Method and a Device for Cleaning a Gas

Abstract

The invention relates to a method for cleaning a gas, comprising the step of guiding said gas to be cleaned through a supply line and contacting said gas with a liquid and a step of injecting the liquid into the gas flow under pressure over a complete flow area of said supply line. The method is characterized in that the gas to be cleaned is fed into the gas cleaning compartment from a gas supply line, said gas cleaning compartment having a peripheral wall, and in that the gas cleaning compartment at a downstream position of the gas supply line is provided with at least one injection nozzle provided in the peripheral wall for injecting the liquid into the gas cleaning compartment and against an opposite wall part, said method further comprising the step of discharging the liquid and the contaminants contained therein via the wall of the gas cleaning compartment. The invention also relates to a device for performing the method.

Claims

1. A method for cleaning a gas, comprising the step of guiding said gas to be cleaned through a gas cleaning compartment and contacting said gas with a liquid, the method comprising the further step of injecting the liquid into a gas flow under pressure over a complete flow area of said gas cleaning compartment for capturing contaminants from said gas flow; characterized in that: the gas to be cleaned is fed into the gas cleaning compartment from a gas supply line, said gas cleaning compartment having a peripheral wall, and in that the gas cleaning compartment at a downstream position of the gas supply line is provided with at least one injection nozzle provided in the peripheral wall for injecting the liquid into the gas cleaning compartment and against an opposite wall part, said method further comprising the step of discharging the liquid and the contaminants contained therein via the peripheral wall of the gas cleaning compartment.

2. The method according to claim 1, comprising the step of injecting the liquid through a slit-shaped nozzle.

3. The method according to claim 1, comprising the step of injecting the liquid through at least two nozzles that are divided along the circumference of the peripheral wall of the gas cleaning compartment.

4. The method according to claim 1, comprising the step of injecting the liquid in at least two layers that substantially completely cover the complete flow area of the gas cleaning compartment.

5. The method according to claim 4, wherein each layer comprises at least one nozzle.

6. The method according to claim 1, wherein the liquid comprises water.

7. The method according to claim 1, wherein the gas supply line has a first diameter and the gas cleaning compartment has a second diameter, wherein the second diameter is larger than the first diameter.

8. The method according to claim 1, comprising the step of vertically in an upward direction feeding the gas to be cleaned through the gas cleaning compartment.

9. The method according to claim 1, comprising the step of feeding the gas to be cleaned through the gas supply line in a direction other than a vertical direction and injecting the liquid into the gas cleaning compartment for contacting the gas flow with the liquid and discharging the liquid via the peripheral wall of the gas cleaning compartment.

10. The method according to claim 1, wherein part of the gas supply line that is positioned inside the gas cleaning compartment as well as the gas cleaning compartment itself are coaxial tubular shapes, wherein the liquid is discharged via an interstitial space between said coaxial tubular shapes.

11. A device for performing a method according to claim 1, comprising a gas cleaning compartment with a gas supply line for feeding a gas to be cleaned into the gas cleaning compartment, said gas cleaning compartment being provided with at least one nozzle for injecting into the gas cleaning compartment a liquid for contacting the gas to be cleaned with the liquid, wherein the device further comprises a discharge for discharging the injected liquid.

12. A device according to claim 11, wherein the gas supply line for feeding the gas to be cleaned has a first diameter, said gas supply line debouching into a gas cleaning compartment with a second diameter, said second diameter being larger than the first diameter, and wherein the device is provided with a nozzle for injecting into the gas cleaning compartment a liquid, wherein the gas cleaning compartment has a wall that extends at least radially outside the gas supply line.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0033] The invention will now be described by means of a drawing. The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more embodiments of the invention and are not to be construed as limiting the invention. In the drawings:

[0034] FIG. 1 a schematic sectional view of a device according an embodiment of the present invention; and

[0035] FIG. 2 a schematic top view of a device according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0036] In the drawings the same parts are referred to by the same reference numerals. However, for ease of understanding the drawing, not all parts that are required for a practical embodiment are shown in the drawing.

[0037] FIG. 1 shows a schematic view of a device 1 for cleaning a gas flow 2. The gas flow 2 is schematically identified by a series or arrows that show a flow direction. The device is comprised of a gas supply line 3 and a gas cleaning compartment 4. In the embodiment as shown in FIG. 1 the gas supply line 3 is shown as a conduit that originates from a burner space 5 with a number of burner nozzles 6 yielding a combustion gas as gas flow 2 containing harmful substances that must be removed from the gas flow 2 in the gas cleaning compartment 4. The gas flow 2 is not limited to such origin but may be obtained from many different sources. It may be obtained from residential areas of a hospital where harmful bacteria and viruses reside in the gas flow 2 and that need to be removed. The gas flow 2 also may originate from factories, farm houses or offices, where the gas flow 2 may comprise dust or fine dust that needs to be removed.

[0038] The gas flow 2 is fed from the gas supply line 3 into space 8 in which nozzles 7 are provided for injecting into the space a liquid 9. Through the nozzles 7 a liquid 9 is injected into space 8 of the gas cleaning compartment 4 forcefully. As a consequence, the gas flow 2 is contacted intimately with the liquid 9. The liquid 9 is preferably injected into space 8 in a flat plane, wherein the flat plane is positioned substantially perpendicular to the flow direction of the gas 2. Where a multiplicity of nozzles is used the liquid 9 flows preferably do not interfere so as to obtain and optimum contact of liquid 9 and gas 2. According to an alternative embodiment the liquid 9 may be injected at an angle with respect to the gas flow direction, i.e. an angle different from perpendicularly, for example an angle of up to 45.

[0039] The injected liquid 9 is preferably injected with sufficient force to obtain an even jet of liquid 9 along the total cross-sectional area of the space 8. Such ensures an optimum contact and a most efficient cleaning.

[0040] The gas cleaning compartment 4, more in particular the space 8 where the piqued is injected, extends until further than the radial dimension of the gas conduit 3. As a consequence, the liquid 9 may flow away without entering the gas conduits 3, when it hits the wall 10 of the gas cleaning compartment 4. Such solution for removal of used liquid 9 is also effective when the gas conduit 3 and the gas cleaning compartment 4 are positioned horizontally, instead of vertically as shown in the figure. Thus, the device 1 comprises a liquid collection device 11 for collecting used liquid 9. Form thereon, the liquid may be dispensed of towards a reservoir 12 for cleaning or reprocessing.

[0041] FIG. 2 gives a schematic perspective view of the device 1. The gas conduit 3 and the gas cleaning compartment 4 can be clearly seen. Furthermore, three burner nozzles 6 are shown, which however are optional. The device 1 comprises three nozzles 7 for liquid, that together cover the gas flow area so as to efficiently treat and clean the gas 2. The covered area is schematically identified by dotted lines. The used liquid flows away through space 13 between the gas conduit 3 and the wall 10 of the gas cleaning compartment 4.

[0042] A test experiment was performed as follows. An amount of gas to be cleaned of 1 m3/sec was fed though a gas conduit with an inner diameter of 20 cm. The gas cleaning compartment has an inner diameter of 25 cm. The gas cleaning compartment comprises three Steinen (trademark) water nozzles each providing a throughput of about 12 l/hr at a pressure of 20 psi. The spray angle of the nozzles is about 60.

[0043] According to a first experiment, the water comprised tap water without any additives. A second experiment was performed with water comprising a slight addition of CaCO.sub.3 for neutralizing any small amount of acid components in the gas. The gas to be cleaned comprised, among others, NO.sub.2 and SO.sub.2.

EXPERIMENT I

[0044] Concentrations of NO.sub.2 and SO.sub.2 were reduced to below the measuring limitations of the measuring equipment. Solid particles present in the gas were not visible by the eye and were all removed by the water.

[0045] Without any addition of water in the gas cleaning compartment the concentrations amounted NO.sub.2 57 ppm and SO.sub.2 250 ppm.

[0046] When injecting liquid into the gas cleaning compartment the concentrations of NO.sub.2 and SO.sub.2 were not detectable.

[0047] The liquid's pH was substantially lower after having performed the test experiment, from pH 7 to pH<5.

EXPERIMENT II

[0048] Concentrations of NO.sub.2 and SO.sub.2 were reduced to below the. The amount of solid particles present in the gas were reduced substantially on the eye, after treatment of the gas with the liquid and were not visible anymore, thus the solid particles were removed by the water.

[0049] Without addition of any liquid into the gas cleaning compartment the concentration amounted to NO.sub.2 57 ppm and SO.sub.2 250 ppm.

[0050] When injecting a liquid comprising CaCO.sub.3 into the gas cleaning compartment the concentrations of NO.sub.2 and SO.sub.2 were not detectable.

[0051] The pH of the liquid after the treatment was substantially reduced from pH 9 to about pH 7. The addition of CaCO.sub.3 to the liquid had no noticeably influence on the removal of harmful substances but yielded a liquid flow that could be disposed of without any further processing.

EXPERIMENT III

[0052] A further embodiment of the invention provides for a combination of the invention with an additional burner at a position upstream the gas cleaning compartment 4. Preferably, a burner using HHO is used.

[0053] It has shown that such HHO burner has a positive influence on the removal of solid particles in the gas. On the eye, the solid particles that are present in the gas are completely removed after treatment of the gas with the HHO burner and the liquid and are thus fully removed.

[0054] In the test three nozzle burners were used of the kind Delavan Siphon nr. 4 (trademark), with the addition of HHO in an amount of 10 l/min.

[0055] The burners increased the amount of NOx in the gas to be cleaned, but this was removed from the gas by means of the liquid treatment according to the invention to a value less than detectable.

[0056] The device according to the present invention can be used suitably for cleaning gasses that comprise a large amount of solid particles. Examples thereof are flue gasses from diesel engines, especially ships diesel engines. Also, cleaning of flue gasses from power plants, amongst which coal fired and gas fired power plants, and municipal waste incinerators can be performed suitably with the device according to the present invention. All solid particles, like fly ash, are removed efficiently and effectively with the device and method according to the present invention. Furthermore, water soluble substances like sulfur oxides are affectively removed. Thus, the treated gasses can be discharge into the environment directly without any after treatment thereof.

[0057] The invention is not limited to the embodiments as described above and as shown in the drawing. The invention is limited only by the appending claims.

[0058] The invention also covers all combinations of features and measures that are described in this text independently of each other.

[0059] Although the invention has been described in detail with particular reference to these embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference.