Sustainability 2022 , 14 , 4669
3of 18
fluidized bed reactor (FBR) are analysed by Rivera et al. (2016) [11]. They obtain a syngas with a tar concentration of 11.44 g/Nm 3 and an LHV of 5 MJ/Nm 3 , considering a process temperature of 850 ◦ C and an ER of 0.3. An experimental campaign on co-gasification of WP–DIS pellets (consisting of 80% reject fibres and 20% mixed plastic by weight) with wood chips was carried out by Ouadi et al. (2013) [34]. Through 12 experimental tests, the authors identify optimum conditions: a blending ratio of WP–DIS pellets and wood chips of 80:20 by weight, a temperature of 1000 ◦ C, and an ER of 0.22. The generated syngas presents a tar concentration of 5.8 g/Nm 3 and an LHV of 7.3 MJ/Nm 3 . Identifying optimum operating parameters for biomass gasification through experi- mental campaigns is time-consuming and costly as several tests, in the range of 10 to 23, have to be performed [33–38]. Using computer-aided simulations of the biomass gasifica- tion process based on experimental outcomes can significantly reduce the time and cost of predicting the optimum operating parameters and process performances. As an example, Aspen Plus software allows identifying the conditions to improve the plant design, process limitations, or even failure conditions, which can improve the profit of an existing or proposed production plant [39]. The analysis of the literature highlights that no works are available on numerical modelling of gasification of WP and DIS except for an article where a mixture of used paper discarded as MSW is analysed [40]. In such a paper, Safarian et al. (2019) [40] develop a model to simulate the gasification of mixed-used paper and validate it by considering experimental outcomes related to the gasification of wood presented in the literature, founding an acceptable agreement. The authors identify the optimum operating temperature (1000 ◦ C) and ER (0.3) to maximize the concentration of H 2 and CO of syngas, which is characterized by an LHV of 4.62 MJ/Nm 3 . Regarding the process performance, they observe a CGE of 70.6%. Extending the literature review on biomass gasification highlights the significant inter- est of the scientific community in this topic. However, focusing on numerical simulation to assess the CHP generation potentiality of biomass through gasification integrated with an ICE, the available literature is limited [41–43]. Energy recovery from sewage sludge (SS) through gasification integrated with an ICE was assessed by Di Fraia et al. (2021) [41]. The authors develop a numerical model through the software Aspen Plus estimating the electrical (29.2%), thermal (45.92%), and cogeneration efficiencies (53.1%). The same biomass was analysed by Brachi et al. (2022) [42], which estimate electrical (19.3%) and thermal (48.7%) efficiencies for a similar energy recovery configuration. An integrated system composed of a gasifier and an ICE was investigated also by Villarini et al. (2019) [43], taking into account the energy valorisation of hazelnut shell and olive pruning, estimating an electrical efficiency of 30% and 26%, respectively, and a cogeneration efficiency of 64% and 41%. Based on average global pulp and paper industries’ energy demand data, the electrical and thermal energy required to produce paper from wood is estimated as 1.68 MWh/ton and 1.55 MWh/ton, respectively [1,44]. Energy recovery from WP and DIS through a gasifier integrated with an ICE could supply a fraction of the electrical and thermal energy demand for the paper production process. Therefore, in the present study, a numerical model is developed to assess the CHP generation potentiality of WP–DIS blends through gasification in combination with an ICE using Aspen Plus V8.8 software (Bedford, MA, USA), for the first time. The gasification model is developed by applying a restricted chem- ical equilibrium approach [24,41,42,45]. The model is calibrated against experimental data available in the literature related to the gasification of WP–DIS blends [11] and validated by considering the outcomes of an experimental campaign on bamboo chips gasification [46]. The developed model is used to predict the optimum operating parameters for gasification of WP–DIS pellets (made by mixing 85 wt% WP and 15 wt% DIS) by analysing the effect of process temperature and ER on syngas composition, process performances, and net power obtained from gasification products. Finally, electrical and thermal energy that could be generated by considering the proposed system to treat WP and DIS produced in the EU in
Made with FlippingBook - Online magazine maker