Experimental study on zero liquid discharge (ZLD) of FGD wastewater from a coal-fired power plant by flue gas exhausted heat

Fu, Jiangtao; Hu, Ning; Yang, Zhongqing; Wang, Li

doi:10.1016/j.jwpe.2018.10.005

Cited by 41 publications

(19 citation statements)

References 7 publications

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“…The spray evaporation of desulphurization wastewater includes two modes, one is the ue evaporation technology and the other is the evaporation tower technology. The ue evaporation technology is to spray atomized droplets into the main or bypass ue between air preheater and electrostatic precipitator (ESP), and make use of the hot ue gas to evaporate them (Fu et al 2018;Feng et al 2019;Ma et al 2020). Due to the low temperature of ue gas between air preheater and ESP, when the boiler load changes, it is easy to cause incomplete evaporation of desulfurization wastewater and result in corrosion of ue and equipment.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the treatment of desulfurization wastewater from coal-fired power plant by spray evaporation

Sun

Zhao

Feng

et al. 2022

Preprint

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The desulfurization wastewater in coal-fired power plants is difficult to treat due to its high salt concentration and complex composition. In this study, a pilot-scale evaporation tower system was built to treat the desulfurization wastewater by spray evaporation. The distribution characteristics of Cl- in wastewater evaporation process, the characteristics of solid evaporation products from desulfurization wastewater and the influence on the characteristics and removal effect of particulate matters in flue gas were investigated. The results show that the increase of salt content in desulfurization wastewater increased the mass concentrations of Cl- in the gas phase, outlet solid phase and bottom solid phase, but the proportions of it in three phases remained almost unchanged. The increase of flue gas temperature can improve the content of Cl- in the gas phase, while the increase of wastewater pH inhibited the formation of gaseous HCl. The solid evaporation products from desulfurization wastewater had prismatic crystal structure, which mainly included the sulfate and chloride salts, and the main elements in them were O, Na, Mg, S, Cl, K and Ca. Besides, the particle size of bottom solid phase was larger than that of outlet solid phase. For the particulate matters in flue gas, the spray evaporation of desulfurization wastewater can reduce the particle concentration, promote the particle agglomeration, reduce the number concentration of fine particles and improve the removal effect of PM10.

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Section: Introductionmentioning

confidence: 99%

Experimental study on the treatment of desulfurization wastewater from coal-fired power plant by spray evaporation

Sun

Zhao

Feng

et al. 2022

Preprint

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“…After chemical precipitation, concentration and clarification, spraying desulfurization wastewater into the flue duct and using exhaust flue gas heat for evaporation is an effective and economical technology [8,13,14]. Figure 1 shows the process of spray evaporation treatment of desulfurization wastewater [15]. Firstly, wastewater mixed with compressed air is atomized into droplets through an air-blast spray nozzle.…”

Section: Introductionmentioning

confidence: 99%

“…The FDG wastewater spray system can be operated in a continuous mode, and there are no negative effects on the equipment. The results showed that this technology is feasible [15]. Further, several numerical studies have also been carried out on FDG wastewater droplet evaporation to evaluate the thermal performance, and investigate the effect of design and operating parameters (position and number of nozzles, droplet size, flue gas temperature/flow rate, spray direction, etc.…”

Section: Introductionmentioning

confidence: 99%

Study on Spray Evaporation Treatment of Desulfurization Wastewater

Guo

Wang

et al. 2021

Coatings

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Limestone-gypsum wet flue gas desulfurization (WFGD) often produces a certain amount of wastewater with complex water quality and heavy metal pollution which should be treated properly before release. Spaying the desulfurization wastewater into flue duct and using exhausted flue gas heat for evaporation is a promising and economical technology for achieving zero wastewater discharge in thermal power plant. To enable a more in-depth understanding on evaporation of FGD wastewater spray, a visual wind tunnel test rig based on the atomized droplet laser measuring system was built to reveal the impact factors on droplet thermal-fluid behavior. The dominant impact factors such as compressed air pressure and flow rate in air-blast spray nozzle, hot air temperature and velocity in the evaporation tunnel were analyzed to discuss the droplet size distribution and evaporation performance through alternating operate condition. A discrete mathematical model that combines both Eulerian and Lagrangian framework was established to validate the experiment result. It is concluded that introducing high pressure compressed air into the nozzle can contribute to the dispersion of droplets and enhance the evaporation rate. Proper flow rate in spray nozzle is required to avoid incomplete droplets evaporation. Air temperature and velocity in the evaporation tunnel apply positive impact on droplet size distribution and evaporation performance. Numerical simulation results of both dominant factors impact on evaporation behavior and total evaporation rate showed consistency with the experimental outcome.

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“…The atomized droplets are quickly evaporated by the high-temperature flue gas to achieve a near zero emission. As shown in Figure 1, the FGD wastewater is atomized into droplets with the help of compressed air through the nozzle and injected into the flue duct tail of the boiler [10]. Then the wastewater is evaporated instantaneously due to absorbing the exhaust heat from flue gas.…”

Section: Introductionmentioning

confidence: 99%

“…However, the droplets evaporation is a nonlinear, multi-factor effected and complex process. Therefore, the researchers studied the spray evaporation from different perspectives by both experiment [10,[12][13][14] and numerical simulation [15][16][17][18][19][20]. Deng et al [15] investigated how the nozzle position arrangement and the flue gas temperature effected the evaporation through the computational fluid dynamic simulation methods.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation on Double-nozzle Spray Evaporation of Desulfurization Wastewater

Hong¹,

Feng²,

Xiao³

et al. 2021

Preprint

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To achieve the near zero emission of wastewater in the flue gas desulfurization (FGD) system in coal-fired power plant and better utilize the exhaust heat from flue gas, a feasible technology of spraying FGD wastewater in the flue duct for evaporation is discussed in the present study. A full-scale influencing factor investigation on the wastewater droplet evaporation performance is established under the Eulerian-Lagrangian model numerically. The dominant factors, including the characters of wastewater droplets, flue gas and the spray nozzles were analyzed under different conditions, respectively. Considering the multiple factors and conditions in the process, a Least-Square support vector machine (LSSVM) model is introduced to predict the evaporation rate based on the numerical results. Conclusions are made that the flue gas temperature and droplet diameter are of great importance in the evaporation process. The spray direction of droplet parallel with the flue gas flow direction is profitable for the dispersion of droplet, resulting the maximal evaporation rate. A double-nozzle arrangement optimized with relatively small flow rate is recommended. The LSSVM model can accurately predict the evaporation rate using the numerical results with different conditions.

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Experimental study on zero liquid discharge (ZLD) of FGD wastewater from a coal-fired power plant by flue gas exhausted heat

Cited by 41 publications

References 7 publications

Experimental study on the treatment of desulfurization wastewater from coal-fired power plant by spray evaporation

Experimental study on the treatment of desulfurization wastewater from coal-fired power plant by spray evaporation

Study on Spray Evaporation Treatment of Desulfurization Wastewater

Numerical Simulation on Double-nozzle Spray Evaporation of Desulfurization Wastewater

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