With the improvement of national environmental protection standards, natural gas is called clean energy because of its high calorific value and low sulfur content, and it is adopted by more and more float glass manufacturers. The natural gas fuel contains very little sulfur, and Na2SO4 is used as the clarifying agent of the glass to decompose to produce a trace amount of SO2. For the kiln that uses natural gas as fuel, by adopting technological measures to adjust, the SO2 emission concentration can be controlled below 400 mg/Nm3, and its emission concentration can meet environmental protection requirements.
Take the two float glass production lines of a float glass company in Chengdu as an example. It uses natural gas as the fuel for melting glass and has a waste heat generator set with a capacity of 6 MW. The waste heat of the flue gas is used for power generation and electrostatic dust removal. And SCR denitrification technology for flue gas dust removal and denitrification. Since the denitrification system operates continuously every day, the amount of dust collected by the electrostatic precipitator is large, and when the denitrification system is operating normally, it can basically collect about 400 kg of dust per day. Due to the large quantity and low density of the collected dust, it is easy to agglomerate after encountering water, and is corrosive to a certain extent, which is likely to cause new pollution to the water and soil and cannot be dumped into the garbage dump as ordinary garbage. The dust is bulky and covers a large area, which brings great difficulty to its storage and disposal. In order to find out whether the collected dust can be used as raw materials in the production line, a lot of research work has been carried out on it.
First, in terms of chemical composition and particle size, samples were taken from the dust collected by the electrostatic precipitators of the two float line denitration systems, and chemical composition analysis was performed. similar.
Secondly, conduct a dissolution test on the sample. Put the flue gas dust sample and the Glauber's salt sample into a beaker, add water and heat and stir to dissolve them. After dissolution, the Glauber's salt sample is completely soluble in water and the liquid is clear; the flue gas dust sample is also Dissolved in water, the liquid is slightly yellow, slightly turbid, and a small amount of particulate matter can be seen at the bottom of the cup. The pH value of the sample liquid was measured, the pH of Glauber's salt was 8.43, and the pH of the flue gas dust sample was 7.00.
Through the above test, it can be seen that the main chemical component of the flue gas dust collected by the electrostatic precipitator of the flue gas dust removal and denitration system is Na2SO4 (sodium sulfate), its purity is 1.6% to 3.7% lower than that of Glauber's salt, and the flue gas dust contains about 3% The other substances in the glass furnace should be caused by the water-insoluble batch material in the glass furnace entering the flue with the flue gas and depositing in the electrostatic precipitator.
Since the electrostatic precipitator powder is collected by the flue gas in the electrostatic precipitator through the flue system, the entire system is in a relatively closed state. During the normal operation of the kiln, no other substances will be brought into it. Through analysis, the electrostatic precipitator powder should be able to As a raw material to replace part of Glauber's salt and reduce the amount of Glauber's salt in the batch, it will not have a greater impact on the quality of the glass after use.
In the use of dust removal powder, the following matters should be paid attention to:
(1) Stable drawing capacity, stable fuel consumption, stable kiln atmosphere, stable flue gas volume, ensure the stability of the denitration process, and keep the state of dust collected during the denitration process stable
(2) Analyze the chemical composition of the collected dust in a timely and accurate manner, adjust the material side in time, stabilize the glass composition, form a stable glass melting system, and ensure the stability of production;
(3) In the batching process, it is found that adding or releasing If the material is not smooth, check and deal with it in time to maintain the normal operation of the batching system.
