Detailed Design and Economic Evaluation of a Cryogenic Air Separation Unit with Recent Literature Solutions

Abstract

Cryogenic air separation is a well-established technology. However, due to its associated energy intensity and hazardousness, new studies are always emerging on this topic. Nevertheless, economic feasibility studies of cryogenic separation plants are still scarce. Studies of this type are essential because installing an air separation unit can also be considered at the design stage of other common industrial projects, such as oxidation/ combustion processes and ammonia production. This study aims to elucidate the technical and economic aspects of a real-size air separation unit and analyze the feasibility of incorporating some alternatives recently proposed in the literature, such as multistage compression with and without an organic Rankine cycle for energy saving, integrated argon column, energy recovery systems in turbines, and a PSA unit for CO 2 removal, and in the implementation of a new plant. For this, we performed a rigorous simulation and a robust economic evaluation. Thus, it was possible to identify the main bottlenecks of the process, which may become the subject for future work. As a result, the relevance of the compression (34−36%) and refrigeration (54−55%) stages in the capital cost and the importance of conscious electricity (29−32% of the production costs) and maintenance spending for the process' economic viability were shown. Flowsheets and economic analysis are presented in detail so that they could be used as a base case for future developments in this field.

Selective Adsorption of Oxygen from Humid Air in a Metal–Organic Framework with Trigonal Pyramidal Copper(I) Sites

“…Intriguingly, two sets of features were generated upon O 2 dosing: one pair at 1131 and 1051 cm −1 and another pair at 1073 and 993 cm −1 for the O 2 -and 18 O 2 -dosed samples, respectively. The isotopic shifts for both features are consistent with predictions based on the simple harmonic oscillator model for O 2 (peaks for 18 O 2 -dosed material are predicted to be at 1066 and 990 cm −1 ). As such, we assign both sets of features to the O 2 species.…”

“…To elucidate the features arising from bound O 2 , we conducted identical experiments in which Cu 2.4 -MFU-4l was dosed at 263 K with 8 mbar of either natural abundance O 2 (99.8% 16 O 2 ) or 18 O 2 (97 atom % 18 O). Spectra were then collected at 5 K intervals as the sample was warmed from 263 to 298 K. A set of difference spectra generated by subtracting the 18 O 2 -dosed spectra from the O 2 -dosed spectra are plotted in Figure 3a and clearly show positive and negative peaks corresponding to 16 O 2 and 18 O 2 vibrations, respectively. Intriguingly, two sets of features were generated upon O 2 dosing: one pair at 1131 and 1051 cm −1 and another pair at 1073 and 993 cm −1 for the O 2 -and 18 O 2 -dosed samples, respectively.…”

Advanced Design of Ammonia Production Processes from LNG: Efficient and Economical Cold Energy Utilization Methods

“…Nitrogen can be sold in liquid and gaseous forms. Even though the price of liquid nitrogen is almost 10 times higher than that of gaseous nitrogen, additional equipment for liquefaction is needed . In this study, nitrogen is assumed to be sold in gaseous form, and nitrogen for sale is set to have the same pressure and flow rate and show a difference of less than 5 °C in all designs.…”

“…Even though the price of liquid nitrogen is almost 10 times higher than that of gaseous nitrogen, additional equipment for liquefaction is needed. 54 In this study, nitrogen is assumed to be sold in gaseous form, and nitrogen for sale is set to have the same pressure and flow rate and show a difference of less than 5 °C in all designs. The LCOA is calculated as follows produced in all three designs is constant at 6.53 kg/s with a purity of 97.5%; therefore, SEC exhibits the same tendency as the overall energy consumption.…”

Modular Framework for Simulation-Based Multi-objective Optimization of a Cryogenic Air Separation Unit

“…An exergy and economic analysis was carried out using Aspen Plus. Finally, Young et al performed a detailed design and economic evaluation of a cryogenic ASU, identifying the relevance of each stage when computing the capital expenditures. Although open source state-of-the-art platforms, such as FOQUS, , allow the interaction with commonly used chemical engineering process modeling software (Aspen Plus, gPROMS, Thermoflex) for simulation-based optimization, the functionalities of such platforms are still under development.…”