Technical analysis of dust removal in cement plantDate: 2019-06-16 Views:
Most of the electric precipitators used in the early construction of cement plants are electric precipitators are currently facing the phenomenon of excessive emission caused by technical problems or aging of equipment.
Therefore, kiln head, kiln tail waste gas treatment system reform bag dust collector is imperative.
In the years before the implementation of the new regulations, each cement plant is mainly for the end of the kiln to carry out electric bag work, but with the implementation of the new regulations, the kiln head electric dust collector energy conservation work has become urgent.
The main source of flue gas in the kiln head is grate cooler, and the temperature of the flue gas after the grate cooler is usually between 200℃ and 250℃. Due to the influence of many factors, such as the amount of air used by the grate cooler and the condition of the kiln, the unexpected situation will reach 450℃.
The original electric dust collector can withstand this temperature, but for the ordinary high temperature filter material used by the modified bag dust collector, this temperature cannot be borne, so it is necessary to cool the flue gas entering the bag dust collector.
There are three main cooling measures:
(1) air cooler cooling.
(2) spray constant temperature control for cooling (spray water for cooling).
(3) cooling air.
According to the transformation examples and experience in recent years, the three cooling measures are compared (take 2 500t/d cement production line as an example).
For different cooling methods, the transformation sequence of kiln head is also different. The general transformation process is described as follows:
1. Adopt air cooler cooling scheme
The cooling system of air cooler needs to change the technological process. There is 1 air cooler in series between the outlet of grate cooler and the entrance of bag dust collector.
The reconstruction sequence is the civil construction of the forward air cooler in the stopped kiln, and the production of air cooler and series non-standard pipeline. After the completion of the civil construction, the installation of air cooler and the installation of the stair platform is started.
The air cooler is prepared to complete the installation of non-standard pipes in series after the system stops the kiln. The non-standard pipes here need to be calculated and designed according to the direction of the original kiln head process pipes in each cement factory, so as to achieve reasonable layout and fast installation.
2. Spray constant temperature control scheme is adopted
This kind of scheme has the advantages of short transformation time and low input cost. The water spray valve group and spray gun are grouped in the factory and sent directly to the site for installation.
It is recommended to use it as a cooling measure when there is surplus heat in the system.The civil construction, manufacture and installation of air cooler and non-standard pipeline are reduced.
3. Adopt the cooling air scheme
This kind of scheme only adds cold air valve and actuator on the process pipeline, which needs to ensure that the position of cold air valve installed has enough negative pressure, and the transformation time and investment cost are relatively low. However, due to the strict requirements on the design margin of dust collector, it is not recommended to use at present.