Objectives :
- To assess energy alternative for industrial boiler
- To assess the combustion characteristic of CWM
- To develop feeding system of CWM by using boiler simulator and laser dopler velocimeter
- Oil crisis in 1970’s accelerates humankind to find alternative for oil resources. An abundance of coal resources has positioned its role as the most popular fuel alternative for oil substitute by direct combustion or by coal conversion into oil or gaseous fuel.
- One of direct coal utilization is by mixing coal and water before burning to make slurry that behaves like liquid fuel.
- The idea for making coal water mixture is based on assumption that liquid fuel is easier to be handled in distribution and transportation and also the advantage of difficulties in self- ignition or self-explosion.
- By coal water mixture, transportation system dan coal distribution from mining location to the port or the user can be accomplished using piping system without unnecessarily constructing an expensive infrastructure in solid fuel.
- Coal water mixture can be utilized as oil substitute in an existing boiler industries. The advantage of boiler using liquid of coal water mixture over solid coal is cheaper capital cost more compact in operation and easier in fuel handling.
- Realizing the Indonesian coal resources reaching 3.6 billion tonnes and the advantages of coal water mixture over the solid coal, UPT-LSDE shows its competency to assess and to do research in application of the coal water mixture as a fuel in industrial boiler.
- Characteristic of coal water mixture is more complex than its coal because other than the phisico-chemical characteristic of its original coal, the behavior of coal mixture with water has to be understood through the science of rheology.
- Some of the important characteristic of coal water mixture includes stability, fluidity and combustion characteristics.
- Burning coal water mixture in a furnace is achieved by spraying or atomizing, hence coal concentration particle size and viscosity is three dominant factors in its combustion. Therefore, characterizing of coal water mixture is necessary before its burning in industrial boiler.
The activities of Chemical and Combustion Group of UPT-LSDE includes :
- Testing of stability and fluidity of coal water mixture
- Designing of atomizer dan burner system
- Characterizing of coal water mixture combustion
- For good storage and transportation, coal water mixture shall have good stability difficulties in settling) and an easiness of flowing (fluidity).
- The making of coal water mixture is using a dispersant additive to disperse the coal as much as possible in the as little as possible of water.
- An experience shows that coal concentration in coal water mixture is around 50–60 % weight for various additives.
- Some additives that has been used in the making of coal water mixture in UPT-LSDE are CMC, KOAL, CAO, Coal Master etc.
- Atomizing coal water mixture before combustion process plays an important role by realizing that the success of its combustion very much depends on the success of coal water mixture atomization.
- This good atomization can be achieved by designing a reliable burner system and atomizer.
- UPT-LSDE has designed and developed burner system and atomizer.
- The purpose of design is to achieve a suitable burner system and atomizer type for CWM atomization with good atomization ability and can be rely on for application in the commercial scale of boiler industries.
- For combustion, good CWM shall have high coal concentration because an existence of water will increase heat losses for water evaporation. However, high coal concentration will increase viscosity of CWM and in turn will create difficulties in handling and atomizing CWM.
- Testing of CWM combustion is achieved in Boiler Furnace Simulator (usually to combust pulverized solid coal) by modifying its burner system and atomizer.
- The testing is achieved to get the data of reliability burner system and combustion characteristic of CWM i.e., combustion efficiency, velocity and length of flame.
- Such data shall be useful in CWM application in an industrial boiler.
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