Analysis of supercritical water oxidation for detoxification of waste organic solvent in university based on life cycle assessment (original) (raw)
Related papers
Supercritical water oxidation for the treatment of various organic wastes: A review
The removal of complex organic and chemical industrial wastes is not accessible using conventional treatment methods. Incineration and hydrothermal oxidation under supercritical conditions are two options for dealing with a wide range of hazardous wastes. Incineration is an effective treatment for removing hazardous waste. The main disadvantages of incineration are a source of unwanted emissions and high operating costs. Supercritical water oxidation (SCWO) is considered a green technology for destroying organic waste with friendly environmental emissions. The removal efficiency reached 99.99% within a short residence time. In this review, the treatment of organic waste by SCWO is shown using cofuel and catalysts to enhance the performance of SCWO.
Supercritical Water Oxidation: Treatment of Human Waste and System Configuration Tradeoff Study
SAE Technical Paper Series, 1987
Landfill leachate is a complex and variable effluent, rich in organic and inorganic matters resistant to decomposition, and is an extreme pollutant. Humic acids (HA) are some of the most refractive substances in the leachates, which is the reason why they have been used as an organic model. The degradation of an HA solution through supercritical water oxidation (ScWO) was evaluated under a constant pressure of 22.5 MPa, temperatures from 400°C-600°C, and reaction times from 15 seconds-60 seconds. The results showed that the most influential factor was temperature and it guided the operational conditions of the ScWO for the landfill leachate (22.5 MPa, 600°C, and 60 seconds). The landfill leachate treatment promoted high removal rates of true colour (87%), total dissolved solids (94%), nitrate (70%), and total phosphorus (96%). In addition, it removed 57% of the COD, which was similar to the HA removal rate (61%) under the same operational conditions. This indicates that HA are an adequate organic model for landfill leachates. The results suggest that ScWO is a clean and This article is protected by copyright. All rights reserved. promising treatment technology that can be applied to landfills and can have even better results if used in combination with oxidizers and catalysts, or with the use of higher temperatures.
Journal of Chemical Technology & Biotechnology, 2011
BACKGROUND: Supercritical water oxidation (SCWO) is a promising technology that respects the environment, destroys wastes and allows energy recovery. This process has been applied to many model compounds and real wastewaters at laboratory scale. However, SCWO treatments at pilot plant scale of real wastewaters are scarce. The application of this technology to industrial wastewaters has drawbacks such as corrosion, salt deposition and high cost, so industrial scale-up has been delayed. RESULTS: In a first stage, for safety reasons the feasibility of SCWO applied to flammable industrial wastewaters was evaluated at laboratory scale in an isothermal plug flow reactor with low concentrations (3-10 g COD L −1), at a constant pressure of 250 bar and at different temperatures in the range 350-500 • C. In a second stage, experiments were conducted with much higher concentrations (20-90 g COD L −1) in a SCWO reactor at pilot plant scale. Experiments at pilot plant scale demonstrated the possibility of working under autothermal conditions and the results were used to estimate the treatment costs for a SCWO plant with a capacity of 1 m 3 h −1. CONCLUSION: Results demonstrated the technical feasibility of using a SCWO process to treat flammable industrial wastewater at pilot plant scale due to the absence of operational drawbacks related to the flammability of this wastewater, such as plugging, pressurization or preheating problems and uncontrolled reactions (explosion, etc.). The economic feasibility was demonstrated, especially bearing in mind the energy recovery optimization.
The treatment of wastewaters by supercritical water oxidation
Desalination and Water Treatment, 2011
In this study, the treatment performance of SCWO process is evaluated on various industrial wastewaters such as textile dyehouse effluent; pesticide containing model wastewater; olive mill wastewater and cheese whey. These wastewaters have significant pollution potentials due to their high organic loads. The experiments were made under sub- and supercritical conditions in a continuous flow reactor, using H2O2 as the oxygen source. The removal efficiencies are evaluated in terms of total organic carbon concentrations (TOC). The results demonstrate that at various experimental conditions, SCWO provides high organic conversion yields up to 100% in very short reaction times within 30 s for each wastewater sample.
Environmental assessment of supercritical water oxidation and other sewage sludge handling options
Waste management & research : the journal of the International Solid Wastes and Public Cleansing Association, ISWA, 2005
Sustainable development relies on the eco-efficient use of all flows in society; more value created out of each resource unit. Supercritical water oxidation (SCWO) can be used for treatment of wet organic waste. The technology has been under development for over 20 years but has not yet been fully commercialized. SCWO allows for complete oxidation of all organics in sewage sludge and almost complete recovery of the inherent energy, essentially without harmful emissions. In this paper, a life-cycle assessment (LCA) of sewage sludge SCWO (Aqua-Critox) is presented and the results are compared with LCA results for other sludge handling options: agricultural use, co-incineration with municipal solid waste, incineration with subsequent phosphorus extraction (Bio-Con) and sludge fractionation with phosphorus recovery (Cambi-KREPRO). For SCWO, beneficial utilization of the heat of reaction is of crucial importance for the outcome. The electricity consumed by pumping and the nitrous oxide p...
Symmetry
This work reports supercritical water oxidation (SCWO) of organic pollutants in industrial wastewater in the absence and presence of catalysts. To increase the efficiency of the oxidation process, the SCWO of organic compounds in industrial wastewater was performed in the presence of various iron- and manganese-containing heterogeneous catalysts (Fe-Ac, Fe-OH, and Mn-Al). The catalytic and non-catalytic SCWO of organic compounds in wastewater from PJSC “Nizhnekamskneftekhim”, generated from the epoxidation of propylene with ethylbenzene hydroperoxide in the process of producing propylene oxide and styrene (PO/SM), was performed. The effect of operational parameters (temperature, pressure, residence time, type of catalysts, oxygen excess ratio, etc.) on the efficiency of the process of oxidation of organic compounds in the wastewater was studied. SCWO was studied in a flow reactor with induction heating under different temperatures (between 673.15 and 873.15 K) and at a pressure of 2...
Environmental sciences : an international journal of environmental physiology and toxicology, 2006
For the on-site treatment of laboratory waste, we have been developing a compact-sized reaction system for the treatment of laboratory wastewater using supercritical water oxidation (SCWO) technology. Pharmaceutical laboratory wastewater is one of the most difficult wastewaters to treat because of its high concentration of halogenated organic compounds. We proposed a new cascade process in which two reactors are consecutively combined, carrying out hydrolysis in the first reactor followed by SCWO in the second reactor, for the complete removal of halogenated organic compounds. Dichloromethane was chosen as a representative model of chlorinated compounds. There have been many previous studies on the hydrolysis of dichloromethane, which results in the coproduction of formaldehyde and HCl. However, there has been less investigation on the kinetics of formaldehyde oxidation in supercritical water. In this study, we focus on the oxidation of formaldehyde in supercritical water with and w...
Environmental assessment of supercritical water oxidation of sewage sludge
Resources, Conservation and Recycling, 2004
Environmental aspects of using supercritical water oxidation (SCWO) to treat sewage sludge were studied using a life cycle assessment (LCA) methodology. The system studied is the first commercial scale SCWO plant for sewage sludge in the world, treating sludge from the municipal wastewater treatment facility in Harlingen, TX, USA. The environmental impacts were evaluated using three specific environmental attributes: global warming potential (GWP), photo-oxidant creation potential (POCP) and resource depletion; as well as two single point indicators: EPS2000 and EcoIndicator99. The LCA results show that for the described process, gas-fired preheating of the sludge is the major contributor to environmental impacts, and emissions from generating electricity for pumping and for oxygen production are also important. Overall, SCWO processing of undigested sewage sludge is an environmentally attractive technology, particularly when heat is recovered from the process. Energy-conserving measures and recovery of excess oxygen from the SCWO process should be considered for improving the sustainability potential.
A computational model for supercritical water oxidation of organic toxic wastes
Advances in Environmental Research, 2000
Ž. Ž. A computational fluid dynamics CFD model was proposed to simulate the supercritical water oxidation SCWO Ž. process for organic wastes. The SUPERTRAPP code by NIST for thermodynamic and transport properties of hydrocarbon mixtures was incorporated into the commercialized general purpose CFD code CFD-ACE for flow under supercritical pressure. The global kinetic models for supercritical water oxidation of methanol and methane Ž. developed at MIT Energy Lab were implemented and validated in the CFD-ACE framework against experimental data from a tubular reactor. A series of parametric studies to investigate flow rates, thermal boundary conditions and reactor geometry was performed for methane SCWO in a co-axial reactor and the optimized operating conditions and reactor geometry were obtained. Detailed three-dimensional flow, heat and chemistry simulations of methanol SCWO in the CSTR at MIT Energy Lab were also performed with predicted conversions comparable to measurements.
2020
In this study the environmental performance of a first-of-its-kind integrated process based on supercritical water gasification and oxidation (SCW-GcO), was evaluated using life cycle assessment (LCA). The process was applied to the treatment of carbon black and used oil as model wastes. Mass and energy balances were performed using Aspen Plus, and the environmental assessment was carried out through SimaPro. A “from cradle to grave” approach was chosen for the analysis, considering impact categories such as climate change, ozone depletion, human toxicity, particulate matter, land use, resource depletion, and other relevant indicators. The environmental profile of the SCW-GcO process was compared to other technologies for the treatment of dangerous wastes, solvent mixtures, and exhaust mineral oils by using the Ecoinvent database. It is shown that SCW-GcO allows for reduced impacts in different categories and the obtention of a favorable positive life cycle energy balance, achieving...