Preparation of the lanthanum-doped iron-based composite desulfurizer and its desulfurizing performance at mid-temperature

The present paper aims to make clear the preparations of the lanthanum-doped iron-based composite desulfurizer and its desulfurizing performance at mid-temperature by taking the waste fly-ash from a power plant as a carrier. In our paper, we have managed to work out the efficient iron-based composite desulfurization agent doped with lanthanum with the method of homogeneous deposit, and investigated the specific surface area, density, yield,multiple desulfurization capacity and regeneration times of the carrier, along with the properties of desulfurizerXRD and SEMbefore and after desulfurization. The desulfurizer is known for its higher reactivity and higher sulfur capacity in relation to its developed pore and surface areas.The desulfurization performances were investigated in a fixed bed reactor. The effects of the carrier content, the molar ratio of La∶ Fe,the sulfidation temperature, calcination temperature and time were investigated atmedium-temperature.We have found that the desulfurizer has very high desulfurization activity with the fly ash added in at a ratio of 20% of the total mass of the desulfurizer. The other conditionsforpreparation can be stated asfollows: the molar ratio of La∶Fe should be kept about 1%, the time for calcinations is for 4 h at 500℃, and the desulfurization temperature should be kept at 400 ℃.The absorbents prepared should be able to undergo the testof four cycles of desulfurization-regeneration.After regenerating the desulfurizer four times, the accumulated saturated sulfur capacity should be made as high as 55.36%. In conclusion, it can be said that the composite desulfurizer for the mid-temperature gas clean-up enjoys nice properties of desulfurization and regeneration, which is by nature highly useful for the widely developing chemical industry in large industrial scales.