Development of magnetic activated carbon from almond shells for trinitrophenol removal from water

A process to capture carbon dioxide from air to reduce its atmospheric concentration and to mitigate climate change is studied. It is based on the absorption of carbon dioxide in a sodium hydroxide solution, its precipitation as calcium carbonate, and its release as pure gas stream through oxy-fuel calcination. The process utilizes existing commercial technologies wherever possible, particularly in the case of the absorber, whose design is carried out in detail. The analysis allows deriving material and energy balances for the whole process and determining energy demands that can be used for a technical, economical, and environmental feasibility evaluation of the technology. In particular, it indicates that the real specific energy demand is larger than the heat released to emit the same amount of CO2 by the combustion of coal, and smaller than that of methane.

Process design and energy requirements for the capture of carbon dioxide from air

Post-combustion concepts based on absorption of CO2 in aqueous amine solutions are considered the most mature technologies for CO2 capture from power plants. Several steady-state models of the absorption process exist. However, a dynamic model is required in order to study the behavior of the absorption process downstream of a power plant that operates at varying load. In this paper, a dynamic model of an absorber is presented and the results of two transient operational scenarios are shown; start-up and load reduction. In addition, issues regarding the operability of the absorber column in case of load-varying upstream power-plants are discussed. It is concluded that the present dynamic absorber model can be applied to study operability in absorber columns during the course of dynamic operation. However, a dynamic model of the total system is required in order to evaluate all operational challenges, such as load variation and high degree of heat integration between the power plant and the absorber/stripper plant.

Dynamic modeling and simulation of a CO2 absorber column for post-combustion CO2 capture

A parametric study of CO2/N2 gas separation membrane processes for post-combustion capture

Methanol poisoning causes blindness, organ failure or even death when recognized too late. Currently, there is no methanol detector for quick diagnosis by breath analysis or for screening of laced beverages. Typically, chemical sensors cannot distinguish methanol from the much higher ethanol background. Here, we present an inexpensive and handheld sensor for highly selective methanol detection. It consists of a separation column (Tenax) separating methanol from interferants like ethanol, acetone or hydrogen, as in gas chromatography, and a chemoresistive gas sensor (Pd-doped SnO2 nanoparticles) to quantify the methanol concentration. This way, methanol is measured within 2 min from 1 to 1000 ppm without interference of much higher ethanol levels (up to 62,000 ppm). As a proof-of-concept, we reliably measure methanol concentrations in spiked breath samples and liquor. This could enable the realization of highly selective sensors in emerging applications such as breath analysis or air quality monitoring. Methanol poisoning is frequent and dangerous, but selective sensors able to work in the presence of an ethanol background are missing. Here the authors propose an easy to operate sensor incorporating a separation column, able to sense toxic methanol levels in alcoholic beverages and human breath.

Christie John Geankoplis

Papers

Transport Processes and Separation Process Principles