JPS58163499A - Apparatus for heating and dehydrating sewage sludge - Google Patents

Abstract

PURPOSE:To perform efficient dehydration, by providing a suction pipe equipped with a vacuum pump and a drain-separating means at an air-tight chamber and several drying drums equipped with means for supplying the part of heating gas and means for discharging said gas in the air-tight chamber. CONSTITUTION:A suction pipe 24 equipped with a vacuum pump 22 and a drain- separating means 23 is provided at an air-tight chamber 21 to hold the interior at about 0.5kg/cm<2>. Five drying drums 25, 25', 25'', 25'''' are provided inside the air-tight chamber 21. Each of the drying drums has a means 26 for supplying the part of heating gas at one end and a discharging means 28 equipped with a drain-separating means 27 at the other end. In addition, two upper and lower net belts 31, 32 constituted with a heat-transmitting wire net or the like having air- permeable pores of 20-200mum in diameter are provided around the peripheries of the drying drums 25... and guide rollers 29, 29' in the air-tight chamber 21.

Description

[Detailed description of the invention] We are developing an incinerator.

The present invention is a sewage sludge heating and dewatering device used in place of the sewage sludge heater 3 in the sewage sludge incinerator shown in FIG. Explain the sewage sludge incinerator.

In FIG. 1, sewage sludge with a moisture content of about 80% in a hopper 1 is heated by a feeding means 2 through a sewage sludge heater 3, and is heated to a sewage sludge drying furnace 4 having a fluidized sand bed. supplied to The drying furnace is supplied with the necessary amount of drying drum heated to 200 to 400 °C from the space below the sand bed, and this gas fluidizes the sand bed, so that the supplied sludge is pulverized by this fluidized sand bed. It is dried while being washed.

The product produced in the drying oven 4 is sucked in by the blower 11 and separated by the separation means 5 into solid and gas components. The solids are dropped into a hopper provided below the separation means 5, and are supplied in constant amounts to the sewage sludge combustion furnace 7 by the powder supply means 6 provided at the bottom of the hopper.

In Figure 1, these combustion furnaces are incomplete combustion furnace I and complete combustion furnace 7.
A two-stage combustion system is shown, which consists of two stages.
By using staged combustion, the amount of NOx generated can be significantly reduced. The air necessary for these combustions is preheated by a blower 13 through an air preheater 14 provided around the outer periphery of the complete combustion furnace T', and then distributed proportionally and supplied to the incomplete combustion furnace 7 and the complete combustion furnace 7. be done. The product of the complete combustion furnace 7' is sucked in by a blower 10, passes through a heat exchanger 8, passes through a filter 9, and is exhausted by the blower 10. Further, the gas separated by the separation means 5 is pressurized by a blower 11 and circulated through a circulation pipe 12, and the heat exchanger 8 is provided in the circulation path,
The temperature is raised to -200°C to 400°C. The amount of gas heated by the heat exchanger 8 is the amount A of gas supplied as a drying gas to the drying furnace 4 and the amount B of gas generated from the sewage sludge supplied in the drying furnace 4. Of these total amounts, the same amount of gas as A is again supplied to the drying oven 4 as the required drying gas amount,
The remaining gas, which is the same amount as B, is supplied to the heater 3 as a heating gas. After passing through the heater 3 and heating the sewage sludge, the gas passes through the drain separation means 15 and is discharged from the system by the drain separation means, after which it is supplied to the combustion furnace 7 through the gas supply pipe 16. The sewage sludge produced by the drying furnace 4 is mostly water vapor, and the remaining gas is supplied to the combustion furnace after passing through the heater and draining the water vapor to the outside of the system.

Therefore, a feature of this incineration system is that it can reduce the amount of boiling water in the combustion furnace. This sewage sludge incineration equipment produces sewage sludge with a relatively high moisture content or dried sewage sludge, which has a calorie of 3500 Ka4/
This incineration system is suitable for incinerating sewage sludge with a low calorific value of 9 or less, and is capable of smoothly incinerating sewage sludge using only its own calories, almost eliminating the need to replenish fuel for incineration and incineration.

However, since it is desirable that the amount of water supplied into the combustion furnace 7 is even smaller, the water contained in the sewage sludge can be used instead of the heater 3. In order to extract as much as possible from the system,
A number of conventional heating dehydration devices have been studied.

FIG. 2 is an explanatory diagram showing a heating dehydration device d according to the present invention, which is used in place of the heater 3 in FIG. 1 in place of a general heat exchange type heater.

In FIG. 2, reference numeral 21 denotes an airtight chamber whose interior is maintained at a negative pressure of about 0.5 kg/cr1, and a suction pipe 24 having a pachium pump 22 and a drain separation means 23 is installed in the airtight chamber 21 to provide the above-mentioned σ) negative pressure. can be maintained.

There are five drying drums 2525' in the airtight chamber 21,
25"...25"". Each of these drying drums has a cooling gas supply means 26 at one end and a discharge means 28 having a drain separation means 27 at the other end. I have (・ru.

In addition, several guide rollers 29, 29,
. . . and 30.31 . . . are provided. Also, inside the airtight chamber 21, two upper and lower netpels 31 and 32 made of heat conductive wire mesh or the like having ventilation holes of 20 μm to 200 μm in diameter are provided around the outer periphery of the drying drum and the guide roller, respectively. The airtight room 21
σ] A feeding means 33 for forcibly feeding sewage sludge in fixed quantities, such as a screw type extruder, is provided on the supply side, and sewage sludge is fed between these two upper and lower net belts 31 and 32 with an average thickness. so that Further, in order to scrape off the dried sewage sludge from the net belts 31, 32 on the discharge side of the airtight chamber (21J), stripping rollers 34, 34 having several elastic blades are provided to rotate. A carrying means 35 is provided for carrying the sewage sludge scraped off by these stripping rollers out of the airtight chamber and transferring it to the next step, such as a drying oven having a fluidized sand bed.

Note that the drying drum used in the present invention is, for example, a third drying drum.
The structure is shown in FIG. That is, the shafts 41 and 42 at both ends of the drying drum 25 are connected to both side walls 43 of the airtight chamber.
．． The drive means is provided on the outside of the right side wall, and this drive means is fixed to the shaft 41 at a position 4E slightly outside the side wall 43, for example. A sprocket wheel 45 is provided at the same time, and the drum is rotated by this sprocket wheel 45. Further, a coupling 26 is provided at the right end of the shaft 41, and is airtightly connected to a heating gas supply branch pipe 46. The high temperature heating gas is supplied into the drum from the coupling 26 through the hollow hole in the shaft 41. Conical bodies 4γ are provided in the drum with the bottom facing to the right, and the gas is supplied to the outer space of these conical bodies 47. This space is fixed by the left side wall and peripheral wall of the drum. The four sheets are divided into four segments.

The coupling 28 is provided on the left side of the shaft 42, and the shaft 42 has a hollow structure.
and a discharge pipe 49 are airtightly connected, and the discharge pipe 49
A drain separation means 27 is provided in the drain separation means 27 . The structure is such that the condensed condensate inside the drum is naturally discharged from the shaft 42 into the discharge pipe 49 when the segment reaches the upper position due to rotation of the drum.

This airtight chamber 21 has a suction pipe 2 having a vacuum pump 22.
By providing 4, it is possible to maintain an extremely negative pressure, and therefore the water contained in the sewage sludge evaporates at 80°C.

Netpel) at 31.32. While the sandwiched sewage sludge passes around several drying drums, it is heated from different sides to promote evaporation, and the gas produced by the evaporation is transferred to the suction pipe 24.
The drain is sucked by the vacuum pump 22 and taken out from the system by the drain separation means 23. Therefore, when sewage sludge with a moisture content of 80 is supplied to this heating dehydrator, it can be converted into sewage sludge with a moisture content of 60 and supplied to the next process by the discharge means 35. That is, 100 kg of sewage sludge with a moisture content of 80 g at the time of supply has a composition of 20 kg of fixed content and 80 kg of water. 50 kg of water is taken out from the suction pipe 24 by this heating dehydrator. The amount of sewage sludge taken out from the discharge means 35 is 50 Kq and the moisture content is 60%.

Its composition is 20Kq, which is the same as when it was supplied, but the moisture content is greatly reduced to 30Kg, dewatering is carried out, and the next process of incineration of sewage sludge is carried out very smoothly.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a sewage sludge incinerator previously developed by the present inventor. - FIG. 2 is an explanatory diagram showing a side cross section of the sewage sludge heating dehydration apparatus according to the present invention. Figures 3 and 4
The figures are a side sectional view and a %-IV sectional view of a drying drum used in the heating dehydration apparatus of the present invention. 21 is an airtight chamber, 22 is a vacium pump, 23 is a drain separation means, 24 is a suction pipe, 25 is a drying drum, 26 is a sewage sludge gas supply means for drying, 27 is a drain separation means,
28 is a discharge means, 29.30 is a guide roller, 31.3
2 is a net belt, 33 is a sewage sludge feeding means, 34 is a stripping means, and 35 is a carrying out means. 41.42 is the shaft of the drying drum, 43.44 is the side wall, 4
5 is a sprocket wheel, 46 is a branch pipe for supplying drying sewage sludge gas, 47 is a cone, 48 is a plate, and 49 is a discharge pipe.

Claims (1)

[Claims] An airtight chamber 21 is provided, and a vacuum pump 22 and a suction pipe 24 having a drain separation means 23 are provided in the airtight chamber so that the airtight chamber 21 is maintained at a negative pressure. A drum 25.25...... is provided,
These drying drums are provided with a heating gas supply means 26 and a discharge means 2B, and the discharge means 28 is provided with a drain separation means 27.
and several guide rollers 29.2 in the airtight chamber 21.
9...... and 30.30...
... is provided in the airtight room, both of which are air permeable.
Net belts 31 and 32 are respectively engaged with these drying drums and guide rollers, and sewage sludge is supplied to the supply side of the airtight chamber between these two upper and lower net belts. A sewage sludge feeding means 33 is provided,
A stripping means 34, 34 for scraping off the dried sewage sludge from the net belt is provided on the discharge side of the airtight chamber, and a carrying-out means 35 takes out the scraped sewage sludge from the airtight chamber 21 and transfers it to the next process. A heating dewatering device for sewage sludge equipped with