scholarly journals Implications on Feedstock Processing and Safety Issues for Semi-Batch Operations in Supercritical Water Gasification of Biomass

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2863
Author(s):  
Cataldo De Blasio ◽  
Gabriel Salierno ◽  
Andrea Magnano
Keyword(s):  
Heat Transfer ◽  
Supercritical Water ◽  
Control Strategies ◽  
Operation Mode ◽  
Scale Up ◽  
Tubular Reactor ◽  
Large Mass ◽  
Inconel 625 ◽  
Safety Issues ◽  
Supercritical Water Gasification

Biomass with a large amount of moisture is well-suited to be processed by supercritical water gasification, SCWG. The precipitation of inorganics, together with char formation and re-polymerization, can cause reactor plugging and stop the process operations. When plugging occurs, sudden injections of relatively large mass quantities take place, influencing the mass flow dynamics significantly in the process. Reactor plugging is a phenomenon very well observed during SCWG of industrial feedstock, which hinders scale-up initiatives, and it is seldom studied with precision in the literature. The present study provides an accurate evaluation of continuous tubular reactor dynamics in the event of sudden injections of water. An interpretation of the results regarding water properties at supercritical conditions contributes to comprehending mass and heat transfer when plugging occurs. Experiments are then compared to SCWG of a biomass sample aiming to give key insights into heat transfer and fluid dynamics mechanisms that could help develop operational and control strategies to increase the reliability of SCWG. In addition, a simplified model is presented to assess the effect of material integrity on burst-event likelihood, which states that SCWG is safe to operate, at 250 bar and 610 °C, in tubular reactors made of 0.22 wall thickness-to-diameter ratio Inconel-625 with superficial microfractures smaller than 30 µm. We also suggest improvement opportunities for the safety of SCWG in continuous operation mode.

Hydrogen production from glycerol by supercritical water gasification in a continuous flow tubular reactor

2012 ◽  
Vol 37 (7) ◽  
pp. 5559-5568 ◽  
Author(s):  
Simao Guo ◽  
Liejin Guo ◽  
Changqing Cao ◽  
Jiarong Yin ◽  
Youjun Lu ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Supercritical Water ◽  
Continuous Flow ◽  
Tubular Reactor ◽  
Supercritical Water Gasification

scholarly journals Analysis of the Supercritical Water Gasification of Cellulose in a Continuous System Using Short Residence Times

2020 ◽  
Vol 10 (15) ◽  
pp. 5185
Author(s):  
M. Belen García-Jarana ◽  
Juan R. Portela ◽  
Jezabel Sánchez-Oneto ◽  
Enrique J. Martinez de la Ossa ◽  
Bushra Al-Duri
Keyword(s):  
Hydrogen Production ◽  
Supercritical Water ◽  
Tubular Reactor ◽  
Reaction Times ◽  
Theoretical Data ◽  
Continuous System ◽  
Effect Of Temperature ◽  
Residence Times ◽  
Fuel Gas ◽  
Supercritical Water Gasification

Supercritical Water Gasification (SCWG) has the capacity to generate fuel gas effluent from wet biomass without previously having to dry the biomass. However, substantial efforts are still required to make it a feasible and competitive technology for hydrogen production. Biomass contains cellulose, hemicellulose and lignin, so it is essential to understand their behavior in high-pressure systems in order to optimize hydrogen production. As the main component of biomass, cellulose has been extensively studied, and its decomposition has been carried out at both subcritical and supercritical conditions. Most previous works of this model compound were carried out in batch reactors, where reaction times normally take place in a few minutes. However, the present study demonstrates that gasification reactions can achieve efficiency levels of up to 100% in less than ten seconds. The effect of temperature (450–560 °C), the amount of oxidant (from no addition of oxidant to an excess over stoichiometric of 10%, n = 1.1), the initial concentration of organic matter (0.25–2 wt.%) and the addition of a catalyst on the SCWG of cellulose in a continuous tubular reactor at short residence times (from 6 to 10 s) have been studied in this work. Hydrogen yields close to 100% in the gas phase were obtained when operating under optimal conditions. Moreover, a validation of the experimental data has been conducted based on the theoretical data obtained from its kinetics.

scholarly journals Heat Transfer Limitations in Supercritical Water Gasification

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 177
Author(s):  
Francisco Javier Gutiérrez Gutiérrez Ortiz ◽  
Francisco López-Guirao ◽  
Francisco José Jiménez-Espadafor ◽  
José Manuel Benjumea
Keyword(s):  
Heat Transfer ◽  
Supercritical Water ◽  
Experimental Studies ◽  
High Water ◽  
Conventional Heating ◽  
Slow Heating ◽  
High Water Content ◽  
Fluid Temperature ◽  
Factors Affecting ◽  
Supercritical Water Gasification

Supercritical water gasification (SCWG) is a promising technology for the valorization of wet biomass with a high-water content, which has attracted increasing interest. Many experimental studies have been carried out using conventional heating equipment at lab scale, where researchers try to obtain insight into the process. However, heat transfer from the energy source to the fluid stream entering the reactor may be ineffective, so slow heating occurs that produces a series of undesirable reactions, especially char formation and tar formation. This paper reviews the limitations due to different factors affecting heat transfer, such as low Reynolds numbers or laminar flow regimes, unknown real fluid temperature as this is usually measured on the tubing surface, the strong change in physical properties of water from subcritical to supercritical that boosts a deterioration in heat transfer, and the insufficient mixing, among others. In addition, some troubleshooting and new perspectives in the design of efficient and effective devices are described and proposed to enhance heat transfer, which is an essential aspect in the experimental studies of SCWG to move it forward to a larger scale.

PENGGUNAAN AIR SUPER KRITIS PADA DEPOLIMERISASI NYLON-12 (BATCH PROCESS)

2018 ◽  
Vol 5 (3) ◽  
Author(s):  
Mohamad Yusman
Keyword(s):  
Supercritical Water ◽  
Scale Up ◽  
Experimental Studies ◽  
Reaction System ◽  
Batch Process ◽  
Chemical Recycling ◽  
Water Decomposition ◽  
Product Distributions ◽  
New Process ◽  
Nylon 12

Water at the supercritical state is a new process for the chemical recycling. At this thermodynamic state i.e. Pc = 218 atmospheres and Tc = 374oC , water behaves very differently from its everyday temperament and it is a very good solvent for organic components. Experimental studies show that supercritical water can decompose hydrocarbons/polymers and produce useful products like 2-Azacyclotridecanone /lactam-1 from Nylon-12 (batch process). The decomposition process itself was carried out in batch reaction system in order to get more information about product distributions, time dependence, and scale-up possibilities.Keywords: supercritical water, decomposition, batch, polymer, hydrocarbon

Supercritical water gasification of food waste: Effect of parameters on hydrogen production

2020 ◽  
Vol 45 (29) ◽  
pp. 14744-14755 ◽  
Author(s):  
Wei Su ◽  
Changqing Cai ◽  
Ping Liu ◽  
Wei Lin ◽  
Baorui Liang ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Food Waste ◽  
Supercritical Water ◽  
Supercritical Water Gasification
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