Near-zero-release treatment system and method for high concentrated organic wasterwater

Abstract

A near-zero-release treatment system and method for high concentrated organic wastewater is in the chemical engineering and environment protection field, whose core technology is SCWO. The wastewater and sludge are grinded by the homogeneous pump, pressurized by high-pressure plunger pump, transported to successive pipeline for preheating and mixing with the oxygen and undergoes SCWO reaction in the reactor. After pressure release in the pressure relief device, the reacted fluid passes through the self-cleaning filter and gas liquid separator for insoluble solid and gas separation; then enters the MVR for crystallization of the soluble salts to realize near-zero-release of the feeding. The regular water treatment technology (coagulation sedimentation, membrane biotechnology, membrane technology, etc.) is adopted to complement SCWO, which lowers the operating parameters of the reactor and cuts the operating cost by treating the remaining COD with regular water treatment technology.

Claims

1. A near-zero-release process system for high concentrated organic wastewater, comprising: a wastewater transport unit, a reaction unit, an oxygen supplying unit and a reprocessing unit, wherein the wastewater transport unit comprises a sludge tank (1) and a sludge buffer tank (3), wherein a homogeneous emulsification pump (2) is on a pipe between the sludge tank (1) and the sludge buffer tank (3); the reaction unit comprises a heat exchanger (5) and a tubular reactor (6); a high-pressure variable-frequency plunger pump (4) is on a pipe between the sludge buffer tank (3) and the heat exchanger (5); an outlet of a pipe side of the heat exchanger (5) is connected to an inlet of the tubular reactor (6); an outlet of the tubular reactor (6) is connected to an inlet of a shell side of the heat exchanger (5); the oxygen supplying unit is connected to the tubular reactor (6); the reprocessing unit comprises a pressure relief device (7), a self-cleaning filter (8), a gas liquid separator (9), a MVR (mechanical vapor recompression) crystallization unit (10) and an advanced treatment unit (11); wherein an outlet of the shell side of the heat exchanger (5) is connected to an inlet of the pressure relief device (7); an outlet of the pressure relief device (7) is connected to an inlet of the self-cleaning filter (8); an outlet of a clean fluid of the self-cleaning filter (8) is connected to the gas liquid separator (9); an air vent is set on a top of the gas liquid separator (9); a liquid outlet is set on a bottom of the gas liquid separator (9); the liquid outlet on the bottom of the gas liquid separator (9) is connected to an inlet of the MVR crystallization unit (10); an outlet of the MVR crystallization unit (10) is connected to an inlet of the advanced treatment unit.

2. The near-zero-release process system for the high concentrated organic wastewater, as recited in claim 1, wherein the oxygen supplying unit comprises a liquid oxygen tank (12), a low temperature liquid oxygen pump (13), a liquid oxygen carburetor (14), a oxygen buffer tank (15) and an oxygen adding mixer (16); wherein an outlet of the liquid oxygen tank (12) is connected to an inlet of the low temperature liquid oxygen pump (13); an outlet of the low temperature liquid oxygen pump (13) is connected to a shell side inlet of the liquid oxygen carburetor (14); a shell side outlet of the liquid oxygen carburetor (14) is connected to an inlet of the oxygen buffer tank (15); an outlet of the oxygen buffer tank (15) is connected to an inlet of the oxygen adding mixer (16); the oxygen adding mixer (16) is connected to a gas inlet of the tubular reactor (6).

3. The near-zero-release process system for the high concentrated organic wastewater, as recited in claim 1, wherein the advanced treatment unit (11) adopts an activated carbon absorption device, an ultrafiltration device or a membrane concentration device.

4. The near-zero-release process system for the high concentrated organic wastewater, as recited in claim 1, wherein the self-cleaning filter (8) adopts a rotary scraper type self-cleaning filter.

5. The near-zero-release process system for the high concentrated organic wastewater, as recited in claim 1, wherein solutes at an entrance of the MVR crystallization unit (10) are sodium chloride, sodium sulfate or sodium carbonate.

6. A method for near-zero-release treating of a high concentrated organic wastewater based on a system recited in claim 2 comprising steps of: 1) grinding organic wastewater and sludge stored inside the sludge tank (1) by the homogeneous emulsification pump (2) until a grain size is smaller than a set value; testing the grain size of a grinded water-contained sludge in a sludge buffer tank (3); 2) pumping water-contained sludge which is treated in the step (1) into a heat exchanger by a high-pressure variable-frequency plunger pump (4); the water-contained sludge exchanging heat with a medium at 500° C. and then entering a tubular reactor (6); 3) carrying out homogeneously reaction between oxygen provided by the oxygen supplying unit and organic substances in wastewater treated in the step 2) under supercritical conditions; decomposing the organic substance into CO.sub.2, N.sub.2 and H.sub.2O; leading a reacted high temperature fluid to a heat exchanger (5); exchanging heat between the fluid and an aqueous medium; cooling down the fluid to 80° C.; 4) reducing pressure of the high temperature fluid treated in the step 3) in a pressure relief device (7); discharging insoluble solids through the self-cleaning filter (8); separating a gas and a liquid through the gas liquid separator (9); discharging the separated gas to atmosphere; leading the separated liquid to a MVR crystallization unit (10); and 5) removing soluble salts from the high temperature fluid through the MVR crystallization unit (10); treating the remained COD (chemical oxygen demand) and NH.sub.3—N in the advanced treatment unit (11); realizing a near-zero-release of the industrial wastewater and sludge, which meets the requirements of the national standard.

7. The method for near-zero-release treating of the high concentrated organic wastewater, as recited in claim 6, wherein in the step 3), the oxygen provided by the oxygen supplying unit is liquid oxygen from the liquid oxygen tank (12), which passes through the low temperature liquid oxygen pump (13), enters the liquid oxygen carburetor (14) to be transformed into gas, enters the oxygen buffer tank (15) and finally enters the tubular reactor (6).

8. The method for near-zero-release treating of the high concentrated organic wastewater, as recited in claim 6, wherein in the step 3), the supercritical conditions are that a temperature is 560° C. and a pressure is 26 MPa.

9. The method for near-zero-release treating of the high concentrated organic wastewater, as recited in claim 6, wherein in the step 4), exit conditions of the pressure relief device (7) are that a temperature is 80° C. and a pressure is 0.4 MPa, a temperature and a pressure of the self-cleaning filter (8) are set to 80° C. and 0.4 MPa respectively.

10. The method for near-zero-release treating of the high concentrated organic wastewater, as recited in claim 6, wherein treating a capability of the MVR crystallization unit is 2.13 t/h and evaporation is 2 t/h.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 is a perspective view of a near-zero-release treatment system for a high concentrated organic wastewater and sludge.

[0037] Element number: 1—sludge tank; 2—homogeneous emulsification pump; 3—sludge buffer tank; 4—high—pressure variable—frequency plunger pump; 5—heat exchanger; 6—tubular reactor; 7—pressure relief device; 8—self-cleaning filter; 9—gas liquid separator; 10—MVR crystallization unit; 11—advanced treatment unit; 12—liquid oxygen tank; 13—low temperature liquid oxygen pump; 14—liquid oxygen carburetor; 15—oxygen buffer tank; 16—oxygen adding mixer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0038] Referring to FIG. 1 of the drawings, according to a preferred embodiment of the present invention is illustrated. The embodiment is an explanation not a limitation of the present invention, wherein

[0039] a near-zero-release process system for high concentrated organic wastewater, comprising: a wastewater transport unit, a reaction unit, an oxygen supplying unit and a reprocessing unit, wherein

[0040] the wastewater transport unit comprises a sludge tank 1, a sludge buffer tank 3, a homogeneous emulsification pump 2 is on a pipe between the sludge tank 1 and the sludge buffer tank 3; the reaction unit comprises a heat exchanger 5 and a tubular reactor 6; a high-pressure variable-frequency plunger pump 4 is on a pipe between the sludge buffer tank 3 and the heat exchanger 5; a outlet of a pipe side of the heat exchanger 5 is connected to an inlet of the tubular reactor 6; an outlet of the tubular reactor 6 is connected to an inlet of a shell side of the heat exchanger 5; the oxygen supplying unit is connected to the tubular reactor 6;

[0041] the reprocessing unit comprises a pressure relief device 7, a self-cleaning filter 8, a gas liquid separator 9 and a MVR (mechanical vapor recompression) crystallization unit 10; an outlet of the shell side of the heat exchanger 5 is connected to an inlet of the pressure relief device 7; an outlet of the pressure relief device 7 is connected to an inlet of the self-cleaning filter 8; an outlet of a clean fluid of the self-cleaning filter 8 is connected to the gas liquid separator 9; an air vent is set on a top of the gas liquid separator 9; a liquid outlet is set on a bottom of the gas liquid separator 9; the liquid outlet on the bottom of the gas liquid separator 9 is connected to an inlet of the MVR crystallization unit 10; the reprocessing unit further comprises a advanced treatment unit 11; an outlet of the MVR crystallization unit 10 is connected to an inlet of the advanced treatment unit 11;

[0042] the oxygen supplying unit comprises a liquid oxygen tank 12, a low temperature liquid oxygen pump 13, a liquid oxygen carburetor 14, a oxygen buffer tank 15 and an oxygen adding mixer 16; an outlet of the liquid oxygen tank 12 is connected to an inlet of the low temperature liquid oxygen pump 13; an outlet of the low temperature liquid oxygen pump is connected to a shell side inlet of the liquid oxygen carburetor 14; a shell side outlet of the liquid oxygen carburetor 14 is connected to an inlet of the oxygen buffer tank 15; an outlet of the oxygen buffer tank 15 is connected to an inlet of the oxygen adding mixer 16; the oxygen adding mixer 16 is connected to a gas inlet of the tubular reactor 6;

[0043] solutes at an entrance of the MVR crystallization unit 10 are sodium chloride, sodium sulfate or sodium carbonate;

[0044] the self-cleaning filter 8 adopts a rotary scraper type self-cleaning filter; the filter fineness is extremely high; the filter is capable of continuously-running under pressure and filtering out the insoluble solids in the water;

[0045] the advanced treatment unit 11 adopts regular water treatment technology such as activated carbon absorption, ultrafiltration or membrane concentration technology; the remaining COD (chemical oxygen demand) after supercritical water oxygen reaction is removed by the advanced treatment unit which lowers the required temperature and pressure parameters of the supercritical water oxygen reaction and cuts the cost by compromising the material quality and reducing the operating temperature.

[0046] The present invention publics a method for near-zero-release treating of the high concentrated organic wastewater based on the system, comprising the following steps: [0047] 1) grinding the organic wastewater and sludge stored inside the sludge tank by the homogeneous emulsification pump until a grain size is smaller than a set value; testing the grain size of a grinded water-contained sludge in the sludge buffer tank; [0048] 2) pumping the water-contained sludge which is treated in the step (1) into the heat exchanger by the high-pressure variable-frequency plunger pump; the water-contained sludge exchanging heat with a medium at 500° C. and then entering the tubular reactor; [0049] 3) oxygen provided by the oxygen supplying unit homogeneously reacting with an organic substance in wastewater treated in the step 2) under supercritical conditions; the organic substance is decomposed into CO.sub.2, N.sub.2 and H.sub.2O; a reacted high temperature fluid entering the heat exchanger; the fluid exchanging heat with an aqueous medium and being cooled down to 80° C.; [0050] 4) reducing a pressure of the high temperature fluid treated in the step 3) in the pressure relief device; discharging insoluble solids through the self-cleaning filter; separating a gas and a liquid through the gas liquid separator; discharging the separated gas to atmosphere; the separated liquid entering the MVR crystallization unit; and [0051] 5) removing soluble salts from the high temperature fluid through the MVR crystallization unit; entering the advanced treatment unit; realizing a near-zero-release of the industrial wastewater and sludge.

[0052] The working principle of the above system and method is as below: [0053] (1) the organic wastewater and sludge is stored in the sludge tank 1 and is grinded to a set grain size by the homogeneous emulsification pump 2; the insoluble solid sludge particles smaller than the set value flows at a set flow velocity without deposition in the pipelines of the system, which ensures a smooth flow at a regular flow velocity; the grinded water-contained sludge enters the sludge buffer tank 3 for further grain size test; then the water-contained sludge passes through the high-pressure variable-frequency plunger pump 4 and enters the heat exchanger 5; the cold sludge exchanges heat with a medium whose inlet temperature is 500° C.; then the sludge enters the tubular reactor 6; the liquid oxygen from the liquid oxygen tank 12 passes through the low temperature liquid oxygen pump 13, enters the liquid oxygen carburetor 14 to be transformed into gas, enters the oxygen buffer tank 15 and finally enters the tubular reactor 6 to mix and react with the organic wastewater; [0054] (2) the oxygen and the organic substances in the wastewater homogeneously react in the tubular reactor 6 under the supercritical conditions (560° C., 26 MPa); the organic substances is oxidized and decomposed rapidly and thoroughly into CO.sub.2, N.sub.2 and H.sub.2O; the reacted high temperature fluid enters the heat exchanger and is cooled down to 80° C.; the cooling method is heat exchange with the medium water; then the fluid enters the pressure relief device