Efisiensi Penambahan Bahan Bakar Sekam Padi Di Rotary Kiln Pada Pabrik Semen Portland

Industri semen merupakan salah satu industri yang berkembang sangat pesat seiring dengan pertumbuhan pembangunan di Indonesia. Semen merupakan komoditas strategis sebagai penunjang perekonomian nasional melalui program pembangunan infrastruktur, gedung, perumahan, dan fasilitas umum lainnya. Kondisi ini mempengaruhi meningkatkan permintaaan kapasitas produksi yang dihasilkan industri semen. Penambahan kapasitas produsksi berdampak terhadap pada ketersediaan bahan baku semen diantaranya batu kapur (limestone), tanah liat (clay), pasir besi (iron sand), dan pasir silika (silika sand). Dalam hal ini, Wonogiri memiliki sumber ketersediaan batu kapir yang tinggi terutama pada daerah Baturetno. Kapasitas produksi pabrik Semen Portland yang akan didirikan yaitu 2.200.000 ton/tahun akan beroperasi secara continous selama 300 hari/tahun. Proses pembuatan semen yang dipilih adalah proses kering. Proses kering meliputi proses persiapan bahan batu kapur dan tanah liat di crusher lalu dipecah oleh hammer dan melewati clay cutter sehingga terjadi size reduction. Produk raw mil dialirkan ke preheater, lalu diumpan ke proses pembakaran di kiln sehingga menghasilkan senyawa clincer yang kemudian didinginkan didalam clincer cooler. Proses pengiilingan akhir diumpan kedalam ball mill dengan bahan tambahan gypsum dan fly ash menjadi semen yang berukuran 325 mesh. Optimasi dilakukan dengan cara subtitusi bahan bakar biomassa pada bahan bakar batubara pada proses pembakaran di kiln yang menunjukkan bahwa bahan bakar biomasa sekam padi dibandingkan dengan penggunaan batubara 100% dapat menurunkan emisi CO2 sebesar 1,8721 ton CO2-eq dan menurunkan dampak pemanasan global sebesar 0,2147 ton CO2-eq. Analisa ekonomi diperoleh total biaya bahan baku pertahun sebesar Rp69.335.891 dengan harga semen Rp30.000 per/50 kg. Selain itu diperoleh nilai Internal Rate of Return (IRR) sebesar 35% per tahun dengan Pay Out of Time (POT) I sebesar 1,9 tahun dan Break Even Point (BEP) sebesar 41%. Nilai Present Value sebesar Rp276.405.521.129 ====================================================================================================================================== The cement industry is one of the industries that is growing very rapidly along with the growth of development in Indonesia. Cement is a strategic commodity to support the national economy through infrastructure, buildings, housing and other public facilities development programs. This condition affects the increasing demand for production capacity produced by the cement industry. The addition of production capacity has an impact on the availability of cement raw materials including limestone (limestone), clay (clay), iron sand (iron sand), and silica sand (silica sand). In this case, Wonogiri has a source of high availability of limestone, especially in the Baturetno area. The production capacity of the Portland Cement plant to be established is 2,200,000 tons/year and will operate continuously for 300 days/year. The selected cement manufacturing process is a dry process. The dry process includes the process of preparing limestone and clay in the crusher and then breaking it down by hammer and passing through the clay cutter so that size reduction occurs. The raw mil product is flowed into the preheater, then fed to the combustion process in the kiln to produce clincer compounds which are then cooled in the clincer cooler. The final milling process is fed to a ball mill with additional materials of gypsum and fly ash into cement with a size of 325 mesh. Optimization is done by substitution of biomass fuel on coal fuel in the combustion process in the kiln which shows that rice husk biomass fuel compared to the use of 100% coal can reduce CO2 emissions by 1.8721 tons CO2-eq and reduce the impact of global warming by 0 ,2147 tons CO2-eq. Economic analysis obtained the total cost of raw materials per year is Rp. 69,335,891 with a cement price of Rp. 30,000 per/50 kg. In addition, the Internal Rate of Return (IRR) value is 35% per year with a Pay Out of Time (POT) I of 1.9 years and a Break Even Point (BEP) of 41%. Present Value of Rp. 276,405,521,12