1. Rotary kiln incinerator
Rotary kiln is the most widely used furnace type in movable hearth. Furnace type technology is mature, simple and flexible, and is widely used for incineration of all kinds of solid, semi-solid and liquid wastes, especially for incineration of medical wastes and hazardous wastes with high water content and difficult treatment. It has the characteristics of large capacity, small floor space, high elimination rate of harmful components, simple equipment and long-term continuous operation, and has been widely used in various countries.
The rotary kiln body is a horizontal and rotatable cylindrical cylinder. The shell is made of coil and lined with refractory material; The axis of the cylinder keeps a certain inclination angle with the horizontal plane, and the solid viscous waste moves slowly from the kiln head (upper part) to the tail with the rotation of the kiln body, and the rotation of the kiln body makes the materials fully contact with the combustion-supporting air during the combustion process, thus completing the whole process of drying, burning and burnout. Finally, the burnt slag is discharged from the tail. The incompletely decomposed materials will enter the secondary combustion chamber for full combustion. Combustion air is taken from the silo to ensure that the smell of the silo will not leak. The shell of kiln body is made of carbon structural steel plate by rolling and welding. The refractory material in the kiln is acid-resistant refractory clay brick.
The secondary combustion chamber is a cylindrical cylinder vertical to the ground, and its main function is to further decompose unburned harmful substances in the rotary kiln at high temperature, and at the same time, it can also spray some liquid wastes into incineration. In order to thoroughly decompose unburned substances, a secondary air inlet device and a producer gas nozzle are installed in the secondary combustion chamber to ensure that the flue gas can fully contact with oxygen at high temperature and the residence time of the flue gas in the secondary combustion chamber. The air intake of the secondary combustion chamber can be automatically adjusted according to the oxygen content of the flue gas at its outlet. The secondary combustion chamber is of refractory brick structure, with high alumina refractory layer inside, perlite and aluminum silicate fiber felt as insulation layer, and heat-resistant steel plate outside. In order to ensure the safety of the system, an emergency discharge safety valve is set at the top of the secondary combustion chamber. The emergency discharge safety valve can be automatically opened according to the preset opening conditions.
2. Fixed grate incinerator
Grate incinerator is a kind of grate incinerator and the simplest incinerator. The shell of the furnace body is welded with steel plates, the incineration chamber is built with refractory materials or prefabricated refractory materials, and thermal insulation materials are filled between the refractory bricks and the steel shell. The lower part of the incinerator is provided with a fixed grate, and the feed inlet can be arranged at the upper part, front part or side of the incinerator.
The garbage to be treated is manually put into the furnace, leveled and spread evenly on the grate. The lower part of the grate is a ash pit, which is used as a ventilation room, and the combustion-supporting air is sent in by natural ventilation at the ash outlet or forced ventilation by the fan. In order to burn the garbage completely, it is necessary to turn over the material layer during the incineration process, and the burnt ash falls into the ash pit under the grate and is pulled out manually. The combustion-supporting device is installed on the side wall of the incinerator, so as to be used when the incinerator is started and stopped and the calorific value of garbage is low. The temperature in the incinerator is generally controlled at about 700℃-800℃, and the burnt flue gas and unburned combustible materials enter the secondary combustion chamber for complete combustion, and the temperature in the secondary combustion chamber is generally controlled at about 900℃- 1000℃. The invention has simple structure and convenient operation. Due to manual operation and intermittent operation, the working conditions are poor and the efficiency is low. Inadequate material allocation will lead to incomplete combustion, which is not suitable for solid wastes with large amount of garbage and difficult to burn.
3. Gasification pyrolysis incinerator
The gasification pyrolysis incinerator has two incineration chambers, the first combustion chamber and the second combustion chamber. The shell is welded by steel plates, and the inside is made of refractory. The furnace is separated by a furnace wall. In the whole incinerator, the moving direction of the airflow is constantly changed in the vertical direction, so that the combustible gas and combustible dust particles coming out of the first combustion chamber are fully mixed and completely burned.
Garbage enters from the hopper at the upper part of the front end of the incinerator through the chute and is sent into the combustion chamber through the pneumatic furnace door. The waste entering the first combustion chamber is heated by the refractory wall or disposable burner through temperature adjustment, and the air in the first combustion chamber is blown in from the bottom, top and front. Before entering the second combustion chamber, the large particles are burned out through the air nozzle installed at the bottom of the furnace. There are two ash conveyors at the bottom of the first combustion chamber, which automatically rotate the garbage, convey the ash to the ash chamber, and finally enter the ash hopper after burning out. The unburned flue gas is mixed at the inlet of the secondary combustion chamber and completely burned in the secondary combustion chamber. The primary combustion chamber temperature is 500℃-800℃, the secondary combustion chamber temperature is 900℃- 1 100℃, and the residence time is more than 2 seconds.
The auxiliary burner is installed on the side walls of the first combustion chamber and the second combustion chamber, and is used when the incinerator is started and the residual heat value is low, so as to keep the furnace temperature.