Pulverized coal injection method

Background

Iron is a most fundamental metal used for a life of human being, as it is rich in resource resulting in low price, can easily be extracted, and easily modified due to its useful material property. After an industrial revolution (18-19th century), iron becomes a core material of industrial market, its importance was referred to “iron is nation”, its productivity was directly treated as its national power. Therefore after the World War 2, government vigorously supported the growth of iron industrial market; as a consequence, the action significantly contributed and influenced the development of global economy. For the various application uses, iron ore is extracted and smelted through a uses of metallurgical furnace called “Blast Furnace”

Blast furnace is considered to survive for another century because of its highly efficient iron production rate at competitive costs with other iron making technology. Blast furnace efficiency keep on improving by adapting with new technological support which is stimulated from the accumulated global demand, yet the main chemical process remains same. Although improvement of process does not mean solving for the problem associated in uses of blast furnace. Iron production rate is highly influenced from world economics which varies over the time and improvement of operation efficiency can be considered as one of major concerns from uses of blast furnace, however biggest drawback of blast furnace operation is its inevitable carbon dioxide production from iron reduction processes, which is considered as major contributor in global warming. Nowadays, Pulverized Coal Injection (PCI) method is internationally popular method in improving blast furnace operation.

Pulverized Coal Injection method

Pulverized coal injection (PCI) method has been developed in 19th century however the method was not being implemented till the 1970s. Rise of concerns in increased coke cost due to competition from accumulated demand for iron production and limiting resources, method attracted iron making industries and appealed its value.

PCI method is based on simple concept that primary air (termed as conveying gas) carry pulverized coal through the lance in tuyere (mid bottom side inlet of blast furnace), then mix with secondary hot air (termed as blast) supplied through blowpipe in tuyere then to furnace and creating ballon like cavity called “raceway”, then propagates coal, coke combustions and melts solid iron ore and reduce it to liquid iron. The most remarkable of the method was that method allows for cheaper coal to be consumed in system to replace expensive coke; as a result, it can remarkably save cost. Although due to severe environment inside the furnace (>2000K), visual observations of raceway shape and size is impossible therefore numerical method is preferred to virtually investigate the chemical and physical phenomenon inside furnace.

Better understanding of raceway and PCI method can optimize the performance of blast furnace and reduce the cost. In recent years, further improvement of PCI method, use of coal blends (mixing multiple different coals) injection method are strongly attracting industry.