Development of an Analytical Method for Distinguishing Ammonium Bicarbonate from the Products of an Aqueous Ammonia Co2 Scrubber and the Characterization of Ammonium Bicarbonate

摘要

The link between anthropogenic emissions of CO2 with increased atmospheric CO2 levels and, in turn, with increased global temperature has been well established and accepted. Using aqueous ammonia to capture CO2 and produce an inexpensive nitrogen fertilizer, ammonium bicarbonate (ABC) has been thought as a feasible approach to CO2 sequestration.Due to the different concentrations of reactants and reaction conditions, different carbon-ammonium composites can be produced. In view of achieving a maximum of NH3 utilization in the capture of CO2, the product of ABC will be ideal. Hence the ABC in the products needs to be identified. Various analytical techniques were used to distinguish the ABC. FTIR, DSC, TGA and XRD techniques were used to qualitatively distinguish the ammonium bicarbonate from the ammonium salts. The carbon, hydrogen and nitrogen element analysis and Near Infrared (NIR) techniques were used as quantitative analysis of ABC. The AOTF-NIR Free Space spectrometer is an ideal tool for real-time, on-line measurements of ABC. Sample 01050401 and Sample 01060401 from the CO2 Scrubbing experiment by aqueous ammonia at WKU were determined by these techniques as ammonium bicarbonate and have very good quality as fertilizer in accordance with GB -3559-92 Agriculture Ammonium Bicarbonate National Standard of China.During fertilizer storage and application, an amount of ABC will decompose into NH3, H2O and CO2. Long-effect ABC (LEABC) is a product of co-crystallized dicyanodiamide (DCD) and ABC. In order to evaluate ABC fertilizer efficiency and its contribution to permanent carbon fixation, tests with Thermogravimetric Analysis (TGA) were conducted. The experiments by TGA indicated that the temperature and air flow rate have much less effect on the evaporation of the LEABC than on the ABC. Kinetic studies of ABC and LEABC gave their Activation Energy. At the 7.5% conversion rate, LEABC’s Activation Energy is 111.9 kJ/mole, which is greater than ABC’s Activation Energy 93.6 kJ/mole. The difference in Activation Energy explains the reason of different stability of ABC and LEABC.