JPH0775718B2 - Sludge oil conversion reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention thermochemically reacts organic sludge such as excess sludge generated from a microorganism treatment apparatus such as an activated sludge treatment apparatus under high temperature and high pressure conditions, The present invention relates to a sludge oiling apparatus which obtains a combustible liquid and treats the sludge, and uses the combustible liquid as a thermal energy source or an electric energy source for the thermochemical reaction.

[Conventional technology]

A sludge oil conversion technology has been proposed as one of methods for treating organic sludge such as surplus sludge generated from various microbial treatment devices.

In other words, it is a technology to obtain fuel oil from biomass by thermochemically reacting organic sludge under high temperature and high pressure conditions.

Conventionally, a device for obtaining asphalt and fuel oil from sewage sludge has been proposed as this type of technology (EPA Project Summary EP
A-600 / S2-81-242 Dec, 1981), but it is only a conceptual flow, and no concrete description of reactor type, shape, etc. is made.

On the other hand, research on obtaining fuel oil from wood is being conducted at the US Mining Bureau, and bench-scale experiments are being conducted. The reactor in this method is a fully mixed reactor (CST
R), and a scraping surface type preheater is installed as a preheater in the preceding stage. The wood sent to the preheater and reactor has been made fluid by pretreatment such as oil slurry (Wood: Oil = 2: 8) or acid hydrolysis.

[Problems to be solved]

In the conventionally proposed scraping surface heat exchange type pollutant oilification reactor 6 shown in FIG. 1, a jacket pipe J is provided on the outer periphery, and a heat medium 8 described later flows into the jacket pipe J,
A scraper B is provided all over the inside of the reactor 6 to scrape the inner wall surface to increase the heat transfer coefficient and prevent clogging. However, according to the experiments conducted by the present inventors, sludge is clogged in the front stage part of the reactor, that is, the unreacted part having a low temperature, and the discharge pressure of the press-fitting device is abnormally increased. It is considered that this phenomenon was caused by the fact that fibrous substances contained in sludge (in the case of sewage sludge, hair, etc.) were entangled with the scraper itself, which grew and caused blockage.

The present invention has been made in view of the above points, and its purpose is to thermochemically react organic sludge under conditions of high temperature and high pressure to obtain a flammable liquid.
An object of the present invention is to provide a sludge oilification reactor that stably treats organic sludge for a long time without causing troubles such as a clogging problem.

[Means for solving problems]

The present invention is a sludge oil conversion reactor, a scraper is installed in the latter part of the inside of the oil conversion reactor, and a screw mechanism is installed in the front part of the oil conversion reactor, and if necessary, from the outlet to the inlet of the reactor. The present invention relates to a sludge oil conversion reactor characterized by having a circulation line.

[Action]

The details of the present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 2 is an explanatory view showing the flow of sludge oilification reaction according to the present invention, in which the organic sludge 1 is first pre-dehydrated by a dehydrator 2 such as a centrifuge or a belt press type dehydrator, and the dehydration is performed. The sludge 3 is supplied by a press-fitting device 4 to a reactor 6 having a preheating section 5A and a reaction section 5B. If the organic sludge contains an excessively large amount of water, a large amount of heat is consumed in the thermochemical reaction described later. Therefore, it is desirable that the water content in the dehydrating device 2 be 80% or less. Furthermore, in the thermochemical reaction to be described later, it is better to allow an organic sludge to coexist with an alkaline component, so that the reaction efficiency is improved, so that the organic sludge is pre-cured with sodium carbonate, potassium carbonate, sodium formate, potassium formate, potassium hydroxide, It is preferable to add an alkaline component such as sodium hydroxide or lime. A high-pressure slurry pump can of course be used as the press-fitting device 4 described above, but since dehydrated sludge must be supplied at a considerably high temperature, it is preferable to use a press-fitting device that combines a cylinder and a piston as described below.

That is, as shown in FIG. 3, a cylinder 33 having a built-in piston 32 is installed, and a water tank 35 having water level gauges 34A and 34B is installed. The cylinder 33 at the lower part of the water tank 35 is installed.
The upper part of the cylinder is communicated with a pipe 37 via, for example, a reciprocating pump, and the lower part of the cylinder 33 is connected with a supply pipe 38 and a discharge pipe 39 for the dehydrated sludge.

The operation of the press-fitting device 4 shown in FIG. 3 is carried out by operating the valves 40, 41 with the upper portion of the piston 32 filled with water as shown in the figure.
Opening the opening and driving the supply pump 42 to supply the dehydrated sludge 3
It flows from 38 through the lower part of the cylinder 33. With the inflow, the piston 32 rises, and the water above the piston 32 flows into the water tank 35 via the pipe 37 and the valve 41. The water tank 35
Since the water level inside rises according to the capacity of the supplied dehydrated sludge 3, the supply of the dehydrated sludge 3 is stopped at the point when the water level reaches the water level meter 34A. Then, the valves 41 and 40 are closed and the reciprocating pump 36 is driven to press-fit the water in the water tank 35 and pressurize the pressure in the cylinder 33 via the piston 32. Then cylinder 33
After sufficiently increasing the internal pressure, open the valve 43 and open the cylinder 33.
The dewatered sludge 3 therein is press-fitted through water and the piston 32. With the press-fitting, the piston 32 descends and the dehydrated sludge 3 in the cylinder is supplied to the reactor 6 described later. When the water level in the water tank reaches the water level gauge 34B, press-fitting is stopped and the above operation is repeated.

The use of the above-mentioned device as the press-fitting device 4 has the advantages that the dehydrated sludge can be supplied at a high pressure, the manufacturing cost is low, the operation is simple, and the automatic control is easy.

A scraped surface heat exchanger can be used for the reactor 6, and the preheating section 5A in the preceding stage indirectly preheats the dehydrated sludge 3 by using a heat medium 8 to which heat is given by a cooler 7 described later. The latter reaction section 5B indirectly heats the dehydrated sludge 3 by the heat medium 8 heated by the first heat exchanger 24 described later, and usually has a temperature of 250 ° C to 350 ° C and a steam pressure of the temperature. The organic sludge 3 is thermochemically reacted at a pressure corresponding to or higher than.

Thus, when the organic sludge is treated at high temperature and high pressure, the biomass is thermochemically modified, various combustible liquids are produced, and at the same time, the fluidity is changed to a very good one. Next, a mixture slurry 9 of a solid substance and a flammable liquid that has passed through the reactor 6
Is supplied to the cooler 7 in a pressurized state and indirectly cooled by the heat medium 8. By using the heat medium 8 to which heat has been given by cooling as the heat source of the preheating section 5A, the heat given by the reactor 6 is effectively recovered. As the cooler 7, a thin film flow-down heat exchanger, a full pipe heat exchanger,
A scraped surface heat exchanger or the like can be used, but since the mixture slurry 9 has extremely good fluidity, it is preferable to use a thin film flow-down heat exchanger having the best thermal efficiency.

The mixture slurry 9 thus cooled is then supplied to the atmosphere opening device 10 so that the state under pressure is changed to the state under normal pressure.

The atmosphere opening device 10 used here may be, for example, a receiving tank for receiving the mixture slurry 9 from the cooler 7 and a red down valve provided in the lower part of the receiving tank. However, the device shown in FIG. 4 is preferably used. desirable.

That is, ball valves 44A, 44B,
Multiple receiving tanks 45A and 45B having 44C and 44D, an inert gas cylinder 46 such as nitrogen, argon, helium, and a gas storage tank
47 and each of these valves 48-48 as shown in FIG.
55 and the back pressure valves 56 and 57 are connected to each other through respective pipes.

In the operation of the atmosphere opening device 10 shown in FIG. 4, first, the valve 54 and the valve 49 are opened to flow the inert gas from the inert gas cylinder 46 into the receiving tank 45A, and the pressure of the receiving tank 45A is adjusted to that of the cooler 7. Keep pressure almost equal. Note that this operation is necessary only at the beginning and is not necessary thereafter, as will be described later. Next, the ball valve 44A, the valve 48, and the valve 52 are opened to receive the mixture slurry 9 from the cooler 7 in the receiving tank 45A. The inert gas discharged from the receiving tank 45A in accordance with the reception flows into the receiving tank 45B through the valve 48, the back pressure valve 56, and the valve 52. Further, at this time, since the inert gas passes through the back pressure valve 56, by making the operating pressure of the back pressure valve 56 equal to the pressure of the cooler 7, the inert gas can gradually flow into the receiving tank 45B. it can.

After the prescribed amount of the mixture slurry 9 is received in the receiving tank 45A by such an operation, the valve 48 remains open and the ball valve 44 is opened.
A, the valve 52 is closed and the valve 51 is opened. In this way, the pressures in the receiving tank 45A and the receiving tank 45B are equalized because the inert gas communicates with each other via the valve 48 and the valve 51. Next, the ball valve 44C is opened to start the operation of receiving the mixture slurry 9 in the receiving tank 45B. On the other hand, on the receiving tank 45A side, the valve 48 is closed and the valve 50
And a small amount of pressurized inert gas remaining in the upper part of the receiving tank 45A flows into the storage tank 47, and the surplus inert gas is discharged to the outside through the back pressure valve 57. Since various gases are generated when the dehydrated sludge is reacted in the reactor 6, it is desirable to perform a deodorizing process as necessary at the time of the above-mentioned release. The operating pressure of the back pressure valve 57 is, for example, 5 Kg / cm.
If it is set to ² G, 5 Kg / cm ² G of pressurized inert gas remains in the upper part of the receiving tank 45A by this step. Then, by opening the ball valve 44B, the above-mentioned 5 Kg / cm ² G
The mixture slurry 9 can be sent to the outside, that is, to the floating separation tank 11 described later by the pressure of the residual gas.

When the discharge of the mixture slurry 9 from the receiving tank 45A is completed, the valve 5
0 is closed, the valve 49 is opened, and the inert gas discharged from the receiving tank 45B when the mixed slurry 9 is received in the receiving tank 45B is passed through the valve 51, the back pressure valve 56, and the valve 49 to the receiving tank 45A.
Flow into. In this case also, since the inert gas similarly passes through the back pressure valve 56, as described above, the receiving tank 45A gradually increases.
Can be flowed into. Then, as described above,
After the prescribed amount of the mixture slurry 9 is received in the receiving tank 45B, the valve 51 is kept open, the ball valve 44C and the valve 49 are closed, and the valve 48 is opened. After equalizing the pressure in both tanks by this operation,
The ball valve 44A is opened to start the operation of receiving the mixture slurry 9 into the receiving tank 45A, while the valve 53 is provided on the receiving tank 45B side.
Is opened and a small amount of pressurized inert gas remaining in the upper part of the receiving tank 45B flows into the storage tank 47, and the surplus gas is removed by the back pressure valve 57.
And then the ball valve 44D is opened to feed the mixture slurry 9 to the floating separation tank 11 described later.
As described above, the atmosphere opening device 10 shown in FIG. 4 sequentially receives the mixture slurry 9 in a plurality of receiving tanks and collects the inert gas discharged along with the receiving in the other receiving tanks.

By using the above-mentioned atmosphere release device 10, the mixture slurry 9 in the cooler 7 under high pressure can be stepped down to the atmospheric pressure with a relatively simple structure, and the consumption of the inert gas can be reduced. Is also small.

The mixture slurry 9 fed by such an atmosphere opening device 10 is subsequently fed to the flotation separation tank 11, and an oily substance which is a part of the flammable liquid floating in water from the flammable liquid in the mixture slurry 9 Collect 12 selectively. If some flammable liquid floating in water adheres to the solid matter in the liquid,
It is advisable to stir before supplying to the floating separation tank 11. As the flotation / separation tank 11, it is possible to use one in which the mixture slurry 9 is simply retained in the tank for a certain period of time and the floating oily substance 12 is scraped off by a skimmer or the like, or an oil separator having a so-called simple structure. The mixture slurry 9 from which the oily substance 12 has been removed by the floating separation tank 11 is then sent to the extraction tank 13, and the solvent 14 recovered by the solvent recovery device 20 described later is added and sufficiently stirred to extract the flammable liquid in the mixture slurry 9. To do. The extraction tank 13 may be of any type as long as it can bring the mixture slurry 9 and the solvent 14 into contact with each other in a necessary and sufficient manner. It is easy to stir the mixture of the mixture slurry 9 and the solvent 14 in the tank. Anything is fine.

As the solvent 14 to be used, a solvent that can extract all the flammable liquids in the mixture slurry 9 as much as possible and is easy to evaporate and recover is preferable. Usually, benzene, toluene, acetone, methylene chloride or the like is used.

The mixture 15 obtained batchwise or continuously from the extraction tank 13 is then fed to a three-phase separator 16 where it is separated into wastewater 17, solids 18 and extracts 19. The three-phase separator 16 is a so-called centrifuge, and it is possible to use a known one that separates the wastewater 17 having different specific gravities 17, the solid 18 and the extract 19 by centrifugal action. The extract 19 obtained by the three-phase separator 16 is then transferred to the solvent recovery device 20.
And indirectly heated by the heat medium 8 heated by the second heat exchanger 25, which will be described later, to evaporate the solvent 14 and recover the combustible liquid 21 which is the evaporation residue. In the drawing, the solvent 14 recovered from the solvent recovery device 20 is directly supplied to the extraction tank 13, but in reality, the gaseous solvent obtained from the solvent recovery device 20 is cooled and liquefied by a cooler (not shown), The solvent 14 is recovered.

22 is a heating furnace, which is a flammable liquid 21 recovered from the solvent recovery device 20 or an oily substance recovered from the flotation separation tank 11.
12 is used as fuel, hot air 23 obtained by burning these combustions is supplied to the first heat exchanger 24 to heat the heat medium 8 used in the reaction section 5B, and then the hot air 23 is used. Then, the heat medium 8 used in the solvent recovery device 20 is heated by being supplied to the second heat exchanger 25. Reference numeral 26 is exhaust gas, 27 is combustion air, and 28 is combustion ash.

In addition, in the flow shown in FIG. 2, the mixture slurry 9 obtained from the atmosphere opening device 10 is supplied to the flotation / separation tank 11 to selectively collect the oily substance 12 in advance. The mixture slurry 9 obtained from the apparatus 10 may be directly supplied to the extraction tank 13 to extract all the combustible liquid present. Note that oily substance 12
If the recovery step is omitted, the amount of the solvent 14 used increases slightly, and the flammable liquid 21 obtained from the solvent recovery device 20 also contains the oily substance 12 described above.

FIG. 5 is an explanatory view showing the flow of another embodiment of the sludge oilification reaction according to the present invention, and the steps up to the step of recovering the oily substance 12 by the floating separation tank 11 are exactly the same as those in FIG. To do. The mixture slurry 9 from which the oily substance 12 has been removed by the floating separation tank 11 is then sent to a solid-liquid separator 29 such as a centrifuge or the like, where the solid matter 18 in the mixture slurry 9 is removed. The mixed solution 30 from which solids have been removed is subsequently supplied to the extraction device 31, the solvent 14 recovered by the solvent recovery device 20 is added, and the flammable liquid in the mixed solution 30 is extracted. Solid matter as the extraction device 31 used in the flow shown in FIG.
Since 18 is removed by pre-cure, it is more efficient to use the one in which the solvent 14 and the mixed solution 30 are in countercurrent contact with each other.
When using a solvent having a specific gravity greater than 30, as shown in the figure, the solvent 14 is caused to flow downward from above and the mixed solution 30
Is allowed to flow upward from below, and when a solvent having a specific gravity smaller than that of the mixed solution 30 is used, it is advisable to reverse the vertical direction and bring them into countercurrent contact. The extract 19 thus obtained is supplied to the solvent recovery device 20, and the other steps are the same as those in FIG. In the flow shown in FIG. 5, some combustible liquid of the solid material 18 obtained by the solid-liquid separator 29 adheres, so it is preferable to use the solid material 18 as a fuel for the heating furnace 22. Further, as in the case of FIG. 2, the floating separation tank 11 can be omitted.

The flotation separation tank 11, the extraction tank 13, the three-phase separator 16, the solvent recovery device 20, the second heat exchanger 25 shown in FIG. 2 and the flotation separation tank 11, the solid-liquid separator 29 shown in FIG. The extraction device 31, the solvent recovery device 20, the second heat exchanger 25, and the like correspond to devices for recovering the flammable liquid, but it is not necessary to use a combination thereof, and the point is that the mixture slurry 9 is flammable. Any material that can effectively collect the liquid may be used.

The above-mentioned scraping type oilification reactor (Fig. 1) causes a problem such as a clogging problem due to unreacted sludge in the front part of the reactor, which causes a problem. (Part 5B)
Since a scraper is installed on the front side of the machine and a screw mechanism is installed on the front stage (preheating section 5A) of the machine, heat is applied to the dehydrated sludge 3 by this screw mechanism and the dehydrated sludge with poor fluidity is forced to the scraper side. By moving it, troubles such as clogging often seen in the front part of the reactor are effectively eliminated. At the same time, the dehydrated sludge, which moves to the latter part of the reactor and floats heat to improve the fluidity, is efficiently given heat by the scraper to perform thermochemical reaction.
At that time, if a circulation line is provided from the outlet of the rear part of the reactor to the front part of the reactor, the reaction will be completed and some of the reactants that have improved fluidity will be circulated. The effect of is more remarkable. This circulation amount can be controlled by changing the rotation speed of the screw.

〔Example〕

As shown in FIG. 6, jacket pipes J are provided outside the heat exchange type oilification reactor 6, respectively, and a heat medium 8 is introduced into each of them, and a scraper B is provided in the latter half of the inside thereof.
A screw mechanism A is installed in each of the front stages, and heat is applied to the dehydrated sludge charged into the reactor 6 from the inlet C by the screw mechanism A at the inlet C side of the reactor 6, that is, in the reaction front stage. The sludge scraping surface type heat exchanger is effectively operated by the scraper B on the outlet D side of the reactor 6, that is, at the latter stage of the reaction. The rotating shafts of the scraper B and the screw mechanism A serve as a common shaft and project from the front stage of the reactor 6 and are driven by the motor M.

It is desirable that the dewatered sludge in the reactor 6 is heated to about 200 ° C., and that the preheating section 5A equipped with the screw mechanism A and the subsequent section are the reaction section 5B equipped with the scraper B.

FIG. 7 shows the reactor outlet D to the inlet C at the front stage of the reactor 6.
It is the same as the case of FIG. 6 except that a circulation line E which is introduced together with or opposite to is provided.

〔The invention's effect〕

In the sludge oilification reactor of the present invention, by using the screw mechanism as the front stage structure of the scraper installed in the conventional sludge oilification reactor, the screw mechanism prevents clogging by unreacted sludge at the reactor front stage. While avoiding the above, the scraper type heat exchanger as a whole exhibits the characteristics of scraper type heat exchangers, which eliminates the problem of blockage near the inlet of the oilification reactor and is expected to provide stable industrial operation with great industrial value. There is something.

[Brief description of drawings]

FIG. 1 is an explanatory view of a conventionally known scraped surface heat exchange type oilification reactor, FIG. 2 is an explanatory view showing a flow of sludge oilification reaction using the oilification reactor, and FIG. 3 is FIG. 4 is an explanatory view showing a flow of the press-fitting device in FIG. 4, FIG. 4 is an explanatory view showing a flow of the atmosphere opening device in FIG. 2, FIG. 5 is a flow explanatory view showing a device different from FIG. 2, and FIG. FIG. 7 and FIG. 7 are explanatory views of a scraped surface heat exchange type oilification reactor provided with a screw mechanism showing each embodiment of the present invention. 6 ... Oilification reactor A ... Screw mechanism B ... Scraper E ... Sludge circulation line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Nakamura Inventor Hideo Nakamura 5-5-16 Hongo, Bunkyo-ku, Tokyo Within Organo Co., Ltd. (56) References JP 62-136299 (JP, A) Special Table Sho 61 -500654 (JP, A)

Claims (2)

[Claims] 1. A heat exchange type oilification reactor in a sludge oiling apparatus for thermochemically reacting an organic sludge under high temperature and high pressure conditions to obtain a flammable liquid from the sludge and treating the sludge. The sludge oil conversion reactor is equipped with a scraper in the rear part of the inside and a screw mechanism in the front part. 2. The sludge oil conversion reactor according to claim 1, wherein a circulation line is provided from the reactor outlet to the inlet.