CO2 Utilization with Desalination Reject Brine

  • Abdallah Dindi

Student thesis: Master's Thesis

Abstract

One of the factors militating against the deployment of CO2 Post Combustion Capture (PCC) is its high costs of operation. It has been opined that the utilization of CO2 for industrial applications has the potential to provide a moderate revenue stream to support the demonstration phase of CCS projects in the near term. As Gulf countries begin to embrace CCS in the bid to reduce their high per capita CO2 emissions, it is important to consider CO2 utilization opportunities offered by another environmental problem which is the highly concentrated brine waste coming from desalination plants. This study evaluated the feasibility of a chemical process which uses desalination brine to convert CO2 into useful commercial products. The process is based on the integration of a modified Solvay process with conventional PCC for the simultaneous capture and conversion of CO2 into solid bicarbonates. The benefit of this kind of concept lies in its potential to mitigate harm from two waste products as well as reduce the costs CO2 capture through the generation of a product which can be sold to offset some of the capture costs. The CO2 utilization potential of reject brine produced in the UAE was evaluated and a range of amine solvents were screened to select the most suitable for the process. The effects of parameters such as temperature, brine concentration and amine concentration on the performance of the process were also evaluated. Because the amine needs to be recycled in the process to save costs and prevent its discharge into the environment, different techniques for recovering the amine from its chloride salt formed during the absorption step were investigated. The results showed that saleable sodium bicarbonate can be obtained when Flue gas is brought in contact with reject brine and this has the potential to reduce over 30% annual CO2 emissions of the UAE. In addition, sterically hindered amines such as 2-amino, 2-methyl propanol were found to be the best alcohol amines for the process. While the amine recovery needs to be optimized, process performance was significantly improved at lower temperatures and higher brine concentrations while amine concentration needs to be maintained at an optimum of 30 weight%.
Date of Award2014
Original languageAmerican English
SupervisorMohammad Abu Zahra (Supervisor)

Keywords

  • Carbon Dioxide Mitigation; CO2 Emissions; Desalination.

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