scholarly journals Study on the preparation and properties of talcum-fly ash based ceramic membrane supports

2020 ◽  
Author(s):  
Chao Cheng ◽  
Hongming Fu ◽  
Heng Zhang ◽  
Haiping Chen ◽  
Dan Gao

Abstract Ceramic membrane method for moisture recovery from flue gas of thermal power plants is of considerable interest due to its excellent selection performance and corrosion resistance. However, manufacturing costs of commercial ceramic membranes are still relatively expensive, which promotes the development of new methods of preparing low-cost ceramic membranes. In this study, a method for the preparation of porous ceramic membrane supports is proposed. Low-cost fly ash from power plants is the main material of the membrane supports, and talcum is the additive. The fabrication process of the ceramic membrane supports is described in detail. The properties of the supports were fully characterized, including surface morphology, phase composition, pore diameter distribution and porosity. Corrosion resistance and mechanical strength of the supports were measured. The obtained ceramic membrane support displays a pore size of about 5 µm and porosity of 37.8%. Furthermore, the water recovery performance of the supports under different operating conditions was experimentally studied. The experimental results show that, the recovered water flux varies with operating conditions. In the study, the maximum recovered water flux reaches 5.22 kg/(m2·h). The findings provide a guidance for the ceramic membrane supports application of water recovery from flue gas.

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 207
Author(s):  
Chao Cheng ◽  
Hongming Fu ◽  
Jun Wu ◽  
Heng Zhang ◽  
Haiping Chen

Ceramic membrane method for moisture recovery from flue gas of thermal power plants is of considerable interest due to its excellent selection performance and corrosion resistance. However, manufacturing costs of commercial ceramic membranes are still relatively expensive, which promotes the development of new methods for preparing low-cost ceramic membranes. In this study, a method for the preparation of porous ceramic membrane supports is proposed. Low-cost fly ash from power plants is the main material of the membrane supports, and talcum is the additive. The fabrication process of the ceramic membrane supports is described in detail. The properties of the supports were fully characterized, including surface morphology, phase composition, pore diameter distribution, and porosity. The mechanical strength of the supports was measured. The obtained ceramic membrane supports displays a pore size of about 5 μm and porosity of 37.8%. Furthermore, the water recovery performance of the supports under different operating conditions was experimentally studied. The experimental results show that the recovered water flux varies with operating conditions. In the study, the maximum recovered water flux reaches 5.22 kg/(m2·h). The findings provide a guidance for the ceramic membrane supports application of water recovery from flue gas.


Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 711
Author(s):  
Wan Fan ◽  
Dong Zou ◽  
Jingrui Xu ◽  
Xianfu Chen ◽  
Minghui Qiu ◽  
...  

Support is a necessary foundation for ceramic membranes to achieve high performance. Finding the optimum balance between high performance and low cost is still a significant challenge in the fabrication of ceramic supports. In this study, low-cost fly ash-based ceramic supports with enhanced performance were prepared by the addition of bauxite. The pore structure, mechanical strength, and shrinkage of fly ash/bauxite supports could be tuned by optimizing the bauxite content and sintering temperature. When the sintering temperature and bauxite content were controlled at 1300 °C and 40 wt%, respectively, the obtained membrane supports exhibited a high pure water permeance of approximately 5.36 m3·m−2·h−1·bar−1 and a high bending strength of approximately 69.6 MPa. At the same time, the optimized ceramic supports presented a typical mullite phase and excellent resistance to acid and alkali. This work provides a potential route for the preparation of ceramic membrane supports with characteristics of low cost and high performance.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Haiping Chen ◽  
Xiangsheng Li ◽  
Jiadi Wei ◽  
Yijun Feng ◽  
Dan Gao

In this paper, the manufacturing process of microceramic membrane is summarized. The main material of this membrane is fly ash which can reduce the sintering temperature and save the costs. The coal ash ceramic membrane (CACM) was characterized by XRD, SEM, and mercury intrusion method. The results show that the mullite phase formed by CACM at the sintering temperature of 1250°C has morphology and structural characteristics similar to the commercial microceramic membrane. The membrane surface is uniform and dense, without cracks; the pore diameter is 1–4 μm, and the porosity is 26.6%. Furthermore, the CACM and CMCM were compared at the aspects of water and heat recovery performance using flue gas. The experiment indicated that when the flue gas temperature was 50–85°C, the water recovery performance of these two kinds of membrane was similar. Also, the heat transfer capability of the coal ash ceramic membrane was close to that of the commercial microceramic membrane when the temperature range of flue gas was controlled between 50°C and 70°C. When the temperature of flue gas reaches 80°C, the heat transfer performance of the commercial ceramic membrane is better, and the difference of heat recovery between these two kinds of membranes is 19.3%. In general, the CACM and CMCM have similar mass transfer performance, and the heat transfer efficiency of CACM is lower than that of CMCM, but the costs of CACM is much lower than that of CMCM which has a good research prospect in the future.


Author(s):  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang

Low grade waste heat and water recovery using ceramic membrane, is an emerging technology which helps to increase the efficiency of boilers and gas or coal combustors in various industrial processes and conventional power plants. The tube wall of a Transport Membrane Condenser (TMC) based heat exchanger is made of a nano-porous material with high membrane selectivity which is able to extract condensate water from the flue gas in the presence of other non-condensable gases (i.e. CO2, O2 and N2). In this work, a numerical study has been carried out to investigate the effects of transversal pitches of the TMC bundle tubes on the performance of a TMC based cross flow heat exchanger. A simplified multi-species transport model is used to investigate the heat and mass transfer characteristics of a condensing combustion flue gas in a crossflow transport membrane tube bundle. Various transversal (0.4”–0.6”) and longitudinal (0.4”–0.8”) pitches were used. The numerical results revealed that the effect of transversal pitches on the outlet parameters are more pronounced.


2010 ◽  
Vol 72 ◽  
pp. 105-118 ◽  
Author(s):  
Enrico Drioli ◽  
Adele Brunetti ◽  
Giuseppe Barbieri

Today, CO2 capture from e.g. flue gas has becoming an emerging opportunity for membrane gas separation. The flue gas coming out from power plants contains about 10-15% CO2, which should be separated before its sequestration. The most used membranes for this application are polymeric but they cannot be used at a high temperature. The flue gas exits at ca. 200°C, depending on the specific locations in the plant and, thus, it is highly desirable to separate it at high temperature. An alternative class to polymeric membranes is represented by the ceramic one which comprises zeolites, carbons, silica, perovskites membranes, that exhibit high fluxes and thermal resistance. However, a great challenge is to fabricate them as thin layers, avoiding formation of cracks that compromise the separation. Today, new solutions are in progress for the production of ceramic membrane able to overcome these limitations. For example, hybrid membranes able to combine the properties of different materials are proposed. Moreover, new works are done on mixed-matrix membranes, comprising of a molecular sieve guest phase dispersed in a polymer host matrix [3] which combines the advantage offered by the two materials. This work proposes an overview on the main applications of ceramic membranes in CO2 capture processes.


2020 ◽  
Vol 15 (2) ◽  
pp. 416-425
Author(s):  
Sun Chuanwen ◽  
Wang Haiqiao ◽  
Yu Qi ◽  
Chen Shiqiang ◽  
Li Xun ◽  
...  

Abstract The flux performance of ceramic membranes is the basis for their efficient use. To study ceramic membrane flux variation, different filtration operating conditions were tested and the functional relationship between the membrane's clean water flux and the operating pressure within a given range obtained. The membrane's critical pressure and flux were determined by using pressure increments, and the flux variation law under different pressures determined experimentally. Analysis of the flux law and the membrane parameters enabled establishment of the flux model of filtration process and a model of flux stabilization after the deposition layer formed. The applicability of the model was proved by comparing and verifying the experimental data.


TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 65-78 ◽  
Author(s):  
W.B.A. (SANDY) SHARP ◽  
W.J. JIM FREDERICK ◽  
JAMES R. KEISER ◽  
DOUGLAS L. SINGBEIL

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.


2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.


2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Maya Livshits ◽  
Abraham Kribus

Solar heat at moderate temperatures around 200 °C can be utilized for augmentation of conventional steam-injection gas turbine power plants. Solar concentrating collectors for such an application can be simpler and less expensive than collectors used for current solar power plants. We perform a thermodynamic analysis of this hybrid cycle, focusing on improved modeling of the combustor and the water recovery condenser. The cycle's water consumption is derived and compared to other power plant technologies. The analysis shows that the performance of the hybrid cycle under the improved model is similar to the results of the previous simplified analysis. The water consumption of the cycle is negative due to water production by combustion, in contrast to other solar power plants that have positive water consumption. The size of the needed condenser is large, and a very low-cost condenser technology is required to make water recovery in the solar STIG cycle technically and economically feasible.


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