Conversion of organic matter in the carbonaceous medium in the supercritical water

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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Char and tar formation during hydrothermal treatment of sewage sludge in subcritical and supercritical water: Effect of organic matter composition and experiments with model compounds

Journal of Cleaner Production ◽

10.1016/j.jclepro.2019.118586 ◽

2020 ◽

Vol 242 ◽

pp. 118586 ◽

Cited By ~ 6

Author(s):

Chenyu Wang ◽

Yujie Fan ◽

Ursel Hornung ◽

Wei Zhu ◽

Nicolaus Dahmen

Keyword(s):

Organic Matter ◽

Sewage Sludge ◽

Hydrothermal Treatment ◽

Supercritical Water ◽

Water Effect ◽

Model Compounds ◽

Organic Matter Composition

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Removal Efficiency of Organic Substance in Municipal Sludge by Supercritical Water Oxidation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.726-731.1732 ◽

2013 ◽

Vol 726-731 ◽

pp. 1732-1738 ◽

Cited By ~ 2

Author(s):

Dan Li ◽

Cong Jun Sun ◽

Jian Feng Ye

Keyword(s):

Organic Matter ◽

Supercritical Water ◽

Water Oxidation ◽

Municipal Wastewater ◽

Wastewater Sludge ◽

Main Reaction ◽

Supercritical Water Oxidation ◽

Municipal Sludge ◽

Study Results ◽

Resident Time

In this study efficiency of organic matter in municipal wastewater sludge treated by supercritical water is investigated. Influences of main reaction parameters, including temperature (380~500°C), pressure (23-30 MPa), residence time (1-10 min), oxidant dose (100%-200%), were evaluated. Orthogonal Array design was applied in order to consider each parameters impact on COD removal. Study results indicate that 97.89% of COD in the sludge sample can be removed in 10min at 500°C, 30MPa and 200% H2O2oxidant excess dose. Temperature, pressure, resident time are main factors to affect the reaction, while oxidant dose has a little effect on removal of COD in municipal wastewater sludge. The conclusion is the organic matter in municipal wastewater sludge can be removed effectively by super critical water oxidation.

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Sub- and supercritical water in the processes of conversion of Domanik rock organic matter

E3S Web of Conferences ◽

10.1051/e3sconf/202126607001 ◽

2021 ◽

Vol 266 ◽

pp. 07001

Author(s):

Z.R. Nasyrova ◽

G.P. Kayukova ◽

A.E. Chemodanov ◽

A.V. Vakhin

Keyword(s):

Organic Matter ◽

Supercritical Water ◽

Mineral Content ◽

Subcritical Water ◽

Complete Recovery ◽

Phase Changes ◽

Saturated Hydrocarbons ◽

Domanik Rock ◽

Intensive Formation ◽

Paramagnetic Properties

Studies on the conversion of organic matter of high-carbon Domanik (siliceous-clay carbonate) rock of the Romashkinskoye deposit with a mineral content Corg of 7.07% in sub- and supercritical water have been carried out. It was shown that subcritical water at a temperature of 320°С and 17.0 MPa leads to a partial decomposition of the kerogenic structure, increasing the yield of bitumen from 3.12 to 3.98%, and a more complete recovery of asphaltenes and heavy C22-C30 n-alkanes from the rock sample. Supercritical water at temperatures of 374 and 420°C and pressures above 24.4 MPa leads to intensive formation of hydrocarbon and inorganic gases in the processes of kerogen decomposition, destruction of aliphatic substituents from condensed heteroatomic structures of resins and asphaltenes, and the carbonate component of Domanik rock. Degradation of the organic matter of the Domanik rock is also accompanied by the formation of saturated hydrocarbons with an increased content of light C12-C21 n-alkanes, and carbonaceous substances, such as carbene-carboids. Changes in the structure of asphaltenes and their paramagnetic properties were determined by the EPR method. The influence of sub- and supercritical water on phase changes in the composition of rock minerals, as well as on the yield and composition of formed gases, was revealed.

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Pilot-Scale Unit for Supercritical Water Gasification of Organic Matter

Waste and Biomass Valorization ◽

10.1007/s12649-020-01266-0 ◽

2020 ◽

Author(s):

Marek Šváb ◽

Eliška Purkarová

Keyword(s):

Organic Matter ◽

Supercritical Water ◽

Pilot Scale ◽

Scale Unit ◽

Supercritical Water Gasification

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Co-Pyrolysis of Polyethylene Plastic and Cellulose as Models for Medical Waste in Supercritical Water

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1010-1012.952 ◽

2014 ◽

Vol 1010-1012 ◽

pp. 952-955 ◽

Cited By ~ 1

Author(s):

Yan Meng Gong ◽

Shu Zhong Wang ◽

Xing Ying Tang

Keyword(s):

Organic Matter ◽

Reaction Time ◽

Supercritical Water ◽

Time Pressure ◽

Batch Reactor ◽

Medical Waste ◽

Oil Yield ◽

Mass Ratio ◽

Gaseous Products ◽

Gasification Efficiency

Co-pyrolysis of polyethylene plastic and cellulose as models for medical waste had been studied on a supercritical water batch reactor. The results show that temperature, reaction time, pressure and the mass ratio of water to organic matter have some degree impact on the conversion rate, oil yield and gasification efficiency. Conversion and gasification efficiency reached the maximum values at 440 °C. The content of H2 in the gaseous products rose significantly between 25 MPa~27 MPa. As reaction time increased, conversion and gasification efficiency increased, but oil yield decreased. The composition of gaseous products was affected greatly by the mass ratio of water to organic matter. Adding K2CO3 and Ca (OH)2 as catalyst, the reaction was promoted obviously.

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Geothermal Transformatiom of Organic Matter in Supercritical Water with Magnetite and Coal Particles

Chemistry and Technology of Fuels and Oils ◽

10.1007/s10553-017-0770-1 ◽

2017 ◽

Vol 52 (6) ◽

pp. 756-761 ◽

Cited By ~ 1

Author(s):

I. M. Zaidullin ◽

A. I. Lakhova ◽

I. A. Ivanova ◽

S. M. Petrov ◽

D. A. Ibragimova ◽

...

Keyword(s):

Organic Matter ◽

Supercritical Water ◽

Coal Particles

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LABORATORY EQUIPMENT FOR AUTOTHERMAL REFORMING OF ORGANIC MATTER IN SUPERCRITICAL WATER

Acta Polytechnica ◽

10.14311/ap.2014.54.0015 ◽

2014 ◽

Vol 54 (1) ◽

pp. 15-18

Author(s):

Matúš Gajdoš

Keyword(s):

Organic Matter ◽

Water Content ◽

Supercritical Water ◽

High Water ◽

Processing Parameters ◽

Autothermal Reforming ◽

High Water Content ◽

Fuel Production ◽

Laboratory Equipment ◽

Efficient Operation

The ability of water to dissolve organic substances is very limited. However, its ability to dissolve them changes if pressure and temperature values reach the so-called critical point (<em>p</em> = 22.06MPa, <em>T</em> = 373.95 °C). Fluid water in this state is called supercritical water (SCW), and values of its physical properties are included among the values of such properties for liquid phase and gaseous phase. Various types of organic matter can be treated in SCW, and it is especially useful for materials that cannot be treated cost-effectively with conventional technologies (incineration, etc.). Suitable input materials are mainly industrial waste or biomass with high water content. Conventional processing of these materials requires energy-intensive drying or densification. Processing the inputs in SCW completely removes these problems, since sufficient water content is a prerequisite for creating a suitable environment for efficient operation of the system. In this paper, glycerol as a by-product of alternative fuel production was chosen for evaluation in the SCW autothermal reforming cycle. The paper analyses the influence of several processing parameters on the operation of model laboratory equipment.

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