scholarly journals Supercritical Water Gasification of Municipal Sludge: A Novel Approach to Waste Treatment and Energy Recovery

Author(s):  
Jonathan Kamler ◽  
J. Andres
Holzforschung ◽  
2015 ◽  
Vol 69 (6) ◽  
pp. 751-760 ◽  
Author(s):  
Marion Huet ◽  
Anne Roubaud ◽  
Dominique Lachenal

Abstract Supercritical water gasification of weak sulfur-free black liquor (BL) was performed in a batch autoclave at temperatures between 430°C and 470°C, pressure between 24 and 27 MPa and residence time between 2 and 63 min. Results show that the gas produced was a mixture of mainly hydrogen, methane, and carbon dioxide. Maximum conversion was achieved at 470°C and 60 min. Energy recovery (ER, ratio between the energy in the gas and in the initial BL) was 46%. Thirty-four percent of the carbon and 53% of the hydrogen initially present in BL were converted into gases. Nearly 15% of initial organic carbon remains in the liquid phase and consists mainly of phenolic compounds, which are stable under those conditions. A higher temperature is needed to convert all the organic carbon. Thermodynamic equilibrium should be reached at 700°C leading to a complete conversion and a better efficiency. Sodium recovery is close to typical kraft recovery value and compatible with causticizing.


Energy ◽  
2021 ◽  
pp. 121184
Author(s):  
Yaping Hu ◽  
Junhao Lin ◽  
Qinxiong Liao ◽  
Shichang Sun ◽  
Rui Ma ◽  
...  

2020 ◽  
Vol 45 (29) ◽  
pp. 14744-14755 ◽  
Author(s):  
Wei Su ◽  
Changqing Cai ◽  
Ping Liu ◽  
Wei Lin ◽  
Baorui Liang ◽  
...  

2021 ◽  
pp. 1-11
Author(s):  
Aysu Melis Buyuk ◽  
Gul T. Temur

In line with the increase in consciousness on sustainability in today’s global world, great emphasis has been attached to food waste management. Food waste is a complex issue to manage due to uncertainties on quality, quantity, location, and time of wastes, and it involves different decisions at many stages from seed to post-consumption. These ambiguities re-quire that some decisions should be handled in a linguistic and ambiguous environment. That forces researchers to benefit from fuzzy sets mostly utilized to deal with subjectivity that causes uncertainty. In this study, as a novel approach, the spherical fuzzy analytic hierarchy process (SFAHP) was used to select the best food treatment option. In the model, four main criteria (infrastructural, governmental, economic, and environmental) and their thirteen sub-criteria are considered. A real case is conducted to show how the proposed model can be used to assess four food waste treatment options (composting, anaerobic digestion, landfilling, and incineration). Also, a sensitivity analysis is generated to check whether the evaluations on the main criteria can change the results or not. The proposed model aims to create a subsidiary tool for decision makers in relevant companies and institutions.


Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 455
Author(s):  
Nikolaos Boukis ◽  
I. Katharina Stoll

Gasification of organic matter under the conditions of supercritical water (T > 374 °C, p > 221 bar) is an allothermal, continuous flow process suitable to convert materials with high moisture content (<20 wt.% dry matter) into a combustible gas. The gasification of organic matter with water as a solvent offers several benefits, particularly the omission of an energy-intensive drying process. The reactions are fast, and mean residence times inside the reactor are consequently low (less than 5 min). However, there are still various challenges to be met. The combination of high temperature and pressure and the low concentration of organic matter require a robust process design. Additionally, the low value of the feed and the product predestinate the process for decentralized applications, which is a challenge for the economics of an application. The present contribution summarizes the experience gained during more than 10 years of operation of the first dedicated pilot plant for supercritical water gasification of biomass. The emphasis lies on highlighting the challenges in process design. In addition to some fundamental results gained from comparable laboratory plants, selected experimental results of the pilot plant “VERENA” (acronym for the German expression “experimental facility for the energetic exploitation of agricultural matter”) are presented.


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