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Kucha was a small country once existed in the western border of China. Its famous Kizil Caves represents the importance of Buddhism to this country. This research focuses on the Kucha donor images found in some of the Kizil Caves, mainly two group of donors from cave No. 199 and No. 205. The dates, traits of clothing and “tipping toe” standing posture, and identity of these donors are argued and discussed, and they are compared to Sogdian, Bactrian, Persian, and Roman artworks that share similar clothing style or standing posture. Historical evidence is then presented throughout the paper to prove that the similar clothing style and standing posture between Kucha donors and foreign figures reflect cultural connections across the Eurasian continent, on the Silk Road. The paper also explains how the “tipping toe” standing posture is a shared artistic motif but is interpreted and used differently across cultures, thus leading to the author attempting to answer the question: why these Kucha donors were drawn in the Kizil Buddhist Caves. The research mainly uses articles and books written by professional scholars, with the support of some primary texts as historical evidence. Additional archaeological discoveries and art history visual analysis are applied to aid the conclusion of this paper.

In order to obtain a deep insight into the N2O formation mechanism in a fluidized bed, density functional theory was used to investigate the interaction between char(N) and NO at a molecular level. Three key influencing factors for the formation of N2O, namely, active sites, nitrogen status, and oxygen molecules, were taken into study. The geometric structures, electron distribution characteristics, and reaction paths were optimized and calculated. The outer orbital electron properties of char(N) and NO indicate that NO acts as an oxidizer, which tends to abstract electrons from char(N) during the char(N)-NO interaction. A stable N2O molecule has a singlet state and presents as a linear molecular structure. The chemisorption on the char surface will weaken the bond energy of NO from 620 to 94.1 kJ/mole, which promotes the catalytic reduction of NO. Active sites on the char surface benefit the reduction of NO to N2, rather than N2O, which indicates that excessive high temperatures will inhibit the production of N2O. The combination of pyridine nitrogen and NO to form N2O needs to overcome a much higher energy barrier of 357.4 kJ/mole. The initial chemisorption of oxygen molecules on the char surface will promote the formation of N2O by lowering the dissociation energy of N2O from the char surface as well as exposing nitrogen to the char surface.

CWF19L1 is responsible for spinocerebellar ataxia, autosomal recessive 17, which presents with cerebellar ataxia, and atrophy. Here, we report novel compound heterozygous variants of CWF19L1 in a Chinese family with progressive ataxia and mental retardation of unknown etiology by analyzing clinical characteristics and genetic variations.Clinical profiles and genomic DNA extracts of family members were collected. Whole-exome and Sanger sequencing were performed to detect associated genetic variants. Pathogenicity prediction and conservation analysis of the identified variants were performed using bioinformatics tools.We identified heterozygous variants at the invariant +2 position (c.1555_c.1557delGAG in exon 14 and c.1070G T in exon 11) of the CWF19L1 gene. Two novel heterozygous variants of the CWF19L1 gene were identified in the CWF19L1 gene associated with autosomal recessive cerebellar ataxia.Our results suggest that CWF19L1 variants may be a novel cause of recessive ataxia with developmental delay. Whole-exome sequencing is an efficient tool for screening variants associated with the disease. This case report may help diagnose and identify the causes of other ataxias, leading to novel therapies, especially in China. This finding enriches the variant spectrum of the CWF19L1 gene and lays the foundation for future studies on the correlation between genotype and phenotype.

Terminal or interstitial deletion of chromosome 2q is rarely reported but clinically significant, which can result in developmental malformations and psychomotor retardation in humans. In the present study, we analyzed this deletion to comprehensively clarify the relationship between phenotype and microdeletion region.We collected clinical records of the fetus and summarized patient symptoms. Subsequently, genomic DNA was extracted from fetal tissue or peripheral blood collected from parents. In addition, whole-exome sequencing (WES) and copy number variation sequencing (CNV-seq) were performed.The fetus presented a previously unreported interstitial deletion of 2q24.3-q32.1. WES and CNV-seq revealed a de novo 18.46 Mb deletion at 2q24.3-q32.1, a region involving 94 protein-coding genes, including HOXD13, MAP3K20, DLX1, DLX2, SCN2A, and SCN1A. The fetus had upper and lower limb malformations, including camptodactyly and syndactyly, along with congenital cardiac defects.Herein, we report a fetus with a novel microdeletion of chromosome 2q24.3-q32.1, likely a heterozygous pathogenic variant. Haploinsufficiency of HOXD13 might be related to limb deformity in the fetus.

The effect of self-reactivation on the CO2 capture capacity of the spent calcium based sorbent was investigated in a dual-fixed bed reactor. The sampled sorbents from the dual-fixed bed reactor were sent for XRD, SEM and N2 adsorption analysis to explain the self-reactivation mechanism. The results show that the CaO in the spent sorbent discharged from the calciner absorbs the vapor in the air to form Ca(OH)2 and further Ca(OH)2·2H2O under environmental conditions, during which process the CO2 capture capacity of the spent sorbent can be self-reactivated. The microstructure of the spent sorbent is improved by the self-reactivation process, resulting in more porous microstructure, higher BET surface area and pore volume. Compared with the calcined spent sorbent that has experienced 20 cycles, the pore volume and BET surface area are increased by 6.69 times and 56.3% after self-reactivation when φ = 170%. The improved microstructure makes it easier for the CO2 diffusion and carbonation reaction in the sorbent. Therefore, the CO2 capture capacity of the spent sorbent is enhanced by self-reactivation process. A self-reactivation process coupled with calcium looping process was proposed to reuse the discharged spent calcium based sorbent from the calciner. Higher average carbonation conversion and CO2 capture efficiency can be achieved when self-reactivated spent sorbent is used as supplementary sorbent in the calciner rather than fresh CaCO3 under the same conditions.

In order to have a deep insight into the NO formation mechanism during oxy-fuel combustion, density functional theory (DFT) was used to investigate the interaction between char(N) and CO2 at molecular level. The geometric structures, orbital electron distribution properties and reaction paths were calculated and optimized. The outer orbital electron properties of char(N) and CO2 indicate that CO2 acts as the oxidizer, which tends to attract electrons from char(N) during char(N)-CO2 interaction. The geometries and Mulliken properties of three initial chemisorption intermediates indicate that char(N) may mainly undergo two oxidation/gasification paths: one is carbon atom oxidation by CO2 to form CO via initial chemisorption structure of IM1. The other is nitrogen atom combination with oxygen atom and further to be oxidized to form NO via initial chemisorption structure of IM2. The initial chemisorption reactions of CO2 on char(N) surface are exothermic reactions and take place spontaneously at the operation temperature during oxy-fuel combustion. According to the reaction energy barriers and kinetic analysis, path 1 and path 2 have the comparative probability during char(N)-CO2 interaction to produce CO and NO. Nevertheless, NO produced in path 2 will further be in-situ reduced by CO over char surface, which will lead to low NO concentration in flue gas during oxy-fuel combustion.

A novel two-stage gasifier, consisting of a fluidized bed gasifier and a swirl-melting furnace, was proposed and built to gasify biomass with low ash melting temperatures into clean fuel gas. Improvements of the two-stage gasification in gas upgrading, tar removal and ash separation were confirmed by characteristic analysis of gas, tar, ash and slag. Influence of equivalence ratio (ER), oxygen distribution and gasifying agent were assessed for process optimization. Refined gas with a LHV up to 11.1 MJ/Nm3 and a tar content lower than 1 g/Nm3 was produced. Ash was completely vitrified with a high conversion of fixed carbon and volatile, resulting in a cold gas energy fraction of approximately 80%. Increasing ER promoted gas production but limited energy conversion efficiency and gas LHV. Proper oxygen distribution among the two stages was beneficial to decrease energy loss and increase gas quality. Increasing oxygen percentage of gasifying agent enhanced combustible gas content and improved overall gasification efficiency.

This research focuses on the relationship between people from the Sogdian Civilization and the city Dunhuang, including the Sogdians’ different identities when they arrived at Dunhuang, such as ambassadors, guests, Zhi Zi, and merchants. The Sogdians have played a significant role in the material and cultural exchanges on the Silk Road since the Western Han Dynasty, yet seldom do people know or learn about the Sogdian Civilization. Therefore, the purpose of this essay is to inform people about the Sogdians’ nonnegligible contribution and mutual impact on Chinese history and culture. The paper mainly uses quotations from Chinese historical records and articles written by modern scholars, with some sources related to archaeological discoveries and methods.

As the hazardous solid waste from alumina production, red mud (RM) is often used in the preparation of slurry or catalyst, but rarely considered for in-situ desulfurization of fluidized bed. In this paper, an experimental study was conducted on a lab-scale circulating fluidized bed (CFB) combustor to explore the feasibility of RM replacing limestone for in-situ desulfurization, from the perspectives of efficiency, combustion stability, CaO activity, deposition, NOx emission and operation cost. Although the adopted limestone showed better performance under most working conditions, the highest RM desulfurization efficiency still reached over 94% at 900 °C bed temperature and 20% blending ratio. Better combustion stability could be achieved at 900 °C and no more than 6.11% RM blending. The increase of RM addition had opposite effect on carbon content in bottom ash and fly ash, as well as the SO2 and NOx emissions whatever the bed temperature was. Compared with Zhundong coal, no severe ash deposition was observed at cyclone outlet, but the ash sintering got much worse at the upper furnace. The results demonstrated the feasibility to adopt RM directly as SO2 sorbents during CFB combustion, and achieved the dual effects of SO2 reduction and resource recovery of RM.

Natural iron ore as an oxygen carrier for chemical looping combustion (CLC) has recently attracted increasing attention. However, low fuel conversion efficiency is the major issue for the CLC process based on iron ore. The unconverted gaseous fuel causes energy loss and degrades CO2 purity. Based on the technology of interconnected fluidized bed, a new 2 kW CLC reactor was constructed with a two-stage fuel reactor. Staging oxidization of fuel was proposed in the special fuel reactor to promote fuel conversion. The fuel oxidation primarily occurs in the 1st stage fuel reactor, and the remaining unconverted combustible gas is further oxidized by fresh oxygen carrier in the 2nd stage fuel reactor. This CLC reactor was tested using an Australian iron ore as oxygen carrier and syngas and CH4 as gaseous fuels, respectively. The staging oxidization of gaseous fuel in this new configuration was evaluated by comparing with the results from a 1 kW reactor with one stage fuel reactor. For the syngas tests, fuel conversion efficiency in the 2 kW reactor maintained between 92.9% and 98.3%, while that in the 1 kW reactor maintained at only about 80%. For the CH4 tests with thermal power input of 1–2 kW, up to 92.9% CH4 was converted and CO2 yield reached around 88% at 980 °C. Finally, the oxygen carrier particles were characterized by XRD and SEM. Overall, staging oxidation of fuel is an effective method to enhance fuel conversion when using a Fe-based oxygen carrier.

In order to analyze the effect of the air volume on the combustion side and the non-uniformity of pulverized coal on the temperature distribution of the boiler outlet flue gas, and then analyze the thermal deviation characteristics of the steam heating surface, the following five different working conditions are calculated and analyzed in a 660MW boiler. Results show that the deviation of pulverized coal content of each burner and the deviation of primary air volume are the important factors that cause the temperature deviation of flue gas outlet in the furnace. Therefore, it is an important way to improve the temperature distribution and reduce the thermal deviation of flue gas outlet by improving the uniform combustion and air distribution of the burner in the furnace.

Lignocellulose oxidative degradation at low temperature is an important question in fire disaster and biomass utilization. Experimental and theoretical methods were used to investigate the initial stage of cellulose degradation under inert and oxidative atmosphere. TG-FTIR results show that the initial degradation and peak temperatures were lower in oxidative atmosphere. CO2 became the dominant component under oxidative atmosphere, which was attributed to the oxidation of carbon element. Oxygen promoted the formation of acids and aldehydes (-C O) but decreased the yields of alcohols/ethers (-C-O-). Density functional theory calculation results show that thermal cleavage of glucosidic bond is endothermic reaction. The chemisorption of oxygen with reactive cellulose radical released a great amount of heat that drove cellulose pyrolysis to an exothermic process. The formation of lactone structure is a kind source of CO2. Experimental and theoretical results agree with each other well and a possible cellulose oxidative pyrolysis pathway was put forward.

Mg-stabilized carbide slag (MSCS) was fabricated with carbide slag, magnesium nitrate hydrate and a by-product of biodiesel from transesterification by combustion, and was used as a CO2 sorbent in calcium looping cycles. The cycled MSCS containing a ratio of CaO to MgO of 80 : 20 from the calcium looping cycles (i.e. carbonation/calcination cycles) for CO2 capture was subsequently used as an HCl sorbent. The HCl capture performance of the cycled MSCS which had experienced repetitive CO2 capture cycles using calcium looping was investigated in a triple fixed-bed reactor. The reaction products of the cycled MSCS after HCl absorption are CaClOH, CaO, and MgO. MgO is an inert support. The cycled MSCS reaches the highest HCl capture capacity at 750 °C. The number of CO2 capture cycles increases the effect of chlorination temperature on the HCl capture capacity of the cycled MSCS. The HCl capture capacity of the cycled MSCS drops slightly with the number of CO2 capture cycles. The HCl capture capacity of the MSCS which has undergone 10 CO2 capture cycles can retain 0.21 g HCl/g sorbent, which is about 1.7 times as high as that of the carbide slag. The presence of CO2 leads to a reduction in the HCl capture capacity of the cycled MSCS. MSCS can maintain a more stable microstructure due to the presence of MgO during the repetitive CO2 capture cycles. The cycled MSCS from the CO2 capture cycles exhibits a more porous structure than the cycled carbide slag, especially in the pore size range of 2–10 nm in diameter, which benefits HCl capture. Therefore, the cycled MSCS from CO2 capture cycles using calcium looping appears promising to remove HCl.

Zedoary turmeric oil, a plant extract currently in clinical use, may provide potent pharmacological actions such as liver injury. In the previous study, to improve the in vivo absorption of ZTO and produce a high oral bioavailability, chitosan was employed to prepare sustained-release microspheres containing ZTO. In this study, a portability liver cancer model of rats was established successfully to compare the pharmacodynamic of ZTO microspheres and injection. In vitro results showed that microspheres had almost uniformly spherical shapes and were well dispersed by a relatively dynamic stable system. In vivo, compared with the control group, all ZTO microspheres groups resulted in growing inhibition of walker-256 cells transplanted solid tumor and the obvious controlled tumor size. At the same dose, ZTO microspheres suggested a better effect. The data showed that three doses of ZTO microspheres could prolong the average survival time considerably. None of the severe signs such as the pimelosis, fibrotic changes and fibrous septum were detected in the histopathology study.

In this work, we developed a novel active targeting and pH-responsive system for delivering the drug doxorubicin (DOX) to tumor sites using folic acid (FA)-modified multiwalled carbon nanotubes (MWCNTs). Acid-treated MWCNTs with carboxyl groups were first covalently conjugated with polyethyleneimine (PEI). Subsequent sequential modification with FA (via a polyethylene glycol spacer), fluorescein isothiocyanate (FI), and acetic anhydride/triethylamine resulted in multifunctional FA-bound MWCNT (MWCNT-PEI.Ac-FI-PEG-FA) nanomaterials that possessed exceptional colloidal stability and good biocompatibility in a given concentration range. The FA-bound MWCNTs were characterized using various techniques and exhibited a high drug loading and an encapsulation efficiency as high as 70.4%. DOX/MWCNT-PEI.Ac-FI-PEG-FA nanocomplexes (DOX/MWCNT NCs) exhibited pH-responsive release in acidic environments. Importantly, the DOX/MWCNT NCs targeted tumor cells overexpressing FA receptors (FARs) and effectively inhibited their growth. In vivo anticancer experiments demonstrated that DOX/MWCNT NCs not only enhanced the suppression of tumor growth but also decreased the side effects of free DOX. The developed FA-modified MWCNTs with an unconventionally high DOX loading boosted in vivo anti-tumor efficacy, and the lower systemic toxicity may be utilized for tumor therapy upon clinical translation.

The effect of the presence of HCl on cyclic CO2 capture behavior of calcium-based sorbent in the calcium looping process was investigated. When HCl was present in the carbonation atmosphere, the effects of carbonation temperature, calcination temperature, HCl concentration and particle size on CO2 capture of the limestone in the multiple calcination/carbonation cycles were studied in a dual fixed-bed reactor. The presence of HCl in the carbonation atmosphere improves CO2 capture capacity of the limestone in the previous a dozen cycles, but sharply decreases its reactivity with further increasing the cycle number above a dozen. The presence of HCl intensifies the effects of carbonation temperature and calcination temperature on CO2 capture capacity of the limestone. The optimum carbonation temperature and the feasible calcination temperature for cyclic CO2 capture of the limestone in the presence of HCl should be 700 °C and below 900 °C, respectively. The cyclic CO2 capture capacity of the limestone in the previous a dozen cycles achieves the maximum in the presence of 300 ppm HCl with increasing the HCl concentration from 100 to 1000 ppm. The higher CO2 capture capacity of the limestone is achieved with smaller particle size in the presence of HCl. The presence of HCl may destroy the compact CaCO3 product layer and it is beneficial to CO2 diffusion through the layer in the initial cycles. The chlorination conversion and the molten CaCl2–CaCO3 product layer thickness of the limestone in the presence of HCl increase with the number of calcination/carbonation cycles. It severely aggravates the sintering of the limestone once the cycle number is above about a dozen, which can be proved by microstructure analysis of the limestone experienced the multiple cycles in the presence of HCl.

The adsorption/desorption cycles of the alkaline paper mill waste (APMW) can be used to remove CO 2 from coal-fired power plants. In this work, the prolonged adsorption duration treatment was used to modify CO 2 capture behavior of the raw and the prewashed APMW in the multiple adsorption/desorption cycles. The effects of increased duration of adsorption and CO 2 partial pressure in the first cycle on the fractional adsorption of CO 2 and adsorption rate were investigated, when the raw and the prewashed APMW are employed as the sorbents. The cyclic CO 2 capture behavior of APMW after the repeated prolonged adsorption in different cycles was also studied. For the raw and the prewashed APMW as the sorbents, 9–12 h adsorption of CO 2 just in the 1st cycle enhances the cyclic fractional adsorption of CO 2 and adsorption rate of CO 2 in the 1st cycle and the subsequent cycles. The repeated prolonged adsorptions in the various cycles are more effective to increase the cyclic CO 2 capture capacity of APMW than only in the 1st cycle. The longer adsorption duration results in larger area and volume of pores in 10–100 nm in diameter for CaO derived from APMW after the next cycles, which are helpful to cyclic CO 2 capture of APMW. The raw and the prewashed APMW can retain high CO 2 adsorption reactivity by the prolonged adsorption duration treatment in the multiple adsorption/desorption cycles.

Carbide slag is a kind of industrial waste obtained in the production of acetylene that is the raw material of polyvinyl chloride in chlor-alkali plants. The carbide slag modified by pyroligneous acid was proposed as a CO2 sorbent at high temperature. The CO2 capture capacity of the carbide slag modified by pyroligneous acid in the calcium looping cycles was investigated in a thermogravimetric analyzer and a dual fixed-bed reactor. The modified carbide slag exhibits better CO2 capture capacity than the carbide slag. The modified carbide slag releases the organic substances whose combustion leads to a drop in CO2 capture capacity. The pre-calcination treatment of the modified carbide slag at 400 °C before the first calcination was employed to avoid the combustion of the organic substances. The pre-calcined modified carbide slag exhibits higher carbonation conversions, compared with the modified carbide slag without pre-calcination treatment. The pre-calcined modified carbide slag achieves higher carbonation conversions at 950 °C and shows larger surface area and pore volume than the modified carbide slag in the cycles. It indicates that combining the modification by pyroligneous acid with the pre-calcination treatment apparently improves cyclic CO2 capture capacity of the carbide slag in the multiple cycles. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.

The limestone modified by pyroligneous acid has been proved to have good CO2 capture behavior in the calcium looping process. In this work, SO2 retention of the highly cycled modified limestone in the carbonation/calcination cycles was investigated in a thermogravimetric analyzer (TG). The cyclic carbonation/calcination of the modified limestone was performed in a dual fixed-bed reactor and then the cycled modified limestone was sent for sulfation in TG. The effects of sulfation temperature, cycle number, and prolonged carbonation on SO2 retention of the cycled modified limestone were discussed. The optimum temperature for sulfation of the cycled modified limestone should be in the range of 900–950 °C. The effect of sulfation temperature on SO2 retention of the modified limestone drops with increasing cycle number. With increasing cycle number from 20 to 100, the sulfation conversion of the cycled modified limestone is stable and can reach ~0.4. The cycled modified limestone exhibits obviously higher SO2 retention than the cycled raw one for the same number of cycles. The prolonged carbonation increases SO2 retention of the modified limestone and the raw one after the subsequent cycles. The sulfation conversions of the modified limestone and the raw one at 118 min after 9-h carbonation in the 20th cycle increase 43 and 56 %, respectively. The cycled modified limestone shows a greater SO2 retention than the cycled raw one after the same prolonged carbonation treatment. The prolonged carbonation increases the pores in 5–20 nm range which is considered the optimum pore size for sulfation of CaO-based sorbent, so it results in an improvement in SO2 retention of the cycled sorbents.

Lime enhanced gasification (LEGS) process based on calcium looping in which CaO is employed as CO2 sorbent is an emerging technology for hydrogen production and CO2 capture. In this work, carbide slag which was an industrial solid waste was utilized as CO2 sorbent in hydrogen production process. Modification of carbide slag by propionic acid was proposed to improve its reactivity. The CO2 capture behavior of raw and modified carbide slags was investigated in a dual fixed-bed reactor (DFR) and a thermo-gravimetric analyzer (TGA). The results show that modification of carbide slag by propionic acid enhances its CO2 capture capacity in the multiple calcination/carbonation cycles. The favorable carbonation temperature and calcination temperature for modified carbide slag are 680–700 °C and 850–950 °C, respectively. Prolonged carbonation treatment is beneficial to CO2 capture of raw and modified carbide slags. The prolonged carbonation for 9 h in the 21st cycle increases the conversions of raw and modified carbide slags in this cycle. And then the carbonation conversions of the two sorbents were also improved in the subsequent cycles. Calcined modified carbide slag shows more porous microstructure compared with calcined raw one for the same number of cycles. Modification of carbide slag by propionic acid increases the surface area, pore volume and pore area. In addition, the volume and area of the pores in 20–100 nm in diameter were improved, which had been proved to be more effective to capture CO2. The microstructure of calcined modified carbide slag favors its higher CO2 capture capacity in the multiple calcination/carbonation cycles.

Lime mud (LM), a solid waste that results from the causticization reaction in alkali recycling process of paper manufacture industry, was utilized as CO 2 sorbent in calcium looping process in this study. The carbonation behavior of LM in the calcination/carbonation cycles was investigated in a dual fixed-bed reactor and a thermo-gravimetric analyzer. The results show that the carbonation conversions of LM are lower than those of limestone at the same reaction conditions. It attributes to the high chlorine content in LM which leads to more pronounced sintering and decreases the CO 2 capture performance of LM. A pre-wash process was employed to decrease the chlorine content in LM. Based on an overall consideration of various factors, the pre-wash process is effective enough if the Cl/Ca molar ratio in LM is smaller than 1:100. Pre-washed lime mud (PLM) achieves higher carbonation rates and carbonation conversions, compared with LM. When calcined at 850 °C and carbonated at 700 °C, the carbonation conversion of PLM maintains at 36% after 100 cycles, which is 1.8 and 4.8 times as high as LM and limestone after the same number of cycles, respectively. The pore volume and surface area of calcined PLM were greater than those of calcined LM after the same number of cycles, especially the volume of the pores in the range of 10–100 nm in diameter. That is the reason why PLM exhibits higher CO 2 capture capacity than LM in the multiple calcination/carbonation cycles. The carbonation conversions of LM and PLM are further enhanced by hydration of their calcines.

In order to understand how the modification of limestone by propionic acid affects the CO 2 capture performance, limestone was modified with propionic acid in this study. A thermo-gravimetric analyzer and a dual fixed-bed reactor were employed to investigate the CO 2 capture capacity of the modified limestone during cyclic calcination/carbonation reactions. The microstructure of the calcined modified limestone was examined by SEM and nitrogen physisorption tests. The results show that the modified limestone achieves faster carbonation rates and higher carbonation conversions than the untreated one during cyclic reactions. The carbonation conversion of the modified limestone is 0.31 after 100 cycles, 3.9 times as the carbonation conversion of the untreated one. The surface areas of the calcined modified limestone are higher than that of the calcined untreated one after the same cycles. For the calcined modified limestone, the pores distributed in 2–20 nm are more abundant than the untreated one, which contribute plenty of surface area for carbonation reactions. Therefore, the modified limestone can achieve higher carbonation conversions than the untreated one during cyclic reactions.

The CO2 capture behavior of carbide slag as industrial waste dumped from a chlor-alkali plant in calcination/carbonation cycles was investigated in a fixed-bed reactor and a thermogravimetric analyzer, which was furthermore compared with that of hydration of CaO (Hy-CaO) and limestone. The main component of the carbide slag was the same as that of Hy-CaO which was Ca(OH)2. The effects of reaction temperature, particle size and cycle number on CO2 capture of the carbide slag were discussed. The carbide slag exhibited greater ultimate carbonation conversion than Hy-CaO and the limestone for the same number of cycles. For the same number of cycles, the calcined carbide slag had a smaller volume of pores 155 nm in diameter than the two other calcined sorbents. This was maybe a reason why the carbide slag exhibits a higher ultimate carbonation conversion than the Hy-CaO and the limestone. The cyclic carbonation conversion of the carbide slag was lower than that of the limestone before a certain time (called transition time); however, the converse result was observed after that time. It was attributed to the difference in the volume of pores

In this work, SO2 capture behavior of CaO derived from the dolomite and the limestone during long-term carbonation/calcination cycles for CO2 capture at fluidized bed combustion (FBC) temperatures was investigated. The cyclic carbonation/calcination of CaO was performed in a dual fixed-bed reactor and then the cycled CaO was sent for sulfation in a thermo-gravimetric analyzer. At the typical FBC temperatures (850–950 °C), SO2 capture capacity of CaO from the different carbonation/calcination cycles increases with the increasing the temperature. The sulfation conversion of CaO derived from the dolomite (CaO-dolomite) decreases as the carbonation/calcination cycle number increases from 0 to 200. Although the sulfation conversion of CaO derived from the limestone (CaO-limestone) decreases with increasing the cycle number from 0 to 40, its conversion does not always decay with the number of cycles. The sulfation conversion of CaO-limestone shows a slight increase with increasing the cycle number from 40 to 150 and then exhibits a decrease with increasing the cycle number further. The sulfation conversions of CaO-limestone after different cycles are determined by the specific surface area and the volume of macropores >0.2 μm in diameter. The particle size and SO2 concentration have important effect on sulfation behavior of CaO from various cycles.

The effects of manganese salts including Mn(NO 3 ) 2 and MnCO 3 on CO 2 capture performance of calcium-based sorbent during cyclic calcination/carbonation reactions were investigated. Mn(NO 3 ) 2 and MnCO 3 were added by wet impregnation method. The cyclic CO 2 capture capacities of Mn(NO 3 ) 2 -doped CaCO 3 , MnCO 3 -doped CaCO 3 and original CaCO 3 were studied in a twin fixed-bed reactor and a thermo-gravimetric analyzer (TGA), respectively. The results show that the addition of manganese salts improves the cyclic carbonation conversions of CaCO 3 except the previous cycles. When the Mn/Ca molar ratios are 1/100 for Mn(NO 3 ) 2 -doped CaCO 3 and 1.5/100 for MnCO 3 -doped CaCO 3 , the highest carbonation conversions are achieved respectively. The carbonation temperature of 700–720 °C is beneficial to CO 2 capture of Mn-doped CaCO 3 . The residual carbonation conversions of Mn(NO 3 ) 2 -doped and MnCO 3 -doped CaCO 3 are 0.27 and 0.24 respectively after 100 cycles, compared with the conversion of 0.16 for original one after the same number of cycles. Compared with calcined original CaCO 3 , better pore structure is kept for calcined Mn-doped CaCO 3 during calcium looping cycle. The pore volume of calcined MnCO 3 -doped CaCO 3 is 2.4 times as high as that of calcined original CaCO 3 after 20 cycles. The pores of calcined MnCO 3 -doped CaCO 3 in the pore size range of 27–142 nm are more abundant relative to clacined original one. That is why modification by manganese salts can improve cyclic CO 2 capture capacity of CaCO 3 .

In this work, CaO derived from the carbide slag (CaO–carbide slag) as a kind of typical industrial waste was used to capture CO2 during the calcination/carbonation cycles. The carbonation kinetics and cyclic carbonation behavior of CaO–carbide slag were investigated in a thermogravimetric analyzer. The chemical reaction activation energy and the product layer diffusion activation energy for carbonation of CaO–carbide slag are 12.46 and 36.83 kJ mol−1, respectively, which are significantly less than those for carbonation of CaO derived from the limestone (CaO–limestone). CaO–carbide slag shows higher carbonation conversion than CaO–limestone after enough reaction time and at the same number of cycles. Moreover, the calcination temperature and CO2 concentration in the carbonation atmosphere have important effect on the carbonation behavior of CaO–carbide slag. The BET surface area of CaO–carbide slag is 1.6 times as large as that of CaO–limestone after 1 cycle and the average pore size of CaO–carbide slag is much smaller. In addition, the carbide slag contains much more Al2O3 than most of the limestones. These are reasons why carbide slag as a precursor can retain greater carbonation conversion than limestone in calcination/carbonation cycles.

In this work, pyroligneous acid (PA) was used to modify limestone, and the CO2 capture capacity in calcination/carbonation cycles was consequently strengthened. The cyclic CO2 capture behavior of PA-modified limestone was investigated in a thermogravimetric analyzer and a dual fixed-bed reactor. The main component of the PA-modified limestone was found to be calcium acetate hydrate. The optimum ratio of PA to limestone was found to be 20 mL/g. The PA-modified limestone was found to retain a higher CO2 capture capacity for carbonation at 700 °C. The carbonation conversion of the PA-modified limestone achieved 0.33 after 103 cycles, whereas, for the original sorbent, the conversion was just 0.078 under the same reaction conditions. The modification of limestone increased the surface area and pore volume of the calcined material during cycles. Furthermore, the calcined form of the modified limestone had more pores in the ranges of 1.8–4.6 and 18–155 nm, and as a result, its surface area and pore volume were ...

The calcination characteristics, sulfation conversion, and sulfation kinetics of a white mud from paper manufacture at fluidized bed combustion temperatures were investigated in a thermogravimetric analyzer. Also, the comparison between the white mud and the limestone in sulfation behavior and microstructure was made. Although the white mud and the limestone both contain lots of CaCO3, they are different in the alkali metal ions content and microstructure. It results in a marked difference in sulfation behavior between the white mud and the limestone. The CaO derived from white mud achieves the maximum sulfation conversion of 83% at about 940 °C which is 1.7 times higher than that derived from limestone at about 880 °C. The shrinking unreacted core model is appropriate to analyze the sulfation kinetics of the white mud. The chemical reaction activation energy E a and the activation energy for product layer diffusion E p for the sulfation of the white mud are 44.94 and 55.61 kJ mol−1, respectively. E p for the limestone is 2.8 times greater than that for the white mud. The calcined white mud possesses higher surface area than the calcined limestone. Moreover, the calcined white mud has more abundant pores in 4–24 nm range which is almost optimum pore size for sulfation. It indicates that the microstructure of the white mud is beneficial for SO2 removal.

Thermal decomposition characteristic of calcium magnesium acetate (CMA), calcium acetate (CA) and magnesium acetate (MA) are investigated through thermogravimetric (TG) analysis at the heating rates of 5 K min−1, 7.5 K min−1, 10 K min−1 and 15 K min−1. After dehydration, the evaporation of carboxylic radical and carbon dioxide of CMA and CA exist in two separate segments, but for MA, this occurs together in just one segment without clear borderline. The curves of calculated CMA (C-CMA) and the deduced characteristic parameters illustrate the different characteristic of CA and MA from the corresponding components in CMA which may be the reason for the different performances of these sorbents in SO2 and NOx reduction. Also, the kinetic parameters of activation energy and reaction order of the three sorbents are calculated through Vyazovkin method and Avrami theory, respectively.

The carbide slag from polyvinyl chloride production as industry hazardous wastes was proposed as CO2 sorbent at high temperature in calcium looping cycle. The cyclic CO2 capture behavior and the microstructure characteristics of the carbide slag as one of the typical calcium-based industrial wastes during the multiple calcination/carbonation cycles. Also, the comparisons between the carbide slag and the natural limestone in cyclic CO2 capture behavior were made. XRD analysis demonstrates that the predominating constituent of the carbide slag is Ca(OH)2. The carbonation temperature ranging from 650 to 700°C is favourable to cyclic carbonation of the carbide slag. The cyclic carbonation conversions of the carbide slag is lower than that of the limestone before a certain time, but the situation is converse after that time in a thermogravimetric analyzer. The carbide slag has better cyclic CO2 capture capacity. The carbonation conversion of the carbide slag retains 0.28 after 100 calcination/carbonation cycles, while the two limestones achieve 0.08 and 0.14 respectively at the same reaction conditions in a dual fixed-bed reactor. The microstructure of the carbide slag by SEM reveals the reason why it possesses better CO2 capture capacity.