BULELENG – Coal is the raw material used by PLTU (Steam Power Plant) to produce electricity. PT General Energy Bali (GEB) or better known as PLTU Celukan Bawang has its own way and system so that the supply of coal from suppliers is guaranteed to meet the needs of electricity production.
This was stated by Helmy Rosadi, PLN Dispatch Coordinator of PT GEB. “GEB prepares coal in accordance with the declaration of readiness for availability which is planned every month. We have a coal supply target every month which has been informed to the supplier. So now, towards the end of the month, we are asking suppliers of how many tons of coal can be sent to GEB, depending on the contract of each supplier. So even though later the realization of the burden requested by PLN (Capacity Factor / CF%) is less than the declaration of readiness, it can be our reserve. So far, the realized load factor has always exceeded the declaration plan because the GEB PLTU is the only mainstay of PLN to be optimized on the island of Bali, besides being cheap but reliable," he told VOI who contacted him on Friday, February 18.
Currently, said Helmy, the supply of coal at GEB is always in sufficient condition. “GEB's coal stock is always above 15 HOP (Operation Days). In the last few weeks, it has even reached above 20 HOP in accordance with PLN's target for each generator to be more than 15 HOP for supply security in the future. For information, the daily demand for coal if it is charged with full load 24 hours / day is around 5,000 t/h 3 units, "he explained.
Now GEB is collaborating with well-known coal suppliers. There are three main suppliers that meet GEB's needs; KPC, Adaro and SLBM. These three suppliers import coal from the island of Kalimantan. So far, the supply from the three suppliers, Helmy said, has been smooth. However, there have been several times the delivery was delayed due to weather factors, but it can still be resolved.
In order to ensure the smooth supply of coal, there is a special contract between GEB and the supplier. “For the GEB coal contract with PLN, the 'Pass Through' system is used. Meanwhile, GEB buys coal according to needs from suppliers at own cost. Then we bill it to PLN in the form of component C at the beginning of every month, "said Helmy.
Coal Quality
Coal supplied to GEB must have certain quality standards. And this is stated in the employment contract between the supplier and GEB. “The coal specifications sent to us must be in accordance with the coal contract with PLN, namely the CSA (Coal Supply Agreement) which has stated a certain range of calories, moisture, ash content, AFT, slagging index in accordance with the specifications of the GEB boiler. And this specification has been recorded in the contract with each coal supplier for GEB. So the supplier already knows this specification which is contained in the COA (Coal of Analysis) and published by the supplier before the coal is sent to our PLTU, "said Helmy.
The quality standard of the coal used must be in accordance with the agreed specifications, because the quality of the coal greatly affects the operation of the unit, especially in the boiler. So that the electricity production produced by the PLTU is in accordance with the CF requested by PLN and the declared AFp target.
Then where does the waste from burning coal go and can it be used for other purposes? According to Helmy, in the future there is a possibility that this waste will be used but for now we are sending it to the island of Java via a certified transporter. “There are two types of PLTU coal waste, namely fly ash and bottom ash. The fly ash waste is transported using a closed capsule truck to be directly transported by a third party LB3 transporter to the island of Java. Meanwhile, bottom ash waste is carried by dump trucks from the bottom ash bin to the ash yard temporary shelter at the PLTU. Then the LB3 transporter also brought it," he said.
For now, Helmy continued, no use of this coal waste has been made or used for other useful materials. However, in the future there is a discourse that PLN Bali Distribution will cooperate with GEB for the utilization of this waste which will be used as a cement mixture. This is due to the request of several traditional banjars around the island of Bali to improve local road access. Currently being discussed how the scheme will be utilized. It will inform further if an agreement has been reached.
So far, said Helmy GEB using the latest technology in combustion. “GEB PLTU is designed to use steam turbine reheat, which is a technology that is quite expensive. Where the turbine steam is fed back to the boiler pipe (reheat) to be reheated, so it can be efficient and especially can save the supply of raw water (demineralized water). The GEB turbine is designed with an installed capacity of 3x142 MW," he explained.
When asked whether the obstacles faced so far, Helmy emphasized that it was not without problems, but that all of them could be overcome. “Operational constraints can be categorized in two ways, namely internal and external. So far, there are not too many internal problems due to the contract of the Celukan Bawang PLTU with the O&M (Operational & Maintenance) company, one of which is maintaining the operational reliability of the unit so that the monthly AF (Availability Factor) is achieved. O&M has several operating and maintenance strategies to ensure the reliability of its machines," he said.
According to Helmy, one of the external constraints is related to the quality of incoming coal. "Regarding external constraints, such as the quality of coal that does not match the specifications, it will greatly affect engine performance, especially combustion in the boiler, which can cause massive slagging, which can cause some equipment to be disrupted, as a result, our unit has to take the load off for a while to deal with it," said Helmy. Rosadi.
The English, Chinese, Japanese, Arabic, and French versions are automatically generated by the AI. So there may still be inaccuracies in translating, please always see Indonesian as our main language. (system supported by DigitalSiber.id)
