The Study Of CO₂Capture System In Natural Gas Power Plant Based On MEA

ABSTRACT:The increasing anthropogenic carbon dioxide (CO2) emission threatens to change the earth’s climate. A major reason of global warming is CO2emission from power plants. In China, coal-fired generation’s high proportion and serious pollution problems need to be solved. Nature gas has many advantages such as clean, reliable, flexible and safe, however. Development of China’s natural gas generation is very necessary and urgent.One way of decreasing CO2emissions is CO2capture and separation (CCS) Among all different post-combustion capture processes of CO2, chemical absorption process was considered as an optimum one because of low CO2concentration in flue gas. Chemical absorption of CO2in simulated flue gas from natural gas power plant with aqueous monoethanolamine (MEA) solution was investigated. This paper optimizes the operation condition of CO2dynamic capture device and explores the influence of the concentration of O2in the flue gas, and analysis the degradation of MEA solution and corrosion of equipment pipeline, screening for appropriate antidegradant and corrosion inhibitor. Get the following results and conclusions:1) In order to make the CO2dynamic experimental device can be used in optimum operating condition, under the same MEA concentration, absorption temperature and regeneration temperature,the tests were conducted over the liquid/gas ratio are from16L/m3to4L/m3,absorption and regeneration performance of CO2capture system were analysed by experiment method.lt shows that, in the other condition same situation, the absorption and regeneration performance of CO2capture system have achieved good effect at the liquid/gas ratio is16L/m3. The CO2removal rate can maintain21h at more than80%, and CO2regeneration rate eventually stabilized at around70%.2) Under the same liquid/gas ratio, absorption temperature and regeneration temperature,the tests were conducted over MEA concentration from10%to40%, absorption and regeneration performance of CO2capture system were analysed by experiment method.It shows that, in the other condition same situation, the absorption and regeneration performance of CO2capture system have achieved good effect at the MEA concentration is30%. The CO2removal rate can maintain28h at more than80%, and CO2regeneration rate eventually stabilized at around70%.3) This paper also analyzes the diffientO2concentration in simulated flue gas (0%,6%,10%and14%) effect on the absorption and regeneration performance of CO2capture system.The result shows that, mass fraction of30%MEA solution was degraded in the presence of10%oxygen, the degradation rate of about11%, resulting in a certain amount of solution loss. Sodium metavanadate, ascorbic acid and sodium sulfite are antioxidants can be used in MEA solution. The addition of a small amount(0.1%) of sodium metavanadate or sodium sulfite can improve the performance of the MEA solution in respect of anti-degradation. The antioxidant properties was observed to decrease in the order sodium metavanadate> sodium sulfite> ascorbic acid.4) Stainless steel SS316L corrosion can be effectively inhibited by adding a small amount of an oxide film corrosion inhibitor(sodium Metavanadat, otassium dichromat and WHL-404) to the MEA solution. The experiments showed that when sodium Metavanadat (0.1%) were added, corrosion by MEA solution was significantly inhibited and SS316L were protected effectively against corrosion, The corrosion inhibition efficiency was over90%, with the corrosion rate being reduced from1.28g·m-2·h-1to as low as0.09g·m-2·h-1. The corrosion inhibition efficiency was observed to decrease in the order sodium metavanadate> otassium dichromat> WHL-404.5) In this study, the formation process of film formed by MEA solution and corrosion on the surfaces of SS316L were studied by scanning electron microscopy (SEM) and energy dispersivespectroscopy (EDS). The results showed that the surfaces of stainless steels was relation to the content of some composition of the stainless steels. With the increase of immersion time, matrix metal elements of the stainless steel, such as Fe, Cr and Ni, are reduced with different degrees, but C and O are incrased. All of corrosion begin with pitting, then the respective corrosion points connect into the lines, and eventually form a large area corrosion.