Bypass ventilation operation in cement plant
Date：2019-08-21 15:27 Source：cementepcViews:
Bypass technology emerged in the 1980 s, initially mainly aiming at high alkali content in raw materials developed by the technical countermeasures, with the use of cement production process to waste disposal and comprehensive utilization of resources, many products that contain a large number of the composition such as chlorine, sulfur waste as cement production of the original fuel into the clinker burning link.In order to solve the influence of chlorine or sulfur brought in by waste on the firing process, a bypass chlorine removal technology was developed.Because this technology effectively suppressed the influence of high concentration of chlorine ion, the clinker firing process realized stable operation, and also made the waste with high concentration of chlorine (especially waste plastics) greatly increased in the cement plant production process.
At present, China's cement industry and environmental policy regulation transformation and upgrading, 'collaborative disposal' related technology and equipment also received the previous attention.However, in terms of bypass chlorine removal technology, there is still a significant gap in terms of engineering design, equipment and other hardware, as well as the basic indicators to measure bypass technology, from the comparison of several operating conditions of relevant manufacturers in China.Especially, there is still a big gap in the quantity of high concentration chlorine powder extracted by bypass, environmental protection factors and other aspects. Meanwhile, the operation cost is too high and the treatment of chlorine ash extracted is also facing problems.
1. Why is a bypass chlorine removal system needed
Chloride ion component is the main harmful component in the process of Collaborative disposal of cement kilns.Its active volatilization has a great negative effect on the firing process of clinker which cannot be controlled or eliminated only by the usual technological means.
To eliminate the influence of chlorine, the concentrated chlorine component must be exported out of the firing system.The bypass chlorine removal system is the technical means to solve this problem.Through this technology, the chlorine components in the end area of kiln can be exported out of the firing system, so as to reduce or eliminate the influence of chlorine.
2. How to select the effective and cost-effective bypass chlorine removal system
A set of criteria and criteria for the selection of energy efficient bypass techniques.Better bypass equipment can be selected by referring to its standard.
1) it can efficiently export chlorine ion components from kiln and preheater system, and reduce the concentration of chlorine ion in the cycle of sintering system (chloride ion extraction rate: ≈90%).
2) can effectively separate high-concentration and low-concentration chlorine-containing powder, so that low-concentration powder can return to the sintering system as much as possible, reducing energy loss.
3) the concentration of chlorine ion in by-pass chlorine ash should be above 20% in general.
4) the yield of by-pass ash is less than 0.2% of the clinker yield.
5) good energy saving.
6) small size, good handling;Long service life, simple maintenance.
3. Main technical features of bypass chlorine removal system
It is composed of several most core equipment, its main technical characteristics can be summarized as follows.
1) efficient and miniaturized suction probe for kiln end (high-chlorine hot air extraction equipment for kiln end)
The pump probe is the most important and key equipment to determine the performance and efficiency of bypass chlorine removal system.
2) reduce the emissions of by-pass chlorine ash through precise cyclone separation technology
The bypass chlorine removal system is equipped with specially designed cyclone tube, which can separate the bypass powder particles with high chlorine content from those with low chlorine content by means of cyclone separation.Finally, the powder derived from the sintering system is only the part with high concentration of chloride ion, and its proportion is very low.This will create favorable conditions for the next treatment of by-pass chlorine ash and reduce the pressure of by-pass chlorine ash.
3) efficient gas cooler
When using the by-pass chlorine removal system, in order to ensure that the dust collector in the back section of the system is in a safe operating temperature range, cold air should be imported from the outside to cool down.This not only causes an increase in the exhaust air volume of the bypass system, but also may lead to an increase in SOx concentration in the exhaust of the bypass system according to different operating states of the sintering system.To solve this problem, an efficient indirect gas cooler is installed in the by-pass chlorine removal system of the cement plant.The effect of the cooler reduces the amount of cooling air entering the bypass system.Not only is the bypass volume reduced and the dust collector capacity reduced, but the pressure and impact of dealing with SOx gas is reduced.This is one of the important factors to improve and optimize the performance and efficiency of bypass chlorine removal system.
Not only can the quantity of chlorine-containing waste be significantly increased, but also the operating condition of cement kiln system can be effectively improved.If you have any more questions about cement plants, please contact us. We will reply to you as soon as possible.