Rasio Kontrol Laju Aliran Udara dan Bahan Bakar untuk Optimalisasi Pembakaran pada Vertical Fire Tube Boiler

Segar, Yus Putri Arum (2026) Rasio Kontrol Laju Aliran Udara dan Bahan Bakar untuk Optimalisasi Pembakaran pada Vertical Fire Tube Boiler. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pengendalian laju aliran udara dan bahan bakar merupakan faktor penting dalam menjaga efisiensi pembakaran pada boiler berbahan bakar Liquefied Petroleum Gas (LPG). Rasio udara terhadap bahan bakar (Air-Fuel Ratio atau AFR) yang tidak sesuai dapat menyebabkan pembakaran tidak sempurna, meningkatkan konsumsi bahan bakar, menurunkan efisiensi termal, serta meningkatkan emisi gas buang seperti CO dan NOx. Pada Vertical Fire Tube Boiler berbahan bakar LPG, proses pembakaran berlangsung lebih cepat dibandingkan boiler berbahan bakar padat sehingga memerlukan pengendalian udara yang lebih presisi untuk menjaga kestabilan nyala api. Penelitian ini bertujuan merancang sistem kontrol rasio laju aliran udara dan bahan bakar berbasis PLC Mitsubishi FX3U-14MT dan sensor Mass Flow Meter MF5712 untuk mengoptimalkan proses pembakaran LPG. Sistem mengatur laju aliran udara menggunakan blower DC yang dikendalikan dengan metode Pulse Width Modulation (PWM). Pengujian dilakukan pada dua kondisi operasi, yaitu sebelum dan sesudah penerapan sistem kontrol rasio, dengan boiler digunakan untuk memanaskan air bermassa 15 kg selama air telah menyentuh 100°C. Pada kondisi awal, laju aliran bahan bakar LPG ditetapkan sebesar 5 L/menit, sedangkan setelah penerapan sistem kontrol rasio diturunkan menjadi 4 L/menit sesuai rasio udara–bahan bakar yang telah ditentukan. Efisiensi boiler dihitung menggunakan metode langsung (direct method) dengan membandingkan energi panas yang diserap air terhadap energi panas hasil pembakaran bahan bakar. Hasil perhitungan menunjukkan bahwa energi keluaran boiler pada kedua kondisi pengujian tetap sebesar 4.959 kJ, sedangkan energi masukan menurun dari 23.506 kJ menjadi 18.814 kJ akibat berkurangnya konsumsi LPG. Penurunan energi masukan tersebut meningkatkan efisiensi boiler dari 21,11% menjadi 26,36%, atau meningkat sebesar 5,25 poin persentase. Hasil penelitian menunjukkan bahwa penerapan sistem kontrol rasio udara–bahan bakar mampu meningkatkan efisiensi termal boiler melalui pengurangan konsumsi bahan bakar tanpa mengurangi energi panas yang diserap air, sehingga proses pembakaran menjadi lebih efektif.
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Air and fuel flow rate control is a critical factor in maintaining combustion efficiency in boilers fuelled by Liquefied Petroleum Gas (LPG). An improper Air–Fuel Ratio (AFR) may result in incomplete combustion, increased fuel consumption, reduced thermal efficiency, and higher emissions of exhaust gases such as CO and NOx. In LPG-fired Vertical Fire Tube Boilers, the combustion process occurs more rapidly than in solid-fuel boilers, requiring more precise air flow control to maintain flame stability. This study aims to design an air–fuel ratio control system based on a Mitsubishi FX3U-14MT Programmable Logic Controller (PLC) and an MF5712 Mass Flow Meter sensor to improve the combustion efficiency of an LPG-fired boiler. The system regulates the air flow rate using a DC blower controlled by the Pulse Width Modulation (PWM) method. Experiments were conducted under two operating conditions, namely before and after the implementation of the air–fuel ratio control system, with the boiler used to heat 15 kg of water until the water temperature reached 100°C. Under the initial operating condition, the LPG flow rate was set to 5 L/min, while after implementing the ratio control system it was reduced to 4 L/min in accordance with the predetermined air–fuel ratio. Boiler efficiency was evaluated using the direct method by comparing the heat energy absorbed by the water with the heat energy released from fuel combustion. The results show that the boiler output energy remained constant at 4,959 kJ under both operating conditions, whereas the input energy decreased from 23,506 kJ to 18,814 kJ due to the reduction in LPG consumption. Consequently, the boiler efficiency increased from 21.11% to 26.36%, representing an improvement of 5.25 percentage points. These findings demonstrate that the implementation of the air–fuel ratio control system enhances the thermal efficiency of the boiler by reducing fuel consumption without decreasing the heat energy absorbed by the water, thereby improving the overall combustion process.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Vertical Fire Tube Boiler, Pembakaran LPG, Laju Aliran Udara, Rasio Kontrol, Vertical Fire Tube Boiler, LPG Combustion, Air Flow Rate, Ratio Kontrol
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ223.P76 Programmable controllers T Technology > TJ Mechanical engineering and machinery > TJ263.5 Boilers (general) T Technology > TJ Mechanical engineering and machinery > TJ223 PID controllers
Divisions:	Faculty of Vocational > Instrumentation Engineering
Depositing User:	Yus Putri Arum Segar
Date Deposited:	30 Jul 2026 04:41
Last Modified:	30 Jul 2026 04:41
URI:	http://repository.its.ac.id/id/eprint/139536

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