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Journal of Environmental Sciences 2024年第4期138卷 428-438页

作者： Jing Yang Yujie Ren Shuoyu Chen Jinsuo Lu School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

This study aimed to explore the chemical looping gasification(CLG)reaction characteristics of the metal-supported composite phosphogypsum(PG)oxygen carriers(OCs)and the thermodynamic mechanism.The FactSage 7.1 thermodynamic simulation was used to explore the oxygen release and H_(2)S removal mechanisms.The experimental results showed that the syngas yield of CLG with PG-CuFe_(2)O_(4)was more than that with PG-Fe_(2)O_(3)20/CuO40 or PG-Fe_(2)O_(3)30/CuO30 OC at 1023 K when the water vapor content was 0.3.Furthermore,the maximum syngas yield of the CO selectivity was 70.3% and of the CO_(2)selectivity was 23.8%.The H_(2)/CO value was 0.78,and the highest carbon conversion efficiency was 91.9% in PG-CuFe_(2)O_(4)at the gasification temperature of 1073 K.The metal-supported PG composite oxygen carrier was proved not only as an oxygen carrier to participate in the preparation of syngas but also as a catalyst to catalyze coal gasification reactions.Furthermore,both the experimental results and FactSage 7.1 thermodynamic analysis revealed that the trapping mechanism of H_(2)S by composite OCs was as follows:CuO first lost lattice oxygen as an oxygen carrier to generate Cu_(2)O,which,in turn,reacted with H_(2)S to generate Cu_(2)S.This study provided efficient guidance and reference for OC design in CLG.

关键词： Metal-supported composite phosphogypsum Reaction characteristics Thermodynamic mechanism chemical looping gasification

chemical looping gasification characteristics and kinetic analysis of Chlorella and its organic components

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Carbon Resources Conversion 2022年第3期5卷 211-221页

作者： Song Wu Bo Zhang Bolun Yang Jianxuan Shang Hongzhi Zhang Wei Guo Zhiqiang Wu Shaanxi Key Laboratory of Energy chemical Process Intensification School of Chemical Engineering and TechnologyXi’an Jiaotong UniversityXi’anShaanxi 710049PR China Shaanxi Coal and chemical Technology Institute Co. Ltd.ShaanxiXi’an710065PR China

chemical looping gasification(CLG)characteristics and kinetic analysis of Chlorella(CHL),simulated Chlorella(V-CHL)and medium-chain triglycerides(MCT)were investigated using a thermogravimetric analyzer coupled with an online mass spectrometer.The apparent activation energy was obtained via Kissinger-Akahira-Sunose(KAS)method.In the result of the weightless behavior,the addition of oxygen carrier inhibited the decomposition of V-CHL at lower temperatures but promoted its decomposition at high temperatures.The values of chemical looping process characteristic parameters showed that a 10 wt%oxygen carrier would maximize the release of volatile products in the CLG of MCT,with 5.12×10^(-6)%⋅min^(-1)⋅℃^(-3).Oxygen carriers also affected gaseous products.The LHV of gaseous products of CHL reached the largest when the oxygen carrier was 10 wt%,which was 8.13 MJ/m^(3).And the gaseous product of MCT had the largest LHV with 30 wt%oxygen carrier,which was 8.83 MJ/m^(3).According to the kinetic analysis,the minimum value of apparent activation energy of MCT chemical looping gasification was 89.54 kJ⋅mol^(-1) with the oxygen carrier of 30 wt%,which was 50%less than that of MCT pyrolysis.And the minimum value for V-CHL was obtained when the mass fraction of Fe2O3 was 50 wt%.This paper could provide a reference for the choice of algae,the design of reactors,and the targeted regulation of the gaseous product for the algae CLG process.

关键词： chemical looping gasification Algae Organic components Gaseous product distribution Kinetic analysis

Biomass chemical looping gasification for syngas production using modified hematite as oxygen carriers

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Journal of Environmental Sciences 2023年第3期125卷 171-184页

作者： Cong Jiang Xiaoyu Jin Tingting Xu Bo Xiao Zhiquan Hu Xun Wang School of Environmental Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Coal Combustion Huazhong University of Science and TechnologyWuhan 430074China

Syngas is a clean energy carrier and a major industrial feedstock. In this paper, syngas was produced via biomass chemical looping gasification(CLG) process. Hematite, the most common Fe-based oxygen carrier(OC), was modified with different metal oxides(CeO_(2), CaO and MgO) by the impregnation method. The hematite modified by CeO_(2), CaO and MgO was namely as CeO_(2)-hematite(CeO_(2)-H), CaO-hematite(CaO-H) and MgO-hematite(MgO-H), respectively. The introduction of CeO_(2), CaO and MgO enhanced the reactivity of lattice oxygen of hematite. The optimum condition for syngas production had been explored as the mass ratio of oxygen carrier to biomass(O/B) of 0.2, the mass ratio of steam to biomass(S/B) of0.75 and temperature of 800℃in the biomass CLG process. The CeO_(2)-H exhibited the most wonderful performance compared to that for CaO-H and MgO-H. The crystal composition of OC influenced greatly in the CLG process. CeFeO_(3)had a good oxygen mobility property and lattice oxygen releasing capacity due to the most oxygen vacancy distributed on the OC surface and the most active lattice oxygen, which is conducive to the biomass chemical looping gasification process for syngas production, leading to the highest gasification efficiency of 95.86% and gas yield of 1.20 m^(3)/kg of the three. Cyclic test proved that CeO_(2)-H had well sintering resistance and cyclic performance.

关键词： chemical looping gasification Oxygen carrier Syngas Modified hematite Pine sawdust

Retention mechanism of calcium ferrite and compositions of ash on selenium during chemical looping gasification

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Particuology 2023年第8期79卷 143-152页

作者： Ziheng Han Huifen Kang Nini Yuan Xintong Guo Jingjing Ma Qingjie Guo State Key Laboratory of High-efficiency Utilization of Coal and Green chemical Engineering College of Chemistry and Chemical EngineeringNingxia UniversityYinchuan750021China Key Laboratory of Clean chemical Engineering in Universities of Shandong College of Chemical EngineeringQingdao University of Science&TechnologyQingdao266042China

Selenium pollution by coal utilization is of increasing concern.Calcium-iron(Ca-Fe)oxygen carriers(OCs)and alkali metal ions have strong inhibitory effects on selenium,which can reduce the emissions of selenium vapor.The retention mechanisms of selenium by Fe_(2)O_(3),CaFe_(2)O_(4),Ca_(2)Fe_(2)O_(5) and bottom ash are investigated during chemical looping gasification(CLG).Iron-based OC can oxidize H_(2)Se(g)to SeO_(2)(g);furthermore,lattice oxygen is released by Fe_(2)O_(3),contributing to the formation of an Fe-O-Se structure to retain selenium and form selenite.Because calcium ferrite is poorly oxidizing,it cannot oxidize H_(2)Se(g),but the CaO produced when OCs are reduced can react with H_(2)Se(g)to form CaSe(s),and this process can be promoted by H_(2)S(g).The best retention rates reached 32.301%when Ca_(2)Fe_(2)O_(5) was used.In the cyclic experiment,the selenium retention of the bottom ash gradually increases.Alkali metal ions in bottom ash are the main factor in retaining selenium.Ca^(2+) and Mg^(2+) do not easily vaporize due to their high melting points;therefore,their selenium retention is significantly better than that of K^(+) and Na^(+).This research provided a new idea for the removal of selenium by using OCs and bottom ash par-ticles during CLG.

关键词： Selenium chemical looping gasification Oxygen carrier Retention mechanism Ashcomposition

Experimental and numerical simulation of lignite chemical looping gasification with phosphogypsum as oxygen carrier in a fluidized bed

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Chinese Journal of chemical Engineering 2021年第9期34卷 197-207页

作者： Wang Du Liping Ma Jing Yang Wei Zhang Ran Ao Faculty of Environmental Science and Engineering Kunming University of Science and TechnologyKunming 650500China School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an 710000China

Phosphogypsum(PG)is a solid waste produced in the wet process of producing phosphoric acid.Lignite is a kind of promising chemical raw material.However,the high sulfur of lignite limits the utilization of lignite as a resource.Based on fluidized bed experiments,the optimal reaction conditions for the production syngas by lignite chemical looping gasification(CLG)with PG as oxygen carrier were studied.The study found that the optimal reaction temperature should not exceed 1123 K;the mole ratio of water vapor to lignite should be about 0.2;the mole ratio of PG oxygen carrier to lignite should be about 0.6.Meanwhile,commercial software Comsol was used to establish a fuel reaction kinetics model.Through computational fluid dynamics(CFD)numerical simulation,the process of reaction in fluidized bed were well captured.The model was based on a two-fluid model and coupled mass transfer,heat transfer and chemical reactions.This study showed that the fluidized bed presents a flow structure in which gas and solid coexist.There was a high temperature zone in the middle and lower parts of the fluidized bed.It could be seen from the results of the flow field simulated that the fluidized bed was beneficial to the progress of the gasification reaction.

关键词： Phosphogypsum Lignite chemical looping gasification Fluidized-bed Syngas Computational fluid dynamics

chemical looping catalytic gasification of biomass over active LaNixFe1-xO_(3)perovskites as functional oxygen carriers

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Chinese Journal of chemical Engineering 2021年第8期34卷 146-156页

作者： Jingchun Yan Weidong Liu Rong Sun Shouxi Jiang Shen Wang Laihong Shen Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China College of Physics and New Energy Xuzhou University of TechnologyXuzhou 221018China

Oxygen carriers(OCs)with perovskite structure are attracting increasing interests due to their redox tunability by introducing various dopants in the structure.In this study,LaNixFe1-xO3(x=0,0.1,0.3,0.5,0.7,1.0)perovskite OCs have been prepared by a citric acid–nitrate sol–gel method,characterized by means of X-ray diffraction(XRD)analysis and tested for algae chemical looping gasification in a fixed bed reactor.The effects of perovskite types,OC/biomass mass ratio(O/B),gasification temperature and water injection rate on the gasification performance were investigated.Lower Ni-doped(0≤x≤0.5)perovskites crystalized in the rhombohedra system which was isostructural with LaNiO3,while those with composition 0.5≤x≤1 crystalized in the orthorhombic system.Despite the high reactivity for LaNiO_(3),LaNi_(0.5)Fe_(0.5)O_(3)(LN5F5)was found to be more stable at a high temperature and give almost as good results as LaNiO_(3)in the formation of syngas.The relatively higher syngas yield of 0.833 m^(3)·kg^(-1) biomass was obtained under the O/B of 0.4,water injection rate of 0.3 ml·min^(-1) and gasification temperature at 850C.Continuous high yield of syngas was achieved during the first 5 redox cycles,while a slight decrease in the reactivity for LN5F5 after 5 cycles was observed due to the adhesion of small grains occurring on the surface of OCs.However,an obvious improvement in the gasification performance was attained for LN5F5 compared to raw biomass direct gasification,indicating that LN5F5 is a promising functional OC for chemical looping catalytic gasification of biomass.

关键词： Biomass chemical looping gasification Oxygen carrier La-Ni-Fe perovskite Catalysis

A novel hybrid digestion-gasification process integrated with membranes for efficient conversion of biomass to bio-alcohols

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Green Energy & Environment 2021年第1期6卷 15-21页

作者： Xuezhong He Department of chemical Engineering Norwegian University of Science and TechnologyN-7491TrondheimNorway

There is an urgent need to develop technologies which enable the conversion of biomass into liquid biofuels to fill the gap between limited fossil fuel supplies and increasing worldwide demand.In order to achieve the EU 2030 vision of at least 15%of the fuels used in the road transportation sector will be biofuels derived from non-food biomass feedstocks,the R&D of clean,inexpensive,highly end-user compatible biofuels from a virtually inexhaustible source of biomass should be pursued to make breakthroughs in cost-effective biomass to liquid biofuels(BTL)technologies.Thus,an innovative,consolidated,and sustainable technology using a hybrid digestion-gasification process integrated with membranes to produce next generation bio-alcohols from different biomass feedstocks was designed.The proposed concept was theoretically estimated to achieve an overall BTL efficiency of 44%and a cost reduction for bioalcohol production of 18.6%.Moreover,this technology can potentially achieve an overall CO2 emission reduction of>75%for road transport based on the preliminary analysis.

关键词： Biofuels Biomass chemical looping gasification Membrane Anaerobic digestion

Simulation study on the gasification process of Ningdong coal with iron-based oxygen carrier

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Chinese Journal of chemical Engineering 2021年第1期34卷 326-334页

作者： Fei Xie Mei An Ping Li Xiude Hu Hongcun Bai Qingjie Guo State Key Laboratory of High-efficiency Utilization of Coal and Green chemical Engineering College of Chemistry and Chemical EngineeringNingxia UniversityYinchuan 750021China

chemical looping gasification(CLG) of Ningdong coal by using Fe_(2) O_(3) as the oxygen carriers(OCs) was studied,and the gasification characteristics were obtained.A computation fluid dynamics(CFD) model based on Eulerian--Lagrangian multiphase framework was established,and a numerical simulation the coal chemical looping gasification processes in fuel reactor(FR) was investigated.In addition,the heterogeneous reactions,homogeneous reactions and Fe_(2) O_(3) oxygen carriers' reduction reactions were considered in the gasification process.The characteristics of gas flow and gasification in the FR were analyzed and it was found that the experiment results were consistent with the simulation values.The results show that when the O/C mole rate was 0.5:1,the gasification temperature was 900℃ and the water vapor volume flow rate was 2.2 ml·min^(-1),the mole fraction of syngas reached a maximum value of the experimental result and simulation value were 71.5% and 70.2%,respectively.When the O/C mole rate was 0.5:1,the gasification temperature was 900℃,and the water vapor volume flow was 1.8 ml·min^(-1);the gasification efficiency reached the maximum value was 62.2%,and the maximum carbon conversion rate was 84.0%.

关键词： chemical looping gasification Fuel reactor gasification characteristics Fe_(2)O_(3)oxygen carrier