A novel process for CO2 capture from the flue gases to produce urea and ammonia

Abstract

The paper addresses the production of urea from carbon dioxide and nitrogen in the flue gas of the power plants as an alternative to other proposed and suggested processes. The conventional separation process of CO2 from flue gases has been so far directed to the methanol synthesis, while nitrogen, as the main part of the combustion product, is ignored. Carelessness about and lack of use of this byproduct is led to the techno-economical failure of the process and cause environmental problems. In this research, to the best of our knowledge, for the first time, the synthesis of urea and ammonia from the combustion of oxy-fuel was investigated and the appropriate and green process was designed and proposed. To enhance economic justification, the process design was carried out using all three main components of the flue gas (CO2, N2, and H2O), along with efficiency increment of the combustion units. Considering of 2036 kg/hr oxy-fuel combustion products, direct removal of 1700 kg/hr CO2 from the carbon cycle and production of 2856 kg/hr molten urea is estimated, which the latter product worth about 3.5 × 106 US$/year.