JPS59227749A - Method and apparatus for manufacturing hydraulic binder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Prior invention [Published application of the Federal Republic of Germany (DB-O828)
15161) was the subject of a method and apparatus for producing several different hydraulic binders from several common raw materials in one firing step. heating a stream of particulate raw material to at least dewatering, subsequently dividing the stream into at least two sub-streams, and calcination of one of the two sub-streams into cement clinker in a subsequent calcination process; The other substream is branched off from the calcination step, cooled in a separate cooling zone, and used to produce a weakly calcined hydraulic binder.

Apparatus suitable for this purpose has heretofore been constructed and operated as follows. This means that from the conduit through which the finely divided solids flow, a portion of the preheated and at least partially calcined raw material is arranged via a material splitter at the outlet of the separating cyclone belonging to the preparatory zone or the calcining zone. Branched off by a regulating valve with a volumetric function or a take-off device with a volumetric or gravimetric metering function.

In that case, a control valve with a metering function is required to divide the solids stream into two partial streams 'ftF! There is a problem because 11 degrees cannot be reached. Moreover, the use of a dispensing device with volumetric or weight metering function also makes it difficult to maintain the temperature of the raw material at 45
This is difficult because the temperature is between 0 and 950°C. The extraction device must also be completely closed. This is because there is a pressure difference on the order of several hundred millibar between the extraction location and the surrounding atmosphere. The use of self-opening extraction devices is therefore prohibited.

A further source of problems is the cooling of the branched partial streams of the particulate raw material, especially considering the return of the heat released to the device into the desired flow.

The basic task of the invention is to improve the conventional method and device in such a way that, apart from some of the drawbacks mentioned above, the technical limitations are overcome.

This invention surprisingly revealed the following points. That is, for the above-mentioned purpose, a portion is separated from the gas/solid stream of the apparatus in the temperature range of 450' to 95Q°C, separated into solid and gas in another separation stage, and the solid is cooled and further processed. This is achieved advantageously and without delamination by using a hydraulic binder.

In contrast to the difficulties in accurately separating a particulate solids substream from an unseparated solids/material stream in the temperature range mentioned above, there are no significant problems in dividing and metering the solids-laden gas stream. The invention thus proposes a very precise division of quantities in a closed device by branching of the substream from the gas-solids substream of the device and subsequent separation into solids and gas in a separate separation stage. do.

In this method configuration, a branching off from the exhaust gas/solids stream of the calciner takes place.

The raw materials accumulated there have the highest degree of activity and therefore also have a temperature at the upper end of the temperature range defined according to the invention.

Furthermore, it is proposed to cool the solid by convection with air in a floating gas cooler.

Cooling of particulate solids through direct heat exchange with the cooling air is easily accomplished by the use of a floating gas cooler downstream of the separation stage. In this case, most of the heat is transferred from the solid to the cold air and then introduced again into the system of the device at a suitable point. In this way, the amount of heat supplied to the refrigerant is advantageously returned to the device again.

From the above points, an advantage arises in that most of the heat of the material branched off from the calciner is returned to the apparatus via a floating gas cooler connected downstream. Therefore, no adverse consequences for the thermoeconomic state of the device result from the desired high activity-temperature state of the branched solid.

The gas calcined from the branched solid can then be introduced into a stage located downstream of the heat exchanger and, if it is rich in harmful substances, can be conveyed to a bypass.

In yet another arrangement, the partial flow of the gas-solids stream is between 1 and 30 percent, and even between 5 and 20 percent. This kind of accuracy was made possible for the first time with this invention. This unexpected precision is one of the important advantages of the invention, which makes it possible to separate a solids substream from the particulate solids stream flowing through the device system via the method of gas stream division. Become.

What is further advantageous in that case is that the amount regulation can be carried out in the least complicated and most advantageous manner possible by the following proposal. This is done in an indirect manner by regulating or throttling the gas flow which is returned from the separator to the device or to the bypass.

In that case, the gas containing harmful substances discharged during the bypass is further cooled by adding air and possibly water until at least the harmful substances are condensed, and the bypass dust contained therein is separated. The gas can be vented and the bypass dust added to the hydraulic binder, dumped, or used separately.

Indeed, exclusively in order to reduce the amount and/or content of harmful substances circulating in the cement clinker, a partial flow is branched off from the internal circulation of the cement/calciner/system, e.g. in the area of the calcining zone. It is known to branch off the gas, quench it with the addition of cold air and optionally water, to separate the alkalis, chlorine compounds and sulphates which then condense as dust, and to discharge the purified gas from the device. The removal and subsequent use of the dust, which is then separated in the bypass device and must be eliminated from the production process, is difficult (Cement-Kallcm Gips, 1962).
Vol. 5, p. 205, Figure 11 and the article in the right column]. A bypass device of this type for reducing the content of harmful substances in cement clinker is also described, for example, in German Publication No. 21 61 411.

However, whereas in these known methods and devices the bypass dust not only causes material losses but also poses problems of deposit or utilization, the bypass dust does not come without any disadvantages according to the method according to the invention. It is added to the hydraulic binder made by mild baking and used effectively.

Furthermore, the exhaust air from the floating gas cooler is introduced into the calciner as tertiary air. In this way, the heat extracted from the branched solids is restored, and at the same time the provision of hot tertiary air in the reaction distance of the calciner is effected. This is particularly advantageous in installations which do not have a separate tertiary air conduit and in which the combustion air for the calciner must be withdrawn from the furnace in excess air.

Furthermore, in order to process the solid part which is not calcined until it becomes clinker, hydraulic or puzzolanic additives are added to the hydraulic binder and mixed with each other to form a homogeneous mixture. , the free lime portion of the mixture is slaked with water, followed by further cooling of the mixture.

In that case, cement and (
or) pulverized blast furnace slag is used, and the additives with buzolanic properties are power plant fly ash, buzolan and similar substances.

The device for carrying out the method according to the invention comprises at least one branched gas-solids partial stream from the region of the calciner, comprising a device for separating finely divided solids and a cooler. features a conduit.

Further details will be given based on figures showing some embodiments.

Figure 1 shows a reaction section 1 and a cyclone group ■, ■ forming a preheating zone with a calciner including a separation cyclone ■.
, (1) shows a firing device having a rotary kiln 2, a downstream cooler 3 and a tertiary air conduit 4 covering the rotary kiln. A branch pipe 5' according to the invention branches off from the exhaust gas pipe 1' of the calciner and leads to a separator 6. This separator separates the branched gas/solids fraction into gas and solids. The solids are fed via conduit 7 to a floating gas cooler 8 . The cooler 8 comprises two heat exchange stages formed as cyclones 9 and 10 and a ventilation fan 1 arranged between them.
1 and a new air suction pipe 12 formed in a siphon shape. The tertiary air conduit 13 to which hot cooling exhaust air is supplied is
Provision is made for introducing hot fresh air into the reaction section 1 of the calciner in the area of the fuel inlet device 14. Separator 6
The gas separated from the solids therein is returned via conduit 15 to, for example, the cyclone stage (2). In this conduit 15 there is a remotely controlled throttle element 16 by means of which the flow of the returned gas is arbitrarily regulated, so that the gases and solids branched off from the calciner 1 with the branch pipe 5 The amount of partial flow becomes adjustable.

Particulate material cooled in floating gas cooler 8 is transferred to conduit 17
cyclone 10 with a cooling, slaking and mixing device 18
into which water is added via conduit 19 and optionally a hydraulic material such as cement and/or a pusolanic addition such as ground blast furnace slag or power plant fly ash or Buzolan or the like. material is added,
Free lime entrained in the mixture is slaked by the addition of water. A steam dedusting line 21 is connected to this cooling, slaking and mixing device 18 and, if necessary, a downstream homogenizing device 2o which serves for final work-up. This water vapor dedusting conduit leads to the gas purification device 22 (second
figure).

The apparatus shown in FIG. 2 differs from the apparatus shown in FIG. 1 in the following respects. That is, the gas accumulated in the separator 6 is transferred to the mixing chamber 23, the bypass conduit 24, the bypass gas purification device 22, and the exhaust machine 2.
5 from the device.

A fresh air cooling gas conduit 27 equipped with a ventilator 26 is connected to the mixing chamber 23 in order to cool the gas accumulated in the vessel 6 at about 800°C. Furthermore, a water injection device 28 communicates with the mixing chamber 23 . Bypass dust accumulated in the gas purification device 22 and separated from the gas is passed through the conduit 29.2.
9' into the cooling, slaking and mixing device 18. In some cases, some or all of the bypass dust may be added to the finished material 31 by the branch conduit 30. For this purpose, dust is introduced into the feed side of the homogenizer 20. An impurity use of the thermal bypass dust is also possible, for example as a fertilizer, for which purpose, as is known, the bypass dust can be removed from the device and further processed according to its sales value.

With this invention it has been possible to achieve in an uncomplicated and unexpected manner a significant improvement and completion of the method and apparatus described in DE-O8 2815161.

The difficulties encountered when dividing hot particulate solids streams with respect to maintaining the proportions accurately are overcome in a surprising manner. At the same time, means are provided for easily cooling the branched partial stream, in which case at least a large portion of the heat carried by the air in the coolant is passed back into the analytical system. At the same time, a method is shown to prevent the possible increase of harmful substances in the internal circulation of the firing equipment,
The disadvantages that normally occur in this case, such as losses of material and energy, are almost completely avoided.

Another advantage here is the possibility of making full use of the bypass dust, which is mostly enriched with alkali chloride compounds and/or sulfate compounds, and which accumulates during NOx gas purification.

The RK bypass dust is optionally added in whole or in part to the weakly calcined hydraulic binder provided for mortar preparation.

As a result, two different products of hydraulic binder are produced in one and the same calcining device: cement and binder for mortar preparation. Moreover, it is manufactured using materials and energy in the best possible way.

The invention thus solves its basic problem in an ideal manner.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 shows a conduit branching from a calciner, a separation device, a floating gas cooler for cooling the branched material, and a gas conduit leading from the separator to a heat exchanger. FIG. 2 is a schematic diagram of a sintering device for producing a hydraulic binder, which is the same device as shown in FIG. . Reference numeral 8 in the figure: Cooler, 18.20: Suppression and homogenization device,
19... Water injection device, 22... Bypass purification device,
29, 29', 30... Conduit, 34... Adjustment member.

Claims (1)

[Claims] 1) A method for producing a hydraulic binder from raw materials in a firing process, in which a stream of particulate raw materials is fed into a preheating zone, in which it is heated to at least about 450°C; In case of dewatering, the stream is subsequently divided into at least two sub-streams, one of which is calcined into a cement tarinker during the subsequent course of the calcination process, and the other sub-stream is subjected to the calcination process. A method for the production of weakly calcined hydraulic binders, characterized in that a partial stream is branched off from the gas and solids stream of the apparatus in a temperature range of 450 DEG C. to 950 DEG C. 2) The method according to claim 1), wherein a partial stream is branched from the exhaust gas/solids of the calciner. 3) The method according to claim 1) or 2), which uses a floating gas cooler and air as a refrigerant for cooling the solid. 4) The method according to any one of claims 1) to 3), wherein the gas separated from the solid is sent again to the downstream stage of the heat exchanger. 5) The method according to any one of claims 1) to 3), wherein if the gas separated from the solid contains a large amount of harmful substances, it is discharged to a bypass. 6) Process according to claim 1) or 2), characterized in that the fraction of the substreams of the gas and solid streams is between 1 and 30 percent, in particular between 5 and 20 percent. 7) The method according to any one of claims 1) to 6), wherein the flow rate of the branched solid stream is adjusted by adjusting the flow rate of the carrier gas flow. 8) The gas discharged to the bypass is cooled with air and, in some cases, added water, until at least the harmful substances are condensed, and the bypass dust contained therein is separated, and in some cases, this is hydraulically bonded. Claim 5 added to the agent.
) method described. 9) The method according to claim 3), wherein the exhaust air from the cooler is introduced into the calciner as tertiary air. 10) Uncalcined into clinker, 19": Adding hydraulic or bezolanic additives to the aqueous binder for processing of the calcined solid part and mixing with each other to form a homogeneous substance,
10. A method according to claim 1, wherein the free lime content of the mixture is slaked with water and subsequently further cooled. 11) Cement and (or Fi) as hydraulic additives
11. Process according to claim 10, characterized in that the pulverized blast furnace slag is used with power plant fly ash, puzzolan and similar substances as puzzolanic additives. 12) A method of producing hydraulic binders from raw materials in a calcination process, in which a stream of finely divided raw materials is fed into a preheating zone, in which it is heated to at least about 150 C, where it is dehydrated, followed by into at least two substreams, one of which is calcined during the subsequent course of calcination to form cement clinker, and the other substream is branched off from the calcination process to produce weakly calcined water. branching off a substream from the gas and solids stream of the apparatus in a temperature range of 450°C to 950°C, used for the production of rigid binders, separating into solids and gases in a separate separation stage, and cooling the solids; The method for further processing into hydraulic composites is described with a preheater, a calciner, a clinker calciner, a clinker cooler, and a device for drawing the thermally pretreated solids between the preheating zone and the clinker zone. In an apparatus for carrying out in a firing apparatus for fine-grained raw materials having:
The device branches off from the region of the calciner (1, 1'),
at least one conduit (5) with a separating device (6) and a particulate solids cooler (8) for drawing off the solids substream;
A device comprising: 13) The cooler (8) is a convection type floating gas cooler,
The device according to claim 12). 14) Device according to claim 12, characterized in that a gas release element (32) is provided in the conduit (7) connecting the solids outlet of the separation device (6) with the cooler (8). 15) A tertiary air conduit (13) is provided which connects the gas outlet of the cooler (8) to the calciner.
The device according to any one of -14). 16) The device according to any one of claims 12) to 15), further comprising an exhaust gas conduit (15, 24) leading from the gas outlet of the separator (6) to a heat exchanger or a bypass. 17) Device according to claim 16, characterized in that a particularly remotely controllable throttling device (16) is provided in the exhaust gas conduit (15). 18) The convection/suspended gas cooler (8) has a ventilator (1) inside.
1) having two cyclone stages (9, 10) with connecting conduits (3) provided with conduits (7) leading from the separator (6) to the connecting conduit (33) section; 1) The device according to any one of 1) to 17), wherein the pressure side of the ventilation fan (11) is in the first range by this connecting conduit. 19) A mixing chamber (23) is connected to the gas outlet of the separation device (6), which has a device (2A, 27) for adjustable supply of cold air and water injection. , a bypass conduit (with a bypass gas purification device (22) in this device)
24) is connected to the device according to claim 12). 20) Hydraulic binders with at least one mixer (1 day) and optionally a device leading to the water inlet (19) and a device (2o) for after-treatment of the binder. A device (18, 20) is provided behind the cooler for slaked and homogenized water vapor, and a steam dedusting conduit (21) is connected to this device, and this steam dedusting conduit is connected to a bypass conduit (21). a conduit (29,
29', 30) Claim 12
) device described.