SEPPIL (NO2.4)

Purpose and brief technical description, including figures as appropriate

SEPPIL / CCCP is a lab-pilot experimental facility suitable for CO2 separation and purification of gas mixtures originating from pre-combustion applications such as hydrogen production, oxy-fuel processes, and pre-separated flue gases from post-combustion applications in industry and power generation.  

The main purpose of the rig is to demonstrate the capture efficiency (CO2 capture ratio) from various types of above-mentioned relevant gas mixtures by cooling and condensation, in addition to liquefaction of CO2. This has been demonstrated in operational modes (finite separator retention time) and in a scale sufficiently large for industrial interest in four different projects so far. The throughput capacity is approximately 340 Sm3/h, which gives a CO2 throughput rate in the rough interval 5–15 ton per day, depending on the exact gas composition in consideration. 

CO2-rich liquid is separated from CO2-depleted gas in two separator tanks in series. The bulk separation takes place at high pressure in the first of the two vessels. At the inlet of the second vessel the liquid is throttled to lower pressure, which increases the purity of the liquid CO2. 

The test rig is instrumented to monitor the operation of heat exchangers, separators, compressors and other auxiliary systems: 15–20 temperature sensors (excluding compressor instrumentation); 6 pressure transmitters (excluding compressor instrumentation); 2 level meters for separation tanks; 4 mass flow meters; 5 extraction points for composition measurement by gas chromatography. Maximum operation pressure is 120 bar on the high-pressure side. 

An auxiliary refrigeration cycle with CO2 as refrigerant is included in the RI. This unit has an evaporator temperature of around -50 °C. The capacity of the refrigeration unit is approximately 7.5 kW. 

General: Located in the thermal laboratories of NTNU with its available infrastructures and services. 

Special: See brief instrumentation description above. Available gases: CO2, nitrogen, hydrogen, CO, methane

The RI is the first of its kind with the given process design. 

The RI fits very well with the national R&D priorities on CCS. Specifically, the CLIMIT strategy and program plan calls for multiple CCS technologies for CO2 capture to reduce costs and energy use. Further, CLIMIT calls for efficient ship transport, in which low-temperature separation processes are attractive, since additional liquefaction can be avoided. 

With the growing focus on hydrogen production from natural gas, the RI has also been successfully used to investigate separation of syngas-derived tailgas mixtures for CO2 capture, which  is a promising processing step in combination with hydrogen-selective separation processes such as membranes and pressure-swing adsorption.