• Energy Research

The recovery of energy from organic waste opens a chance to promote the renewable energy production, reducing the use of fossil-based fuels. This study is focused on the virtuous valorization of swine manure, which is conventionally used as a fertilizer. An integrated valorization process of swine manure via transesterification and CO 2 -assisted pyrolysis was suggested to maximize the recovery of energy-intensive and value-added products, such as biodiesel, biochar, and syngas. Lipid fraction in the swine manure was transformed into biodiesel through thermally induced transesterification. The yield of biodiesel was ≥94 wt % (based on the lipid content) in the existence of silica and swine manure biochar at 400 and 220 °C, respectively. The biochar acted as a porous medium and alkaline catalyst for transesterification. The residual solid after transesterification ( i.e., lipid-extracted swine manure) was valorized with pyrolysis. CO 2 was fed as a co-reactant to carry out the process in a more sustainable manner. In the presence of CO 2 , the enhancement of CO production was observed because of the homogeneous reactions of CO 2 with gaseous pyrogenic products derived from swine manure, compared to pyrolysis in a N 2 atmosphere. To expedite the reaction rates affecting the homogeneous reaction, a Ni/SiO 2 catalyst was adopted. Syngas formations were significantly enhanced through the synergistic effects of CO 2 and the Ni/SiO 2 catalyst. All experimental observations signified that swine manure could be considered a useful resource that can be valorized into value-added fuels and chemicals.

Green hydrogen has been proposed as a clean and sustainable source of energy with unrivaled potential to play a pivotal role in every country's transition toward a low-carbon economy while striving to achieve Sustainable Development Goals. Herein, we provide perspective of using green hydrogen to enhance the sustainability in Pakistan. As renewable energy resources (e.g. solar and wind power) are abundantly available in Pakistan, the production of green hydrogen linked to renewable energy resources is conscious. As a representative case, the green hydrogen project in Sindh, Pakistan was announced—hydrogen is produced by water electrolysis powered by renewable electricity generated from solar or wind power. The potential of a circular economic approach to green hydrogen production in Pakistan is discussed in terms of policy development, public and private participation, public demand, and public awareness. Green hydrogen is indeed the green light of the future for Pakistan, as it can potentially help boost its economy while mitigating climate change. The insights given by this study can be useful to further develop any future green hydrogen roadmap for Pakistan.

In this study, we analyzed the effect of dispersant characteristics on the selective catalytic reduction (SCR) catalyst properties and de-NOx efficiency. For this, we measured the zeta potential and pH value of each dispersant, and compared the thermal properties of the dispersant through TG-DTA analysis. Also, the Py-GC/MS analysis results and the MSDS contents of the product were used to compare the components and molecular weight types of the dispersant. As a result, the higher the zeta potential, pH, and molecular weight of the dispersant, the more improved the dispersibility of the TiO2 slurry. Characteristics such as the rheology, sedimentation, and pH change, were studied to compare the dispersibility of the catalyst slurries, and the dispersion characteristics of the TiO2 slurries were confirmed by TEM. The SCR catalysts prepared varied based on the dispersant added, with the varying factor being the de-NOx efficiency between (250 to 450) °C depending on the dispersibility. The dispersant with the excellent dispersibility gave the highest efficiency of 84% or more at 250°C and 300°C, and the highest de-NOx efficiency of more than 92% at 350°C and 400°C.

In this study, the optimal capacity of a battery and power conditioning system (PCS) of energy storage system were calculated. In addition, economic analysis was conducted to determine the optimal equipment standard, taking the government support plan into account. In addition, the changes in the power generation pattern were examined when the energy storage system and photovoltaic (PV) were connected to verify the power peak management efficiency of the energy storage system. Moreover, the effect of the energy storage system support policy was assessed by comparing the economic efficiency of single-PV equipment and energy storage system-connected equipment by the internal rate of return. Internal rate of return was analyzed by the change in cost of energy storage system equipment and the price of system marginal price/renewable energy certificate, which was a sales factor, and used for economic forecasting of the energy storage system. To accomplish this, the 2015 power generation output data (daily average 3.69 h power generation) of LG Hausys Ulsan station were converted to small-scale (3 MW) and large-scale (10 MW) solar power and a model that calculated the factor capacity of battery and the PCS capacity of the energy storage system was then constructed. Furthermore, the selected battery capacity and PCS capacity were analyzed separately by economic analysis to propose an energy storage system equipment standard, which could guarantee the optimal economic efficiency. Finally, based on the “Guideline for Management and Operation of Mandatory Supply for New and Renewable Energy” established by the Ministry of Commerce Industry and Energy, the profit model applied to the economic analysis was limited to an energy storage system charged from 10:00 to 16:00.

In this study, wasted mask is chosen as a pyrolysis feedstock whose generation has incredibly increased these days due to COVID-19. We suggest a way to produce value-added chemicals (e.g., aromatic compounds) from the mask with high amounts through catalytic fast pyrolysis (CFP). To this end, the effects of zeolite catalyst properties on the upgradation efficiency of pyrolytic products produced from pyrolysis of wasted mask were investigated. The compositions and yields of pyrolytic gases and oils were characterized as functions of pyrolysis temperature and the type of zeolite catalyst (HBeta, HY, and HZSM-5), including the mesoporous catalyst of Al-MCM-41. The mask was pyrolyzed in a fixed bed reactor, and the pyrolysis gases evolved in the reactor was routed to a secondary reactor inside which the zeolite catalyst was loaded. It was chosen 550 °C as the CFP temperature to compare the catalyst performance for the production of benzene, toluene, ethylbenzene, and xylene (BTEX) because this temperature gave the highest oil yield (80.7 wt%) during the non-catalytic pyrolysis process. The large pore zeolite group of HBeta and HY led to 134% and 67% higher BTEX concentrations than HZSM-5, respectively, likely because they had larger pores, higher surface areas, and higher acid site density than the HZSM-5. This is the first report of the effect of zeolite characteristics on BTEX production via CFP.