scholarly journals Primary Research of a New Zero-Liquid-Discharge Technology of Wet Flue Gas Desulfurization Wastewater by Low-Rank Heat from Flue Gas

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4259
Author(s):  
Xuan Yao ◽  
Man Zhang ◽  
Boyu Deng ◽  
Xinhua Yang ◽  
Hairui Yang
Keyword(s):  
Flue Gas ◽  
Ph Value ◽  
New Technology ◽  
Chemical Precipitation ◽  
Filter Press ◽  
Flue Gas Desulfurization ◽  
Low Rank ◽  
Market Demand ◽  
Liquid Discharge ◽  
High System

Wet flue gas desulfurization (WFGD) wastewater treatment is a key problem in coal-fired plants. Traditional chemical precipitation methods cannot reach zero-liquid discharge (ZLD). In this paper, a new technology using the low-rank heat from flue gas to concentrate the wastewater for ZLD is proposed. A scrubber was built to verify the concentrating process, and the characteristics of the concentrated water were analyzed. The concentrated water was neutralized by adding Ca(OH)2 to raise the pH value. The wastewater can be concentrated 10~25 times to reduce the flow rate. The characteristics of the concentrated wastewater were studied by dosing lime. Then, liquid and solids were separated by filter pressing, the liquid was mainly composed of CaCl2, which accounts for 73.6%. The sludge is composed of CaSO4 and Mg(OH)2, depending on the lime consumption of the dosing process. Finally, the filter liquor after the filter press was mixed with ash to reach zero liquid discharge, and the sludge could be burnt after mixing with the coal or disposed by third-part vendor. This technology is demonstrated in one 600 MW unit and shows a high system reliability. The clean water is recycled by the WFGD wastewater during the evaporation. Binding on the environmental policies and large market demand of the WFGD wastewater, this technology shows a great application prospect in the future.

scholarly journals Reusing effluent of flue gas desulfurization wastewater treatment process as an economical calcium source for phosphorus removal

2017 ◽  
Vol 76 (6) ◽  
pp. 1429-1435 ◽  
Author(s):  
Weixiao Dou ◽  
Zhen Zhou ◽  
Jiongjiong Ye ◽  
Rongwei Huang ◽  
Lu-Man Jiang ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Flue Gas ◽  
Ph Value ◽  
Chemical Precipitation ◽  
High Energy ◽  
Flue Gas Desulfurization ◽  
Wastewater Treatment Process ◽  
Capital Costs ◽  
Calcium Source ◽  
P Removal

Flue gas desulfurization (FGD) wastewater treatment by conventional neutralization, chemical precipitation and coagulation process removes most suspended solids and heavy metals, and provides an effluent rich in calcium, alkalinity and chloride, which obstructs its reclamation and reuse but is in favor of phosphorus (P) precipitation. The goals of this study were to investigate feasibility of reusing FGD effluent as a calcium source for P removal from P-rich wastewater. Results revealed that increasing the volumetric ratio between FGD effluent and P-rich wastewater achieved higher pH value and Ca/P ratio, and thus enhanced P removal efficiency to 94.3% at the ratio of 40%. X-ray diffraction and scanning electron microscope analysis of harvested precipitates showed that increasing pH from 8 to 10 induced the conversion of hydroxyapatite to tri-calcium phosphate, and then to whitlockite. This study demonstrated that for reusing FGD effluent for P removal was highly feasible, both technically and economically. This process not only saves the cost of precipitants for P removal, but also provides an economical alternative for current zero liquid discharge technology for FGD wastewater, which requires high energy consumption and capital costs.

Modelling Flue Gas Desulfurization Using Pyrolusite Pulp in a Jet Bubbling Reactor

2009 ◽  
Vol 610-613 ◽  
pp. 85-96 ◽  
Author(s):  
Jing Dong Zhao ◽  
Shi Jun Su ◽  
Nan Shan Ai ◽  
Xiao Fan Zhu
Keyword(s):  
Flue Gas ◽  
Ph Value ◽  
Scale Up ◽  
Absorption Efficiency ◽  
Flue Gas Desulfurization ◽  
Process Conditions ◽  
Gas Temperature ◽  
Transfer Coefficients ◽  
Set Up ◽  
So2 Absorption

A mathematical model for flue gas desulfurization using pyrolusite pulp in jet bubbling reactor (JBR) was described. Firstly, based on the concept of two stages mass balance with chemical reaction, two models were set up, for jet bubbling zone and rising bubble zone, respectively, according to the construction of JBR. The models consist of two coupling differential equations and were solved simultaneously by integral and separation of the variables. Then the SO2 absorption efficiency expression was developed, considering the great discrepancy existing between the gas-side mass transfer coefficients of the jet bubbling zone and gas bubble rising zone. The final expression associates SO2 absorption efficiency with process conditions and JBR structure parameters, which can give some instruction and guidance for the study of reactor operation process. Predicted results from the theoretical model, including effect of pH value of the pulp, flue gas temperature and inlet SO2 concentration of flue gas on SO2 absorption efficiency, were found to be in good agreement with experimental data obtained in a jet bubbling reactor. The model provides a basis for the process scale up and operating guide.

Experimental Study on Desulfurization Enhanced by Additive in Limestone-Gypsum FGD Process

2014 ◽  
Vol 675-677 ◽  
pp. 422-425
Author(s):  
Jun Xia Liu
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
High Efficiency ◽  
Ph Value ◽  
Flue Gas Desulfurization ◽  
Gas Flow Rate ◽  
Lime Solution ◽  
Desulfurization Efficiency ◽  
Technical Features ◽  
Hexanedioic Acid

This Paper introduced the research background and technical features of the simulative experiments in the laboratory with the sorbent of lime solution without lime particles. By means of the effects of various influencing factors on SO2 removal efficiency were studied carefully. These parameters include gas flow rate (G), inlet SO2 concentration, liquid-to-gas ratios, the height of the packing and the additive, at the same time menstruating the pH value of the liquid flowing from the tower. To improve desulfurization efficiency of limestone in the wet flue gas desulfurization (WFGD), effect of the hexanedioic acid additive on limestone desulfurization agent were studied. The result shows that this system has advantages of high efficiency, stable, low investment and low circulating cost. The result could give a reference to optimization and will be helpful in selecting desulfurization techniques.

Dissolution Rate of Limestone for Wet Flue Gas Desulfurization in the Presence of Citric Acid

2011 ◽  
Author(s):  
Rui-tang Guo ◽  
Wei-guo Pan ◽  
Xiao-bo Zhang ◽  
Jiang Wu ◽  
Jian-xing Ren
Keyword(s):  
Citric Acid ◽  
Dissolution Rate ◽  
Flue Gas ◽  
Ph Value ◽  
Flue Gas Desulfurization ◽  
Calcium Citrate ◽  
Inhibition Effect ◽  
Limestone Dissolution ◽  
Ph Stat ◽  
Stat Method

Dissolution rate of limestone for wet flue gas desulfurization in the presence of citric acid was measured by pH-stat method. It was found that limestone dissolution rate in the presence of citric acid was controlled by mass transfer. As can be seen from the experimental results, in the presence of citric acid, limestone dissolution rate increased with increasing stirring speed and reaction temperature. When pH value was greater than or equal to 5.5, due to the formation of calcium citrate, citric acid would inhibit the dissolution process of limestone. And the inhibition effect was more obvious at higher pH value.

Study on a New Technology of Flue Gas Desulfurization in Sintering Process

2013 ◽  
Vol 726-731 ◽  
pp. 2284-2290 ◽  
Author(s):  
Su Ping Wang ◽  
Xue Gong Bi ◽  
De Ming Weng
Keyword(s):  
Flue Gas ◽  
Raw Materials ◽  
New Technology ◽  
Sulfur Removal ◽  
Solid Particles ◽  
Flue Gas Desulfurization ◽  
Sintering Process ◽  
New Approach ◽  
Study Results ◽  
Operation Cost

In this paper, a new technology of sintering flue gas desulfurization is proposed. The principle is that some kind of additives is introduced into feed mix, the additives decompose into NH3in sintering process during heating, the NH3reacts with SO2gas to form ammonium sulphate solid particles, the particles are captured as dust by ESP, so the removal of SO2in sintering flue gas is achieved. The study results show that the concentration of SO2in sintering flue gas decreases gradually with the increase of additive amount, when the specific quantity of additive is 3.02kg per ton mix, the decreasing rate of SO2is up to 81.33%(mass). Since sintering dust must be recycled as raw materials, in order to solve the problem of flue gas SO2concentration is gradually increasing, the approach of increasing the amount of additive can be taken, or the dust is separately treated for sulfur removal before being used as raw sintering material. The new approach of reducing SO2emission in sintering flue gas has advantages of low investment, small occupation area and low operation cost. Moreover, the additive is inexpensive and readily available, so sintering cost is not increased obviously.

Study of Dual-Alkali on Sintering Flue Gas Desulfurization

2011 ◽  
Vol 393-395 ◽  
pp. 304-307
Author(s):  
Yu Zhu Zhang ◽  
Ying Xu
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Ph Value ◽  
Surface Active Agent ◽  
Active Agent ◽  
Development Trend ◽  
Flue Gas Desulfurization ◽  
Before And After ◽  
Selection Principles ◽  
Desulfurization Process

Combining with the characteristics and control methods of sintering flue gas, several common methods for flue gas desulfurization(FGD) and development trend of desulfurization technology were described in this paper. According to characteristics of sintering flue gas and selection principles, dual-alkali method was used in the FGD. Desulfurization process, basic principle and characteristics of the process were studied in detail. By contrast test, the effect of concentration of the desulfurization, flue gas flow and surface active agent on the desulfurization efficiency was investigated in detail through calculating the pH value of the solution before and after desulfurization reaction.

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