Large Capacity Wood Pellet Production Cannot Be Done on Java Island?

Raw materials are a vital aspect of a production activity. No raw materials means no production. Likewise in the wood pellet industry. The availability of raw materials is absolutely necessary for the continuity of the wood pellet business. To maintain the supply of raw materials, wood pellet factories must have reliable sources of raw materials. Currently, most or even all wood pellet factories on the island of Java rely on sources of raw materials for wood pellet production from wood waste, especially sawdust from sawmills and wood processing industries. 

Currently, coal-fired power plants in Java are running a coal cofiring program with biomass to reduce carbon dioxide emissions or decarbonization. The use of coal in these power plants will be reduced while the use of renewable energy, especially biomass, is increased. The biomass currently used for cofiring is sawdust with a volume of up to hundreds of thousands of tons per year. A very large amount. Wood pellet factories that use sawdust as raw material must compete with the cofiring program in these power plants. This competition increases the price of sawdust because the supply remains the same but demand increases. Disruptions in the supply of raw materials in these wood pellet factories result in disruptions in production and automatically their business aspects.

With these conditions, large-capacity wood pellet production in Java Island becomes less attractive. In fact, the portion of biomass use, especially sawdust, will continue to increase along with the decarbonization program to achieve net zero emissions by 2060. This is increasingly burdensome for wood pellet factories that rely on raw materials from buying sawdust. Wood pellet factories in Java can run well if the availability of raw materials can be maintained and this can only be realized in two ways, namely first using their own raw materials, this can be done by sawmills and wood processing industries that utilize their own waste for wood pellet production, and secondly with raw material sources from energy plantations. Energy plantations that are specifically dedicated to wood pellet production will be able to maintain the stability of the supply of raw materials for wood pellet factories. Wood pellet factories can partner with Perhutani for the second point above.

Green Economy in the Cement Industry Part 3

Fly ash is a byproduct or waste of coal power plants. Like slag, fly ash is also an additive or supplement (SCM/supplementary cementious material) in cement production. The difference is that fly ash is very fine so it doesn't need to be refined anymore and can be mixed directly with clinker and gypsum. Every ton of fly ash used prevents about 1 ton of carbon dioxide (CO2) from escaping into the atmosphere. This is in line with the green economy or decarbonization as a climate solution effort for the industry.

Unloading fly ash

As the same with slag, the chemical content of fly ash also influences the quality of the cement produced, for example certain regions or countries have requirements for grade 120 alumina in the slag. Cement with a certain quality can be designed with the use of these additives. In the current era, apart from technical factors such as mechanical strength or cement adhesion, microstructure, durability and so on, and economic factors, environmental friendly product factors are also a concern or have their own positive image. Circular economy in the form of utilizing waste from other industries to become raw materials for this industry, also occurs in the cement industry. And basically the cement industry besides being able to process waste is also a waste destroyer.

Biomass Pellets in India

India has hundreds of millions of biomass waste, especially from agricultural wastes or about 230 million tons per year. Hundreds of millions of tons of biomass waste is of course an environmental problem, especially because most of the waste is simply burned in fields where the smoke pollutes the environment, but on the other hand it will be a solution, namely for decarbonization programs and climate change. Technically, the biomass waste from agricultural waste will be processed into fuel pellets (biomass pellets) which are used for fuel in power plants by cofiring. In the early stages, the Indian government targeted 5% for the cofiring ratio in their coal power plants, where the 5% figure when translated into biomass pellet production would reach around 50 million tons of biomass pellets per year. This is a very large amount, especially with a short time target, which is only one year since it was ordered on October 8, 2021 and will take effect in October 2022 or this year, so hard efforts are needed to achieve this target. Meanwhile, in 2021, the world's demand for wood pellets for power plants will only be around 23 million tons.

The establishment of factories for the production of biomass pellets must be carried out immediately to achieve the production target. These factories must also be supported by logistical readiness to supply raw materials so that the factory can be completed, so that the production of biomass pellets can be carried out as soon as possible. With an average power generation capacity of 275 MW in India, with a cofiring ratio of 5%, the annual need for biomass pellets is estimated at 50 thousand tons or 170 tons per day. With the number of power plants reaching around 900 units with an average consumption of 50 thousand tons of biomass pellets per year or a total of almost 50 million tons per year, the distribution of biomass pellets is also a challenge. A factory with a capacity of around 5 thousand tons/month is likely to be suitable, and even if each factory supplies one power plant, the need for a biomass pellet factories will also be the same as the number of power plants, which is 900 units. A huge amount.

Biomass pellets or agri-waste pellets, namely pellets from agricultural wastes do have a number of differences with wood pellets. Wood itself is also a part of biomass so it can also be called biomass pellet. Biomass has a wider range, including wood pellets and agri-waste pellets. Agri-waste pellets have higher ash content, and some have higher chlorine, potassium and silica content in the ash. The content of these substances is not friendly to the heat exchanger pipes in the boiler which will cause fouling and corrosiveness, so that in addition to decreasing boiler efficiency, the service life of the boiler is shortened. In addition, the harvest of agricultural products usually coincides at certain times, while the pellet factory must continue to produce every day. This is why it is necessary to store and allocate raw materials in the form of agricultural waste for the routine production of these pellets. And because these agricultural wastes cannot be left alone in the agricultural area, they need additional investment in the form of storage warehouses and to be able to store more agricultural waste they need to be temporarily compacted by baling. These things usually don't happen in wood pellet production, so the agri-waste pellet production approach is different.

And because the ash chemistry of agricultural wastes causes many problems in the operation of power plants, their use is also limited. With a cofiring ratio of 5%, the problem can still be tolerated, but when the ratio is enlarged, the impact will be more pronounced. The exception is the CFB (circulating fluidized bed) type plant which can use 100% of the agricultural waste pellets, but in India the power plants using CFB technology are very small, around 1% (9-10 units). Indonesia and Malaysia also produce biomass fuel that is almost similar to pellets and even in the international market is the pellet competitor, namely palm kernel shells or PKS. The volume of PKS also reaches millions of tons, so it can be exported to India to help meet India's needs for biomass pellets, which so far have been mainly for export to Korea and Japan. PKS is also produced by a number of countries in West Africa. But it seems that the Indian government for now will prioritize the use of their agricultural waste first, so it has not provided financial support for the import of the biomass fuel.

Currently, India must make every effort to accelerate the construction of biomass pellet factories to achieve this target. However, 1 year to achieve this target is very difficult. With these conditions in the future, it is possible that power plants in India will import biomass fuels such as wood pellets and PKS to meet their needs. With the currently planned cofiring ratio of 5%, the need for biomass pellets reaches around 50 million tons, if only 2% of the biomass fuel needs are imported, both PKS and/or wood pellets, it will reach 1 million tons, the amount is still very big.

Cofiring Biomass at a Steam Turbine Gas Power Plant, Is It Possible?

 Cofiring technology is divided into several types, namely direct cofiring, indirect cofiring, and parallel cofiring. The choice of using the cofiring type is mainly related to the type of fuel and combustion technology used. In general, based on its form, fuel is divided into three namely solid, liquid and gas fuels. The form of the fuel affects the combustion technology used. Liquid fuel which is a fluid, then combustion with a burner. Whereas fuel for combustion technology with fixed bed, fluidized bed and pulverized combustion. Mixing solid fuels such as biomass especially PKS / palmkernel shells, wood pellets and wood chips with coal is usually done in the direct cofiring type and this is the most common cofiring type. Then how about cofiring biomass with biomass fuels that are solid form with fossil fuels that are liquid or gas?

Steam Turbine

Fossil fuels such as diesel oil and gas such as natural gas usually used to fuel power plants in internal combustion engines (IC engines) whose output is mechanical energy to drive generators. Gas engine is an IC engine that is commonly used for the production of electricity from gas fuels such as natural gas. But if diesel oil or natural gas is used on external combustion engines (EC engines) such as furnaces and boilers that produce steam. Steam will then drive the turbine that is connected to the generator. In the EC engine cofiring mechanism can be done namely parallel cofiring type. In this mechanism, biomass as will be used to produce steam for additional steam from the fossil fueled EC engine.

Avedore Power Plant, Denmark

An example of a biomass cofiring with a gas power plant is the Avedore Unit 2 power plant, which is located in Denmark near Copenhagen. The power plant operates at ultra-supercritical with a capacity of 430 MW using steam turbine with natural gas fuel and is also equipped with 2 gas turbines with a capacity of 51 MW each. The gas turbine is used to provide electricity at peak load and boiler feed water via the exhaust heat recovery unit. Whereas a biomass boiler with a capacity of around 50 MW is used to provide additional steam to the system. The biomass boiler burns straw at a consumption of 150 thousand tons per year and produces 40 kg / second of steam at 583 C and pressures up to 310 bar.