Biomass Boiler Testing and Selection of Suitable Biomass Fuel

In line with the trends toward decarbonization and sustainability across various sectors of life, particularly in the processing industries (manufacturing/process industries), the use of biomass boilers has become a realistic option today among boilers that utilize other renewable energy sources. Fossil-fuel-fired boilers—such as solid-fuel boilers (coal), liquid-fuel boilers (industrial diesel), and gas-fired boilers (natural gas)—must be replaced with renewable fuel boilers, namely biomass boilers. Apart from technical factors in the form of operational adjustments from previous fossil-based fuels, the suitability and availability of biomass fuels are important factors. Suitability refers to the technical aspect and availability refers to the economic aspect.

Combustion technology for biomass boilers also continues to develop so that efficiency continues to increase. From the beginning in the form of static grates to dynamic moving grates such as chain grates and reciprocating grates, even fluidized beds. And to get optimal performance, biomass fuel specifications must also match the shape, size, calorific value and dryness. If the specifications do not meet the requirements of the combustion technology in the boiler then of course the performance will not be optimal. For example, chain grates are suitable for using fuel that has a uniform size and low water content such as palm kernel shells, wood chips and wood pellets. Apart from that, biomass fuel with ash content which has a high melting point is highly preferred so that the ash does not melt and clog the chain lattice cavity.

Meanwhile, using a reciprocating grate, this system is very reliable for burning biomass with high moisture content (up to 60%), non-uniform size, and high ash content, such as empty oil palm fruit bunches (EFB), bark, and municipal solid waste (MSW). The combustion system moves back and forth periodically (like a moving staircase that moves back and forth) which functions to mechanically turn and stir the fuel. And for fluidized beds, this system has the highest thermal efficiency (>89%) and is very suitable for biomass with very small size (powder/dust), low calorific value, or fluctuating chemical content such as rice husks, sawdust, and coffee grounds. The biomass particle size must be maintained within certain limits so that it can float and fluidize perfectly with the sand bed media. The ideal particle size for a fluidized bed boiler (FBC) generally ranges from 0.1 mm to 10 mm (maximum 30–50 mm for certain components), depending on the specific type of technology used.

As a country located on the equator with a tropical climate, Indonesia is a biomass paradise in the world; read more here. A wide variety of biomass fuels in large volumes can be sourced in Indonesia. The most readily available biomass fuels in Indonesia today are wood chips, palm kernel shells, and wood pellets. Wood briquettes are also available but in limited quantities. Choosing the right biomass fuel will ensure optimal boiler performance, but of course, the economic factors for each metric ton of high-pressure steam produced are equally important. 

Ideally, biomass fuel is available in large quantities, ensuring affordability and high quality. The price of biomass fuel is influenced by various factors, including availability, location, logistics infrastructure, and transportation costs. Furthermore, if the biomass fuel undergoes processing, such as wood pellets and briquettes, production costs also contribute. Palm kernel shells for industrial boiler use in Indonesia require almost no processing; they are simply collected from palm oil mills or CPO mills, which produce waste in the form of palm kernel shells (PKS).

There is a case study regarding the selection of this biomass fuel involving a multinational company. In a certain country, the company’s boilers operate using wood briquettes—specifically, industrial briquettes produced by a mechanical press. This approach was also planned for the company’s plant in Indonesia. However, because producers of wood briquettes are still very scarce in Indonesia—making it impossible to secure a supply—the company ultimately conducted various experiments and trials with different types of biomass fuels and now operates its boilers using wood pellets. Thus, in addition to technical factors, economic factors are also crucial for ensuring optimal and sustainable biomass boiler operations. The trial phase is a critical step in achieving these conditions. 

Environmentally Friendly Boiler Feedwater Treatment in Palm Oil Mills & More in Line with Sustainability Missions

As the decarbonization trend continues to penetrate various sectors of life, various efforts aligned and relevant to decarbonization and aspirations will become a concern, even a choice, and even an obligation. Sooner or later, these climate-smart efforts will become increasingly accepted and an integral part of human life. The upstream palm oil industry (particularly palm oil mills/CPO mills) is no exception. With the use of biomass fuel for boiler operations, which outputs high-pressure steam for palm oil mill operations and electricity production, from a climate perspective, the palm oil industry contributes approximately 1.4% of carbon emissions to the atmosphere.

Emissions from the palm oil industry primarily come from carbon loss during land clearing/deforestation, emissions from peat drainage, and emissions from palm oil mill effluent (POME). In addition, there are also emissions from the use of vehicles for transporting raw materials and palm oil products, as well as for plantation operations (soil cultivation, fertilization, harvesting, etc.), and during palm oil mill start-up. Compared to other sectors, such as energy, power generation is the largest global contributor of emissions at 29%, followed by industry (cement, steel, chemical, etc.) at 21%, and transportation (land, sea, and air) at 15%. Although the global palm oil industry is quantitatively small at 1.4%, in the NZE (Net Zero Emission) effort, it must still be reduced.

This also includes the water treatment sector. In palm oil mills/CPO mills, where steam generated from boilers is used not only for electricity generation but also for mill operations, water treatment, especially for boiler feedwater (BFW), is crucial. Water is likened to blood for the human body. Environmentally friendly water treatment, without secondary pollution and without chemicals, is predicted to become a new trend in this era of decarbonization and sustainability. The high water quality specifications required for boiler feedwater (BFW) require a series of water treatment unit operations. In addition to being clean and clear (TDS <700 ppm), it must also have low hardness, mineral content, and oxygen content.

A number of equipment such as ion exchangers, activated carbon filters, RO membranes, and deaerators are used to produce boiler feedwater (BFW). For an environmentally friendly water treatment process that is more in line with the sustainability mission, the electrochemical method is the solution. By using the principle of redox reactions (reduction and oxidation), electrochemical cells will produce ions capable of sterilization, deodorization, scale prevention, rust protection, decomposition of organic compounds that are not easily biodegradable, remove heavy metal ions, remove residual chlorine, remove residual insecticides, and so on. The use of this method will also save or extend the service life of ion exchangers, activated carbon filters, and especially the RO membrane.

This not only provides environmental and sustainability benefits but also economic benefits. Technical and economic comparisons can also be made between conventional and chemical methods and this electrochemical method. Please contact us if you'd like to make such a comparison, and we'll create a simulation. Besides the longer lifespan of boiler feedwater treatment equipment, which requires less frequent cleaning, another important piece of equipment that can be saved or extended is the boiler. Boilers, which have a lifespan of around 15-20 years, can also last 30% or even more, depending on a number of factors, including water conditions.

Related to decarbonization and sustainability, the palm oil industry is also currently moving towards electric vehicles in the plantation sector. The use of electric vehicles has the potential to provide added value, especially for companies that have obtained sustainability certifications such as the RSPO (Roundtable on Sustainable Palm Oil) and ISPO (Indonesia Sustainable Palm Oil). The use of electric vehicles allows palm oil companies to claim fossil fuel reduction and benefit from sustainability aspects. Technically, when charging the electric vehicle's battery, it comes from renewable energy sources, namely electricity produced by palm oil mills that use biomass fuel (fiber and palm kernel shells) as their energy source, and not from PLN (Indonesia state owned company electricity) , which uses fossil fuels like coal. 

Palm Oil Mill: Just Replacing Boiler? Or Are You Also Looking for a Solution to Address the Problem of Empty Fruit Bunches and Generate Additional Profits?

As palm oil plantations in Indonesia continue to expand—currently covering approximately 17 million hectares—the demand for palm oil mills is also increasing. About 10 years ago, there were approximately 1,000 palm oil mills in Indonesia, but according to the latest data from the Ministry of Agriculture of the Republic of Indonesia, the number of active palm oil mills (POM) in the country is now estimated to be between 1,200 and 1,500. These palm oil mills are primarily located on Indonesia’s two largest islands: Sumatra (52.69%) and Kalimantan (42.71%), while the remainder are in Sulawesi, Papua, and several other islands, where their presence is relatively small (each accounting for less than 3%). In terms of ownership, the majority of palm oil mills in Indonesia are owned by large private companies (93%), with the remainder owned by state-owned enterprises (7%). A single large private company may own a dozen or even dozens of these palm oil mills. 

One of the main equipments for palm oil mill operations is the boiler. In fact, given the current palm oil mill production process, boilers are mandatory for palm oil mills; more details on the reasons can be found here. Boilers can also be considered the "heart" of a palm oil mill, converting water into high-pressure steam to run the production process and generate electricity for the mill and its employee housing. Like all production equipment, boilers have a lifespan. When a boiler's lifespan is exceeded, it becomes not only uneconomical due to high maintenance and operational costs, but also dangerous.

The average lifespan, which is the technical and economic life of a palm oil mill boiler, is 20 years. Once this lifespan is exceeded, investing in a new boiler becomes more profitable. The majority of palm oil mills in Indonesia use water tube boilers (e.g., Takuma or Vickers). This type of boiler circulates water through hundreds of externally heated pipes fueled by palm oil waste in the form of shells and fibers. Because these pipes interact directly with extreme heat and water scale, these internal components wear out most rapidly. The three main factors affecting the boiler's lifespan are boiler feedwater quality, fuel characteristics, and regular maintenance.

When the time comes to replace the boiler, and considering the mountains of unused empty fruit bunches (EFB), palm oil mills might consider using them as boiler fuel. But given their large size and high moisture content (>60%), how can they do that? This is certainly a reasonable and innovative idea, given the urgency of replacing the boiler and simultaneously facing the problem of biomass waste. Technically, as biomass waste, it can certainly be used, but is it economically feasible to treat or prepare the empty fruit bunches (EfB) until they are ready for use as fuel? This is the challenge.

Proven evidence will dispel any doubts or theoretical narratives. Likewise, a unit that can process empty fruit bunches (EFBs) and also serve as an additional energy source for boiler operations (cogeneration) at the palm oil mill. With this equipment, not only can the problem of empty fruit bunch (EFB) biomass waste be resolved, but the palm kernel shells (PKS), which have been used as boiler fuel along with the fiber, can be 100% sold directly, providing a source of income. Furthermore, the potassium-rich ash content of empty fruit bunches (up to 30%) also has the potential to be used as fertilizer, including for use on the palm oil plantation. For more details, please read here. Visiting and observing the unit in action can also serve as a means of proving the point, thereby increasing the confidence of palm oil mills interested in this solution.

Beyond technical factors, economic considerations will undoubtedly be a crucial consideration in implementing this equipment. By considering several factors, particularly those currently operating in the palm oil industry, a comprehensive and accurate economic analysis can be conducted to reach a decision on use of the equipment. In an era of renewable fuels, efficiency, zero waste, and increased profitability, this equipment, which serves as a supplemental energy source (cogeneration) for the palm oil mill's boiler, is worth considering for palm oil mills currently facing boiler replacement. 

Electricity Production from Pyrolysis, Using a Gas Engine or ORC Generator?

The more efficient the equipment, the greater the benefits or profits that can be obtained. This includes equipment for biochar production, namely pyrolysis. The more efficient the pyrolysis equipment, the cheaper it will be to produce biochar but also produce development products. An example is the use of byproducts from the pyrolysis process such as syngas, biooil, pyroligneous acid and excess heat. Harvesting or utilizing energy from waste heat sources that would normally be wasted is also part of efficiency as well. A number of products that can be used for energy production can be used for electricity production, namely syngas, biooil and excess heat. But there are a number of technologies for producing electricity, so which one do you choose?

A. Gas Engine

Gas engines such as the GE Jenbacher are commonly used to produce electricity from biogas. Biogas, which is a product of bioprocess, has a very dominant methane gas content, while syngas from pyrolysis, which is a thermal process, contains only a small amount of methane and more hydrogen (H2) and carbon monoxide (CO), this means that gas engines are not suitable for producing electricity from syngas pyrolysis. Apart from being suitable for biogas, gas engines such as the GE Jenbacher are also suitable for natural gas, which also contains methane gas.

B. ORC (Organic Rankine Cycle)

The main difference between the Organic Rankine Cycle (ORC) and the ordinary Rankine cycle lies in the working fluid and the temperature of the heat source used. ORC was specifically designed as a modification of the conventional Rankine cycle. The difference with the ordinary Rankine Cycle which uses steam from the boiler as the working fluid which is widely used in large capacity coal powerplants, the ORC uses a working fluid in the form of an organic fluid which has a low boiling point such as hydrocarbons or refrigerants. This low boiling point means that you can use a heat source whose temperature is not too high, such as waste heat or residual heat and so on.

And because there are many organic fluids available, selecting organic materials as suitable working fluids for ORC is no less important. In fact, the choice of working fluid for the ORC generator is very crucial because it affects thermodynamic efficiency, operational costs and safety aspects. The main factors considered are the thermophysical properties of the fluid, compatibility with the heat source, environmental impact, and commercial availability (economic aspects). So the selection of ORC fluid must balance energy efficiency, safety, environmental impact and cost.

Waste heat from pyrolysis can be recovered and used for electricity production with this ORC. Likewise, pyrolysis byproducts that can be used as energy sources are excess syngas and bio-oil. The excess syngas and bio-oil are used as fuel and the heat is used as an energy source for the ORC generator. Basically, the selection of an ORC power plant is based on electricity needs and available energy sources. 

For small electricity needs, namely in the range of 0.5 MW - 10 MW and low temperature energy sources, namely those whose temperature is below 350 C (low to medium temperature range (80 C - 350 C)), then the choice of ORC is suitable. As a comparison, steam turbines require temperatures well above 400 C and a power output of 10 MW to above 1,000 MW (as in coal-fired power plants or nuclear power plants). But why do almost all palm oil mills (CPO / crude palm oil mills), even though their electrical power production is small or an average of less than 5 MW, still use steam turbines? For an explanation, read here.

The application of an Organic Rankine Cycle (ORC) generator as waste heat to power (WHP) from the pyrolysis process is a very effective combination to increase the total energy efficiency of the system (co-generation). And modern pyrolysis units are widely used in continuous system biomass pyrolysis, namely for biochar production, which work autothermally or self-sustainably, so it is possible that the pyrolysis unit can also operate independently from the electricity generator from the ORC. This means it will reduce operational costs, because the electricity to run electric motors, pumps and so on comes from its own production. In other words, the pyrolysis unit operates independently without depending on the electricity network or PLN (Indonesia state owned company). From a climate perspective, these conditions are ideal, because the energy source comes from renewable sources (carbon neutral) and if biochar is used for carbon sequestration it means it is carbon negative. Optimizing the system so that it produces an optimal and profitable configuration is the task of engineers.

An American company, namely Quonset Soil Solutions, LLC in Rhode Island, has recently successfully installed an ORC unit to harvest waste heat from their pyrolysis unit with a capacity of 1.8 MW. Apart from that, several pyrolysis units in Europe are also reported to be using ORC with a smaller capacity. These successes will inspire and the installation of ORC units as part of biochar production with (slow) pyrolysis will continue to grow.

Conclusion:
-The ORC system is highly recommended for continuous scale pyrolysis plants (not small batch types) because it is able to convert heat pollution (waste heat) into valuable electrical energy assets constantly. ORC operations are environmentally friendly and support decarbonization targets.

-The ORC generator from waste heat pyrolysis is an efficient, safe and sustainable solution for generating electricity from waste heat energy (residual heat). This technology is also ideal for various industries that produce intermediate heat, so that energy is not wasted.

Biochar Needs for the Iron and Steel Industry

As awareness of climate change and global warming grows, along with the Paris Agreement and Net Zero Emissions (NZE) 2050 targets for decarbonization, the use of biomass to produce biocarbon products is increasing. The iron and steel industry, in particular, faces significant demand, while supply remains limited. This has prompted several large companies to invest in large-scale biocarbon production, particularly biochar/biocoke.

Such large-scale production naturally requires abundant biomass feedstock. Specifically, in Indonesia, biocoke/biochar production from palm kernel shells (PKS) reportedly began last year. PKS was chosen because it is a readily available biomass waste product from palm oil mills. PKS and palm oil mill production in Indonesia is estimated to be around 12.5 million tons/year, but because some of the PKS is used as boiler fuel, the estimated usable PKS or remaining boiler fuel is around 6.25 million tons/year. To increase the supply of PKS from palm oil mills, cogeneration of empty fruit bunches (EFB) can be used. For more details, read here.

In addition to the PKS, biocoke/biochar and even black pellets (torrified pellets) are also produced using wood from energy plantations. Energy plantations with short-rotating crops like calliandra and gliricidia have great potential to produce this wood. Currently, wood pellets (white pellets) are being produced from these wood plantations. For more details on whether wood from energy plantations is better for wood pellets (white pellets) or biocoke/biochar/charcoal, read here.

Biocoke, biochar, and charcoal are used in the iron and steel industry as a substitute for coal-based coke in blast furnaces, while wood pellets (white pellets) and torrified pellets (black pellets) are used in power plants using both cofiring and fulfiring. In addition to their higher calorific value (around 20% higher than wood pellets (white pellets)), torrefied pellets (black pellets) are also hydrophobic, allowing them to be stored outdoors, like coal.

In today's era, the use of biocoke / biochar / charcoal to replace coal coke in blast furnaces is becoming important. Biocoke / biochar / charcoal derived from biomass is a renewable material that is sustainable as a reducing agent or fuel in blast furnaces. The chemical reaction will separate oxygen atoms from iron atoms and this will emit CO2. This will convert iron ore (Fe2O3) into crude (pig) iron.

However, the difference lies in the fact that the carbon source used as a reducing agent or fuel in a blast furnace comes from renewable and sustainable sources, making it a carbon-neutral process. Conversely, using coke from coal, as it comes from a fossil source, makes it a carbon-positive process. Similarly, using natural gas, a fossil fuel, as a carbon source for the reducing agent or fuel in a blast furnace, despite its lower carbon intensity, is considered less carbon intensive. 

Washed PKS for Decarbonization of Iron and Steel Plants

The steel industry contributes 8% of global CO2 emissions, with each ton of steel produced producing an average of 1.85 tons of CO2 emissions. Compared to iron ore mining, iron and steel production contributes significantly more to CO2 emissions. Decarbonization efforts in the steel industry begin with the use of renewable energy for smelting. Biomass-based fuels, such as charcoal, which has a high carbon value, can replace the use of coke derived from coal. The use of hydrogen from renewable energy sources is the ultimate decarbonization target for the steel industry.

Currently, the steel industry largely uses coal as an energy source or reducing agent. This coal is processed into coke and used in blast furnaces. It is estimated that approximately 70% of global steel production uses the blast furnace or BF-BO process, and in China, over 90% of steel production uses the BF-BOF process. To reduce carbon intensity, natural gas is used as the fuel. The use of natural gas as a gaseous fuel also acts as a transition medium and, because it is derived from fossil fuels, is also a carbon-positive fuel.

Nearly all CO2 emissions in the steel production sector come from blast furnaces (BFs), which refine iron ore into crude iron or pig iron. The challenge is significant: there are approximately 1,850 steel mills worldwide, with approximately 1,000 using blast furnaces, producing approximately 1.5 billion tons of pig iron annually.

The use of charcoal in a blast furnace not only reduces carbon dioxide (CO2) emissions but also sulfur dioxide (SO2) emissions due to its very low sulfur content (approximately 100 times lower) than coke. Likewise, the use of limestone is reduced, thereby automatically reducing slag production. This also makes the blast furnace's operation acidic.

The use of biomass-based carbon fuel (biocarbon) in the form of charcoal has a better climate impact because it is carbon-neutral. Furthermore, technically, because it is a solid fuel, similar to coke derived from coal, it requires little or no changes or modifications to the smelting furnace. However, the availability of high-quality charcoal, large volumes, and a continuous supply remain major constraints.

This makes the use of charcoal to replace coal-based coke in blast furnaces crucial. Charcoal, derived from biomass, is a renewable, sustainable material used as a reducing agent or fuel in blast furnaces. The chemical reaction separates oxygen atoms from iron atoms, emitting CO2. This converts iron ore (Fe2O3) into crude (pig) iron.

However, the difference lies in the fact that the carbon source used as a reducing agent or fuel in a blast furnace comes from renewable and sustainable sources, making it a carbon-neutral process. Conversely, using coke from coal, as it comes from a fossil fuel, is a carbon-positive process. Similarly, using natural gas as a carbon source for reducing agents or fuel in a blast furnace, although it is said to have lower carbon intensity, is also considered a carbon-neutral process.

The use of charcoal or biocarbon materials for metallurgy or steelmaking has actually been commonplace for some time. In the early 1900s, global charcoal production reached its peak, exceeding 500,000 tons. In the 1940s, charcoal production declined to nearly half its early 1900s levels due to the replacement of other carbon materials, such as coke from coal, in the manufacture of steel and other metals.

Charcoal is a fuel and reducing agent derived from biomass that has significant potential for use during this transition phase. Palm kernel shells (PKS) are a potential biomass raw material for charcoal production. Palm kernel shells (PKS) are available in the millions of tons, ensuring a reliable supply. Charcoal, a product of biomass carbonization or pyrolysis, has a high calorific value, high fixed carbon content, and stability. However, another factor, ash chemistry, influences the quality of the resulting steel. This is somewhat similar to the ash chemistry of wood pellets from calliandra or gliricidia energy plantations.

When used as a reducing agent in blast furnaces, charcoal must have a low phosphorus content, while wood pellets from calliandra or gliricidia energy plantations must have low potassium, sodium, and chlorine content. The potassium, sodium, and chlorine content of wood pellets affects the quality of the wood pellets and their use in power generation. Pulverized combustion power plants, widely used worldwide, will reject wood pellets with this quality. Similarly, blast furnaces will reject charcoal with a high phosphorus content.

To achieve this quality, low-phosphorus content, the palm kernel shells (PKS) must first be washed. After washing, the phosphorus content decreases, and they are then dried and pyrolyzed, or carbonized, to produce palm kernel shell charcoal (PKSC). The same applies to wood pellets. The only difference is that wood pellet production doesn't involve pyrolysis or carbonization; instead, after drying and achieving the desired particle size, the pellets undergo biomass densification in a pelletizer.

Steel production requires an average of 6,000 MJ of energy per ton (equivalent to 50 kg of hydrogen) or 200 kg of charcoal, and requires approximately 600-800 kg of woody biomass as raw material. With a calorific value nearly identical to woody biomass, this is equivalent to using palm oil mills (PKS), which are plantation or agro-industrial waste.

Meanwhile, demand for low-carbon steel is growing rapidly as steel industries and governments worldwide commit to reducing carbon emissions from fossil fuels. The use of charcoal or biocarbon in blast furnaces is a key component of low-carbon steel production, as 100% of the steel is not yet produced using renewable energy. 

Maximizing Palm Oil Mill Profits with Cogeneration Utilization of EFB (Empty Fruit Bunch) and Export of PKS (Palm Kernel Shells)

As a profit-oriented company, maximizing profits is a natural and ongoing endeavor. Besides increasing efficiency, innovation can also be pursued, creating or developing new businesses. This is especially true if the innovations involved in creating new businesses also address environmental issues, such as utilizing palm oil mill biomass waste. In palm oil mills, empty fruit bunch (EFB) waste is generally underutilized, or if utilized, it is still suboptimal or inadequate, such as composting empty fruit bunches (EFB).

Empty fruit bunches (EFB) are a significant biomass waste product from palm oil mills, accounting for approximately 22% of the total production, but are generally underutilized and pollute the environment. Utilizing EFB through cogeneration will not only address the problem of EFB, but also generate heat or energy to replace the use of palm kernel shells (PKS) as boiler fuel, and also produce high-quality organic potassium ash fertilizer.

If the PKS used for boiler fuel reaches 50%, then using this technology means that 50% of the PKS can be recovered, or 100% of the PKS can be sold or exported. For example, a palm oil mill normally sells 3,000 tons of PKS per month. With this technology, the mill can sell 6,000 tons of PKS per month. This would certainly increase the supply of PKS significantly.

Even if applied on a larger/macro scale, namely in Indonesia with CPO production of around 50 million tons/year, the actual production of PKS is around 12.5 million tons/year. However, with the current practice of utilizing PKS as boiler fuel, say reaching 50% of PKS production, the actual amount of PKS that can be sold/exported by palm oil mills is 6.25 million tons/year. Now, with the use of this technology or the installation of equipment (EFB furnace cogeneration), the amount of PKS that can be sold/exported will be close to or equal to the PKS production in the mass balance or diagram above (not subtracting the amount burned in the palm oil mill boiler).

The demand for palm kernel shells (PKS) is increasing in line with the global decarbonization trend. In fact, PKS is a major competitor for wood pellets in the global biomass fuel market. Large PKS users come from Japan and Europe. PKS exports to Japan typically reach around 10,000 tons per shipment, while those to Europe typically reach a minimum of 30,000 tons per shipment due to the longer distances and the use of handymax or even panamax vessels. Cogeneration of empty fruit bunch (EFB) furnaces with palm oil mill boilers will increase the volume of PKS that can be sold or exported. Implementing this technological innovation, besides being the fastest and most practical, also offers multiple benefits, making it worthy of consideration. It could even become a trend and even a standard operating procedure in Indonesia's approximately 1,000 palm oil mills.

Water Related Problems in Cooling Towers

The constant trickle of water can hollow out rocks. Furthermore, a continuous flow of water will gradually erode everything in its path. A more dramatic and spectacular example is the Grand Canyon in Arizona, United States. Furthermore, if the flowing water is hot, it will erode or dissolve the solids it passes through (leaching) more quickly than cold water. By the time the hot water returns to the cooling tower, it is already full of suspended solids. The cooling tower, as a means of dissipating heat, flows hot water from the top of the tower, and cool air from the surrounding environment that comes into contact with the warm water absorbs the heat. As a result, the water becomes cooler and the air becomes warmer.

Hot water also tends to be corrosive and form deposits. This is why the materials used to construct cooling towers must be durable and able to withstand large temperature differences. Certain types of wood and plastic can be used for cooling tower construction. If the materials are of poor quality, the cooling tower construction will be short-lived and even dangerous. When hot water enters the cooling tower and mixes with suspended solids, some of the water evaporates, leaving the suspended solids behind. This suspended solids-rich liquid concentrates in the sump at the bottom of the cooling tower. Over time, the concentration of these suspended solids increases until it reaches a level that must be controlled by removing it from the system, known as blowdown.

The outside air that comes into contact with the water from the cooling tower contains dust or small particles, as well as microorganisms such as various bacteria, fungal spores, and algae. These dust or small particles become suspended and accumulate/concentrate, forming deposits in the form of mud or crust. In the presence of sunlight, these microorganisms, such as bacteria and algae, photosynthesize, multiplying and increasing in number. Pathogenic bacteria like Legionella can even cause Legionnaires' disease. This mud and algae contaminate and clog heat exchanger tubes, accelerating their corrosion.

In the heat exchanger, if the scale thickness is 0.3 mm, it is estimated that there will be a heat/energy loss of 10% and if the scale thickness is 0.6 mm, it is estimated that there will be a heat/energy loss of 23%. And in general, fouling causes an annual energy/heat loss of around 15%, so it requires maintenance and pipe replacement every 3–5 years. If not handled properly, heat/energy loss due to fouling can reach up to 70% after five years. Fungi and bacteria will cause wood to rot/decompose, making it brittle and destroyed. Likewise, oxidation reactions on metal surfaces, because these metals release electrons or capture oxygen, causing corrosion on the metal. Corrosion on metal causes the metal to become increasingly eroded, brittle and damaged.

Maintaining water quality from various contaminants in a cooling tower, which volume thousands of tons per hour and operates 24 hours a day, is certainly not simple. Only by maintaining this water quality can the cooling tower's performance and lifespan meet its design targets. Using effective, efficient, and environmentally friendly technology is the best option. Advanced Oxidation Process (AOP) technology is an innovation to address these issues. This technological approach effectively, efficiently, and environmentally friendly addresses various water issues in cooling towers. For example, in algae cells, ions from the Advanced Oxidation Process (AOP) attack the sulfide groups contained in amino acids in the remaining proteins involved in photosynthesis. As a result, photosynthesis is inhibited, and the cells dissolve or disintegrate. If algae and microbial cells remain, their regrowth is inhibited by the AOP ions in the water, thus preventing algae growth. During this process, bacteria are also killed or rendered inactive.

The second example is the rust prevention mechanism of pipes. Iron (Fe) loses electrons according to the oxidation reaction and forms rust. However, when the AOP material participates in this reaction and releases electrons first, the iron is prevented from releasing electrons, thus suppressing rust formation. The rusted iron is converted to black rust through the AOP reaction, forming a dense oxide film that prevents further corrosion and protects the pipe and structure.

And the third example is the scale prevention mechanism. When water passes through the AOP system, calcium (Ca) and magnesium (Mg) ions—the components that cause hardness—are removed through crystallization in the liquid phase, thus softening the water. The resulting calcium carbonate particles cannot adhere to pipes. In hard water containing calcium (Ca) and magnesium (Mg) ions, needle-like scale structures typically form and adhere to pipe walls. Through AOP treatment, scale-forming ions undergo particle growth in the liquid phase, forming spherical particles ranging in size from a few micrometers to tens of micrometers.

According to the Gibbs–Kelvin formula, the volumetric free energy is reduced and the adhesive force is lost, thus preventing it from sticking to the pipe walls. Scale will accumulate at the bottom of the basin and be removed by a blowdown mechanism. In addition, this AOP technology will also remove scale that has already stuck to the pipes (scale removal existing pipes) and also the sterilization effect which is also very important for the quality of the cooling tower water such as preventing wood rot/decaying and killing pathogenic bacteria, both of these aspects will be explained on another occasion, Insha Allah.

To measure cooling tower performance based on the problems encountered and the solutions implemented, several parameters are used. These parameters include:
• Water pH
• Total dissolved solids (TDS)
• Tower equipment checklist
• Filters and strainers
• Wet bulb temperature and humidity

Meanwhile, safety in cooling towers is also important and needs to be considered. These include:
• Chemical additives (if used and not yet using AOP technology)
• Rotating equipment
• Dangers of hot water
• Working at heights
• Working safely on the cooling tower.
• Equipment failures
• Metal corrosion and wood rot/decay

The use of cooling towers can be said to be an important and fundamental equipment for industrial operations in general. Starting from power plants that still use fossil energy, cofiring or biomass power plants to geothermal power plants, data centers, chemical industries, biorefinery industries, petrochemical industries, iron and steel industries, food industries, pharmaceutical industries, textile industries, pulp and paper industries and so on. Related to the era of decarbonization and sustainability / sustainability of the use of renewable energy such as biomass including wood pellets and palm kernel shells / PKS as part of carbon neutral fuels or carbon negative such as carbon capture and storage (CCS) to biochar, of course environmentally friendly technology, especially easy to operate, affordable investment costs to repair-maintenance, will be an option for these industries, such as AOP technology for water conditioning in cooling towers so as to provide significant savings.

OPT Briquette and EFB Briquette for Medium Capacity Industrial Biomass Boiler Consumption

The growing utility business, specifically the provision of steam and electricity for renewable energy-based industries, particularly biomass, has led to a growing need for biomass fuel. This also applies to industries using their utility units to produce steam and electricity using biomass fuel. In addition to biomass fuel, water quality, the raw material for steam and electricity production (using steam turbines), is also crucial and must be considered. Good water quality will ensure optimum steam and electricity production performance, and the longevity of equipment (boilers, heat exchangers, steam turbines, and cooling towers), and vice versa. Good water quality is like healthy blood for our bodies, enabling all organs to function optimally.

Palm oil industry solid waste is a potential raw material for biomass fuel. This solid waste is empty fruit bunches (EFB) and oil palm trunks (OPT). EFB is produced from palm oil mill operations with a percentage of approximately 22% of fresh fruit bunches (FFB), while oil palm trunk waste is produced from replanting programs of oil palm plantations, which are also very abundant. For more details, read here. Utilizing both of these biomass wastes for the production of biomass fuel, especially biomass briquettes, would be very good. But why are they processed into briquettes?

The advantage of briquettes over pellets, aside from technical advantages, lies in their scale. Briquette production requires a looser particle size and lower moisture content. Energy consumption per ton of briquette production is also lower than that of pellet production. This makes EFB briquette and OPT briquette production more suitable for a palm oil mill serving medium-sized industries. A palm oil mill with a capacity of 45 tons/hour of FFB will produce approximately 10 tons/hour of EFB. With a 20-hour daily operation, approximately 200 tons will be produced per day. With a moisture content of approximately 60%, this means that after drying, approximately 100 tons/day (10% moisture content) will be produced, or 2,500 tons/month.

Likewise, when using oil palm trunk (OPT) waste as raw material, it depends on the ratio or percentage of land replanted each year. Replanting itself is an effort to continuously maintain the productivity of the oil palm plantation itself, in addition to the use of superior seeds and intensification. For more details, read here. For example, with a land area of ​​10,000 hectares and each year replanting 5% of the land, or 500 hectares. With an average of 125 trees per hectare of oil palm plantation and each tree having an average dry weight of 0.4 tons, then per hectare obtained 50 tons of dry weight of biomass. With an area of ​​500 hectares, this means 25,000 dry palm trunk biomass (10% moisture content) each year or can be processed into OPT briquettes with a capacity of around 2,000 tons/month.

Biomass boilers, used for producing biomass briquettes (EFB briquettes/OPT briquettes), can utilize various combustion technologies, such as moving grates, stokers, reciprocating grates, and so on. The choice depends on the cost or price of the boiler and its efficiency. In addition to biomass fuel, to align with decarbonization and sustainability programs, water for boiler operation, including boiler feedwater and cooling water for heat exchangers (heat exchangers/condensers), is crucial. This is likened to blood for the human body; healthy blood ensures optimal function. If impure blood circulates throughout the body, for example due to kidney failure, organs will automatically be damaged, and a person will soon die.

To maintain water quality for steam production through a boiler, boiler feedwater/demin water must strictly comply with the boiler's operational specifications. The higher the boiler pressure, the higher the water quality or purer the water required. If the steam is used for electricity production, after the steam drives the turbine, it needs to be condensed in a heat exchanger (condenser) so that it changes phase back to liquid and enters the boiler again. This heat exchanger requires cooling water that is continuously used repeatedly, thus requiring a cooling tower. Not only does the boiler feedwater/demin water need to meet the required technical specifications, but so does the cooling water for this condenser. With water volumes circulating up to thousands of tons per hour and operating 24 hours a day (the same as boiler operations) in the cooling tower, a number of water problems in the cooling tower need to be addressed effectively and efficiently. A number of water problems that occur in cooling towers can be read here.

In addition to electricity production, steam is also used for processes within a specific plant. If the steam is then condensed, then liquid, and returned to the boiler, this requires a cooling tower, just as in electricity production. Efficient and environmentally friendly water treatment technology, which eliminates secondary pollution and is easy to operate and maintain, aligns with the vision of decarbonization and sustainability. This vision of decarbonization and sustainability will be even more optimal or ideal for utility units, namely the use of biomass-based renewable energy and environmentally friendly water treatment technology. 

Blue Economy & Bioeconomy – Seaweed, Coconut and Nyamplung

With the second longest coastline in the world, located on the equator so it has a tropical climate and the largest coconut producer in the world, maintaining and continuing to develop coconuts is very important and strategic for Indonesia, especially since Indonesia has long been famous as the land of waving coconut trees. The productive life of coconut trees is also very long, namely 60 years, so they can be passed down across generations. The nyamplung tree, which is easy to grow and is often found in coastal areas, should also be developed, as well as the potential for seaweed. With the development of the times to carry out decarbonization in various sectors of life, especially the use of renewable energy, coconut, nyamplung and seaweed can be an effective solution.

Coconut oil, like palm kernel oil (PKO), has a high lauric acid content, so it is very suitable for the production of Sustainable Aviation Fuel (SAF). Currently, Indonesia is planning to increase SAF production from palm oil, namely palm kernel oil, to 3% this year (2026). This policy was accelerated to support the aviation sector's decarbonization targets. Palm kernel oil production is around 5 million tons/year with the main uses currently being very diverse, including the food industry (margarine, chocolate, cakes), cosmetics (soap, shampoo, lipstick), oleochemicals (fatty acids, glycerol), to renewable energy (SAF) - still in the early stages, as well as non-food products such as lubricants. while the potential for coconut oil is 2.9 million tons with the main uses being cooking (cooking oil), processed food industry (biscuits, margarine, ice cream), cosmetics (soap, shampoo, moisturizer), health (consumed directly as Virgin Coconut Oil (VCO)) and pharmaceuticals (ointment base), skin/hair care and oleochemicals. Why coconut oil and palm kernel oil are very suitable for SAF production, read more details here.

In addition to the potential raw material for SAF from coconut, the international civil aviation organization (ICAO) has included non-standard coconut in the ICAO positive list - ICAO document - CORSIA Default Life Cycle Emissions Values for CORSIA Eligible Fuels, 6th Edition on October 28 20024. Non-standard coconut includes very small old coconuts, already sprouted, starting to rot or become moldy and those that are broken. Based on data from a number of research studies, the number of non-standard coconuts in Indonesia is estimated to reach 30% of Indonesia's coconut production.

Regarding coconuts, the government should limit or prohibit exports of round coconuts. This will not only hinder the domestic coconut processing industry but also more specifically the development of SAF. Apart from that, efforts to replant coconut plantations must also be carried out. The area of ​​coconut plantations that must be replanted currently reaches hundreds of thousands of hectares, such as in Riau alone with a coconut plantation area of ​​426,579 hectares (11.4% of the plantation area in the province, read more details here). 72 thousand hectares of coconuts need to be replanted, while the replanting speed is very low so coconut productivity continues to decline. Meanwhile, nyamplung trees and seaweed require socialization and real action so that they can meet production targets and expectations.

Meanwhile, nyamplung oil can be used for biodiesel / FAME production. From the government's plan to increase the biodiesel mixture from B-40 to B-50, this means requiring almost 60 million tons/year of vegetable oil, especially palm oil. Meanwhile, currently crude palm oil or CPO production is around 50 million tons/year and increasing 20% ​​or to 60 million tons/year is certainly not easy. Moreover, currently the expansion of palm oil plantations (extensification) is in the sharp public spotlight with widespread public attention. A number of natural disasters, especially the Sumatran floods, which have claimed the lives of thousands of people, with the extensification of palm oil plantations as the suspect, have made it increasingly difficult to increase palm oil production through expanding this land. And indeed land expansion (extensification) must always be in the corridor of sustainability, so that palm oil can be a blessing and not a disaster.

Nyamplung trees with productivity almost the same as palm oil trees are very interesting to develop for biodiesel production or more practically adding 10 million tons / year to reach the B-50 proportion. Along Indonesia's very long coastline, there are locations for coconut and nyamplung plantations. Apart from that, seaweed from its waste is also a potential raw material for renewable energy, both ethanol, biodiesel and SAF.

Meanwhile, from the seaweed sector, apart from the production of agar, carrageenan and alginate which are widely used for food products, biofuel can be produced from seaweed waste. Seaweed industry waste can reach 65-75% of the fresh raw materials processed. This very large amount is often wasted without further use which can increase added value. Because solid seaweed waste contains a high percentage of cellulose and only a small amount of lignin, this waste has the potential to be processed into bioethanol and sustainable aviation fuel (SAF). 

The process route, namely ATJ or alcohol to jet fuel, can be used to produce sustainable aviation fuel (SAF). Meanwhile, seaweed waste is usually disposed of in landfills, which can cause unpleasant odor problems. Specifications for industrial waste from the E. cottonii species are 3.66% water content; ash 36.84%; protein 1.78%; carbohydrates 11.36%; 0% cellulose; hemicellulose 12.86%; lignin 0%. Meanwhile, industrial waste specifications from the species Gracilaria sp. and Gelidium sp.: cellulose 26.92%; hemicellulose 16.11%; lignin 15.38%; ash 16.72%; water content 12.94%; NaCl 3.77%. 

After their productive life is over or ends, the coconut trees and nyamplung trees are cut down. Coconut tree trunks and nyamplung trees are very suitable for building wood used for housing. This will add economic value and is a necessity that will continue to be needed. In fact, efforts to improve the quality of wood can also be done by engineering the wood material, such as with CLT (cross laminated timber) and so on.

And like palm oil, both coconut and nyamplung also produce shells. Just as palm kernel shells can be used for fuel, so coconut shells and nyamplung shells as well. Even palm kernel shells or known as PKS (palm kernel shell) are the main competitors of wood pellets in the global biomass fuel market. However, because the quality of coconut shells is better or more suitable for the production of charcoal briquettes and activated carbon, coconut shells are generally carbonized or made into charcoal. Charcoal is an intermediate product or raw material for charcoal briquettes and activated carbon. Read more details about the production of activated carbon from coconut shells here. Meanwhile, because nyamplung shells are not widely produced, their use is still limited, but if the quantities are large, such as the production of palm kernel shells, then it could be like palm kernel shells, or perhaps also like the use of coconut shells.

Apart from that, both the production and extraction of coconut oil and nyamplung oil will produce cake. Coconut cake and palm oil cake can be used as animal feed, but nyamplung cake requires additional processing so that it is non-toxic and safe for animal feed. The development of a blue economy on the Indonesian sea coast should be an important concern as an environmentally friendly economic solution that suits the conditions and potential of Indonesian society and is in line with the global community's concerns about decarbonization as mitigation for climate change and global warming. Apart from also supporting food and feed security.