Uncertainties in assessing the environmental impact of amine emissions from a CO<sub>2</sub> capture plant

Abstract

Abstract. In this study, a new model framework that couples the atmospheric chemistry transport model system Weather Research and Forecasting–European Monitoring and Evaluation Programme (WRF-EMEP) and the multimedia fugacity level III model was used to assess the environmental impact of in-air amine emissions from post-combustion carbon dioxide capture. The modelling framework was applied to a typical carbon capture plant artificially placed at Mongstad, on the west coast of Norway. The study region is characterized by high precipitation amounts, relatively few sunshine hours, predominantly westerly winds from the North Atlantic and complex topography. Mongstad can be considered as moderately polluted due to refinery activities. WRF-EMEP enables a detailed treatment of amine chemistry in addition to atmospheric transport and deposition. Deposition fluxes of WRF-EMEP simulations were used as input to the fugacity model in order to derive concentrations of nitramines and nitrosamine in lake water. Predicted concentrations of nitramines and nitrosamines in ground-level air and drinking water were found to be highly sensitive to the description of amine chemistry, especially of the night-time chemistry with the nitrate (NO3) radical. Sensitivity analysis of the fugacity model indicates that catchment characteristics and chemical degradation rates in soil and water are among the important factors controlling the fate of these compounds in lake water. The study shows that realistic emission of commonly used amines result in levels of the sum of nitrosamines and nitramines in ground-level air (0.6–10 pg m−3) and drinking water (0.04–0.25 ng L−1) below the current safety guideline for human health that is enforced by the Norwegian Environment Agency. The modelling framework developed in this study can be used to evaluate possible environmental impacts of emissions of amines from post-combustion capture in other regions of the world.

Modelling atmospheric oxidation of 2-aminoethanol (MEA) emitted from post-combustion capture using WRF–Chem

“…Heikkilä et al (201 0) showed that regional climate simulations for the time period with the WRF model driven by the ERA-40 reanalysis better resolved the orographic lifting with 10-km horizontal resolution than with 30-km horizontal resolution. Karl et al (2014) analysed precipitation 1 elsevier_STOTEN_17722 data for 2007 at 14 meteorological stations in the region of Bergen, concluding that the WRF model, using identical configurations and meteorological boundaries as in the present study, underestimated the observed precipitation amount on a weekly basis at most stations by up to a factor of two. However, the weekly pattern of observed precipitation was well reproduced.…”

“…The reactivity of MEA in the study region was overall higher in the WRF--Chem simulations than predicted by the WRF--EMEP model framework presented in Karl et al (2014). However, due to lower NO x levels in WRF--Chem, the average production yield of MEA-nitramine in the reaction between MEA and OH was only 0.1%, a factor of 9 lower than in WRF--EMEP.…”

“…A detailed evaluation of the WRF model using ECMWF reanalysis meteorological data for ICs and BCs including five local weather monitoring stations (Bergen, Fedje, Flesland, Takle, and Kvamskogen) in the region of Bergen has been performed in the study by Karl et al (2014), and satisfactory agreement with the observed hourly data on 2 m-temperature and frequencies of wind direction and wind speed was found. The WRF model reproduced the west-east gradient of the annual precipitation amount, which is due to the orographic rainfall when humid Atlantic air masses meet the hill chain in about 20 km distance to the east of Mongstad.…”

“…The system is similar to the EMEP4UK modelling system (Vieno et al, 2010) which is designed for scientific and policy studies in the UK at 5-km horizontal resolution. A detailed description of the configuration of NILU''s WRF--EMEP model system is given in Karl et al (2014). WRF--EMEP applies a one-way nested procedure with separate runs for the different nests, beginning with the coarsest horizontal resolution of 50 km (EMEP standard domain covering all of Europe), an intermediate domain with 10-km resolution and an inner domain with 2-km resolution covering the west coast of middle Norway (200 × 200 km 2 ); similar to the WRF--Chem inner domain.…”

“…Two different MEA oxidation schemes were included in this study: (1) a simplified scheme, referred to as MEA-Simple described in Karl et al (2014), and (2) a more detailed scheme, referred to as MEA-Detail, developed by Karl et al (2012) which includes the most relevant reaction paths of the OH-initiated MEA oxidation. The MEA-Detail scheme includes 17 reactions and 17 species.…”