The question of why biomass pellet cokes is a common problem encountered by many biomass pellet fuel plants and customers who use biomass pellet fuel. , so whose problem is it, please listen to our opinions.
First, let's take a look at what the coking of biomass pellets looks like, and what does it look like without coking.
The picture above is the ash from the biomass burner. This is a normal ash situation. the ash is loose and sandy, which is easier to clean.
The picture above is the unburned biomass pellet fuel ash, some of the pellets are carbon-like, and some are tar.
Through the comparison of the above two pictures, we will analyze the cause of coking in detail, why the same biomass particles are burned, and different results in different equipment?
As we all know, biomass fuel is generally processed from rice husks, straws, sawdust, bark, peanut shells and other plants. Since the raw materials themselves contain high potassium, sodium, silicon and other elements, the ash melting point is low, and when burned in the burner, The working condition is that the ash in the fuel begins to soften slowly into a hemispherical shape at 500 degrees, and becomes a complete flow state at about 600 degrees. For particles of any kind of material, almost all particles will undergo fluid ash melting when the temperature is above 1300 °C. After the ash melts, it presents a flowing glass state, and after cooling, it becomes a hard glass state, which is the coke we see. Therefore, the same particle may have different degrees of coking under different working conditions. There are almost no particles that are not coked, but the degree of coking of the particles is different. Through the above introduction, we know that coking is related to the melting point of ash, in fact, it is also related to the working conditions of the burner and the operation of the workers. The following is a specific analysis.
The first reason of coking is that the biomass pellet fuel is mixed with too much ash in the process of processing, which leads to coking.
In the production process of biomass pellet fuel, various magazines such as soil and fine sand are inevitably mixed into the raw material. The existence of these impurities changes the ash melting point of biomass pellet fuel and aggravates the coking on the heating surface. The main factors affecting the melting point of ash are the chemical composition of ash and the surrounding high-temperature environmental medium. The two influence each other. Once the burner combustion adjustment is not in place, incomplete combustion products will appear, making the surrounding medium weak reducing , reducing the ash fusion and causing coking in the furnace.
The second reason for coking is that the improper operation of workers causes unstable combustion conditions of biomass burners and biomass pellet fuel, and insufficient combustion causes coking.
The biomass pellet fuel sub-boiler cannot be fully burned, mainly because the fuel feed volume and air distribution cannot be perfectly matched, and the air volume of the blower is unevenly distributed in the furnace of the combustion equipment, resulting in insufficient combustion of fuel in some areas, resulting in local high temperature , Impervious combustion is also the cause of coking in the furnace. Reducing the blast air pressure and installing or strengthening the boiler exhaust will also reduce the degree of coking. Therefore, it is very important to choose a suitable air distribution ratio.
The third reason of coking is the burning of peanut husk particles, palm husk particles, rice husk particles, and straw particles, which have a large ash content or contain oil, resulting in coking.
As mentioned above, coking has a certain relationship with the ash melting point. Fuels such as peanut husk particles, rice husk particles, and straw particles must burn and coke, which is caused by excessive ash melting point.
The fourth reason of coking is the problem of combustion equipment, coking caused by improper design of combustion equipment
At present, the biomass pellet combustion equipment in the market is chaotic. Many small workshops do not have their own R&D technology. Our company's biomass pellet burners have a professional R&D team that constantly improves and upgrades according to customer usage and customer needs, while ordinary biomass pellet burners disrupt the market with low prices, causing a lot of customers are being fooled.
The above is the company's opinion on the coking of biomass pellet fuel. Customers should eliminate the misunderstanding of coking, do not blindly take it for granted, but analyze why coking occurs according to the actual situation.
