PAPER making! g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 9, Number 1, 2023
“ Ca 3 B 2 O 6 -modified papermaking white mud for CaCO3/CaO thermochemical energy storage ”, Caili Li et al, Chemical Engineering Journal , Vol.461, 2023. CaCO 3 /CaO thermochemical energy storage based on concentrated solar power plant is a promising technology because of its high working temperature and energy storage capacity. Papermaking white mud (PWM) from paper mill is a potential CaO-based precursor due to its high content of CaCO 3 . Herein, a novel Ca 3 B 2 O 6 -modified PWM was synthesized to examine its thermochemical energy storage performance. The influences of the types and dopant amounts of B2O3 precursors on the energy storage capacity of Ca 3 B 2 O 6 -modified PWM were discussed. The stable Ca 3 B 2 O 6 -modified PWM with the mass ratio of CaO to Ca 3 B 2 O 6 = 88:12 exhibits superior energy storage performance and heat transfer property during CaCO 3 /CaO cycles. The effective conversion and energy storage capacity of Ca 3 B 2 O 6 -modified PWM are approximately 0.67 and 2129.6 kJ/kg at 31st cycle, respectively, which are 2.48 and 1.76 times as high as those of PWM and pure CaCO 3 , respectively. The introduction of Ca 3 B 2 O 6 improves the sintering resistance and thermal conductivity of PWM, resulting in higher cyclic stability and lower decomposition temperature of CaCO 3 . Ca 3 B 2 O 6 enhances the basicity and improves the strong basic sites of PWM, which is beneficial for the adsorption of CO 2 , leading to greater CO 2 adsorption capacity. Moreover, Ca 3 B 2 O 6 increases the oxygen vacancy concentration of PWM, which is conducive to the diffusion of O 2 – and production of CO 3 2 – , further improving energy storage capacity. Hence, Ca 3 B 2 O 6 -modified PWM seems to be a suitable energy storage material for the CaCO 3 /CaO process. “Thermodynamic analysis of a cogeneration system in pulp and paper industry under singular and hybrid operating modes”, Ramadan Hefny Ali et al, Energy , Vol.263 Part E, 2023. In the present study, a thermodynamic analysis of a cogeneration system in a pulp and paper industry under different operating modes i.e., singular and hybrid with a variable ambient temperature is conducted according to actual operating data. For singular operating mode, the power boiler is only employed using natural gas while for hybrid operating mode, the power boiler with the recovery boiler is employed using natural gas and black liquor as main fuels, respectively. The results show that for hybrid operating mode in comparison with the singular one, the thermal efficiency of turbine and condenser is enhanced by 1.36 and 7.7%, respectively while it is reduced by 2.8% for the power boiler. In addition, the overall thermal efficiency under singular and hybrid operating modes is 87.4 and 53.7%, respectively. For hybrid operating mode, the exergy destruction of power boiler decreases by almost 10% compared with that for the singular operating mode. Also, at hybrid operating mode, the soda is recovered with a mass flow rate of 33 tons/hour that is required for the cooking process in the chemical pulp section and additionally the consumption of natural gas in the power boiler is reduced by 11.8%. “ Biological hydrogen production from paper mill effluent via dark fermentation in a packed bed biofilm reactor ” , Mahboubeh Namdarimonfared et al, Fuel , Vol.228, 2023. This study assessed the feasibility of continuous hydrogen production in an anaerobic packed bed biofilm reactor (APBR) using paper mill effluent (PME) without any pretreatment or modification. To form a microbial biofilm on supports, the reactor was seeded with a thermal pretreated anaerobic sludge. After the start-up stage, under mesophilic conditions and pH control, the system performance in the case of hydrogen production as biofuel and VFAs as valuable by-products as well as COD removal was investigated at different hydraulic retention times (HRTs) (24, 16, 12, 8, 4, 2 and 1.2 h). The highest hydrogen concentration in the produced gas was 41.5 % obtained at HRT 4 h. The highest hydrogen production rate and yield were 6.21 L H 2 d −1 L −1 at HRT 2 h and 0.96 mmol H 2 g −1 COD at HRT 8 h, respectively. With decreasing the HRT from 24 to 1.2 h, the OLR was increased
Technical Abstracts
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