JP2002338973A - Water recovery system from combustion exhaust gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover hot water from a combustion exhaust gas to reutilize it and to reduce the amount of water to be used in a system for softening a heavy oil with supercritical water and burning them in the mixed state. SOLUTION: In this system for rendering a heavy oil a soft fuel with supercritical water and producing electric power with the obtained modified fuel, the supercritical water from which impurities have been removed is recovered/reutilized as a part of the supercritical water to be used in the above step of forming the soft fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for dissolving heavy oil in supercritical water to lighten the fuel, and for combusting a fuel mixture of the lightened fuel and the supercritical water to recover water contained in the combustion exhaust gas. It is about the system.

[0002]

2. Description of the Related Art A technique for dissolving heavy oil in supercritical water and lightening the heavy oil to convert it into fuel gas or light oil is well known. Japanese Patent Application Laid-Open No. 2000-109850 proposes a technique for reducing the weight of heavy oil with supercritical water to generate high-efficiency power. In this method, the critical point of water (22.1 MPa,
The heavy oil is dissolved in water at a temperature and pressure of 374 ° C. or higher to lighten it. Light oil and supercritical water are decompressed and cooled, and separated into fuel gas, light oil and water in an oil / water separation step.
Thus, heavy oil can be used as fuel gas and light oil can be used as highly efficient power generation fuel. In this method, the water separated in the oil-water separation step contains additives such as alkali and reducing ammonia, cyanide, and hydrogen sulfide, and the water is taken out of the system to treat these compounds. I have to.

On the other hand, there is a system in which heavy oil is lightened with supercritical water and the fuel and water are led to a combustor without being separated. This method does not require the steps of decompression, cooling, and separation of fuel and water, so that there is no energy loss associated with decompression and cooling of the fuel. In addition, since the fuel mixture of heavy oil and water burns, sulfur and trace metals in the fuel are oxidized and easily processed by environmental devices.

[0004]

In a system in which moisture is introduced to a combustor together with fuel, a large amount of water is used. In order to reduce the amount of water used, it is effective to recover hot water from flue gas.

[0005] An object of the present invention is to provide a system in which heavy oil is lightened with supercritical water and burned while mixed, and impurities such as sulfur oxides and metal oxides absorbed in warm water recovered from combustion exhaust gas. Is to provide a system which can be used for separating and removing the oil and returning it to the supercritical water reactor again for lightening heavy oil.

[0006]

That is, the present invention relates to a system for converting heavy oil into light fuel with supercritical water and generating electricity with the obtained reformed fuel.
It is characterized by being recovered and reused as a part of the supercritical water used in the light fuel conversion process.

[0007] One specific example is a cooling step of cooling the flue gas and collecting condensed water, an adjusting step of storing the collected condensed water and adding an alkali or an oxidizing agent, and pressurizing and heating the adjusted condensed water. It comprises a reaction step for supercritical water reaction and a trapping step for separating and removing impurities in the supercritical water from the reaction step.

[0008] In general, a system for supercritically treating heavy oil and achieving high-efficiency power generation with the obtained reformed fuel includes a reforming reaction section for reacting supercritical water with heavy oil, and impurities in heavy oil. Section, a combustor-integrated gas turbine that burns reformed fuel and generates electricity, a heat recovery section for the combustion exhaust gas discharged from the gas turbine, and removes NO _X , SO _X , and dust in the combustion exhaust gas It is composed of an environmental measures department.

In the cooling step, the combustion exhaust gas is cooled by a refrigerant by an indirect cooling method to obtain condensed water. As the refrigerant, seawater, industrial water, cooling tower water, or the like can be used, but it is preferable to use a low-temperature fluid in the system, for example, feedwater for heavy oil, supercritical water, or feedwater supplied to the heat recovery unit.
The temperature in the cooling step is 90 to 50C, preferably 50 to 6C.
It is about 0 ° C.

[0010] cooling process NO _X, SO _X, the flow after the environmental countermeasure for removing dust, i.e. the flue gas is placed in the lowest portion of the temperature, by indirect contact with flue gas and the refrigerant, moisture in the combustion exhaust gas To condense. Placing the cooling step on the downstream of the environmental section, NO _X in the combustion exhaust gas, S
O _X, dust has been removed to an extremely low level, NO _X in the condensed water in the cooling step, the SO _X penetration is small, i.e. the corrosion of the apparatus can be reduced, the wear reduction of pumps due to contamination of dust It is to plan.

The condensed water recovered in the cooling step is sent to an adjusting step. The adjustment process is a tank for storing condensed water, a measuring instrument for measuring the sulfur content (S content) and carbon content (C) in the condensed water, and an addition for supplying alkali (NaOH, KOH) and oxidizing agent (H ₂ O ₂ ). It is composed of devices. Trace amount of S in condensed water
Compounds (sulfate, dithionic acid) are present, and condensed water is heated as it is to high-temperature, high-pressure water to accelerate the corrosion of the material.
Therefore, the S content in the condensed water is measured, and alkali (NaOH, KOH) corresponding to the amount is equimolar or more, preferably 1 mol or more.
Na ₂ SO ₄ , K ₂ SO
Make it ₄ mag. The alkali may theoretically be added in the stoichiometric amount shown in the above reaction formula.
Double supply. The C content was measured, and H ₂ O ₂ was added to the molar amount of C and S (2H ₂ O ₂ = 2H ₂ O + O ₂ , that is, 1 mol of O ₂ means 2 mol of H ₂ O ₂ ). More than 2 times, preferably 2 to 4 times mole is added to convert C content into CO ₂ gas to prevent precipitation of C occurring in the reaction tube during heating and high temperature. The S compound is converted into SO ₂ or SO ₄ and reacted with an alkali metal.

The condensed water from the adjusting step is pressurized with a pump to a pressure higher than the critical pressure of water, preferably to 22 to 25 MPa,
Send to reaction process. The reaction step is constituted by a heat transfer tube installed in the heat recovery unit, and the condensate containing the additive sent into the heat transfer tube is 374 ° C. or higher, preferably 380 to 41 ° C. in the heat transfer tube.
Heated to 0 ° C. to become supercritical water. In addition, the alkali additive reacts with the S component, and becomes Na ₂ SO ₄ by the reaction, and the C component becomes the C component.
It becomes O ₂ . Since these compounds are present in a state of being dissolved in supercritical water, the temperature in the heat transfer tube is 374 to 410 ° C.
To keep. The supercritical water reacted in the reaction step is sent to the next trapping step.

[0013] The trapping step comprises a trapping tube which is openly connected to the heat transfer tube. The trapping tube is filled with limestone (CaCO ₃ ), dolomite (a substance composed of MgO, CaCO ₃ ), etc., and the temperature of the trapping tube is set at least higher than the temperature of the reaction step, preferably 410 ° C. to 500 ° C. In the trapping tube, the filled limestone and supercritical water in which the impurities are dissolved come into contact with each other, whereby the impurities are precipitated or reacted on the limestone surface and are trapped by the limestone. As a result, supercritical water containing almost no impurities is obtained, and the supercritical water can be reused in the reforming reaction of heavy oil, so that it is not necessary to discharge the supercritical water out of the system as wastewater.

The present method can be applied to a case where a very small amount of heavy metal exists in the condensed water.

Most of the trace metal components in the condensed water are present in the form of metal oxides. The metal oxide components pumped together with the condensed water react with limestone as a filler in the trapping step to form C oxide.
Since fixed on limestone as _{aO · V 2 O 5, CaO} · Na 2 O · V 2 O 5, and supercritical water are separated.

As described above, in a system in which heavy oil is lightened with supercritical water and burned while being mixed, impurities such as sulfur oxides and metal oxides absorbed in warm water recovered from combustion exhaust gas are separated. , Can be removed and returned to the supercritical water reactor again for use in lightening heavy oil, and the amount of water used can be reduced. Further, there is no need to discharge wastewater out of the system, and wastewater treatment is not required.

[0017]

(Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a power generation system in which a reformed fuel is produced by supercritical processing of heavy oil, the obtained reformed fuel is burned in a combustor for a gas turbine, and the gas turbine is driven by the combustion gas. The combustion exhaust gas from the gas turbine is recovered by a heat recovery unit, and is purified by environmental devices such as denitration, desulfurization, and dust removal. Then, it is cooled in a cooling step, and the moisture in the combustion exhaust gas is condensed, separated and recovered. After adding alkali and H ₂ O ₂ to the separated and recovered condensed water, pressurize it with a pump, heat it with a reactor and a trap, react at a temperature and pressure above the critical point of water, trap impurities in the condensed water, This is a system for reforming heavy oil with the obtained supercritical water.

In the heavy oil reforming step 1, supercritical water and heavy oil are supplied, and the heavy oil is lightened by the hydrolysis action of the supercritical water. Supercritical water is 25MPa via valve 24,
Feed at 450 ° C to heavy oil reforming process. On the other hand, the heavy oil is supplied to the heat exchanger 29 in the cooling step 14 via the pipe 20 and is indirectly exchanged with the flue gas to heat the heavy oil and to cool the flue gas to reduce the moisture in the flue gas. Condensate to condensed water. The heavy oil heated by the heat exchanger 29 is supplied to the heavy oil reforming step via the supply pipe 21, and is reformed at 380 ° C. and 25 MPa in the heavy oil reforming step. The reformed gas and the supercritical water are heated at 420
The metal component is separated at 25 ° C. at 25 ° C. and burned in the combustor 3. After driving the gas turbine 4, the combustion gas 540
The heat enters the heat recovery unit 5 at about 1 atm. A normal steam generator, a reaction step 12 and a trapping step 13 according to the present invention are inserted into the heat recovery unit 5, and heat is recovered by indirect heat exchange with combustion gas. The combustion exhaust gas that has exited the heat recovery unit 5 is subjected to environmental device 6 to remove SOx, NOx, and dust, and reaches a cooling step 14. The condensed water obtained in the cooling step 14 is stored in a condensed water tank 30 by a drain pipe 28. The amount of S, N, and C of the stored condensed water is measured by the measuring device 8, and the amounts thereof are obtained. The condensed water tank 3 is added to the condensed water tank 3 by the alkali addition device 9 by adding 1.5 times mol of NaOH to the measured mol number of S component.
Supply 0. In addition, three times the number of moles of H ₂ O ₂ obtained by adding the number of moles of S and the number of moles of C are added to the oxidizing agent adding device
To supply to the condensed water tank 30. In addition, the alkali to be added may be KOH other than NaOH, which acts similarly to the treatment of impurities in the condensed water.

The measuring device 8, the alkali addition device 9, the acid
And a condensed water tank 30.
Condensed water from the adjustment step 7
a to the reaction step 12 installed in the heat recovery unit 5.
Sent. In the reaction step 12, the condensed water is heated up to 380 ° C.
When heated, the water becomes supercritical water. In addition, the additive H _Two
O_TwoIs H_TwoO and 1 / 2O_TwoAnd O_TwoIs dissolved in supercritical water
Reacts with the C component_TwoAnd S is SO_Twobecome. Further S
O_TwoReacts with the additive NaOH to_TwoSO_FourBecomes
All of these substances are in the range of 374 ° C to 410 ° C.
It is completely dissolved in supercritical water. Substances that exit the reaction process are captured
Introduced to the catching step 13. Filler supply pipe in the capture step 13
From 27, a filler such as limestone is filled in advance. Also the reaction
Increase the temperature of the fluid flowing from the process to about 430 ° C
You. As a result, Na dissolved in supercritical water_TwoSO_Four, S
O_FourS compounds such as precipitate on the surface of limestone,
Reacts with CaSO_FourNext it is fixed to limestone. The work
Supercritical water from which impurities have been removed in
Return to the heavy oil reforming process 1 via the drain valve 25 and the return pipe 23,
Reuse.

In the present embodiment, the condensed water recovered when the reformed fuel obtained by treating the heavy oil with supercritical water is burned is used for adjusting the condensed water, the pressure pump 11, the reaction step 12, the trapping step 13, and the pressure control valve 25. Impurities were removed from the condensed water using the following configuration. The results are as follows. Case 1 Condensed water: S content 3 mol, C content 4.2 mol NaOH addition amount: 4.5 mol H ₂ O ₂ addition amount: 10.8 mol Reaction step: temperature 380 ° C., pressure 25 MPa Capture step: temperature 430 ° C. , Pressure of 25 MPa, filled with limestone Supercritical water discharged from the pressure control valve 25 S content 0.03 mol, C content 0.002 mol Case 2 condensed water: S content 3 mol, C content 4.2 mol KOH addition amount : 4.5 mol H ₂ O ₂ addition amount: 10.8 mol Reaction step: temperature 380 ° C., pressure 25 MPa Capture step: temperature 430 ° C., pressure 25 MPa, filling with limestone S of supercritical water discharged from the pressure control valve 25 Case 3 Condensed water: S content 3 mol, C content 4.2 mol NaOH addition amount: 3 mol H ₂ O ₂ addition amount: 10.8 mol Reaction step: temperature 380 ℃, pressure 25MPa Capture process: temperature 430 ° C., pressure 25 MPa, filled with limestone 0.05 mol of S component and 0.002 mol of C component of supercritical water discharged from the pressure control valve 25 (Example 2) In this example, exhaust gas finally released to the atmosphere This is configured to prevent white smoke in the inside and to enhance the effect of cooling the combustion exhaust gas from the heat exchanger 5, and will be described with reference to FIG.

The combustion exhaust gas is supplied to a heat recovery unit 5 and an exhaust gas heater 1
After the temperature is reduced by 08, it is supplied to the cooling step 14. In the cooling step 14, an absorption liquid 113 described later is injected from the spray device 104, and the moisture contained in the combustion exhaust gas is cooled to form condensed water 106 containing sulfur oxides and nitrogen oxides. Further, the flue gas is discharged to the mist collector 10
After the mist is removed by 7, the mist is heated by the exhaust gas heater 108 so as not to generate white smoke. A part of the condensed water 106 is pressurized by a pump 105 and the pH is adjusted by a pH adjuster 103.
Supplied to The other condensed water is sent to the adjusting step 7.

The spray device 104 is a device for spraying water as fine droplets. For example, a plurality of spray nozzles are installed on a surface perpendicular to the flow direction of the combustion exhaust gas. Due to the gas-liquid contact in the spray tower, the temperature of the flue gas decreases, and the moisture in the flue gas present as a gas condenses to a liquid. Also, SO ₂ in the combustion exhaust gas is absorbed by the pH-adjusted absorbent. In order to promote absorption and improve desulfurization efficiency from flue gas, a reaction for absorbing SO ₂ in flue gas into a liquid is promoted. In order to accelerate the reaction of absorbing SO ₂ in the gas phase into the liquid, the pH of the absorbing liquid is set to 3.8 or more.

On the other hand, H ₂ O ₂ is added in the adjusting step 7 and the reaction step 12 to completely oxidize the sulfur oxides. To make sulfuric acid. PH of absorption liquid is 2-4
In the above, the production of dithioic acid, which is a sulfur oxide that was not completely oxidized, was maximized, and no dithionic acid was produced at a pH of 6.0 or more. From these facts, the pH of the absorbing solution was adjusted to 6.0 or more. As the pH adjusting agent used in the absorbing solution, slaked stone, quicklime, or caustic soda is used.

The pH of the absorbing solution is adjusted by adjusting the pH of the condensed water 106.
H is checked by the pH meter 101, and the pH controller is controlled to supply the pH adjuster from the pH adjuster supply controller 102 to the pH supplier 103 so that the pH becomes 6.0 or more. The control system for the sulfur and nitrogen compound concentration of the absorbent is p
In the same manner as in the H adjustment, the sulfur and nitrogen compound measuring device 114 checks the concentration.
Supply water is supplied from 15 to the pH adjuster 103, and the pH is controlled so as to be 6.0 or more. The amount of the condensed water 106 is adjusted by detecting the liquid level with a liquid level meter 119, opening and closing a valve 117 with a liquid level controller 118, and controlling the amount of the condensed water to be constant.

In this embodiment, the condensed water is recovered from the flue gas.
Heat exchanger 5, exhaust gas heater 108, cooling process 7,
Playing device 104, mist collector 107, pH adjuster 1
In the condensed water with the configuration consisting of
Material removal was performed. The results are as follows. Case 1 S content in flue gas 109: 70 ppm Flame flue gas 109 temperature: 160 ° C. pH of water in spray device 104: 11.4 Absorbent 113 temperature: 40 ° C. Absorbent 113 pH: 11.3 pH adjuster: NaOH condensed water Concentration of dithionic acid in 106: 0.5 ppm S content in exhaust gas heater 108: 30 ppm Exhaust gas temperature in exhaust gas heater 108: 90 ° C. Case 2 S content in combustion exhaust gas 109: 70 ppm Combustion exhaust gas 109 temperature: 130 ° C. Spray device 104 PH of water in water: 11.4 Absorbent 113 temperature: 40 ° C. Absorbent 113 pH: 11.3 pH adjuster: NaOH Condensed water 106 dithionic acid concentration: 0.7 ppm S content in exhaust gas heater 108: 20 ppm Exhaust gas heating Exhaust gas temperature in vessel 108: 90 ° C. According to the second embodiment, the exhaust gas temperature
Water is collected efficiently and exhausted from the gas turbine.
There is an effect that the generated combustion exhaust gas does not generate white smoke. (Embodiment 3) In this embodiment, an appropriate amount of the adjusting agent in the adjusting step 7 is supplied.
To reduce the corrosion rate of the piping in the reaction step 12
This will be described with reference to FIG. Sulfur oxides
(S _TwoO_Three ^2-, SO_Three ^2-, S_TwoO₆ ^2-), TOC, COD
Measuring instrument 8 to measure, pH adjuster feeder 9, Oxidizer feeder
10 and a condensed water tank 32 _Two
O_TwoReducing the reactor corrosion by adjusting the supply
Can be sustained.

In the adjusting step 7, pH adjustment and oxidation can be performed.
Analyze the substance and add additive and oxidizer to condensed water 30
You. The condensate 30 is stirred to measure the sulfur and carbon concentrations.
The mixture is stirred by the stirrer 31 and collected from the condensed water tank 32. Coagulation
In the contracted water tank 32, the condensed water is stirred by the stirrer 31 to dissolve the water.
Make the liquid concentration uniform. The condensed water stored in the condensed water tank 30
In the sulfur oxide measuring device 132 that measures the sulfur content in the condensed water,
Sulfur oxidation that can be oxidized such as thiosulfuric acid, sulfurous acid, dithionic acid, etc.
The substance concentration is measured by ion chromatography. Each ion
Calculate the change in pH when the species oxidizes to sulfuric acid,
After the completion of the reaction, the pH adjusting agent is adjusted so that the pH becomes 7 to 12.
The supply amount is adjusted by the concentration adjustment controller 131, and the condensed water is adjusted.
It is supplied to the tank 32. In addition, oxidation to each ion species
H required for _TwoO_TwoCalculate the amount of

The measuring device 8 for measuring carbon content measures total organic carbon (TOC). TOC with TOC measuring device 133
Is measured, the amount of hydrogen peroxide supplied is calculated as an amount of H ₂ O ₂ equivalent to ₂ to 3 times the amount of oxygen for oxidizing TOC.

Chemical oxygen demand (COD) is used to determine the supply of oxygen for oxidizing elements other than carbon.
However, in the measurement of COD, the value becomes smaller than the theoretically necessary oxygen amount. A COD measuring device 134 is used for measuring COD. When the COD of sulfurous acid or dithionic acid was measured, it was found that the amount of oxygen required for actual oxidation was 1/8 and 1/4.
Value. Therefore, the equivalent of 2 to 3 times the amount of H ₂ O ₂ calculated by subtracting the amount of oxygen necessary for completely oxidizing the sulfur oxide from the COD value is calculated.

The H ₂ O ₂ amount calculated from the sulfur oxide, TOC, and COD is adjusted by the concentration controller 131 and supplied to the condensed water supply pipe 135 by the oxidizing agent adding device 10.

In this embodiment, the impurities in the condensed water were dithionic acid, organic substances, and metal ions, and were oxidized at 450 ° C. and 25 MPa using H ₂ O _{2 as} an oxidizing agent and NaOH as a pH adjusting agent using a SUS316 pipe. . Table 1 shows the concentration of each component in the stock solution, the concentration of each component in the solution after the treatment, the corrosion rate, and the presence or absence of pitting corrosion.

[0032]

[Table 1]

According to the third embodiment, even when the condensed water containing sulfuric acid is supercritically hydroxylated, impurities in the condensed water can be completely oxidized without causing pitting corrosion. (Embodiment 4) In this embodiment, H added to recover and reuse water after burning a fuel mixture of heavy oil and supercritical water is added.
It is configured to reduce the amount of ₂ O ₂ and will be described with reference to FIG.

When the heavy oil is burned and impurities are collected from the flue gas, the condensed water recovered from the flue gas is removed.
Sulfuric acid, sulfurous acid, nitric acid, nitrous acid, V ₂ O ₅ , metal oxides, and the like are present in 06. These easily generate salts in supercritical water, and are easily separated and removed in the capturing step 13.

FIG. 4 is a schematic diagram showing a conventional configuration. In this method, a tank 321 is pressurized by using a pump 322 and heated by a heat exchanger 323 to bring the tank to a supercritical state. It reacts with an oxygen source in a supercritical reactor 324, cools it in an extractor 325, depressurizes it, takes out a gas component in a gas-liquid separator 327,
Further, the oil is separated into light oil and water by a drain separator 328. NH ₃ , H ₂ S, cyanide, and metals such as sodium, potassium, and vanadium ions dissolve into the separated water. In addition, since oil remains in water, COD and TOC increase.

Table 2 shows the conventional process wastewater and the condensed water properties of the present embodiment.

[0037]

[Table 2]

According to the fourth embodiment, it is possible to completely oxidize impurities in the condensed water by treating the contained components which are easy to treat from the condensed water. (Embodiment 5) This embodiment is designed to recover the moisture in the combustion exhaust gas finally released to the atmosphere to prevent the generation of white smoke. Further, a configuration for increasing the power generation efficiency by increasing the water recovery rate will be described with reference to FIG.

The combustion exhaust gas is supplied to a heat recovery unit 5 and an exhaust gas heater 1
After the temperature is reduced by 08, it is supplied to the cooling step 14. In the cooling step 14, the absorption liquid 1 is supplied from the spray device 104.
13 is injected, the moisture contained in the exhaust gas is cooled,
The condensed water 106 contains sulfur oxides and nitrogen oxides. Further, after removing the mist from the combustion exhaust gas by the mist collector 107, the exhaust gas is heated by the exhaust gas heater 108 to prevent the generation of white smoke.

The effect of the water recovery conditions of the condensed water recovered from the flue gas 109 in the cooling step 14 will be described. Factors affecting the power generation efficiency due to changes in the water recovery conditions include: a) changes in pressure loss (changes in pressure ratio due to the presence or absence of the cooling step 14), b) lower limit temperature of heat recovery (gas temperature in the combustion exhaust gas pipe 110) , C) make-up water temperature and quantity (preheating effect by latent heat recovery at the time of water recovery). Table 3 summarizes the water recovery conditions and their effects.

[0041]

[Table 3]

By setting the water recovery rate to 100% according to this embodiment, the power generation efficiency can be increased by 0.2%. Further, the amount of makeup water can be reduced. Further, in the past, the temperature of the flue gas was raised to prevent the generation of white smoke, but since water is collected and the dew point is lowered, the temperature of the flue gas discharged to the outside of the system can be lowered.

[0043]

According to the present invention, in a system in which heavy oil is lightened with supercritical water and burned while being mixed, sulfur oxides, metal oxides, and the like absorbed in warm water recovered from combustion exhaust gas Can be separated and removed, and returned to the supercritical water reactor again to be used for lightening heavy oil.
Water usage can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an embodiment of a cooling step of the present invention.

FIG. 3 is a diagram showing an embodiment of an adjustment step of the present invention.

FIG. 4 is a schematic diagram showing a conventional configuration.

[Explanation of symbols]

1… heavy oil reforming process, 2… metal separation process, 3… combustor, 4
... gas turbine, 5 ... heat recovery unit, 6 ... environmental device, 7 ... adjustment process, 8 ... measuring device, 9 ... alkali addition device, 10 ... oxidizing agent addition device, 11 ... pressurizing pump, 12 ... reaction process, 13 … Capture process, 14… Cooling process, 15… Heavy oil supply pump, 20… Piping,
21 ... supply pipe, 22 ... discharge pipe, 23 ... return pipe, 24 ... valve, 25
… Pressure control valve, 26… filler discharge pipe, 27… filler supply pipe,
28 ... discharge pipe, 29 ... heat exchanger, 30 ... condensed water tank, 31 ...
Stirrer, 32… Condensed water tank, 101… pH meter, 102… pH
Adjustment agent supply controller, 103: pH adjuster, 104: Spray device, 105: Condensate return pump, 106: Condensate, 107
… Mist collector, 108… Exhaust gas heater, 109… Combustion exhaust gas, 110… Combustion exhaust gas pipe, 111… Combustion exhaust gas, 112… Heavy oil heat exchange pipe, 113… Absorbent, 114… Sulfur content, nitrogen content measurement 115, make-up water supply controller, 116, part of condensed water, 117, valve, 118, liquid level controller, 119, liquid level gauge, 131, concentration adjustment controller, 132, sulfur oxide measuring instrument, 133, TOC Measuring device, 134: COD measuring device, 135: Condensed water supply pipe, 321: Tank, 322: Pump, 323: Heat exchanger, 324: Supercritical reactor, 325: Extractor, 326: Pressure reducing valve, 3
27 ... gas-liquid separator, 328 ... drain separator, 329 ... salt separator, 33
1 ... pump (water supply means), 332 ... compressor (oxygen source supply means), 333 ... screening step, 334 ... pressure flotation step, 335 ... biological treatment step, 336 ... coagulation sedimentation treatment step, 33
7… Sand filtration process.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/72 F23L 17/14 G C10G 31/08 B01D 53/34 125A F23J 15/00 F23J 15/00 B F23L 17/14 (72) Inventor Nobuyuki Hokari 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Power and Electric Development Laboratory, Hitachi, Ltd. No. 1 Hitachi, Ltd. Electricity and Electricity Development Laboratory (72) Inventor Shinichi Inage 7-2, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi, Ltd. Electricity and Electricity Development Laboratory (Reference) 3K070 DA03 DA16 DA49 4D002 AA02 AA12 AB01 AB02 BA02 BA05 BA12 BA16 CA01 DA02 DA05 DA11 DA12 EA12 FA03 FA04 HA07 4D038 AA08 AB31 AB36 AB37 BA02 BA 04 BB13 BB16 4D050 AA12 AB07 AB18 BB09 BC01 BC02 BD06 BD08 CA13 CA20 4H013 AA04

Claims (13)

[Claims] In a system for converting heavy oil to light fuel with supercritical water and generating electricity with the obtained reformed fuel, the supercritical water from which impurities have been removed is converted to supercritical water used in the light fuel conversion step. A system for recovering water from combustion exhaust gas, which is collected and reused as part of water. 2. In a system for converting heavy oil to light fuel with supercritical water and generating electricity with the obtained reformed fuel, a cooling step of cooling combustion exhaust gas and collecting condensed water, and storing the collected condensed water in alkaline water. Or an adjusting step of adding an oxidizing agent, a pressurizing and heating the adjusted condensed water, a reaction step of heating and supercritical water reaction, and a trapping step of separating and removing impurities in the supercritical water from the reaction step. Supercritical water after removing impurities
A water recovery system from combustion exhaust gas, wherein the water is recovered and reused as a part of supercritical water used in the light fuel conversion process. 3. The system for recovering water from combustion exhaust gas according to claim 2, wherein one kind of the coolant used in the cooling step is heavy oil. 4. The method according to claim 2, wherein the alkali added to the adjusting step is one of NaOH and KOH, and the oxidizing agent is H.
A water recovery system from combustion exhaust gas, wherein the system is ₂ O ₂ . 5. The water from the combustion exhaust gas according to claim 4, wherein the amount of the alkali added is determined by measuring the S concentration of the condensed water discharged from the cooling step and setting the concentration to 1 to 2 times the S concentration. Collection system. 6. The method according to claim 4, wherein the oxidizing agent is added in an amount of 2 to 4 times the total mole number of the condensed water discharged from the cooling step by measuring the S concentration and the C concentration. Water recovery system from burning flue gas. 7. The system for recovering water from combustion exhaust gas according to claim 4, wherein the pH of the condensed water discharged from the cooling step is measured and the amount of alkali added is adjusted. 8. The system for recovering water from combustion exhaust gas according to claim 4, wherein the COD in the condensed water is measured, and the added amount of the oxidizing agent is set to 8 to 32 equivalents of the COD value. 9. The method according to claim 2, wherein
A water recovery system from combustion exhaust gas, wherein limestone is filled as a filler in the trapping step. 10. The cooling step according to any one of claims 2 to 9, wherein the cooling step is provided with a spray device for injecting a pH-adjusted absorbing liquid to absorb the SO ₂ in the combustion exhaust gas into the absorbing liquid. A water recovery system from combustion exhaust gas. 11. The method according to claim 2, wherein a step of reacting sulfur oxides with oxygen in air to form sulfuric acid is added to the cooling step. Water recovery system. 12. The system for recovering water from combustion exhaust gas according to claim 2, wherein the adjusting step further comprises a concentration adjusting controller for adjusting the concentration of the supply amount of the pH adjusting agent. . 13. The combustion exhaust gas according to claim 2, wherein a step of removing mist in the combustion exhaust gas cooled in the cooling step and then heating the exhaust gas again is added. Water recovery system.