Sustainability 2022 , 14 , 4669
4of 18
2019 is assessed, together with the achievable reduction of CO 2 emissions compared to the use of conventional fuels. Therefore, the present article presents a sustainable and energy-efficient solution for the paper and pulp industry. Indeed, CHP from WP and DIS may contribute to: - reduce the waste landfilling; - increase the energy dependence of the paper and pulp industry; - at the global level, increase renewable energy generation and reduce GHGs. The paper is organized as follows. The numerical model developed together with modelling assumptions is described in Section 2. The input parameters of the analysed case study and the main results of the study, including those of the sensitivity analyses, are illustrated in Section 3. Finally, the main findings and future developments of the work are presented in Section 4. 2. Materials and Methods Energy recovery as CHP from WP and DIS generated during recycling of pulp from used paper through gasification integrated with an ICE is numerically analysed. The numerical model proposed in this work is calibrated against experimental data on syngas generation from WP–DIS pellets consisting of 95 wt% WP and 5 wt% DIS in a pilot-scale FBR, characterized by 300 mm reactor diameter, 8764 mm height, and recircu- lation pipe diameter 127 mm where gasifying agent air completes the fluidization of the bed [11]. After calibration, the model is validated against the experimental outcomes of bamboo chips gasification in a laboratory scale fixed bed gasifier with 100 mm diameter and 1400 mm height [47]. Two distinct WP–DIS pellets are considered in the analysis, from now on M1 (95% WP and 5% DIS by weight) and M2 (85% WP and 15% DIS by weight). The detailed experimental procedure for WP and DIS collection, sample pel- lets preparation, and characterization as well as details on the experimental campaign, are available in the literature [11]. The numerical model to simulate the conversion of WP–DIS blends to CHP is devel- oped in Aspen Plus V8.8. The software library does not have a unique block for either the gasification process or the ICE. Thus, gasification is modelled considering the processes from which it is composed: drying, pyrolysis, gasification, and partial combustion to transform the energy content present in the WP–DIS pellet to syngas [22,48]. As commonly proposed in the available literature, the ICE is simulated by considering four consecutive blocks, a compressor followed by a chemical reactor to complete the combustion at constant volume, a turbine, and finally, a heat exchanger for cooling at constant volume [41,43,49,50]. The process flowsheet to simulate the CHP generation from WP–DIS pellets is pre- sented in Figure 1.
Figure1. Flowsheet related to the simulation on CHP generation from WP–DIS pellets.
Made with FlippingBook - Online magazine maker