Research On Regeneration Process Of Zn-Mn-Cu Based Sorbents Loaded On Semi-Coke

The poly-generation technology based coal gasification is now considered as an important way to solve the problem of energy supply and environmental pollution. However, the release of hydrogen sulfide in gasification will bring serious disadvantages. Moreover, the heating and cooling of gas disease caused by industrialized technology of normal and low temperature desulfurization leads to the loss of calories in gas. As a result, the desulfurization of gas under condition of medium and high temperature is one of the key technologies which should be investigated and explored during clean coal conversion process.Semi-coke, as a cheap and easy-getting carrier, was selected to prepare Zn-Mn-Cu based sorbents by high-pressure impregnation method. The sorbents have the advantages of good desulfurization performance, high sulfur capacity, excellent mechanical stability. However, The issue of regeneration reaction of sorbent after desulfurization restricts the further application due to the special nature of the carbon-based carrier.Zn-Mn-Cu based sorbents loaded on semi-coke was selected as researching object in this paper. The changes of the active ingredient and carrier were investigated in the desulfurization process.The influence of regeneration conditions such as temperature, atmosphere and time on regeneration performance during reaction were also studied. The crystal form and valence distribution of active component and the pore parameters and structure of carriers were characterized by XRD, XPS, N2adsorption, and Raman spectroscopy, in order to determine the optimum conditions, and apply the optimum conditions to desulfurization and regeneration cycle test of adsorbent.The main conclusions are as follows:(1) The micropore volume of sorbent after desulfurization decreases and the most probable pore size increases evidently, which indicate that the reaction of desulfurization mainly occur in the micropore of sorbent. Therefore, abundant pore structure should be improved in the regeneration process. Metal active component exist in the form of metal sulfide after desulfurization process, and thus metal sulfide should be transform to metal oxidation in the regeneration reaction.(2) The optimal conditions of regeneration reaction are obtained with atmosphere of10%H2O、0.5%NH3and0.5%O2, temperature of500℃and time of3h. The addition of NH3can evidently decrease the loss of semi-coke which declines the weight loss ratio of sorbents. The regeneration temperature of500℃and time of3h can restore the pore structure and active component and will not cause the destruction of semi-coke structure and amount loss of carrier.(3) In the desulfurization and regeneration cycle test, the breakthrough sulfur capacity can reach78%of that of fresh sorbents when sulfured sorbent went though the regeneration process under optimal conditions. Better desulfurization capacity remains and the breakthrough time is more than165minutes (content of exit H2S<15ppm) when sulfured sorbent undergo two regeneration progress. As a whole, there is higher efficiency of the desulfurization and regeneration cycle test under the optimal conditions for regeneration.