Study Of Magnesia-based Catalytic Absorbent Desulfurization Denitrification

This cheap Magnesia from Dashiqiao in Liaoning was studied in order to get sorbent and catalyst, the desulphurization and denitrification of experiment was done using magnesia-based catalytic absorbent.This thesis summarizes existing desulphurization and denitrification processes and reviews the technological development. Several present oxide-desulphurization and denitrification techniques were compared. Feasibility and application foreground of magnesia in dry-desulphurization and denitrification were brought forward.In the study, the relationship between raw material mixture-ratio, technology condition of preparation process and magnesia-based catalytic absorbent characteristics was studied systematically and experimentally, and activation of the catalytic absorbent were studied. On the basis of the experiments, the technology process and optimum technology condition of preparing sorbent from magnesia were given. The optimum process condition were found through experiments as follow:75:15:10of the ratio of raw material mixture of magnesia, sodium silicate and sodium chloride, calcinations temperature550℃, calcinations time2h, activation effect were better. The surface turn to21.3982m2/g, but sulfur capacity were small about6.96mg/g. Because the sulfur capacity of sorbent were very importance. The absorption capability of sorbent were enhanced by adding Na2CO3. The sulfur capacity increases to16.92mg/g.In the study of desulphurization and denitrification, the experiments about desulphurization and denitrification process and influence factor were systemic researched, and the efficiency of desulphurization and denitrification was affected by some factors, such as oxygen content, steam content, coal smoke temperature. On the basis of desulphurization experiments. The results showed that O2/SO2=6～8, coal smoke temperature was120～150℃, H2O/O2=2～4, SO2concentration1500-3000mg/m3, layer height5-7cm.At this time, the desulphurization is above92%. Regarding denitrate processing, NO content500ppm～2000ppm; Experiment indicate oxygen had no effect on NOX removal rate, ascertain denitrification height of bed4-5cm, denitrification response temperature130～170℃, flue gas airspeed2500h-1-3000h-1, water vapour content of flue gas NO/H2O=10～20, efficiency of denitrification run up to85%～95%, denitrification effect stabilize, denitrification scope width.The method of heated alkali washing and vapor stripping were adopted in the regeneration experiments of sorbent. The result show when alkali wash time was60min, calcinations temperature550℃, calcinations time40min, the desulphurization effect are preferable. Sorbent utilization-ratio was effectively enhanced. The sulfur capacity only reduced9.43%after regenerative once.Desulphurization adsorption mechanism was analyzed. Physical adsorption and chemical adsorption occurred in this process in this. And a series of reaction when sulfur dioxide meeting magnesia were researched. Preliminary analysis catalyzer catalytic mechanism. Proven soft burning magnesia surface oxygen vice, is result in catalyzer possess active cause, whereas it was key that that of dead burnt magnesite surface magnesium vice, gotten thereof not possess catalytic activity, so develop out oxygen vice catalyzer. Denitrification effect stabilized.Experiment by dint of FT-IR make research on catalyst-sorbent from magnesia denitrification and regenerability, it show that denitrification or regeneration fore-and-aft catalyst-sorbent from magnesia catalyze property did not occur change, kept favorable stability, also account NO likely to translate into N2and O2. Experimental result indicate, catalyst-sorbent from magnesia, not only has higher efficiency of denitrification, with higher mechanical strength and lower cost, but also in a position to regeneration recycle, green avail environmental protection, and have good development prospects.