This article provides an independent cost estimate for uranium production from seawater through the braid-type adsorbent recovery system proposed by the Japan Atomic Energy Agency (JAEA). Production costs were developed with standard engineering cost estimation techniques using vendor data and plant design and operational data. The analysis includes life cycle discounted cash flows, economies of scale, and propagation of uncertainties. A reference case based on the Japan Atomic Energy Agency assessment, with a fresh adsorbent capacity of 2 kgU/t ads and 6 recycles, yielded a production cost of $1230/kg uranium with a 95 percent confidence interval of [$1030/kg U, $1430/kg U] when component cost uncertainties alone were considered. Sensitivity studies confirmed that adsorbent capacity, number of recycles, and capacity degradation are major cost drivers. If capacity and number of recycles increases to 6 kg U/t ads and 20, respectively, with no degradation and unchanged adsorbent production costs, the uranium production cost drops to $299/kg U.
A low-order amine scrubbing model was developed for an intercooled absorber and advanced flash stripper configuration with piperazine solvent. The low-order lumped parameter model uses semi-empirical thermodynamics and ratebased mass transfer and embeds reaction kinetics in a constant overall transfer coefficient. The predicted off-design steady state of this model is compared to a high-order Aspen Plus simulation for 100−85% power plant load. The difference in CO 2 removal rate between the two models is less than 1% when power plant load is greater than 94%. The removal rate is systematically overpredicted in the low-order model because a constant CO 2 mass transfer coefficient in the absorber leads to an overprediction of absorber performance at part-load operation. Compared to pilot plant data, the low-order model captures the dynamic response of a step change in the stripper pressure control valve. The characteristic time of the total CO 2 inventory is found to be 77 min, compared to a total liquid residence time of 48 min. The low-order model sufficiently represents process behavior and will be used in future work to screen regulatory process control strategies.
8Chemical absorption using aqueous amine is one of the most feasible options for post-combustion 9 CO 2 capture. One of the main challenges of this technology is its high energy requirements. Absorber 10 intercooling was considered as a viable method to offer benefits in terms of solvent absorption 11 capacity and mass transfer efficiency in CO 2 absorption processes. However, the effectiveness of 12 absorber intercooling on overall energy requirements depends on other factors such as lean loading 13 and liquid to gas ratio. This study evaluates the benefits of using two different configurations of 14 absorber intercooling, i.e. "in-and-out" and "recycled" intercooling when using 30 wt % aqueous 15 monoethanolamine (MEA) to capture 90% CO 2 from a natural gas fired turbine with 4 mol % CO 2 .
16The Lean CO 2 loading was varied from 0.15 to 0.42 (mol CO 2 /mol MEA) to determine the lean 17 loading at which the application of intercooling is most significant. Absorber intercooling provides
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