Tailoring the Stabilization and Pyrolysis Processes of Carbon Molecular Sieve Membrane Derived from Polyacrylonitrile for Ethylene/Ethane Separation

For ethylene/ethane separation, a CMS (carbon molecular sieve) membrane was developed with a PAN (polyacrylonitrile) polymer precursor on an alumina support. To provide an excellent thermal property to PAN precursor prior to the pyrolysis, the stabilization as a pre-treatment process was carried out. Tuning the stabilization condition was very important to successfully preparing the CMS membrane derived from the PAN precursor. The stabilization and pyrolysis processes for the PAN precursor were finely tuned, and optimized in terms of stabilization temperature and time, as well as pyrolysis temperature, heating rate, and soaking time. The PAN stabilized at >250 °C showed improved thermal stability and carbon yield. The CMS membrane derived from stabilized PAN showed reasonable separation performance for ethylene permeance (0.71 GPU) and ethylene/ethane selectivity (7.62), respectively. Increasing the pyrolysis temperature and soaking time gave rise to an increase in the gas permeance, and a reduction in the membrane selectivity. This trend was opposite to that for the CMS membranes derived from other polymer precursors. The optimized separation performance (ethylene permeance of 2.97 GPU and ethylene/ethane selectivity of 7.25) could be achieved at the pyrolysis temperature of 650 °C with a soaking time of 1 h. The separation performance of the CMS membrane derived from the PAN precursor was comparable to that of other polymer precursors, and surpassed them regarding the upper bound trade off.

Surface morphology properties of biochar feedstock for soil amendment

A soil amendment is any material added to a soil to improve soil physical properties, support plant growth, improve soil fertility, organic matter, and water holding capacity, improve soil chemical and biological properties. Biochar is an organic amendment that improve soil fertility, mitigates climate change, and effectively keeps nutrients and available to plants. The chemical and physical properties of the biochar are important to know the suitable applications of biochar. The chemical and physical properties of the biochar are depending on the process and biomass feedstock. The research aimed to find out the kind of biomass feedstock for biochar as a soil amendment. The biochar feedstock was evaluated using scanning electron microscopy (SEM) and electron dispersive X-ray (EDX) analysis and can predicting possible uses for the biochars. The result showed that the biochar surface morphology properties were influenced by the feedstock types and pyrolysis temperature. The pores development and mineral contents in coconut shell biochar are the most suitable for soil amendment.

Optimasi Kadar Ultimate dan Tingkat Kebasaan Bio-arang Limbah Kayu Durian sebagai Pembenah Tanah

Konversi biomassa melalui pirolisis menghasilkan bio-arang, bio-minyak dan gas. Pirolisis biomassa dipengaruhi oleh kondisi pirolisis seperti bahan baku dan suhu pirolisis. Tujuan dari penelitian ini adalah menganalisis kondisi optimum kadar ultimate (CHO) dan pH bio-arang berdasarkan ukuran partikel bahan baku limbah kayu durian dan suhu pirolisis sebagai pembenah tanah. Limbah kayu durian yang digunakan dalam penelitian ini berukuran diameter 0,17–0,42 mm; 0,42–1,00 mm; dan 1,00–2,83 mm, dengan variasi suhu pirolisis 350°C, 450°C, dan 550°C sebanyak tiga kali ulangan. Optimasi menggunakan metode Response Surface Methodology. Berdasarkan model kuadratik, didapatkan kadar karbon optimum bio-arang sebesar 81,78% dengan ukuran partikel bahan baku pada 2,09 mm dan suhu pirolisis 530,5oC. Kadar hidrogen optimum bio-arang sebesar 3,35% dengan ukuran partikel bahan baku 2,89 mm dan suhu pirolisis 547,4oC. Kadar oksigen optimum bio-arang sebesar 12,22% dengan ukuran partikel bahan baku 1,89 mm dan suhu pirolisis 529,5oC. pH optimum bio-arang sebesar 8,35 dengan ukuran partikel bahan baku 0,6 mm dan suhu pirolisis 521,8oC. Kondisi proses terbaik untuk menghasilkan kadar ultimate dan pH yang paling optimal berada pada range ukuran diameter bahan baku 0,6 mm–2,89 mm dan suhu pirolisis sebesar 521,8oC–547,4oC. The Optimization of Ultimate Levels and Basicity of Durian Wood Waste Biochar as Soil AmendmentAbstractBiomass conversion through pyrolysis produces biochar, bio-oil and gas. Pyrolysis of biomass is influenced by pyrolysis conditions such as raw materials and pyrolysis temperature. The purpose of this study was to analyze the optimum conditions for ultimate levels (CHO) and pH of biochar based on the particle size of the durian wood waste and the pyrolysis temperature as soil amendment. Particle sizes of durian waste were 0.17–0.42 mm; 0.42–1.00 mm; and 1.00–2.83 mm in diameter where pyrolysis temperatures were 350°C; 450°C; and 550°C. Optimization was used by the Response Surface Methodology method. Based on the quadratic model, the optimum carbon content of biochar was 81.78% with the particle size at 2.09 mm and the pyrolysis temperature of 530.5oC. The optimum hydrogen content of biochar was 3.35% with a particle size of 2.89 mm and a pyrolysis temperature of 547.4oC. The optimum oxygen content of biochar was 12.22% with a particle size of 1.89 mm and a pyrolysis temperature of 529.5oC. The optimum pH of biochar was 8.35 with a particle size of 0.6 mm and a pyrolysis temperature of 521.8oC. The most optimal ultimate levels and pH were in the diameter size range of 0.6 mm-2.89 mm and pyrolysis temperature of 521.8oC-547.4oC.

Thermogravimetric Analysis and Kinetic Calculation on the Combustion Characteristics of Two Typical Shenhua Chars

Recently, a new ultra-low nitrogen combustion technology, pyrolysis and gasification coupling combustion, was proposed. The dependence on SCR or SNCR was reduced measurably with this technology. However, given the lower content of volatile matter in semi-chars, the burn-up ratio and combustion efficiency seemed to become lower. Thus, in this study, the combustion characteristics of the Shenhun and Carboniferous char were investigated under combustion conditions with the thermogravimetric method; meantime, kinetic calculation on the combustion characteristics were evaluated with Coats–Redfern method. Experiments indicated that Shenhun char showed good ignition and burnout characteristics when the pyrolysis temperature ranged from 973.15 K to1073.15 K; meanwhile, Carboniferous char showed good ignition and burnout characteristics when the pyrolysis temperature ranged from 873.15 K to 973.15 K. Besides, both the calculations and experiments indicated that Shenhun char showed better combustion characteristics than Carboniferous char.