Chemical-looping combustion and chemical-looping with oxygen uncoupling of kerosene with Mn- and Cu-based oxygen carriers in a circulating fluidized-bed 300W laboratory reactor

Abstract

The fuel conversion properties of two oxygen carriers, based on manganese-and copper-oxide, were investigated with sulphur-free kerosene in a chemical-looping reactor with continuous particle circulation. An injection system was used, in which kerosene was evaporated, mixed with superheated steam and fed directly into the lab scale chemical-looping reactor. The manganese-based oxygen carrier M4MZ-1200 was composed of 40 wt% Mn 3 O 4 and 60 wt% MgO-ZrO 2 and was used for chemical-looping combustion (CLC) experiments for 17 h. The copper-based oxygen carrier C2Z-1050 was composed of 20 wt% CuO and 80 wt% ZrO 2 and was used for 45 h with fuel addition. With M4MZ-1200 oxygen carrier, 83 -99.3 % of the fuel carbon was converted to CO 2 at temperatures between 800°C and 950°C and fuel flows equivalent to 144 -462 W th . Higher conversions at lower temperatures than with M4MZ-1200 were achieved with C2Z-1050, which is likely due to the ability of CuO to release gas phase oxygen in the fuel reactor, i.e. CLOU properties. Here, 99.99 % CO 2 yield was achieved at 900°C and 144 W th fuel equivalent. The particles were analyzed before and after the experiments using XRD, SEM, BET surface area and particle size distribution. Whereas nearly the whole batch of M4MZ-1200 particles was disintegrated after the experiments, only about 5 % of the C2Z-1050 particles turned to fines. This is the first time that combustion of liquid fuel using CLOU is demonstrated in a continuous unit.

Materials for Chemical-Looping with Oxygen Uncoupling

“…Experimental results from continuous units are promising. All data from continuous units with these types of fuels report very high or complete conversion of the fuel to CO 2 and H 2 O [31,75,114,124].…”

“…The technology has been successfully demonstrated in a number of continuous units utilizing Fe- [28,29], Mn- [30,31], Cu- [32], and Ni-based oxygen carriers [33][34][35][36][37]. There are a number of recent reviews available on the status of CLC, whereof the more recent ones by Fan [38], Lyngfelt [39], and Adanez et al [40].…”

“…There are only a limited number of studies focusing on utilizing liquid fuels, such as oil, with chemical-looping technologies [31,[46][47][48][49]. Of these, only two investigations have been performed where the fuel is directly injected into a circulating CLC system [31,49].…”

“…Of these, only two investigations have been performed where the fuel is directly injected into a circulating CLC system [31,49]. Here kerosene was utilized as fuel and was evaporated prior to injection into the fuel reactor.…”

“…Adanez-Rubio et al tested four types of solid fuels in a continuous CLOU unit and from the analysis it was found that between 45 and 490 kg/MW material was needed in the fuel reactor in order to achieve 95% carbon capture [96]. Moldenhauer et al [31] investigated the combustion of kerosene utilizing CLOU and a CuO/ZrO 2 oxygen carrier in a circulating CLOU unit. The fuel conversion to CO 2 and H 2 O was between 95% and 99.99% in the temperature range of 750-900 ∘ C. These results were obtained using a total solids inventory (air reactor + fuel reactor + particle locks) corresponding to 2000 kg/MW.…”