US3922136A

US3922136A - Catalytic gas converter

Info

Publication number: US3922136A
Application number: US421684A
Authority: US
Inventors: Christian Koch
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1972-12-11
Filing date: 1973-12-04
Publication date: 1975-11-25
Anticipated expiration: 1992-11-25
Also published as: NL7314826A; JPS4987919A; BE808294A; FR2209895A1; DE2260586A1; SE401252B; IT1002208B; CA1003743A; FR2209895B1; DE2260586B2; GB1433010A

Abstract

The invention concerns an arrangement for the complete combustion of a liquid fuel. According to the invention, this arrangement comprises a catalytic gas converter (reformed-gas generator) suitable also for heavy hydrocarbons, a radiation plate system and a mixing arrangement for mixing the fuel gas generated by the converter with secondary air and for directing said mixture through said radiation plate for conversion to thermal energy.

Description

United States Patent Koch 1 Nov. 25, 1975 [54] CATALYTIC GAS CONVERTER 3.l99.505 8/[965 Lloyd 43l/328 3 l99 568 t l/i965 Bztumunns et a]. ,931/3213 [75) mentor: 3228.451 1/1966 Fraser et al 431/10 Numbergfimssgrundlach 3.418.979 12/1968 Reichmunnsm 431/323 Germany 3 21.859 1/1969 Kruggel r. 431/328 4 3.734,677 5/!973 Murase .3 431/329 [73] Absgnee' Akt'engeseuschaf 3,787,|68 1/1974 Koppzmg et al 431/115 Germany 3,832 l22 13/1974 Huye et ill 1. 431/351 [22] Filed: Dec. 4, 1973 I Primary Exum1'nerCarroll B. Dorityg Jr [2]] Appl' 421684 Armrney, Agent. or Firm-Kenyon & Kenyon Reilly (arr & Chapin [30] Foreign Application Priority Data Dec. ll. I972 Germany 2260586 [57] ABSTRACT [52] us. Cl 3 431/115; 431/328 The t arrangeme' the 9" 2 plete combusuon of a llquld fuel According to the 1n- [5l] Int. Cl. F23D 13/12 Vemion this amm emem Com meg a Calal tic I [58] Field ofSearch ..43l/ll5,328 329, 10-, g p y 23/777 C eonverter (reformed-gas generator) su1tt1ble also for heavy hydrocarbons, a radiation plate system and a Rekrences Ched mixmg arrangement for mixing the fuel gas generated by the converter with secondary air and for dlrectmg UNITED STATES PATENTS said mixture through said radiation plate for conven l,732,4l2 lO/l929 Montague ,1 43lfl0 sion to thermal energy. 3,068,8l2 l2/l962 Hemeon 3.173470 3/1965 Wright H 431/328 7 Claims 3 Drawmg Figures US. Patent Nov. 25, 1975 3,922,136

o O Q00 C ATALYTIC G AS CONVERTER BACKGROUND OF THE INVENTION The present invention concerns an arrangement for the complete combustion of a liquid fuel but, particu larly. an arrangement utilizing catalytic gas converters.

The increasing pollution of the air leads to a steadily increasing danger to the health of the population, particularly in densely populated areas. Exhaust gases of motor vehicles with internal-combustion engines and of heat generators contribute to this to a considerable extent. Incomplete combustion results from nonuniform evaporation and mixing of the hydrocarbons with the combustion air. As a consequence, unburned or partially burned hydrocarbons, carbon monoxide, condensed products, benzpyrene, tar, soot and aldehydes are found in the exhaust gas, which are given off to the ambient air, Of grave importance is the simultaneous emission of hydrocarbons and nitrogen oxides, as strongly toxic compounds are formed from these, particularly under the influence of sun light.

These harmful secondary effects due to the exhaust gases of motor vehicles with internal-combustion engines can be reduced very substantially by the use of a so-called catalytic gas converter (reformed-gas generator). In the German Offenlegungsschrift 2,103,008 and the not previously published German Offenlegungsschrift 2,135,650 the principle of such a catalytic gas converter is described. The fuel containing liquid hy drocarbons, such as gasoline, is first evaporated, gasified or atomized and the gaseous or vaporous fuel is conducted over a catalyst disposed on a catalyst carrier for conversion into a gas mixture (so-called reformed gas). This mixture contains essentially carbon monoxide, carbon dioxide, methane and/r hydrogen. To provide a substantially soot-free conversion, the gaseous or vaporous fuel is combined with fed-back exhaust gas of the internal combustion engine and/or other gases serving as oxygen carriers. Prior to its introduction into the combustion chambers of the internal-combustion engine, an oxygen carrier, such as air, is mixed with the reformed gas. The catalyst carrier can advantageously be in the form of highly porous sintered blocks with a large number of passage openings for the gas, which are arranged approximately parallel to each other.

It is now an object of the invention to describe also for heat generators an arrangement which makes possible complete combustion of the liquid fuel fed to them, with negligible emission of harmful substances.

SUMMARY OF THE INVENTION For solving this problem, it is proposed that the arrangement comprise a catalytic gas converter suitable also for heavy hydrocarbons, a radiation plate system and a mixing arrangement for mixing the fuel gas (reformed gas) generated by the catalytic converter with secondary air.

The catalytic gas converter is preferably designed so that the reformed gas generated in it has overpressure.

The mixing arrangement in one embodiment comprises mixing nozzles which are arranged between the catalytic converter and the radiation plate system advantageously in the form of a ring. In another embodiment the mixing arrangement comprises a mixing chamber arranged between the catalytic converter and the radiation plate system.

2 The catalytic gas converter is preferably connected with the radiation plate system in such a manner that part of the exhaust gases is fed to it periodically or continuously.

The invention will be explained in detail in the following specification with reference to the figures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1, a schematic overall view of one arrangement according to the invention;

FIG. 2, a plan view of the radiation plate system; and,

FIG. 3, a cross section elevation view of another embodiment of the arrangement.

DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 is a schematic representation of an embodiment of this invention. Catalytic gas converting cham ber 10 includes a fuel mixing chamber 12 which is positioned above and axially aligned with blower 13. Fuel is introduced into the fuel mixing chamber 12 via fuel feed line 14. An ignition device 16, is also suitably posi' tioned in the fuel mixing chamber 12.

Axially displaced from the blower l3, and bounding the opposite end of the fuel mixing chamber 12, is a fuel distributor or carburetor 18. The carburetor 18 includes a multiplicity of parallel openings 19 which tend to insure uniform distribution of the fuel as it proceeds axially along the length of the converting chamber 10.

At the one end of the converting chamber 10 there is located the catalytic gas converter comprising one or several catalytic or non-catalytic perforated sintered blocks 22. These include a plurality of openings 24 which have their axes essentially parallel to each other and to the centerline of the chamber 10.

Positioned at the end 25 of the catalytic gas converting chamber 10, is a mixing chamber 26. This includes a cylindrical shaped portion 28 and a truncated conical section 30 interposed between the cylindrically shaped portion 28 and the gas converting chamber 10. On the side walls 32 of the truncated section 30, there is located a plurality of intake orifices 34. These orifices 34 are connected to an oxygen bearing gas supply which generally would be the air.

Interior to the mixing chamber 26 and axially displaced from end 25 of the gas converting chamber is a truncated conical ring plate 36. This ring plate 36 includes a plurality of mixing nozzles 38, the center line of which preferably is coaxially aligned substantially, with the center line of intake orifices 34.

Secured in a continuous fashion with the sidewalls of the cylindrical shaped portion 28 is a radiation plate 40. A plan view of radiation plate 40 is shown in FIG. 2. The plate 40 may be constructed from either a low thermal conductivity, highly porous, non-catalytic ma terial or, alternately, it may be constructed from a high thermal conductivity material with a finely-distributed, suitable catalyst disposed in the porous material. The plate 40 includes a plurality of essentially parallel open ings 42 which communicate between the mixing chamber 26 and the exhaust side 43, of plate 40.

In a preferable variation of this embodiment there is inserted into the sidewall of cylindrical portion 28 on the exhaust side of plate 40, an exhaust gas feed line 44, which is connected therefrom back to the mixing chamber 12 via blower 13 through a valve arrangement 46. This arrangement permits intermittent or continuous feedback of the exhaust gases to thereby provide an additional burning of the exhaust gases resulting in a 3 still further reduction of pollutants.

The operation of the configuration of FIG. I would be as follows. A suitable fuel containing liquid hydrocarbons, such as gasoline, is supplied to the fuel mixing chamber 12 via fuel feed line 14. Blower l3 forces air into the mixing chamber and the resultant mixture of air and fuel through the fuel distributor l8 and then across the catalytic, perforated sintered blocks 22. Pas sage of the fuel-air mixture as it comes from the fuel distributor I8 over the appropriately selected catalytic sintered blocks 22 produces a gas (so-called reformed gas) which contains essentially carbon monoxide, car bon dioxide, methane and/or hydrogen.

The reformed gas exits end 25 and enters the mixing chamber 26 at a velocity which is determined by the blower rate and diameter of

openings

19 and 24. Because of the forcing of the fuel-air mixture and then the reformed gas through the gas converting chamber by blower 13, a pressure differential is created between the interior of the mixing chamber 26 and the exterior thereof which results in the oxygen bearing gas being sucked in through intake orifices 34 and mixed with the reformed gas by way of nozzles 38. The design of the system is such that the pressure of the gas-air mixture as it exits from the nozzles 38 is suitable to overcome the subsequent flow resistance of the radiation plate.

The combined reformed gas-air mixture is next forced through the radiation plate 40. When the radiation plate 40 is constructed from the high thermally conductive, catalytic material, the reaction of the reformed gas and air as assisted by the material causes substantially higher temperatures than when the plate is made from the low thermally conductive, noncatalytic material. The exhaust gases which exit from the radiating side of plate 40, although generally low in recognized pollutant content can be fed back to the mixing chamber 12 via the optional exhaust feedback line 44. Upon suitable actuation of valve 46 exhaust gases can be drawn back through the line 44 and sucked into the mixing chamber in much the same fashion as the air was drawn into the mixing chamber as described above. Valve 46 can be adapted such that it continuously feeds back the exhaust gases or only periodically.

FIG. 3 describes an alternate embodiment within the scope of the present invention. The catalytic gas converting chamber 10 contains essentially the same elements as its corresponding number in FIG. I, such member being identified with like numerals. I-Iere, however, instead of the air to be mixed with the reformed gas being introduced through orifices such as 34 in FIG. 1, the air is provided directly by blower 13.

The chamber 10 is surrounded by an outer shell 50. The shell includes a portion 52 which is contoured to the shape of chamber 10 and a truncated cone section 54. A passageway 55 is formed between the chamber and the outer shell. This connects the blower l3 directly to a mixing chamber 56 formed by the truncated cone section 54.

Integral with the sidewalls of the truncated cone section 54 is a mixing vane plate 57 which forms an opening coaxial with the center line of chamber 10 through which the gas exiting from the gas converting chamber 10 must pass.

Positioned at the truncated end 58 of the shell 50 is a radiation plate system 59 which communicates therewith. It generally has an inverted truncated cone shape as depicted. Positioned axially away from end 58 is the radiation plate 60. Like its counterpart in FIG. 1 this 4 radiation plate is constructed of either a low thermal conductivity, highly porous material without catalyst or a high thermally conductive material including a finely distributed catalyst disposed therein. It further includes a plurality of openings 62 necessary to maintain the proper gas flow through the device.

As with the embodiment of FIG. 1, the sidewall to which the radiation plate is affixed may be extended a distance beyond the exhaust side 63 of the radiation plate. Exhaust gas feed line 64 may be positioned therethrough. Upon actuation of the control valve 66 the exhaust gases emanating from the radiation plate may be fed back through the valve into the mixing chamber I2, preferably via blower 13. The operation of this device is as follows. The oxygen bearing gas or air drawn in from outside the device by the blower I3 is divided into two gas streams. One of the gas streams is led to the fuel distributor 18, the other one which is provided for mixture with the reformed gas passes through the pas sageway S5. The mixing vanes direct this second gas stream into the exhaust area from the gas converter 10, in which the vaporized fuel and the first gas stream are reacted to form the reformed gas. The restricting orifice formed by the vanes forces the mixture of the air with this reformed gas, The air-gas mixture is thrust into the radiation plate system 59 at a pressure suitable to overcome the subsequent flow resistance of the radiation plate. It thereafter dissiminates through the porous material of the plate 60 causing a high speed reaction at high temperatures which results in intensive radiation heat and the conversion of the gas-air mixture to a low pollutant form.

Additional refinement of the exhaust gas can be provided through the feedback of the exhaust gas, either on an intermittent or continuous basis through exhaust feed lines 64 and control valve 66.

The conversion of the liquid fuels into gases and the thorough mixing of these gases with air prior to the combustion by the arrangement according to the invention thus make possible complete combustion with negligible emission of harmful substances. The heat transfer conditions and the efficiency are improved by the high combustion temperatures. By using a flameless burner, the heat transfer conditions are improved still further over the flame because of the higher radiation coefficient of the radiation plates.

Other variations of the scheme above will be evident to those skilled in the art and the descriptions herein are not intended to restrict the scope of the claims as hereinafter appended.

What is claimed is:

I. An apparatus for the complete combustion of a liq uid fuel which comprises:

a, means for converting said liquid fuel to a reformed gas containing carbon monoxide, carbon dioxide, and at least one of the group consisting of methane and hydrogen;

b. means for producing a mixture of said reformed gas and oxygen bearing gas; and

c. a radiation plate having a plurality of essentially parallel openings therethrough, one side of said openings being coupled to said means for producing a mixture so as to conduct said mixture from said means for producing through said parallel openings to the other side of said radiation plate said radiation plate adapted to react with said mixture as it passes through openings to produce substantially complete combustion of said liquid fuel.

2. The apparatus of claim 1 wherein said means for producing a mixture of said reformed gas and said oxygen bearing gas include:

a. a first mixing chamber located between said converting means and said radiation plate means;

b. means for blowing said liquid fuel through said converting means such that said reformed gas exits from said converting means into said first mixing chamber at a predetermined velocity;

c. means for directing said oxygen bearing gas into the path of said exiting reformed gas to provide a prescribed mixture of both.

3. The apparatus of claim 2 where said means for converting said liquid fuel to said reformed gas is adapted to convert liquid fuel composed of heavy hydrocarbons.

4. An apparatus for the complete combustion of a liquid fuel which comprises:

a. means for converting the liquid fuel to a reformed gas;

b. a first mixing chamber coupled to the outlet of said means for converting;

c. means for blowing said liquid fuel through said converting means such that said reformed gas exits from said converting means into the said first mix ing chamber at a predetermined velocity;

d. a plurality of orifices communicating between an oxygen bearing gas and said first mixing chamber;

e. a ring plate having a plurality of mixing nozzles positioned thereon said nozzles bearing a predetermined relationship to said orifices and the exhaust orifice of said converting means to thereby mix said oxygen bearing gas with said reformed gas in a prescribed mixture of both;

. a radiation plate containing a plurality of essentially parallel openings having inputs coupled to the output of said first mixing chamber and adapted to react with said mixture to produce substantially completed combustion of said liquid fuel as said mixture passes through said openings. 5. The apparatus of claim 4 further including means for feeding back the exhaust gases produced by said ra- 5 diation plate means to a second mixing chamber located between said blower means and said converting means to be mixed therein with fuel and oxygen bearing gas.

6. An apparatus for the complete combustion of a liquid fuel which comprises:

a. means for converting the liquid fuel to a reformed b. a first mixing chamber coupled to the outlet of said means for converting;

c. means for blowing said liquid fuel through said converting means such that said reformed gas exits from said converting means into said first mixing chamber at a predetermined velocity;

d. passageway means communicating between said blower means and said first mixing chamber, said blower means forcing an oxygen bearing gas into said passageway; and

e. mixing vane means secured to the walls of said first mixing chamber and adapted to direct the oxygen bearing gas exiting from said passageway into the path of said exiting reformed gas;

f. a radiation plate containing a plurality of essentially parallel openings having inputs coupled to the output of said first mixing chamber and adapted to react with said mixture to produce substantially complete combustion of said liquid fuel as said mixture passes through said openings.

7. The apparatus of claim 6 further including means for feeding back the exhaust gases produced by said radiation plate means to a second mixing chamber located between said blower means and said converting means to be mixed therein with fuel and oxygen bearing gas.

* t i t t

Claims

1. AN APPARATUS FOR THE COMPLETE COMBUSTION OF A LIQUID FUEL WHICH COMPRISES: A. MEANS FOR CONVERTING SAID LIQUID FUEL TO A REFORMED GAS CONTAINING CARRBON MONOXIDE, CARBON DIOXIDE, AND AT LEAST ONE OF THE GROUP CONSISTING OF METHANE AND HYDROGEN, B. MEANS FOR PRODUCING A MIXTURE OF SAID REFORMED GAS AND OXYGEN BEARING GAS; AND C. A RADIATION PLATEHAVING A PLURALITY OF ESSENTIALLY PARALLEL OPENINGS THERETHROUGH, ONE SIDE OF SAID OPENINGS BEING COUPLED TO SAID MEANS FOR PRODUCING A MIXTURE SO AS TO CONDUCT SAID MIXTURE FROM SAID MEANS FOR PRODUCING THROUGH SAID PARALLEL OPENINGS TO THE OTHER SIDE OF SAID RADIATION PLATE SAID RADIATION PLATE ADAPTED TO REACT WITH SAID MIXTURE AS IT PASSES THROUGH OPENINGS TO PRODUCE SUBSTANTIALLY COMPLETE COMBUSTION OF SAID LIQUID FUEL.

2. The apparatus of claim 1 wherein said means for producing a mixture of said reformed gas and said oxygen bearing gas include: a. a first mixing chamber located between said converting means and said radiation plate means; b. means for blowing said liquid fuel through said converting means such that said reformed gas exits from said converting means into said first mixing chamber at a predetermined velocity; c. means for directing said oxygen bearing gas into the path of said exiting reformed gas to provide a prescribed mixture of both.

4. An apparatus for the complete combustion of a liquid fuel which comprises: a. means for converting the liquid fuel to a reformed gas; b. a first mixing chamber coupled to the outlet of said means for converting; c. means for blowing said liquid fuel through said converting meanS such that said reformed gas exits from said converting means into the said first mixing chamber at a predetermined velocity; d. a plurality of orifices communicating between an oxygen bearing gas and said first mixing chamber; e. a ring plate having a plurality of mixing nozzles positioned thereon said nozzles bearing a predetermined relationship to said orifices and the exhaust orifice of said converting means to thereby mix said oxygen bearing gas with said reformed gas in a prescribed mixture of both; f. a radiation plate containing a plurality of essentially parallel openings having inputs coupled to the output of said first mixing chamber and adapted to react with said mixture to produce substantially completed combustion of said liquid fuel as said mixture passes through said openings.

5. The apparatus of claim 4 further including means for feeding back the exhaust gases produced by said radiation plate means to a second mixing chamber located between said blower means and said converting means to be mixed therein with fuel and oxygen bearing gas.

6. An apparatus for the complete combustion of a liquid fuel which comprises: a. means for converting the liquid fuel to a reformed gas; b. a first mixing chamber coupled to the outlet of said means for converting; c. means for blowing said liquid fuel through said converting means such that said reformed gas exits from said converting means into said first mixing chamber at a predetermined velocity; d. passageway means communicating between said blower means and said first mixing chamber, said blower means forcing an oxygen bearing gas into said passageway; and e. mixing vane means secured to the walls of said first mixing chamber and adapted to direct the oxygen bearing gas exiting from said passageway into the path of said exiting reformed gas; f. a radiation plate containing a plurality of essentially parallel openings having inputs coupled to the output of said first mixing chamber and adapted to react with said mixture to produce substantially complete combustion of said liquid fuel as said mixture passes through said openings.