FR2543132A1 - METHOD AND INSTALLATION FOR MANUFACTURING HYDRAULIC BINDERS - Google Patents

Abstract

THE INVENTION RELATES TO THE MANUFACTURE OF HYDRAULIC BINDERS, WHERE A RAW MATERIAL CURRENT IS HEATED TO AT LEAST TO ABOUT 450C AND IS THEN DIVIDED INTO AT LEAST TWO PARTIAL CURRENTS, ONE OF WHICH IS BURNED IN THE FORM OF A CEMENT CLINKER AND THE OTHER IS USED FOR THE MANUFACTURE OF A LOW CALCINATED HYDRAULIC BINDER. ACCORDING TO THE INVENTION, WE DRIVE FROM THE SOLID GAS CURRENT PASSING THROUGH THE INSTALLATION IN A TEMPERATURE RANGE BETWEEN 450C AND 950C A PARTIAL CURRENT WHICH IS DIVIDED IN A SEPARATE STAGE IN SOLID MATTER AND GAS AND THE SOLID MATERIAL IS COOLED THEN IT IS COOLED. TREATED IN THE FORM OF A HYDRAULIC BINDER, THE CORRESPONDING INSTALLATION INCLUDING AT LEAST ONE DUCT 5 FROM THE COMPUTER ZONE 1, 1 'FOR THE EXTRACTION OF A PARTIAL CURRENT GAS SOLID MATERIAL, A SEPARATOR GROUP 6 AND A COOLER 8. APPLICATION TO THE MANUFACTURE OF HYDRAULIC BINDERS.

Description

The present invention relates to a method and a

  installation for the manufacture of hydraulic binders.

  In the German patent application DE-OS 28 15 161, there is described a method and an installation for the manufacture of various hydraulic binders from common raw materials in a calcination process, where a raw material stream in a finely divided form is heated to at least until dehydration and the main stream is then divided into at least two partial streams, one of which is converted in the cementitious klinker calcination process while the other partial stream is derived from the process calcination, cooled in a separate cooling zone and used

  for the manufacture of a less calcined hydraulic binder.

  A suitable installation in this regard has previously been arranged and used so that from a conduit traversed by finely divided solid material and leaving the exit of a separator cyclone associated with the preheating zone or the zone of calcination, a fraction of the preheated and at least partially calcined material is derived via a switch and by means of an adjustable dosing register or an extraction device ensuring a volumetric or gravimetric dosing. In this respect we have encountered difficulties because an adjustable dosing register can often not perform with the necessary precision the division of a current

  principal of solid matter into two partial streams.

  In addition, the use of other extraction devices operating by volumetric or gravimetric dosing is also made difficult by the fact that the material stream is at temperatures between 450 and 950 ° C. Also an extraction device must

  completely closed because it exists between the extractive area

  tion and the surrounding atmosphere of pressure differences

  an order of magnitude of a few hundred millibars.

  As a result, the use of an extraction device

open forbids itself.

  Another difficulty is created by the cooling

  Particle-derived by-product formed of a finely divided material, especially also with regard to a desirable recycling of the amount of heat thus withdrawn in the circuit of the installation. The purpose of the invention is therefore to further improve the known method or the corresponding installation so as to eliminate difficulties and limitations.

aforementioned techniques.

  With the invention it has surprisingly been found that this problem could be solved in an advantageous and uncomplicated manner when from the flow of solid material and gas passing through the plant in a range of At temperatures between 450 ° C and 950 ° C, a partial stream is derived which is separated into solids and gas in an independent separator state, the solids being cooled and then being treated to form a hydraulic binder. Without encountering the difficulties manifesting itself in the exact separation of a partial flow of finely divided solid material from a stream of material and non-divided solids in the indicated temperature range the division of a solid-loaded gas stream In this way it has arrived thanks to the invention, by the bypassing of the partial flow from the stream of solids and gases of the installation and by subsequent separation in an independent separator stage under form of solids and gases, to achieve extremely

  exact inside the closed facility.

  In one embodiment of the method, it is provided that the bypass of the partial stream is carried out

  from the stream of solids and gases leaving the calcu-

  nator. The material obtained at this location has the maximum activation condition and therefore also a temperature at the upper limit of the range

  of temperatures provided according to the invention.

  In addition, it is proposed that the solid material be cooled against the current with air in a

  cooler operating by suspension in a gas.

  By using a chiller operating by suspension in a gas and connected downstream of the separator stage, it is easy to effect cooling of the finely divided solid material.

  by direct heat exchange with the cooling air.

  In this respect, most of the heat contained in the solid material is transferred to the cooling air and is reintroduced into the system circuit at a suitable location. Advantageously in this way the quantity of heat transferred to the coolant is

recycled in the installation.

  The advantage is thus obtained that the quantity of heat contained in the material derived from the calciner is recycled for the most part in the installation on the channel passing through the chiller-suspension in a gas which is connected downstream. does not result from the desirable condition of high activation and high temperature of the derived solid material, no disturbing influence on the situation of the installation as regards

concerns heat savings.

  The gas burned by the derived solid material can then be introduced into a stage of the heat exchanger which is placed downstream or, in the case of a high content of harmful substances, it can be discharged into a bypass. In this respect, it is provided in another embodiment that the fraction of the partial stream derived from the stream of gas and solids is between 1% and 30%,

preferably between 5% and 20%.

  In this respect, the surprising accuracy with which it is possible to separate a partial flow of solids from the main stream of matter is made possible by the invention in this respect.

  solid finely divided passing through the installation, corres-

  one of the important advantages of the invention.

  Another advantage is that the weight control can be performed in an uncomplicated and very advantageous manner by virtue of the fact that, in accordance with another characteristic of the invention, this regulation is effected indirectly by means of a regulation flow or throttling of the recycled gas stream from the

  separator to the plant or to the bypass.

  For this purpose, it can further be provided that the gas loaded with harmful substances and discharged into the bypass is cooled with air and if necessary by addition of water at least until the condensation of harmful substances , that the bypass dusts contained therein are separated, that the gas is removed from the installation and that the bypass dusts are added to the hydraulic binder or

  Well thrown or otherwise used.

  It is of course known, and especially exclusively to reduce the flow of harmful substances and / or the contents of harmful substances in the cement klinker, to derive from the internal circuit of a cement calcination plant a partial flow of gas, for example from the calcination zone, cool it rapidly with cooling air and if necessary with the addition of water and separate the alkaline substances, the chlorinated compounds and the sulphates which are then condensed in the form of

  dust and then unload the clean gas from the

  In this respect, the elimination or reuse of the separated dusts in the bypass device, which must be eliminated from the production process, creates difficulties (Zement-Kalk-Gips, volume 5 (1962), p.

  203, figure 11 and description right column) Such a

  bypass device for reducing the content of harmful substances in cement clinker has been described for example

  in the German patent application DE-AS 21 61 411.

  However, while in the processes and

  Bypass dusts cause not only

  loss of material but also pose problems

  environmental pollution, in the process according to the invention these dusts can be added without

  disadvantages to hydraulic binders produced by calcium

  weak nation and it is thus possible to exploit them fully. In addition it is expected that the outlet air of the chillers operating by suspension in a gas

  is introduced as tertiary air into the calciner.

  It then produces a recovery of heat extracted

  derived solid matter and simultaneously an introduc-

  efficient addition of additional tertiary air in the way

  It is particularly advantageous for the calciner

  tageux in installations that do not have a separate tertiary air duct and that must thus pass the combustion air for the calciner as excess

air through the oven.

  In addition, it is expected that, for a treatment of the unburned solid part in the form of klinker and essentially calcined in the form of a hydraulic binder, additives having hydraulic or pozzolanic properties are added and mixed together. to form a homogeneous mixture, let the free lime fraction of the mixture be extinguished with water and

  mixture is then further cooled.

  As addition materials having hydraulic properties, cement and / or blast furnace slag are used in this respect, whereas as pozzolanic additives, fly ash from thermal power stations, pozzolans are used.

and similar materials.

  An installation for carrying out the process according to the invention is characterized by a duct extending from the calciner zone for the discharge of a partial flow of gas / solid material, comprising a separator group and a cooler for material. solid finely divided. According to other features of the invention the cooler is a counter-current cooler and suspended in a gas; there is provided a conduit connecting the solid material outlet of the separator group with the cooler, a gas stop member being advantageously arranged in this duct there is provided a tertiary air duct connecting the gas outlet of the cooler with the calciner ; a flue pipe connecting the separator gas outlet to a heat exchanger or bypass is provided

  in the flue pipe there is a throttle element

  which can advantageously be remotely controlled; the countercurrent and gas-slurry cooler has two stages of cyclones and a connecting pipe in which a fan is arranged and the pipe from the separator opens into the part of the connecting pipe which connects the discharge side. fan on the first cyclone stage; the gas outlet of the separator group is connected to a mixing chamber, comprising a device for the adjustable intake of cooling air and for the injection of water, to which is connected a bypass duct provided with a scrubber bypass gas is provided groups connected downstream of the cooler for the extinction and homogenization of the hydraulic binder,

  comprising at least one mixer and, where appropriate, a

  injection system and a post-operative device

  treatment of the binder, to which is connected a dust-removing duct

  raging hot steam, which leads into the bypass pipe

  and which is equipped with an adjusting member, preferably

  the remote control, and there is also a pipe that connects the dust collector volume of the purifier

bypass gas to said groups.

  Other features and advantages of the invention

  will be highlighted in the rest of the description,

  given by way of non-limiting example, with reference to the accompanying drawings, in which: FIG. 1 is a block diagram of a calcination plant for the manufacture of hydraulic binders, comprising a conduit leaving the calciner, a separator group, a gas-suspended cooler for the derived material and a gas pipe connecting the separator to a heat exchanger, Fig. 2 is a block diagram of the same plant as in Fig. 1, but with discharge of the same. partial flow of bypass gas.

  Figure 1 shows the calcination plant

  comprising a group of cyclones 1, II, III forming the preheating zone, a calciner comprising the reaction path 1 and the separator cyclone IV, a rotary tubular furnace 2 downstream of which is placed a cooler 3, and a conduit of tertiary air 4 overlapping the oven

  tubular rotary gas outlet pipe 1 'cullet a-

  in accordance with the invention, a conduit for

  5 which opens into a separator 6 This separates the partial stream gas / solid material derived gas and solid material It is channeled using the conduit

  7 to a chiller 8 operating by suspending

  The cooler 8 comprises the two heat exchange stages arranged in the form of cyclones 9 and 10 as well as an intermediate fan 11 and a fresh air intake duct 12 arranged in the form of a siphon. Tertiary air 13 supplied by the hot air leaving the cooler is provided to introduce the heated fresh air into the reaction path 1 of the calciner

  in the area of the fuel introduction device 14.

  The gas separated from the solid material in the separator 6 is returned using the conduit 15 for example in the stage to

  cyclone II In this conduit 15 is a foreign organ

  The amount of the gas / solids partial stream which is derived from the calciner 1 by means of the bypass duct can be adjusted by means of which the weight flow rate of the recycled gas is appropriately adjusted. The finely divided material which is cooled in the cooler 8 is transferred from the cyclone 10 by means of the conduit 17 into a cooling, extinguishing and mixing unit 18 and in it, it receives an addition of water from the led 19 and optionally an addition of materials having hydraulic properties such as cement and / or slag high

  crushed furnace or additives with

  such as thermal plant fly ash or pozzolans or the like and the free lime contained in the product is extinguished by the addition of water As a result of this cooling, quenching and mixing group 18 and also following the homogenisation group 20 used to perform the final after-treatment, there is provided a dedusting duct 21 which leads to a scrubber

gas 22 (Figure 2).

  The installation of Figure 2 differs from that of Figure 1 in that the gas obtained in the

  separator 6 is evacuated from the installation via

  1 of a mixing chamber 23, a bypass line 24, a bypass gas scrubber 22 and extractor 25. The mixing chamber 23 is connected, for a cooling of the gas obtained at a temperature of about

  800 'C in the separator 6, to a cooling gas duct

  Fresh air supply 27 which is provided with a fan 26 In addition a water injection device 28 opens into the mixing chamber 23 Bypass dust separated from the gas and obtained in the gas purifier 22 is introduced by means of the duct 29, 29 'in the cooling, quenching and mixing unit 18 If necessary, bypass dust may be partly or completely mixed with the final product 31 via the bypass duct 30, case the dust is introduced by the inlet side of the homogenisation group

  Of course it is also possible to use external

  the bypass dust, for example in the form of a fertilizer, in which case the latter, as is known, is removed from the installation and can be conditioned in

  corresponding to its commercial value.

  Thanks to the invention, it arrives, in an uncomplicated and surprising way, to considerably improve and make exploitable the process and the installation

  known from the German patent application DE-OS 28 15 161.

  The difficulties have been surprisingly

  encountered at the time of the separation of a stream of finely divided and hot material with regard to the exact observation of the proportions by weight. At the same time, means have been demonstrated making it possible to cool the derived partial stream without difficulty and to recycle the the amount of heat transmitted to the cooling agent air in an efficient manner and at least in the installation at the same time. A means has been developed to avoid the enrichment of harmful substances in the plant. internal circuit of the calcination plant, then almost completely avoiding the disadvantages encountered classically and manifested by losses of material and energy In this regard should be mentioned as another advantage a possibility of effectively using the bypass dusts produced in a bypass gas scrubber and enriched in most cases by alkaline chloride compounds and / or ulfate, incorporating these dusts, if necessary completely

  or partially with weakly calcined hydraulic binders

  born and intended for the preparation of mortar.

  Finally, it has been easy to produce in a single calcination plant two different products constituting hydraulic binders, in particular cement and a mortar preparation binder, and in particular using, in an optimal manner, the

materials and energy.

  So the invention solves in a way

ideal the problem posed.

Claims (16)

  Process for the manufacture of hydraulic binders from common raw materials in a calcination process, where a raw material stream is fed to a preheating zone in a finely divided form and is heated to below about 450 ° C and is dehydrated therein, and where the main stream is then divided into at least two partial streams, one of which is converted in the subsequent calcination process into cement clinker while the other partial stream is derived from the process.   calcination, cooled in a separate cooling zone   and used for the manufacture of a hydraulic binder   less calcined, characterized in that, from the gas / solid stream passing through the plant in a temperature range of 450 ° C to 950 ° C, a partial stream is derived which is separated in an independent separator stage solid matter and gas, and that the solid material is cooled and treated   later to form a hydraulic binder.   Process according to Claim 1, characterized in that the bypass of the partial stream is carried out at   from the stream of gas / solids leaving the calcined   tor. Process according to Claim 1 or 2, characterized in that, for the cooling of the solid material, a cooler operating by means of suspension in suspension is used.   a gas and air as coolant.   4 Process according to one of claims 1 to 3,   characterized in that the gas separated from the solid material is again introduced into a stage of the heat exchanger. downstream heat -   Method according to one of claims 1 to 3,   characterized in that the gas separated from the solid material is discharged, in the case of a high content of substances harmful, in a bypass.   Process according to one of Claims 1 and 2,   characterized in that the proportion of the partial stream relative to the gas / solid stream is between   1% and 30%, preferably between 5% and 20%.   Method according to one of Claims 1 to 6,   characterized in that the quantitative regulation of the derived solid material stream is effected by regulation   quantitative carrier gas stream.   Process according to Claim 5, characterized in that the gas discharged into the bypass is cooled by means of air and, if appropriate, by the addition of water at least until the harmful substances are condensed, in that the bypass dusts are removed. contained in it are separate and in that   these are added, if necessary, to the hydraulic binder.   9 Process according to claim 3, characterized in that the air leaving the cooler is introduced as air Tertiary in the calciner.   Method according to one of claims 1 to 9,   characterized in that for the treatment of the fraction -   a substantially calcined and unburned solid material in the form of a klinker for conversion into a hydraulic binder, additives having hydraulic or pozzolanic properties are added and mixed together   to form a homogeneous mixture, in that the fraction -   lime free from the mixture is extinguished with water and in this   that it is then cooled again.   Process according to claim 10, characterized in.   what are used as additives with proprietary properties   hydraulic tees of crushed blast furnace cement and / or slag and as additives with pozzolanic properties of thermal power plant fly ash   pozzolans and similar materials.   12 Installation for the manufacture of hydraulic binders   particularly for the implementation of the process according to   one of claims 1 to 11 in a plant of   calcining a finely divided material comprising a preheater, a calciner, a klinker burning unit, a klinker cooler and a device   to transfer heat-stable solid material   treated between a preheating device and a klinker zone, characterized in that the device comprises at least one duct (5) leaving the calciner zone (1,1 ') to discharge a partial flow of gas / solid material, a separator group (6) and a cooler   (8) finely divided solid material.   13 Installation according to claim 12, characterized in that the cooler (8) is a cooler operating at   countercurrent and with suspension in a gas.   14 Installation according to claim 12, characterized in that there is provided a conduit (7) connecting the solids outlet of the separator group (6) with the cooler (8) and in which it is advantageously provided an organ stopping gas (32).   Installation according to one of claims 12 to 14,   characterized in that there is provided a tertiary air duct (13) connecting the gas outlet of the cooler (8) with the calciner (1, 1 ').   Installation according to one of Claims 12 to 15,   characterized in that there is provided an effluent gas duct (15, 24) connecting the gas outlet of the separator (6) with a   heat exchanger or with a bypass.   Plant according to Claim 16, characterized in that a throttling element (16) is advantageously provided in the effluent gas duct (15). be remotely controlled.   Installation according to one of claims 12 to 17,   characterized in that the counterflow cooler (8) with gas suspension comprises two cyclone stages (9, 10) and a connecting pipe (33) in which a fan (11) is arranged and the pipe (7) from the separator (6) opens into the portion of the connecting pipe (33) which connects the discharge side of the fan (11) to first cyclone stage (9).   19 Apparatus according to claim 12 and claim   16, characterized in that the gas outlet of the separator group (6) is connected to a mixing chamber (23), comprising a device (26, 27) for the adjustable intake of cooling air (28) as well as for the injection of water, to which is connected a bypass duct   (24) provided with a bypass gas scrubber (22).   Installation according to claim 19, characterized in that there are provided qroupes (18, 20) connected downstream of the cooler (8) for the extinction and homogenization of the hydraulic binder, comprising at least one mixer (18) and if necessary a water injection device (19) and a post-treatment device (20) of the binder, to which is connected a hot dust dedusting duct (21), which opens into the bypass pipe (24) and which is provided with an adjusting member (34), preferably being remotely controllable, and there is further provided a pipe (29, 29 ',   ) which connects the dust collecting volume of the   bypass gas (22) to said groups (18, 20).