Climatic conditions in Indonesia warm up indicated by the increasing of the average annual temperature by 0.3°C. This may cause higher water evaporation and increased rainfall intensity. Changes in rainfall patterns shift the start of the rainy season to be slower and end faster. These changes the dry season to become longer with shorter time intervals. In case of dam operation, dam manager needs to adapt the effects of climate change. This paper presents trend and future projection in Riam Kanan Catchment Area, Banjar Regency, South Kalimantan. Climate change historical trend analysis was carried out with the observation data used were rainfall and maximum temperature from BMKG climatology station, Banjarbaru Station, in the period 1983 - 2017. Future projection analysis was carried out by using RCP2.6 and RCP8.5 scenario data for projecting rainfall and temperature in the period 2018 - 2100. The result shows that the rainfall, maximum temperature, and evapotranspiration trends in Banjarbaru from 1983 - 2017 were not too significant by +0.1 mm, -0.5°C, and +0.1 mm. While the projection of RCP2.6 and RCP8.5 scenario shows increase by +0.1 mm, +0.1°C, +0.1 mm and by +0.1 mm, +3.3°C, and +0.1 mm. Keywords: Climate Change, Trend, Rainfall, Temperature, Evapotranspiration, RCP 2.6, RCP8.5.
The material of the tubes has suffered localized overheating and corrosion, probably as a result of local heat flux impingement phenomenon, combined with high temperature corrosion. Boiler tubes that experienced failure indications were tubes material SA 213 T22 with the dominant alloy elements is Cr. Materials with these specifications are which should be resistant to corrosion, so it is necessary to carry out laboratory testing to answer suspected indications of failure. The methodology of analysis and identification carried out is by observing the microstructure in 3 dimensions supported by other mechanical tests, namely visual observation, hardness testing, chemical composition testing using SEM and EDAX and testing the chemical composition of the material using a spectrum analyzer. Observation using an optical microscope shows that the microstructure condition of the tube is ferritic and the results of 3D metallography observations show that the tube has undergone micro crack with a measured depth of 1853,28 μm. After the metallography testing is carried out, the hardness test is carried out with the hardness vickers (HV) unit and the minimum hardness is 149 HV and the maximum hardness is 177 HV. Testing of the chemical composition of the deposit showed that there were chemical elements found in seawater that trigger corrosion such as sodium and chlorine which enter the water vapor system. The results showed that the tube had pitting corrosion, which was indicated by the presence of microcrack at the grain boundaries and an oxide deposit had been formed which would cause an overheating phenomenon and deterioration.
In a coal steam power plant, changes in coal quality significantly affect plant performance, especially in its boiler. A coal-fired power plant with a capacity of 400 MWe had been commissioned using coal with a calorific value of 5,242 kCal/kg. This study aims to determine the effect on unit performance and boiler efficiency due to changes in fuel use with the typical calorific value of 3,520 kCal/kg, 34,17% lower than the initial design. The performance tests were conducted using the heat loss method at loads: 50%, 65%, 75%, and 100%. The test result showed that using low-grade coal reduces boiler efficiency by 6.26%. There were four dominant boiler losses: heat loss due to moisture in dry flue gas, heat loss due to combustible in refuse, heat loss due to moisture in fuel, and heat loss due to hydrogen burning. Furthermore, the gross plant heat rate using low-grade coal was increased from 2,120 kCal/kWh to 2,718 kCal/kWh; however, the electric price becomes cheaper from 1.99 cent-USD/kWh becomes 1.31 cent-USD/kWh.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.