FEASIBILITY STUDY OF BINARY SYSTEM AS A BOTTOMING UNIT PLTP DIENG-1

• Main Author: Gracia Ade Sumartha, Ayu
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43997
• Institution: Institut Teknologi Bandung

Dieng-1 geothermal power plant (PLTP) with a single flashed type of plant has been operating since 2002 with total generating capacity of 60 MW. Since operating in 2002, there has been a decline in production capacity from the plant due to problems at production wells, production facilities, and injection wells. To increase production of the power plant, optimization of the system is carried out. Optimization conducted by utilizing the energy contained in the brine separator output to produce electricity. The type of plant that can be used to utilize brine from a separator is a binary system. The utilization of brine by using a binary system as a bottoming unit for the Dieng-1 PLTP is included in the business plan of PT. Geo Dipa Energi (Persero) so that the study of the binary system as a bottoming unit for the Dieng-1 PLTP is interesting to do. The main problem when utilizing geothermal brine is the formation of scaling due to the complex chemical composition of the brine so a comprehensive study of this development plan is necessary. The purpose of this study is to produce optimal operating conditions in terms of technical and economic aspects. The binary type used in this study is organic rankine cycle (ORC) with recuperator. The use of brine for binary systems is limited by the conditions of the scaling formation at the generating facility. The working fluids used in this study are n-pentane, iso-pentane, and n-butane. Calculation of the thermodynamic properties of the working fluid is calculated using REFPROP and a binary system simulation process is carried out using ASPEN Hysys 8.8. The result of this research shows that the use of iso-pentane working fluids gives the best results from technical and economic aspects. The gross power produced is 11570 kW and net power is 10160 kW with the thermal efficiency of the system is 15.3%. The development cost for this system is 2418.5 USD/kWh. This field development will be conducted by investors with a brine sale and purchase scheme. Brine selling price of 0.011-0.021 USD/kWh for IRR of 10-16% and NPV value of 0.01-4.73 Million USD with electricity prices of 74 USD / kWh in the Dieng geothermal field.