Development of a System for the Study of Solid Fuel Conversion Under Supercritical Water Conditions

2012 ◽  
Author(s):  
Bumjick Kim ◽  
Reginald E. Mitchell
Keyword(s):  
Flow Rate ◽  
Supercritical Water ◽  
Flow Reactor ◽  
Biomass Conversion ◽  
Low Cost ◽  
Reaction Medium ◽  
Rate Coefficients ◽  
Feed Water ◽  
Data Sets ◽  
Solids Content

Due to its low cost and abundance, a large amount of coal and biomass is still being used to generate electricity throughout the world. Given that these solid fuels are here to stay for the foreseeable future, the problem of their environmental impact in terms of their emission of CO2 and harmful gas streams will remain unless solutions to it can be found. Supercritical water (SCW) is an attractive medium for power generation because of its special characteristics. Organic compounds extracted from coal and biomass hydrolyze, and they are completely miscible in SCW. In contrast, sulfur, chlorine and many trace elements in coal are oxidized and form insoluble salts in SCW, which precipitate and can be removed. The coal/biomass-to-electricity scheme takes advantage of these characteristics of SCW in using it as a reaction medium. A description of the experimental facility to conduct experiments for pulverized coal and biomass conversion under SCW conditions (P>218 atm and T>647 K) is provided. The facility includes high-pressure water pumps, pulse-dampening accumulators, a water preheater, an oxygen booster, a SCW gasification reactor, and a reaction quenching cooler. This work presents the entire coal/biomass conversion system, built and assembled, which permits the acquisition of data needed to determine the rate coefficients for reactions that are suitable for SCW conditions. The focus of the facility is a flow reactor that can be pressurized up to 340 atm at temperatures up to 750 K. The continuous flow reactor is 15 meters long, sufficient for residence times as long as 15 minutes when the total mass flow rate (slurry plus SCW flow rates) is 20 grams/min. The residence time in the reactor is varied by controlling the solids content of the slurry and the flow rate of the water supplied. The feed water is pressurized and preheated to the test conditions before the solids slurry and any oxygen are admitted. Oxygen is added so that the heat release from partial oxidation of the solids can supply energy for autothermal gasification. The facility developed is in operation to collect data sets for the characterization of conversion mechanism.

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.

Near Term Application of Supercritical Water Technologies

2006 ◽  
Author(s):  
Bastian Vogt ◽  
Joerg Starflinger ◽  
Thomas Schulenberg
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Supercritical Water ◽  
Feed Water ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Exit Temperature ◽  
Near Term ◽  
Safety Features

A pressurized water reactor with a supercritical water primary loop is analyzed (PWR-SC) within this paper. It will be shown that the PWR-SC offers considerable advantages in the fields of safety, economy and efficiency compared with a conventional PWR design. A cycle analysis shows that the net plant efficiency increases by 2% compared to currently operated or built systems. In addition, the mass flow rate of the primary side is strongly decreased, which enables a reduction of the primary pump power by a factor of 4. In the secondary loop, the mass flow rate can be decreased by about 15%, which allows downscaling of all secondary side components such as turbines, condensers and feed-water preheat systems as a consequence of the high core exit temperature. A coupled core analysis and a hot channel factor analysis are performed to demonstrate the promising safety features of the PWR-SC and to show the technical feasibility of such a system.

Transient Analysis of Supercritical Water-Cooled Reactor with Main Feed-Water Parameter Changing

2012 ◽  
Vol 516-517 ◽  
pp. 817-823
Author(s):  
Juan Chen ◽  
Tao Zhou ◽  
Feng Luo ◽  
Han Ding Wang
Keyword(s):  
Flow Rate ◽  
Supercritical Water ◽  
Transient Analysis ◽  
Coupling Model ◽  
Calculation Model ◽  
Hydraulic Calculation ◽  
Feed Water ◽  
Steam Temperature ◽  
Transient Characteristics ◽  
Main Steam

Based on a transient analysis code that developed with coupled neutron and thermal hydraulic calculation model for supercritical water reactor, the transient characteristics under feed-water parameter changing is detailed analyzed, including temperature decreasing, flow-rate decreasing and pressure increasing. The results show that, if no control system action given, flow rate or temperature decreasing would lead to the increase of main steam temperature and decrease of core power, but pressure increasing shows a little influence. If control systems are put into operation, transient characteristics will be obviously changed but finally recovered to normal level. As the same changing percentage 3% is selected, main steam temperature during pressure decreasing transient can reach its highest level in 510.9°C, and return to normal at the time of 90s. But for feed-water temperature decreasing transient, main steam temperature shows an obvious fluctuation during its adjustment and returns to normal until 170s from 503°C. In addition, compared with the results calculated by non-coupling calculation model, main steam temperature calculated by above coupling model shows a smaller deviation but a little longer time needed for returning to its normal value.

scholarly journals Off-Design Dynamic Performance Analysis of a Solar Aided Coal-Fired Power Plant

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2950
Author(s):  
Vinod Kumar ◽  
Liqiang Duan
Keyword(s):  
Power Plant ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Dynamic Performance ◽  
Feed Water ◽  
Saving Rate ◽  
Coal Consumption ◽  
Dynamic Performance Analysis

Coal consumption and CO2 emissions are the major concerns of the 21st century. Solar aided (coal-fired) power generation (SAPG) is paid more and more attention globally, due to the lesser coal rate and initial cost than the original coal-fired power plant and CSP technology respectively. In this paper, the off-design dynamic performance simulation model of a solar aided coal-fired power plant is established. A 330 MW subcritical coal-fired power plant is taken as a case study. On a typical day, three various collector area solar fields are integrated into the coal-fired power plant. By introducing the solar heat, the variations of system performances are analyzed at design load, 75% load, and 50% load. Analyzed parameters with the change of DNI include the thermal oil mass flow rate, the mass flow rate of feed water heated by the solar energy, steam extraction mass flow rate, coal consumption, and the plant thermal efficiency. The research results show that, as DNI increases over a day, the coal saving rate will also increase, the maximum coal saving rate reaches up to 5%, and plant thermal efficiency reaches 40%. It is analyzed that the SAPG system gives the best performance at a lower load and a large aperture area.

The Effect of Air Injection Method on the Airlift Pump Performance

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Dong Hu ◽  
Chuan-Lin Tang ◽  
Shu-Peng Cai ◽  
Feng-Hua Zhang
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Low Cost ◽  
Air Injection ◽  
Water Volume ◽  
Pump Design ◽  
Pump Performance ◽  
Dimensionless Equation ◽  
Measurement Results ◽  
Injection Methods

With simple structure, excellent reliability, low cost, no restriction at depth of water, and easy control and operation, airlift pumps have special advantage in borehole hydraulic jet mining, river dredging and deep sea mining. To clarify the mechanism and process of action of air injection methods on air lift performance, and to enhance lifting capacity, the pump performance of a small airlift system in transporting river sands is investigated experimentally in the present study. The results are as the follows. The influences of air exit ports on water volume flow rate, mass flow rate of solids and lifting efficiency are studied and found to be very low when the number of air exit ports exceeds 3. The pump design show best pumping capability for water and solids at higher air flow rates, but the lifting efficiency is then very low. In addition, a dimensionless equation which describes the flows in the pipe is presented based on the Bernoulli equation, and compared with measurement results in the dimensionless form, which are nearly in good agreement with each other for all the arrangements of air exit ports and are basically contained within ±18% of the theoretical curve. The results are important for understanding the mechanism of airlift pumps and enriching multiphase flow theory.

An analytical and experimental study of a hybrid rocket motor

2014 ◽  
Vol 228 (13) ◽  
pp. 2475-2486 ◽  
Author(s):  
Hadi Rezaei ◽  
Mohammad Reza Soltani
Keyword(s):  
Flow Rate ◽  
Low Cost ◽  
Specific Impulse ◽  
Combustion Products ◽  
Rocket Motor ◽  
Chamber Pressure ◽  
Hybrid Rocket ◽  
Hybrid Rocket Motor ◽  
Chemical Propulsion ◽  
Rate Case

The hybrid rocket motor is a kind of chemical propulsion system that has been recently given serious attention by various industries and research centers. The relative simplicity, safety and low cost of this motor, in comparison with other chemical propulsion motors, are the most important reasons for such interest. Moreover, throttle-ability and thrust variability on demand are additional advantages of this type of motor. In this paper, the result of an internal ballistic simulation of hybrid rocket motor in a zero-dimensional form is presented. Further to validate the code, an experimental setup was designed and manufactured. The simulation results are compared with the experimental data and good agreement is achieved. The effect of various parameters on the motor performance and on the combustion products is also investigated. It is found that increasing the oxidizer flow rate, increases the pressure and specific impulse of the motor; however, the slope of the specific impulse for the high flow rate case reduces. In addition, by increasing the combustion chamber pressure, the specific impulse is increased considerably. The initial diameter of the fuel port does not have significant effect on the pressure chamber and on the specific impulse. Addition of a percentage of an oxidizer like ammonium perchlorate to the fuel increases the specific impulse linearly.

scholarly journals Synthesis and Optimization of Chitosan Ceramic-Supported Membranes in Pervaporation Ethanol Dehydration

Membranes ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 119 ◽  
Author(s):  
Mahdi Nikbakht Fini ◽  
Sepideh Soroush ◽  
Mohammad Montazer-Rahmati
Keyword(s):  
Separation Factor ◽  
Low Cost ◽  
Chitosan Solution ◽  
Feed Water ◽  
Permeation Flux ◽  
Hybrid Membranes ◽  
Alumina Support ◽  
Membrane Performance ◽  
Chitosan Concentration ◽  
Angle Measurements

In the present work, ceramic-supported chitosan hybrid membranes were prepared for the pervaporation dehydration of ethanol. Mullite and combined mullite-alumina (50% alumina content) tubular low-cost ceramic supports were fabricated, and their influence on membrane performance was compared to a commercial α-alumina support. The membrane preparation parameters were different ceramic supports and the concentration of chitosan solution (varying from 2 wt.% to 4 wt.%). The supports and hybrid membranes were characterized by field emission scanning electron microscopy (FE-SEM) and contact angle measurements. The results show, with increasing chitosan concentration, the permeability decreases, and selectivity increases. It was also found that the separation factor decreases with increasing feed temperature and feed water content, while the permeation flux increases. The membrane that was coated on α-alumina support with a 3 wt.% chitosan concentration exhibited the best pervaporation performance, leading to a permeation flux and separation factor of 352 g·m−2·h−1 and 200 for 90 wt.% ethanol in feed at 60 °C, respectively.

scholarly journals Green Activated Magnetic Graphitic Carbon Oxide and Its Application for Hazardous Water Pollutants Removal

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 935 ◽  
Author(s):  
Lakshmi Prasanna Lingamdinne ◽  
Jong-Soo Choi ◽  
Yu-Lim Choi ◽  
Jae-Kyu Yang ◽  
Janardhan Reddy Koduru ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Low Cost ◽  
Reaction Medium ◽  
Carbon Oxide ◽  
Graphitic Carbon ◽  
Batch Adsorption ◽  
Ozone Oxidation ◽  
Fundamental Information ◽  
Pollutants Removal ◽  
Kinetics And Isotherms

Graphitic carbon oxide (GCO) and magnetic graphitic carbon oxide (MGCO) were prepared from sugar via optimized green activation by employing ozone oxidation, and applied to wastewater treatment. The maximal oxidation and adsorption yield of pollutants were achieved at pH 2.0−4.0, which is the optimized pH for ozone oxidation of GC to generate GCO. As-prepared GCO and MGCO were characterized using X-ray, infrared, and microscopic techniques. The MGCO has enough saturation magnetization (MS) of 41.38 emu g−1 for separation of the sorbent from the reaction medium by applying an external magnetic field. Batch adsorption of radioactive and heavy metals (Th(IV), Pb(II)), and a dye (methylene blue (MB)) using GCO and MGCO was evaluated by varying the adsorbent dose, equilibrium pH, contact time, initial metal and dye concentrations, and kinetics and isotherms. Adsorption kinetics and isotherm studies indicated that Th(IV), Pb(II), and MB adsorption were best described by pseudo-second-order kinetics and Langmuir isotherm with R2 (correlation coefficient) > 0.99, respectively. The maximum adsorption capacities for Th(IV), Pb(II), and MB were 52.63, 47.39, and 111.12 mg g−1 on GCO and 76.02, 71.94, and 76.92 mg g−1 on MGCO. GCO and MGCO are prospectively effective and low-cost adsorbents for ion removal in wastewater treatment. As prepared MGCO can be reused up to three cycles for Th(IV), Pb(II), and MB. This work provides fundamental information about the equilibrium adsorption isotherms and mechanisms for Th(IV), Pb(II), and MB on GCO and MGCO.

scholarly journals Construction of a comprehensive endovascular test bed for research and device development in mechanical thrombectomy in stroke

2020 ◽  
pp. 1-8 ◽  
Author(s):  
Adithya S. Reddy ◽  
Yang Liu ◽  
Joshua Cockrum ◽  
Daniel Gebrezgiabhier ◽  
Evan Davis ◽  
...  
Keyword(s):  
Flow Rate ◽  
Hydraulic System ◽  
Mechanical Thrombectomy ◽  
Low Cost ◽  
Quality Analysis ◽  
Test Bed ◽  
Vessel Occlusion ◽  
Physiological Flow ◽  
3D Printed ◽  
Device Interaction

OBJECTIVEThe development of new endovascular technologies and techniques for mechanical thrombectomy in stroke has greatly relied on benchtop simulators. This paper presents an affordable, versatile, and realistic benchtop simulation model for stroke.METHODSA test bed for embolic occlusion of cerebrovascular arteries and mechanical thrombectomy was developed with 3D-printed and commercially available cerebrovascular phantoms, a customized hydraulic system to generate physiological flow rate and pressure, and 2 types of embolus analogs (elastic and fragment-prone) capable of causing embolic occlusions under physiological flow.RESULTSThe test bed was highly versatile and allowed realistic, radiation-free mechanical thrombectomy for stroke due to large-vessel occlusion with rapid exchange of geometries and phantom types. Of the transparent cerebrovascular phantoms tested, the 3D-printed phantom was the easiest to manufacture, the glass model offered the best visibility of the interaction between embolus and thrombectomy device, and the flexible model most accurately mimicked the endovascular system during device navigation. None of the phantoms modeled branches smaller than 1 mm or perforating arteries, and none underwent realistic deformation or luminal collapse from device manipulation or vacuum. The hydraulic system created physiological flow rate and pressure leading to iatrogenic embolization during thrombectomy in all phantoms. Embolus analogs with known fabrication technique, structure, and tensile strength were introduced and consistently occluded the middle cerebral artery bifurcation under physiological flow, and their interaction with the device was accurately visualized.CONCLUSIONSThe test bed presented in this study is a low-cost, comprehensive, realistic, and versatile platform that enabled high-quality analysis of embolus–device interaction in multiple cerebrovascular phantoms and embolus analogs.

scholarly journals Low-Cost Alternative Biodiesel Production Apparatus Based on Household Food Blender for Continuous Biodiesel Production for Small Communities

2021 ◽  
Author(s):  
Wijittra Wongjaikham ◽  
Doonyapong Wongsawaeng ◽  
Vareeporn Ratnitsai ◽  
Manita Kamjam ◽  
Kanokwan Ngaosuwan ◽  
...  
Keyword(s):  
Flow Rate ◽  
Palm Oil ◽  
Catalyst Concentration ◽  
Low Cost ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Homogeneous Catalyst ◽  
Reaction Volume ◽  
Small Communities ◽  
Production Apparatus

Abstract Fatty acid methyl esters (FAMEs) are sustainable biofuel that can alleviate high oil cost and environmental impacts of petroleum-based fuel. A modified 1,200 W high efficiency fruit blender was employed for continuous transesterification of various refined vegetable oils and waste cooking oil (WCO) using sodium hydroxide as a homogeneous catalyst. The following factors have been investigated on their effects on FAME yield: baffles, reaction volume, total reactant flow rate, methanol-oil molar ratio, catalyst concentration and reaction temperature. Results indicated that the optimal conditions were: 2,000 mL reaction volume, 50 mL/min total flow rate, 1% and 1.25% catalyst concentration for refined palm oil and WCO, respectively, 6:1 methanol-to-oil molar ratio and 62 - 63oC, obtaining yield efficiency over 96.5% FAME yield of 21.14 ´ 10-4 g.J-1 (for palm oil) and 19.39 ´ 10-4 g.J-1 (for WCO). All the properties of produced FAMEs meet the EN 14214 and ASTM D6751 standards. The modified household fruit blender could be a practical and low-cost alternative biodiesel production apparatus for continuous biodiesel production for small communities in remote areas.

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