JPS6023719B2 - How to use pyrolysis drain - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of utilizing condensate generated when solid waste is pyrolyzed to produce gas.

Solid waste such as municipal waste undergoes various processes to recover resources and energy, and one of these processes is the recovery of gas, oil, and char produced by pyrolysis. .

The oil recovered at this time is usually further refined and used, for example, as fuel. On the other hand, in the case of a single-type pyrolysis device with only a decomposition tower, auxiliary fuel for combustion is required, and in the case of a system that has a decomposition tower and a combustion tower and circulates the heat medium, auxiliary fuel is required for heating and regenerating the heat medium. However, it requires
These auxiliary fuels were supposed to be supplied by a separately provided fuel supply station, and for this purpose, fuel and V supply stations were particularly required.

In addition, it takes time and effort to adjust the expected amount of fuel, and if the adjustment is insufficient, the thermal decomposition temperature becomes unstable, resulting in fluctuations in the quality and quantity of the produced gas.

The present invention eliminates the above-mentioned drawbacks of the conventional methods, does not particularly require auxiliary fuel for heating and regenerating the heat medium, suppresses fluctuations in the pyrolysis temperature, and achieves stable pyrolysis operation. The purpose of the present invention is to provide a method of utilizing a pyrolysis drain that can perform the following steps. In order to achieve this objective, the inventors conducted repeated research and experiments, and based on the knowledge obtained during the research, the present invention was made.

In other words, through many experiments, the inventors found that ``the amount of recovered seed oil at high temperatures during pyrolysis decreases;
Based on this knowledge, the invention of the present invention is to ``burn the oil obtained from the generated gas in a combustion tower and use it to heat the heat medium.''
We came up with this technical idea.

Therefore, we have arrived at the configuration of the present invention as a means to embody this technical idea.

By adopting such a configuration, when the pyrolysis temperature increases or decreases as described below, the recovered oil base decreases or increases in response, and the pyrolysis temperature decreases in the direction of returning to the reference temperature. Alternatively, the thermal decomposition temperature can be increased, and stable thermal decomposition can be performed by such self-control of the thermal decomposition temperature.

The present invention provides a method for utilizing a pyrolysis drain in a pyrolysis process of solid waste, in which a heat medium such as sand is circulated between a pyrolysis tower and a combustion tower. The pyrolysis gas is cooled by cooling*,
The generated drain is collected into a drain tank provided at the lower end of the cooling tower, and then oil and moisture are scaled, and the obtained oil is burned in the combustion tower and used for heating the heat medium. This is a method of using pyrolysis drain characterized by the following. To illustrate the present invention with reference to the drawings, in FIG. 1, 1 is a two-column type thermal cracking system having a cracking tower 2 and a combustion tower 3.

A heat medium such as sand is circulated between the two banks by the connecting pipes 4 and 5, the tin feed device 6, and the tin feed pipe 7, and in the cracking tower 2, the fluidized gas blown from the fluidized gas supply pipe 8 is passed through the perforated plate 9. It is designed to blow the heat medium upward and form a fluidized bed. Solid waste, which is also a raw material for thermal decomposition, is put into a hopper 10 and fed into a cracking tower 2 by a feeder 11. 12 is an air nozzle for feeding tin.

13 is a drain separator having cyclones 14, 15, a heat exchanger 16, a cooling tower 17, and a demister 18.

A drain tank 19 is provided at the bottom of the cooling tower 17 as a drain recovery device. 20 is a neutralization tank for adjusting pH.

21 is an oil recovery device, which includes a drain storage tank 22 and an oil/water separator 2.
3. It has an oil storage tank 24.

The drain storage tank 22 has an oil floating chamber 25, a moisture chamber 26, and a residue chamber 2.
7, and the oil floating chamber 25 and the moisture chamber 26 are separated by a partition wall 28.
The lower part is suitable for mulberry. 29 is a floating oil extractor.

The pump 30, pipes 31 and 32, and valves 33 and 34 form a recovered oil supply device. Line 31 is the combustion zone of pyrolysis device 1 . A line 32 connects to the combustion tower 3 and the cracking tower 2 . On the other hand, in order to treat the waste gas generated in the combustion tower 3, a cyclone 35, a heat exchanger 36, a cooling tower 37
, a drain tank 38, and a neutralization tank 39. 4
0 is a waste liquid treatment device that processes waste liquid from the oil/water separator 23 and the neutralization layer 39, and discharges waste water 41 and precipitated solid content 42.

When operating a device constructed as described above,
The solid waste supplied to the decomposition tower 2 via the hopper 10 and feeder 11 is thermally decomposed in a heat medium forming a fluidized bed, and the generated gas is separated from solids by cyclones 14 and 15, and then transferred to a heat exchanger. At 16, the fluidized gas going to the fluidized gas supply pipe 8 is preheated to 0, cooled and condensed by the cooler 17, and then entered into the drain tank 19 to separate the drain.The gas is removed from dust by the demister 18 and then sent to the process.

The drain remaining in the drain tank 19 is equivalent to floating tar.
It is roughly divided into water-soluble organic content and precipitated solid content. Dotalene is first subjected to pH adjustment in a neutralization layer 20 and sent to a drain storage tank 22. The drain storage tank 22 is divided into three parts, and the drain first enters the first oil floating chamber 25. Here, floating oil is removed. The water chamber 26 is connected to the oil floating chamber 25 at the lower part of the storage tank, and the water level is maintained at a constant zero level. Floating tar is not mixed in the drain that enters the moisture chamber 26. Further, the precipitated solid content accumulates in the residual bamboo chamber 27. The drain from which floating tar and precipitated solids have been removed is separated into oil and other substances by an oil-water separator 23, and the oil is stored in an oil storage tank 24. The floating tar collected by the floating oil collector 29 is also stored in the oil storage tank 24. Other substances are treated by the waste liquid treatment device 40 and discharged after reducing harmful components to below a standard value.
The drain oil stored in the oil storage tank 24 is sent to either the trowel decomposition tower 2 or the combustion tower 3 by the pump 30' and is decomposed or combusted. Whether it is blown into either the decomposition or combustion tower is determined by operating the valves 33 and 34. o The drain from the cooling tower 37 is adjusted to pH 7-8 in the neutralization tank 39, and at the same time, the solid content is silently separated. The waste liquid is then processed by a waste liquid processing equipment 40,
It is discharged after reducing harmful components to below standard values.

Since the oil thus recovered can be used as an auxiliary fuel for the pyrolysis process, no separate fuel is required.

The oil content in the drain collected in the cooling tower 17 is 9000~1
Since it has a calorific value of 000 cal/kg, it is possible to obtain a considerable amount of heat by using this. There are two ways to effectively use this within the device itself: sending it to the combustion tower 3 for combustion, and sending it to the decomposition tower 2 for thermal decomposition.
When sent to the combustion tower 3, the oil is combusted and the temperature of the heat medium is increased, and when sent to the cracking tower 2, the oil is thermally decomposed and gasified. First, the case where the recovered oil is burned in the combustion tower 3 will be explained. The amount of condensate (oil, char, water) generated by pyrolysis changes depending on the pyrolysis temperature (it decreases when the pyrolysis temperature is high), but the amount of oil in particular decreases when the pyrolysis temperature is high; If the amount is low, the tendency to increase is significant. For example, when the thermal decomposition temperature is high, the amount of recovered oil is small, the amount of oil returned to the combustion chamber 3 which is the combustion zone and burned is also small, and the amount of heat given to the heat medium is also small. The thermal decomposition temperature is therefore lowered. Conversely, if the thermal decomposition temperature is low, the thermal decomposition temperature will be increased.

In this way, the thermal decomposition temperature is self-determined, thermal decomposition is carried out at a stable temperature, and the quality and quantity of the produced gas are stabilized. In other words, the thermal decomposition temperature of solid waste has a wide temperature range, and thermal decomposition is possible within the range of about 600 to 800 pm, and waste with a low calorific value can be thermally decomposed in a low temperature range. However, in the case of waste with a high calorific value, thermal decomposition is carried out in a high temperature range. Therefore, when thermally decomposing solid waste, when the recovered oil is burned in a combustion tower to heat the heating medium, the amount of heat commensurate with the amount of recovered oil depends on the type and composition of the solid waste. The decomposition temperature is determined as a reference temperature, and thermal decomposition is performed at this reference temperature.

Under such operating conditions, if there is a fluctuation in the pyrolysis temperature, the pyrolysis temperature will be returned to the reference temperature in the opposite direction of the fluctuation, depending on the relationship between the pyrolysis temperature and the amount of recovered oil as described above. It acts to bring about change.

That is, as the temperature decreases, the amount of recovered oil increases and the amount of heating of the heat medium increases, which acts in the direction of returning the pyrolysis temperature to the reference temperature.
When the temperature rises, the amount of recovered oil decreases, the amount of heating of the heat medium decreases, and this acts in the direction of returning the pyrolysis temperature to the reference temperature. In other words, when there is a fluctuation in the pyrolysis temperature, an action to suppress the fluctuation, that is, a self-control action of the pyrolysis temperature is generated, so that the temperature may further fluctuate in the same direction and reach the maximum or minimum allowable value. This not only prevents the pyrolysis operation from exceeding the limit and causing problems, but also stabilizes the quality and quantity of the pyrolysis gas produced. Furthermore, when decomposing in the decomposition column 2, the amount of gas is increased and harmful components are concentrated in the drain, which is advantageous for economy and pollution control. It is also possible to switch between these two methods with a valve to improve stability and economy by using different methods depending on the operating situation.

That is, when the operating temperature in the combustion tower 3 is maintained within a predetermined range and there is still an excess of oil, it is desirable to combine this remaining oil into the pyrolysis tower 2 and subject it to pyrolysis treatment.

If fractional distillation is performed during drain recovery, the resulting oil can be classified and the water and oil can be easily separated.

That is, as shown in FIG. 2, the drain separation Hishitaka 13 has a heat exchanger 16, a first cooling tower 43, a second cooling tower 44, a third cooling tower 45, and a demister 18, and a drain tank as a drain recovery device. 46, 47, 48, 49. heat exchanger 1
The decomposed gas exiting from 6 enters the first cooling tower 43 at high temperature. 1st
When the outlet temperature of the cooled 43 is adjusted to 150°C, high boiling point components in the drain condensed in the first cooling tower 43 are collected in the drain tank 47, and the outlet temperature of the second cooling tower 44 is adjusted to 150°C.
If the temperature is slightly higher than 1000C to 105 qo, components with intermediate boiling points are collected in the drain tank 48. The outlet temperature of the third cooling tower 45 is set to room temperature, and the low boiling point components are condensed here, and water and the low boiling point components are collected in the drain tank 49. The medium and high boiling point components collected in the drain tanks 48 and 47 do not contain much water and can be directly combusted. Since the low boiling point components collected in the drain tank 49 are insoluble in water, they can be easily separated. The separated low boiling point components must be in a state where they can be directly combusted. In the case of the above example, most of the water in the drain condenses in the third stage (about 70 to 90% of the total drain). According to some embodiments, the calorific value of each oil is high boiling point oil 87
8 has al/evening, medium boiling point oil is 9 spots, al nota is low boiling point oil is 97
1 has been shown to be useful in obtaining high values such as al/e. The amount of oil was recovered at a ratio of high: medium: low of approximately 1:2:10. 0 Note that when the outlet gas temperature of the heat exchanger 16 is low, high boiling point components can be collected using a tar trap, and the first cooling tower 43 and drain tank 47
is not used.

According to the present invention, since the recovered oil can be used as auxiliary fuel, not only is no other fuel required, but the thermal decomposition is carried out at a standard temperature commensurate with the amount recovered depending on the type and composition of solid waste. Even if the pyrolysis temperature increases or decreases, the amount of recovered oil increases or decreases in the opposite direction to the temperature increase or decrease, so a self-control action is performed to suppress the pyrolysis temperature in the direction of returning it to the reference temperature. , we provide a method for using pyrolysis drains that not only does not cause the pyrolysis temperature to exceed the upper or lower limits of the allowable temperature and thereby impede the pyrolysis operation, but also stabilizes the quality and quantity of the produced gas. can,
This has extremely great effects in terms of practical use, resource recovery, and energy recovery.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall flow sheet, and FIG. 2 is a flow sheet of a fractional drain separation device. 1... Pyrolysis device 2... Decomposition tower, 3... Combustion tower, 4, 5... Connecting pipe, 6... Tin feeding device, 7...
Yang feed pipe, 8... Fluidizing gas supply pipe, 9... Perforated plate, 10-hopper, 11... Feeder, 12... Nozzle, 13... Drain separation device, 14, 15... Cyclone, 16... Heat exchanger , 17... Cooling tower, 18... Demister, 19
... Drain tank, 20... Neutralization tank, 21... Oil recovery device, 22... Drain storage tank, 23... Oil/water machine, 24... Oil storage tank, 25... Oil floating Room, 26・
...Moisture chamber, 27...Residue chamber, 28...Partition wall, 29
...Floating oil extractor, 30...Pump, 31, 32...Pipe line, 33, 34...Valve, 35...Cyclone, 36...
・Heat exchanger, 37... Cooling tower, 38... Drain tank, 39... Neutralization tank, 40... Waste liquid treatment device, 41
...Drainage water, 42... Precipitated solid content, 43... First cooling tower, 44... Second cooling tower, 45... Third cooling tower, 46
, 47, 48, 49... Drain tank. Figure 1 Figure 2

Claims (1)

[Claims] 1. In a method of using a pyrolysis drain in a pyrolysis process of solid waste in which a heat medium such as sand is circulated between a pyrolysis tower and a combustion tower, a cooling tower installed in a flow path for pyrolysis gas. The pyrolysis gas is cooled by the cooling tower, and the generated drain is collected in a drain tank installed at the lower end of the cooling tower. After that, oil and water are separated, and the obtained oil is combusted in the combustion tower. , A method of using a pyrolysis drain, characterized in that it is used for heating the heating body.