KR101652292B1 - Apparatus for Purging Carbon dioxide for Pretreatment for Membrane filtration - Google Patents

Abstract

The present invention relates to a carbon dioxide purging apparatus for filtration membrane scale reduction and, more particularly, to a carbon dioxide purging apparatus for filtration membrane scale reduction to which an inline mixer and a venturi pipe structure are applied so that carbon dioxide and wastewater are mixed with each other with little energy and carbon dioxide supply is controlled depending on pH. The carbon dioxide purging apparatus for filtration membrane scale reduction according to the present invention includes: a body into which wastewater flows to be mixed with carbon dioxide; a carbon dioxide supply unit connected to the body and supplying the carbon dioxide; a pH measuring unit for measuring pH of the wastewater mixed with the carbon dioxide; and a pH linking control unit receiving a pH value from the pH measuring unit. The pH linking control unit blocks carbon dioxide supply when the wastewater mixed with the carbon dioxide has a pH value equal to or less than a pre-set pH value and performs control for carbon dioxide supply when the wastewater mixed with the carbon dioxide has a pH value exceeding the pre-set pH value.

Description

Technical Field [0001] The present invention relates to an apparatus for purifying carbon dioxide,

The present invention relates to a carbon dioxide purging apparatus for reducing the scale of a filtration membrane. More particularly, the present invention relates to a carbon dioxide purging apparatus for reducing carbon dioxide To a carbon dioxide purging apparatus for reducing scale.

Methods for treating and purifying contaminated water include various methods such as precipitation, ultraviolet rays, microorganisms, chlorine treatment, and membrane filtration. In recent years, many attempts have been made to realize water purification or water treatment quality improvement and compactness of facilities have.

This is due to the lack of sufficient water resources and the need for environmental conservation, and the waste water discharge facilities above a certain scale require the treatment water to be reused.

Among them, there is a great deal of interest in the market for highly treated wastewater by membrane filtration, which facilitates upgrading of wastewater treatment and facility compactness.

Membrane filtration refers to an operation for separating particulate pollutants in raw water and polluted water through a membrane as a selective partition wall. The membrane that can be used can be selected according to the object to be removed, pore size, operating pressure, and the like.

Typical membrane types include reverse osmosis membrane, nanofilter membrane, ultrafilter membrane, and microfilter membrane.

However, in the membrane filtration method, various kinds of fouling phenomena occur on the surface of the membrane as the filtration proceeds, and generation of scale (calcium carbonate, calcium sulfate, etc.) is regarded as the most serious problem.

 When the scale is generated, the pumping power of the membrane module operated by the pressurization type suddenly rises, causing various fatal problems such as economical deterioration and mechanical stability deterioration. To prevent such problems, an acid solution and a scale inhibitor Lower the pH of the influent to induce the scaling agents to remain in solution in ionic form.

Korean Patent Laid-Open No. 10-2015-0113455 (a reverse osmosis membrane scale inhibitor including phosphorus and a production method thereof) is prepared by mixing 2-acrylamido-2-methylpropanesulfonic acid in addition to acrylic acid as a monomer of a polymer for preventing scale, By using sodium hypophosphite as a chain transfer agent, calcium scales as well as other scale inhibiting effects are excellent, and as a result, more reverse osmosis water can be produced per unit time, and operation costs such as cleaning cost and membrane replacement cost And a method for producing the scale inhibitor.

However, the scale inhibitor accounts for 30 to 40% or more of the total amount of the chemical used in the membrane process, which is not economical. Especially, in the case of the scale inhibitor containing the ammonia compound, the byproduct generated after the reaction may generate a green tide or red tide .

On the other hand, carbon dioxide is an industrial by-product that can be commonly generated in industries such as thermal power plants, steel mills, and cement factories. Most carbon dioxide is discharged into the atmosphere as greenhouse gases without proper treatment, Many attempts have been made to recycle carbon dioxide as part of Carbon Capture & Storage (CCS) technology.

Carbon dioxide is dissolved in the form of carbonic acid in water to reduce the pH and can be used as a substitute for the scale formation inhibitor of the membrane.

Korean Patent No. 10-0970427 (a high-speed coagulated wastewater treatment apparatus using fine bubbles) comprises a chemical injection line through which a coagulant is injected into a wastewater transfer line for introducing wastewater into a storage tank, a gas inlet line through which air or carbon dioxide is injected And a pump for pressurizing the wastewater containing the coagulant and the bubbles is connected. At the downstream end of the pump, a high-speed coagulation apparatus for mixing the coagulant, fine bubbles, and wastewater is connected while the bubbles are crushed to produce fine bubbles A waste water treatment device.

However, in the wastewater treatment apparatus of the patent document, a coagulant is used, and a coagulation agent and a high-speed coagulation apparatus for mixing carbon dioxide with wastewater are rotated by a rotational force from a drive motor, and a pump for pressurizing wastewater There is a limit in that a large amount of power for driving the apparatus can not be generated.

 As such, carbon dioxide is an eco-friendly material that does not generate harmful by-products. It can be used for scale reduction in membrane filtration water treatment design and process for seawater desalination and sewage reuse, but it can be driven at low power, There is no technology related to an efficient carbon dioxide purging apparatus capable of increasing the amount of the carbon dioxide purging apparatus.

Korean Patent Publication No. 10-2015-0113455 (Anti-scale agent for reverse osmosis membrane containing phosphorus and method for producing the same) Korean Patent No. 10-0970427 (High Accumulation Type Wastewater Treatment Apparatus Using Micro Bubbles)

In order to solve the above problems, an object of the present invention is to provide a carbon dioxide purging apparatus for reducing a scale of a filtration membrane that mixes carbon dioxide with wastewater with low energy by applying an inline mixer and a venturi pipe structure.

Another object of the present invention is to provide a carbon dioxide purging apparatus for reducing the scale of a filtration membrane, characterized in that the supply of carbon dioxide is controlled according to pH.

In order to achieve the above object, the present invention provides a carbon dioxide purging apparatus for reducing a scale of a filtration membrane, comprising: a body into which waste water is introduced and the waste water is mixed with carbon dioxide; A carbon dioxide supply unit connected to the body for supplying carbon dioxide; A pH meter for measuring pH of wastewater mixed with carbon dioxide; And a pH interlocking controller for interrupting the supply of carbon dioxide when the wastewater containing carbon dioxide is below a predetermined pH value by receiving the pH value of the pH meter and controlling the supply of carbon dioxide when the wastewater is above a predetermined pH value .

Wherein the body includes a wastewater inlet pipe into which wastewater flows and whose diameter gradually decreases along a direction in which the wastewater flows; A connection pipe connected to the outlet side of the wastewater inflow pipe and formed in the shape of a tube having the same inner diameter, and a carbon dioxide supply unit connected to the one side of the pipe; An enlargement pipe connected to the outlet of the connection pipe and having a diameter gradually increased, and a mixer connected to the enlargement pipe and including a mixer for mixing carbon dioxide and wastewater.

Wherein the mixer is an inline mixer having a streamlined twisted element.

And the carbon dioxide supply unit is connected between the center point of the connection pipe and the end point of the connection pipe.

Wherein the ratio of the maximum diameter of the wastewater inlet pipe, the connecting pipe, and the enlarging pipe is 2: 3: 1: 3 to 4.

Wherein a horizontal length ratio of the wastewater inlet pipe, the connection pipe and the enlarging pipe is 2: 3: 1: 3 to 4.

The carbon dioxide supply unit includes a carbon dioxide storage tank for storing carbon dioxide; A pressure regulator for regulating the pressure in the carbon dioxide storage tank; And a carbon dioxide injection pipe connected to the body for injecting carbon dioxide stored in the carbon dioxide storage tank.

And the carbon dioxide injection pipe includes a membrane diffuser for diffusing carbon dioxide to increase the contact surface area with the wastewater.

As described above, the carbon dioxide purging apparatus for reducing the scale of the filtration membrane according to the present invention has an effect of mixing carbon dioxide with wastewater with low energy by applying an inline mixer and a venturi pipe structure.

In addition, according to the carbon dioxide purging apparatus for reducing the scale of the filtration membrane according to the present invention, the supply of carbon dioxide is controlled according to the pH to maintain the pH constant.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the entire configuration of a carbon dioxide purging apparatus for reducing the scale of a filtration membrane according to the present invention. FIG.
2 is a block diagram showing a configuration of a body 10 according to the present invention.

Specific features and advantages of the present invention will be described in detail below with reference to the accompanying drawings. The detailed description of the functions and configurations of the present invention will be omitted if it is determined that the gist of the present invention may be unnecessarily blurred.

The present invention relates to a carbon dioxide purging apparatus for reducing the scale of a filtration membrane. More particularly, the present invention relates to a carbon dioxide purging apparatus for reducing carbon dioxide To a carbon dioxide purging apparatus for reducing scale.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing the entire configuration of a carbon dioxide purging apparatus for reducing a scale of a filtration membrane according to the present invention. FIG.

A carbon dioxide purging apparatus for reducing the scale of a filtration membrane of the present invention comprises a body (10) into which wastewater flows, a wastewater mixed with carbon dioxide and a body, a carbon dioxide supplying unit (20) for supplying carbon dioxide, A pH meter 30 for measuring the pH of the mixed wastewater, and a controller 40 for stopping the supply of carbon dioxide when the pH of the wastewater mixed with the carbon dioxide is below the predetermined pH value, And a pH interlocking controller (40) for controlling the pH interlocking controller (40).

2 is a block diagram showing a configuration of a body 10 according to the present invention.

The body 10 of the present invention includes a wastewater inlet pipe 11 into which wastewater flows and whose diameter gradually decreases along the direction in which the wastewater flows and a pipe connected to the outlet side of the wastewater inlet pipe, An enlarged pipe (13-a) connected to the outlet of the connecting pipe and having a diameter gradually increased, and a connecting pipe (12) connecting the carbon dioxide supplying unit And a mixer (13-b) for mixing the mixed gas (13).

The maximum diameters of the wastewater inflow pipe 11, the connection pipe 12 and the enlarging pipe 13-a are A1, A2 and A3, respectively, and the wastewater inflow pipe 11, the connection pipe 12, The length of the wastewater inflow pipe 11, the connecting pipe 12, and the enlarging pipe 13-a is set such that when the length ratio of the pipe 13-a in the horizontal direction (parallel to the traveling direction of the fluid) The ratio of the maximum diameter and the length in the horizontal direction is preferably 2 to 3: 1: 3 to 4.

Preferably, the ratio of the maximum diameter of the wastewater inlet pipe and the connection pipe to the length of the connection pipe in the horizontal direction is 2 to 3: 1. If the ratio is less than 2: 1, the rate of increase of the flow velocity is small and the carbon dioxide is smoothly introduced The pressure of the fluid flowing through the connecting pipe is continuously increased, and the flow rate of the fluid flowing through the connecting pipe is continuously increased. A phenomenon of lowering appears. The pressure reduction phenomenon is recovered again after passing through the expansion pipe. However, since the pipe friction loss can not be restored to the supply pressure and the pressure to be mixed with the mixer is lowered, the mixture of carbon dioxide and wastewater can be deteriorated.

The ratio of the maximum diameter to the maximum diameter and the length in the horizontal direction of the enlarged pipe 13-a and the connecting pipe 12 is preferably 3 to 4: 1. If the ratio is smaller than 3: 1, And if it is larger than 4: 1, the initial pressure of the fluid passing through the expansion pipe can be increased but the flow rate is continuously lowered. As a result, the pressure to be introduced into the mixer is lowered, .

The mixer 13-b preferably uses an in-line mixer having a streamlined twisted element.

The inline mixer is composed of rectangular and elliptical plates, each of which has a 180 ° twist in the left and right directions. Each fluid passes through the element. When the fluid passes through the element, And is a device which is divided and mixed and stirred.

The mixing principle of the inline mixer effectively mixes the fluid by Division of flow, Change of flow, and Reversion of flow.

More specifically, the fluid in the inline mixer is divided into two parts when passing through one element. In the case of passing through a plurality of elements, the number of divisions expands (expands) exponentially, and along the twist plane in the element, (Reversing) the turbulent stirring (inversion) by receiving a sudden change of the inertial force by changing the direction of rotation every time one element is passed, The castle is very good.

The mixability of the inline mixer is not a mechanical rotation using an impeller or the like but is caused by the shape and rotation of the element fixed in the mixer pipe and it is not necessary to provide a separate external power device for agitating tank and agitation, , It can be said that it is very efficient in terms of economy because of easy maintenance.

1, the carbon dioxide supply unit 20 is connected to the connection pipe 12 to supply carbon dioxide. The carbon dioxide supply unit 20 includes a carbon dioxide storage tank 21 for storing carbon dioxide, A pressure regulating part 22 for regulating the pressure in the storage tank, and a carbon dioxide injection pipe 23 connected to the body for injecting carbon dioxide stored in the carbon dioxide storage tank.

At this time, the carbon dioxide storage tank 21 must be maintained at a predetermined pressure for introducing carbon dioxide in the carbon dioxide storage tank into the body according to an on / off signal of the pH interlocking controller 40 to be described later, (22) is provided to regulate the pressure in the carbon dioxide storage tank.

That is, the injection of the carbon dioxide is performed not according to the pump which consumes electric power but according to the on / off signal sent from the pH interlocking controller 40.

More specifically, the carbon dioxide storage tank 21 and the carbon dioxide injection pipe 23 are provided with an injection opening / closing means 25. When the pH interlock control unit 40 sends an 'on' signal, the opening / The carbon dioxide in the carbon dioxide storage tank is introduced into the body by the internal pressure.

The carbon dioxide injection pipe 23 is connected to a predetermined position of the connection pipe 12 to introduce carbon dioxide stored in the carbon dioxide storage tank 21 into the waste water.

At this time, the carbon dioxide supply unit 20 is connected between the center point of the connection pipe 12 and the end point of the connection pipe.

The pressure gradually increases from the connecting pipe 12 having a narrow diameter to the enlarging pipe 13-a having a wide pipe diameter, and at the same time, the carbon dioxide can be mixed at a wider angle.

That is, between the center point of the connection pipe 12 and the end point of the connection pipe, the pressure of the fluid passing through the point becomes close to the expansion pipe 13-a so that carbon dioxide can be smoothly introduced into the wastewater Therefore, the mixing ability of carbon dioxide is improved.

However, when the carbon dioxide supplying unit 20 is connected to the enlarging pipe, it is preferable that the pressure of the fluid passing through the enlarging pipe does not deviate from the point range because it becomes large enough to interfere with the inflow and mixing of carbon dioxide.

In addition, the carbon dioxide injection pipe 23 includes a membrane diffuser 24 therein to atomize carbon dioxide before being supplied to the body, thereby increasing the contact surface area with the wastewater, thereby enabling dispersion and diffusion to be more easily performed.

The membrane diffuser 24 is not limited as long as it is capable of atomizing and nitrifying carbon dioxide, but specific examples thereof include a nano-sized membrane single membrane, a nano-sized membrane membrane laminated layer, and porous ceramics.

The position of the membrane diffuser 24 is not limited, but it is preferable that the position of the end of the carbon dioxide injection tube 23 ending at the end of the carbon dioxide injection tube 23 is changed, before the introduction of the nano- As shown in FIG.

A pH meter 30 is provided at a predetermined position between the connection pipe 12 and the mixer 13-b to measure the pH of the wastewater mixed with carbon dioxide. In the pH interlock control unit 40, The supply of carbon dioxide is stopped when the wastewater containing carbon dioxide is below a preset pH value, and the supply of carbon dioxide is controlled when the pH value is exceeded.

More specifically, when the predetermined pH for reducing the scale of the filtration membrane is 6, if the pH of the wastewater mixed with carbon dioxide has a value of 6 or less, the supply of carbon dioxide is interrupted in the pH interlocking controller 40, If it exceeds 6, carbon dioxide will be supplied. If the pH is restored by the supplied carbon dioxide, the supply of carbon dioxide will be blocked again.

At this time, the pH interlocking control can be performed by PI control, MFC control, and the like.

As described above, the carbon dioxide purging apparatus according to the present invention is used for reducing the fouling phenomenon of the membrane by lowering the pH of the wastewater before passing the wastewater through the filtration membrane. By applying the inline mixer and the venturi tube structure, It is possible to maintain the pH constant by mixing with wastewater and controlling the supply of carbon dioxide according to the pH.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken as limiting the scope of the present invention. The present invention can be variously modified or modified. The scope of the invention should, therefore, be construed in light of the claims set forth to cover many of such variations.

10: Body
11: Wastewater inlet pipe
12: Connector
13:
13-a: Expansion tube
13-b: Mixer
20:
21: Carbon dioxide storage tank
22: Pressure regulator
23: Carbon dioxide injection tube
24: Membrane diffuser
25: opening / closing means
30: pH meter
40: pH interlocking controller

Claims (8)

A carbon dioxide purging apparatus for reducing the scale of a filtration membrane,
A body into which wastewater is introduced and the wastewater is mixed with carbon dioxide;
A carbon dioxide supply unit connected to the body for supplying carbon dioxide;
A pH meter for measuring pH of wastewater mixed with carbon dioxide;
And a pH interlocking controller for interrupting the supply of carbon dioxide when the wastewater containing carbon dioxide is below a predetermined pH value by receiving the pH value of the pH meter and controlling the supply of carbon dioxide if the wastewater is above a predetermined pH value ,
The carbon dioxide supply unit
A carbon dioxide storage tank for storing carbon dioxide;
A pressure regulator for regulating the pressure in the carbon dioxide storage tank;
And a carbon dioxide injection pipe connected to the body for injecting carbon dioxide stored in the carbon dioxide storage tank,
The carbon dioxide injection pipe
And a membrane diffuser for diffusing carbon dioxide to increase the contact surface area with the wastewater
A carbon dioxide purging device for reducing filtration membrane scale.
The method according to claim 1,
The body
A wastewater inflow tube into which wastewater flows and whose diameter gradually decreases along a direction in which wastewater flows;
A connection pipe connected to the outlet side of the wastewater inflow pipe and formed in the shape of a tube having the same inner diameter, and a carbon dioxide supply unit connected to the one side of the pipe;
And a mixer connected to the outlet of the connection pipe and having a diameter gradually increased and a mixer connected to the expansion pipe to mix the carbon dioxide and the waste water,
A carbon dioxide purging device for reducing filtration membrane scale.
3. The method of claim 2,
The mixer
Characterized in that it is an inline mixer having a streamlined twisted element
A carbon dioxide purging device for reducing filtration membrane scale.
3. The method of claim 2,
Characterized in that a carbon dioxide supply is connected between a central point of the connection pipe and a point at which the connection pipe ends
A carbon dioxide purging device for reducing filtration membrane scale.
3. The method of claim 2,
Wherein the ratio of the maximum diameter of the wastewater inlet pipe, the connecting pipe, and the enlarging pipe is 2: 3: 1: 3 to 4
A carbon dioxide purging device for reducing filtration membrane scale.
3. The method of claim 2,
Wherein a horizontal length ratio of the wastewater inlet pipe, the connection pipe and the enlarging pipe is 2: 3: 1: 3 to 4
A carbon dioxide purging device for reducing filtration membrane scale.
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