Ultra-low Emission Coal-fired Power Plants Research Articles

Removal and emission characteristics of hazardous trace elements in total and graded particulate matters: A case study of a typical ultra-low emission coal-fired power plant

Particulate matters (PMs) and hazardous trace elements (HTEs) emitted from coal-fired power plants (CFPPs) have raised serious environmental and human issues. Herein, total PMs and graded PMs including PM<1, PM1–2.5 and PM2.5–10 at the inlet/outlet of air pollution control devices (APCDs) were collected from a representative ultra-low emission (ULE) CFPP in China. The removal efficiencies of total PMs by selective catalytic reduction (SCR), electrostatic precipitator (ESP), wet flue gas desulfurization (WFGD) and wet electrostatic precipitator (WESP) were 0.40 %, 99.9 %, 38.1 % and 85.3 %, respectively. PM2.5–10 was robustly removed by WFGD, while PM<1 and PM1–2.5 were readily removed by WESP. The removal efficiencies of As, Cd, Cr and Pb in total PMs by APCDs followed an order: ESP > WESP > WFGD > SCR. SCR significantly decreased Se concentration by 42.8 %, contrasting to the removal of As, Cd, Cr and Pb (10.8–20.8 %). As, Cd, Cr, Pb and Se concentrations in graded PMs at the outlets of ESP, WFGD and WESP decreased with particle size increasing. All As, Cd, Cr, and Pb contents in PM<1, PM1–2.5 and PM2.5–10 at WFGD outlet increased, surpassing their analogues at ESP and WESP outlets. However, the concentration of Se declined in PM<1 at WFGD outlet. The atmospheric emission factors (EFs) of As, Cd, Cr, Pb and Se in the studied ULE CFPP were respectively 7.32, 1.27, 6.05, 122.5 and 6.42 mg/t, in line with Monte Carlo simulations. This study would not only provide a basis for emission control of PMs and HTEs in CFPPs, but also promote the improvement of respective environmental policy.

Variation of nitrate and nitrite in condensable particulate matter from coal-fired power plants under the simulated rapid condensing conditions

In this work, condensation temperature, H2O vapor, SO2, SO3 and NH3 were studied to explore the formation mechanism of nitrate ions (NO3−) and nitrite ions (NO2−) in condensable particulate matter (CPM) discharged by ultra-low emission coal-fired power plants. Some important results were obtained: (i) The concentration of NO3− and NO2− increased with the decrease of condensation temperature, and H2O vapor could also promote the formation of NO3− and NO2−. (ii) The effects of SO2 and SO3 varied at different saturated states of flue gas, which was caused by the redox reaction of SO2 and NOX or the formation of H2SO4. (iii) NH3 could promote the nucleation of NO3− and NO2−, and the promotion effect also existed in the existence of SO2 or SO3. It is worth mentioning that SO3 and SO2 might synergistically inhibit the formation of NO3− and NO2−, regardless of the presence of NH3. The research results would enrich peoples understanding of the chemical and physical characteristics of NO3− and NO2− in CPM and provide a basic reference for the control of CPM emitted from coal-fired power plants.

Study on the characteristics of sulfate ion in condensable particulate matter from ultra-low emission coal-fired power plants

The sulfate ion (SO42−) in condensable particulate matters (CPM) discharged by ultra-low emission coal-fired power plants has caused a series of environmental problems. In this work, condensation temperature, H2O, NOx and NH3 were investigated to elucidate the characteristics of SO42− under fast condensation. The results demonstrated that SO3 was a crucial component for the formation of SO42− in CPM, and the SO42− concentration increased with the increase of proportion of deposited H2SO4. The SO42− produced by heterogeneous reaction of SO2 could be enhanced in low temperature, and SO2 and SO3 could jointly promote the formation of SO42−. Furthermore, H2O vapor could also strengthen the formation of SO42−, which was caused by the Stefan flow. NH3 acted as the core, and the formation of SO42− was promoted. NOx could provide an acidic environment, which would interfere with the state of SO42− and even suppress the aqueous-phase oxidation of SO2. Finally, the formation of fine particles would aggravate the capture difficulty of CPM, which might help to explain the decrease of SO42− concentration in real flue gas. The results could provide basic guidance for improving the control of SO42− in CPM emitted from coal-fired power plants.

Speciation, bioaccessibility and human health risk assessment of chromium in solid wastes from an ultra-low emission coal-fired power plant, China

Chromium (Cr) in solid wastes from ultra-low emission (ULE) coal-fired power plants (CFPPs) could engender adverse effects on environment and human health. Hence, solid waste samples containing bottom ash, fly ash, gypsum and sludge were collected from a typical ULE CFPP in China to study the distribution, speciation, bioaccessibility and human health risk of Cr. The results showed that Cr was depleted in gypsum, whereas significantly enriched in bottom ash, fly ash and sludge comparing with feed coal. The ratios of Cr(VI) to total Cr in solid wastes were relatively low, but the increase of flow fractions in Cr chemical binding forms implied the deterioration of environmental stability. Based on the in vitro simulated digestion methods of solubility bioavailability research consortium (SBRC) and physiologically based extraction test (PBET), the bioaccessibility of Cr in the gastric and intestinal phases reached the highest values in either gypsum or sludge. After incorporating bioaccessibility in human health risk assessment, the carcinogenic risk (CR) within acceptable limits of Cr in solid wastes to adults and children was concluded, with the non-carcinogenic hazard quotient (HQ) was all within the safety threshold. The Monte Carlo model was applied to evaluate the uncertainty analysis of human health risk assessment at 5% and 95% confidence interval, and the fitting results were consistent with the calculation results of the carcinogenic and non-carcinogenic risk for adults and children. This study is expected to provide insights for the integration of bioaccessibility into the health risk assessment of Cr in solid wastes from ULE CFPPs, thus is conducive to the disposal of solid wastes and human health protection.

A typical 300 MW ultralow emission coal-fired power plant: source, distribution, emission, and control of polycyclic aromatic hydrocarbons

• The LLT-ESP presents the best effect on the control of PAHs. • The APCDs have selectivity for the removal of PAHs with different phases and ring numbers. • Blending coal species guides the source reduction technology of PAHs. • The concentration of PAHs is effectively reduced by adsorbent injection coupled with an LLT-ESP. Polycyclic aromatic hydrocarbons (PAHs) are one of the dominant contributors to toxic organic pollutants emitted from coal combustion. In this study, the PAHs and condensable particulate matter (CPM) were sampled from a 300 MW ultralow emission coal-fired power plant. The effect of air pollution control devices (APCDs) on PAHs migration regularity and the influence of coal species changes on the emission of PAHs were studied. Note that the APCDs have definite selectivity for the removal of PAHs with different phases and ring numbers. The low-low temperature electrostatic precipitator (LLT-ESP) presented the best removal effect on PAHs (PAHs in flue gas, 29.92%; PAHs in CPM, 94.76%). The concentrations of PAHs were reduced at the outlet of the furnace (PAHs in flue gas, decreased from 3.318 to 2.850 μg/Nm 3 ) and at the stack (PAHs in flue gas, decreased from 4.737 to 3.008 μg/Nm 3 ; PAHs in CPM, decreased from 0.554 to 0.429 μg/Nm 3 ) by replacing bituminous coal with blended coal (lower volatiles) as fuel. The adsorbent injection coupled with LLT-ESP had a preferable removal effect on the PAHs (decreased from 4.949 to 1.451 μg/Nm 3 ), which was nearly 40% higher than the efficiency without the spray adsorbent.

Synergetic removal characteristics of mercury for ultra-low emission coal-fired power plant

The synergetic mercury removal by flue gas treatment process in coal-fired power plants is widely accepted, but there is a lack of a corresponding model to describe mercury transformations. In this work, a model for mercury transformations is established in a flue gas treatment process model using Aspen Plus. The concentrations, mass flow rates, and normalized emission factors of mercury, NOX, particulate matters (PM), and SO2 are investigated in a 660 MW coal-fired power plant. The mercury oxidation efficiency of the selective catalytic reduction (SCR) unit is 56.9 %. The mercury removal efficiency of the electrostatic precipitator (ESP) and wet flue gas desulphurization (WFGD) units are 53.5 % and 34.4 %, respectively. The ultra-low emission system achieves 63.3 % removal of mercury. Approximately 53.5 % of mercury is retained in the fly ash. The emission factor of mercury is 0.0131 mg/kWh and increases to 0.0265 mg/kWh when the load decreases from 100 % to 50 %. The emission factors of PM, SO2 and NOX are 7.1, 97.1, and 142.9 mg/kWh at full load, and 10.9, 97.4, 150.0 mg/kWh at 50 % load, respectively. The proposed flue gas treatment process model is considered a feasible approach for quantitative evaluation of multi-pollutants emissions at plant level.

Soft sensing of SO2 emission for ultra-low emission coal-fired power plant with dynamic model and segmentation model

Static models, segmentation models and dynamic models for soft sensing of SO2 emission were developed based on the Ordinary Least Squares, Support Vector Regression, eXtreme Gradient Boosting, Random Forest and Neural Network algorithms with real operational data from a 1000 MW coal-fired power plant with ultra-low emission systems. The prediction results of test set show that static models are not suitable for modeling the desulfurization systems with complex condition and time-delay process. Thus, segmentation models and dynamic models were used to optimize the prediction accuracy. All the prediction performance of the nonlinear models was improved significantly with dynamic model, while the prediction performance of the linear model was improved with segmentation model. The dynamic Neural Network model with one hidden layer achieves the most accurate regression result (R2 = 70.4 %, RMSE = 1.95 mg/m3, MAE = 1.53 mg/m3). The results show the superiority of the dynamic Neural Network model over the other and the dynamic Support Vector Regression model perform second-best.

Study on the control of condensable particulate matter by spraying activated carbon combined with electrostatic precipitator

Condensable particulate matter (CPM) is a primary particulate matter that exists in the form of gas or vapor phase before discharge, but after discharge, it rapidly turns into a particulate substance due to cooling and dilution. The composition of CPM is very complex, and it poses a threat to the environment and human health. However, there is a lack of research on the control of CPM. Therefore, this study investigated the effects of activated carbon (AC) injection coupled with low-low temperature electrostatic precipitator on the adsorption of CPM in the flue gas of a 300 MW ultra-low emission coal-fired power plant. The sampling system was conducted according to ISO 23210–2009 and U.S. EPA method 202. Results shows that the adsorption removal efficiency of CPM by ACs ranged from 14% to 33%, and the adsorption removal effect of AC on inorganic components in CPM was better than that of organic components. AC had significant adsorption effects on Cl− and NH4+ but had weak adsorption effect on NO3− in CPM. AC with larger specific surface area, more abundant pore structure, and richer surface chemical functional groups has better adsorption effect on metal elements such as Na, Ca, Mg, K, and Al in CPM is better than that of Fe. As for the organic components in CPM, the adsorption effect of AC for esters was considerable, but its adsorption on organosilicon was limited.

Impact of ultra-low emission retrofitting on partitioning and emission behavior of chromium in a Chinese coal-fired power plant.

Due to its low vapor pressure, chromium (Cr) mostly emitted as fly ash particles (especially PM2.5) into environment in coal-fired power plants (CFPPs). The ultra-low emission (ULE) control technologies used in current CFPPs may be beneficial to reducing both the regular pollutants and hazardous trace elements (e.g., Cr), but the insight into the removal efficiency of Cr by different upgrading air pollution cleaning devices (APCDs) and the environmental stability of the Cr-bearing wastes produced from those APCDs in the ULE CFPPs has rarely reported. This study investigated and compared the distribution and emission characteristics of Cr in a Chinese CFPP before and after ULE, and the leaching behavior of Cr after ULE retrofitting in combustion byproducts was also revealed. The results showed that Cr was primarily captured in bottom and fly ashes (80.85%), followed by gypsum (0.02%) and sludge from wet electrostatic precipitator (WESP) (4.52×10-4%), with only 3.02×10-8% emitted into the atmosphere. Additional WESP had a large removal efficiency of Cr with the value of 92.04%, and the overall Cr removal efficiency of selective catalytic reduction (SCR) equipment, electrostatic precipitator (ESP), wet flue gas desulphurization (WFGD) system, and WESP equipped after ULE retrofitting was 99.99%. Notably, although the mass percentage of Cr in WESP sludge was negligible, the concentration of Cr in WESP sludge was 324.04mg/kg. The leaching concentrations of Cr in combustion byproducts were in the descending order: fly ash>WESP sludge>bottom ash>gypsum. The atmospheric emission factor of Cr in the studied power plant was 1.08mg/t coal, which was significantly lower than those of the CFPPs before ULE retrofitting. Therefore, the ULE retrofitting for CFPP was beneficial to reduce Cr emissions. More attention should be paid to the subsequent processing problem of solid combustion byproducts, especially the WESP sludge.

Technology development and cost analysis of multiple pollutant abatement for ultra-low emission coal-fired power plants in China

The implementation of ultra-low emission (ULE) limits (SO2: 35 mg/m3, NOx: 50 mg/m3, PM: 10 mg/m3) promoted the development of flue gas treatment technologies in China. Pollutant control technology development for Chinese coal-fired power plants was summarized and an analysis of the applicability and cost of pollutant control technologies was conducted. Detailed data were collected from 30 ultra-low emission coal-fired units across China. Based on a cost analysis model, the average unit power generation incremental costs were 0.0144 and 0.0095 CNY/(kW·hr) for SO2 and NOx control technologies, respectively. The unit power generation incremental cost of twin spray tower technology was 7.2% higher than that of dual-loop spray tower technology. The effect of key parameters on operating cost was analyzed. The unit power generation incremental cost increased because of increments in the electricity price for SO2 control technology and the price of the reductant in NOx control technology. With high sulfur content or NOx concentration, the unit power generation incremental cost caused by pollutant control increased, whereas the unit pollutant abatement cost decreased. However, the annual operating hours or load increased, thereby leading to a decline in unit power generation incremental cost and unit pollutant abatement cost.

Effect of WESP on Emission Characteristics of Condensable Particulate Matter from Ultra-low Emission Coal-fired Power Plants

In order to study the effect of wet electrostatic precipitators(WESP) on emission characteristics of condensable particulate matter (CPM) from ultra-low emission coal-fired power plants that are under different capacity conditions, a set of CPM sampling devices was built based on US EPA Method 202, and an ultra-low emission coal-fired power plant was detected. This study evaluated the emission level of the CPM from the flue gas of coal-fired power plants, the effects of different unit capacity conditions on the CPM emission concentrations, and the removal efficiency of WESP for different components of the CPM. The results suggested that the emission concentrations of the CPM from ultra-low emission power plants were 27.27 mg·m-3 and 28.71 mg·m-3under the conditions of 75% and 100% capacity, respectively. The removal efficiencies of WESP for the CPM were 35.59% and 27.59%, respectively. SO42- was the main component of water-soluble ions of the CPM. The proportion of SO42- in inorganic components of the CPM reached more than 65% under different capacity conditions. In addition, the removal efficiency of WESP for Cl-, K+, Ca2+, Mg2+, Na+, and other inorganic ions reached 30%-50%, but the mass concentrations of SO42- and NO3- increased.

Assessing the dry impinger method for condensable particulate matter from ultra-low emission coal-fired power plant measurement

The dry impinger method is commonly used for the determination of condensable particulate matter (CPM) emissions. The coil and chamber condenser is used to build different dry impinger methods for CPM sampling. The comparative analysis of coil and chamber condenser is performed in a laboratory experiment to evaluate the deviation caused by SO2. Results showed that the positive deviation caused by SO2 in the chamber condenser is lower than that in the coil condenser under the same sampling conditions, especially under high humidity flue gas. The CPM emission characteristics from Hanchuan coal-fired power plant (CFPP) determined by both dry impinger methods are also investigated as well. The CPM and its most water-soluble ions (e.g., F−, Cl−, NO3−, SO42−, Na+, Ca2+ and NH4+) measured by method #2 (chamber condenser) are higher than that of method #1 (coil condenser). In addition, the esters in the CPM also increased with the CPM concentrations. Based on above evidences, it can be inferred that the dry impinger method with chamber condenser, will be recommended as the appropriate method for measuring CPM emitted from stationary sources, especially under the high humidity flue gas conditions.

Distribution and emission characteristics of filterable and condensable particulate matter in the flue gas emitted from an ultra-low emission coal-fired power plant

Total particulate matter emitted from coal-fired power plants can be classified into filterable particulate matter (FPM) and condensable particulate matter (CPM). In this study, the FPM and CPM in the flue gas were sampled from a 300 MW ultra-low emission coal-fired power plant by the simultaneous sampling system, which was conducted according to ISO 23210-2009 and U.S. EPA method 202. The results show that the emission concentration of CPM rose from 5.15 mg/Nm3 to 7.19 mg/Nm3 at the stack when coal mixed with sludge. Almost all of the air pollutant control devices have a positive effect on the removal of CPM and FPM in the flue gas, except the influence of the selective catalytic reduction (SCR) denitration device on CPM. And the SCR denitration equipment increased the concentration of inorganic components of CPM in flue gas. The low-low temperature electrostatic precipitator had the most obvious removal effect on CPM and FPM, and the removal efficiency for FPM and CPM was more than 90% and 75% respectively. The organic fraction in CPM was mainly composed of hydrocarbons, esters, organosilicon, and other organics. In particular, the proportion of hydrocarbons and organosilicon was relatively high. In the case of co-combustion of sludge and coal, the concentration of CPM and FPM in flue gas increased as a whole, but the distribution trend of CPM and FPM was consistent with that of the non-combustion sludge and the distribution of organic components in CPM was almost the same.

Effect of wet flue gas desulfurization on the concentrations and component profiles of condensable particulate matter from ultralow emission coal-fired power plants

This study investigated effect of wet flue gas desulfurization (WFGD) on the concentrations and component profiles of condensable particulate matter (CPM). This research was carried out in two ultralow emission coal-fired power plants (CFPPs), which were equipped with pulverized coal furnaces (PC), in Hunan province, China. The CPM concentrations were measured following the US EPA Method 202. The stack emissions of filterable particulate matter (FPM) met the Chinese ultralow emission standards, and the CPM concentrations from CFPP A and B were respectively 12.12 and 17.64 mg/Nm3. In the WFGD system, the removal efficiencies of the FPM and CPM were respectively 80% and 91% in CFPP A, 83% and 81% in CFPP B. SO42− accounted for the largest fraction of the total detected water-soluble ions in the CPM. Alkanes were the main component of the organic fraction in the CPM, which accounted for 95% in CFPP A and 92% in CFPP B. The removal efficiency of inorganic components from the CPM in CFPP A and B were 81% and 92%, respectively, possibly because the water-soluble ions could be dissolved and removed in the slurry; however, due to the limited solubility of alkanes and esters, the removal efficiency of organic components from the WFGD in CFPP A and B were only 17% and 31%, respectively. The emission factors (EFs) of the CPM for CFPP A and B range from 0.090 to 0.979 kg/(t of coal).

Influence of Dry Sorbent Injection System on Emission Characteristics of Condensable Particulate Matter in Coal-fired Power Plant

To study the effect of dry sorbent injection (DSI) system on the emission characteristics of condensable particulate matter (CPM) in a 600MW unit of an ultra-low emission coal-fired power plant in China, the EPA Method 202A is used to sample the flue gas from its total exhaust. Through sample analysis, the CPM emission concentration and water-soluble ion composition corresponding to the two unit loads and whether the DSI is running are obtained. The results show that the use of DSI system reduces CPM emissions at 600MW and 300MW unit loads, and the CPM emission concentration is reduced by 32% and 9.7%, respectively. For the CPM reduction caused by DSI system under these two loads, SO4 2- and Cl− together contributed 65.7% and 87.3%, respectively. The DSI system achieves the removal of CPM mainly by removing the SO3 and HCl, which are gaseous precursors of SO4 2- and Cl− in CPM. At the same time, water-soluble ions are the main component of CPM. The analysis of its composition shows that the masses of NH4 +, Cl− and SO42- ions are relatively large, and they together account for 95.8%-96.8% of all water-soluble ions mass.

Arsenic emission and distribution characteristics in the ultra-low emission coal-fired power plant.

The characteristics of arsenic emission and distribution of a typical Chinese coal-fired power plant renovated with ultra-low emission technique have been studied. The results showed that arsenic concentration in coal was 5.72 mg/kg, and the arsenic emissions in fly ash, bottom ash, gypsum, flue gas, and wastewater were 489.12 g/h, 5.15 g/h, 1.14 g/h, 0.46 g/h, and 0.03 g/h, respectively, corresponding to the proportion of arsenic in fly ash, bottom ash, gypsum, flue gas, and wastewater of 98.63%, 1.04%, 0.23%, 0.09%, and 0.01%, respectively. About 87.61% of the gaseous arsenic was absorbed by catalysts used for selective catalytic reduction (SCR). Low-low temperature electrostatic precipitator (LLT-ESP) plays a key role in decreasing particulate arsenic. Wet flue gas desulfurization (WFGD) has positive effects on absorbing both gaseous and particulate arsenic. The removal efficiencies across the air pollution control devices follow the order of LLT-ESP > WFGD > SCR. The LLT-ESP can achieve a significant arsenic removal efficiency of 99.94%, resulting in quite low arsenic emission to the atmosphere. According to the calculated arsenic emission factor, the total emission amount of arsenic to the atmosphere from all Chinese coal-fired stations with ultra-low emission control technique in 2020 is estimated to be about 9.67-11.59 tons/year.

Field Studies on the Removal Characteristics of Particulate Matter and SOx in Ultra-Low Emission Coal-Fired Power Plant

In order to reduce the environmental smog caused by coal combustion, air pollution control devices have been widely used in coal-fired power plants, especially of wet flue gas desulfurization (WFGD) and wet electrostatic precipitator (WESP). In this work, particulate matter with aerodynamic diameter less than 10 μm (PM10) and sulfur oxides (SOx) have been studied in a coal-fired power plant. The plant is equipped with selective catalytic reduction, electrostatic precipitator, WFGD, WESP. The results show that the PM10 removal efficiencies in WFGD and WESP are 54.34% and 50.39%, respectively, and the overall removal efficiency is 77.35%. WFGD and WESP have effects on the particle size distribution. After WFGD, the peak of particles shifts from 1.62 to 0.95 μm, and the mass concentration of fine particles with aerodynamic diameter less than 0.61 μm increases. After WESP, the peak of particle size shifts from 0.95 to 1.61 μm. The differences are due to the agglomeration and growth of small particles. The SO3 mass concentration increases after SCR, but WFGD has a great influence on SOx with the efficiency of 96.56%. WESP can remove SOx, but the efficiency is 20.91%. The final emission factors of SO2, SO3, PM1, PM2.5 and PM10 are 0.1597, 0.0450, 0.0154, 0.0267 and 0.0215 (kg · t−1), respectively. Compared with the research results without ultra-low emission retrofit, the emission factors are reduced by 1~2 orders of magnitude, and the emission control level of air pollutants is greatly improved.

Soft Sensing of SO2 Emission for Ultra-Low Emission Coal-Fired Power Plant with Dynamic Model and Segmentation Model

Soft Sensing of SO2 Emission for Ultra-Low Emission Coal-Fired Power Plant with Dynamic Model and Segmentation Model

Removal characteristics of particulate matters and hazardous trace elements in a 660 MW ultra-low emission coal-fired power plant

Coal is the dominant energy source in China, and coal-fired power plant (CFPP) accounts for about half of coal consumption. However, air pollutant emissions from coal-fired power plants cause severe environmental and ecological problems. The most stringent regulations to limit air pollutant emissions from CFPP have been implemented in China since 2015. The ultra-low emission standards require that particulate matters (PMs) concentration from stack must not exceed 5 mg/Nm3. For exploring the emission characteristics of particulate matters and some trace elements, the field sampling test was carried out in a 660 MW ultra-low emission coal-fired power plant. It is equipped with low temperature economizer (LTE), electrostatic precipitators (ESP), wet flue gas desulfurization (WFGD), and wet electrostatic precipitator (WESP). The results showed that the mass removal efficiency of PM10 is about 80% in ESP and about 70% in WESP, in which most of them are PM2.5. The mass concentration removal efficiency of PM10 was 98.77% in ESP while that of PM2.5 is 98.58%. The mass concentration removal efficiency of PM10 was 63.43% in WESP while that of PM2.5 is 71.92%. At the same time, the trace elements on different particle sizes were analyzed. Manganese contents were found to be independent of the particle size. Cr, As and Pb are mainly enriched in the fine ash particles. In terms of the emission factors, Cr, As, Pb, and Mn are mainly in the fine particles.

SOx removal and emission characteristics of WFGD system applied in ultra-low emission coal-fired power plants

In this paper, SOX (SO2 and SO3) removal and emission characteristics of wet limestone-gypsum flue gas desulfurization (WFGD) are investigated based on the data collected from 95 ultra-low emission coal-fired power units. The study shows that the overall removal efficiency of single-absorber is above 97.5%, in which the SO3 removal efficiency is between 31% and 70%. When the inner structures are installed into the spray absorber, the correlation between the inlet SO2 concentration and SOX removal efficiency becomes more obvious, however, with a tray absorber, the maximum SO2 removal efficiency of double-absorber reaches 99.74%, in which the SO3 removal efficiency is between 27% and 81%. With a normal spray absorber, the higher inlet concentration, the higher removal efficiency it reaches, while with a tray absorber, the result is opposite. With a single-absorber, there is little correlation between flue gas temperature drop and SO2 removal efficiency. Large temperature drop harms the improvement of overall SO2 removal efficiency but is beneficial to SO3 removal. By the calculation of SOX emission performance model, average emission performances of SO2 and SO3 are acquired, which are about 90–107 mg/(kW·h) and 81–97 mg/(kW·h), respectively.