Biomass Boiler and Its Urgency

A problem that is visible and can be felt, especially if it has a short-term impact, is certainly easy to map and find a solution to. But if the opposite namely is not visible, it is difficult to feel and the impact or effect is long-term, of course it is more difficult to map, let alone find a solution. The use of fossil fuels, especially coal in a number of industrial boilers, is an example. The effects of exhaust emissions in the form of COx, NOx and SOx may be difficult to detect at first but create environmental damage in the long term. Likewise heavy metals like mercury which also have long-term effects. Meanwhile, fly ash pollution and boiler furnace ash (bottom ash) are clearly affected more easily. In a larger case or global scale, namely climate change and global warming due to greenhouse gases, especially CO2 (carbon dicside), a global consensus is also needed to solve these problems. That is what makes the Earth Conference on Climate Change (UNFCC) always held every year, which has so far been recorded 27 times, lastly in 2019 in Madrid, Spain, while what was supposed to be held in 2020 was postponed in 2021 due to the COVID-19 pandemic. Fossil fuels including coal are carbon positive fuels so that their use will increase the concentration of CO2 in the atmosphere, while biomass fuels such as wood chips, wood pellets, wood briquette and palm kernel shells (PKS) are carbon neutral fuels. It is said to be carbon neutral because of the use of this fuel because it does not increase the concentration of CO2 in the atmosphere.

 

Boilers are essential equipment for the operation of a number of industries. The main function of the boiler is to produce steam which is used in the industrial production process. But when the boiler is not operated and maintained properly, the boiler can be dangerous. The continuity of production operations also greatly depends on this equipment, so that disruption of boiler operations will have a significant effect on this production. The boiler also consists of a number of subsystems that work in harmony, such as boiler burners and controls, water treatment for boiler feed water preparation, fuel handling and feeding and so on. Sometimes a number of subsystems are supplied from a number of different vendors, so synchronization between these subsystems is very important. This makes boiler operations safe, efficient, reliable and minimizes boiler downtime. And of all the subsystems in the boiler, the burner system is the most sophisticated subsystem in the boiler unit. The burner system has a number of operational modes that require extensive training and / or experience for boiler operators to be well understood.

Currently, a number of industries have started to switch from fossil fuels to biomass fuels. In industries that previously used solid fuels, technical changes or furnace modifications can be minor, while in industries that previously used gas or liquid fuels, the usual thing to do is replace the boiler unit (including the furnace). Of course, the replacement of the boiler unit is also followed by its supporting systems such as fuel storage, provisioning and so on. Petroleum fuels, coal and natural gas are consistent fuels with standard quality and their contaminants or impurities have been known and studied for decades. Whereas with biomass there are a number of options and each source is also unique and also the level of contaminants.

In certain cases, industries that will switch to using biomass, namely palm kernel shells (PKS), that previously using natural gas, so the industry needs to study and analyze the implications of using the PKS. And because the use of PKS for industrial fuel is relatively new, the industry can use old data about their furncae operations with natural gas and compare it to furnace that use solid fuels like coal - which is commonly used by the industry today. Although PKS is also a solid fuel, there are a number of characteristics that distinguish it from coal. In addition, gas combustion can be said to be the most ideal combustion process, which is in terms of stoichiometry or the perfection of combustion compared to combustion of liquid or solid fuels. Large particle size such as coal will also have an effect on combustion and also make a fuel more difficult to burn. So that from this comparison, the industry can get an overview of the burning of the PKS and the scheme below to describe the case.

With adequate analysis, planning and system design, the use of new fuels, especially biomass, such as wood chips, wood pellets, wood briquettes and PKS can be implemented properly. Energy prices and environmental regulations are driving forces for the use of this new fuel. Fixed bed combustion type furnaces are most commonly used in a number of industries. These furnace variants include grate furnace types namely traveling grate, fixed grate system, incline moving grate & horizontally moving grate, vibrating grate, cigar burner and underfeed rotating grate, while other types are underfeed stokers. Meanwhile, the fluidized bed and pulverized combustion types are generally used by power plants. The technical considerations for selecting biomass-based solid fuels include heating value, moisture content, ash content, density, particle size, emissions, availability of these fuels, and suitability for the furnace. In the end, the most optimal combustion rate that is safe and meets environmental standards is the purpose of using the biomass fuel.