A robust and renewable solar steam generator for high concentration dye wastewater purification

Author(s):  
Xuan Wang ◽  
Kang Liu ◽  
Zubin Wang ◽  
Liping Heng ◽  
Lei Jiang

As an eco-friendly and sustainable technology, the solar-driven interfacial evaporation for water purification garners widespread attention. In the field of dye wastewater purification, some solar steam generators with catalytic degradation...

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2091
Author(s):  
Angela Spoială ◽  
Cornelia-Ioana Ilie ◽  
Denisa Ficai ◽  
Anton Ficai ◽  
Ecaterina Andronescu

During the past few years, researchers have focused their attention on developing innovative nanocomposite polymeric membranes with applications in water purification. Natural and synthetic polymers were considered, and it was proven that chitosan-based materials presented important features. This review presents an overview regarding diverse materials used in developing innovative chitosan-based nanocomposite polymeric membranes for water purification. The first part of the review presents a detailed introduction about chitosan, highlighting the fact that is a biocompatible, biodegradable, low-cost, nontoxic biopolymer, having unique structure and interesting properties, and also antibacterial and antioxidant activities, reasons for using it in water treatment applications. To use chitosan-based materials for developing nanocomposite polymeric membranes for wastewater purification applications must enhance their performance by using different materials. In the second part of the review, the performance’s features will be presented as a consequence of adding different nanoparticles, also showing the effect that those nanoparticles could bring on other polymeric membranes. Among these features, pollutant’s retention and enhancing thermo-mechanical properties will be mentioned. The focus of the third section of the review will illustrate chitosan-based nanocomposite as polymeric membranes for water purification. Over the last few years, researchers have demonstrated that adsorbent nanocomposite polymeric membranes are powerful, important, and potential instruments in separation or removal of pollutants, such as heavy metals, dyes, and other toxic compounds presented in water systems. Lastly, we conclude this review with a summary of the most important applications of chitosan-based nanocomposite polymeric membranes and their perspectives in water purification.


Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 156
Author(s):  
Manjing Lu ◽  
Jiaqi Wang ◽  
Yuzhong Wang ◽  
Zhengguang He

Chemical synthetic pharmaceutical wastewater has characteristics of high concentration, high toxicity and poor biodegradability, so it is difficult to directly biodegrade. We used acid modified attapulgite (ATP) supported Fe-Mn-Cu polymetallic oxide as catalyst for multi-phase Fenton-like ultraviolet photocatalytic oxidation (photo-Fenton) treatment with actual chemical synthetic pharmaceutical wastewater as the treatment object. The results showed that at the initial pH of 2.0, light distance of 20 cm, and catalyst dosage and hydrogen peroxide concentration of 10.0 g/L and 0.5 mol/L respectively, the COD removal rate of wastewater reached 65% and BOD5/COD increased to 0.387 when the reaction lasted for 180 min. The results of gas chromatography-mass spectrometry (GC-MS) indicated that Fenton-like reaction with Fe-Mn-Cu@ATP had good catalytic potential and significant synergistic effect, and could remove almost all heterocycle compounds well. 3D-EEM (3D electron microscope) fluorescence spectra showed that the fluorescence intensity decreased significantly during catalytic degradation, and the UV humus-like and fulvic acid were effectively removed. The degradation efficiency of the nanocomposite only decreased by 5.8% after repeated use for 6 cycles. It seems appropriate to use this process as a pre-treatment for actual pharmaceutical wastewater to facilitate further biological treatment.


Author(s):  
Mitch Hokazono ◽  
Clayton T. Smith

Integral light-water reactor designs propose the use of steam generators located within the reactor vessel. Steam generator tubes in these designs must withstand external pressure loadings to prevent buckling, which is affected by material strength, fabrication techniques, chemical environment and tube geometry. Experience with fired tube boilers has shown that buckling in boiler tubes is greatly alleviated by controlling ovality in bends when the tubes are fabricated. Light water reactor steam generator pressures will not cause a buckling problem in steam generators with reasonable fabrication limits on tube ovality and wall thinning. Utilizing existing Code rules, there is a significant design margin, even for the maximum differential pressure case. With reasonable bend design and fabrication limits the helical steam generator thermodynamic advantages can be realized without a buckling concern. This paper describes a theoretical methodology for determining allowable external pressure for steam generator tubes subject to tube ovality based on ASME Section III Code Case N-759-2 rules. A parametric study of the results of this methodology applied to an elliptical cross section with varying wall thicknesses, tube diameters, and ovality values is also presented.


Author(s):  
Akber Pasha

In recent years the combined cycle has become a very attractive power plant arrangement because of its high cycle efficiency, short order-to-on-line time and flexibility in the sizing when compared to conventional steam power plants. However, optimization of the cycle and selection of combined cycle equipment has become more complex because the three major components, Gas Turbine, Heat Recovery Steam Generator and Steam Turbine, are often designed and built by different manufacturers. Heat Recovery Steam Generators are classified into two major categories — 1) Natural Circulation and 2) Forced Circulation. Both circulation designs have certain advantages, disadvantages and limitations. This paper analyzes various factors including; availability, start-up, gas turbine exhaust conditions, reliability, space requirements, etc., which are affected by the type of circulation and which in turn affect the design, price and performance of the Heat Recovery Steam Generator. Modern trends around the world are discussed and conclusions are drawn as to the best type of circulation for a Heat Recovery Steam Generator for combined cycle application.


Author(s):  
Salim El Bouzidi ◽  
Marwan Hassan ◽  
Jovica Riznic

Nuclear steam generators are critical components of nuclear power plants. Flow-Induced Vibrations (FIV) are a major threat to the operation of nuclear steam generators. The two main manifestations of FIV in heat exchangers are turbulence and fluidelastic instability, which would add mechanical energy to the system resulting in great levels of vibrations. The consequences on the operation of steam generators are premature wear of the tubes, as well as development of cracks that may leak radioactive heavy water. This paper investigates the effect of tube support clearance on crack propagation. A crack growth model is used to simulate the growth of Surface Flaws and Through-Wall Cracks of various initial sizes due to a wide range of support clearances. Leakage rates are predicted using a two-phase flow leakage model. Non-linear finite element analysis is used to simulate a full U-bend subjected to fluidelastic and turbulence forces. Monte Carlo Simulations are then used to conduct a probabilistic assessment of steam generator life due to crack development.


2020 ◽  
Vol 261 ◽  
pp. 114410 ◽  
Author(s):  
Feng Gong ◽  
Wenbin Wang ◽  
Hao Li ◽  
Dawei (David) Xia ◽  
Qingwen Dai ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document