JPS6354970B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for drying and incinerating water-containing organic matter, which is equipped with an indirect heating dryer and power generation equipment.

Conventionally, sludge, which is a water-containing organic material with a water content of 60 to 90%, has been treated using equipment such as a vertical multi-stage rotary kiln that has a drying section and an incineration section. In other words, the input wet cake is dried by contacting with the high temperature gas generated when the cake is incinerated, and this dry cake is sent to the incineration section where it is burned naturally or with auxiliary fuel. It is being This system has the drawback that, since the exhaust gas temperature is as high as the present invention, a large amount of heat is required to evaporate the moisture in the wet cake and raise the temperature to this temperature. In addition, when processing with a fluidized bed combustion equipment, there is no distinction between the drying section and the incineration section, so the exhaust gas temperature becomes even higher, making it essential from an economic point of view to install an appropriate exhaust gas heat recovery device. .

The present invention fundamentally solves these conventional difficulties, and its basic idea is to distinguish the drying section from the incineration section, and to remove as much moisture as possible from hydrated organic matter in the dryer. The condensation temperature of the exhaust gas is increased by using an indirect heating dryer to avoid condensable components, and at the same time, the superheated steam is circulated and reused to avoid contamination with non-condensable gases. According to the exhaust gas, if heat is exchanged with a working fluid that evaporates at high pressure at the temperature of the exhaust gas through a heat exchanger, power generation can be sufficiently achieved using this working fluid. In addition, dried organic matter is supplied to an incinerator and incinerated, but when targeting sludge, the calorific value of dried sludge is small, but it can be treated as a solid fuel like coal. Therefore, it is possible to use equipment with a high heat capacity per unit volume, such as a pulverized coal combustion furnace or a fluidized boiler.
Inexpensive equipment is sufficient, and sufficient heat recovery can be performed. This is based on the knowledge that if heat is recovered in this type of equipment and the supplied wet sludge is dried using the recovered heat, the heat can be used effectively.

Hereinafter, the present invention will first be explained using specific examples shown in the drawings, and then individual characteristics will be described.

The following discussion will focus on sludge treatment, but
Of course, the present invention can also be applied to hydrated lignite, bagasse, etc. as the hydrated organic matter. In the drawing, reference numeral 1 is an indirect heating dryer, and the figure shows an example of the cloak 2.
A stirring type dryer is shown, which is equipped with a large number of stirring blades 3 inside. The wet sludge S is supplied by a feeder (not shown), dried through the peripheral wall by the heat medium passing through the jacket 2, and the dried sludge is led to the incinerator 5 through the supply path 4. A portion of the dried sludge is discharged out of the system via the discharge path 4'. During drying, the sludge is stirred by the stirring blades 3 to ensure contact with the heat of the heating medium. In the incinerator 5, combustion air A is blown into the air inlet 6 at the lower part of the incinerator 5 and blown out from the grate 7, thereby incinerating the sludge. The dust D is discharged through the discharge port 8.

On the other hand, the exhaust gas containing moisture from the dryer 1 is discharged from the outlet 9 and passes through the pipe 10 to the exhaust fan 11 and the heat exchanger 12. heat exchanger 1
2 is provided with a circulation path 13 through which a working fluid such as Freon R-114 passes. In this heat exchanger 12,
Exhaust gas guided through the pipe 10 enters the inlet 12a.
It enters, condenses, and is discharged from the outlet 12b. At this time, the condensed working fluid flowing in from the inlet 12c is evaporated and discharged from the outlet 12d, reaching the turbine 15 connected to the generator 14. After rotating the generator 14 by the rotational force during expansion, the condenser 16, and is circulated again to the heat exchanger 12 by a pressure pump 17.

Further, a part of the exhaust gas from the dryer 1 is guided by the exhaust fan 11 to the gas heater 18, where it is heated by a heat medium described below, and then supplied into the dryer 1 through a pipe 19. , has become cyclical.

On the other hand, a heat medium is supplied to the dryer 1 via a pipe line 20, and after drying the wet sludge, it is sent to the incinerator 5 via a pipe line 21. A heat transfer heat recovery section 22 is provided in the incinerator 5, and the heat medium is transferred to the heat recovery section 22.
After absorbing the generated heat in the incinerator 5, it exits from the outlet 23, and flows through the pipe 24, the valve 28, and the pipe 25.
and further through lines 20 and 26, a portion is recycled to the dryer 1 and another portion is sent to the gas heater 18 for heating. gas heater 18
The waste heat medium is returned to the heat recovery section 22 again through the pipe 27.

Furthermore, when the heat medium is water vapor, the heat recovery section 2
After being made into superheated steam in step 2, the valve 28 is closed;
The valves 29 and 30 open, and the superheated steam flows into the generator 31.
After the gas is supplied to the turbine 32 connected to the turbine 32 to generate electricity, it is sent through the pipe 33 to the dryer 1 and the gas heater 18 in the same manner as in the above example. In addition,
Since the amount of heat generated in the incinerator 5 and the energy required by the dryer 1 etc. are not balanced, a portion is used for power generation by the working fluid passing through the heat exchanger 12, or is used for other purposes through the pipe 34. Can be used.

According to the sludge incineration apparatus described above, since the indirect heating dryer 1 is used for drying, the amount of non-condensable gas passing through the dryer 1 is compared with the evaporated water from the condensed sludge. In some cases, use heated steam without non-condensable gases,
By keeping the condensation temperature of the evaporated water as high as possible, a working fluid that evaporates at high pressure at this temperature can be obtained. As a result, sufficient power can be generated based on this working fluid. In addition, the gas heater 18
The drying efficiency can be increased by heating with the high-temperature heating medium passing through the heat recovery section 22.

Further, as mentioned above, since dry sludge with low moisture content is supplied to the incinerator 5, heat recovery can be easily performed using inexpensive equipment. Oil, steam, etc. can be used as the heating medium, but especially in the case of the latter steam, the incinerator 5 can be operated at a high enough temperature to turn it into superheated steam. The obtained superheated steam allows the turbine 32 to generate electricity. Here, the exhaust gas temperature of the turbine 32 is low, approximately 100 to 140°C. Even if a direct heating type dryer is adopted and the exhaust air from the turbine is used to heat the drying air, a high heating air temperature cannot be obtained, making it difficult to dry sludge with a high moisture content. Not only does it require a large amount of air, but it also has poor thermal efficiency. Fortunately, however, water vapor has a low temperature but a large amount of sensible heat, and if this is led to an indirect heating type dryer, a thermal efficiency of about 90% can be achieved.

Note that the treatment equipment of the above example does not require a deodorizing device required for conventional sludge drying. In other words, in this equipment, what is discharged outside the system is mainly condensed water and only a small amount of non-condensable gas is present, so the cost for countermeasures against bad odors is extremely small.

By the way, although a stirring type dryer is shown as an example, any indirect heating type dryer such as a steam tube dryer or a fluidized bed type with a heater may be used. In addition, as a working fluid, Freon R-
In addition to 114, ammonia and the like can be used. Furthermore, when a high boiling point organic heat medium is used as a heat medium, power is not generated, but the high temperature heat medium can be used directly for indirect heating, which increases the temperature difference for heat transfer and makes the dryer smaller. It can be done.

As described above, according to the present invention, it is possible to effectively utilize the heat of drying and incineration of water-containing organic matter to generate electricity with high heat generation efficiency. By configuring the main heat medium circulation system that returns to the dryer through the heat recovery section, the heat medium can be heated to a high temperature in the heat recovery section, resulting in high drying efficiency, and further branched from the main heat circulation system to the gas heater. We have also installed an auxiliary heating medium circulation system that returns to the heat recovery section through the gas heater, so that the steam generated from the dryer can be reliably superheated and vaporized when returned to the dryer.
Drying efficiency can be increased. The advantage is thus that the thermal efficiency of the entire process is extremely high.

Next, examples will be shown.

Example This example is almost the same as the flow shown in the drawing.
An indirect heating dryer having a diameter of 1200 mm x a length of 6000 mm, an effective heat transfer area of 20 m ² and 120 stirring blades inside was operated at a rotation speed of 150 RPM. Pulp sludge with a water content of 75% and a calorific value of 4000 Kcal per dry solid was supplied to this dryer at a rate of 600 Kg/hr, and steam at 5.0 Kg/cm ² ·Gage was supplied to the mantle. The superheated steam from the dryer has a temperature
At 130°C, this was introduced into a heat exchanger at a rate of about 1400 kg/hr, where heat was exchanged with Freon R-114 as a working fluid, yielding condensed water at a rate of 400 to 420 kg/hr. The evaporation temperature of Freon R-114 is 80℃, and the pressure is 9.3Kg/ ^cm2 .
It was absolute pressure. This evaporative working fluid is supplied to a small expansion turbine and expanded to 3.2Kg/ ^cm2 .
After generating 20.5kw of electricity, it was supplied to a condenser with a condensation temperature of 45℃, and the condensed water was returned to the heat exchanger. On the other hand, the dried sludge with a moisture content of 15% is supplied to a fluidized bed incinerator with an inner diameter of 1200 mmφ and a height of 4000 mm. Preheated air at 200°C is supplied from the bottom of the incinerator, and the temperature inside the furnace is 900°C. and 2300Nm ³ /
hr hot air was obtained. This hot air is supplied to the waste heat boiler, which produces 900% steam at a temperature of 250℃ and a pressure of 30Kg/ ^cm2.
Obtained at the rate of Kg/hr. This steam is 6Kg/ ^cm2・
After being depressurized in the gage, it was supplied to the dryer at a rate of 250 Kg/hr and to the heater at a rate of 80 Kg/hr, and the remaining steam was depressurized.

As is clear from this example, it would be better if the target sludge could self-combust in the conventional example, and it was not possible to obtain electricity or even surplus steam, but it was possible to generate electricity and , sufficient heat can be recovered from the heating steam of the dryer.
This is because the sludge was dried by indirect heating, and superheated steam was used as the vapor generated at the same time, and was taken out of the dryer system without using other non-condensable gases, so the condensation temperature in the heat exchanger was This is due to the fact that the temperature excluding the degree of superheating is the steam condensation temperature (100°C) under atmospheric pressure, and as a result, the evaporation temperature of the working fluid becomes high, which increases the power generation efficiency.

In addition, in the example, the high-pressure steam was released as it was because the plant was relatively small-scale, but as mentioned above, if a large amount of steam can be obtained industrially, it is possible to generate electricity using a turbine. .

[Brief explanation of the drawing]

The drawing is a flow sheet showing a specific example of the present invention. 1...Indirect heating dryer, 5...Incinerator, 12...Heat exchanger, 15...Turbine, 16...Condenser, 1
8... Gas heater, 22... Heat recovery section.

Claims (1)

[Claims] 1. After drying the hydrated organic matter using a heating medium in an indirect heating dryer, the steam generated by this drying is used as a driving source for a power generation turbine, and
In a drying and incineration apparatus configured to supply dried organic matter to an incinerator after drying: a main heating medium circulation system that recirculates a heating medium from the dryer to the dryer through a heat recovery section in the incinerator;
A working fluid power generation system in which the steam generated from the dryer is guided to a heat exchanger and condensed there, while the working fluid of the power generation turbine is brought into indirect contact with the heat exchanger; a steam circulation system in which a portion of the heat medium circulation system is returned to the dryer via the gas heater; the main heating medium circulation system is branched off at the exit side of the heat recovery section, passes through the gas heater, and there gives heat to the steam passing through the steam circulation system; An auxiliary heat medium circulation system that returns to the inlet side of the heat recovery section; 2 The heating heat medium is steam, and the heat medium after heat recovery is supplied to the power generation turbine and then recirculated to the dryer.
Drying and incineration equipment for water-containing organic matter as described in 2. 3. An apparatus for drying and incinerating water-containing organic matter according to claim 1, wherein the steam from the drying is circulated through a gas heater as superheated steam as much as possible to the dryer.