System and method for flue gas treatment

The present invention discloses a system for flue gas treatment, wherein the provided system comprises a quench module, a first control module, a filter collecting module, a wet scribing module and a regeneration module. In this system, parts of the particles contained in flue gas are removed in the quench module and the wet scribing module by a first scrubbing solution, and then in wet scribing module a second scrubbing liquid containing particles is formed. Next, the second scrubbing solution is treated in the regeneration module to form a third scrubbing solution, wherein the third scrubbing solution is then fed back to the quench module and/or the wet scrubbing module to substitute the first scrubbing solution for repeating what originally performed via the first scrubbing solution. Furthermore, this invention discloses a method for flue gas treatment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under the Paris Convention to Taiwan application No. 093115906 filed on Jun. 3, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally related to flue gas treatment, and more particularly to flue gas treatment utilizing a recovery scrubbing solution.

2. Description of the Prior Art

Incineration is one of the best methods of reducing the volume and hazard of organic hazardous wastes. Through incineration, more than 90 percent of the volume of the original waste is typically reduced. However, there is no 100 percent efficient process, including incineration. Products of Incomplete Combustion (PICs) may be formed at trace concentrations during incinerations of both hazardous and nonhazardous wastes. PICs are organic compounds which are formed during partial combustion due to incomplete mixing, insufficient time, or insufficiently high temperatures, and are not completely destroyed. In operation, PICs and other byproduct of incineration should be removed by the air pollution control equipment to avoid secondary pollution for environment. However, to improve the process as a whole, the amounts of PICs should be decreased by improving the incineration efficiency, but not to depend on post air pollution control treatment.

Wet scrubber, dry sorbent injection and semi-dry sorbent injection are current common air pollution control equipments, wherein wet scrubber is more preferable for its much lower price. Nevertheless, for the wet scrubber, waste scrubbing water treatment is a big issue. Currently, a commercial solution is that wastewater treatment plant supports incineration in a comprehensive waste management system. Combustible constituents are burned at incinerators; soluble constituents and suspended particulates in wastewater are treated at wastewater treatment plants, so as to meet the National Effluent Standard. Therefore, a new system for flue gas treatment is still needed corresponding to both economic effect and utilization in industry.

SUMMARY OF THE INVENTION

In accordance with the present invention, new system and method for flue gas treatment are provided. These system and method can meet the requirement of low cost and high operation efficiency.

One object of the present invention is to employ a recovery scrubbing solution in a scrubbing tower, incinerating apparatus, or cooling apparatus (for example: a quench tower), so as to reduce the amount of waste water and to supply cooling water as well. Moreover, with only a few modifications this invention can be applied to the present small and medium capacity incinerators. Therefore, this present invention does have the economic advantages for industrial applications.

Accordingly, the present invention discloses a system for flue gas treatment, wherein the provided system comprises a quench module, a first control module, a filter collecting module, a wet scribing module and a regeneration module. In this system, parts of the particles contained in flue gas are removed in the quench module and the wet scribing module by a first scrubbing solution, and then in wet scribing module a second scrubbing liquid containing particles is formed. Next, the second scrubbing solution is treated in the regeneration module to form a third scrubbing solution, wherein the third scrubbing solution is then fed back to the quench module and/or the wet scrubbing module to substitute the first scrubbing solution for repeating what originally performed via the first scrubbing solution. Furthermore, this invention discloses a method for flue gas treatment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

What is probed into the invention is system and method for flue gas treatment. Detailed descriptions of the production, structure and elements will be provided in the following in order to make the invention thoroughly understood. Obviously, the application of the invention is not confined to specific details familiar to those who are skilled in flue gas treatment. On the other hand, the common elements and procedures that are known to everyone are not described in details to avoid unnecessary limits of the invention. Some preferred embodiments of the present invention will now be described in greater detail in the following. However, it should be recognized that the present invention can be practiced in a wide range of other embodiments besides those explicitly described, that is, this invention can also be applied extensively to other embodiments, and the scope of the present invention is expressly not limited except as specified in the accompanying claims.

In a first embodiment of the present invention, a method for flue gas treatment is provided. First of all, performing a quenching process125by a first scrubbing solution110to decrease the temperature of a first flue gas120to a first temperature, and to remove a plurality of first flue gas particles with a first diameter from the first flue gas120, wherein the first temperature ranges from 150to 190, and the first diameter is larger than 50 μm. Next, performing a filter collecting process135to remove a plurality of second flue gas particles with a second diameter from the first flue gas120with the first temperature, through which to form a second flue gas140with the first temperature, wherein the filter collecting process135further comprises a fabric filtering process, the second diameter is larger than 30 μm, and the second temperature ranges from 40to 60. Afterwards, performing a wet scrubbing process145by the first scrubbing solution110to decrease the first temperature of the second flue gas140to a second temperature, and to remove a plurality of third flue gas particles with a third diameter, larger than 10 μm, from the second flue gas140, whereupon a second scrubbing solution150is formed from the first scrubbing solution110, and then a third flue gas160is formed. After the wet scrubbing process145, performing a regeneration process165to treat the second scrubbing solution140to form a third scrubbing solution170. Finally, feeding the third scrubbing solution170back to substitute the second scrubbing solution150for repeating the quenching process125and the wet scrubbing process145which are originally performed via the first scrubbing solution110. If the first and second flue gases120,140contain acid matter, the wet scrubbing process145is performed to remove the acid matter. On the other hand, the above-mentioned quenching process125further comprises a dilution step to assist in decreasing the temperature of the first flue gas120to the first temperature, in an effort to reduce the amount of the second scrubbing solution150produced.

In this embodiment, the regeneration process165further comprises a particle-removing process and a cooling process, wherein the particle-removing process is performed to remove a plurality of particles contained in the second scrubbing solution150, through which to fabricate the third scrubbing solution170with a third temperature. In detail, the particle-removing process further comprises performing a gravity settling step to remove a plurality of fist scrubbing solution particles with a fourth diameter, larger than 10 μm, from the second scrubbing solution150; utilizing centrifugal force to remove a plurality of second scrubbing solution particles with a fifth diameter, larger than 10 μm, from the second scrubbing solution150; and performing a screen step to remove a plurality of third scrubbing solution particles with a sixth diameter, larger than 5 μm, from the second scrubbing solution150. Next, the cooling process is performed to decrease the third temperature of the third scrubbing solution170to a fourth temperature, through which the third scrubbing solution170with the fourth temperature is formed, wherein the fourth temperature is lower than 40. Moreover, the third scrubbing solution170with the third temperature is applicable in the quenching process125, and the third scrubbing solution170with the fourth temperature is applicable in both the wet scrubbing process145and the quenching process125. On the other hand, if the second scrubbing solution150contains acid matter, the regeneration process165further comprises a neutralization step to neutralize the acid matter, so as to fabricate the third scrubbing solution170with a specific pH value ranging from pH7 to pH9.

In a second embodiment of the present invention, there is provided a system for flue gas treatment, which comprises a quench module210, a first control module220for adjusting the flow rate of the first scrubbing solution110into the quench module210, a filter collecting module230, a wet scrubbing module240and a regeneration module. In detail, the quench module210is used to receive a first flue gas120, decrease the temperature of the first flue gas120to a first temperature via a first scrubbing solution110, and remove a plurality of first flue gas particles with a first diameter from the first flue gas120Next, the filter collecting module230is used to remove a plurality of second flue gas particles with a second diameter from the first flue gas120with the first temperature, whereupon a second flue gas140with the first temperature is formed, and the filter collecting module further comprises a fabric filter. Furthermore, the wet scrubbing module240is used to decrease the first temperature of the second flue gas140to a second temperature via the first scrubbing solution110, and to remove a plurality of third flue gas particles with a third diameter from the second flue gas140, whereupon a second scrubbing solution150is formed. Finally, the regeneration module250is used to treat the second scrubbing solution150to form a third scrubbing solution170, wherein the third scrubbing solution170is then fed back to the quench module210and the wet scrubbing module240to substitute the first scrubbing solution110for repeating what originally performed via the first scrubbing solution110.

In this embodiment, the first control module220further comprises: a first flow rate detecting device220A to detect the flow rate of said first flue gas and generate a first flow rate signal; a first humidity detecting device220B to detect the humidity of said first flue gas and generate a first humidity signal; a first temperature detecting220C device to detect the temperature of said first flue gas and generate a first temperature signal; a central processing device220D to receive said first flow rate signal, said first humidity signal and said first temperature signal, and to generate an instant first control signal; and a first control valve220E to receive said first control signal, lead said first scrubbing solution110into said quench module210and adjust the amount of said first scrubbing solution110. Furthermore, said first control module220further comprises a dilution apparatus to assist in decreasing the temperature of said first flue gas120and reduce the amount of said second scrubbing solution produced150. Additionally, said dilution apparatus further comprises: a second humidity detecting device220F to detect the humidity of a cooling gas and generate a second humidity signal; a second temperature detecting device220G to detect the temperature of said cooling gas and generate a second temperature signal; said first central processing device220D to receive said second humidity signal and said second temperature signal, and combine with said first flow rate signal, said first humidity signal and said first temperature signal, to generate an instant second control signal; and a second control valve220H to receive said second control signal, lead said cooling gas into said filter collecting module230and adjust the amount of said cooling gas.

In this embodiment, the regeneration module250further comprises a particle-removing apparatus250A and a cooling apparatus250B, wherein the particle-removing apparatus250A is used to remove a plurality of particles contained in said second scrubbing solution150, through which to fabricate said third scrubbing solution170with a third temperature. In detail, the particle-removing apparatus250A further comprises a gravity settling tank250A1, a hydrocyclone250A2and a screen250A3, wherein the gravity settling tank250A1is used to remove a plurality of fist scrubbing solution particles with a fourth diameter from said second scrubbing solution150. Next, a hydraulic cyclone250A2is used to remove a plurality of second scrubbing solution particles with a fifth diameter from said second scrubbing solution150by utilizing centrifugal force. Moreover, a screen250A3to remove a plurality of third scrubbing solution particles with a sixth diameter from said second scrubbing solution150. On the other hand, the cooling apparatus250B is used to decrease said third temperature of said third scrubbing solution170to a fourth temperature, through which said third scrubbing solution170with said fourth temperature is formed. The cooling apparatus250B further comprises a heat exchanger250B1and a cooling tower250B2, wherein the heat exchanger250B1is used to decrease said third temperature of said third scrubbing solution170to said fourth temperature by use of a cooling agent with a fifth temperature, in the mean time said fifth temperature of said cooling agent is increased to a sixth temperature. Next, the cooling tower250B2is used to decrease said sixth temperature of said cooling agent to said fifth temperature, and feed back said cooling agent with said fifth temperature to said heat exchanger250b1for repeating use. Besides, if the second scrubbing solution150contains acid matter, the regeneration module250further comprises a neutralization apparatus250C to neutralize the acid matter, wherein the neutralization apparatus250C comprises: a pH value detector250C1to detect the pH value of said second scrubbing solution150and generate a pH value signal; a second central processing device250C2to receive said pH value signal and generate an instant third control signal; and at least one chemical agent tanks250C3to receive said third control signal and provide said chemical agent to adjust said pH value of said second scrubbing solution150.

In a third embodiment of the present invention, there is provided a system for flue gas treatment, which comprises: a quench tower310to receive a first flue gas, decrease the temperature of said first flue gas to a first temperature via a first scrubbing solution, and remove a plurality of first flue gas particles with a first diameter from said first flue gas; a fabric filter330to remove a plurality of second flue gas particles with a second diameter from said first flue gas with said first temperature, whereupon a second flue gas with said first temperature is formed; a first control module320comprising a first flow rate detecting device320A to detect the flow rate of said first flue gas, a first humidity detecting device320B to detect the humidity of said first flue gas, a first temperature detecting device320C to detect the temperature of said first flue gas, a central processing device320D, a first control valve320E, a second humidity detecting device320F to detect the humidity of a cooling gas, a second temperature detecting device320G to detect the temperature of said cooling gas and a second control valve320H, wherein said first central processing device320D receives a first flow rate signal generated from said first flow rate detecting device320A, a first humidity signal generated from said first humidity detecting device320B, a first temperature signal generated from said first temperature detecting device320C, a second humidity signal generated from said second humidity detecting device320F and a second temperature signal generated from said second temperature detecting device320G, and generates an instant first and second control signals, whereupon said first control valve320E receives said first control signal to lead said first scrubbing solution110into said quench tower310and adjust the amount of said first scrubbing solution110, and said second control valve320H receives said second control signal to lead said cooling gas into said fabric filter330and adjust the amount of said cooling gas; a wet scrubbing tower340to decrease said first temperature of said second flue gas140to a second temperature via said first scrubbing solution110, and to remove a plurality of third flue gas particles with a third diameter from said second flue gas140, whereupon a second scrubbing solution150is formed; and a regeneration module350to treat said second scrubbing solution150to form a third scrubbing solution170, wherein said third scrubbing solution170is then fed back to said quench tower310and said wet scrubbing tower340to substitute said first scrubbing solution110for repeating what originally performed via said first scrubbing solution110.

In this embodiment, the regeneration module350further comprises: a gravity settling tank350A to remove a plurality of fist scrubbing solution particles with a fourth diameter from said second scrubbing solution150; a neutralization apparatus350B to neutralize the acid matter contained in said second scrubbing solution150; a hydrocyclone350C to remove a plurality of second scrubbing solution particles with a fifth diameter from said second scrubbing solution150by utilizing centrifugal force; a screen350D to remove a plurality of third scrubbing solution particles with a sixth diameter from said second scrubbing solution150; a heat exchanger350E to decrease said third temperature of said third scrubbing solution to said fourth temperature by use of a cooling agent with a fifth temperature, in the mean time said fifth temperature of said cooling agent is increased to a sixth temperature; a cooling tower350F to decrease said sixth temperature of said cooling agent to said fifth temperature, and feed back said cooling agent with said fifth temperature to said heat exchanger350E for repeating use. On the other hand, said neutralization apparatus350B further comprises: a pH value detector350B1to detect the pH value of said second scrubbing solution and generate a pH value signal; a second central processing device350B2to receive said pH value signal and generate an instant third control signal; and at least one chemical agent tanks350B3to receive said third control signal and provide said chemical agent to adjust said pH value of said second scrubbing solution150.

In the above preferred embodiments, the present invention employs a recovery scrubbing solution in a scrubbing tower, incinerating apparatus, or cooling apparatus (for example: a quench tower), so as to reduce the amount of waste water and to supply cooling water as well. Moreover, with only a few modifications this invention can be applied to the present small and medium capacity incinerators. Therefore, this present invention does have the economic advantages for industrial applications.

To sum up, the present invention discloses a system for flue gas treatment, wherein the provided system comprises a quench module, a first control module, a filter collecting module, a wet scribing module and a regeneration module. In this system, parts of the particles contained in flue gas are removed in the quench module and the wet scribing module by a first scrubbing solution, and then in wet scribing module a second scrubbing liquid containing particles is formed. Next, the second scrubbing solution is treated in the regeneration module to form a third scrubbing solution, wherein the third scrubbing solution is then fed back to the quench module and/or the wet scrubbing module to substitute the first scrubbing solution for repeating what originally performed via the first scrubbing solution. Furthermore, this invention discloses a method for flue gas treatment.

Obviously many modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the present invention can be practiced otherwise than as specifically described herein. Although specific embodiments have been illustrated and described herein, it is obvious to those skilled in the art that many modifications of the present invention may be made without departing from what is intended to be limited solely by the appended claims.