An asphalt mixing plant (hereinafter referred to as the mixing plant) used by a certain unit uses diesel as fuel in its production. As the price of diesel in the market continues to rise, the operating cost of this equipment is getting higher and higher, and the benefits are constantly decreasing. In order to reduce production costs, it was decided to use a low-cost, good combustion performance and meet the requirements of special combustion oil (heavy oil for short) instead of diesel as fuel.
Failure phenomenon
In the process of using heavy oil, the asphalt mixing equipment burns with black smoke, the recovered mineral powder turns black, the combustion flame becomes dark, and the hot aggregate is odorous, and the fuel oil consumption is large (7kg heavy oil is required to produce 1t finished material) . After producing 3000t of finished material, the imported high-pressure fuel pump was damaged.
After disassembling the fuel high-pressure pump, it was found that its copper sleeve and screw were seriously damaged. Through the analysis of the structure and material of the pump, it is known that the copper sleeve and screw used in the pump are not suitable for burning heavy oil. After replacing the imported high-pressure fuel pump with a domestic high-pressure fuel pump, the phenomenon of burning black smoke still exists.
Analysis believes that the burning smoke is due to insufficient combustion using mechanical burners. There are three main reasons: one is the uneven mixing of air and oil, the other is poor fuel atomization, and the third is that the flame is too long. Insufficient combustion will not only cause the generated residue to stick to the gap of the dust collector bag, hinder the separation of dust from the flue gas, but also make it difficult for the dust to fall off the bag, which affects the dust removal effect. In addition, the sulfur dioxide produced during the combustion process will also cause serious corrosion to the bag. In order to solve the problem of incomplete combustion of heavy oil, we take the following improvement measures. 2. Improvement measures
(1) Control oil viscosity
When the viscosity of heavy oil increases, the oil particles are not easy to disperse into fine droplets, which will cause poor atomization, which will lead to burning and black smoke. Therefore, the viscosity of the oil must be controlled.
(2) Increase the injection pressure of the burner
The function of the burner is to atomize the heavy oil into finer particles, and spray them into the drum to mix with air to form a good combustible mixture. Therefore, we increased the injection pressure of the burner, effectively improved the quality of the combustible mixture, and improved the fuel conditions.
(3) Adjust the ratio of wind and oil
Adjusting the ratio of wind and oil properly can make fuel and air form a good mixture, avoiding incomplete combustion and causing black smoke and increasing fuel consumption.
(4) Add fuel filter device
Replace with a new fuel high-pressure pump, keep the original circuits, pressure gauges, safety valves and other components in place, and install multi-stage filtering devices on some fuel pipelines to reduce impurities in heavy oil and ensure full combustion.
