Sludge dehydrating system and method thereof based on thermal hydrolysis technology

Patent metadata

Field	Value
Publication number	US-9926216-B2
Application number	US-201414917013-A
Country	US
Kind code	B2
Filing date	Nov 10, 2014
Priority date	Apr 3, 2014
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

A sludge dehydrating system and a method thereof based on a thermal hydrolysis technology include: a homogeneous slurry unit, a hydrothermal unit, a flash reactor, a waste heat recovery unit, and a dehydrator; wherein a viscosity of sludge is lowered by homogenously slurrying before entering a pump, which is conducive to transportation; a sludge tank firstly crashes and then quantitatively transports for improving a homogenizing efficiency; a diluent is sludge dehydrated filtrate which is mixed with flash steam in an ejector, wherein an mixing efficiency is high; during homogenously slurrying, waste steam generated is added into a sludge diluent pipe for being absorbed; a hydrothermal unit include a variety of forms such as an intermittent form and a continuous form, in such a manner that reaction parameters, especially reaction time are effectively guaranteed; the flash steam enters the homogeneous slurry unit for heating the sludge.

First claim

What is claimed is:

1. A sludge dehydrating system based on a thermal hydrolysis technology, comprising: a homogeneous slurry unit, a hydrothermal unit ( 3 ), a flash reactor ( 4 ), a waste heat recovery unit, and a dehydrator ( 6 );
wherein the homogeneous slurry unit comprises a sludge tank ( 1 ), a sludge homogenizer ( 2 ) and a first single-screw pump ( 101 ); wherein a bottom portion of the sludge tank ( 1 ) is connected to a sludge inlet at a bottom portion of the sludge homogenizer ( 2 ); a sludge outlet at a top portion of the sludge homogenizer ( 2 ) is connected to an inlet of the hydrothermal unit ( 3 );
wherein an outlet of the hydrothermal unit ( 3 ) is connected to an inlet at a top portion of the flash reactor ( 4 ), and a sludge outlet at a bottom portion of the flash reactor ( 4 ) is connected to an inlet of the waste heat recovery unit;
wherein an outlet of the waste heat recovery unit is connected to the dehydrator ( 6 ); a dehydrating filtrate outlet pipe of the dehydrator ( 6 ) is connected to an inlet of a first low-voltage variable-frequency pump ( 111 ), an outlet of the first low-voltage variable-frequency pump ( 111 ) is connected to an ejecting fluid inlet of an ejector ( 9 ); a steam outlet of the flash reactor ( 4 ) is connected to an ejected fluid inlet of the ejector ( 9 ), an outlet of the ejector ( 9 ) is connected to an ejecting mixture inlet at the bottom portion of the sludge homogenizer ( 2 ), a waste steam outlet at the top portion of the sludge homogenizer ( 2 ) is connected to a sludge diluent outlet of the dehydrator ( 6 ).

2. The sludge dehydrating system, as recited in claim 1 , wherein the sludge outlet of the flash reactor ( 4 ) is connected to an inlet of a second single-screw pump ( 102 ), an outlet of the second single-screw pump ( 102 ) is connected a shell-side inlet of a heat exchanger ( 5 ); a water feeding pipe of a boiler and a cooled water outlet of a cooling tower ( 7 ) are connected to an inlet of a second low-voltage variable-frequency pump ( 112 ), an outlet of the second low-voltage variable-frequency pump ( 112 ) is connected to a pipe-side inlet of the heat exchanger ( 5 ); a pipe-side outlet of the heat exchanger ( 5 ) is divided into two portions and respectively connected to an inlet of a furnace ( 8 ) and an inlet of the cooling tower ( 7 ); a shell-side outlet of the heat exchanger ( 5 ) is connected to the dehydrator ( 6 ).

3. The sludge dehydrating system, as recited in claim 1 , wherein the sludge tank ( 1 ) is placed above the sludge homogenizer ( 2 ); the sludge homogenizer ( 2 ) is placed above the first single-screw pump ( 101 ).

4. The sludge dehydrating system, as recited in claim 1 , wherein the hydrothermal unit ( 3 ) is an intermittent hydrothermal unit ( 13 ) or a continuous hydrothermal unit;
wherein the intermittent hydrothermal unit ( 13 ) comprises a hydrothermal steam heater ( 12 ), a first intermittent hydrothermal reactor ( 131 ) and a second intermittent hydrothermal reactor ( 132 ); wherein an outlet of the first single-screw pump ( 101 ) is connected to a sludge inlet at a bottom portion of the hydrothermal steam heater ( 12 ), a steam outlet of a furnace ( 8 ) is connected to a hydrothermal steam inlet at the bottom portion of the hydrothermal steam heater ( 12 ), an outlet at a top portion of the hydrothermal steam heater ( 12 ) is connected to the first intermittent hydrothermal reactor ( 131 ) and the second intermittent hydrothermal reactor ( 132 ), wherein the first intermittent hydrothermal reactor ( 131 ) and the second intermittent hydrothermal reactor ( 132 ) are connected to each other in parallel; electric stop valves are provided at inlets and outlets of the first intermittent hydrothermal reactor ( 131 ) and the second intermittent hydrothermal reactor ( 132 ); the outlets of the first intermittent hydrothermal reactor ( 131 ) and the second intermittent hydrothermal reactor ( 132 ) are connected to the inlet at the top portion of the flash reactor ( 4 );
wherein the continuous hydrothermal unit comprises a continuous hydrothermal reactor, wherein the continuous hydrothermal reactor is a radial flow hydrothermal reactor ( 14 ) or a tower hydrothermal reactor ( 15 );
wherein the radial flow hydrothermal reactor ( 14 ) is a container with a height-diameter ratio of less than 1, comprising an inner barrel ( 141 ), a guide barrel ( 142 ), an outer barrel ( 143 ), an inner barrel stirrer ( 144 ), and a barrel wall ( 145 ); wherein the inner barrel stirrer ( 144 ) is provided inside the inner barrel ( 141 ), the guide barrel ( 142 ) is provided outside the inner barrel ( 141 ), the outer barrel ( 143 ) is provided at an inner circumference of the barrel wall ( 145 ); the outlet of the first single-screw pump ( 101 ) and the steam outlet of the furnace ( 8 ) are connected to an inlet pipe at a bottom of the inner barrel ( 141 ), an outlet at a bottom portion of a loop space formed between the outer barrel ( 143 ) and the barrel wall ( 145 ) is connected to the inlet at the top portion of the flash reactor ( 4 );
wherein the tower hydrothermal reactor ( 15 ) is a container with an inlet at a bottom portion thereof, an outlet at a top portion thereof, and a height-diameter ration of larger than 2; an axial-force stirrer ( 151 ) is provided at the bottom portion of the tower hydrothermal reactor ( 15 ), a non-axial-force stirrer ( 152 ) is provided at the top portion of the tower hydrothermal reactor ( 15 ); the outlet of the first single-screw pump ( 101 ) and the steam outlet of the furnace ( 8 ) are connected to the inlet at the bottom of the tower hydrothermal reactor ( 15 ), the outlet at the top portion of the tower hydrothermal reactor ( 15 ) is connected to the inlet at the top portion of the flash reactor ( 4 ).

5. A sludge dehydrating method based on a thermal hydrolysis technology, comprising steps of:
1) storing mechanically-dehydrated sludge in a sludge tank ( 1 ), meanwhile crashing the mechanically-dehydrated sludge with a strong shearing force stirrer in the sludge tank ( 1 ), quantitatively inputting crashed granular sludge into a sludge inlet at a bottom portion of a sludge homogenizer ( 2 ) through an auger at a bottom portion of the sludge tank ( 1 ), inputting the sludge treated by the sludge homogenizer ( 2 ) into a first single-screw pump ( 101 ) through a sludge outlet at a top portion of the sludge homogenizer ( 2 ), inputting the sludge treated by the first single-screw pump ( 101 ) into a hydrothermal unit ( 3 ); using a part of dehydrating filtrate from a dehydrator ( 6 ) as a diluent, inputting the diluent into an ejector ( 9 ) through a first low-voltage variable-frequency pump ( 111 ) for ejecting flash steam; after ejecting, inputting a mixed fluid into the sludge homogenizer ( 2 ) for homogenously slurrying, wherein a stirrer is provided inside the sludge homogenizer ( 2 ); inputting waste steam from the sludge homogenizer ( 2 ) into a sludge diluent outlet pipe of the dehydrator ( 6 ) for being absorbed;
2) inputting hydrothermal steam of a waste heat recovery unit into the hydrothermal unit ( 3 ) for heating the sludge, wherein during heating, microbial flocculation in the sludge is dissolved, microbial cells are ruptured, and organics in the sludge is hydrolyzed, so as to lower a viscosity of the sludge and reduce a constraint capacity of emplastics on water;
3) inputting hydrothermal sludge from the hydrothermal unit ( 3 ) into a flash reactor ( 4 ) through a top portion thereof, lowering a pressure by dilatation inside the flash reactor ( 4 ) and throttle at an inlet pipe, flashing the hydrothermal sludge and then absorbing heat for lowering a temperature of the hydrothermal sludge, and finally generating the flash steam and flash sludge, wherein the flash steam enters the ejector ( 9 ) and the flash sl

Assignees

• Univ Xi An Jiaotong
• Xian Wonfu Energy And Environment Tech Co Ltd

Inventors

• Wang Shuzhong
• Qian Lili
• Tang Xingying
• Sun Panpan

Classifications

• Y02W10/40

  Valorisation of by-products of wastewater, sewage or sludge processing · CPC title

• C02F1/06

  Flash evaporation · CPC title

• C02F11/12 Primary

  by de-watering, drying or thickening · CPC title

• C02F11/121

  by mechanical de-watering · CPC title

• C02F2303/10

  Energy recovery · CPC title