Regeneration of Fe–Zn–Cu Sorbents Supported on Activated Lignite Char for the Desulfurization of Coke Oven Gas

Abstract

In this paper, the regeneration characteristics of activated-char-supported Fe–Zn–Cu sorbents were studied. The desulfurization and regeneration experiments were carried out using a quartz fixed-bed reactor at ambient pressure. The effects of regeneration conditions, such as space velocity, temperature, and steam concentration, on the regeneration performance were examined. The crystal phase, chemical structure of activated components, and physical structure of sorbents before and after regeneration were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) surface area. The experimental results indicated that the char-supported Fe–Zn–Cu sorbents can be regenerated at temperatures above 500 °C. The optimal regeneration parameters with a space velocity of 5000 h–1, temperature of 700 °C, and steam concentration of 50 vol % have been obtained. The result of regeneration by steam suggested that the BET surface area of the sorbent after regeneration was larger than that of the fresh sorbent, and steam can restore the physical structure of the sorbent and expand its aperture during regeneration. Regeneration using SO2 was also studied under the optimal conditions. The XRD, FTIR spectroscopy, and XPS analyses indicated that the composite metal oxides in the sorbent formed during sulfidation were transformed into metal sulfides, which can be converted back to metal oxides during regeneration.

H2S removal from syngas using wastes pyrolysis chars

“…Usually, the conditions of char's production are adjusted in order to obtain materials with suitable properties [27]. Special modifications using chemicals, such as caustic impregnations or activation [28][29][30] and metal impregnation [21,22,[31][32][33][34] are carried out to enhance the activated carbon efficiency. However, these processes have high environmental footprint (use and management of chemicals), increase the cost of the materials and jeopardize their regeneration (low temperature of self-ignition) [35].…”

Removal of Hydrogen Sulfide and Ammonia by Goethite-Rich Limonite in the Coexistence of Coke Oven Gas Components

“…However, only a few studies have reported H 2 S removal in COG by iron-based adsorbents, such as iron oxide and/or iron-bearing sorbents combined with other metals. [24][25][26][27] It is well-known that a typical COG is composed of 54-59% H 2 , 24-28% CH 4 , 4-7% CO, 3-5% CO 2 , 1-3% CO 2 and 1-3% H 2 O with impurities, but the influence of the individual COG components on H 2 S removal has not been investigated in previous reports. [24][25][26][27] In this paper, therefore, we focus on investigating H 2 S removal and catalytic NH 3 decomposition performance using an Australian limonite in the presence of COG components to develop a novel gas cleaning method for removing H 2 S and NH 3 .…”

Pyrolysis of Low-Rank Coal: From Research to Practice

“…Moreover, the developed pore structure is also a typical character of chars derived from LRC pyrolysis. With further activation methods, chars can be served as adsorbing materials or catalyst supports [19][20][21]. Gas products, derived from LRC pyrolysis, are full of H 2 , CO and CH 4 , which are able to be fuels or chemical synthesis after purification.…”