Crude Furnace Floor Creep Assessment and Remaining Life Assessment due to Hot Spots

Fitness for Service (FFS) assessment and remaining life assessment of the furnace floor plates in a crude charge heater where hot spots up to 500°C have been observed during operation in 2018 was undertaken as a pre assessment prior to the unit turnaround. The remaining life assessment results would provide the turnaround team with firm scope for repair in order to resintate the bottom plate and avoid discovery scope. Two Finite Element (FE) models were created to account for hotspot temperature conditions measured at November 2018 and June 2019. Each of these FE models involved successive loading conditions, so that the effects of each loading scenario could be investigated. The loading conditions were applied in steps, in the following order: 1. Gravity. 2. Temperature, modelling hotspot behaviour. 3. Creep, viscoelastic analysis. Utilising the FE models created for the two hotspot conditions, remaining life was calculated and suggested that the worst location for creep damage is near burner 2 (the maximum creep damage location of the November 2018 condition). Based on the assessment, the following recommendations are made: 1. Continue to observe and maintain temperatures below the creep temperature range (i.e. no additional hotspots are created and temperatures are not increasing). 2. Undertake creep testing from metal samples. 3. Re-inspect in 8 years at the same locations where metallographic replication was performed in September 2019.

Modification and Test Performance of Rack Type Hybrid (Solar-Biomass) Dryer

This study aimed to modify biomass furnaces source of heat energy from the combustion of biomass, study thermal energy generated from combination of solar and biomass energy, and determine efficiency of furnaces and efficiency of total system of a rack type hybrid (solar-biomass) dryer. Method used in this research was experimental method. Used fuel was coconut shell charcoal and used tools include iron plate, blower, pipe, grinding and welding tools, thermometer, anemometer, lux meter, data logger and analytical balance. Observed parameters were temperature, air humidity, sun radiation, velocity and flow rate of hot air towards the drying chamber, drying period, energy loss and energy produced inside the furnace. Modification made by adding drawer shaped biomass furnace with 0.65 m length, 0.65 m wide and 0.25 m height. The furnace was equipped with a chimney and blower. Results from the test performance showed that this tool yield total heat loss of 18,173.15 KJ at the upright furnace wall. Whereas heat loss at furnace floor was 4380.899 KJ. Energy consumption was 151,602.064 for solar energy and 48,399.4 KJ for biomass energy, with total drying energy generated by solar energy and biomass i.e. 200,001 KJ. Efficiency value of the drying system was 19% with 30% furnace efficiency. Keywords: Hybrid dryer, heat loss, biomass furnaces ABSTRAK Penelitian ini bertujuan untuk memodifikasi tungku biomassa sebagai tempat sumber energi panas dari pembakaran biomassa, mempelajari energi panas yang dihasilkan oleh kombinasi energi surya dan energi biomassa, dan mengetahui efisiensi tungku dan efisiensi total sistem pada alat pengering hybrid (surya-biomassa) tipe rak. Metode yang digunakan dalam penelitian ini yaitu metode eksperimental. Bahan bakar yang digunakan yaitu arang tempurung kelapa dan alat yang digunakan antara lain plat besi, blower, pipa, gerinda, las, thermometer, anemometer, lux meter, data logger, dan timbangan analitik. Parameter yang diamati terdiri dari suhu, kelembaban udara, radiasi matahari, kecepatan aliran udara panas menuju ruang pengering, debit aliran udara menuju ruang pengering, lama waktu pengeringan, kehilangan energi pada tungku dan energi yang dihasilkan. Modifikasi yang dilakukan adalah menambahkan tungku biomassa yang berbentuk seperti laci dengan ukuran panjang 0,65 m, lebar 0,65 m dan tinggi 0,25 m. Tungku ini dilengkapi dengan cerobong asap dan blower. Hasil pengujian alat ini diperoleh total kehilangan panas pada dinding tegak tungku 18.173,15 KJ, sedangkan kehilangan panas pada lantai tungku 4.380,899 KJ. Konsumsi penggunaan energi, yaitu energi surya 151.602,064 KJ dan energi biomassa 48.399,4 KJ dengan total energi pengeringan yang dihasilkan oleh energi surya dan biomassa sebesar 200.001 KJ. Nilai efisiensi sistem pengeringan yang dihasilkan yaitu 19% dengan efisiensi tungku 30%. Kata kunci: alat pengering Hybrid, kehilangan panas, tungku biomassa

The Resolution of a Dryout Induced On-Load Corrosion Problem in the Sloping Furnace Tubes of an Operational Boiler

SYNOPSIS Failures due to on-load corrosion have occurred in the steam generating tubes forming the sloping furnace floor of a large, high pressure boiler. Measurements carried out on the operating plant have shown the cause to be tube wall dryout. The data obtained have enabled plant operating conditions to be detailed which avoid dryout. Close agreement has been shown between the plant data and the results obtained from comprehensive rig tests.