Metoda dekomposisi batubara berdasarkan neraca elemen dan teori devolatilisasi dari data analisa proksimat dan ultimat
DOI:
https://doi.org/10.5614/jtki.2007.6.1.3Abstract
The coal gasification theoretical performance is usually estimated using a thermodynamic model. This model should produce idealistic performances of a gasifier. However, the thermodynamic approach reqitires a known chemical formula of the coal. Coal is known as a hydrocarbon solid fuel. Its chemical formula is very complex and unknown. The solution for this problem is solved by decomposing the coal into known chemical substances. The present decomposing method of the coal is developed by complying to mass balance of the coal using both ultimate and proximate analysis's. The coal is composed into light gases, tars and char. The components of these substances are determined from the established devolatization theory. The light gases are considered as a mixture of Hp, C01, HCN, CH4, H2S, CO, and H2. Tars can be represented by C16H10, C10H14O2, C9H7N, and C4H4S. The char remains carbon only (C). The ash is still as ash. This present method is more realistic method than a conventional one. The calculated gasification performances using decomposed coal from this method are also considered to be more realistic. With this method, effect of coal types on their gasification performances can be investigated.
Keywords: Coal, Decomposition, Devolatilisation, Gasification
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Abstrak
Kajian kinerja gasifikasi batubara pada kondisi kesetimbangan kimia memerlukan infomasi rumus molekul bahan yang terlibat. Rumus molekul batubara sendiri belum didifinisikan secara pasti. Masalah ini diatasi dengan cara pendekomposian batubara ke komponen kimia yang diketahui rumus molekulnya. Makalah ini menyampaikan hasil penelitian dalam hal pengembangan metoda dekomposisi yang didasari oleh neraca unsur dengan menggunakan data analisa proksimat dan ultima!. Disamping ini, teori devolatilisasi digunakan dalam memperkirakan jenis bahan teruap yang dihasilkan oleh peristiwa dekomposisi batubara. Batubara terdekomposisi menjadi gas-gas ringan, tar-tar dan arang. Komponen dan fraksi massanya dipekirakan mengikuti kaidah neraca massa dan teori devolatilisasi. Gas-gas ringan yang dimaksud adalah gas-gas Hp, C01, HCN, CH4, H2S, CO, and H2. Tar yang dilibatkan dalam bentuk senyawa C16H10, C10H14O2, C9H7N, and C4H4S. Arang tetap diwakili oleh karbon (C) dan abu tetap dalam bentuk abu. Metoda dekomposisi yang dikembangkan sekarang adalah metoda yang realistik berlandaskan teori devolatilisasi. Metoda ini disebut metoda dekomposisi realistik. Perkiraan kinerja gasifikasi untuk batubara yang didekomposisi dengan metoda realistik memberikan hasil yang lebih realistik dimana gas-gas ringan dan tar dapat tercakup sebagai komponen-komponen yang terurai dari hasil devolatilisasi. Metoda inijuga membuka kajian-kajian lebih mendalam untuk gasifikasi batubara dengan melibatkan tipe batubara itu sendiri.
Kata Kunci: Batubara, Dekomposisi, Devolatilisasi, Gasifikasi
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