second bioaugmentation stage, the SCS showed higher TPH removal efficiency than the PCS. The study confirmed the effectiveness of the scaling-up of a culture-based medium to a composting process for treating OS

The Systematic Design of CO2 Capture Rocesses Applied to the Oxidative Coupling of Methane

The oxidative coupling of methane is the catalytic conversion of methane into ethene. Carbon dioxide is generated as a reaction by-product and must be removed from the gaseous stream. In this paper, the application of a hybrid carbon dioxide removal process including absorption with amines and gas separation membranes is investigated through simulations and cost estimations

The Systematic Design of CO2 Capture Rocesses Applied to the Oxidative Coupling of Methane

The oxidative coupling of methane is the catalytic conversion of methane into ethene. Carbon dioxide is generated as a reaction by-product and must be removed from the gaseous stream. In this paper, the application of a hybrid carbon dioxide removal process including absorption with amines and gas separation membranes is investigated through simulations and cost estimations

Biodegradation of heavy oily sludge by a two-step inoculation composting process using synergistic effect of indigenous isolated bacteria

The impact of two-step inoculation of indigenous strains and their synergistic effect in the scaling-up of petroleum hydrocarbons biodegradation from a mineral-based medium (MBM) to a two-phase composting process were investigated. After isolating the strains KA3 and KA4 from heavy oily sludge (HOS), their emulsification index (E24), bacterial adhesion to hydrocarbon (BATH), and oil degradation efficiency were evaluated in the MBM. Then, they were inoculated twice into the composting bioreactors lasted for the primary 8 weeks as the first phase (FP) and subsequent 8 weeks as the second phase (SP). The results indicated that the consortium of the two strains degraded 16-61% of crude oil (1-5% concentration) in the MBM. In the composting reactors, removals of 20 g kg−1 initial concentration of total petroleum hydrocarbons (TPH) were found to be 63.95, 61.00, and 89.35% for the strains KA3, KA4, and their consortium, respectively. The computed biodegradation constants indicated the synergistic effect of the two strains and the effectiveness of the second-step inoculation. The study demonstrated the successful scaling-up of HOS biodegradation from MBM to the two-phase composting process through two-step inoculation of the isolated strains

Direct conversion of CO2 to light olefins over FeCo/XK-ϒAL2O3 (X = La, Mn, Zn) catalyst via hydrogenation reaction

The conversion of CO2 to value-added products such as olefins is one of the suggested strategies in carbon dioxide utilization for tackling climate change. Although hydrogenation of CO and CO2 to olefins has been extensively studied, still further research is required to design more active and selective catalyst for this process. In this study, we implemented a modification strategy by using multi-metallic promoters (K-X, X: La, Mn, Zn) in the Fe-Co/ϒ-Al2O3 network to develop more efficient catalyst formulations for olefin synthesis from CO2 hydrogenation. X-ray diffraction, N2-physisorption, hydrogen temperature-programmed reduction, NH3-temperature-programmed desorption, thermogravimetric analysis and X-ray photoelectron spectroscopy were performed to study the physicochemical properties of the synthesized catalysts. The results indicate that the application of assistant promoters influences the catalyst reducibility and surface structure and also changes the product distribution. The addition of La and Mn improves slightly the electron density of iron species and suppresses H2 adsorption and hence shifted the observed product selectivity toward olefins and suppressed methane formation. Moreover, the presence of Zn facilitates the reduction properties and increases the H2 consumption and therefore, led to higher methane formation of 44.9% in comparison to the catalysts using La and Mn. The inclusion of assistant promoters reduced the conversion of CO2 from 30% (FeCo-K) to 22% and enhanced the olefins selectivity. Graphical abstract: [Figure not available: see fulltext.

Selective CO2-Hydrogenation using a membrane reactor

We present a novel membrane reactor (MR) concept for CO2 -hydrogenation to methanol application, in which CO2 is supplied from a CO2 -rich gas stream via a membrane and is distributed along the catalytic packed bed, where it reacts with hydrogen over a CuO-ZnO/Al2O3 catalyst to produce methanol. The performance of the reactor was investigated using a set of two-fluid model simulations. The simulation results showed that the fine distribution of CO2 improved the selectivity of methanol production by a value of 6 % for the studied range of the operating conditions