In this work, the techno-economic analysis of a 20,000 metric ton (MT) green ammonia production facility is presented. This facility is 30 times smaller than a large-scale conventional process, producing ammonia from totally renewable resources: hydrogen from water electrolysis and nitrogen from pressure swing adsorption. Two different configurations of the Haber–Bosch (HB) process are investigated: high-pressure reaction-condensation (RXN-CON) and low-pressure reaction-absorption (RXN-ABS). Process simulation was implemented using ASPEN Plus, where the reactor and absorber columns were designed as a custom model. The results obtained were then used to estimate the total capital and operating costs. The high-pressure processing improves the single-pass conversion and loop efficiency but relies on costly compression, whereas the low-pressure processing is more favorable for both capital and operating costs. The performance analysis of the HB process indicates that the operating pressure affects ammonia production costs. The levelized cost of ammonia (LCOA) from our small-scale Haber process was found to be about twice more expensive than the conventional commodity ammonia prices. Our sensitivity analysis suggests that inherently safer low-pressure RXN-ABS can be utilized for thermochemical energy storage of renewable resourcesfor scenarios that numerous small ammonia plants can be implemented in areas with local ammonia demand, with access to excess renewable electricity at the time of high penetration of renewable resources. Under such conditions, the LCOA from this plant can be comparable with the ammonia commodity prices. When the revenue from selling oxygen is considered into economics, small-scale all-electric ammonia can be profitable with an after-tax rate of return of 27.50% for RXN-ABS.

Laser-induced graphene (LIG) has recently gained significant attention for its potential application in various fields.Here, we show that the laser ablation of Kevlar fabric, polyimide (PI), and poly(ether)sulfone (PES) substrates results in the formation of a highly porous graphene with different physicochemical features. LIG powder was used as an adsorbent for the dye removal. The LIG materials obtained from each substrate exhibited a different macroporous structure and demonstrated relatively high efficiency in the adsorptive removal of cationic dye. The generation of graphene from each polymeric substrate was confirmed by characterizing the LIGs. We found that the laser power had a large influence on the formation and quality of the LIG; higher laser power increased the degree of graphitization and resulted in a more porous graphene structure, which eventually led to an increase in the adsorption capacity. The LIG's adsorption capability is hypothesized to be primarily due to the highly porous structure of LIG, while π−π and hydrophobic interactions were found to have a marginal influence on the adsorbent−adsorbate interactions. LIG derived from PI displayed the highest sorption capacity among different polymeric substrates tested. The maximum equilibrium methylene blue adsorption capacity was found to be 153.3 mg/g using the Langmuir model.

No abstract

No abstract

No abstract