Process design for CO2 absorption from syngas using physical solvent DMEPEG

Pre-combustion IGCC is one of the leading technologies having potential for effective control of green-house gas emission. Process design for CO2Capture from power plant is becoming increasingly importantin the past decades in view of the need for optimization of Capital Cost and Utility consumption. Inthis article, a configuration of the process design for CO2absorption using physical solvent DMEPEG isproposed, which is described using the process flow diagram (PFD) and the Flowsheet. CO2absorptionperformance of DMEPEG solvent is assessed based on a rate based mass transfer model using ProTreat®simulation software. The rate based mass transfer simulation by ProTreat software adds to the reliabilityof the simulation result (as evident by its acceptance within industry). The trade-off between H2recovery(by syngas recycle) and CO2re-absorption is described which reveals that more than 55% H2recoverymay significantly increase the load on the system (in terms of syngas processing and CO2re-absorption).Objective of this research is to develop a detailed process model for CO2absorption by DMEPEG solvent(to enable detailed techno-economic assessment by bottom up approach). In the second section of thisarticle, the process of CO2capture by physical solvent DMEPEG is explained. In the fourth section, theboundary conditions such as the inlet pressure, temperature and composition of syngas and solvent feedare defined. In the fourth and fifth section, the design and performance of the packed tower is describedand the utility consumption is estimated. Moreover, the outlet condition of the solvent is described andits saturation (by CO2) is estimated. In the fourth section, the strategy of solvent heating to recycle thesyngas to CO2absorber (for H2recovery) is described. Importance of CO2 absorption in solvent (at highconcentration) for minimization of equipment size and utility consumption for CO2 capture is explained. Using RSR packing (6.4 m Dia., 16 m Ht. (9 + 6 + 1)) results in 90.7% CO2absorption and 89% saturationof CO2dissolved in DMEPEG solvent. Out of 3.34 kmol/s H2fed to the CO2Absorber (as part of syngas),1.464% (equivalent 5.9 MW power generation by Gas Turbine in open cycle) is co-absorbed (along withCO2) in DMEPEG solvent. Out of this co-absorbed H2, 55.7% is recovered which is equivalent to 3.267 MWPower Generation.In terms of hydraulic design, the CO2 Absorber using RSR packing operating at 72.5% flood conditionresults in packing pressure drop of 87.5 Pa/m (1.4 kPa). Packed section diameter and height is suggestedfor various random packing materials (tower internal) to achieve almost comparable gas absorption performance.