Environmental sustainability practice of sewage sludge and low-rank coal co-pyrolysis: A comparative life cycle assessment study.

This study attempts to bridge the current research gaps related to the environmental burdens of low-rank coal (LRC) and sewage sludge (SS) co-pyrolysis potentially. The life cycle assessment (LCA), energy recovery and sensitivity analysis were investigated for different proportions of LRC and SS (co-)pyrolysis. The results showed that the LRC/SS pyrolysis mitigated the environmental burden with an average improvement of 43 % across 18 impact categories compared with SS pyrolysis. The best net values of energy and carbon credits were identified in SL-4 with -3.36 kWh/kg biochar and -1.10 CO2-eq/kg biochar, respectively. This study firstly proposed an optimal LRC/SS co-feed proportion at 3 to 7, which achieves the acceptable environmental burden and satisfactory energy recovery. Moreover, sensitivity analysis demonstrated this proportion is robust and adaptable. LRC/SS co-pyrolysis is a promising and sustainable alternative for SS disposal, which could meet the imperative of carbon emission mitigation and resource recycling.

Synergistic consideration of co-treatment of sewage sludge, low-rank coal, and straw for sustainable resource utilization and enhanced energy efficiency: a review.

This article provides a comprehensive exploration of the imperative necessity for coupling the utilization of low-rank coal, sewage sludge, and straw. It studies the challenges and limitations of individual utilization methods, addressing the unique hurdles associated with feedstocks. It focused on achieving integrated and sustainable resource management, emphasizing efficient resource utilization, waste minimization, and environmental impact reduction. The investigation extends to the intricate details of reaction processes in co-processing, with a specific emphasis on the drying of raw materials to enhance combustion characteristics. The molding and preparation of feedstock are dissected, encompassing raw material selection, mixing, and the crucial addition of additives and binders. The proportions and homogenization of these feedstocks are intricately examined for uniformity and effectiveness. Furthermore, it presents theoretical approaches for investigating the co-combustion of these diverse feedstocks, contributing a solid foundation for future studies in this dynamic field. The findings presented in it offer valuable insights for researchers, practitioners, and policymakers seeking sustainable solutions in the co-disposal technology of these feedstocks. Therefore, it provides a holistic understanding of the challenges and opportunities in coupling the utilization of these selected feedstocks. By addressing individual limitations and emphasizing integrated resource management, the article establishes the groundwork for sustainable and efficient co-processing practices. The exploration of reaction processes gives a comprehensive framework for future research and application in the field of co-combustion technology. The insights gleaned from this study contribute significantly to advancing knowledge in the sustainable utilization of diverse feedstocks, guiding efforts towards environmentally responsible and resource-efficient practices.

Synergistic blending of biomass, sewage sludge, and coal for enhanced bioenergy production: Exploring residue combinations and optimizing thermal conversion parameters.

Creating renewable energy from lignocellulosic biomass is essential for a sustainable future. Due to their abundance and the possibility of producing cheap and clean energy, non-lignocellulosic wastes like sewage sludge from industrial and municipal wastes have drawn attention as a feasible alternative to fossil fuels. These abundant, cost-effective resources may help minimize the effects of climate change since they produce less pollution. Several drawbacks are associated with using sewage sludge in thermal conversion procedures. These issues encompass suboptimal energy yield, elevated ash levels in the final product, and subpar biomass quality. Using these scraps in conjunction with coal might enhance energy conversion processes. This study has revealed the necessity for further investigation into how various combinations of residues interact with each other, influencing synergistic effects and degradation processes. The study's underlying objective was to provide a centralized database on the synergistic effects of mixing biomass and sewage sludge for bioenergy production, coal and biomass, and coal and sewage sludge through thermochemical processes like combustion, pyrolysis, gasification, and hydrolysis with Aspen Plus. This study will assist in enhancing biofuels' output from sewage sludge, coal, and coal/biomass blends in thermal conversion by defining the operating parameters (temperature, heat, and residence duration) of pyrolysis and combustion, features, and chemical properties that may influence these processes.

Conversion of low-rank coal and sewage sludge into syngas for H2SO4 production and straw hydrolysis.

This study investigates the potential of using sewage sludge and low-rank coal for the sustainable production of sulfuric acid, which can then be used for the hydrolysis of straw through ASPEN PLUS simulation. Pyrolysis and gasification processes were used to convert sewage sludge and low-rank coal into syngas, which were then purified and oxidized to produce H2SO4 and NH3 gas. The pyro-gasification enhanced syngas yield. The effects of key process parameters such as temperature, steam-to-biomass ratio, equivalence ratio, and feedstock composition on the yield and composition of syngas and H2SO4 coupled with minor parameters like pressure were investigated. The simulation was conducted over the temperature and pressure range of 400 - 900°°C and 70 - 150 kPa respectively. While the steam-to-biomass ratio and equivalence ratio were respectively varied from 0.66 - 1.65 and 0.14 - 0.35. Part of the 1012.88 kg/h of H2SO4 produced was used to hydrolyze straw, producing glucose as a valuable feedstock for biorefineries. About 3989.10 kg/h of NH3 was produced. Results showed that the use of sewage sludge and low-rank coal as feedstocks for syngas production can be a sustainable and cost-effective alternative to traditional fossil fuels. The resulting H2SO4 can also be used for various other applications, such as in the production of fertilizers and detergents. Overall, this study agrees with the literature, demonstrates the potential of integrating biomass and waste resources for the sustainable production of high-value chemicals and fuels, and contributes to the field of sustainable chemical and energy production while addressing environmental and economic considerations.

Advancements in low-temperature NH3-SCR of NOx using Ba-based catalysts: a critical review of preparation, mechanisms, and challenges.

Presently, selective catalytic reduction (SCR), with either carbon monoxide, urea, hydrocarbons, hydrogen, or ammonia as a reductant, has become a nitrogen oxide (NOx) removal technology (NOx conversion) of many catalytic companies and diesel engine exhaust gas. Although, there exists a serious threat of low-temperature limitations. So far, certain scientists have shown that barium-based (Ba-based) catalysts have the potential to be highly effective at SCR of NOx at low temperatures when ammonia is used as the reducing agent. The process of NOx storage and reduction which alternate SCR is known as the Lean NOx trap. Herein, we give the condensed advancements and production of the catalysts that involve BaO in low-temperature NH3-SCR of NOx, the advantages of BaO catalysts compared to the recently hot electrocatalysis, the stability of BaO catalyst materials, and the condensed advancements and production of the catalysts that involve BaO in low-temperature NH3-SCR of NOx. These catalysts are viewed in the light of their preparation method, particulate, and posture in mixed oxides. Also, the characteristic features of Ba-based catalysts are carefully considered and briefed under the following areas: preparation method and precursor, crystallinity, calcination temperature, morphology, acid sites, the specific surface area for reaction, redox property, and activation energy of catalysts. More to these are the discussions on Eley-Rideal [E-R] and Langmuir-Hinshelwood [L-H] mechanisms, the H2O/SO2 and O2 permissiveness, and the NH3-SCR reaction mechanism over Ba-based catalysts highlighting their possible effects. Finally, we proposed the prospect and the likely future research plan for the low-temperature NH3-SCR of NOx.