CA1101204A - Process for further use of direct reduction blast furnace gas - Google Patents
Process for further use of direct reduction blast furnace gasInfo
- Publication number
- CA1101204A CA1101204A CA293,251A CA293251A CA1101204A CA 1101204 A CA1101204 A CA 1101204A CA 293251 A CA293251 A CA 293251A CA 1101204 A CA1101204 A CA 1101204A
- Authority
- CA
- Canada
- Prior art keywords
- gas
- coal
- heating
- blast furnace
- plant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
- C10B57/08—Non-mechanical pretreatment of the charge, e.g. desulfurization
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B7/00—Blast furnaces
- C21B7/002—Evacuating and treating of exhaust gases
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
- C21B2100/40—Gas purification of exhaust gases to be recirculated or used in other metallurgical processes
- C21B2100/44—Removing particles, e.g. by scrubbing, dedusting
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
- C21B2100/60—Process control or energy utilisation in the manufacture of iron or steel
- C21B2100/64—Controlling the physical properties of the gas, e.g. pressure or temperature
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Manufacturing & Machinery (AREA)
- Metallurgy (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
- Coke Industry (AREA)
- Manufacture Of Iron (AREA)
Abstract
Abstract of the Disclosure Process and apparatus for pre-drying coal or for heating coal or for pre-drying and heating coal which comprises feeding hot crude blast fur-nace gas into direct physical contact with the said coal whereby heat carried by the blast furnance gas is transferred directly to the coal.
Description
2~
me invention relates to a process for further use of crude direct reduction blast furnace gas in a coal pre-heatirlg plant of a metallurgical plant, in which iron ore is being reduced by the conventional blast furnace process as well as by the process of direct reduction, and in which, if re-quired, the crude coke oven gas produced is used for making reduction gas according to Wex-German Offenlegungsschrift 2,638,348. ~ `~
This Offenlegungsschrift describes a process of direct further treatment of crude coke oven gas by partial oxidation by means of oxygen, oxygen enriched air or other gas mixtures containing oxygen, and thus conver-lo sion into a reduction gas, which is used in the shaft furnace of a metallurgi_ ca] plant. It has also been suggested to use the outlet gas from the shaft ~ ~`
furnace, among other things, for heating, e.g. as undergrate fuel gas for a coal pre-heating plant.
The present invention seeks to utilize blast furnace gas in a more ~;~
generally economic way, i.e. to use not only such blast furnace gas, which originates -from a shaft furnace, which is fed with the reduction gas from a coking plant, and which has been formed by direct conversion of the hot crude - coke oven gas, and in particular to use blast furnace gas not only for heating of a coal pre-heating plant, i.e. for burning and production of flue gas.
According to the process of the present invention one uses ~ "
directly or indirectly the sensible heat of the blast furnace gas coming from the shaft furnace for pre-heating coal, i.e. one uses crude blast furnace gas ~ `
as a heat carrying gas for direct heat transfer to the coal which is to be preheated.
~` If the pre-heating of the coal is carried out, preferably in two `
stages in a well known way, by first pre-drying and then heating the coking .. ,~
aoal, then, according to the invention, the hot, crude blast furnace gas is preferably used directly for pre-drying and/or heating of the coking coal.
If the available hot, crude blast furnace gas is not sufficient ; - 1 _ ,; , " ~ -1~12~4 for complete pre-drying and heating of the coking coal, then according to a further development of the process of the invention, the hot, crude blast furnace gas may be used for pre-drying only, whilst a fuel gas, e.g. an al-ready cooled and purified blast furnace gas is used for heating, or vice versa.
Whilst the final purification of the outlet gases from a shaft furnace (direct reduction) and a pre-heating plant normally must be carried out separately, the cost of construction for the present process can be re-duced by employing common purification for the waste gases from pre-drying - as well as from pre-heating, i.e. effectively finally purifying together the lo blast furnace gas and fuel gas used for pre-drying and pre-heating.
For this purpose it is advantageous to m~x the waste gases before the final purification.
To remove water from the waste gases, they should be cooled to condense water vapour during the final purification, which is preferably car-riad out for both gases together.
If the blast furnace gas from direct reduction, preferably in the form of waste gas from pre-drying, and the flue gas, preferably in the form of waste gas from pre-heating, are mixed in such a ratio that the composition of the resulting mixed gas corresponds to that of a conventional gas mixture of bla~t furnace gas and coke oven gas, then this mixed gas can be used as an undergrate fuel gas for batteries of coke ovens and/or for the pre-heating ~` plant for coal itself, and there is no need for a modification of the coking plant, whilst the use of direct reduction blast furnace gas only as undergrate fuel gas would necessitate a modification.
In this case it may also be advantageous to add a foreigh gas, preferably foreign flue gas, to the mixed gas, in order to obtain the desired quality for the mixed gas.
With the present invention it is also suggested, that the pre-~; :
drying and pre-heating in the fluidized bed drier and in the fluidi7ed bed .,, . . , : , . , ,: . .
z~
heater by means of hot, crude blast furnace gas and, if required, the addition-al flue gas, should be carried out under pressure.
The invention may be put into practice in various ways and two specific embodiments will be described by way of example, to illustrate the invention in which~
Figure 1 is a diagram of a plant for pre-heating coal, which, ~ ~-according to the process of the invention, in its entirety is directly operated by means of a heat carrying gas consisting of hot crude blast furnace gas, which is obtained from the direct reduction of iron ore, and lo Figure 2 is a diagram of a plant for pre-heating coal, which is operated by means of hot crude blast furnace gas, obtained from the direct reduction of iron ore, as heat carrier gas for the drier stage, and by means of flue gas, obtained from mixed gas, and/or blast furnace gas from the direct reduction of iron ore as heat carrier gas for the heating stage.
The process according to the invention for further use of direct reduction blast furnace gas will now be described by way of example for a two-stage pre-heating plant for coking coal. The process according to the inven-tion can, however, also be applied to any other method of pre-heating coal.
In the following description, ~ith reference to the schematic diagrams of the plants, of an example of an embodiment of the process according to the invention it is assumed that coking coal with about lO~o moisture will ;
be pre-heated to about 200C. The temperatures and other numerical values of the example should therefore be adjusted according to the water content of the ` coal and the desired pre-heating temperature which it is wished to achieve ;~ in any particular case.
The plant consists of a reduction furnace 8 provided with feeding means 30 for iron oxide pellets (g) and feeding means 31 for a reduction gas (i), and outlet means 32 for metallized pellets (h) and outlet means 33 for the hot crude blast furnace gas (m). The outlet means 33 are connected ~o z~
the inlet to a cyclone 17 having a gas outlet 34 and a solid outlet 35 for the dust ~d). The gas outlet 34 is connected via a blower 7 directly to an inlet 37 at the lower end of a fluidized bed tube 4. The tube 4 also has an outlet 38 at its upper end which is connected to the inlet 39 of a cyclone heater 5 which has a gas outlet 40 and a solids outlet 41 leading to a mixer 6 out of ~hich the dried coal emerges. The coal is then transported to the coke oven 42. Details of this part of the plant are given below.
The tube 4 also has a metering valve 44 at its lower end and an inlet duct 45 for admission of quenching water ~f) at its lower end.
lo The gas outlet 40 of the cyclone 5 is connected to an inlet 46 at the lower end of a fluidized bed tube 2, which is also provided with a solids metering valve 47 for coal and an inlet means 48 for ~uenching water (f). The tube ~ has an outlet 49 at its upper end which is connected to the inlet 50 of a cyclone 3 which has a gas outlet 51 and a solids outlet 52 from ~hich the coal is fed via the metering valve 44 to the bottom of the tube 4.
~le tube 2 is fed ~ith coal (a) from a feed hopper 1 via a dosing apparatus 53 and the metering vælve 47 to the bottom of the tube 2.
The gas outlet 51 of the cyclone 3 is cor~ected to the inlet 5 of a dust separator 9. The separator has an inlet 55 for warm water ~e) and an outlet 56 for used wash water (k). A pump 10 is provided for circulating the wash water. The separator also has a gas outlet 57 provided with valve means 58 for the cold purified direct reduction blast furnace gas (c).
As mentioned above the dried coal (b) emerging from the fluidized bed 4 emerges from the mixer 6. It falls onto a chain conveyor 11 which transports it to a storage bunker 12 from which it passes to a measuring bin 13 which can hold one charge for the coke oven 42.
The measuring bin feeds an intermediate chain con~Teyor 14 which in turn feeds a feed conveyor 15 which introduces the coal into the oven 42 via chutes 16.
.. .. .
Wet coal (a) is transported to a feed hopper 1, dosed in a dosing apparatus and fed into a first fluidized bed tube 2 (the so-called drier stage by means of the centrifugal feeder 47. In the fluidized bed the coal is dried to a moisture content of about 5% and heated to about 80C by means of hot heat carrying gas, which according to the invention, is hot, crude blast fur-nace gas (m), which, as shown in Figure 1, already has been cooled down to 280 C in a second fluidized bed tube 4 (the so-ealled heating stage).
At the upper end of the fluidized bed tube 2 the pre-dried coal is separated out in a cyclone 3, and is fed by gravity to the foot of the second fluidized tube 4, into which it is fed by means of the centrifugal feed-er 44. The pre-dried coking coal is heated to about 200 C in the fluidized bed tube. For this pu~pose the hot, erude blast furnace gas (m) is used, whieh originates from a reduction furnace 8, which is fed with iron oxide pellets (g) and a reduetion gas (i), which is produeed according to Offenlegungsschrift 26 38 348 and may originate from a eoke oven plant. The hot, erude blast furnaee gas is only pre-purified in a eyclone 17 and compressed at an inter-stage in the blower 7 for blast furnace gas, before it is fed into the lower end 37 of the fll~dized bed tube 4. The temperature of the hot, erude blast furnaee gas deereases by about 270 in the fluidi~ed bed tube 4, so that in the ` 20 following fluidized bed tube 2 the moist coal is being pre-dried very gently. ~`
At the upper end of the fluidized bed tube 4 the coking coal is completely ~ ~-dried at a temperature of 200 C. After separation in the cyelone heater S the coal is subsequently passed through a mixer 6 and a chain con~eyor 11 for collection in a storage bunker 12 and feeding into a downstream measuring bin 13, which has a capaeity of one oven charge. From the measuring bin 13 the preheated coal (b) is passed through an intermediate chain con~eyor 14 and a feed conveyor 15 and a chute 16 to the coke oven. me pre-drying waste gas (r) (blast furnace gas), originating from the cyclone 3, is purified in a dust separator 9. The dust separator 9 is constructed as a wet eleaner and provided , 11.2e~4 with a circulating pump 10 for the washing water (e-k). In this process the blast furnace gas ls simultaneous]y cooled and any water vapour is condensed, so that cold, purified direct reduction blast furnace gas (c) is formed. ~lus, -whilst normally the outlet gas from the pit furnace for direct reduction must subsequently be cooled from about 400C to ambient temperature, the process according to the invention utilises a large fraction of the thermal energy of the blast furnace gas for pre-heating coal.
Whilst in the plant for performing the process according to the invention sho~n in Figure 1 the blast furnace gas is arranged to flow sequen-tially through the fl~idized bed heater 4 and the fluidized drier 2, in order to obtain a relatively low temperature by exploiting the counterflow principle;
the hot, cru~e blast furnace gas can also be passed in parallel to the fluid-ized bed heater 4 and the fluidized bed drier 2. me circuit chosen for the flow of gases essentially depends on the available quantities of gas and heat as well as on the desired pre-heating temperature for the coal.
If the sensible heat available in the blast furnace gas direct reduction is insufficient for the process of pre-drying and heating, then the process of the invention is performed in a modified plant as shown in Figure 2. The plant sho~n in Figure 2 has many parts in common with that shown in Figure 1 (and these are given the same reference numerals) including the basic ` feature of the gas outlet 33 of the blast furnaces 8 being connected via a cyclone 17 to the inlet to one of the fluidized bed tubes. ' However, whereas in Figure 1 the connection is to the inlet 37 of the tube 4 and the gas outlet from that tube is connected to the inlet 46 to the tube 2, in Figure 2 the main gas stream from the furnace 8 is taken to the ~` in~et 46 of the tube 2 and the gas outlets from the tubes 4 and a proportion of the gas outlet from the tube 2, after cleaning and a proportion of the gas from the furnace 8 are supplied to the inlet 37 of the tube 2.
Thus the outlet line 34 from the cyclone 17 splits into two lines .~ .
, .
60 and 61. Line 60 feeds the inlet 46 of the tube 2 via the blower 7 whilst line 61 is connected via a valve 62, blower 21 and combustion chamber heater ;~
19 to the inlet 37 of the tube 4.
The heater 19 is fed with air ~n) by a blower 20.
me outlet 40 from the cyclone 5 splits into two lines 63 and 64, line 64 being connected to the heater 19 and line 63 being connected to a gas mixer 1~ to which the outlet 57 from the cyclone 3 is also connected.
The outlet from the mixer 18 is connected to the inlet 54 of the separator 9.
loThe outlet 57 from the separator 9 splits into two lines 66 and '~
67. ~he line 66 is connected via a valve 68 to the line 61 between the valve ~`
62 and the blower 21.
An inlet 69 is provided for foreign gas tl) to the line 6~ before the valve means 58.
In the arrangement shown in Figure 2 the hot, pre-purified crude blast furnace gas (m) is compressed at an interstage and fed to the fluidi~ed bed drier 2 only. A heat carrying gas (t~ is used to heat the coking coal in the fluidized bed heater 4. Ihe gas (t) is produced in the combustion chamber 19. The air (n) required for combustion is fed into the combustion chamber by means of a blower 20. The waste gas ~blast furnace gas) (r) from the cyc-lone drier 3 and the waste gas (flue gas) (s) from the cyclone heater 5 are mixed in the gas mixer 18, and only thereafter are they fed to the dust separa-;tor 9. me mixed gas is cooled in the dust separator 9, has its final purifi-cation and is delivered as cooled purified mixed gas (o)~ mis mixed gas (o) may be used for undergrate firing, for example for the coke ovens ~2 of the integrated coking plant. For this purpose a foreign gas (1)~ e.g. a foreign flue gas, may be added to obtain the right mixt-ure. A fraction of the mixed gas (o) may also be used as a recycled mixed gas (p) and be fed by the blower 21 to the combustion chamber 19 where it is used as a fuel gas. In this case ~.
2~4 a fraction of crude blast furnace gas (m) can be added to the recycled mixed gas (m) upstream of blower 21 vla line 61. To correctly adjust the temperature of the heat carrying gas (t), there is also provision in this plant for feeding a fraction of the waste gas (s) from the cyclone heater 5 in the form of re~
cycled vapour (q) to the combustion chamber 19. In this way the temperature of the heat carrying gas (t) at the inlet to the heating stage 4 can be ad-justed. me blower 21 provides the required compression at an interstage for the mixed gas.
The plant shown in Figure 2 assures a very economical and flexible method of operation, particularly because the final effect is a common final purification of the waste gas (s) as well as the crude blast furnace gas (r) in a single dust separator 9. The mixing of the blast furnace gas (r~ and the flue gas (s) in the gas mixer 18 not only fulfills the purpose of completely saving one unit in the plant, namely a dust separator 9; but by mixing and correct adjustment of the mixture ratio, a mixed gas can be produced, which is similar to the conventional mixture of blast furnace gas and coal gas, used for undergrate firing of batteries of coke ovens. For this purpose foreign flue gas (1) can be added when required. The production of such a mixed gas is particularly important if, as suggested in patent application P 26 38 348, all ` 20 of the crude coal gas available in a metallurgical plant is used for produc~
tion of reducing gas, so that no purified coal gas is available for the pur-pose of undergrate firing. It would of course be technically possible to use direct reduction blast furnace gas, which has a calorific value intermediate ~ between that of coal gas and conventional blast furnace gas mixture, for under-;~ grate firing of the coke oven. This, however, would entail a different layout and distribution of the regenerators in a battery of coke ovens. For this reason it is particularly advantageous to provide a mixed gas, which is simi-lar to and interchangeable with the con~entional gas mixture. The necessary mixture ratio can be adjusted without difficulty, and with addition of foreign 2~L
flue gas (1), if required, in gas mixer 18. The production o-f mixed gas from direct reduction blast furnace gas and flue gas, obtained from plant for pre-heating of coal according to the invention or a different source of flue gas, is of technical importance for new plants as well as for extension or conver-sion to the process proposed in patent application P ~6 38 348 for direct :~
further treatment of coal gas, because in no case is it necessary to inter-fere with the method of the process or the construction of the co~e oven.
,: ~
me invention relates to a process for further use of crude direct reduction blast furnace gas in a coal pre-heatirlg plant of a metallurgical plant, in which iron ore is being reduced by the conventional blast furnace process as well as by the process of direct reduction, and in which, if re-quired, the crude coke oven gas produced is used for making reduction gas according to Wex-German Offenlegungsschrift 2,638,348. ~ `~
This Offenlegungsschrift describes a process of direct further treatment of crude coke oven gas by partial oxidation by means of oxygen, oxygen enriched air or other gas mixtures containing oxygen, and thus conver-lo sion into a reduction gas, which is used in the shaft furnace of a metallurgi_ ca] plant. It has also been suggested to use the outlet gas from the shaft ~ ~`
furnace, among other things, for heating, e.g. as undergrate fuel gas for a coal pre-heating plant.
The present invention seeks to utilize blast furnace gas in a more ~;~
generally economic way, i.e. to use not only such blast furnace gas, which originates -from a shaft furnace, which is fed with the reduction gas from a coking plant, and which has been formed by direct conversion of the hot crude - coke oven gas, and in particular to use blast furnace gas not only for heating of a coal pre-heating plant, i.e. for burning and production of flue gas.
According to the process of the present invention one uses ~ "
directly or indirectly the sensible heat of the blast furnace gas coming from the shaft furnace for pre-heating coal, i.e. one uses crude blast furnace gas ~ `
as a heat carrying gas for direct heat transfer to the coal which is to be preheated.
~` If the pre-heating of the coal is carried out, preferably in two `
stages in a well known way, by first pre-drying and then heating the coking .. ,~
aoal, then, according to the invention, the hot, crude blast furnace gas is preferably used directly for pre-drying and/or heating of the coking coal.
If the available hot, crude blast furnace gas is not sufficient ; - 1 _ ,; , " ~ -1~12~4 for complete pre-drying and heating of the coking coal, then according to a further development of the process of the invention, the hot, crude blast furnace gas may be used for pre-drying only, whilst a fuel gas, e.g. an al-ready cooled and purified blast furnace gas is used for heating, or vice versa.
Whilst the final purification of the outlet gases from a shaft furnace (direct reduction) and a pre-heating plant normally must be carried out separately, the cost of construction for the present process can be re-duced by employing common purification for the waste gases from pre-drying - as well as from pre-heating, i.e. effectively finally purifying together the lo blast furnace gas and fuel gas used for pre-drying and pre-heating.
For this purpose it is advantageous to m~x the waste gases before the final purification.
To remove water from the waste gases, they should be cooled to condense water vapour during the final purification, which is preferably car-riad out for both gases together.
If the blast furnace gas from direct reduction, preferably in the form of waste gas from pre-drying, and the flue gas, preferably in the form of waste gas from pre-heating, are mixed in such a ratio that the composition of the resulting mixed gas corresponds to that of a conventional gas mixture of bla~t furnace gas and coke oven gas, then this mixed gas can be used as an undergrate fuel gas for batteries of coke ovens and/or for the pre-heating ~` plant for coal itself, and there is no need for a modification of the coking plant, whilst the use of direct reduction blast furnace gas only as undergrate fuel gas would necessitate a modification.
In this case it may also be advantageous to add a foreigh gas, preferably foreign flue gas, to the mixed gas, in order to obtain the desired quality for the mixed gas.
With the present invention it is also suggested, that the pre-~; :
drying and pre-heating in the fluidized bed drier and in the fluidi7ed bed .,, . . , : , . , ,: . .
z~
heater by means of hot, crude blast furnace gas and, if required, the addition-al flue gas, should be carried out under pressure.
The invention may be put into practice in various ways and two specific embodiments will be described by way of example, to illustrate the invention in which~
Figure 1 is a diagram of a plant for pre-heating coal, which, ~ ~-according to the process of the invention, in its entirety is directly operated by means of a heat carrying gas consisting of hot crude blast furnace gas, which is obtained from the direct reduction of iron ore, and lo Figure 2 is a diagram of a plant for pre-heating coal, which is operated by means of hot crude blast furnace gas, obtained from the direct reduction of iron ore, as heat carrier gas for the drier stage, and by means of flue gas, obtained from mixed gas, and/or blast furnace gas from the direct reduction of iron ore as heat carrier gas for the heating stage.
The process according to the invention for further use of direct reduction blast furnace gas will now be described by way of example for a two-stage pre-heating plant for coking coal. The process according to the inven-tion can, however, also be applied to any other method of pre-heating coal.
In the following description, ~ith reference to the schematic diagrams of the plants, of an example of an embodiment of the process according to the invention it is assumed that coking coal with about lO~o moisture will ;
be pre-heated to about 200C. The temperatures and other numerical values of the example should therefore be adjusted according to the water content of the ` coal and the desired pre-heating temperature which it is wished to achieve ;~ in any particular case.
The plant consists of a reduction furnace 8 provided with feeding means 30 for iron oxide pellets (g) and feeding means 31 for a reduction gas (i), and outlet means 32 for metallized pellets (h) and outlet means 33 for the hot crude blast furnace gas (m). The outlet means 33 are connected ~o z~
the inlet to a cyclone 17 having a gas outlet 34 and a solid outlet 35 for the dust ~d). The gas outlet 34 is connected via a blower 7 directly to an inlet 37 at the lower end of a fluidized bed tube 4. The tube 4 also has an outlet 38 at its upper end which is connected to the inlet 39 of a cyclone heater 5 which has a gas outlet 40 and a solids outlet 41 leading to a mixer 6 out of ~hich the dried coal emerges. The coal is then transported to the coke oven 42. Details of this part of the plant are given below.
The tube 4 also has a metering valve 44 at its lower end and an inlet duct 45 for admission of quenching water ~f) at its lower end.
lo The gas outlet 40 of the cyclone 5 is connected to an inlet 46 at the lower end of a fluidized bed tube 2, which is also provided with a solids metering valve 47 for coal and an inlet means 48 for ~uenching water (f). The tube ~ has an outlet 49 at its upper end which is connected to the inlet 50 of a cyclone 3 which has a gas outlet 51 and a solids outlet 52 from ~hich the coal is fed via the metering valve 44 to the bottom of the tube 4.
~le tube 2 is fed ~ith coal (a) from a feed hopper 1 via a dosing apparatus 53 and the metering vælve 47 to the bottom of the tube 2.
The gas outlet 51 of the cyclone 3 is cor~ected to the inlet 5 of a dust separator 9. The separator has an inlet 55 for warm water ~e) and an outlet 56 for used wash water (k). A pump 10 is provided for circulating the wash water. The separator also has a gas outlet 57 provided with valve means 58 for the cold purified direct reduction blast furnace gas (c).
As mentioned above the dried coal (b) emerging from the fluidized bed 4 emerges from the mixer 6. It falls onto a chain conveyor 11 which transports it to a storage bunker 12 from which it passes to a measuring bin 13 which can hold one charge for the coke oven 42.
The measuring bin feeds an intermediate chain con~Teyor 14 which in turn feeds a feed conveyor 15 which introduces the coal into the oven 42 via chutes 16.
.. .. .
Wet coal (a) is transported to a feed hopper 1, dosed in a dosing apparatus and fed into a first fluidized bed tube 2 (the so-called drier stage by means of the centrifugal feeder 47. In the fluidized bed the coal is dried to a moisture content of about 5% and heated to about 80C by means of hot heat carrying gas, which according to the invention, is hot, crude blast fur-nace gas (m), which, as shown in Figure 1, already has been cooled down to 280 C in a second fluidized bed tube 4 (the so-ealled heating stage).
At the upper end of the fluidized bed tube 2 the pre-dried coal is separated out in a cyclone 3, and is fed by gravity to the foot of the second fluidized tube 4, into which it is fed by means of the centrifugal feed-er 44. The pre-dried coking coal is heated to about 200 C in the fluidized bed tube. For this pu~pose the hot, erude blast furnace gas (m) is used, whieh originates from a reduction furnace 8, which is fed with iron oxide pellets (g) and a reduetion gas (i), which is produeed according to Offenlegungsschrift 26 38 348 and may originate from a eoke oven plant. The hot, erude blast furnaee gas is only pre-purified in a eyclone 17 and compressed at an inter-stage in the blower 7 for blast furnace gas, before it is fed into the lower end 37 of the fll~dized bed tube 4. The temperature of the hot, erude blast furnaee gas deereases by about 270 in the fluidi~ed bed tube 4, so that in the ` 20 following fluidized bed tube 2 the moist coal is being pre-dried very gently. ~`
At the upper end of the fluidized bed tube 4 the coking coal is completely ~ ~-dried at a temperature of 200 C. After separation in the cyelone heater S the coal is subsequently passed through a mixer 6 and a chain con~eyor 11 for collection in a storage bunker 12 and feeding into a downstream measuring bin 13, which has a capaeity of one oven charge. From the measuring bin 13 the preheated coal (b) is passed through an intermediate chain con~eyor 14 and a feed conveyor 15 and a chute 16 to the coke oven. me pre-drying waste gas (r) (blast furnace gas), originating from the cyclone 3, is purified in a dust separator 9. The dust separator 9 is constructed as a wet eleaner and provided , 11.2e~4 with a circulating pump 10 for the washing water (e-k). In this process the blast furnace gas ls simultaneous]y cooled and any water vapour is condensed, so that cold, purified direct reduction blast furnace gas (c) is formed. ~lus, -whilst normally the outlet gas from the pit furnace for direct reduction must subsequently be cooled from about 400C to ambient temperature, the process according to the invention utilises a large fraction of the thermal energy of the blast furnace gas for pre-heating coal.
Whilst in the plant for performing the process according to the invention sho~n in Figure 1 the blast furnace gas is arranged to flow sequen-tially through the fl~idized bed heater 4 and the fluidized drier 2, in order to obtain a relatively low temperature by exploiting the counterflow principle;
the hot, cru~e blast furnace gas can also be passed in parallel to the fluid-ized bed heater 4 and the fluidized bed drier 2. me circuit chosen for the flow of gases essentially depends on the available quantities of gas and heat as well as on the desired pre-heating temperature for the coal.
If the sensible heat available in the blast furnace gas direct reduction is insufficient for the process of pre-drying and heating, then the process of the invention is performed in a modified plant as shown in Figure 2. The plant sho~n in Figure 2 has many parts in common with that shown in Figure 1 (and these are given the same reference numerals) including the basic ` feature of the gas outlet 33 of the blast furnaces 8 being connected via a cyclone 17 to the inlet to one of the fluidized bed tubes. ' However, whereas in Figure 1 the connection is to the inlet 37 of the tube 4 and the gas outlet from that tube is connected to the inlet 46 to the tube 2, in Figure 2 the main gas stream from the furnace 8 is taken to the ~` in~et 46 of the tube 2 and the gas outlets from the tubes 4 and a proportion of the gas outlet from the tube 2, after cleaning and a proportion of the gas from the furnace 8 are supplied to the inlet 37 of the tube 2.
Thus the outlet line 34 from the cyclone 17 splits into two lines .~ .
, .
60 and 61. Line 60 feeds the inlet 46 of the tube 2 via the blower 7 whilst line 61 is connected via a valve 62, blower 21 and combustion chamber heater ;~
19 to the inlet 37 of the tube 4.
The heater 19 is fed with air ~n) by a blower 20.
me outlet 40 from the cyclone 5 splits into two lines 63 and 64, line 64 being connected to the heater 19 and line 63 being connected to a gas mixer 1~ to which the outlet 57 from the cyclone 3 is also connected.
The outlet from the mixer 18 is connected to the inlet 54 of the separator 9.
loThe outlet 57 from the separator 9 splits into two lines 66 and '~
67. ~he line 66 is connected via a valve 68 to the line 61 between the valve ~`
62 and the blower 21.
An inlet 69 is provided for foreign gas tl) to the line 6~ before the valve means 58.
In the arrangement shown in Figure 2 the hot, pre-purified crude blast furnace gas (m) is compressed at an interstage and fed to the fluidi~ed bed drier 2 only. A heat carrying gas (t~ is used to heat the coking coal in the fluidized bed heater 4. Ihe gas (t) is produced in the combustion chamber 19. The air (n) required for combustion is fed into the combustion chamber by means of a blower 20. The waste gas ~blast furnace gas) (r) from the cyc-lone drier 3 and the waste gas (flue gas) (s) from the cyclone heater 5 are mixed in the gas mixer 18, and only thereafter are they fed to the dust separa-;tor 9. me mixed gas is cooled in the dust separator 9, has its final purifi-cation and is delivered as cooled purified mixed gas (o)~ mis mixed gas (o) may be used for undergrate firing, for example for the coke ovens ~2 of the integrated coking plant. For this purpose a foreign gas (1)~ e.g. a foreign flue gas, may be added to obtain the right mixt-ure. A fraction of the mixed gas (o) may also be used as a recycled mixed gas (p) and be fed by the blower 21 to the combustion chamber 19 where it is used as a fuel gas. In this case ~.
2~4 a fraction of crude blast furnace gas (m) can be added to the recycled mixed gas (m) upstream of blower 21 vla line 61. To correctly adjust the temperature of the heat carrying gas (t), there is also provision in this plant for feeding a fraction of the waste gas (s) from the cyclone heater 5 in the form of re~
cycled vapour (q) to the combustion chamber 19. In this way the temperature of the heat carrying gas (t) at the inlet to the heating stage 4 can be ad-justed. me blower 21 provides the required compression at an interstage for the mixed gas.
The plant shown in Figure 2 assures a very economical and flexible method of operation, particularly because the final effect is a common final purification of the waste gas (s) as well as the crude blast furnace gas (r) in a single dust separator 9. The mixing of the blast furnace gas (r~ and the flue gas (s) in the gas mixer 18 not only fulfills the purpose of completely saving one unit in the plant, namely a dust separator 9; but by mixing and correct adjustment of the mixture ratio, a mixed gas can be produced, which is similar to the conventional mixture of blast furnace gas and coal gas, used for undergrate firing of batteries of coke ovens. For this purpose foreign flue gas (1) can be added when required. The production of such a mixed gas is particularly important if, as suggested in patent application P 26 38 348, all ` 20 of the crude coal gas available in a metallurgical plant is used for produc~
tion of reducing gas, so that no purified coal gas is available for the pur-pose of undergrate firing. It would of course be technically possible to use direct reduction blast furnace gas, which has a calorific value intermediate ~ between that of coal gas and conventional blast furnace gas mixture, for under-;~ grate firing of the coke oven. This, however, would entail a different layout and distribution of the regenerators in a battery of coke ovens. For this reason it is particularly advantageous to provide a mixed gas, which is simi-lar to and interchangeable with the con~entional gas mixture. The necessary mixture ratio can be adjusted without difficulty, and with addition of foreign 2~L
flue gas (1), if required, in gas mixer 18. The production o-f mixed gas from direct reduction blast furnace gas and flue gas, obtained from plant for pre-heating of coal according to the invention or a different source of flue gas, is of technical importance for new plants as well as for extension or conver-sion to the process proposed in patent application P ~6 38 348 for direct :~
further treatment of coal gas, because in no case is it necessary to inter-fere with the method of the process or the construction of the co~e oven.
,: ~
Claims (24)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for pre-drying coal or for heating coal or for pre-drying and heating coal which comprises feeding hot crude blast furnace gas into direct physical contact with the said coal whereby heat carried by the blast furnace gas is transferred directly to the coal.
2. A process for further use of crude direct reduction blast furnace gas in a coal pre-heating plant of a metallurgical plant, in which iron ore is being reduced by the conventional blast furnace process as well as by the pro-cess of direct reduction, by using directly or indirectly the sensible heat of the blast furnace gas coming from the furnace for pre-heating of coal where-by the blast furnace gas is used as a heat carrying gas.
3. A process as claimed in Claim 2 in which the pre-heating of the coal is carried out in two stages, by first pre-drying and then heating the coking coal, and in which the hot, crude blast furnace gas is used directly for pre-drying and/or heating of the coking coal.
4. A process as claimed in Claim 3 in which the hot, crude blast furnace gas is used for pre-drying, and in which a heat carrying gas produced by burning of a fuel gas is used for heating, or vice versa.
5. A process as claimed in Claim 4 in which the fuel gas comprises an already cooled and purified blast furnace gas.
6. A process as claimed in Claim 1, in which waste gases from pre-drying as well as from pre-heating are finally purified together.
7. A process as claimed in Claim 6, in which the waste gases are mixed before final purification.
8. A process as claimed in Claim 7 in which the waste gases are cooled to condense water vapour during their final purification.
9. A process as claimed in Claim 2, in which the blast furnace gas from direct reduction in the form of waste gas from pre-drying, and flue gas in the form of waste gas from heating, are mixed in such a ratio that the composition of the resulting mixed gas corresponds to that of a conventional gas mixture of blast furnace gas and coke oven gas.
10. A process as claimed in Claim 9, in which a foreign flue gas is added to the mixed gas.
11. A process as claimed in Claim 9, in which the mixed gas is used as a replacement for conventional mixed gas for undergrate firing in a battery of coke ovens integrated with a metallurgical plant and/or for a coal pre-heating plant.
12. A process as claimed in Claim 1 in which the pre-drying and heating are carried out in a fluidized bed dryer and in a fluidized bed heater.
13. A process as claimed in Claim 1 which is carried out under pressure.
14. A process as claimed in Claim 4 in which the fuel gas used consists of mixed gas recycled from the plant and compressed at an interstage.
15. A process as claimed in Claim 4 in which vapours recycled from the heating stage are added to a flue gas produced to form the heat carrying gas.
16. A metallurgical plant comprising at least one blast furnace, at least one battery of coke ovens, coal drying means arranged to dry the coal before it is fed to the coke oven, coal pre-heating means arranged to pre-heat the dried coal, means for feeding the dried heated coal to the coke ovens and means for feeding hot crude blast furnace gas into direct physical contact with the coal in the coal drying means or in the coal pre-heating means or in both means.
17. A plant as claimed in Claim 16 in which the blast furnace is a direct reduction furnace.
18. A plant as claimed in Claim 16 in which the coal drying means comprise fluidized bed tubes and the coal pre-heating means comprise fluid-ized bed tubes.
19. A plant as claimed in Claim 16 in which exhaust gas from the drying means or the heating means or both are fed to a dust separator and cooler and means are provided for supplying outlet gas from the separator to an undergrate burner of the coke ovens.
20. A plant as claimed in Claim 16 in which the means for feeding the hot crude blast furnace gas are connected to the coal pre-heating means having a gas outlet, the gas outlet being connected to the coal drying means.
21. A plant as claimed in Claim 20 in which the gas outlet from the coal drying means is connected to a dust separator and gas cooler.
22. A plant as claimed in Claim 16, in which the means for feeding the hot crude blast furnace gas are connected to the coal drying means and via a combustion chamber to the coal heating means and a gas outlet from the coal pre-heating means is also connected to the combustion chamber.
23. A plant as claimed in Claim 22 in which the gas outlet from the coal drying means is connected to a gas mixer as is a branch from the gas outlet from the coal drying means and the gas mixer feeds a dust separator and cooler, a branch from the gas outlet of which is connected to the combustion chamber.
24. A plant as claimed in Claim 22 or Claim 23 in which means are provided for supplying foreign flue or fuel gas to the combustion chamber.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2657249.6 | 1976-12-17 | ||
| DE2657249A DE2657249C3 (en) | 1976-12-17 | 1976-12-17 | Process for the further use of raw furnace gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1101204A true CA1101204A (en) | 1981-05-19 |
Family
ID=5995805
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA293,251A Expired CA1101204A (en) | 1976-12-17 | 1977-12-16 | Process for further use of direct reduction blast furnace gas |
Country Status (16)
| Country | Link |
|---|---|
| JP (1) | JPS5381501A (en) |
| AT (1) | AT363966B (en) |
| AU (1) | AU512808B2 (en) |
| BR (1) | BR7708356A (en) |
| CA (1) | CA1101204A (en) |
| CH (1) | CH634345A5 (en) |
| DD (1) | DD133569A5 (en) |
| DE (1) | DE2657249C3 (en) |
| ES (1) | ES465002A1 (en) |
| FR (1) | FR2374400A1 (en) |
| GB (1) | GB1593527A (en) |
| NL (1) | NL7714011A (en) |
| PL (1) | PL120652B1 (en) |
| SE (1) | SE7713819L (en) |
| SU (1) | SU822758A3 (en) |
| ZA (1) | ZA777247B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2816476C3 (en) * | 1978-04-15 | 1980-10-09 | Didier Engineering Gmbh, 4300 Essen | Process for recovering waste heat from coke ovens |
| AT406964B (en) * | 1998-03-11 | 2000-11-27 | Voest Alpine Ind Anlagen | METHOD FOR THE PRODUCTION OF LIQUID PIG IRON AND / OR STEEL PRE-PRODUCTS |
| WO2004101829A2 (en) | 2003-05-15 | 2004-11-25 | Hylsa, S.A. De C.V. | Method and apparatus for improved use of primary energy sources in integrated steel plants |
| RU2501838C2 (en) * | 2012-03-12 | 2013-12-20 | Открытое акционерное общество "Восточный научно-исследовательский углехимический институт" (ОАО "ВУХИН") | Method of preparing coal charge for coking |
| CN106118697A (en) * | 2016-08-12 | 2016-11-16 | 田东昊润新材料科技有限公司 | The brown coal continuous way coker of heat energy recycling |
| CN111485060B (en) * | 2020-05-27 | 2023-06-27 | 沈阳东大山汇环境科技有限公司 | Self-generating gas circulation no-tail gas emission steel scrap smelting system and steel smelting method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB407665A (en) * | 1932-06-17 | 1934-03-22 | Pierre Eugene Henri Forsans | Improvements in or relating to the treatment of coal and like materials |
| DE1187584B (en) * | 1954-07-30 | 1965-02-25 | Steinmueller Gmbh L & C | Process for pre-drying coal |
| GB1149758A (en) * | 1966-04-14 | 1969-04-23 | Inst Energetik | Process and apparatus for the coking of pit coal |
-
1976
- 1976-12-17 DE DE2657249A patent/DE2657249C3/en not_active Expired
-
1977
- 1977-11-11 CH CH1377077A patent/CH634345A5/en not_active IP Right Cessation
- 1977-11-30 SU SU772547451A patent/SU822758A3/en active
- 1977-12-05 ZA ZA00777247A patent/ZA777247B/en unknown
- 1977-12-05 JP JP14520677A patent/JPS5381501A/en active Pending
- 1977-12-06 SE SE7713819A patent/SE7713819L/en not_active Application Discontinuation
- 1977-12-13 AU AU31500/77A patent/AU512808B2/en not_active Expired
- 1977-12-13 ES ES465002A patent/ES465002A1/en not_active Expired
- 1977-12-15 PL PL1977202979A patent/PL120652B1/en unknown
- 1977-12-15 DD DD7700202664A patent/DD133569A5/en unknown
- 1977-12-15 BR BR7708356A patent/BR7708356A/en unknown
- 1977-12-16 FR FR7738089A patent/FR2374400A1/en active Granted
- 1977-12-16 NL NL7714011A patent/NL7714011A/en not_active Application Discontinuation
- 1977-12-16 AT AT0902677A patent/AT363966B/en not_active IP Right Cessation
- 1977-12-16 GB GB52481/77A patent/GB1593527A/en not_active Expired
- 1977-12-16 CA CA293,251A patent/CA1101204A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ZA777247B (en) | 1978-09-27 |
| ES465002A1 (en) | 1978-09-01 |
| PL120652B1 (en) | 1982-03-31 |
| FR2374400B1 (en) | 1980-06-13 |
| AU3150077A (en) | 1979-06-21 |
| DD133569A5 (en) | 1979-01-10 |
| AU512808B2 (en) | 1980-10-30 |
| GB1593527A (en) | 1981-07-15 |
| SU822758A3 (en) | 1981-04-15 |
| PL202979A1 (en) | 1978-08-14 |
| ATA902677A (en) | 1981-02-15 |
| BR7708356A (en) | 1978-07-25 |
| NL7714011A (en) | 1978-06-20 |
| JPS5381501A (en) | 1978-07-19 |
| CH634345A5 (en) | 1983-01-31 |
| DE2657249C3 (en) | 1980-09-04 |
| DE2657249A1 (en) | 1978-07-06 |
| SE7713819L (en) | 1978-06-18 |
| FR2374400A1 (en) | 1978-07-13 |
| AT363966B (en) | 1981-09-10 |
| DE2657249B2 (en) | 1980-01-10 |
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