Penghasilan syngas (hidrogen, H2 dan karbon monoksida, CO) melalui
karbon dioksida pembaharuan metana (CRM) merupakan satu proses yang
berpotensi. Reaksi ini menggunakan dua gas rumah hijau, iaitu, metana, CH4 dan
karbon dioksida, CO2. Biogas merupakan bahan mentah yang murah dan sesuai
untuk proses CRM kerana mengandungi CH4 dan CO2 yang bernisbah 1:1. Walau
bagaimanapun, pemangkin yang diperbuat daripada unsur-unsur bumi dan aktif
dalam CRM masih dalam permintaan justeru dijadikan objektif penyiasatan dalam
projek ini. Dalam kajian ini, aktiviti Co(x)Al(3-x)O4 dan Co-Al2O3-CoAl2O4 telah
disiasat. Jumlah kandungan kobalt, Co dalam pemangkin telah diubah dan
ditandakan sebagai x%-Co, di mana x adalah diantara 11.11% dan 42.83%. Co(x)Al(3-
x)O4 telah disintesis dengan kaedah sol-gel dengan berbagai kandungan Co dan Al
manakala Co-Al2O3-CoAl2O4 telah disediakan dengan tindak balas x%-Co yang baru
disintesis dengan H2. 33.33%-Co merupakan pemangkin terbaik yang menghasilkan
90.37 % dan 96.02 % hasil untuk H2 dan CO pada 900 °C, halaju berat ruang per jam
(WHSV) 15000 mlg-1h-1 dengan kandungan CH4:CO2 bernisbah 1:1. Tiada
berlakunya pereputan aktiviti pemangkin dalam tempoh 24 h dan kadar pemendapan
karbon adalah pada 3.1×10-2 g·gcat-1·h-1. 33.33%-Co yang telah bertindak balas
dengan H2 pula dapat menghasilkan penukaran CH4 dan CO2 sebanyak 72.89 % dan
79.49 % pada 750 °C dengan kadar pembentukan karbon sebanyak 1.7×10-2 g·gcat-
1h-1. Kajian terhadap kesan kandungan Co dalam x%-Co yang telah bertindak balas
dengan H2 dalam reaksi CRM mendedahkan bahawa 15.79%-Co dapat mencapai
penukaran CH4 dan CO2 sebanyak 67.39 % dan 78.54 % pada 750 °C, WHSV 30000
mlg-1h-1 dengan kandungan CH4:CO2 bernisbah 1: 1 selama 50 h dengan kadar
pemendapan karbon pada 4.26×10-4 g·gcat-1·h-1.
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The production of syngas (hydrogen, H2 and carbon monoxide, CO) through
carbon dioxide reforming of methane (CRM) is a promising process that
simultaneously utilizes two greenhouse gases, i.e., methane, CH4 and carbon dioxide,
CO2. Currently, the use of biogas as a cheap feedstock for CRM is very alluring due
to the its nearly 1:1 ratio of CH4 and CO2 content, which is ideal for this reaction.
However, a catalyst made of earth-abundant elements and highly active in CRM is
still in demand thus was made a subject of investigation in this project. In this study,
the activity of Co(x)Al(3-x)O4 and Co-Al2O3-CoAl2O4 catalysts were investigated. The
amount of cobalt, Co content in the catalyst were altered and denoted as x%-Co,
where x range from 11.11% to 42.83%. Co(x)Al(3-x)O4 were prepared by sol-gel
method at different Co and Al loading while Co-Al2O3-CoAl2O4 were prepared by
reducing the freshly synthesized x%-Co compound with H2. 33.33%-Co was the best
performing catalyst which produced 90.37% and 96.02% yield for H2 and CO,
respectively at 900 °C, weight hourly space velocity (WHSV) of 15000 mlg-1h-1 and
CH4 to CO2 feed ratio of 1:1. There was no observable catalytic activity decay within
24 h of reaction time and the rate of carbon deposition was at 3.1×10-2 g·gcat -1
·h-1. Reduced 33.33%-Co was able to produces CH4 and CO2 conversion of 72.89 % and
79.49 %, respectively at 750 °C with a carbon formation rate of 1.7×10-2 g·gcat
-1h-1. Study on the effect of Co content on reduced x%-Co in CRM reaction revealed that
15.79%-Co was able to achieve a constant conversion of 67.39 % and 78.54 % for
CH4 and CO2, respectively at the reaction temperature of 750 °C, WHSV of 30000
mlg-1h-1 and CH4 to CO2 feed ratio of 1:1 for 50 h with rate of carbon deposition at
4.26×10-4 g·gcat -1·h-1.
Synthesis and characterization of CoAl2O4 and Co-Al2O3-CoAl2O4 catalysts activity in carbon dioxide reforming of methane_Wong Yee Jie _K4_2016_MYMY