JPS6042368B2 - Sewage sludge resource recovery equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, sewage sludge was considered to be a waste that should be incinerated with supplementary fuel.

The applicant has been conducting research on the incineration of sewage sludge for many years, and has developed a device that skillfully uses its own calories to incinerate even low-calorie sewage sludge without using much auxiliary fuel. A patent application has been filed (Japanese Patent Application No. 169165-1983).

Prior to explaining the present invention, the apparatus for which a patent application has been applied will first be explained with reference to FIG. In Figure 1, sewage sludge that has been dewatered to a moisture content of approximately 90% by mechanical dewatering is supplied into a hopper 1, and the sewage sludge in the hopper 1 is forcibly fed to a screw conveyor installed at the bottom of the hopper. by the means 2 is first supplied to the sewage sludge heater 3;
A part of the gas that has been heated to a high temperature by the heat of flue gas in the heat exchanger 8 which is a later step is supplied to the heater as a heating gas, and the high temperature gas is supplied through the heater 3. The sewage sludge heated by the heating gas and made fluid is then supplied to a drying furnace 4 having a fluid flow method, and is fed to the drying furnace in a subsequent step by a heat exchanger 8 using the heat of flue gas. A necessary amount of the gas heated to a high temperature is supplied as a drying gas, and the dried product of the drying oven is separated into a solid component and a gas component by a separating means 5, and the solid component is separated into powder. Body supply means 6
The heating gas supplied to the two-stage combustion furnaces 7 and 7' is cooled to a slightly lower temperature after passing through the heating furnace 3, and then taken out. After the fuel is supplied and the drain is removed, it is supplied as fuel to either of the two-stage combustion furnaces 7 and 7'. Combustion air to be supplied to the combustion furnaces 7, 7'' is preheated through an air preheater 14 provided as a jacket of the combustion furnace 7'', and then supplied to the two-stage combustion furnaces 7, 7''. The combustion generated gas first passes through the heat exchanger 8.
After being cooled to a slightly lower temperature through heat exchange, the gas is passed through a filter 9 to remove ash and exhausted through an exhaust blower 10. The gas separated by the separation means 5 passes through a blower 11. Air is sent through the circulation pipe 12 including the heat exchanger 8, heated by the heat of the flue gas by the heat exchanger 8, and the required amount of gas is supplied to the drying oven 4 as a drying gas. After the necessary amount is supplied to the drying oven, the gas is supplied to the heater 3 as a heating gas. However, subsequent research has shown that sewage sludge is not something that should be simply incinerated and treated because it potentially contains many sources, but that the dry product produced by drying sewage sludge can be used as an agricultural soil improvement material. It has been found that the ash can be effectively used as a variety of resources, such as as a raw material for producing gas fuel, or by making the ash into lumps and using it as aggregate for cement.

In the sewage sludge incinerator shown in FIG. 1 mentioned above, the solid content of the dried sewage sludge obtained by the separation means 5 is about 50% ash as shown in FIG. Approximately 45% of the total is volatile matter, and the remaining 5%
is the fixed carbon content.

Therefore, it is possible to convert the sewage sludge incinerator shown in Figure 1 into the resource recovery equipment shown in Figure 3, and to effectively utilize the resulting gas fuel and lump ash as resources. Wear. That is, the third
The resource recovery device shown in the figure has a gasification device 21 and an ash processing device 22. Incidentally, reference numeral 23 indicates a case where the dried sewage sludge solid content is directly used for agricultural purposes, that is, as a soil conditioner. Before explaining the resource recovery device according to the present invention, the dry sludge gasification device 21 and the dry sludge ash processing device 22 used in the device of the present invention will be explained respectively.

4 and 5 show a dry sludge gasifier 21 used in the apparatus of the present invention shown in FIG. A chamber 32 is provided, and a dry distillation chamber 33 is provided on the outer periphery of the combustion chamber. A dry sludge supply means 6'' is provided at the top of the dry distillation chamber 33, a supply pipe 41 for volatilization promoting gas such as superheated steam is provided at the bottom, an ash removal pipe is provided at the bottom, and a gas supply means 6'' is provided at the top. It has a structure in which a take-out pipe 24 is provided.

A part of the solid content of the dried sewage sludge separated by the separation means 5 is supplied to the gasification device 21 by the powder supply means 6'', where it is heated in a combustion chamber and supplied with volatilization-promoting gas such as superheated steam. When the dried sludge is allowed to stagnate in an atmosphere of about 500°C to 700°C using stirring blades, most of the volatile matter in the dried sludge is vaporized, and it is taken out by the gas extraction pipe 24 and used as fuel gas. can be used as a source.

The combustion exhaust gas from the combustion exhaust gas discharge pipe 39 provided at the upper part of the combustion chamber is guided to the heat exchanger 8 through the pipe 27. The ash is taken out from the ash removal pipe and sent to the ash processing device 22 by means of transportation. The heating gas sent to the heater 3 can be supplied to the burner 31 after removing the condensate through the condensate separating means 15 to perform necessary combustion.
FIG. 6 shows a dry sludge ash processing device 22 used in the device of the present invention shown in FIG. A dry sludge supply pipe 52 is provided connected to the cyclone combustion chamber to supply another part of the dried sludge, and a primary air supply pipe 54 is provided in the tangential direction on the peripheral side wall of the cyclone combustion chamber, and a primary air supply pipe 54 is provided in the lower part of the cyclone combustion chamber. A slightly constricted portion 55 is provided, a water tank 56 is provided directly below the constricted portion, a flame path 60 is provided laterally between the cyclone combustion chamber 51 and the water tank 56, and a It has a structure in which a second stage combustion chamber 61 is provided, and a secondary air supply pipe 62 is provided in the second stage combustion chamber 61.

The cyclone combustion chamber 51 can be supplied with ash taken out from the ash removal section of the gasifier 21 by means of a transport means 25. The flame generated within the cyclone combustion chamber 51 is a hollow flame with 12
A high-temperature flame of 00° C. or higher can be formed in a swirling manner. The ash content of sewage sludge is an alkaline salt containing relatively large amounts of sodium and potassium, and the temperature ranges from 700℃ to 80℃.
Since it has a relatively low melting point of 0° C., it easily melts on the inner circumferential wall surface and flows downward through the inner circumferential wall from the constricted portion 55, forming droplets of a certain size and falling downward into the water tank 56. It falls into the interior and immediately solidifies into a lump. Therefore, it can be taken out from the take-out tube 59 as a lump of an appropriate size and collected into the container 26. Since this mass is an alkali salt with high formable hardness, it can be used as a resource as a reinforcing material for concrete. The combustion exhaust gas discharged from the second stage combustion chamber 61 is guided to the heat exchanger 8 by the pipe 28. In the sewage sludge resource recovery apparatus of the present invention, as shown in FIG. A necessary amount of the air is fed through the circulation circuit 12 and is supplied to the drying oven 4 as a drying gas. In the sewage sludge incinerator, a portion of the solids separated by the separation means 5 is supplied to the powder supply means 6 and 6''. Therefore, the gaseous fuel is supplied to the gasification device 21 and taken out from the gas extraction pipe 24 provided at the top of the gasification device 21, and the other part of the solid fraction separated by the separation means 5 is removed. The section supplies the cyclone combustion chamber to the first by means of powder supply means 6 and 6''.
The ash is supplied to the cyclone combustion chamber of the two-stage combustion ash processing device 22 which is a stage combustion chamber, and the gasification device 21
The ash taken out from the ash extraction pipe provided at the bottom of the ash processing device 22 is also supplied to the cyclone combustion chamber of the ash processing device 22, and the water tank provided at the bottom of the cyclone combustion chamber of the ash processing device The ash lumps are taken out from the ash lump container 26, and the combustion exhaust gas from the gasifier 21 and the combustion exhaust gas from the second stage combustion chamber of the ash processing equipment 22 are transferred to the heat exchanger 8 through pipes 27 and 28, respectively. This is a resource recovery device for sewage sludge that is supplied to This resource recovery device not only incinerates sewage sludge, but also recovers gas fuel from the pipe 24 and ash lumps, which serve as aggregate for concrete, as resources by means of their removal.

[Brief explanation of the drawing]

FIG. 1 shows a sewage sludge incinerator previously developed by the present applicant and the present inventor. FIG. 2 is a graph showing the composition of solid components of dried sewage sludge and the volatilization rate of volatile components at various temperatures. FIG. 3 shows a sewage sludge resource recovery device according to the present invention. Figure 4. Fifth
The figures are a side sectional view and a plan view of a gasifier 21 used in the resource recovery apparatus of the present invention. FIG. 6 is a side sectional view of the ash processing device 22 used in the resource recovery device of the present invention. 1 is a hopper, 2 is a screw conveyor, 3 is a heater, 4 is a sewage sludge drying furnace having a fluidized sand bed, 5 is a separation means, 6, 6'', 6''. 6″″″ is a powder supply means, 8
is a heat exchanger, 9 is a filter, 10 is an exhaust fan, 11 is a blower, 12 is a circulation circuit, 15 is a drain separation means, 21 is a gasifier, 22 is an ash processing device, 24 is a gas extraction pipe, 25 is a ash supply means, 26 a container for ash lumps, 27;
28 is an exhaust gas pipe, 31 is a burner, 32 is a combustion chamber, 33 is a dry distillation chamber, 51 is a first cyclone combustion chamber, 55 is a squeezed part, 56 is a water tank, 59 is an ash lump removal pipe, 61 is a second Stage combustion chamber.

Claims (1)

[Claims] 1. A sewage sludge drying furnace and a separation means for separating the dried product of the sewage sludge drying furnace into a gas component and a solid component are provided, two powder supply means are provided for the solid component separated by the separation means, and 1. The powder supply means is connected to the dry distillation chamber of the gasifier, which includes a combustion chamber and a dry distillation chamber, and the other powder supply means is connected to an ash processing device, which includes a first cyclone combustion chamber, a water tank, and a second stage combustion chamber. A gas extraction pipe is provided in the dry distillation chamber of the gasifier connected to the first cyclone combustion chamber, and a means for supplying ash produced in the dry distillation chamber is connected to the first cyclone combustion chamber.
An ash lump removal means is provided in the water tank at the lower part of the cyclone combustion chamber, and the exhaust gas from the combustion chamber of the gasifier and the exhaust gas from the second stage combustion chamber of the ash treatment device are discharged through a heat exchanger. . A sewage sludge material recovery device constructed such that the gas separated by the separation means is supplied to a sewage sludge drying furnace through a blower and a heat exchanger.