Decarbonization in the Steel Industry Part 2: Charcoal as Fuel and Reductant in Blast Furnace

Basically, the conditions in each steel industry vary so that the decarbonization process is also carried out using different and gradual routes to achieve net zero emission conditions. The conditions of each steel industry have a unique configuration of production technology, raw materials and energy sources, capacity and yield, regulatory requirements and so on. To achieve Net-zero by 2050, a number of things need to be done, such as efficient use of raw materials, increasing the portion of reuse and recycling, retrofit and advanced technology, and especially efforts to use renewable energy sources as fuel and reductant in the iron and steel industry. But the fact is that the construction of blast furnaces - basic oxygen furnaces (BF -BOF) is still being carried out, which should be EAF (Electric Arc Furnace) or currently only around 30% of the global iron and steel industry uses this EAF, but there are transition efforts that can be made as described below. The transition is influenced by market demand, policy interventions, and incentives given to producers to reduce emissions in steel production.

To create policies related to this transition, providing incentives to reduce emissions for producers and creating market demand for "green steel", a clear definition is needed between low emissions vs. almost zero emissions (near zero emissions) vs zero emissions (net-zero emissions). It is estimated that in 2021 CO2 gas emissions from this industry will be 3.8 Gt globally (this has not even taken into account methane emissions from coal mining). Meanwhile, for Net-zero 2050 conditions, direct CO2 emissions from the global iron and steel industry must be reduced to 1.8 Gt CO2 in 2030 and 0.2 Gt in 2050. It seems that a lot of hard work is still needed to achieve this target, even with the current conditions. Many people are pessimistic.

One use of biomass as a carbon neutral fuel in the iron and steel industry is the use of charcoal as a fuel and reductant. Biomass such as wood must be carbonized or pyrolyzed to become charcoal. The use of charcoal in blast furnaces not only reduces carbon dioxide (CO2) emissions, but also sulfur dioxide (SO2) emissions because the sulfur content of charcoal is very low (around 100 times lower) than coke. Likewise, the use of limestone will decrease so that slag production will also automatically decrease. Likewise, it makes the blast furnace operation acidic.

Apart from a number of advantages obtained as above, it turns out that there are drawbacks to using charcoal in blast furnaces, namely in large blast furnaces which causes operational problems because the strength of charcoal is usually lower than coke. As a solution, there are three methods of using charcoal in the blast furnace process. First, with pulverized charcoal injection (PCI). With this method the charcoal must be crushed into a powder and injected into the blast furnace. Second, with charcoal powder mixed with coke powder into pellets or briquettes called charcoke. By making this charcoke, its strength is sufficient for use in conventional blast furnaces. And third, by replacing coke with lump charcoal for small capacity blast furnaces (inner volume 60 – 550m3). In small capacity blast furnaces, the compression pressure on each charcoal particle is much smaller than in large capacity blast furnaces. Sintering and pelletisation are not required in this case.

Energy plantations or biomass plantations can be created specifically to supply raw materials for charcoal production. The energy plantation will also absorb carbon from the atmosphere (carbon sink) in a certain volume. The volume of carbon from the atmosphere can be maintained in such a way that its function as a carbon sink can be carried out, namely by the amount of wood harvested for charcoal production not exceeding the growth rate of the wood biomass. In this way, the energy plantation cannot be finished in one harvest but is sustainable while maintaining its volume or area.

With continuous pyrolysis technology, charcoal production can be optimized. With this continuous pyrolysis technology, apart from the large charcoal production capacity, multi-use by-products are also produced, such as gas products which can be used as an energy source as well as biooil. Biooil can also be used as a raw material in the chemical industry. Charcoal production of tens to hundreds of tons per day is also possible with continuous pyrolysis technology.

And especially in Indonesia, as the owner of the largest oil palm plantations in the world, which is estimated at more than 15 million hectares and with palm oil mills reaching around 1,000 units, there is a lot of palm oil waste that can be utilized, especially empty palm fruit bunches or EFB (empty fruit bunch). The potential for charcoal production from EFB is also very large. Apart from that, as the 5th largest coal producer in the world with production of around 570 million tons per year, coal also needs to be processed into coke. Charcoal from empty bunches or EFB can be made into powder for PCI or into charcoke by compacting it, namely making pellets or briquettes with coke.

Young Coconut Waste Processing: Briquetted or Pelleted!

When the weather is very hot like recently, drinking coconut water is very refreshing. This is because coconut water, apart from meeting the body's fluid needs, also meets the needs of electrolytes (ionically charged minerals found in cells, tissues and body fluids) which the body really needs. This electrolyte plays a role in supporting the activity of cells and body tissues and maintaining the balance of body fluid levels. When the body loses electrolytes due to physical activity or dehydration, consuming coconut water can help replace lost electrolytes and restore body fluid balance. There are many sellers of young coconut ice, especially in big cities. Apart from being sold in glasses, young coconut water is also sold in the form of whole young coconuts. The combination with young coconut flesh adds to the deliciousness of the drink. But it turns out that the waste from young coconuts is very polluting and has not been processed or used properly. The volume of young coconut waste is quite large, in fact, in the city of Makassar, South Sulawesi,  it is estimated that there is 15 tons/day of young coconut waste.

Young coconut waste can be processed into briquettes or pellets. Biomass densification technology is suitable for application as a solution for young coconut waste. The young coconut waste needs to be reduced in size (size reduction), namely with a shredder and hammer mill, then dried with a dryer before being compacted / densified into briquettes with a briquetting machine or into pellets with a pelletiser (pelleting machine). By briquetting or pelletizing the waste, it can be used as fuel or energy source for SMEs or boilers in industry. Many SMEs or processing industries can use this fuel. Apart from being environmentally friendly, it is also easy to use. Simple furnaces can be developed to use these briquettes and pellets.

Indonesia is famous for its seductive land of coconut islands. This is because the extent of coconut plantations in Indonesia reaches around 3.7 million hectares, most of which are smallholder plantations. The extent of these coconut plantations places Indonesia as the owner of the largest coconut plantations in the world. Coconut trees mainly grow along the coast, and indeed Indonesia also has the second longest coastline in the world, after Canada.

Buy Wood Pellets or PKS (Palm Kernel Shell)?

The need for biomass fuel as a decarbonization effort because it is a renewable fuel that is carbon neutral is increasing. Two biomass fuels that are popular in the world and compete fiercely are wood pellets and palm kernel shell (PKS). Under normal conditions or without a spike in demand, the price of wood pellets is usually more expensive than PKS. This is understandable because wood pellet production requires more effort than PKS. Wood pellet production requires a number of equipment with an expensive investment, while PKS only requires minimal equipment, namely just a screening/sieving machine.

But what if the prices of wood pellets and PKS are almost the same or even PKS is even more expensive? This can happen due to several factors, namely first, the influence of market demand. High market demand, especially PKS from Indonesia and Malaysia, means supply is reduced or inadequate. PKS production in Indonesia and Malaysia is indeed much greater than wood pellet production from these two countries. Apart from the larger production volume, factors such as availability and continuity (long-term security of supply) can be guaranteed more than wood pellets. This is because it is estimated that there are 1500 palm oil mills in Indonesia and Malaysia that produce PKS which is a by-product or waste of palm oil mills. This allows for long contracts between sellers or suppliers (exporters) and buyers who are usually not end users but trading companies in Japan and Korea.

Loading PKS for export with transhipment (ship to ship)

The second factor is levy and tax. PKS exports in Indonesia are subject to levy and tax whose value is correlated with the price of crude palm oil (CPO). This is because PKS in Indonesia is included in the palm oil derivative product category, whereas in Malaysia it is not subject to these levy and tax, because PKS in Malaysia is included in the palm oil waste category. When levy and tax are high, the price of PKS will automatically become expensive. This levy and tax factor is something that PKS exporters cannot control. Through the APCASI organization (Indonesian Palm Kernel Shell Entrepreneurs Association) they are fighting for levy and tax to be more measurable or cheaper, even if they can be eliminated like in Malaysia.

Basically buyers will buy the best possible goods at the cheapest possible prices, or better quality goods but cheaper prices. The quality of wood pellets is better than PKS, namely in terms of calorific value, ash content, shape uniformity and moisture content. However, due to volume factor and continuity (long-term security of supply) which are often or still widely in doubt, the choice to go to PKS is still being made. To overcome this, wood pellets production must meet production capacity with a reliable source of raw material supply. Production of wood pellets from energy plantations is the solution.

With wood raw materials from energy plantations, the supply of raw materials will be more stable, unlike those that rely on collecting wood waste from sawmills or wood processing industries. With Indonesia's production forest area reaching tens of millions of hectares, of course land is not a problem in wood pellet production. Wood pellet production centers can be created on these production forest lands, for more details, you can read here.