KR102494796B1 - Method for manufacturing biofuel - Google Patents

Abstract

An invention related to a biofuel manufacturing method is disclosed. In one embodiment, the biofuel production method includes a gas inlet line into which exhaust gas containing carbon monoxide is introduced, a pH probe provided above the gas inlet line, and a first input line provided above the pH probe and into which a pH adjuster is introduced. Including, a reactor equipped with a reaction medium containing anaerobic microorganisms therein; And a rotation means provided at one side of the lower part of the reactor; a biofuel production method using a biofuel production apparatus, comprising culturing anaerobic microorganisms in the reaction medium using exhaust gas and a pH adjuster introduced into the reactor, and fermenting to prepare a mixed fermentation broth; and purifying ethanol from the mixed fermentation broth, and the exhaust gas containing carbon monoxide includes converter gas (LDG).

Description

Bio fuel manufacturing method {METHOD FOR MANUFACTURING BIOFUEL}

The present invention relates to a biofuel production method. More specifically, it relates to a biofuel manufacturing method with excellent productivity and economy through real-time gas composition analysis during biofuel production using a biofuel manufacturing apparatus.

In the integrated steelmaking process, a large amount of by-product gases such as coke oven gas (COG), blast furnace gas (BFG), and converter gas (LDG) are generated. Conventionally, such by-product gas was reused in a steel making process such as a hot air furnace, a heating furnace, or a boiler, or sent to a power plant and used to generate electricity. The blast furnace gas and converter gas contain carbon monoxide (CO), and their compositions reach about 25% by volume and 55% by volume, respectively. When the carbon monoxide is discharged to the outside, a pollution problem occurs. In addition, even when the carbon monoxide is used as a fuel source and discharged in a burnt state, there is a limit to being a low-quality energy source.

Accordingly, various technologies such as methane gasification and bioethanol production are being developed rather than reusing the carbon monoxide in the process.

The bioethanol production process is produced using coke oven gas (LDG) containing a large amount of CO among by-product gases generated in steel mills. LDG is introduced into an ethanol production reactor through gas treatment and pressure boosting, where ethanol is produced through a microbial reaction, and the produced ethanol is manufactured and sold as high purity ethanol through purification facilities. In addition, additional effects such as steam production using residual gas generated during the bioethanol production process can be generated. The steam generated here can be recycled as energy required during the process to improve the efficiency of the process.

Background art related to the present invention is disclosed in Republic of Korea Patent Publication No. 2019-0099416 (published on August 27, 2019, title of the invention: method and apparatus for producing biofuel).

According to one embodiment of the present invention, it relates to a method for producing biofuel that minimizes variation in the flow rate and composition of carbon monoxide-containing gas.

According to one embodiment of the present invention, it relates to a biofuel production method that minimizes the inflow of oxygen (O ₂ ).

According to one embodiment of the present invention, it relates to a biofuel manufacturing method with excellent productivity and economy.

One aspect of the present invention relates to a method for producing biofuels. In one embodiment, the biofuel production method includes a gas inlet line into which exhaust gas containing carbon monoxide is introduced, a pH probe provided above the gas inlet line, and a first input line provided above the pH probe and into which a pH adjuster is introduced. Including, a reactor equipped with a reaction medium containing anaerobic microorganisms therein; And a rotation means provided at one side of the lower part of the reactor; a biofuel production method using a biofuel production apparatus, comprising culturing anaerobic microorganisms in the reaction medium using exhaust gas and a pH adjuster introduced into the reactor, and fermenting to prepare a mixed fermentation broth; and purifying ethanol from the mixed fermentation broth, wherein the exhaust gas containing carbon monoxide includes converter gas (LDG), and a preprocessing unit, a gas flowmeter, an oxygen measuring unit and a carbon monoxide measuring unit are installed in the gas inlet line. The preprocessing unit includes a gas boosting unit, an oxygen removal unit, and a sulfur removal unit, and the preprocessing unit, gas flowmeter, oxygen measuring unit, carbon monoxide measuring unit, pH probe, first input line, and rotation unit are each controlled by a control unit. is electrically connected to and controlled, and when the oxygen concentration in the exhaust gas measured by the oxygen measuring means during biofuel production exceeds a predetermined numerical range, the control unit controls the preprocessing unit to reduce the exhaust gas flow rate or to increase the amount of oxygen removal increase, and when the measured oxygen concentration in the exhaust gas is less than a predetermined numerical range, the pH probe measures the pH inside the reactor, and when the pH value inside the reactor is outside the predetermined numerical range, the controller controls 1 The input line is controlled to increase the pH input agent input, or the exhaust gas flow rate is increased by controlling the pretreatment unit.

In one embodiment, the oxygen measuring means and the carbon monoxide measuring means may each include a tunable diode laser spectrometer (TDLS).

In one embodiment, the predetermined oxygen concentration in the exhaust gas may be 5 to 15 ppm.

In one embodiment, the preset pH range may be 4.5 to 5.5.

In one embodiment, when the pH value inside the reactor is less than 4.5, the control unit controls the first input line to increase the pH input agent input amount, and when the pH value inside the reactor exceeds 5.5, the control unit controls the pH value inside the reactor. The exhaust gas flow rate may be increased by controlling the preprocessing unit.

In one embodiment, when the pH value inside the reactor is less than 4.5, the control unit controls the rotating means to increase the number of rotations of the motor, thereby increasing the mixing speed of the pH input agent and exhaust gas.

In one embodiment, a discharge line through which unreacted exhaust gas from the reactor is discharged may be provided at the top of the reactor.

When the biofuel production method of the present invention is applied, the amount of oxygen (O ₂ ) inflow is minimized, the decrease in biofuel productivity due to the flow rate and composition variation of carbon monoxide-containing gas is minimized, and productivity and economic efficiency can be excellent.

1 shows a biofuel manufacturing method according to one embodiment of the present invention.
2 shows a biofuel production apparatus according to one embodiment of the present invention.
Figure 3 shows the control logic of the biofuel manufacturing apparatus according to one embodiment of the present invention.

Hereinafter, the present invention will be described in detail. At this time, in describing the present invention, if it is determined that a detailed description of a related known technology or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

In addition, the terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of the user or operator, so the definitions should be made based on the content throughout this specification describing the present invention.

Bio fuel manufacturing method

One aspect of the present invention relates to a method for producing biofuels. 1 shows a biofuel manufacturing method according to one embodiment of the present invention. Referring to FIG. 1, the biofuel manufacturing method includes (S10) preparing a mixed fermented liquid; and (S20) an ethanol purification step. More specifically, the biofuel production method includes (S10) culturing and fermenting anaerobic microorganisms in the reaction medium using exhaust gas and a pH regulator introduced into the reactor to prepare a mixed fermentation broth; and (S20) purifying ethanol from the mixed fermentation broth.

Hereinafter, the biofuel manufacturing method according to the present invention will be described in detail step by step.

(S10) Mixed fermentation liquid manufacturing step

This step is a step of preparing a mixed fermentation broth by culturing and fermenting the flue gas and the pH adjusting agent introduced into the reactor in a reaction medium.

2 shows a biofuel production apparatus according to one embodiment of the present invention. Referring to FIG. 2, the biofuel production apparatus 1000 includes a gas inlet line 100 into which exhaust gas containing carbon monoxide flows, a pH probe 110 provided on top of the gas inlet line 100, and a pH probe ( 110), including a first input line 120 into which a pH adjusting agent is introduced, and having a reaction medium (not shown) containing anaerobic microorganisms therein (200); and a rotating means 130 provided on one side of the bottom of the reactor 200. The biofuel production method of the present invention is carried out using the biofuel production device.

The exhaust gas containing carbon monoxide includes converter gas (LDG). In one embodiment, the converter gas may include 45 to 70 vol% of carbon monoxide (CO) and 0.5 to 2 vol% of hydrogen (H ₂ ). When the converter gas is included, production and efficiency may be excellent when manufacturing biofuels such as ethanol.

In one embodiment, the anaerobic microorganism may be a carboxydotrophic microorganism. Specifically, the anaerobic microorganisms may be microorganisms that obtain energy and carbon from carbon monoxide (CO). In one embodiment, the anaerobic microorganism is Morella, Clostridia , Ruminococcus , Acetobacterium , Eubacterium , Butyribacterium , Oxobacter ( Oxobacter ), Methanosarcina ( Methanosarcina ) and Desulfotomaculum ( Desulfotomaculum ) may include one or more of the genera.

In one embodiment, the exhaust gas is contacted with the anaerobic microorganisms in a reaction medium, cultured and fermented to prepare a mixed fermentation broth, and the pH adjuster adjusts the pH of the reaction medium to a range of 4.5 to 5.5 To improve biofuel productivity included in For example, the pH of the reaction medium may be adjusted to 5.0. For example, the pH adjusting agent may include ammonium hydroxide (NH ₄ OH).

In one embodiment, the pH probe 110 can measure the pH of the reaction medium. In addition, in the present invention, the pH probe 110 is inserted into the pH probe 110 as shown in FIG. It is formed below the first input line 120 to be.

When the pH probe 110 is formed at the bottom of the first input line 120, it is possible to quickly grasp the pH change according to the CO content of the exhaust gas, so that the pH of the internal reaction medium can be measured as an error even when the exhaust gas flow rate is not constant. The productivity of ethanol can be excellent by controlling without.

The reaction medium may further include additives commonly used in the art. In addition, the reactor is maintained under anaerobic conditions and can be cultured and fermented under conventional conditions.

Conventional reactors of the present invention can be used. For example, it may be a tower type suitable for contacting a reaction medium for culturing anaerobic microorganisms and the exhaust gas, but is not limited thereto.

(S20) ethanol purification step

This step is a step of purifying ethanol from the mixed fermentation broth. In one embodiment, the mixed fermentation broth may include ethanol and acetic acid (or acetate ion). When the acetic acid content increases, the pH of the culture medium may decrease, and in this case, since the ethanol yield decreases, the pH of the reactor culture medium may be adjusted by introducing a pH adjuster through the input line.

Ethanol contained in the mixed fermentation broth can be purified by a conventional method. For example, anaerobic microorganisms may be separated by filtering the mixed fermentation broth through a cell separator, etc., and ethanol may be purified using a distillation device or an adsorption filtering device.

Referring to FIG. 2, a discharge line 210 through which unreacted exhaust gas is discharged may be provided at the top of the reactor 200.

Referring to FIG. 2, the preprocessing unit 10, the gas flowmeter, the oxygen measuring unit and the carbon monoxide measuring unit are sequentially connected to the gas inlet line 100 of the biofuel production device.

Although not shown in FIG. 2, the preprocessing unit 10 includes a gas boosting unit, an oxygen removing unit, and a sulfur removing unit. For example, the gas boosting unit, the oxygen removing unit, and the sulfur removing unit may be sequentially connected.

In one embodiment, the preprocessing unit 10, the gas flow meter 20, the oxygen measuring means 30, the carbon monoxide measuring means 40, the pH probe 110, the first input line 120 and the rotating means 130 are Each control unit 300 is electrically connected and controlled.

The gas boosting unit, the oxygen removing unit, and the sulfur removing unit may be sequentially formed based on the traveling direction of the exhaust gas introduced into the gas inlet line.

Figure 3 shows the control logic of the biofuel manufacturing apparatus according to one embodiment of the present invention. Referring to FIG. 3, when the oxygen concentration in the exhaust gas measured by the oxygen measuring unit exceeds a predetermined numerical range during biofuel production, the control unit controls the preprocessing unit to reduce the exhaust gas flow rate or increase the oxygen removal amount. When the measured oxygen concentration in the exhaust gas is less than a predetermined numerical range, the pH probe measures the pH inside the reactor, and when the pH value inside the reactor is outside the predetermined numerical range, the control unit first The input line is controlled to increase the pH input agent input, or the exhaust gas flow rate is increased by controlling the pretreatment unit.

In one embodiment, the oxygen measuring means 30 and the carbon monoxide measuring means 40 may each include a tunable diode laser spectrometer (TDLS). The tunable diode laser analyzer includes a laser emitting unit and a laser receiving unit, and can analyze in real time the oxygen concentration and carbon monoxide concentration of the exhaust gas introduced into the gas inlet line, so that process automation efficiency can be excellent.

In one embodiment, when the oxygen concentration in the exhaust gas exceeds a predetermined numerical range, the control unit may control the gas boosting unit of the preprocessing unit to decrease the exhaust gas flow rate or increase the oxygen removal amount by controlling the oxygen removal unit.

In one embodiment, when the oxygen concentration in the exhaust gas is below a predetermined range, the pH value of the reaction medium inside the reactor is controlled.

When the flow rate and carbon monoxide concentration of the exhaust gas are analyzed in real time and the flow rate and carbon monoxide concentration of the exhaust gas increase, the reaction rate in the reaction medium may increase and the concentration of acetic acid may increase. At this time, when the pH is lowered from the proper pH, it can be adjusted by introducing a pH adjusting agent such as ammonium hydroxide. In this case, if ammonium hydroxide is not mixed quickly, an excessive amount is added and the pH increases excessively, which may rather hinder the growth of microorganisms. The position of the pH probe is important to increase the mixing speed of the pH adjusting agent. That is, the position of the pH probe is installed before the first input line in consideration of the direction of the exhaust gas fluid to determine the complete mixing state. In addition, when the amount of sodium hydroxide is increased due to a drop in pH, the rotation speed of the motor is increased to increase the mixing speed to adjust the pH.

For example, when the measured oxygen concentration in the exhaust gas is less than a predetermined numerical range, the pH probe measures the pH inside the reactor, and when the pH value inside the reactor is out of a predetermined numerical range, the controller controls 1 The input line is controlled to increase the pH input agent input, or the exhaust gas flow rate is increased by controlling the pretreatment unit.

When the flow rate of the flue gas fluctuates greatly, the oxygen removal efficiency of the oxygen removal unit may decrease, and thus the oxygen content in the reactor may increase. However, when the control unit compares the oxygen concentration measured in real time with a preset numerical range as described above, the amount of oxygen that can adversely affect anaerobic microorganisms inside the reactor can be minimized, resulting in excellent biofuel productivity. there is.

In one embodiment, the predetermined oxygen concentration in the exhaust gas may be 5 to 15 ppm. When the above conditions are controlled, the amount of oxygen that can adversely affect anaerobic microorganisms inside the reactor can be minimized, so that biofuel productivity can be improved. For example, the predetermined oxygen concentration in exhaust gas may be 10 ppm.

In one embodiment, the preset pH range may be 4.5 to 5.5. In one embodiment, when the pH value inside the reactor is less than 4.5, the control unit controls the first input line to increase the pH input agent input amount, and when the pH value inside the reactor exceeds 5.5, the control unit controls the pH value inside the reactor. The exhaust gas flow rate may be increased by controlling the preprocessing unit.

In one embodiment, when the pH value inside the reactor is less than 4.5, the control unit controls the rotating means to increase the number of rotations of the motor, thereby increasing the mixing speed of the pH input agent and exhaust gas. As described above, when the mixing speed is increased, the growth of microorganisms may be prevented, and thus biofuel productivity may be excellent.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention by this in any sense.

Example

Biofuel was produced using a biofuel manufacturing apparatus as shown in FIG. 2 below. Specifically, the exhaust gas (converter gas (LDG) is introduced through the gas inlet line 100, the pH adjuster (ammonium hydroxide) is introduced into the reactor 200 through the first input line 120, and the introduced Anaerobic microorganisms (carboxydotrophic microorganisms) were cultured and fermented in the reaction medium in the reaction medium using flue gas and pH adjusting agent in a conventional manner to prepare a mixed fermentation broth. Peracetic acid was separated to purify ethanol.At this time, unreacted flue gas inside the reactor 200 was discharged to the outside of the device through a discharge line 210.

At this time, the oxygen measuring means 30 and the carbon monoxide measuring means 40 each used a tunable diode laser analyzer (TDLS).

When the oxygen concentration in the exhaust gas measured by the oxygen measuring means 30 exceeds 10 ppm during biofuel production, the control unit 300 controls the gas boosting unit or the oxygen removal unit of the preprocessing unit 10 to reduce the exhaust gas flow rate, The oxygen concentration in the exhaust gas was reduced by increasing the amount of oxygen removal.

Then, the oxygen concentration in the exhaust gas measured by the oxygen measuring means was measured to be 10 ppm or less, and as a result of measuring the pH inside the reactor 200 by the pH probe 110, it was measured to be less than pH 4.5, and the control unit 300 1 The input line 120 was controlled to increase the amount of pH input agent. In addition, the control unit 300 controls the rotating means 130 to increase the number of rotations of the motor, thereby increasing the mixing speed of the pH injection agent and the exhaust gas to uniformly mix them, thereby increasing the pH to 5.0.

Table 1 below shows changes in the flow rate of converter gas (LDG) generated in the integrated steelmaking process, and Table 2 is a table showing the composition of the converter gas.

Referring to Tables 1 and 2, in the case of flue gas (converter gas) generated as a by-product gas of the integrated steelmaking process, the deviation of flow rate and carbon monoxide content is severe, making it difficult to remove oxygen removal efficiency in the flue gas, and biofuel There was a difficult problem in adjusting the pH of the reaction medium during manufacture. However, when the biofuel production method according to the present invention is applied, the oxygen content of the exhaust gas, the carbon monoxide content, and the pH inside the reactor are analyzed in real time, and the oxygen content and pH conditions inside the reactor are adjusted to maintain the optimum microbial fermentation conditions It was found that the effect was excellent.

Simple modifications or changes of the present invention can be easily performed by those skilled in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

10: preprocessing unit 20: gas flow meter
30: oxygen measuring means 40: carbon monoxide measuring means
100: gas inlet line 110: pH probe
120: first input line 130: rotation means
200: reactor 210: discharge line
300: control unit 1000: biofuel manufacturing device

Claims (7)

A gas inlet line into which exhaust gas containing carbon monoxide is introduced, a pH probe provided above the gas inlet line, and a first input line provided above the pH probe and into which a pH adjusting agent is introduced, including anaerobic microorganisms therein A reactor equipped with a reaction medium to; And a rotation means provided on one side of the lower part of the reactor; a biofuel manufacturing method using a biofuel manufacturing apparatus including,
preparing a mixed fermentation broth by culturing and fermenting anaerobic microorganisms in the reaction medium using flue gas and a pH regulator introduced into the reactor; and
Purifying ethanol from the mixed fermentation broth; including,
The exhaust gas containing carbon monoxide includes converter gas (LDG),
A preprocessing unit, a gas flow meter, an oxygen measuring unit and a carbon monoxide measuring unit are sequentially connected to the gas inlet line,
The preprocessing unit includes a gas boosting unit, an oxygen removing unit and a sulfur removing unit,
The preprocessing unit, the gas flowmeter, the oxygen measuring means, the carbon monoxide measuring means, the pH probe, the first input line, and the rotating means are electrically connected to and controlled by the control unit, respectively.
When the oxygen concentration in the exhaust gas measured by the oxygen measuring unit during biofuel production exceeds a predetermined numerical range, the control unit controls the preprocessing unit to reduce the exhaust gas flow rate or increase the oxygen removal amount,
When the measured oxygen concentration in the exhaust gas is less than or equal to a predetermined numerical range, the pH probe measures the internal pH of the reactor,
When the pH value inside the reactor is out of a predetermined numerical range, the control unit controls the first input line to increase the pH input agent input or controls the pretreatment unit to increase the exhaust gas flow rate. manufacturing method.
According to claim 1,
The oxygen measuring means and the carbon monoxide measuring means biofuel manufacturing method, characterized in that each comprises a tunable diode laser spectrometer (Tunable Diode Laser Spectrometer, TDLS).
According to claim 1,
Biofuel production method, characterized in that the oxygen concentration in the predetermined exhaust gas is 5 ~ 15ppm.
According to claim 1,
The predetermined pH value range is a biofuel manufacturing method, characterized in that 4.5 ~ 5.5.
According to claim 4,
When the pH value inside the reactor is less than 4.5, the control unit controls the first input line to increase the pH input agent input amount,
When the pH value inside the reactor is greater than 5.5, the control unit controls the pre-processing unit to increase the exhaust gas flow rate.
According to claim 5,
When the pH value inside the reactor is less than 4.5, the control unit controls the rotation means to increase the number of rotations of the motor, thereby increasing the mixing speed of the pH input agent and exhaust gas.
According to claim 1,
Biofuel production method, characterized in that the upper part of the reactor is provided with a discharge line through which unreacted exhaust gas is discharged from the reactor.

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