Chemical Reactor Research Articles

Chaotic mixing coupled electromagnetic heating in a tubular reactor

To address the need for enhanced biochemical reactions and overcome the shortcomings associated with passive and active mixer fabrication, reactor designs must utilize the coupled mixing concept to address the lack of insufficient heat and mass transfer through notable alterations of the physical properties. This study introduces a tubular microwave reactor based on chaotic flow dynamics, attempting to combine the concept of active and passive mixing to stimulate the development of eddy and secondary flows through electromagnetic fields and geometric disturbance enhance heat and mass transfer. Experiments and simulation analysis validate the validity of the prediction model, and reveal the fluid flow, mixing, electromagnetic and thermal characteristics and their synergistic mechanism, and shows the potential to enhance the mass and heat transfer performance at low Reynolds number, which provides a new idea for the design of chemical reactors and biological analysis.

Application of continuous stirring tank reactor for controllable synthesis of Cu7S4 nanocrystals

As a typical model for a chemical reactor in industry, the continuous stirring tank reactor has been widely used in waste-water treatment, industrial catalysis, and biological fermentation as well as great application prospects in the synthesis of nanomaterials. In this report, a convenient lab-scale continuous stirring tank reactor was assembled and utilized to synthesize Cu7S4 nanocrystals by injecting cupric bromide and sulfur solution in the presence of ascorbic acid and polyethyleneimine at 60 °C. The morphology control of Cu7S4 nanocrystals was accomplished by simply adjusting the agitation speed. Cu7S4 nanofibers with an average diameter of 48 ± 4.42 nm and a length of several micrometers were obtained at 80 rpm. Cu7S4 nanoplates with a thickness of 89 ± 13.56 nm and a plane size of 103 ± 16.47 nm were synthesized at 90 rpm, and the size of the nanoplates was regulated by continuously increasing the agitation speed from 90 rpm to 1000 rpm. Furthermore, the influences of two additional conditions (the mean residence time and the concentration of the feed solution) on the morphology of Cu7S4 nanocrystals, were also investigated. Therefore, these results could facilitate the understanding of the behaviors of CSTR in the synthesis of Cu7S4 nanocrystals and could also provide an important reference for the continuous synthesis of other nanoparticles.

Numerical analysis of unsteady free convection of Al2O3 inside a tubular reactor under the influences of exothermic reaction, and inclined MHD as an application to chemical reactor

This paper delves into the numerical investigation of aluminum oxide–water nanofluid thermal and dynamic performances under the influences of magnetic field application and chemical reaction, utilizing the Finite Element Method within a circular enclosure containing three inner tubes, as an application to the heat exchanging phenomenon between the reactive shell of the cavity and the surface of the triple tubes. Various governing parameters were studied for their interaction on the nanofluid flow and heat transmission rate within the proposed geometry, including the Rayleigh parameter (103≤Ra≤105), Hartmann parameter (0≤Ha≤61), nanoparticles concentration (0≤∅≤6×10-2), magnetic rotational angle (0o≤γ≤90o), and Frank-Kamenetskii parameter (0≤Fk≤3). The results indicated that raising Ra from 103 to 105 results in expediting the nanofluid velocity by 10.62 % and 100 % respectively as well as raising the total heat transfer efficiency. The nanofluid speed was also increased by 28.57 % when Fk has to further increase to a value of 3. When there was no exothermic activity present, the rate of heat transmission was at its lowest, and it was greater when the Fk value was 3. Similarly, there were discernible impacts in various areas of the geometry as the Ha number intensified and the Nuavg decreased. Improvements in local and mean Nusselt parameters are observed when the concentration of nanoparticles is increased, suggesting better heat transfer, achieving an increase by 7 % in the average Nusselt number. This research emphasizes the importance of nanoparticle concentration in raising the medium’s rates of heat transmission, contributing to advancements in energy storage development.

Polycrystalline inclusion-free growth of thick, lattice-matched SiGeC with high substitutional Carbon concentrations up to 2%

Lattice-matched SiGeC with ~20% of Ge was grown at 550°C, 10 Torr on a 300 mm Si substrate in an industrial standard Reduced Pressure Chemical Vapor Deposition reactor using commercially available Si2H6/GeH4/SiH3CH3 precursors. Thicknesses exceeding 250 nm resulted in cluster formation in SiGeC with [C]Sub~2.0% and [C]Int~0.4%, with a surface density up to 6.13x106 µm-2. Room temperature photoluminescence measurements showed that the clusters were non-radiative defects and Transmission Electron Microscopy, using the ASTAR system, proved they were polycrystalline with random orientation. Cluster-free growth was achieved for 1 µm thick SiGeC with [C]Sub~1.0% and no interstitial carbon atoms, however, without lattice-matched growth on a Si substrate. Injecting HCl during a co-flow process resulted in a smooth surface with a RMS roughness of 0.23 nm and a reduction of [C]Intfrom ~0.7% down to ~0.1%, close to the detection limit of X-ray Photoelectron Spectroscopy at 0.1%. This led to a significant cluster surface density reduction down to 1.15x104 µm-2. The injection of HCl caused an increase in the Ge concentration from 19.7% up to 28.9% and a non-lattice-matched growth. A Cyclic Deposition Etch (CDE) process resulted in no [C]Int reduction, but significantly reduced the cluster surface density down to 4.60x104 µm-2. CDE-grown SiGeC was lattice-matched to the Si substrate and yielded a smooth surface with a RMS roughness of 0.22 nm. This enabled the growth of high crystalline quality, thick, lattice-matched layers on a 300 mm Si substrate with material properties beyond pure Si.

Boron Delta-Doping in Si : B Stacks By RP-CVD Epitaxy

Low resistivity materials are required for advanced MOS or equivalent technologies. High boron in-situ doped Si epitaxy is known to create defects that increase the resistivity. Boron delta-doping (Si:B epitaxy alternating with boron saturation layers) is a potential solution to overcome this limitation. Using the delta-doping process at 750 °C in a Reduced Pressure Chemical Vapor Deposition reactor, a resistivity two times lower than that without delta-doping (8.9x10-4 Ω.cm and 1.86x10-3 Ω.cm respectively) was achieved. SIMS characterization measured a total boron concentration of 3.3x1021 at.cm-3. However, the delta-doping processes , as a function of the soaking volume (product of B2H6 flow and saturation time), resulted in low crystal quality and highly stressed layers. Moreover, thin layers were observed by TEM likely due to the formation of the SiBx phase at each saturation layer. For an equivalent soaking volume, a better crystal quality was obtained with a high B2H6 flow and short saturation time.

Numerical investigation of different transverse Rib shapes on thermal convection in a channel filled with nanofluid

With the growing interest in energy optimization, corrugated surfaces are arguably an excellent choice, finding applications in areas as diverse as heat exchangers, automobiles, building energy efficiency, and chemical reactors. However, due to the poor thermal properties of conventional fluids, heat transfer is limited. The introduction of nanoparticles into fluids is a promising solution to improve their thermal performance. This paper does a detailed numerical analysis of how different factors affect the forced convection heat transfer in a two-dimensional ribed channel. The shape of the ribs is one of the factors that are looked at, along with some new parameters like e/H, which is the ratio of rib height to channel height, and L2/P, which is the test section to the pitch between the ribs. The aim is to determine the optimum geometry that maximizes the Nusselt number while minimizing the pressure drop. The study also examines the effects of nanoparticle type and concentration on heat transfer and fluid flow characteristics. To this end, the continuity, momentum, and energy equations were solved with the finite volume method using the SIMPLE scheme with the k-ε turbulence model at different Reynolds numbers ranging from 4000 – 14,000. The results indicate that triangular ribs with ratios e/H = 0.15 and L2/P = 4 increase the Nusselt number by 63.3 % while reducing the pressure drop by 22 % compared with the other cases. The improvement in heat transfer in the water-SiO2 case was the greatest compared with the other nanofluids tested. Particle size fraction and Reynolds number increased the Nusselt number in ribbed channels by 20.7 % compared with water.

Polynomial chaos expansions on principal geodesic Grassmannian submanifolds for surrogate modeling and uncertainty quantification

In this work we introduce a manifold learning-based surrogate modeling framework for uncertainty quantification in high-dimensional stochastic systems. Our first goal is to perform data mining on the available simulation data to identify a set of low-dimensional (latent) descriptors that efficiently parameterize the response of the high-dimensional computational model. To this end, we employ Principal Geodesic Analysis on the Grassmann manifold of the response to identify a set of disjoint principal geodesic submanifolds, of possibly different dimension, that captures the variation in the data. Since operations on the Grassmann require the data to be concentrated, we propose an adaptive algorithm based on Riemannian K-means and the minimization of the sample Fréchet variance on the Grassmann manifold to identify “local” principal geodesic submanifolds that represent different system behavior across the parameter space. Polynomial chaos expansion is then used to construct a mapping between the random input parameters and the projection of the response on these local principal geodesic submanifolds. The method is demonstrated on four test cases, a toy-example that involves points on a hypersphere, a Lotka-Volterra dynamical system, a continuous-flow stirred-tank chemical reactor system, and a two-dimensional Rayleigh-Bénard convection problem.

Towards Low NOx Emissions Performance of A 65KW Recuperated Gas Turbine Operated on 100% Hydrogen

Abstract This work supports the development of a low NOx emission 65 kW natural gas turbine capable of operating on 100% hydrogen. This gas turbine has been demonstrated to operate from cold start to full load on up to 30% hydrogen mixed into natural gas with single digit ppm NOx emissions. To reach operation on 100% hydrogen, injectors specifically designed to 1) avoid challenges with flashback and 2) be field retrofittable were developed and tested. Successful operation of the engine from cold start to full load on 100% hydrogen was demonstrated. To support the development, a chemical reactor network (CRN) is used in conjunction with experimental injector mixing characterization. A strategy to account for variation in mixing performance was developed and utilized with the CRN to connect NOx emissions to the injector mixing performance. Measured fuel concentration profiles and the CRN model was used to infer the effects of mixing on NOx emission. The results illustrate how NOx emissions are directly influenced by local fuel rich regions found at the injector outlet. The CRN model can thus be used to screen injector designs and infer NOx performance and will be used to guide the development of injectors for hydrogen that can attain desired fuel distributions, concentrations, and velocities. The results affirm the direction needed to attain improved mixing and to operate at overall leaner conditions made possible by the stabilizing features inherent to hydrogen.

High-Yield WS2 Synthesis through Sulfurization in Custom-Modified Atmospheric Pressure Chemical Vapor Deposition Reactor, Paving the Way for Selective NH3 Vapor Detection.

Nanostructured transition metal dichalcogenides have garnered significant research interest for physical and chemical sensing applications due to their unique crystal structure and large effective surface area. However, the high-yield synthesis of these materials on different substrates and in nanostructured films remains a challenge that hinders their real-world applications. In this work, we demonstrate the synthesis of two-dimensional (2D) tungsten disulfide (WS2) sheets on a hundred-milligram scale by sulfurization of tungsten trioxide (WO3) powder in an atmospheric pressure chemical vapor deposition reactor. The as-synthesized WS2 powders can be formulated into inks and deposited on a broad range of substrates using techniques like screen or inkjet printing, spin-coating, drop-casting, or airbrushing. Structural, morphological, and chemical composition analysis confirm the successful synthesis of edge-enriched WS2 sheets. The sensing performance of the WS2 films prepared with the synthesized 2D material was evaluated for ammonia (NH3) detection at different operating temperatures. The results reveal exceptional gas sensing responses, with the sensors showing a 100% response toward 5 ppm of NH3 at 150 °C. The sensor detection limit was experimentally verified to be below 1 ppm of NH3 at 150 °C. Selectivity tests demonstrated the high selectivity of the edge-enriched WS2 films toward NH3 in the presence of interfering gases like CO, benzene, H2, and NO2. Furthermore, the sensors displayed remarkable stability against high levels of humidity, with only a slight decrease in response from 100% in dry air to 93% in humid environments. Density functional theory and Bayesian optimization simulations were performed, and the theoretical results agree with the experimental findings, revealing that the interaction between gas molecules and WS2 is primarily based on physisorption.

Promoting human-centered manufacturing through Lean Ergonomics – a structural equation model for ergonomics and management data

ABSTRACT The Stress-Strain Concept (SSC) describes central mechanisms in Lean Ergonomics (LE) and Human Factors Engineering (HFE). The SSC can create additional value through content and methodological enrichment based on current economic, technological, and demographic constraints. This article uses the SSC to explore mechanisms of interactions of productivity and ergonomics in empirical shop floor data. Ergonomic (Borg, NASA-Task Load Index (N-TLX), Ergonomic Assessment Worksheet (EAWS), Health, Age) and business data (normalized and absolute standard deviations of work process times) were collected for 24 manual work processes operating large-scale chemical reactors. Data is analyzed using several Structural Equation Models (SEM). Stress (EAWS) and – depending on Health – Physical Strain with a model quality of Adjusted Goodness-of-Fit ≥0.9 were identified as statistically significant regressors for time data. In addition, carry-over effects from ergonomics to productivity were identified in an autoregressive model. Fit indices are in the good to acceptable range.

Development of GeSn epitaxial films with strong direct bandgap luminescence in the mid-wave infrared region using a commercial chemical vapor deposition reactor

Germanium tin (GeSn) is a material of interest for electronic and photonic device applications, but its development and commercialization have been limited by material quality issues and lack of availability from epitaxy suppliers. In this paper, we report initial studies in optimizing GeSn films deposited on a Ge buffer layer grown on 200-mm diameter silicon (Si) substrates with an ASM Epsilon 2000 chemical vapor deposition reactor designed for commercial production. Using a single-step growth process, a Sn content up to 22% near the surface of a GeSn film was achieved due to the increase in Sn incorporation via strain relaxation. A two-step growth process resulted in a bilayer structure with a nearly 100% relaxation on the first layer, followed by a higher quality GeSn layer with 18% Sn as evident by a high photoluminescence intensity emitting in the mid-wave infrared region at 3.2 μm at 20 K.

Effects of axisymmetric confinement on vortical structures emanating from round turbulent jets

Confined jets occur in many engineering applications including combustion chambers, jet pumps, and chemical reactors. The effects of axisymmetric confinement on the vortical structures identified in a turbulent jet are investigated using large eddy simulation at a Reynolds number of 30 000 (based on nozzle exit conditions) and expansion ratio (chamber-to-nozzle diameter ratio) of five. The results obtained from the confined jet are compared with those of a free jet under the same nozzle exit flow conditions. A prominent recirculation zone forms between the expanding jet and the confining wall, resulting in early shear layer distortion and a shorter interaction length in the confined jet (0.85 jet diameters) compared to the free jet (1.15 jet diameters). Using the λ2 criterion for vortex identification, two dominant structural modes are identified in the near-exit region of the free jet: ring and helical modes. However, in the confined jet, the helical mode is absent, and the turbulent confined fluid accelerates the breakup of the ring vortices. The interaction of the secondary line vortices with the breaking structures leads to the formation of new hairpin-like vortices, which also contribute to further vortex breakup. These results explain the enhanced mixing performance of confined jets as the mixing is directly tied to the breakup of large vortical structures. Proper orthogonal decomposition modes are also presented to identify the structures/events with the highest contribution to the total turbulent kinetic energy in both flow fields.

Brinkman–Bénard convection in a box with temperature modulation

A bounded porous box saturated with Newtonian fluid and subjected to a sinusoidal temperature gradient has various practical applications, such as solar energy storage, groundwater remediation, food processing, and chemical reactors. We address the generalization of the classical Rayleigh–Bénard convection problem in a horizontal fluid layer in an infinitely large domain heated from below to a finite three-dimensional box. We also look into a more intricate form of the modulated Rayleigh–Bénard problem in which the temperature at the bottom boundary varies sinusoidally. The Rayleigh number quantifies the non-sinusoidal part of the temperature gradient, while the amplitude and frequency of modulation describe the sinusoidal one. The critical Rayleigh number is determined using linear and nonlinear stability analyses; for the latter, the energy method is used. There is a possibility of subcritical instabilities, as evidenced by the energy stability estimates being lower than the linear ones. Furthermore, eigenvalues are obtained as a function of aspect ratios, modulation amplitude, and frequency for varying Darcy numbers. Modulation amplitude more significantly triggers a change in flow patterns at the onset of convection compared to the effect of other parameters. Considering water-saturated porous media made up of different materials, we report the critical temperature difference between lower and upper surfaces required for the onset of convection. In addition, a comparison between such a temperature difference obtained from linear theory and the energy method is also provided in the same manner. It is observed that subharmonic instability occurs for all considered porous media packed densely or sparsely.

Numerical investigation on a novel milli-sized heat sink equipped by twisted elliptical tubes

Thermal management in some small chemical reactors is essential to achieve a final high-quality product and heat sinks can play a remarkable role in dissipating heat from such systems. In this regard, this study attends to evaluate the conjugate heat transfer problem in a heat sink equipped by twisted elliptical tubes (TETs). The effects of significant parameters such as Reynolds number (Re = 250, 350, 500, 700 and 950) and twist ratio (TR = 2.5, 5 and 10) on hydrothermal and thermodynamics performance of the novel heat sink are investigated. The swirling flow is the main reason of fluid particles migration from hot surface to cold one and vice versa, leading a better heat transfer occurs at the expense of not significant pressure loss augmentation. The results revealed that the TETs are responsible of more wall temperature uniformity and avoids generating hot spots. Compared with plain elliptical tubes, the presence of TETs inside heat sink improves the heat transfer rate and enlarges the pressure drop by 1.08–2.03 times and by 1.02–1.92 times, respectively. In addition, the TETs decrease the entropy generation rate inside heat sink and the best value of second law efficiency is about 35 %, detected at TR = 2.5 and Re = 250.

Reducing sludge formation by enhancing biological decay of biomass: a mathematical model

Abstract We investigate a model for an activated sludge process that contains a chemical reactor unit attached to a bioreactor. Inside the chemical reactor unit, a process takes place which increases the decay coefficient of heterotrophic biomass. This mimics a number of experimental techniques which are used to decrease the mass of sludge. Such techniques are of growing interest as the activated sludge process produces large volumes of sludge; the costs associated with its disposal are significant. Our primary interest is to investigate how the operation of the chemical reactor unit changes the steady-state concentrations of both the total suspended solids within the biological reactor and the chemical oxygen demand in the effluent stream. The operation of a chemical reactor unit always increases the value of chemical oxygen demand in the effluent stream. The behaviour of the total suspended solids is more complicated; in some cases, the operation of the CRU increases the total suspended solids. For a fixed value of the chemical oxygen demand in the influent stream, we show that both the percentage reduction in the total suspended solids and the chemical oxygen demand in the effluent stream are increasing functions of the soluble substrate in the feed. The same trends occur when the influent composition is fixed, and the disintegration rate inside the chemical reactor unit is increased. This leads to dichotomic behaviour, decreasing the total suspended solids increases the chemical oxygen demand in the effluent stream. There are two consequences of this behaviour. Firstly, there are some waste streams that can not be cleaned using the process configuration considered in this paper. Secondly, the imposition of a target value for the chemical oxygen demand in the effluent stream imposes a maximum achievable reduction in the total suspended solids in the biological reactor. Higher reductions can not be achieved without causing the chemical oxygen demand in the effluent stream to exceed the target value.

Model‐based fault diagnosis for safety‐critical chemical reactors: An experimental study

AbstractThis article presents an experimental application of fault detection, isolation, and estimation in a chemical reactor system, introducing a functional observer‐based approach without the need for linear approximation. The residual signal generators, functioning as disturbance‐decoupled functional observers, provide fault size estimates and enable fault isolation through multiple generators operating independently. The experimental study focuses on the 3‐Picoline oxidation process, deriving a discrete‐time model, and constructing specific residual generators for coolant inlet temperature and feed concentration faults. Fault diagnosis employs Fast Fourier Transform (FFT) filtering and Generalized Likelihood Ratio (GLR), facilitating on‐the‐fly detection during the experiment. The effectiveness of fault detection, disturbance decoupling, and estimation is experimentally validated.

Surface Carbon Formation and its Impact on Methane Dry Reforming Kinetics on Rhodium‐Based Catalysts by Operando Raman Spectroscopy

AbstractA mechanism for carbon deposition and its impact on the reaction kinetics of Methane Dry Reforming (MDR) using Rhodium‐based catalysts is presented. By integrating Raman spectroscopy with kinetic analysis in an operando‐annular chemical reactor under strict chemical conditions, we discovered that carbon deposition on a Rh/α‐Al2O3 catalyst follows a nucleation‐growth mechanism. The dynamics of carbon aggregates at the surface is found to be ruled by the CO2/CH4 ratio and the inlet CH4 concentration. The findings elucidate the spatiotemporal development of carbon aggregates on the catalyst surface and their effects on catalytic performance. Furthermore, the proposed mechanism for carbon formation shows that the influence of CO2 on MDR kinetics is an indirect result of carbon accumulation over time frames exceeding the turnover frequency, thus reconciling conflicting reports in the literature regarding CO2′s kinetic role in MDR.

Advanced overpressure protection: A concept for smart controlled safety pressure relief systems

Safety devices such as safety valves and rupture discs are crucial components in protecting chemical reactors from exothermic runaway reactions and overpressure scenarios. While traditional safety valves operate autonomously, controlled safety devices offer the potential for dynamic adjustments to optimize system performance. However, existing safety valves and controlled safety pressure relief systems (CSPRS) lack flexibility in a fixed relief pressure and stroke positions. This article introduces a new smart overpressure protection device (SmOP) with an adaptable safety device controlled through a combination of model predictive control and PID-control. Tested extensively in a high-pressure loop, the SmOP demonstrates rapid and precise control behavior, ensuring reactor safety as well increasing the efficiency. The control concept, based on model prediction followed by PID-correction, is validated through endurance tests and various opening conditions. Results indicate the SmOP's robustness against external disturbances and its potential for industrial applications. Future work includes developing a failsafe concept and laboratory tests with chemical reactions to further validate the SmOP's performance.

ENTROPY-OPTIMIZED FLOW OF COUPLE STRESSES IN AN POROUS INCLINED PIPE WITH UNIFORM MAGNETIC FIELD AND MIXED CONVENTION

Abstract The research aims to investigate the entropy-optimized flow of couple stresses in a porous inclined pipe exposed to a transverse constant magnetic field and mixed convection. It focuses on understanding the thermodynamic efficiency and fluid behaviour under convective boundary conditions, contributing to improved designs in engineering applications where such flows are relevant. The aim is to enhance heat transfer efficiency in industrial processes such as chemical reactors, heat exchangers, and geothermal systems, while also improving filtration systems for applications like water purification and oil recovery. By subjecting the flow to a uniform magnetic field and mixed convection, nonlinear governing equations arise due to mixed convection. We linearize these equations using a quasi-linearization approach and solve them using Chebyshev spectral collocation. Our analysis focuses on thermodynamic phenomena like entropy generation and the Bejan number, which have implications for the efficiency and sustainability of industrial processes. We visualize temperature and axial velocity profiles across various parameter ranges to understand the fluid's behaviour under the influence of magnetic fields and porous materials. As the magnetic parameter increases, there is a decrease in fluid velocity and temperature. However, the opposite tendency is seen for the couple stress viscosity ratio parameter. We also observe irreversibility dominating heat transfer at the pipe wall, while fluid friction irreversibility dominates around the pipe's centre. This research contributes to advancing our understanding of thermodynamic processes in complex fluid systems and has practical implications for optimizing industrial processes and developing more efficient filtration systems.

Comparative analysis of eight urea-electricity-heat-cooling multi-generation systems: Energy, exergy, economic, and environmental perspectives

The Haber-Bosch process for urea production is known for its significant carbon emissions. While the chemical looping ammonia generation method presents a potential alternative, its technical and economic feasibility still requires further investigation. This paper conducts a comparative analysis of eight renewable energy-driven urea-electricity-heat-cooling multi-generation systems by developing their energy, exergy, economic, and environmental evaluation models. Considering the fluctuation in renewable energy resources, an annual evaluation of the different systems is conducted based on a monthly time scale. The results indicate that systems based on the Haber-Bosch process have higher average energy and exergy efficiencies of 60–80 % and 40–50 %, respectively. For the chemical looping ammonia generation process, the respective efficiencies are 50–70 % and 30–40 %. Additionally, the system integrating the Haber-Bosch reaction, reduction reactor, and solid oxide fuel cell yields the highest energy and exergy efficiencies among the eight systems, at 68.2 % and 45.78 %, respectively. However, it is inferior to the multi-generation system integrating the chemical looping ammonia generation process in terms of economic and environmental performance. In addition, the system integrating the chemical looping ammonia generation process and solid oxide fuel cell has the shortest discounted payback period of 8 years, with annual revenue and net present value of 32.63 and 11.66 MUSD, respectively. While the operating expenditures of the Haber-Bosch (12.6–15.7 MUSD) are lower than those of the chemical looping ammonia generation process (14.0–17.5 MUSD), its capital expenditures (382.0–410.8 MUSD) are significantly higher than those of the chemical looping ammonia generation process (302.4–307.3 MUSD). Furthermore, the conducted environmental evaluation shows that the multi-generation system integrating the chemical looping ammonia generation process and reduction reactor exhibits lower overall carbon emissions (0.013 t CO2/t urea) compared to the state-of-the-art method of oxy-fuel coal-fired power plant for urea synthesis.