Catalytic properties of a composite material based on belarusian dolomites in relation to the decomposition of pyrolysis tar

The paper discusses results of an experimental study of the thermal decomposition of pyrolysis tar in a homogeneous process and in the presence of a catalyst. Experiments on thermal decomposition of pyrolysis tar were carried out under isothermal conditions in a laboratory setup at temperatures of 300, 400, 450 and 500 °C. The rate of the homogeneous process of thermal decomposition of tar and maximal degrees of decomposition were determined. According to the data of this work, the activation energy of the homogeneous process was 320 kJ/mol. It was found that the rate of thermal decomposition of the tar increases in the case of introducing samples of natural dolomites into the reaction zone, as well as a composite material based on them. This increase is due to the occurrence of a heterogeneous catalytic decomposition reaction of the pyrolysis tar. The apparent activation energy of this process was 210 kJ/mol (when using dolomites) and 202 kJ/mol (when using composites). It was noted that the composite material has significantly more favorable mechanical properties than dolomite. Based on the established data, it was concluded that the creation of composite catalysts for the thermal decomposition of heavy hydrocarbons formed in the processes of thermochemical conversion of biomass is promising.

Potensi Produksi Asap Cair, Arang dan Tar dari Limbah Industri Pengolahan Kayu

The practice of burning and stockpiling to reduce wood waste from the wood processing industry is not in line with the demands of clean production, environmentally friendly and sustainable industries. Pyrolysis technology can be used to produce bioenergy from wood waste. The temperature and the time of the pyrolysis process, the water content of materials, and the content of different yields between types of wood waste affect the bioenergy products produced. This study was aimed at determining the effect of wood waste form and condition on the quality and quantity of liquid smoke, tar, and charcoal. A Completely Randomized Design with two factors of treatments, i.e., waste forms and the drying process, was applied in this research. The results showed that the condition and shape of the material affect the volume of liquid smoke and the weight of the charcoal produced. The condition of the material without drying with high water content and the shape of the chunks produce more liquid smoke with an average yield of 191.14 mL and 186.37 mL, while the charcoal produced is higher in the condition of the material with drying and shaved form at 125.83 g and 115.62 g. The results of the test characteristics of grade 1 and 2 distillation liquid smoke meet the Japanese liquid smoke quality standards with phenol levels in the range of 26.66-35.94 mg GAE/mL sample and acidity levels of 16.91-58.9%. Keywords: Char; liquid smoke; pyrolysis; tar; wood waste. ABSTRAK Praktik pembakaran dan penimbunan untuk mereduksi limbah kayu dari industri pengolahan kayu tidak selaras dengan tuntutan produksi bersih, ramah lingkungan dan industri berkelanjutan. Teknologi pirolisis dapat digunakan untuk memproduksi bioenergi dari limbah kayu dengan suhu dan waktu proses pirolisis, kadar air bahan serta kandungan rendemen yang berbeda antar jenis limbah kayu mempengaruhi produk bioenergi yang dihasilkan. Penelitian ini bertujuan untuk mengetahui pengaruh bentuk dan kondisi limbah kayu terhadap kualitas dan kuantitas asap cair, ter dan arang. Metode penelitian yang dilakukan adalah Rancangan Acak Lengkap yang disusun secara faktorial dengan perlakuan bentuk limbah dan proses pengeringan. Hasil penelitian menunjukan bahwa kondisi dan bentuk bahan mempengaruhi volume asap cair dan bobot arang yang dihasilkan. Kondisi bahan tanpa pengeringan dengan kadar air tinggi dan bentuk bongkah menghasilkan asap cair lebih banyak dengan hasil rata-rata 191,14 mL dan 186,37 mL, sedangkan arang yang dihasilkan lebih tinggi pada kondisi bahan dengan pengeringan dan bentuk serut yaitu 125,83 g dan 115,62 g. Hasil uji karakteristik asap cair distilasi grade 1 dan 2 memenuhi standar mutu asap cair Jepang dengan kadar fenol berada pada kisaran 26,66-35,94 mg GAE/mL sampel dan kadar keasaman 16,91-58,9 %. Kata kunci: Arang; asap cair; limbah kayu; pirolisis; ter.

The Homogeneous Conversion Mechanism of Cellulose Pyrolysis Tar Under the Effect of Steam

Biomass accounts for the largest proportion of rural solid waste with high moisture content, which affects the thermal treatment process. This paper studied the effect of steam on the pyrolysis tar of microcrystalline cellulose (MCC) by a two-stage fixed bed. The experiments had been carried out under different steam/feedstock mass ratios (S/F= 0, 0.8, 1.2, 1.6) when the first stage was at 600℃, and the second stage was at 800 ℃. The tar content in the syngas was reduced effectively from 6.68% to 2.30% when the S/F was from 0 to 1.6. Under the four S/F conditions, aromatic compounds accounted for more than 80%, which was the largest proportion of tar products. Significantly, formic acid phenyl ester (FAPE) decreased obviously with the growth of S/F. Besides, when the steam content was excessive, the MAHs, such as phenols and indenes, could be further cyclized and aromatized to form PAHs. To further study the removal mechanism of tar, the FAPE was investigated by density functional theory (DFT). It was concluded that the O3-C4 bond of FAPE was most likely to be attacked by the H2O molecule to form phenol, CO2, and H2 directly, among the four possible paths.

Effect of Steam on the Homogeneous Conversion of Tar Contained from the Co-Pyrolysis of Biomass and Plastics

The co-pyrolysis tar formed from microcrystalline cellulose (MCC) and polyethylene (PE) was used to study their further conversion path under the effect of steam. This paper addressed the yield and transformation of tar with different steam/feedstock mass ratios (S/F= 0.8, 1.6) in a two-stage fixed-bed when the two stages furnace temperature was set at 600℃ and 800℃, separately. Compared with pyrolysis, steam promoted tar cracking effectively, the tar yield decreased at least 1/3. However, with the addition of steam, the cracking effect of tar is not further improved. The tar yield depended more on the PE content in the mixture, which was enhanced with PE increment. Besides, the H/C atom ratio was related to the conversion path of tar. Steam was beneficial to the cracking of compounds, but the generated hydrogen radicals affected the direction of the subsequent reaction. The steam mainly promotes the cracking of long-chain hydrocarbons, accompanied by cyclization and aromatization when the steam was limited. Nevertheless, these reactions were hindered when the steam was excessive due to the apparent effect of hydrogenation. In this process, the short-chain hydrocarbons come to recombine instead of cyclization and aromatization.

The Homogeneous Conversion Mechanism of Cellulose Pyrolysis Tar Under the Effect of Steam

Biomass accounts for the largest proportion of rural solid waste with high moisture content, which affects the thermal treatment process. This paper studied the effect of steam on the pyrolysis tar of microcrystalline cellulose (MCC) by a two-stage fixed bed. The experiments had been carried out under different steam/feedstock mass ratios (S/F= 0, 0.8, 1.2, 1.6) when the first stage was at 600℃, and the second stage was at 800 ℃. The tar content in the syngas was reduced effectively from 6.68% to 2.30% when the S/F addition was from 0 to 1.6. The steam could promote craking of compounds to form more stable compounds. To further study the removal mechanism of tar, the main tar component, phosphonic acid, (p-hydroxyphenyl-) , was investigated using density functional theory (DFT). It was concluded that intermediate product from cellulose pyrolysis was more likely to react with H 2 O and made against the production of phosphonic acid, (p-hydroxyphenyl-), consistent with the experimental results.

Porous silicon film overcoating biomass char-supported catalysts for improved activity and stability in biomass pyrolysis tar decomposition

In this work, porous silicon film overcoating biomass char-supported catalysts were synthesized and evaluated biomass pyrolysis tar decomposition reactions. With the presence of Ni and Fe (SC@Ni1Fe1@SiO2), high-density and well-dispersed...