Catalytic Supercritical Water Gasification of Refuse Derived Fuel for High Energy Content Fuel Gas

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.

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Upgrading of automobile shredder residue via innovative granulation process ‘ReGran’

Waste Management & Research ◽

10.1177/0734242x16677077 ◽

2016 ◽

Vol 35 (1) ◽

pp. 110-119

Author(s):

Philip Holthaus ◽

Moritz Kappes ◽

Wolfgang Krumm

Keyword(s):

Bulk Density ◽

Energy Content ◽

High Energy ◽

Rotational Frequency ◽

Regulatory Requirements ◽

Granulation Process ◽

Shredder Residue ◽

Automobile Shredder Residue ◽

Refuse Derived Fuel ◽

Interesting Possibility

Stricter regulatory requirements concerning end-of-life vehicles and rising disposal costs necessitate new ways for automobile shredder residue utilisation. The shredder granulate and fibres, produced by the VW-SICON-Process, have a high energy content of more than 20 MJ kg−1, which makes energy recovery an interesting possibility. Shredder fibres have a low bulk density of 60 kg m−3, which prevents efficient storing and utilisation as a refuse-derived fuel. By mixing fibres with plastic-rich shredder granulate and heating the mixture, defined granules can be produced. With this ‘ReGran’ process, the bulk density can be enhanced by a factor of seven by embedding shredder fibres in the partially melted plastic mass. A minimum of 26–33 wt% granulate is necessary to create enough melted plastic. The process temperature should be between 240 °C and 250 °C to assure fast melting while preventing extensive outgassing. A rotational frequency of the mixing tool of 1000 r min−1 during heating and mixing ensures a homogenous composition of the granules. During cooling, lower rotational frequencies generate bigger granules with particles sizes of up to 60 mm at 300 r min−1. To keep outgassing to a minimum, it is suggested to melt shredder granulate first and then add shredder fibres. Adding coal, wood or tyre fluff as a third component reduces chlorine levels to less than 1 wt%. The best results can be achieved with tyre fluff. In combination with the VW-SICON-Process, ReGran produces a solid recovered fuel or ‘design fuel’ tailored to the requirements of specific thermal processes.

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Supercritical water gasification: a patents review

Reviews in Chemical Engineering ◽

10.1515/revce-2016-0020 ◽

2017 ◽

Vol 33 (3) ◽

Cited By ~ 6

Author(s):

Pau Casademont ◽

M. Belén García-Jarana ◽

Jezabel Sánchez-Oneto ◽

Juan Ramón Portela ◽

Enrique J. Martínez de la Ossa

Keyword(s):

Supercritical Water ◽

New Technology ◽

Hydrothermal Process ◽

Current Status ◽

Light Hydrocarbons ◽

Fuel Gas ◽

High Hydrogen ◽

Operation Conditions ◽

Wet Biomass ◽

Supercritical Water Gasification

AbstractSupercritical water gasification (SCWG) is a very recent technology that allows conversion of organic wastewaters into a fuel gas with a high content of hydrogen and light hydrocarbons. SCWG involves the treatment of organic compounds at conditions higher than those that define the critical point of water (temperature of 374°C and pressure of 221 bar). This hydrothermal process, normally operated at temperatures from 400 to 650°C and pressures from 250 to 350 bar, produces a gas effluent with a high hydrogen content. SCWG is considered a promising technology for the efficient conversion of organic wastewaters, mainly wet biomass, into fuel gas. This technology has received extensive worldwide attention, and many research groups have studied the effect of operation conditions, reaction mechanisms, kinetics, etc. There are some recent reviews about the research works carried out in the last decades, but there is no information or analysis of almost 100 patents registered in relation with this new technology. A revision of the current status of SCWG patents and technologies has been completed based on the Espacenet patent database. The objective of this revision was to set down the new perspectives toward the improvement of this technology efficiency. Patents have been published with regard to process or device improvements as well as to the use of different catalysts. More than 71% of these patents were published since 2009, and a substantial climb in the number of patents on SCWG is expected in the coming years. One of the most important aspects where research is particularly interesting if the integration of renewable energy recovery systems with SCWG processes.

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Exploration of the effect of process variables on the production of high-value fuel gas from glucose via supercritical water gasification

Bioresource Technology ◽

10.1016/j.biortech.2010.11.003 ◽

2011 ◽

Vol 102 (3) ◽

pp. 3480-3487 ◽

Cited By ~ 38

Author(s):

Doug Hendry ◽

Chandrasekar Venkitasamy ◽

Nikolas Wilkinson ◽

William Jacoby

Keyword(s):

Supercritical Water ◽

Process Variables ◽

Fuel Gas ◽

Supercritical Water Gasification

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

Applied Sciences ◽

10.3390/app10155185 ◽

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.

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