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. 

Optimizing Cooling Tower Performance by Improving Water Quality with Environmentally Friendly AOP Technology

Cooling towers are important and vital equipments for the operations of various processing industries at large. This cooling process is very important for the processing industry, chemical industry, oil and gas industry (oil refineries and petrochemicals), biofuel and biorefinery industries, power plants (fossil fuel and biomass), geothermal and large-scale (hyperscale) data centers. With the process conditions achieved, the industry can produce products that are economical/efficient and stable.

The cooling medium in the industry or factory is water, and the water is cooled in a cooling tower. And air from the atmosphere is used to cool warm water from industrial or factory processes through this cooling tower. This results in direct contact between air from the atmosphere and the warm water to be cooled. This is a source of pollution for the cooling tower water. A certain amount of additional water (make-up water) also needs to be added to replace lost water such as blow down, leaks and so on.

With continuous 24-hour operation for almost a whole year with a large volume of circulating cooling water, up to thousands of tonnes/hour, it is certainly not a simple matter to be able to maintain good and stable water quality. If water quality cannot be maintained, a number of serious problems will arise. A number of problems for cooling tower operations such as corrosion, scale, layers formed by green algae, organic materials and a number of micro organisms will reduce the performance of the cooling tower. If this happens, heat exchange will be disrupted and energy requirements for cooling tower operations will increase. When the cooling process does not work as it should, it will also affect product quality and the durability of production equipment, in the extreme case, if the cooling tower does not function, the industry or factory will stop operating (shut down).

If the cooling tower is damaged or has low efficiency, such as due to scale, there will be a low heat dissipation effect and a lot of energy loss. Then rust causes the pipe to become brittle and leak, resulting in a short life span for the pipe. Then the appearance of green algae, moss and mud from the accumulation of organic material, these things will disrupt the flow of water and even block pipes and valves. Another nuisance is the presence of bacteria and especially legionella (pathogenic bacteria that cause legionellosis) which causes various health problems.

Cold water as the output/product of the cooling tower will be used as a cooling medium in industry or factories such as condensers or other heat exchangers. The layer of fouling formed by scale on the surface of the heat exchanger ultimately reduces the overall heat transfer coefficient. In general, about 15% of energy is lost each year due to a decrease in heat transfer efficiency caused by fouling. Therefore, it is necessary to replace the pipes periodically every 3 to 5 years, and that is not a cheap cost. Even if the fouling problem is not controlled, heat loss can reach up to 70% after five years of operation.

If a problem occurs, repairs need to be carried out and often cooling tower repairs are expensive. A number of improvements/repairs to the cooling tower include structural repairs, replacement of mechanical components, drift eliminators, water distribution and fill types. Apart from the design problems of the cooling tower equipment manufacturers, water quality problems greatly affect the performance and lifespan of the equipment. This means that one solution is that efforts to maintain water quality must be maximized.

AOP (advanced oxidation process) technology has become the focus of developed countries to maximize water quality, including water as a cooling medium that is processed in cooling towers. AOP technology provides complete sterilization without leaving toxic residues and exhibits much stronger oxidizing power than conventional oxidants such as chlorine, chlorine dioxide and potassium permanganate. AOP technology specifically designed for reaction speed and intensity will be very effective for this purpose.

Compared to chemical treatment, although chemical treatment is still commonly used, there are restrictions due to environmental pollution and formaldehyde production, as well as because workers are exposed to serious dangers. As the restrictions on environmental pollution by respective governments become increasingly stringent, the use of chemicals will become increasingly restricted. Several developed countries are starting to control the addition of chemicals. The Singapore government has banned the addition of chemicals to cooling towers since 2008.

If you are interested in knowing AOP technology and its application for cooling tower water conditioners, please contact: eko.sbs@gmail.com