Kinetic Behaviors of CaC₂ Production from Coke and CaO

Abstract

To replace the high-temperature and energy extensive traditional calcium carbide (CaC 2 ) production technique, characterized by electric arc heating and large granular feeds of coke and calcium oxide (CaO), methods using fine feeds with autothermal heating were reported to be promising at lower temperatures in the literature. To understand the kinetic behaviors of the low-temperature CaC 2 production, a series of experiments were carried out in a thermal gravimetric analyzer (TGA) coupled online with a mass spectrometer (MS). The results indicate that the initial temperature for the CaC 2 formation decreases linearly with an increase in contact points between the coke and CaO particles. The reaction proceeds differently in two temperature ranges, from 1550 to 1700 °C and from 1700 to 1750 °C. The rate-limiting step in the low-temperature range is mass transfer of solid CaO toward solid coke with an apparent activation energy of about 456 kJ mol −1 , while that in the hightemperature range is mass transfer of liquid CaO in the form of CaC 2 −CaO eutectics toward solid coke with a much lower apparent activation energy of about 256 kJ mol −1 . The direction of the mass transfer and the change in mass transfer mode were further confirmed by a number of special design experiments.

The role of different properties of activated carbon in CO2 adsorption

“…They were ground and sieved to 20-40 mesh, and then subjected to acid-washing with 10% HCl and 12% HF at 60°C for 24 h [16,17]. The treated ACs were washed with de-ionized water until pH reached 7 and dried at 150°C for 2 h. The resulting ACs were marked with (dA) after the usual code, such as coconut-AC(dA).…”

Calcium‐Based Sustainable Chemical Technologies for Total Carbon Recycling

“…Its characteristics depend considerably on the temperature. Significant mechanistic differences between ranges of 1550 to 1700 °C and 1700 to 1750 °C are evident . Different mechanisms of the reaction may alternate or be combined with pressure and temperature dynamics during the reaction …”

“…Significant mechanistic differen- ces between ranges of 1550 to 1700 8Ca nd 1700 to 1750 8C are evident. [46] Different mechanismso ft he reaction may alternate or be combined with pressure and temperature dynamics during the reaction. [47] The formal E factor for the synthesis of calcium carbidec an be calculated according to the reactionC aCO 3 (100 kg) + 4C (48 kg) = CaC 2 (64 kg) + 3CO( 84 kg).…”

Design of Oxy-Coal Reactors for Calcium Carbide Production Using CFD

“…Additional work presented by Li et al [27] focuses on the kinetic behavior of CaC 2 production derived from coke and CaO, including the effect of coke properties, such as crystalline structure and specific surface area, on the initial reaction temperature for CaC 2 production. The authors report a linear decrease in the dependence of the initial temperature with an increasing number of contact points between coke and CaO particles until the particle size is 0.06 mm, which corresponds to an initial temperature of 1440 °C.…”

“…This is achieved by solving the Radiative Transfer Equation (RTE) for a participating media in which the effect of absorption, emission and scattering is considered. This equation was solved using the P-1 radiation model and the discrete ordinates (OD) radiation model (Howell, Siegel, & Pinar [43]), which can account for the effect of radiation exchange between the gas and particle phases as well as for scattering 27 . Both models were tested for oxy coal combustion in the exploratory study completed for this project [111].…”