CN1011292B - Apparatus for puritying exhaust gas - Google Patents

Abstract

The device of the present invention is composed of a casing 1, a combustion chamber 2 arranged in the casing 1 and a combustion nozzle 3, wherein a connecting pipe 4 is arranged above the combustion chamber 2; a secondary combustion chamber 5 and a heat exchanger 11 are orderly arranged behind the combustion chamber 2; catalytic elements 6 and 7 are arranged in the secondary combustion chamber 5; the catalytic elements 6 and 7 are two quadrangular bodies aslant arranged whose top edges are in contact with each other. A V-shaped distributive grid 16 is arranged between the heat exchanger 11 and the secondary combustion chamber 5; the top of the grid is toward one surface of the secondary combustion chamber 5. The installation of the connecting pipe 4 needs to meet the condition that the axial line 8 of the connecting pipe 4 can be crossed with the axial line 9 of the combustion nozzle 3.

Description

Apparatus for puritying exhaust gas

The invention belongs to the industrial waste burner, promptly eliminate the device of waste gas or pernicious gas specifically, just purify the device of exhausting system combustion gas.

Can use device of the present invention effectively, be to need aborning with an organic solvent and the paint workshop section and the dry workshop section of local exhaust equipment is housed in the operational area and accomplishes to discharge the purifier of low concentration gas.

The present invention is applicable to machinery, metallurgy, instrument manufacturing and other any industrial departments that the paint work post is arranged.

Known a kind of waste gas purification apparatus (SU, A520489), be combustion chamber, the mixing chamber of being with antipriming pipe that the band burner is housed in housing successively, the secondary combustion chamber of being with the catalysis element of forming by two coaxial cones of porous, and tubular heat exchange.

The effect of mixing chamber antipriming pipe is to reach even heating to make combustion gas that the temperature that oxidation reaction takes place can be arranged when catalysis element.Because burner position and mixing chamber antipriming pipe can not guarantee that burning gases evenly mix with combustion gas on same axis, therefore the temperature field of air-flow is inhomogeneous before catalysis element, the inefficiency of device.In addition, the shape owing to catalysis element being made two coaxial cones of porous in order to make the very big secondary combustion chamber of volume heat insulation, needs extra-pay.

A kind of waste gas purification apparatus of West Germany (LURGI " by bleeding and catalytic purification waste gas ") also is the combustion chamber that a band burner is arranged in housing, is adorning the tube connector of introducing combustion gas on it.Be secondary combustion chamber and heat exchanger successively after the combustion chamber.Catalysis element arranged in that second-time burning is indoor.Catalysis element is a horizontal positioned.The tube connector of introducing combustion gas is parallel with burner mutually.

The combustion chamber of this catalysis element horizontal positioned and second-time burning cell structure to catalysis element before air velocity evenly caused adverse effect, therefore cause that the load of catalysis element individual areas is inhomogeneous, worsen with the work that causes device.Introduce the parallel non-uniform temperature that can make the preceding air-flow of catalysis element equally of tube connector of waste gas, therefore also just worsened the working condition of device with burner.

Basic task of the present invention is a kind of combustion chamber and second-time burning cell structure of having improved of development, can guarantee the heat exchanger inlets air-flow purifier of combustion gas equably.

Essence of the present invention is that the combustion chamber of a band burner is arranged in the apparatus for puritying exhaust gas housing, have introducing to want the tube connector of combustion gas above burner, is secondary combustion chamber and the heat exchanger that catalysis element is installed successively after the combustion chamber.According to invention, between heat exchanger and secondary combustion chamber, there is a V-arrangement to distribute grid, its top is towards the secondary combustion chamber one side.In addition, catalysis element is made two tilted-putted four bank or ridge forms, and their top seamed edge contacts with each other.The installation site of tube connector can guarantee its axis and burner axes intersect, and is even with the temperature of guaranteeing air-flow.

Preferably 120～140 ° of the drift angles of distribution grid.

The intersection point of suggestion tube connector axis and burner axis is on the chamber wall on burner opposite.

The appropriate design on distribution grid surface is, the cross section, hole accounts for 20～40% of the grid gross area, and the flow deflector of turning back is downwards arranged, and the grid top is protruding towards the one side of flow deflector.

Owing to distribution grid is arranged, can guarantee that the air-flow of heat exchanger inlets evenly distributes under the condition apart from the weak point of trying one's best at secondary combustion chamber and heat exchanger.Catalysis element is made the tilting four bank or ridge form that can contact each other at its top seamed edge; uniformity in the time of can guaranteeing waste gas by catalysis element and when the exceedingly odious duty of burner and do not have under the condition of additional protection measure the influence that the protection catalysis element is not sprayed by flame again.

In order to further specify the present invention, will illustrate its structure below for example and the profilograph of the waste gas purification apparatus drawn according to the present invention.

This device is made up of housing 1 and combustion chamber wherein 2 and burner 3.The tube connector 4 of introducing waste gas is arranged above burner 3.Above the combustion chamber 2 secondary combustion chamber 5 and two catalysis elements 6 and 7.Tube connector 4 and burner 3 are contained on the same wall of combustion chamber 2.The axis 8 of tube connector 4 intersects at a little 10 with the axis 9 of burner 3 on 2 opposite walls of combustion chamber.Tube connector 4 axis 8 and burner 3 axis 9 intersect at the reasonability of this point, can be proved by following formula:

${\mathrm{△\; t}}_X\mathrm{=\; △\; to\; ·\; n}\sqrt{\frac{\mathrm{bo}}{x}}$

△ tx-waste gas stream and burning gases stream are temperature difference on the x in distance in the formula;

The x-EGT falls maximum place to temperature and falls distance between the minimum place;

△ t ₀-in the temperature difference of burner 3 exit waste gas streams with burning gases;

The temperature varying coefficient of n-waste gas in burning gases stream;

b ₀The tube connector 4 of-introducing waste gas is at the height in exit.

Can find out by following formula, fall △ tx minimum thereby make, then the tube connector 4 of introducing waste gas must be arranged in and make its axis 8 and burner 3 axis 9 intersect at position on 2 walls of combustion chamber, burner 3 opposite apart from the maximum temperature of waste gas stream when entering catalysis element that has heated that make of x.

Installation has the heat exchanger 11 of three conduits 12,15,14 on secondary combustion chamber 5.Conduit 15 communicates with arm 13, so that part waste gas is sent into burner 3.Between heat exchanger 11 and secondary combustion chamber 5, the V-arrangement distribution grid 16 that makes the air-flow homogenising is housed.Because distribution grid is located immediately between heat exchanger 11 and the catalysis element 6,7, thereby can guarantee that heat exchanger 11 inlet air flow velocity uniformities reduce the volume of purifier, and also just reduced the heat loss that enters in the environment owing to reduced the heat release area.Distribution grid 16 has a top facing to secondary combustion chamber 5.The drift angle of distribution grid 16 is 120～140 °.

Outside this scope, the air-flow nonuniformity coefficient that is calculated by following formula can sharply increase as drift angle:

$\mathrm{K\; =}\frac{V_{\mathrm{m\; a\; x}}}{V_{\mathrm{m\; i\; n}}}$

K-air-flow nonuniformity coefficient in the formula,

V _Max-air-flow maximal rate,

V _Min-air-flow minimum speed.

When drift angle was 120～140 °, the air velocity nonuniformity coefficient was not more than 10%, and fluid pressure loss is 10～15 crust.

There are a plurality of holes on distribution grid 16 surfaces, and the cross section, hole accounts for 20～40% of distribution grid 16 gross areas.If the cross section, hole is less than 20% of distribution grid 16 gross areas, then the heat loss on the grid sharply increases.If the cross section, hole is greater than 40% of distribution grid 16 gross areas, then the air velocity unevenness sharply increase-can reach 25% unevenness even higher.Each Kong Youyi on distribution grid 16 surfaces is the flow deflector 17 of bending downwards, and these flow deflectors are convex shape in the one side towards distribution grid 16 tops.Flow deflector 17 is necessary in order to change airflow direction before heat exchanger 11 imports.The catalysis element 6,7 of secondary combustion chamber 5 is made two four bank or ridge shapes tilting, that contact with each other at the top seamed edge.Arranged catalysis element at 6,7 o'clock like this, the space that enters 6,7 of catalysis elements owing to the heat exhaust gases from combustion chamber 2 evenly dwindles by Zhejiang, and it is even that air velocity becomes.6,7 spaces of catalysis element are evenly reduced by base to top margin, and therefore heat exhaust gases stream from the bottom to top also evenly reduces, and all pass through the filtering surface of catalysis element 6,7 down to whole throughputs near top contact seamed edge the time.Because dwindling with gas flow by Zhejiang, the space of 6,7 compositions of catalysis element reduces pro rata therewith, so the air velocity on the whole filtering surface of catalysis element equates that this also is for obtaining the uniform condition of air velocity.

The course of work of this device is as follows:

Combustion gas enters heat exchanger 11 through blast pipe 12, the quilt heat heating of Purge gas in heat exchanger.Part waste gas enters combustion chamber 2 through conduit 15 and tube connector 4.Another part waste gas enters burner 3 via arm 13, in order to guarantee to introduce the combustion process of gas combustion such as the coal gas in the gas tank.After this, the burning gases by burner 3 ejections mix with combustion gas in burner 3 axis 9 directions.Flow and mix along the direction of tube connector 4 axis 8 by the waste gas of tube connector 4 with burning gases.For burning gases can effectively be mixed with combustion gas, tube connector 4 and burner 3 must guarantee structurally that the axis 8 of tube connector 4 is crossing with point 10 places of axis 9 on 2 walls of the combustion chamber on burner 3 opposites of burner 3.Waste gas is heated to uniform temperature in mixed process after, promptly enter secondary combustion chamber 5,, and carry out the nonflame oxidation, purification process of combustion gas thereon by the air inlet face of catalysis element 6,7.Then, purified waste gas is passed through distribution grid 16.The flow deflector 17 of distribution grid 16 can guarantee that air-flow is further even.Purified waste gas is conducted the part heat the new combustion gas that enters to by blast pipe 12 there again through over-heat-exchanger 11, and purified waste gas is drawn out to the device outside through top blast pipe 14 then.

Adopt above-mentioned purifier can improve the operating efficiency of device, reduce its contour dimension and metal use amount.

Claims (3)

1, apparatus for puritying exhaust gas comprises housing (1) and is positioned at wherein combustion chamber (2) and burner (3), the tube connector (4) of introducing combustion gas is housed in the top of burner (3), the back of (2) in the combustion chamber, be that catalysis element (6 is equipped with in the inside successively, 7) secondary combustion chamber (5) and heat exchanger (11), it is characterized in that between heat exchanger (11) and secondary combustion chamber (5), a V-arrangement distribution grid (16) being arranged, porose along distribution grid (16) surface, the sectional area in hole equals 20%～40% of the distribution grid gross area, there is the flow deflector (17) of downward bending in each hole, and the top of distribution grid (16) is towards secondary combustion chamber (5) one side projection; Catalysis element (6,7) is made two tilting four bank or ridge that contact with each other at the top seamed edge; The installation site of tube connector (4) can guarantee that its axis (8) and the axis (9) of burner (3) intersect, to reach the gas flow temperature homogenising.

2, by the device of claim 1, it is characterized in that distribution grid (16) drift angle is 120～140 °.

By the device of claim 1, it is characterized in that 3, the axis (8) of tube connector (4) and the intersection point (10) of burner (3) axis (9) are on the wall of burner (3) combustion chamber, opposite (2).