Conference abstract – Dynamic modelling and testing of two water washes in series.

Abstract

An amine-based CO2 capture plant may cause harmful emissions to the atmosphere, and it is important to measure and control the emissions of amines and products resulting from their degradation during the process. The present work is a part of the SCOPE and AURORA projects and presents modelling and experimental results from the SINTEF CO2Lab pilot plant located in Trondheim, Norway [1]. The focus of the present work has been on a water wash system in the pilot plant. This water wash system is located downstream the absorber, consisting of two external sections (see Figure 1).

The gas from the top of the absorber is about 60°C and is directed to the two sections AW3 and AW4 before it leaves the plant at about 35°C. This outlet temperature must be close to the outlet temperature of the DCC such that the water balance in the pilot plant is maintained. Each section consists of 1.5m of structured packing using circulating water with cooling for temperature control. The cooling of the gas provides water condensation in the packing and increases the liquid level in the sumps. In AW4, the excess liquid is pumped to section AW3. The water in that section will then be diluted. The excess liquid in AW3 is pumped back to the absorber.

In both projects, the CESAR1 solvent with 1.5 M piperazine and 3 M AMP has been used. The thermodynamic data and models developed in these projects have been useful for all the modelling activities in the projects. For the understanding of the water wash systems, it has been important to establish a dynamic model that describes the conditions in the water wash sections such that it is able to predict the outlet gas concentrations of amines also under transient conditions.

Keywords: Absorption, pilot plant, dynamic modelling, emission measurements

Authors: Thor Mejdell, Kai Hjarbo, Asmira Delic, Actor Chikukwa, Karol Michalski, Lars Hovdahl, Andreas Grimstvedt (SINTEF Industry).