It can easily be reconfigured for studying split flow applications, advanced heat integration and similar interesting CO2 capture optimization scenarios.
The mini-pilot consists of an absorber and a stripper unit (see figure 1). The absorber (A) and the stripper (F) are constructed, as modular-based stainless steel columns, making it possible to extend the heights for future application. The absorber has 7 packed sections and the desorber has 4. Each module is 19.8 cm high and the inner diameter is 49.75 mm.
The absorber has on every second flange a sample outlet (B) while on every other flange it has a liquid inlet (C). In total it has three lean solvent inlets, given the option to feed lean solvent at different heights, and four sample outlets. Solvent is distributed into the column with a sprinkler consisting of four holes with a diameter of 1 mm. Gas is introduced to the absorber in the bottom. The setup is equipped with solvent recycle. CO2 concentration is measured at the absorber in- (I) and outlet (J).
The stripper was originally designed and constructed by Lejre and Fjellerup [1]. The stripper has on every flange a liquid inlet – in total three liquid inlets. Beneath the column is a reboiler (G), which can heat up to 140°C. The CO2 gas stream leaving the stripper at the top enters the condenser (H) in the bottom. The condenser consist of a 1.5 m long coiled tube with cold tap water inside. The gas moves upward leaving the condenser in the top. Condensate leaves by the bottom. The purified CO2 gas recycles to the absorber. The condensate is pumped to the hot lean solvent stream. The plant can be operated up to 3 bar.
The mini-pilot features a main heat exchanger (K) and one additional exchanger (L) for cooling down the lean solvent stream before entering the absorber.
Solvent is introduced to the system via a funnel (D) and led into a storage tank (E) beneath the absorber. The solvent is pumped around the system using a piston pump (M).
Currently, solvents as monoethanolamine (MEA), and MEA with vapour reducing additives (VRA) are tested on the mini-pilot. The aim is to study the impact of VRA on the CO2 capture process.
[1] Kasper H. Lejre, Kasper Fjellerup, Design, Construction and Operation of a laboratory scale desorber unit for investigating desorption processes in post-combustion CO2 capture, BSc. Thesis, DTU 2013