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. 

Strengthening Sustainability Efforts by Reducing or Eliminating the Use of Chemicals in Palm Oil Mill Boiler Feedwater Treatment

A lot of palm oil companies now have sustainability certificates, such as ISPO (Indonesian Sustainable Palm Oil) and RSPO (Roundtable on Sustainable Palm Oil). To market palm oil and its derivatives to Europe, the European Union has implemented the EUDR, or European Union Anti-Deforestation Regulation. This regulation requires every business actor to prove that their palm oil does not originate from deforested land after the deadline of December 31, 2020. The EUDR itself will be implemented on December 30, 2026, for large and medium-sized companies. Sustainability certifications such as ISPO and RSPO are not the same as EUDR compliance, but they complement each other. This is because ISPO or RSPO serve as important tools to strengthen traceability and due diligence to comply with the EU's anti-deforestation regulations. Once certified, ISPO or RSPO simply add detailed spatial geolocation data to fully comply with the EUDR standard.

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 an option, and even an obligation. Sooner or later, these climate-smart efforts will become increasingly accepted and become an integral part of human life. For example, the palm oil industry is currently moving towards the use of 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 and ISPO. The use of electric vehicles allows palm oil companies to claim reduced fossil fuel use and reap sustainability benefits.

Another example is the use of organic fertilizers or biofertilizers. The use of biofertilizers or organic fertilizers can have several positive effects on environmental sustainability, as they can reduce the use of chemical fertilizers by up to 25%. This effort not only reduces environmental pollution and health risks but also enriches biodiversity and supports climate-smart agriculture. In an era where sustainability is a focus and a "selling point" for products (especially in Europe), this effort is very effective. This is especially true given the intense competition from other vegetable oils, such as soybean oil and sunflower seed oil.

This is also closely aligned with water treatment, particularly boiler feedwater treatment, which uses less or no chemicals. This also reduces environmental pollution and health risks. Boilers can be considered the "heart" of palm oil mills, converting water into high-pressure steam to power 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 is not only uneconomical due to high maintenance and operational costs but also dangerous. Good and well-maintained water quality will ensure the boiler's lifespan meets or even exceeds standards.

The average lifespan, which is the technical and economic life of a palm oil mill boiler, is 20 years, and by maintaining water quality, it is expected to be 20% longer, to 24 years. In addition to the technical and environmental benefits, there are also economic benefits. A palm oil mill with a capacity of 45 tons of fresh fruit bunches (FFB) per hour using electrochemical technology will achieve an estimated annual savings of over 250 million rupiah. For more detailed information, please contact us. Currently, according to data from the Indonesian Ministry of Agriculture, the number of palm oil mills in Indonesia is recorded at around 1,200 to 1,500. This is understandable, considering the increasing area of ​​oil palm plantations, currently reaching nearly 17 million hectares, thus increasing the need for palm oil mills.

Why make calculations or simulations for a palm oil mill with a capacity of 45 tons of fresh fruit bunches (FFB)/hour? This is because this capacity is the average capacity of palm oil mills in Indonesia. For example, one of the largest palm oil companies, PT Astra Agro Lestari (AALI), has 32 palm oil mills with a total capacity of 1,570 tons of fresh fruit bunches (FFB) /hour, or an average of 49 tons of FFB /hour, which is close to a capacity of 45 tons of FFB /hour. And with the number of mills in Indonesia, say 1,500 units and each mill can save 250 million rupiah/year, there will be an estimated savings of 375 billion rupiah per year from this boiler feed water treatment, in addition to technical and environmental benefits, especially to strengthen sustainability efforts to meet EUDR requirements.

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.