JPH02207812A - Apparatus for continuously reducing concentration of carbon monoxide and other harmful waste - Google Patents

Abstract

PURPOSE: To impart a high pressure in an exhaust manifold of a wide range of diameter and a high discharge flow rate ratio to the apparatus by selecting the number of parallel and coaxial corona discharge tubes in a system and the diameter thereof. CONSTITUTION: Electrically insulating materials 4 are mounted at the individual discharge tubes to insulate two electrodes 1 and 2 from each other and further two blocks are formed. The one thereof is mounted by a flange and an auxiliary pipe to the exhaust manifold of an automobile. One of the supplying members 3 of the high-voltage electrode 1 is connected to a high-voltage source 6 via a resistor 5 connected to each of the discharge tubes. The resistor 5 obtains balance with respect to electric discharge combustion and has a stable function. The corona discharge decreases the concn. of carbon monoxide as well as other effluents, such as smoke and soot, in the presence of steam. The apparatus is effective for application to small-sized motorcycles and the chimneys of factories.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention solves the problem of reducing environmental pollution due to harmful emissions from various sources, in particular - reducing the concentration of carbon oxides. . Apart from this, other harmful substances such as nitrogen oxides (NOx), hydrocarbons (C1,),
Particles of lead compounds, both solid and liquid, also cause environmental pollution.

PRIOR ART AND THE PROBLEM TO BE SOLVED BY THE INVENTION On an industrial scale, harmful gas emissions are particularly sought to be prevented by means of various separators. The main means aimed at reducing pollutant concentrations in road traffic are directed to the structural adaptation of internal combustion engines to burn such substances immediately in the exhaust manifold. This can be achieved by applying thermal and catalytic reactors as well as by using electrical discharges.

Czechoslovak National Inventor Certificate No. 178.566 describes a process for reducing the concentration of polycyclic aromatic hydrocarbons in exhaust gases by introducing them into a coaxially arranged corona discharge and mixing the gases with pure air. Disclosed. This process is based on the so-called electron wind and the oxidation of the aromatic bonds of polycyclic aromatic hydrocarbons, with the formation of oxidation products. However, this process requires -carbon oxide (Co),
There has been a failure to completely treat nitrogen oxides (NOX) and lead compounds. The concentration of polycyclic aromatic hydrocarbons in the exhaust gas reaches values of 0.3-0.5%. Such values can be suppressed by using a single discharge tube as mentioned in the above-mentioned Certificate of Invention. On the contrary, the carbon monoxide concentration in the exhaust gas varies within the range of 2-6% or more. To eliminate such amounts, approximately 5
It is necessary to use a system consisting of a plurality of identical discharge tubes capable of treating the exhaust gas produced by a total engine volume of 0-. In this case, the presence of air is necessary for dispersing the carbon oxide, which impairs the effectiveness of the device for several reasons and more particularly for the following reasons:
For the basic reaction, decomposition of water vapor is necessary. However, the presence of air reduces the degree of water decomposition and further reduces the co
10) The reaction of l is replaced by the reaction of co"+o-, whose rate is more than 14 orders of magnitude slower than that of CO+OH.

According to Czechoslovak Inventor's Certificate No. 195.115, another arrangement of electrodes is used, namely a grid specifically directed towards the exhaust gas stream, as well as a cylinder identical to the exhaust manifold. Under these conditions there is a half-open discharge of interest here. This is because no axial effects on the exhaust gas occur. Apart from this, the source used would have insufficient power, resulting in pulsed discharges. This discharge is characteristic for the preliminary or initial stage of corona discharge only. In this case, the electron wind does not perform its function; the discharge has no effect on solid and liquid components, - its effect on carbon oxides is hardly considered.

There is no mention of any measurement of the efficiency of the device or the operating mechanism.

In PCT WO84102743 a combined device is disclosed in which a chemical filter (activated carbon) and an electrical filter in the form of a corona discharge are utilized. The device consists of a negatively charged high-voltage electrode, which consists of several grids that are directly electrically coupled to each other so that the potential is the same. Inside the inner electrode space there is activated carbon, which contains solid particles, several gas components (
CO1 hydrocarbons) and especially retain moisture. The grid forms an incomplete cycle. A container is provided in the lower circular recess into which the solid particles or water respectively fall under the vibrations of the vehicle. Such negatively charged electrodes are electrically insulated from the annular collector earth electrode. A partially closed corona discharge burns between the two electrodes.

Electron winds do not appear themselves in the system, but they do exist in parts. As a result of the power of 40-60 W and the presence of a chemical filter upstream of the discharge zone, the discharge burns in a space free of water and solid particles, so that no reaction of CO+OH takes place. - Treatment of carbon oxides is carried out partly by adsorption on carbonated carbon or partly by co”
+o- reaction (this reaction is much slower than the CO+OH reaction).

The concurrently filed USSR Inventors' Certificates No. 977.842 and No. 977.843 each disclose a device of one type and operating on the same principle. The device is based on a positive corona discharge (No. 1843 discloses two types of discharge in different devices), which burns in the exhaust gas and the arrangement of electrical points/surfaces. have The system is positioned axially within the exhaust manifold, which activates the exhaust gas mixture to produce positive Cn8m ions.

In this mixture, fresh air is mixed, but before this mixing the negative corona discharge is burned in the point 7 plane arrangement (0- generation). The two mixtures react with each other plasma-chemically. Due to the presence of air, the reaction co + on does not occur. Although not explicitly mentioned, the reaction CO''''+0- is probably occurring. Point 7
Since the surface system is small and one of the electrodes does not react with the exhaust system wall, no wind of electrons is revealed.

Within the exhaust system, there are devices based on axially arranged corona discharges that are considered the most effective. Such devices operate with separate air and affect polycyclic aromatic hydrocarbons.

The disadvantages of this type of single device are: - the effectiveness of the device against carbon oxides is limited, due to the additional air supply required;

Furthermore, in the case of wider manifolds and therefore larger flows of exhaust gas, a single discharge tube cannot provide sufficient efficiency of the device. Considering the relatively large distance of the internal electrodes, which corresponds to the diameter of the tube used, the voltage required for the discharge increases rapidly. If a longer discharge tube is used, the reverse decomposition of the product occurs, eg from carbon dioxide to carbon monoxide.

[Means for solving the problem, action and effects of the invention]

It is an object of the present invention to overcome the drawbacks of the prior art and to provide a device for continuously reducing the concentration of carbon monoxide and other harmful exhaust types.

In this device, the exhaust air flows through a system comprising a plurality of coaxial corona discharge tubes of the wire/cylinder type, the individual corona discharge tubes extending in parallel and connected to each other in parallel, and each of them Connected to a normal high voltage source through a resistor. The external electrodes of the system are connected to one another by a capacitor.

The advantages of the device according to the invention for continuously reducing the concentration of carbon monoxide and other harmful emissions with parallel and coaxial corona discharge are as follows. Even in the case of large diameter manifolds with relatively high discharge flows, the device has sufficient effectiveness at nearly constant operating pressure. A higher discharge of the device can be achieved by passing a larger current through the discharge tube system, where the current is the sum of the currents in all discharge tubes. By selecting an appropriate number of individual discharge tubes in the system and their diameters, it is possible to provide the device with a particularly constant high pressure of the high pressure source in the exhaust manifold of a wide range of diameters as well as a high discharge flow rate rate. It is. This fact is extremely important from several aspects, such as the implementation of high voltage sources, the safety of the system and the use of suitable electrically insulating materials.

For better understanding and implementation of the present invention, preferred embodiments thereof will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a single corona discharge tube in a system, FIG. 2 is a cross-sectional view of several discharge tubes in a geometrical arrangement, and FIG. 3 is a corona discharge tube system. FIG.

As is clear from the drawings, especially from FIG.
A resistor 5 is connected to the discharge tube and to a high voltage source 6.

FIG. 2 shows a system of 19 parallel array coaxial discharge tubes arranged in a circular configuration, each tube being mounted within a block of electrically insulating material. FIG. 3 shows a similar system of discharge tubes arranged in an oval shape.

The device of the invention is implemented in prototype form and the second
It has been specifically applied to automotive exhaust manifolds in two ways, as described with reference to FIGS. As previously mentioned, each discharge tube is fitted with an electrically insulating material 4, which insulates the two electrodes 1 and 2 from each other, as is clear from FIG. One end is attached by a flange and an auxiliary pipe to the vehicle's exhaust manifold. One of the supporting members 3 of the high-voltage electrode 1 includes a resistor 5 connected to each of the discharge tubes.
It is connected to the high pressure source 6 via. The resistor 5 has a balancing and stabilizing function regarding discharge combustion.

Considering that the length of each discharge tube is 100 mm, the diameter of the outer cylindrical electrode 2 is 10 mm, and the long diameter of the central high voltage electrode 1 is 0.2 mm, the claimed device regarding the high voltage source is as follows. :The operating voltage in the air is about 6kV and the total current is 4.
2+sA. On the other hand, although the values in the emitted mixture vary individually to a considerable extent and depend on the actual composition of the given mixture, the deviations from the values in air as well as motor vehicle exhaust gases are not large. After operating the high pressure source, the corona discharge that begins combustion in the exhaust mixture reduces the concentration of carbon monoxide and other emissions such as steam and soot in the presence of water vapor.

In fact, the device according to the invention is applicable to exhaust manifolds of different diameters, exhaust gas flows and different sources thereof. It is perfectly sufficient to use a single coaxial metal discharge tube of the wire-cylinder type for a compact machine with a cylinder volume of 50 cj, the prototype of which was tested for compact machines and motor vehicle exhaust gases. For automobiles, it is necessary to use approximately one corona discharge tube for each 50 cd cylinder volume of the engine.

If the device is used to treat emissions from factory chimneys, up to 7000 coaxial discharge tubes should be utilized.

The concentration of a few drops of specific components of the exhaust gas was determined by infrared absorption spectroscopy. It was confirmed that the concentration of specific components in both polarities of the discharge decreased within the following ranges: 50% to 100%;
Nitrogen oxides (NOx) 45% to 100%; Hydrocarbons (COX) 90% or more; Lead (two types of compounds) 8
0% or more; oil smoke, smoke, solid and liquid particles 90% or more.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a single corona discharge tube in a system, FIG. 2 is a cross-sectional view of several discharge tubes in a geometrical arrangement, and FIG. 3 is a corona discharge tube system. FIG. ■...High voltage electrode, 2...External electrode, 5...
··Resistor.

Claims (1)

[Claims] 1. A device for continuously reducing the concentration of carbon monoxide and other harmful exhaust gases, comprising a plurality of coaxial corona discharge tubes of the wire/cylinder type, the individual corona discharge tubes having a geometric shape. arranged in an arrangement and further connected in parallel to each other, and each of them is connected to a conventional high voltage source (6) via a resistor (5), and the external electrode (2) is connected to a capacitor. The device, characterized in that: