LU86701A1 - PROCESS FOR THE INJECTION BY PNEUMATIC ROUTE OF QUANTITIES OF POWDERED MATERIALS INTO AN ENCLOSURE UNDER VARIABLE PRESSURE - Google Patents

Description

"BL-3980 / BM

Q Λ * 7 Λ a GRAND-DUCHY OF LUXEMBOURG

* Patent N ° O U / V I *

Minister of December 04, 1986 ..... of the Economy and the Middle Classes Tîtrp issued. ïÊÈsm Intellectual Property Service

î re e ivre LUXEMBOURG

Invention Patent Application -------------------------------------------- ----- --------------------------------------------- ------------------------- (1) I. Request

The. Company ditemUL KHRI * LS-A ^^ J2 ^ xim ^ ù! Alsace ^ l22 ^ Lux & afOur & ^ ___ (2) represented..by £ .Meÿers ^ Æ ^ TJE, reglinger ^ .- lng ^ conseilsen..propr. ind ^ ~ (3) 4 £ ruedu.-Cimetière, -Luxembourg., .— act in ..... quality -of. agents _-______ deposit) this -guatre-December mil-neuf — ceat eighty six_______________ (4) at .15 ----------__ hours, at the Ministry of Economy and Middle Classes, in Luxembourg : 1. the present request for obtaining a patent of invention concerning:

Injection process by channel.pnem> atiquef.jde ..... Amount of Aose (5) pulverulent matter, ... in.June ... pregnant ^ findingJ under variable pressure.._______________________________________________________________________________________ 2. description in language - .. .... French ............................................. .of the invention in triplicate; 3. one _______________________________________________ drawing boards, in triplicate; 4. the receipt of the taxes paid to the Luxembourg Registration Office on December 4. 1985_______________; 5. the delegation of power, dated ------------ Luxembourg -----------------------—. the fOfffr -; 6. the successor document (authorization); declares (s) assuming responsibility for this declaration, that the inventor (s) is (are): (6) claims (s) for the above patent application the priority of one (s) application (s) from (7) .............................................. .................................................. ............................... filed in (8) _________________________________________________________________ on (9) ...... ............. ZI .................................... .................--------------------------------- ---------------------------------------------------------- -—...................................

under N ° (10) II .......................................... .................................................. .................................................. .................................................. .............................................

in the name of (11) ........ He ................................... .................................................. .................................................. .................................................. .__................ ..

elect (elect) domicile for him / her and, if designated, for his / her representative, in Luxembourg________________________________ 46 ..... rue du Cimetière, ........... Luxembourg .------ ---------------------------------------------------------- ---------------------_______________ (12) requests (s) the grant of a patent for the invention for the subject described and represented in the abovementioned annexes, with postponement of this issue to .......... eighteen ______________________________________________ · ______________ months. (13)

The / mandate: E ^ estÆevers _________________________________________________________ (14) / T j Π. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of the Economy and the Middle Classes, Intellectual Property Service "in-Lyxembourg, dated: December 4, 1986 / ........-> \ /.? v £ \ Pr. the Minister of Economy and Movennes Classes,. coo /? f V-, ï Ol. \ à ........ êP ........ ........... hours DD · ψ ... rpd

'1 y \ ÿ bSj The head of the intellectual property department, A6SU07_ _'! . EXPLANATIONS RELATING TO FORMLTAÎfc & iÂRéfôÎ.

(if applicable "Request for certificate of addition to the main patent, at the request of main brevei No ............ of ............ (2) enter the last name, first name, profession.

address of the applicant, when the latter is an individual or corporate names, legal form, address of the registered office, when the applicant is a legal person - (3 i enter the "nnw nrvtiAni adnaceo du mondafaîr * aoréé <" n nmnrinté infîircTrfeTli »Muni H'tin TVMivrtir crw / dal e * î1 v 9 ti» it · nr * rrr4 <AHti nar 9 <nC (9nt nnaliti / f ^ manriaiatn ** · / Λ

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BL-3980 / BM

Descriptive memorandum filed in support of an invention patent application for

PAUL WURTH S.A. process for the pneumatic injection of metered quantities of pulverulent materials into an enclosure under variable pressure.

32 rue d'Alsace 1122 Luxembourg% i

Method of pneumatically injecting metered quantities of pulverulent materials into an enclosure which is under variable pressure

The present invention relates to a pneumatic injection method, of metered quantities of pulverulent materials, at different places in an enclosure under variable pressure, according to which a pneumatic mixture is formed in a single metering device. comprising a relatively high content of pulverulent matter in propellant gas, this mixture is propelled through a common primary pipe to a dispensing head in which the mixture is split into secondary streams which are sent respectively to each of the points of injection through secondary lines.

Although not limited thereto, the invention will be described more particularly with reference to its preferred application, that is to say the injection of solid fuels, in particular powdered coal, into an industrial oven, such as a blast furnace.

Among the known methods and installations for injecting solid fuels into a shaft furnace, there are essentially two different types. The former operates with relatively "diluted" air streams, while in the latter, the air streams have a relatively high concentration of powdered coal.

In installations of the first diluted current type, the powdered coal is released under pressure from a distribution hopper in a series of metering units in which the mixture of powdered coal and propellant gas is formed and from which the mixture thus formed is conveyed to the injection points in the shaft furnace. In these installations, a metering device is generally used for each nozzle or for each pair of nozzles, so that the quantities injected through the nozzles can be metered individually.

f 2

The metering devices used are of a type known per se, for example metering units with cellular rotors or metering units with slots as proposed in European patent application No. 0 126 91 7. These installations have the drawback that they require numerous pipes. relatively long between the distribution hopper and the shaft furnace. In addition, dosing can be made difficult by the various variable parameters, in particular the pressure fluctuations inside the oven.

In the second type of installation which uses pneumatic currents with high concentration, only one metering device is used at or downstream of the distribution hopper. In this metering device, the total flow of powdered coal is adjusted so as to inject a predetermined quantity of powdered carbon per unit of time. These installations implement the method described in the preamble, that is to say that the metered stream containing the necessary quantity of coal is divided in a distribution head into secondary streams identical to each other. These installations have the advantage that the dispensing head is placed in the immediate vicinity of the furnace so as to reduce the length of the secondary pipes and therefore the space requirement around the furnace. In these installations, a throttling section is also provided either in the secondary pipes or in the distribution head, where a pressure drop is created which is necessary for acceleration to the sonic speed of the pneumatic current. The acceleration of the pneumatic current to a sonic speed has the advantage that the flow conditions upstream from the place where the supercritical speed occurs are no longer influenced by flow conditions downstream from this place. This has, of course, the great advantage that one no longer has to take into account pressure fluctuations and other variable parameters existing in the enclosure into which the pulverulent materials are injected. Compared to the first type of installation, 3 Λ tion installations operating with concentrated current of the kind described above have the drawback that there is no longer any possibility of individual adjustment of the flow rate for each nozzle.

The object of the present invention is to provide a new method of the type described in the preamble which combines the advantages of the two known methods.

To achieve this objective, the invention proposes an injection process of the kind described in the preamble which is essentially characterized in that the flow rate of the pneumatic current is adjusted in each of the secondary pipes.

This adjustment is preferably made at a section with variable throttling, in which the current is also accelerated to supercritical speed.

The adjustment can be carried out manually or automatically under the control of flow detectors provided in each of the secondary pipes.

A preferred embodiment will be described below, by way of example, with reference to the single figure which represents, very schematically, a pneumatic injection circuit of combustible materials in a shaft furnace. In a primary line 1 0 is formed using a metering device 12 which may be a metering device of the movable slot type, or a hopper with pneumatic metering or other, the pneumatic mixture consisting of powdered coal and gas propulsion and whose flow rate meets the demand for the quantity of coal per unit time from the shaft furnace. In this metering device 12, a pneumatic mixture with a high carbon concentration is formed which can, if necessary, be diluted by the addition of a variable quantity of inert gas injected through a line 14 upstream of the distributor. This pneumatic mixture is sent to a distribution head 16 of the type recommended by Luxembourg patent No 86.034. In this distribution head 16, the primary pneumatic stream is divided into 4 “secondary streams which are sent respectively through secondary conduits to each of the nozzles 22 of a blast furnace not shown. The number of secondary pipes 1 8 can for example correspond to the number of nozzles or half the number of nozzles.

In accordance with the present invention, there is provided in each of the secondary conduits 18 a constriction 20 of variable section. This constriction is preferably carried out with a valve of the type recommended by the Luxembourg patent application No. 86.311, that is to say a valve whose passage is defined by the rotation of a movable sleeve inside a fixed socket, the two sockets being provided with openings and slots which can more or less overlap to define a more or less large passage. The acceleration of the secondary pneumatic currents is preferably carried out at the throttles 20.

The method according to the present invention therefore has all the advantages of the sonic speed injection system, that is to say that the secondary pipes can be as short as possible, so as to reduce the space requirement around the oven. In addition, the metering conditions at the level of the metering device 12 are no longer affected by pressure fluctuations downstream of the throttles 20, in particular pressure fluctuations in the shaft furnace.

The valves 20 can be adjusted manually, to take account of the operation of the oven. The flows passing through the various secondary conduits 18 are therefore established as a function of the openings at the throttles 20, while the total quantity of coal injected per unit of time is determined by the metering device 12.

The function of the distributor 16 is therefore different from that of the distributor proposed by the Luxembourg patent application No 86.034. While in this one the distributor had of course a distribution function, but also a uniform distribution, "* Λ 5 that is to say a distribution such that in each of the secondary pipes circulates the same flow of coal. On the other hand, in the method according to the present invention, the distributor 16 simply serves to divide the primary current into secondary currents whose flow rates are variable as a function of the variable sections of the throttles 20.

It is also possible to measure the flow rate of coal in each of the secondary pipes 18 and to automatically adjust the passage section of the valves 20 so as to have a determined injection flow rate at each of the nozzles 22. This automatic adjustment allows the compensation or elimination of disturbing factors, such as partial obstructions of the secondary pipes 18 or passages in the distributor 16.

Claims (5)

6 "* 1. A process for the pneumatic injection of metered quantities of pulverulent materials at different places in an enclosure under variable pressure, according to which a pneumatic mixture comprising a relatively high content is formed in a single metering device high of pulverulent matter in propellant gas, this mixture is propelled through a common primary pipe to a distribution head in which the mixture is split into secondary streams which are sent respectively to each of the injection points through secondary lines, characterized in that the pneumatic current flow rate in each of the secondary lines is adjusted. 2. Method according to claim 1, characterized in that the adjustment is carried out at a section with variable throttling of each of the pipes. 3. Method according to claim 2, charac terized in that one causes at the level of the sections with variable throttling pressure drops necessary for an acceleration of the current to the speed of sound. 4. Method according to any one of claims 1 to 3, characterized in that the adjustment is carried out manually. 5. Method according to any one of claims 1 to 3, characterized in that the adjustment is carried out automatically under the control of flow detectors provided in each of the secondary pipes.