JPS6113530B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the degree of drying of waste in a drying chamber of a solid waste incinerator.

The operation and operation of conventional solid waste incinerators relies entirely on manual labor, with operators visually inspecting the interior of the incinerator and
It has been operated experimentally. However, solid waste
Since its moisture content and properties constantly fluctuate, it is not possible to adequately respond to these fluctuations, resulting in incomplete drying, resulting in insufficient combustion in the combustion chamber, and a large amount of unburned material. On the contrary, the drying becomes excessive, and a considerable amount of waste is already burned in the drying chamber, causing problems such as the combustion heat causing significant damage to the drying chamber, and therefore, the drying operation is extremely complicated. There were drawbacks that required skill.

In view of the current situation, the present invention continuously detects the moisture content of waste by changing the water reduction rate of radio waves, controls the supply amount of waste based on the measured value signal, and controls the water content at the entrance and exit of the drying chamber. The temperature of the drying combustion gas is detected, and the signal of the difference between both temperatures is calculated from the measured value, which is calculated from the moisture content of the waste, the amount of waste supplied, and the temperature of the drying combustion gas at the exit of the drying chamber, and is the same as the reference signal. By controlling the flow rate of the drying combustion gas, the dryness of the waste in the drying chamber can be maintained at a constant level without relying on the operator's experience, preventing incomplete combustion in the combustion chamber, and drying can be achieved. A method for preventing damage due to excessive combustion in a chamber is provided, and will be described in detail below based on an illustrated embodiment.

In the figure, reference numeral 1 is a garbage input hopper, and when the waste input here passes through a chute 2 connected to the garbage input hopper 1, a moisture meter 3
The moisture content is measured by The water content is measured by taking advantage of the fact that water has a particularly high dielectric constant. In other words, when radio waves 4 are transmitted from the side of chute 2 through which waste is passing and passed through the waste, the water reduction rate of the radio waves changes depending on the moisture content of the waste, so this behavior can be utilized. It is possible to measure the moisture content of waste. The moisture content of the waste thus measured is supplied to the waste supply amount calculation device 5 as an electric signal. When the moisture content of the waste is within a preset range, the waste supply amount calculation device 55 operates a waste supply pusher 7 for supplying the waste in the chute 2 to a drying chamber 6 such as a rotary kiln. A command signal is issued to the waste feed pusher control device 8 to maintain the operating frequency at the set value. When the moisture content of the waste exceeds a preset range, the amount of waste supplied to the drying chamber 6 is reduced in accordance with the moisture content to improve the dryness of the waste in the drying chamber, that is, at the outlet of the drying chamber. The waste supply amount calculation device 5 issues a command signal to the waste supply pusher control device 8 so that the moisture content of the waste can be maintained substantially constant.

The operation frequency V of the waste supply pusher is determined by the waste supply calculation device 5 according to the moisture content η ₁ of the waste as explained above.
Specifically, in addition to the moisture content η ₁ of the waste, it is determined by taking into consideration the maximum operating frequency V ₀ of the waste feed pusher and the target moisture content η ₂ ^* of the waste at the outlet of the drying chamber. That is, in the waste supply amount calculation device 5, the constant maximum operating frequency V ₀ of the waste supply pusher and the target water content of the waste at the outlet of the drying chamber are calculated based on the measured value of the constantly changing moisture content η ₁ of the waste. Using η ₂ ^* , V ₀ (η ₁ −
η ₂ ^* ) is always calculated, and it is always checked whether this calculated value is larger than a preset maximum value K. Note that V ₀ (η ₁ −η ₂ ^* ) is an amount corresponding to the expected water content loss of the waste in the drying chamber 6. When the amount corresponding to the expected moisture loss of the waste in the drying chamber 6 is smaller than or equal to a preset value, that is, when V ₀ (η ₁ - η ₂ ^* )≦K, the operating frequency of the waste feed pusher is Since V can be the maximum operating frequency of the pusher V ₀ ,
The garbage supply amount calculation device 5 determines the maximum operation frequency of the garbage supply pusher 7 in the garbage supply pusher control device 8.
Issue a command signal to take V ₀ . Next, when the amount corresponding to the expected moisture loss of the waste in the drying chamber 6 is larger than the preset maximum value, that is,
When V ₀ (η ₁ - η ₂ ^* )>K, the operation frequency V of the garbage supply pusher cannot be the maximum operation frequency V ₀ of the pusher, and the maximum operation frequency V 0 of the garbage supply pusher within the range of the set value is The operating frequency V is V(η
₁ - η ₂ ^* )=K. That is, since the maximum operating frequency V of the waste feed pusher within the set value range is expressed by K/η ₁ −η ₂ ^* , which is a function of the moisture content η ₁ of the waste,
The garbage supply amount calculation device 5 calculates the amount of garbage supply pusher 7 to the garbage supply pusher control device 8 by K/η ₁ −η
Issue a command signal to take ₂ ^* .

The waste thus supplied to the drying chamber 6 is agitated in the drying chamber 6 and at the same time comes into contact with the drying combustion gas supplied from the drying chamber 9 and is dried, but the degree of dryness is maintained constant. In order to achieve this, the temperature at the inlet and outlet of the drying chamber 6 is detected by a thermocouple or other temperature detector, the temperature difference is calculated by a temperature difference calculation device 10, and compared with a target temperature difference to make sure that both are the same. The flow rate of the drying combustion gas in the drying chamber 6 is controlled accordingly.

Here, an example of a method for calculating a target temperature difference to be compared with an actually measured temperature difference will be explained. When the waste is ideally dried, the following equation holds true regarding the exchange of heat in the drying chamber 6.

^{T * =} T _{2 −} ^T _{1 …} ( ^{1 )} Temperature difference between the outlet and inlet T ₁ : Temperature at the inlet of the drying chamber T ₂ : Temperature at the outlet of the drying chamber X ^* : Flow rate of the drying combustion gas passing through the drying chamber during ideal drying η ₂ ^* : Moisture content of waste at the exit of the drying chamber when ideally dried Q ^* : Calorific value k due to partial combustion of waste in the drying chamber when ideally dried, : Constant Waste The drying rate of is determined by the flow rate of the drying combustion gas passing through the drying chamber 6 and the temperature at the outlet of the drying chamber, so when drying is ideal, the following equation approximately holds true.

v(η ₁ −η ₂ ^* )=αX ^* +βT ₂ +γ (3) However, α, β, and γ are constants.

From equations (1), (2), and (3), when drying is ideal, the temperature difference (target temperature difference) T ^* between the outlet and inlet of the drying chamber 6 is expressed by the following equation. .

T ^* = αkv(η ₁ −η ₂ ^* )−Q ^* /v(η ₁
-η ₂ ^* ) - βT ₂ -γ Therefore, T ^* is the moisture content η ₁ of the waste at the inlet of the drying chamber 6, the amount of waste fed (operating frequency V of the waste feed pusher), and the amount of water at the outlet of the drying chamber 6. Temperature T ₂
This value is determined based on each variable, and is always calculated in the target temperature difference calculation device 11 according to the values of these variables.

The final flow rate control of the drying combustion gas is
The target temperature difference calculated as described above is compared with the actually measured temperature difference, and the duct damper opening calculation device 12 calculates the same so that the difference is the same, and the duct damper
This is done by adjusting the opening degree of 4.

As is clear from the above description, the method of the present invention continuously measures the moisture content of solid waste before supplying the solid waste to a drying chamber connected to a combustion chamber of a solid waste incinerator. The amount of solid waste to be supplied is calculated based on this measured value, and the solid waste is supplied to the drying chamber while controlling the supply amount of solid waste via the solid waste supply control device based on the signal, and then the solid waste is supplied to the drying chamber. The temperature of the drying combustion gas at the inlet and outlet of the drying chamber is continuously measured, and the temperature difference signal calculated from both temperatures is used to calculate the moisture content of the solid waste before supplying it to the drying chamber, the amount of solid waste supplied, and the drying chamber. A drying control method in a solid waste incinerator that controls the flow rate of drying combustion gas so that it is the same as the target temperature difference signal calculated from the outlet temperature, and the drying control method in a solid waste incinerator Damage to the drying chamber due to an increase in materials or excessive combustion within the drying chamber can be prevented, and operation is simplified and can be operated easily.

[Brief explanation of drawings]

The drawing is a flow sheet showing one embodiment of the method of the present invention. 1...garbage input hopper, 2...chute, 3...moisture meter, 4...radio wave, 5...garbage supply amount calculation device, 6...
Drying chamber, 7... Garbage supply pusher, 8... Waste supply pusher control device, 9... Combustion chamber, 10... Temperature difference calculation device, 11... Target temperature difference calculation device, 12... Duct damper opening degree calculation device, 13... Duct damper Control device, 14... duct damper.

Claims (1)

[Claims] 1. Before supplying solid waste to the drying chamber connected to the combustion chamber of a solid waste incinerator, the moisture content of the solid waste is continuously measured by changes in the attenuation rate of radio waves, and based on the measured value, The amount of solid waste to be supplied is calculated, and the amount of solid waste to be supplied is controlled by the solid waste supply control device based on the signal, and the solid waste is supplied to the drying chamber. The temperature of the drying combustion gas at the inlet and outlet is continuously measured, and the temperature difference signal calculated from both temperatures is used to determine the moisture content of solid waste before supply to the drying chamber, the amount of solid waste supplied, and the output of the drying chamber. A method for controlling drying in a solid waste incinerator, comprising controlling the flow rate of combustion gas for drying in a drying chamber so as to be the same as a target temperature difference signal calculated from the temperature of combustion gas for drying in a solid waste incinerator.