Sulfur Transformations during Supercritical Water Oxidation of Methanthiol and Thiirane

2012 ◽  
Vol 610-613 ◽  
pp. 1377-1380 ◽  
Author(s):  
Hong He Ma ◽  
Shu Zhong Wang ◽  
Lu Zhou
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Conversion Rate ◽  
Flow Reactor ◽  
Stoichiometric Ratio ◽  
Supercritical Water Oxidation ◽  
Liquid Products ◽  
Tubular Flow Reactor ◽  
Tubular Flow ◽  
Sulfur Containing

The oxidation of methanthiol and thiirane in supercritical water was explored by using a tubular-flow reactor system using oxygen as oxidant. No sulfur containing species existed in the gaseous effluent. Sulfide, sulfite and sulfate were detected as the sulfur containing species in the liquid effluent for supercritical water oxidation (SCWO) of methannthiol, while it was determined as thiosulfate, sulfite and sulfate for SCWO of thiirane. When reaction temperature exceeded 873K, the sulfur contained in the methanthiol or thiirane all transformed into the liquid products. Oxidant stoichiometric ratio had little effect on the conversion rate of sulfur but could promoted sulfite converted into sulfate. Sulfide and thiosulfate were determined as the exclusive sulfur containing product arising directly from methanthiol and thiirane, respectively. The transformation pathways of sulfur contained in the methanthiol and thiirane were proposed as methanthiol-sulfide-sulfite-sulfate and thiirane-thiosulfate-sulfite-sulfate, respectively.

Experimental Study on Supercritical Water Oxidation of Paper Mill Sludge

2014 ◽  
Vol 955-959 ◽  
pp. 711-715 ◽  
Author(s):  
Li Li Qian ◽  
Shu Zhong Wang ◽  
Jie Zhang
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Paper Industry ◽  
Paper Mill ◽  
National Standards ◽  
Supercritical Water Oxidation ◽  
Paper Mill Sludge ◽  
Temperature Oxidation ◽  
Liquid Products ◽  
Transparent Liquid

Paper industry produces large amounts of sludge with about 65wt% moisture content. Due to its complex composition, the charge of traditional disposal method is high and easy to bring about secondary pollution. In this paper, the influences of temperature, oxidation coefficient and residence time on the performance of supercritical water oxidation (SCWO) of paper mill sludge were investigated. The results show that SCWO can almost completely eliminate organics in sludge and obtain transparent liquid products meeting relative national standards at 550°C, 5min with an oxidation coefficient of 3.0. However, during this process, TN changes to NH3-N, so NH3-N in liquid products increases with operation parameters, indicating the recalcitrant nature of NH3-N, and which needs further treatment.

An inclined plug-flow reactor design for supercritical water oxidation

2018 ◽  
Vol 343 ◽  
pp. 351-361 ◽  
Author(s):  
Zhong Chen ◽  
Hongzhen Chen ◽  
Xiaoling Liu ◽  
Chunlan He ◽  
Datian Yue ◽  
...  
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Flow Reactor ◽  
Plug Flow ◽  
Reactor Design ◽  
Plug Flow Reactor ◽  
Supercritical Water Oxidation

scholarly journals In-situ Neutron Tomography on Mixing Behavior of Supercritical Water and Room Temperature Water in a Tubular Flow Reactor

2015 ◽  
Vol 69 ◽  
pp. 564-569 ◽  
Author(s):  
Seiichi Takami ◽  
Ken-ichi Sugioka ◽  
Kyohei Ozawa ◽  
Takao Tsukada ◽  
Tadafumi Adschiri ◽  
...  
Keyword(s):  
Supercritical Water ◽  
Room Temperature ◽  
Flow Reactor ◽  
Neutron Tomography ◽  
Mixing Behavior ◽  
Tubular Flow Reactor ◽  
Tubular Flow ◽  
Temperature Water

Supercritical water oxidation of quinoline in a continuous plug flow reactor—part 2: kinetics

2006 ◽  
Vol 81 (6) ◽  
pp. 919-926 ◽  
Author(s):  
Lisete DS Pinto ◽  
Luisa M Freitas dos Santos ◽  
Regina CD Santos ◽  
Bushra Al-Duri
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Flow Reactor ◽  
Plug Flow ◽  
Plug Flow Reactor ◽  
Supercritical Water Oxidation

Kinetics of Ethylenediamine Wastewater Oxidation in Supercritical Water

2012 ◽  
Vol 531 ◽  
pp. 516-519 ◽  
Author(s):  
Jia Ming Zhang ◽  
Chun Yuan Ma
Keyword(s):  
Residence Time ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Flow Reactor ◽  
Plug Flow ◽  
Excess Oxygen ◽  
Supercritical Water Oxidation ◽  
Kinetics Equation ◽  
First Order ◽  
Kinetics Of

The decompositon of ethylenediamine (EDA) in supercritical water oxidation (SCWO) were investigated. The experiments were conducted in an isothermal and vertical continuous plug-flow reactor at 375-500°C, 25 MPa, residence time of 2-80 s, and excess oxygen of 150%. It was found that yields of nitrous oxide, nitrogen, and the denitrification rate increased as temperature and residence time increased. The kinetics for denitrification of EDA was described by a rate law involving first order reaction. The results calculated from kinetics equation reconciled the experimental data.

scholarly journals Supercritical water oxidation for the destruction of hazardous waste: better than incineration

2015 ◽  
Vol 373 (2057) ◽  
pp. 20150013 ◽  
Author(s):  
Bushra Al-Duri ◽  
Faihan Alsoqyani ◽  
Iain Kings
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Isopropyl Alcohol ◽  
Flow Reactor ◽  
Plug Flow ◽  
Reaction Medium ◽  
Supercritical Water Oxidation ◽  
Split Ratio ◽  
N Removal ◽  
Better Than

Supercritical water oxidation (SCWO) is an advanced process mainly employed for the treatment of hazardous stable wastes, otherwise treatable by incineration. It is based on the unique properties of water above its critical point ( T c =675 K, P c =22.2 MPa), making it a superior reaction medium for the destruction of all organics in the presence of oxygen. This work presents preliminary laboratory scale studies on SCWO of nitrogen (N)-containing hazardous hydrocarbons, with a view to enhancing the process performance, using available reagents and non-complex reactor design. This article investigates the destruction of dimethylformamide (DMF), carried out in a continuous (plug flow) reactor system. SCWO of DMF was enhanced by (i) a split-oxidant system, where stoichiometric oxidant was divided between two inlet ports at various ratios and (ii) the addition of isopropyl alcohol (IPA) as a co-fuel, premixed with the feedstock. Testing a range of temperatures, initial DMF concentrations, oxidant ratios, IPA ratios and oxidant split ratios, selected results were presented in terms of % total organic carbon and % N removal. Reaction kinetics were studied and showed a dramatic decrease in the activation energy upon adding IPA. Split-oxidant-feeding enhancement depended on the split ratio and secondary feed position.

Treatability of Phenol by Supercritical Water Oxidation

2011 ◽  
Vol 422 ◽  
pp. 462-465
Author(s):  
Hui Li ◽  
En Zhao
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Continuous Flow ◽  
Flow Reactor ◽  
Reaction Times ◽  
Supercritical Water Oxidation ◽  
Continuous Flow Reactor ◽  
Organic Destruction ◽  
Water Conditions ◽  
Phenol Wastewater

This study focused on the treatment of phenol wastewater by supercritical water oxidation(SCWO). Tests were conducted by using a continuous-flow reactor system. Based on COD, organic destruction efficiencies of phenol wastewater were obtained at supercritical water conditions. Temperatures and pressures, respectively, ranged from 400-500°C,and 25-40Mpa. The reaction times varied from 30 to 190 seconds, and hydrogen peroxide was used as oxidant. Under SCWO conditions, destruction efficiencies greater than 99% were achieved.

scholarly journals Supercritical Water Oxidation of 3-Methylpyridine with Propylene Glycol

2021 ◽  
Vol 33 (7) ◽  
pp. 1573-1578
Author(s):  
Falah Kareem Hadi Al-Kaabi ◽  
Bushra Al-Duri ◽  
Iain Kings
Keyword(s):  
Propylene Glycol ◽  
Removal Efficiency ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Isopropyl Alcohol ◽  
Flow Reactor ◽  
Hydroxyl Groups ◽  
Supercritical Water Oxidation ◽  
Toc Removal ◽  
Positive Effect

The destruction of 3-methylpyridine by supercritical water oxidation (SCWO) using propylene glycol (PG) and isopropyl alcohol (IPA) as co-fuels in a plug flow reactor was carried out. Hydrogen peroxide was the oxygen source. All the experiments were carried out at 25 MPa and a range of temperatures from 425-525 ºC. The residence times range from 6 s to 14 s. Results were presented in terms of total organic carbon (TOC) as a function of time with various process parameters. The findings support the positive effect that propylene glycol has on the destruction of 3-methylpyridine, where TOC removal is ≥ 97.5% at 525 ºC and 14 s. The maximum TOC removal efficiency is 93% at 425 ºC, 14 s, and the [propylene glycol]/[3-methylpyridine]o ratio of 3. The removal efficiency of nitrogen in the presence of propylene glycol reaches 89% at 525 ºC and 10 s. The oxidant ratio also has a positive effect on the removal of TOC in the three systems. Addition of propylene glycol causes a significant development in the ratio at 425 ºC, more so than when isopropyl alcohol was added. This is due to two hydroxyl groups in propylene glycol oxidation that enhance the reaction by generating various free radicals.

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