Design and maintenance of dust removal system in cement plantDate: 2019-08-22 Views:
Dust removal system of cement plant, including dust collector, fan, pipe network and process equipment.In the design and maintenance of dust removal system, attention is often paid to the dust remover and fan itself, while the problems in the pipeline system are often not thoroughly analyzed and solved, which leads to the poor operation status of many dust removal systems, or even not normal operation, or even scrapped.
1. The design and maintenance of pipelines in the dust removal system will affect almost every factor in the efficient operation of the dust removal system, namely:
(1) deal with air volume and wind pressure;
(2) dust concentration;
(3) gas temperature, humidity and dew point;
(4) specific resistance of dust;Dust removal efficiency.
In some cases, also directly affect the normal work of the process equipment
2. At present, the dust removal problems of cement plant due to pipe network factors are generally not caused by the pipe network does not conform to its layout principles, but the main problems are:
(1) the dust gas to be treated cannot enter the pipe network efficiently;
(2) serious air leakage in pipe network.
To this end, we will cement plant on the process of dust collection system, classification demonstration to illustrate the importance of dealing with the above problems.
3. Dust removal system of crusher
In the material crushing system, in addition to the crushing and drying system, the main characteristics of dust gas are: no temperature difference, no condensation, high dust dispersion.The key problem in pipe network design is whether dust gas can enter pipe network efficiently.
At present, cement factory commonly used crushing equipment mainly jaw, cone, hammer, impact crusher.Among them, the first two kinds of crusher generally low speed.It mainly crushes materials by means of extrusion. The amount of dusting gas produced by the action itself is small, and its flow rate is also small, so the dusting range is not large, and the dust collection problem is easy to solve.
There are mainly the following solutions in the design:
A single-plate choke valve is set in the discharge chute to reduce the amount of gas discharged (1/4 ~ l/3 can be reduced), and a closed cover is set at the same time. In this way, not only the amount of exhaust air can be reduced, but also the dust gas can be effectively entered into the dust removal equipment, and the dust removal effect can be significantly improved.
4. The dust collecting system of a dust collector is Shared by multiple dust spots in the feeding and transportation equipment
Cement plant feeding, transport equipment in a number of dust dust removal system examples, raw materials, cement grinding head (or warehouse bottom) electronic belt scale (or bucket scale) batching system, materials (granular or powdery out, storage system, dust collection.The characteristics of dust gas in this kind of dust spot are as follows: small gas volume (generally induced air volume due to material drop), no temperature difference, and high dust dispersion.The key problem in the design and maintenance of this kind of dust collecting pipe network is whether the dust gas can enter the pipe network efficiently.According to the above characteristics, the design must achieve the following points.
(1) the unloading drop of equipment should be as small as possible.
The equipment discharge drop difference is small, not only induces the air volume is small, but also the gas dust concentration is small, thus reduces the dust removal system load, creates a good prerequisite for dust removal.
(2) each dust spot shall be equipped with dust hood with high dust collection efficiency and good airtightness.
In order to make the vacuum hood suction dust gas with high efficiency and good airtight performance, the key is to make the vacuum hood and feed, transportation equipment between the body of the gap as small as possible, can be connected into a whole.In the impact of the maintenance of the equipment, take easy to remove, easy to install bolts and sealing gasket connection.
(3) according to the air volume required by each dust spot, balance the gas pressure in the pipe network node
Pressure balance is an important issue that must be considered in the design of nodes (generally refers to the three or four connections in parallel pipelines), otherwise, the air volume to be extracted from each dust spot cannot be guaranteed.After equilibrium, the difference of resistance between 2 tubes should be less than 5%.Otherwise, quadratic equilibrium calculations are required.In addition, in the design fashion needs to set up the adjustment valve, facilitates in the actual use to adjust.
In addition to the design according to the above pipe design principle, when more than 5 ~ 6 dust collecting points are connected, the collector pipe can be used.It is suitable for the concentrated dust source in different layers or two adjacent layers.
5. Rotary kiln system
The main air leakage parts of rotary kiln system are kiln head, kiln tail and preheating system.These parts belong to the piping system in kiln.Air leakage in these parts not only affects dust removal, but also increases the heat consumption of clinker, which is one of the main reasons for the large gap between China's clinker heat consumption and the world's advanced level.
Air leakage in the kiln head reduces the cooling air volume of clinker, and the temperature of the secondary air in the kiln decreases while affecting the quality of clinker. At this time, the method of increasing the amount of coal used in the kiln can meet the requirements of calcining temperature in the kiln.Similarly, air leakage in the kiln tail and preheating system also reduces the temperature of gas in the preheating system. In order to meet the requirements of preheating materials, it must be solved by adding fuel.In this way, is finally leading to a preheater exhaust volume increase.At this point, if the waste gas temperature is high, the clinker heat consumption is greater.Transport a large number of excess exhaust gas, exhaust fan power consumption increment is also very considerable.Due to the great negative pressure of gas in the pipeline system before the exhaust fan or the preheater, if there is an opening in the pipeline (or if the air is not tightly sealed), the air leakage is very surprising (at the site opening, stones with big fists can be sucked into the pipeline by gas), please pay attention to close and seal in production.
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