JP2000279791A - Operation of supercritical water reaction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for smoothly starting and operating a supercritical water reaction device at the time of treating plural liquids to be treated having different calorific value per unit volume from each other with supercritical water. SOLUTION: At the time of starting up the supercritical water reaction device, a compressor 28 is driven to feed air to a reactor 12 to increase the pressure of the reactor to a prescribed pressure. Next, the supercritical water flows in while feeding air and the temp. of the reactor is increased to 390 deg.C. The liquid A to be treated having low oxidation calorific value per unit volume is introduced into the reactor with a pump 24A for liquid to be treated driven while passing the super-critical water to start the oxidation reaction. Next, the liquid B to be treated having higher oxidation calorific value per unit volume than the liquid A to be treated is supplied to the reactor in addition to the liquid A to be treated or by being switched from the liquid A to be treated to continue the supercritical water reaction and when the temp. of the reactor reaches 500-550 deg.C, the feed of the supercritical water is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a supercritical water reactor, and more particularly, to a method for operating a supercritical water reactor to generate a plurality of types of treated materials having different heating values for oxidation per unit volume. The present invention relates to a method for starting a supercritical water reactor smoothly and operating it stably when a liquid is simultaneously introduced into a reactor and a supercritical water reaction is performed in the presence of supercritical water.

[0002]

2. Description of the Related Art With increasing awareness of environmental issues,
Attention has been paid to attempts to decompose and detoxify environmental pollutants by utilizing supercritical water reaction, which has high ability to oxidize and decompose organic substances. That is, harmful and hardly decomposable organic substances, such as PCB (polychlorinated biphenyl), dioxin, and organic chlorinated compounds, which were difficult to decompose in the related art by supercritical water reaction utilizing high reactivity of supercritical water. It is an attempt to decompose a solvent or the like and convert it into harmless products such as carbon dioxide, nitrogen, water, and inorganic salts.

[0003] A supercritical water reactor is a device that decomposes organic substances by using high reactivity of supercritical water. For example, harmful organic substances that are hardly decomposable are decomposed and harmless carbon dioxide and water are decomposed. In order to convert the hard-to-decompose high-molecular compounds into useful low-molecular compounds,
Its practical application is being actively studied. Supercritical water refers to water that is in a supercritical state, that is, water that is in a state beyond the critical point of water, and specifically, at a temperature of 374.1 ° C. or more and a pressure of 22.04 MPa or more. A state of water. Supercritical water has a high ability to dissolve organic substances and can completely dissolve non-polar substances, which are abundant in organic compounds, but has a very low ability to dissolve inorganic substances such as metals and salts. The supercritical water can be mixed with a gas such as oxygen or nitrogen at an arbitrary ratio to form a single phase.

Here, the basic configuration of the supercritical water reactor will be described with reference to FIG. FIG. 3 is a flow sheet showing the basic configuration of the supercritical water reactor. The supercritical water reactor 10 is a device for treating a liquid to be treated containing harmful organic substances by a supercritical water reaction in the presence of supercritical water, and as shown in FIG. A vertical pressure-resistant closed type reactor 12 is provided as a vessel, and a processing solution pipe 14 through which a processing solution flows out of the reactor 12 is sequentially cooled by a cooler 16 for cooling the processing solution, and the pressure in the reactor 12 is controlled. The apparatus includes a pressure control valve 18 and a gas-liquid separator 20 that separates the processing liquid into gas and liquid. The vertical reaction vessel is usually suitable for treating a liquid to be treated having a low solid content, and when treating a liquid to be treated having a high solid content, a pipe-shaped tube is generally used. Often, a reactor is used.

[0005] The supercritical water reactor 10 has a supply system for supplying a reactant to be used for the supercritical water reaction to the reactor 12.
The reactor 12 includes a liquid to be treated pump 24 and an air compressor 28, and supplies a liquid to be treated containing an organic substance to the reactor 12
And the air as an oxidant is sent into the reactor 12 together with the liquid to be treated via the air supply pipe 26 and the liquid pipe 22 to be treated.

[0006] Further, the supercritical water reactor 10 is provided with an auxiliary fuel for feeding an auxiliary fuel to the reactor 12 as necessary as a heat energy source for maintaining the supercritical water reaction in the reactor 12. A tube (not shown) and an alkali agent feed tube (not shown) for feeding an alkali agent for neutralizing chlorine and the like generated from organic substances in the processing solution by the supercritical water reaction in the reactor 12 to the reactor 12. ) Is joined to the liquid pipe 22 to be treated.

A heat exchanger (not shown) for exchanging heat between the liquid to be processed and the processing liquid to cool the processing liquid and raise the temperature of the liquid to be processed to recover heat is provided upstream of the cooler 16. A preheater for preheating the liquid to be treated is provided in the reactor 12
May be provided in the liquid pipe 22 to be processed, which is located upstream of the pipe. Also, a supercritical water supply water pipe may be connected to the liquid pipe 22 to be treated. Further, a subcritical water region is provided at the lower part of the reactor 12,
A mechanism may be provided to settle and remove inorganic salts generated in the reactor 12 in the subcritical water region.

[0008]

By the way, the excellent point and effect of the organic matter treatment by the supercritical water reaction are evaluated and, for example, a supercritical water reactor is installed at the source of the liquid to be treated, and the unit volume is increased. A plurality of liquids to be treated, each containing a different kind of organic matter having a different calorific value per unit, are simultaneously treated in a supercritical water reactor.

For example, as shown in FIG. 2, in a supercritical water reactor 30 for treating two kinds of liquids to be treated, two treatment liquid pumps 24A and B are provided, and The liquid pump 24A is connected to the reactor 12, and a liquid pipe 22B to be connected to the liquid pipe 22 is provided.
2B and the liquid pump 22B through the liquid pipe 22
And the reactor 12 are connected. The processing liquid A and the processing liquid B are often simultaneously processed by the processing liquid pumps 24A and 24B.

However, in order to treat the liquid to be treated A and the liquid to be treated B with supercritical water, the liquid to be treated A and the liquid to be treated B are supplied to the reactor when the supercritical water reactor is started and during normal operation. When the liquid is sent, there has been a problem that the temperature of the reactor fluctuates, and particularly the temperature of the reactor rises, and it is difficult to stably perform the treatment.

Accordingly, an object of the present invention is to provide a supercritical water reactor that can smoothly start a supercritical water reactor when a plurality of types of treatments having different calorific values per unit volume are subjected to supercritical water treatment, especially at the time of startup. And provide a way to drive.

[0012]

The inventor of the present invention has proposed that a plurality of kinds of liquids containing different kinds of organic substances, such as the liquids A and B to be treated as described above, are fed into a reactor, When the water reactor was started and operated, the cause of the sudden rise in the temperature of the reactor and the fluctuation of the pressure conditions were investigated, and the following was found. Normally, when the liquid to be treated is fed into the supercritical water reactor, the concentration of the organic substance in the liquid to be treated, more specifically, the amount of heat generated by the oxidation of the organic substance per unit volume of the liquid to be treated is substantially constant. The liquid to be treated A and the liquid to be treated B are mixed and adjusted before being fed into the reactor.

By the way, for example, a liquid B having a high organic substance concentration, ie, a liquid B having a high oxidative heat generation per unit volume is supplied, and then a liquid A having a low organic substance concentration is supplied.
That is, when the liquid A having a low calorific value of oxidation per unit volume is fed into the reactor, the liquid A to be treated apparently fills the liquid B to be treated filled in the pipe from the mixing section to the reactor. Since the flow rate is also added, a large amount of the liquid to be treated B flows into the reactor. As a result, it has been found that the calorific value per unit time increases in the reactor and the temperature of the reactor rises.

Therefore, a plurality of kinds of liquids to be treated containing different kinds of organic substances as described above at different concentrations, that is, a plurality of kinds of liquids having different heating values of oxidation per unit volume, for example, a first liquid to be treated. When starting the supercritical water reactor for treating the second liquid to be treated, first, the first liquid to be treated, which has a low calorific value of oxidation per unit volume, is fed into the reactor and brought into a steady state. Then, in addition to the first liquid to be treated, the second liquid to be treated having a high oxidative heat generation per unit volume is fed to avoid the above-mentioned problem, and the end of the research Thus, the present invention has been completed.

During the operation of the supercritical water reactor, the first
When the second liquid to be treated is fed into the reactor in addition to the liquid to be treated, the amount of heat generated by oxidation per unit volume of the liquid to be treated is 2 in order to avoid the above-mentioned problem. The inventors thought that it is necessary to be higher than the calorific value of oxidation per unit volume of the first liquid to be treated, and completed the method of the present invention after research.

In order to achieve the above object, based on the above findings, the method for operating a supercritical water reactor according to the present invention provides a method for simultaneously treating a plurality of types of liquids having different heating values of oxidation per unit volume. A method for operating a supercritical water reactor for introducing into a reactor and performing a supercritical water reaction in the presence of supercritical water,
When starting the supercritical water reactor, the first step of feeding air to raise the pressure of the reactor to a predetermined pressure, and, while continuing to feed air, supercritical water is fed into the reactor. A second step of flowing and raising the temperature in the reactor to a first predetermined temperature; and introducing the first liquid to be treated into the reactor while continuing the inflow of the supercritical water, thereby performing an oxidation reaction. A fourth step of supplying, to the reactor, a second processing liquid having a higher calorific value of oxidation per unit volume than the first processing liquid in addition to the first processing liquid. And a fifth step of stopping the inflow of supercritical water when the temperature of the reactor reaches the second predetermined temperature.

In the method of the present invention, the first predetermined temperature is usually about 390 ° C. Further, the second predetermined temperature is a temperature condition of the supercritical water reaction, and is from 500 ° C. to 550 ° C.
In the range.

[0018]

Embodiments of the present invention will be described below in detail with reference to FIG. 1 showing an embodiment. Embodiment 1 This embodiment is an example of an embodiment in which the operation method of the supercritical water reactor according to the present invention is applied to the activation of the supercritical water reactor 30. In the present embodiment, first, the air compressor 2
8, the high pressure air is fed into the reactor 12, and the pressure in the reactor 12 is increased to a predetermined pressure. Next, while continuing to supply high-pressure air, supercritical water flows in through the supercritical water line 40, and the temperature in the reactor 12 is raised to a predetermined temperature, for example, 390 ° C. The supercritical water line 40 includes:
A heater 41 such as a heater or a heat exchanger is provided, and the water is heated by the heater 41 to produce supercritical water. While continuing the inflow of the supercritical water, the liquid-to-be-treated pump 24A is started, and the liquid-to-be-processed A having a low calorific value per unit volume of the liquid to be processed is introduced into the reactor 12, and the oxidation reaction is started. To start.

Next, in addition to the liquid to be treated A, the liquid to be treated pump 24B is started to supply the liquid to be treated B having a higher calorific value of oxidation per unit volume than the liquid to be treated A to the reactor. When the temperature of the reactor 12 rises, the inflow amount of the supercritical water is gradually reduced, and the temperature of the reactor 12 becomes 500 ° C. to 550 ° C.
When the temperature reaches a predetermined temperature in the range of ° C., the inflow of the supercritical water is stopped, and the supercritical water reaction is stably continued.

In the present embodiment, the amount of heat generated by oxidation per unit volume of the liquid A to be processed staying in the liquid pipe 22 to be processed is lower than the amount of heat generated by oxidation per unit volume of the liquid B to be processed. The liquid to be treated having a high calorific value of oxidation per unit volume, which is retained in the feed line to the reactor, is extruded into a liquid to be treated having a low calorific value of oxidation per unit volume fed at a high flow rate, It does not occur that the temperature of the reactor 12 rises sharply.

In the present embodiment, the amount of heat generated by oxidation per unit volume of the liquid A to be processed staying in the liquid pipe 22 to be processed is lower than the amount of heat generated by oxidation per unit volume of the liquid B to be processed. The liquid to be treated having a high calorific value of oxidation per unit volume, which is retained in the feed line to the reactor, is extruded into a liquid to be treated having a low calorific value of oxidation per unit volume fed at a high flow rate, No sudden increase in the temperature of the reactor 12 occurs.

[0022]

According to the method of the present invention, in the operation of a supercritical water reactor for treating a plurality of kinds of liquids to be treated having different heating values for oxidation per unit volume, at the time of start-up, first, The first liquid to be treated having a low calorific value of oxidation is fed into the reactor to be in a steady state, and then the first liquid to be treated is added to the liquid to be treated and the calorific value of oxidation per unit volume is higher than that of the first liquid to be treated. 2. The liquid to be treated is fed. Also, switching of the liquid to be treated,
Also in the case of additional feeding, first, the first liquid to be processed is fed, and then the second liquid to be processed, which has a higher heating value per unit volume of oxidation than the first liquid to be processed, is fed. This allows
As in the prior art, the liquid to be treated having a high oxidative heat generation per unit volume, which is retained in the feed line in the reactor, is converted into a liquid to be processed having a low oxidative heat generation per unit volume which is supplied at a high flow rate. As it is not extruded and flows into the reactor in large quantities,
Stable temperature control can be performed without a sharp rise in temperature in the reactor.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing a basic configuration of a supercritical water reactor.

FIG. 2 is a flow sheet showing a configuration of a conventional supercritical water reactor for treating two types of liquids to be treated.

FIG. 3 is a claw sheet showing a configuration of a conventional supercritical water reactor for treating one type of liquid to be treated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Supercritical water reactor 12 Reactor 14 Treatment liquid pipe 16 Cooler 18 Pressure control valve 20 Gas-liquid separator 22 Liquid liquid pipe 22B Liquid liquid pipe 24 Liquid pumps 24A, B Liquid pump 26 Air sending Inlet pipe 28 Air compressor 30 Supercritical water reactor for treating two types of liquids to be treated 40 Supercritical water line 41 Heater

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Osamu Takahashi 1-2-8 Shinsuna, Koto-ku, Tokyo Organo Corporation (72) Inventor Akira Suzuki 1-2-8 Shinsuna, Koto-ku, Tokyo Olgano F term (reference) 4D050 AA01 AB19 BB01 BC01 BC02 BC10 BD02 BD03 BD06 BD08

Claims (1)

[Claims] 1. A method for operating a supercritical water reactor in which a plurality of types of liquids to be treated having different heating values for oxidation per unit volume are simultaneously introduced into a reactor and a supercritical water reaction is performed in the presence of supercritical water. Therefore, when starting the supercritical water reactor, the first step is to introduce air to raise the pressure of the reactor to a predetermined pressure.
And the supercritical water flows into the reactor while continuing the air supply,
A second step of raising the temperature in the reactor to a first predetermined temperature; and introducing the first liquid to be treated into the reactor while continuing the inflow of supercritical water to start an oxidation reaction. A third step, in addition to the first liquid to be treated, a fourth step of supplying a second liquid to be treated having a higher calorific value of oxidation per unit volume than the first liquid to be treated to the reactor; A step of stopping the inflow of supercritical water when the temperature of the reactor reaches the second predetermined temperature.