Comprehensive analysis of pipeline transportation systems for CO2 sequestration. Thermodynamics and safety problems

The aim of this paper is to analyze CO2 compression and transportation processes with safety issues for post-combustion CO2 capture applications for basic technological concepts of a 900 MW pulverized coal-fired power plant. Four various types of compressors including a conventional multistage centrifugal compressor, an integrally geared centrifugal compressor, a supersonic shock wave compressor, and pump machines were used. This study emphasizes that total compression power is a strong function of the thermodynamic process and is not only determined by the compressor efficiency. The compressor increases the CO2 pressure from normal pressure to critical pressure and the boosting pump continues to increase the pressure to the required pressure for the pipeline inlet. Another problem analyzed in this study is the transport of CO2 by pipeline from the compressor outlet site to the disposal site under heat transfer conditions. Simulations were made to determine maximum safe pipeline distance to subsequent booster stations depending on inlet pressure, environmental temperature, the thermal insulation thickness and the ground level heat transfer conditions. From the point of view of environmental protection, the most important problem is to identify the hazards which indirectly affect CO2 transportation in a strict and reliable manner. This identification is essential for effective hazard management. A failure of pipelines is usually caused by corrosion, material defects, ground movement or third party interference. After the rupture of the pipeline transporting liquid CO2, a large pressure drop will occur. The pressure will continue to fall until the liquid becomes a mixture of saturated vapour/liquid. In the vicinity of the rupture, liquid CO2 will escape and immediately vaporize and expand. In the paper the discharge and atmospheric dispersion of CO2 are discussed.