Potential Dynamics of CO2 Stream Composition and Mass Flow Rates in CCS Clusters

Sven-Lasse Kahlke,Heike Rütters,Alfons Kather,Martin Pumpa,Stefan Schütz

doi:10.3390/pr8091188

Abstract

Temporal variations in CO2 stream composition and mass flow rates may occur in a CO2 transport network, as well as further downstream when CO2 streams of different compositions and temporally variable mass flow rates are fed in. To assess the potential impacts of such variations on CO2 transport, injection, and storage, their characteristics must be known. We investigated variation characteristics in a scenario of a regional CO2 emitter cluster of seven fossil-fired power plants and four industrial plants that feed captured CO2 streams into a pipeline network. Variations of CO2 stream composition and mass flow rates in the pipelines were simulated using a network analysis tool. In addition, the potential effects of changes in the energy mix on resulting mass flow rates and CO2 stream compositions were investigated for two energy mix scenarios that consider higher shares of renewable energy sources or a replacement of lignite by hard coal and natural gas. While resulting maximum mass flow rates in the trunk line were similar in all considered scenarios, minimum flow rates and pipeline capacity utilisation differed substantially between them. Variations in CO2 stream composition followed the power plants’ operational load patterns resulting e.g., in stronger composition variations in case of higher renewable energy production.

Highlights

Capturing CO2 at large stationary point sources such as industrial plants or power stations and storing it in deep geological formations is one technological option to reduce anthropogenic CO2 emissions (e.g., [1,2,3])
Modelled net efficiency curves of the power plants with CO2 capture are depicted in Figure 2 as a function of the relative thermal input
Regarding the oxyfuel power plants, a less steady course of the net efficiency curve is apparent (Figure 2) as one or two compressor trains may be deactivated at 75% and 50% load, respectively, in case of an installation of a four-part flue gas compressor, which results in a significant reduction of power consumption

Summary

Introduction

Capturing CO2 at large stationary point sources such as industrial plants or power stations and storing it in deep geological formations (so-called CCS technology) is one technological option to reduce anthropogenic CO2 emissions (e.g., [1,2,3]). The term “CO2 streams” is used for streams from CO2 capture processes that consist of CO2 and impurities (cf [6,7]). According to Directive 2009/31/EC [6], CO2 transport pipelines “should be designed so as to facilitate access of CO2 streams meeting reasonable minimum composition thresholds”. It is not yet known how such composition thresholds may be defined and which CO2 qualities may be viable in practical application when CO2 streams with larger quantities and various types of impurities are considered.

Methods

Results

Discussion

Conclusion