Permittivity‐Based Microwave Absorption Characteristics of Dongsheng Lignite during Pyrolysis

Wang, Guanghua; Chen, Biao; Wang, Shijie

doi:10.1002/ente.201500437

Cited by 6 publications

(4 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dielectric properties of materials determine the feasibility and economic benefits of microwave heating, , and their ability to attenuate microwave energy, which can be represented by complex relative permittivity, penetration depth, and average power density of dielectric loss, ,,− as shown in eqs , , and , and , respectively. As indicated by eq , ε is the complex relative permittivity, which consists of ε′ and ε″. ε′ is the real part, which reflects the ability of the dielectric material to store electric field energy due to polarization.…”

Section: Results and Discussionmentioning

confidence: 99%

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

et al. 2020

View full text Add to dashboard Cite

Combined with the advantages of microwave pyrolysis and catalytic pyrolysis, the microwave pyrolysis experiment of low-rank coal under the synergism of catalyst was carried out. The dielectric response of coal samples and metal compound catalysts to microwave was analyzed quantitatively. The microwave pyrolysis behavior and product distribution of low-rank coal were studied. The effects of microwave heating and catalyst properties on the properties of pyrolysis products were analyzed in depth. Results show that the heating effect of dielectric loss and ionic conduction loss of metal compound catalysts could further promote the rapid temperature rise of coal samples. The catalysts could effectively improve the product distribution and properties in the process of microwave pyrolysis of low-rank coal. Compared with the control group, the output of syngas (H 2 + CO) increases by a maximum of 1.72 times, and the content of asphaltene in tar reduces by a maximum of 0.66 times. The introduction of K 2 CO 3 and CaCl 2 is conducive to the formation of a more developed pore structure and the increase of the specific surface area of semicoke. The co-action of the developed pore structure of semicoke and properties of residual catalysts could significantly improve the CO 2 gasification activity of semicoke.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The dielectric loss of metal catalyst were much higher than that of coal, which the ability of consume microwave energy was greater, resulting in their temperature-rising rates was higher during microwave irradiation, thus the metal catalyst formed the "hot spots" in coal [23,24]. In addition, when the pyrolysis temperature was below 800 ℃, the generation of char under high pyrolysis temperature was also conducive to improve the dielectric loss [25,26]. With the pyrolysis temperature increasing, the dielectric losses of catalyst and char sharply decreased and then kept stable, which led to maintain stability for the final pyrolysis temperature.…”

Section: Pyrolysis Temperaturementioning

confidence: 99%

Metal Sulfide Assisted Coal Catalytic Hydrogenated Microwave Pyrolysis

Liu

Yue

2020

MSF

View full text Add to dashboard Cite

The efficient cleaning conversion of coal is more and more attracted due to resource exhaustion and environmental pollution. To improve the yield and quality of products of coal pyrolysis, the catalytic hydrogenated microwave pyrolysis was introduced, and the effects of metal sulfide on hydrogenated microwave pyrolysis were focused on discuss via the detection methods of proximate and ultimate analyses, SEM-EDS, FT-IR and GC-MS in this work. The results shown that because of the “hot-spot” effect and the characteristics of electromagnetic loss of metal sulfide, the temperature-rising rates with catalysts were obviously higher, but the final pyrolysis temperatures with or without catalyst were almost close. Higher temperature-rising rate with catalysts made the yield of liquid product more, which the yields of liquid product with MoS2 and FeS2 catalyst were 28.4 wt.% and 27.1 wt.%. The carbon distributions indicated that carbon in solid and gaseous products transferred into liquid product, when the catalysts added into pyrolysis reactions. The quality of tar with catalyst was improved, and the component content of light oil, intermedium oil and heavy oil were 67.55 wt.%, 27.98 wt.% and 4.47 wt.% for MoS2 catalyst, in which the content of light oil increased by 10.30 times than that without catalyst. The thermal effect and catalysis of metal metal sulfide made complex aromatic compounds more thorough cracking, improved the amount and active of free hydrogen. Actived free hydrogen further enhanced cracking of heavy oil, resulting in the content of hydrogen in gaseous with catalysts decrease, and the content of light oil increased.

show abstract

“…Low‐rank coals (LRCs) reserve account for a large proportion of total coal resources in China, and are characterized by high content of volatiles, moisture and oxygen, but low heating value . Pyrolysis is an important technology for achieving clean and efficient utilization of LRCs .…”

Section: Introductionmentioning

confidence: 99%

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al₂O₃ Catalysts

Cao

Wang

et al. 2020

ChemistrySelect

View full text Add to dashboard Cite

In-situ upgrading of coal pyrolysis tar with steam catalytic cracking (SCC) is a promising technique to improve tar quality. In this study, Ni/Al 2 O 3 catalysts with different Ni contents were used for in-situ SCC of coal pyrolysis tar at 650°C. The results showed that Ni/Al 2 O 3 catalysts can enhance the water conversion and light tar yield. Both SCC and tar catalytic cracking can occur simultaneously over Ni/Al 2 O 3 , and the free radicals produced by tar catalytic cracking can be stabilized by active species generated from SCC to avoid excessive cracking of tar and improve light tar yield. 4Ni/Al 2 O 3 (4 wt. % Ni) exhibits the best performance, contributing to the highest water conversion of 4.74 wt. % and light tar yield of 11.90 wt. %, respectively.Correspondingly, the content of light fraction (boiling point less than 360°C) in tar sample increases from 48.0 wt. % to 67.0 wt. %, and the average molecular weight decreases from 353 amu to 253 amu over 4Ni/Al 2 O 3 . This is consistent with the increase of benzenes, phenols and naphthalenes and the decrease of long-chain aliphatic hydrocarbons, 3-and 4-ring aromatics in upgraded tar. In addition, the higher ratio of uncondensed aromatic protons to condensed aromatic protons in upgraded tar reveals the fact that 4Ni/Al 2 O 3 can promote ring-opening reaction of PAHs, which can well interpret the tar upgrading process.

show abstract

Permittivity‐Based Microwave Absorption Characteristics of Dongsheng Lignite during Pyrolysis

Cited by 6 publications

References 25 publications

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

Metal Sulfide Assisted Coal Catalytic Hydrogenated Microwave Pyrolysis

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al₂O₃ Catalysts

Contact Info

Product

Resources

About

Permittivity‐Based Microwave Absorption Characteristics of Dongsheng Lignite during Pyrolysis

Cited by 6 publications

References 25 publications

Microwave-Assisted Pyrolysis of Low-Rank Coal with K2CO3, CaCl2, and FeSO4 Catalysts

Microwave-Assisted Pyrolysis of Low-Rank Coal with K2CO3, CaCl2, and FeSO4 Catalysts

Metal Sulfide Assisted Coal Catalytic Hydrogenated Microwave Pyrolysis

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al2O3 Catalysts

Contact Info

Product

Resources

About

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al₂O₃ Catalysts