KR20130087401A - Method and device for regulating the temperature of process gases from plants for raw iron production for use in an expansion turbine - Google Patents

Abstract

A method and apparatus are provided for controlling the temperature of process gas 12 from a pig iron manufacturing plant for use in expansion turbine 34, wherein the inlet temperature of process gas 12 is expanded upon entering expansion turbine 34. Adjusted so as not to fall below the minimum inlet temperature at which condensation occurs in the turbine, and / or the process gas 12 enters the low pressure gas accumulator 13 when the process gas coming from the expansion turbine is allowed to accumulate for the accumulator. It is characterized in that it is cooled so as not to exceed the inlet temperature. In this way, at least cooling of the exhaust gas below the condensation temperature when exiting the expansion turbine can be prevented or the use of the exhaust gas cooler for introduction of the exhaust gas into the low pressure gas accumulator can be avoided.

Description

METHODS AND DEVICE FOR REGULATING THE TEMPERATURE OF PROCESS GASES FROM PLANTS FOR RAW IRON PRODUCTION FOR USE IN AN EXPANSION TURBINE}

For the production of pig iron, which is also intended to include the production of products similar to pig iron, there are essentially two known commonly adopted processes, namely a blast furnace process and a melt reduction process.

In the blast furnace process, pig iron is first produced from iron ore with the aid of coke. Scrap may also additionally be used. Thereafter, steel is produced from pig iron by an additional process. Iron ores in the form of lump ore, pellets or sinters are the reducing agents (usually coke or other coal in the form of pulverized coal blowing plants) and additional components (limestone, slag forming flux). Etc.) to form a so-called blast furnace charge, which is then charged into the blast furnace. The blast furnace reacts with the hot air in the countercurrent known as the hot blast, a stock column containing blast furnace charges. By burning carbon from the coke, the heat needed for the reaction is produced with carbon monoxide and hydrogen representing a significant portion of the reducing gas and flows through the blast furnace charging material to reduce the iron ore. The resultant are pig iron and slag, which are periodically tapped off.

In so-called oxygen blast furnaces, also referred to as top-gas or blast furnaces with blast furnace gas return, coral containing gas having an oxygen fraction (O ₂ ) of more than 80% is blown into the blast furnace during gasification of coke or coal.

For gas leaving the blast furnace known as top gas or blast furnace gas, gas purification must be provided (eg, dust separator and / or cyclone in combination with a wet scrubber, bag-filter unit or hot gas filter). . Furthermore, in the case of oxygen blast furnaces, the removal of CO ₂ by means of compressors, preferably aftercoolers, for the off-gas returned to the blast furnace, and also by pressure-swing adsorption, usually according to the prior art. Apparatus for is typically provided.

A further option for the design of the blast furnace process is a combustion chamber for partial combustion with a heater and / or oxygen for the reducing gas.

및 FINEX

프로세스)가 여기서 언급될 수 있다.
The disadvantages of the blast furnace are the high emissions of carbon dioxide and the requirements to be met by the materials used. Since the iron carriers and coke used must be lumpy and hard, sufficient voids remain in the blast furnace charging material to ensure that blown air flows through it. CO ₂ emissions represent serious environmental pollution. Thus, there is an effort to replace the route. Sponge iron manufacturing based on natural gas (MIDREX, HYL, FINMET) and also a melt reduction process (COREX

And FINEX

Process) can be mentioned here.

In the case of melt reduction, one or more reduction reactors are used in which the carrier of the melt gasifier and iron ore (lump ore, pellets, sintered product) from which hot liquid metal is produced is reduced to reducing gas, The reducing gas is produced in the melt gasifier by gasifying coal (and possibly small fractions of coke) with oxygen (90% or more).

In the melt reduction process, also generally provided

A gas purification plant (on the one hand, for the stationary gas from the reduction reactor, on the other hand, for the reducing gas from the melt gasifier),

A compressor for reducing gas returned into the reduction reactor, preferably having an aftercooler,

-Apparatus for the removal of CO ₂ , usually by pressure swing adsorption according to the prior art,

And optionally, a combustion chamber for partial combustion with a heater and / or oxygen for the reducing gas.

프로세스는 2단 용융 환원 프로세스이다. 용융 환원은 용융 환원 프로세스(주 환원)와 직접 환원의 프로세스(해면철로의 철의 사전 환원)를 조합한다.
COREX

The process is a two stage melt reduction process. Melt reduction combines a melt reduction process (main reduction) and a process of direct reduction (pre-reduction of iron to sponge iron).

프로세스는 본질적으로 COREX

프로세스에 대응하지만, 철광석은 분광으로서 도입된다.
Similarly known FINEX

The process is essentially COREX

Although corresponding to the process, iron ore is introduced as spectroscopy.

Process gases derived from processes of pig iron manufacturing or synthesis gas production are often referred to as "export gases" because they can no longer be used. This in particular serves as a term for that part of the top gas derived from the process of pig iron manufacturing, which is generally cooled in a waste heat boiler and is also generally dusted, in particular dry dust removed.

플랜트의 노정 가스로부터 건식 먼지 제거 및 열 추출 이후에, 가스는 대략 150 내지 250℃의 온도 및 전형적으로 3 bar_g의 압력을 갖는다.
COREX

After dry dust removal and heat extraction from the plant's top gas, the gas has a temperature of approximately 150 to 250 ° C. and a pressure of typically 3 bar _g .

플랜트의 노정 가스는 대략적으로 이하의 조성을 갖는다.COREX after dry dust removal and heat extraction

The top gas of the plant has approximately the following composition.

CO: 38.5% by volume

CO ₂ : 31.6 volume%

H ₂ : 15.3% by volume

H ₂ O: 11.1% by volume

CH ₄ : 1.5% by volume

N ₂ : 2.0% by volume

The exhaust gas can be compressed, for example by a one or two stage radial compressor, and then cooled, in order to allow it to be used further or to be stored immediately as fuel gas.

However, the energy content, compression and thermal energy of the exhaust gases can also be used for power generation in so-called expansion turbines or top gas recovery turbines (TRTs). The exhaust gas has a lower pressure and lower temperature after the expansion turbine than before the expansion turbine.

C-3000 플랜트의 경우에, COREX with exhaust gas production of approximately 327 000 Nm ³ / h, dry dust removal, expansion turbine with 85% efficiency and a generator connected to it with efficiency of 97%

In the case of the C-3000 plant,

When the exhaust gas leaves the expansion turbine, the following outlet temperature and pressure for the exhaust gas and the generated power and condensate generated in the expansion turbine are obtained at the inlet temperature and pressure specified below-and the exhaust composition as provided above -.

Inlet pressure
[bar _g ] 3 3 3 3 3 3 3 Inlet temperature
[° C] 250 200 150 146.5 100 50 40 Outlet pressure
[bar _g ] 0.15 0.15 0.15 0.15 0.15 0.15 0.15 Outlet temperature
[° C] 136 95 54 51 46 8 -6 power
[MW] 15.6 14.1 12.6 12.5 11.7 9.4 8.8 Condensate
[t / h] 0 0 0 0 7.4 27.1 28.4

Because of the temperature loss of the exhaust gas line, the actual temperature may deviate from the temperature specified above and below. The operating parameters of the expansion turbine can likewise be changed based on the gas composition of the exhaust gas and thus deviate from the above mentioned parameters.

플랜트의 노정 가스를 위한 건식 먼지 제거 대신에 실행되면, 이하의 통상의 값이 얻어진다.Wet Scrubs COREX

If carried out instead of dry dust removal for the plant's top gas, the following typical values are obtained.

Inlet pressure
[bar _g ] 1.5 Inlet temperature
[° C] 40 Outlet pressure
[bar _g ] 0.15 Outlet temperature
[° C] 12 power
[MW] 5.9 Condensate
[t / h] 4.1

If the inlet temperature of the exhaust gas when entering the expansion turbine falls below a temperature of approximately 150 ° C., specifically below 146.5 ° C., the exit temperature of the exhaust gas when leaving the expansion turbine is below the condensation temperature of 51 ° C. Degrades. This leads to droplet collisions and caked precipitates in the expansion turbine due to the condensation of dust and possibly polycyclic aromatic hydrocarbons (PAH). This leads to a reduction in the service life of the expansion turbine and the expansion turbine must be shut down every three to four months for service, ie to remove sediment.

For all expansion turbines it is possible to determine the minimum inlet temperature at which there is still no condensation in the expansion turbine based on the water content of the exhaust gas. If the exhaust gas has a temperature lower than this minimum inlet temperature when entering the expansion turbine, condensation occurs.

On the other hand, if the inlet temperature of the exhaust gas rises above 175 ° C when entering the expansion turbine, the outlet temperature of the exhaust gas increases above 75 ° C. Since the exhaust gas enters the low pressure gas accumulator such that it has a uniform amount and calorific value, in this case the temperature of the exhaust gas must be reduced before entering the low pressure gas accumulator by direct or indirect cooling. When entering the low pressure gas accumulator, the exhaust gas should therefore not exceed the maximum exhaust gas temperature.

However, the use of an exhaust gas cooler for this purpose has the following disadvantages.

Capital costs for chillers, pumps, pipelines, water tanks, recooling,

-Power consumption and possibly water consumption for pumps and recooling,

-Direct contact with the exhaust gas and cooling water can lead to the introduction of harmful substances contained within it into the atmosphere.

-Agglomerated precipitate in the case of indirect coolers.

It is therefore an object of the present invention to at least avoid the cooling of the exhaust gas below the condensation temperature when leaving the expansion turbine or to avoid the use of the exhaust gas cooler in continuous operation for introduction of the exhaust gas into the low pressure gas accumulator.

The object is set such that when entering the expansion turbine the inlet temperature of the process gas is not lowered below the minimum inlet temperature at which condensation occurs in the expansion turbine, and / or the process gas causes the expansion turbine to enter the low pressure gas accumulator. Specifically, the following means ensure that the leaving process gas does not fall below the maximum allowable inlet temperature for this accumulator:

Adjusting the process gas temperature by adjusting the waste heat recovery plant, in particular the waste heat steam generator plant, which flows before the process gas enters the expansion turbine,

Controlling the process gas temperature by controlling the amount of process gas that is bypassed uncooled by the waste heat recovery plant, in particular the waste heat steam generator plant,

Mixing the compressed compressed further process gas with the process gas before the expansion turbine,

-Spraying water into the process gas (by which the dew point temperature can be shifted),

Mixing cold residual gas with process gas from the plant for CO ₂ removal after the expansion turbine

It is achieved by the method according to claim 1, which is cooled by one or more of.

Thus, there are three variants of the present invention,

플랜트의 시작에서 언급된 예에서, 이는 본 발명에 따른 조절에 의해, 프로세스 가스의 입구 온도가 146.5℃ 미만으로 저하되어서는 안된다는 것을 의미한다. 그러나, 이 수단의 결과로서, 팽창 터빈 이후의 프로세스 가스는 저압 가스 어큐뮬레이터에 대해 너무 고온일 수 있다.
A) When entering the expansion turbine, the inlet temperature of the process gas is set not to drop below the minimum inlet temperature at which condensation occurs in the expansion turbine. Thus, the process gas is cooled by the waste heat recovery plant only to the extent that it is not cooled or generally does not condense any component of the process gas in the expansion turbine. The waste heat recovery plant uses heat of hot process gas (approximately 350-450 ° C.) for steam generation to heat additional process gas or some other heat transfer medium (eg nitrogen or thermal oil) in either case. To this end, it is present as part of the pig iron manufacturing plant. COREX

In the example mentioned at the start of the plant, this means that, by the control according to the invention, the inlet temperature of the process gas should not be lowered below 146.5 ° C. As a result of this means, however, the process gas after the expansion turbine may be too hot for the low pressure gas accumulator.

플랜트의 시작에서 언급된 예에서, 이 수단은 팽창 터빈에 진입할 때에 프로세스 가스의 입구 온도가 단지 175℃ 미만으로 조절되는 것을 의미한다. 또는 팽창 터빈에 진입할 때에 프로세스 가스의 입구 온도는 조절되지 않고, 팽창 터빈을 떠나는 프로세스 가스는 75℃ 미만으로 냉각된다.
B) When the process gas enters the low pressure gas accumulator, the process gas leaving the expansion turbine is cooled to such an extent that the maximum allowable exhaust gas temperature for this accumulator does not exceed. In this case, condensation in the expansion turbine may be acceptable. The process gas is in this case pre-cooled before the expansion turbine, for example by cooling the gas in a waste heat recovery plant and / or by spraying water before the expansion turbine, or by spraying water after the expansion turbine and / or After the expansion turbine it is cooled by mixing cold residual gas from the plant for CO ₂ removal. In the case of cooling before the expansion turbine, condensation can then take place in the expansion turbine. COREX

In the example mentioned at the start of the plant, this means that the inlet temperature of the process gas is only adjusted below 175 ° C when entering the expansion turbine. Alternatively, when entering the expansion turbine, the inlet temperature of the process gas is not regulated, and the process gas leaving the expansion turbine is cooled below 75 ° C.

플랜트의 시작시에 언급된 예에서, 이는 예를 들어 대략 150℃ 내지 175℃의 범위의 값으로 조절되는 팽창 터빈에 진입할 때에 프로세스 가스 온도의 입구 온도에 의해 실현될 수 있다. 그러나, 또한 본 발명의 이 제 3 방법의 경우에도, 폐가스는 부가적으로 CO₂ 제거를 위한 플랜트로부터 차가운 잔류 가스 내에 혼합함으로써 및/또는 물을 분사함으로써 팽창 터빈 이후에 냉각될 수 있다.
C) The maximum allowable process gas for this accumulator when entering the low pressure gas accumulator at the same time, so that the inlet temperature of the process gas when entering the expansion turbine does not drop below the minimum inlet temperature at which condensation occurs in the expansion turbine. It is set to ensure that the exhaust gas temperature does not exceed. In the case of this means, condensation in the expansion turbine is avoided and a sufficiently low process gas temperature is ensured at the inlet into the low pressure gas accumulator. This may occur only as a result of the means prior to the expansion turbine, ie only as a result of the corresponding adjustment of the waste heat recovery plant, for example by the inclusion of a process gas which will possibly bypass it in an uncooled state. However, it is also possible that additionally cooled additional process gases are introduced or water is injected. COREX

In the example mentioned at the start of the plant, this can be realized by the inlet temperature of the process gas temperature, for example, when entering an expansion turbine which is adjusted to a value in the range of approximately 150 ° C to 175 ° C. However, also for this third method of the invention, the waste gas can additionally be cooled after the expansion turbine by mixing in cold residual gas and / or by spraying water from the plant for CO ₂ removal.

It is generally noted that upon injection of water into the process gas that occurs before the expansion turbine, in either case the condensation temperature or dew point temperature increases as a result, so that the minimum inlet temperature at which condensation occurs in the expansion turbine also increases. do.

The waste heat recovery plant need not be formed as a waste heat steam generator plant. Other heat exchangers may also be used instead. For example, one or more gas-gas heat exchangers can be used to heat additional process gases, for example in a pig iron manufacturing plant. Or other heat transfer medium, such as nitrogen or thermal oil, may also be heated to be used indirectly for heating other media. It goes without saying that a combination of different waste heat recovery plants is also possible.

Waste gases that have been previously removed from the pig manufacturing plant and not returned back to the pig manufacturing plant after the expansion turbine are generally used as process gas to be passed through the expansion turbine. It is called "exhaust gas" because it is actually clearly discharged from the pig iron manufacturing plant. The pig iron manufacturing plant here is not only a blast furnace or a melt gasifier and a reducing furnace but also a filter system (hot gas filter, bag filter, cyclone) and any waste heat boiler for cooling exhaust gases and also any plant for removal of CO ₂ . Include.

This process gas or exhaust gas may thus comprise the top gas from the blast furnace, in particular from the oxygen blast furnace.

However, waste gases from melt reduction plants, in particular

Waste gas from the melt gasifier,

Waste gas from one or more reduction reactors,

It may also comprise waste gases from one or more fixed bed reactors, in particular for preheating and / or reducing iron oxide and / or briquettes.

프로세스의 경우에 용융 가스화로 및 적어도 하나의 고정층 반응기는 철 운반체의 환원을 위해 사용되고, FINEX

프로세스의 경우에 하나가 다른 하나의 후방에 접속되고 유동상 반응기로서 형성되어 있는 용융 가스화로 및 다수의 환원 반응기가 사용된다.
Thus, for example, COREX

In the case of a process, a melt gasification furnace and at least one fixed bed reactor are used for the reduction of the iron carrier, FINEX

In the case of a process, a melt gasification furnace and a plurality of reduction reactors are used in which one is connected behind the other and formed as a fluidized bed reactor.

It goes without saying that the process gas or exhaust gas from the melt reduction plant used for the present invention can be supplied from multiple sources of the melt reduction plant. Partial streams from individual parts of the plant (melt gasification, reduction reactor, fixed bed reactor) will generally vary over time.

The process gases mentioned from pig iron manufacturing plants (blast furnaces or melt reduction furnaces) can additionally also be removed from the plant in some other way, so-called exhaust gases and cooled compressed additions before expansion turbines for cooling purposes. Can be mixed as, for example, if the exhaust gas or process gas has been cooled too much by the waste heat recovery plant and these gas streams have been prewashed to a high temperature condition, these process gases can be mixed for heating purposes. It is also possible.

It is suitable to use a cooled process gas which occurs in any case in the pig iron manufacturing plant during pig iron manufacturing, such as, for example, a washed cooled reducing gas (residue gas) from a molten gasifier that has not been passed to the reduction reactor. Do.

In order to avoid condensation in the expansion turbine, it may be provided that the inlet temperature of the process gas when entering the expansion turbine is not below the minimum inlet temperature of approximately 145 ° C.

It is best to set the inlet temperature of the process gas to a value in the range of 150 to 175 ° C when entering the expansion turbine, in order to prevent condensation of the exhaust gas or the process gas and excessive inlet temperature when entering the low pressure gas accumulator. Is provided. This creates an outlet temperature of the process gas when leaving the expansion turbine in the range of 55 to 75 ° C., and further cooling after the expansion turbine is then no longer needed.

However, the exhaust gas or process gas may additionally or alternatively also be cooled before or after the expansion turbine to such an extent that the maximum inlet temperature when entering the low pressure gas accumulator of approximately 80 ° C. is not exceeded.

In order to protect the expansion turbine from abrasion and soiling, it may be provided that at least a portion of the process gas is dry dust removed before the expansion turbine. Dry dust removal generally occurs in any case within the pig iron manufacturing plant, and there is no need for a dedicated dry dust removal facility to be subsequently installed for the expansion turbine. Dry dust removal typically takes place by a bag filter arranged downstream of the waste heat recovery plant or by a ceramic hot gas filter arranged upstream of the waste heat recovery plant. In addition, hot gas cyclones or so-called "dust catchers" (dust separators) can also be used, which serve to remove coarse dust and plants for the removal of fine dust (bag filters, hot gases). Upstream side of the filter). Dry dust removal has the advantage over a wet process where too much energy is thereby not extracted from the process gas, and then all are intended to be used in the expansion turbine.

A corresponding apparatus for carrying out the process according to the invention is characterized in that the pig iron manufacturing plant is connected to at least a first process gas line for introducing process gas into the expansion turbine, the expansion turbine being connected to a low pressure gas accumulator for process gas in a second process. It can be configured to be connected by a gas line, one of the following devices, namely

A first heat control plant and a waste heat steam generator plant arranged before an expansion turbine in a waste heat recovery plant, in particular a pig iron manufacturing plant, the first control device for the waste heat recovery plant having a function for regulating the process gas temperature Regulating unit and waste heat recovery plant,

A second regulating device and a bypass line, the second regulating device having a function for adjusting the amount of process gas to be bypassed by the waste heat recovery plant, in particular the waste heat steam generator plant, uncooled by the bypass line. Second adjusting device and bypass line,

A third regulating device in which the amount of compressed further process gas cooled from the pig iron manufacturing plant that is passed into the first process gas line is controlled,

A fourth adjusting device in which the amount of water which can be injected into the first or second process gas line by the spraying device is controlled,

There is additionally also provided a fifth regulating device in which the amount of cold residual gas is regulated from the plant for the removal of CO ₂ mixed to form the process gas by the residual gas line into the second process gas line.

If there are a number of these five mentioned control devices, they are connected to one of the central control facilities or control devices, for example the first device, and undertake the calculation of the control and setpoint values and the manipulated values of the other control devices. do.

When the exhaust gas from the blast furnace is passed into the expansion turbine, at least one line is provided from which the top gas from the blast furnace, in particular from the oxygen blast furnace with the return gas return, can be passed into the first process gas line.

When the exhaust gas from the melt reduction plant is passed into the expansion turbine, at least one line is provided through which waste gas from the melt reduction plant can be passed into the first process gas line. In this case, at least one of these lines is the following device, i.e.

-Melt gasification furnace,

One or more reduction reactors,

Fixed bed reactors, in particular for preheating and / or reducing iron oxide and / or briquettes

Is connected to at least one of.

The plant for dry dust removal of the process gas may be arranged before the expansion turbine. This serves to protect the expansion turbine from contamination and polishing.

The invention is explained in more detail below on the basis of the schematic diagram provided by way of example.

플랜트를 도시하고 있는 도면이며,
도 2는 먼지 제거를 위한 세라믹 필터 및 하류측 팽창 터빈을 갖는 COREX

플랜트를 도시하고 있는 도면이며,
도 3은 먼지 제거를 위한 백 필터 및 하류측 팽창 터빈을 갖는 FINEX

플랜트를 도시하고 있는 도면이며,
도 4는 먼지 제거를 위한 백 필터 및 하류측 팽창 터빈을 갖는 FINEX

플랜트를 도시하고 있는 도면이며,
도 5는 먼지 제거를 위한 백 필터 및 하류측 팽창 터빈을 갖는 산소 고로를 도시하고 있는 도면이며,
도 6은 먼지 제거를 위한 세라믹 필터 및 하류측 팽창 터빈을 갖는 산소 고로를 도시하고 있는 도면이다.1 shows a COREX with a bag filter and downstream expansion turbine for dust removal

It is a drawing showing a plant,
2 is a COREX with ceramic filter and downstream expansion turbine for dust removal;

It is a drawing showing a plant,
3 shows a FINEX with a bag filter and downstream expansion turbine for dust removal;

It is a drawing showing a plant,
4 shows a FINEX with a bag filter and downstream expansion turbine for dust removal;

It is a drawing showing a plant,
FIG. 5 shows an oxygen blast furnace having a bag filter and a downstream expansion turbine for dust removal;
FIG. 6 shows an oxygen blast furnace with a ceramic filter and a downstream expansion turbine for dust removal.

플랜트가 도시되어 있다. 이 예에서, 이는 고정층 반응기로서 형성되고 괴광, 펠릿, 소결물 및 첨가제(도면 부호 18 참조)로 장입되는 환원로(17)를 갖는다.
In Figure 1, COREX

The plant is shown. In this example, it has a reduction furnace 17 which is formed as a fixed bed reactor and charged with lumps, pellets, sinters and additives (see reference numeral 18).

The reducing gas 19 is guided countercurrent to the lump or the like 18. This reducing gas is introduced into the lower region of the reducing furnace 17 and leaves the upper side as the top gas 22. The heat of the top gas 22 from the reduction furnace 17 is used in the waste heat boiler 21 for steam generation, whereby the low pressure steam produced is shown in the plant 14-here for the chemical adsorption of CO ₂ . Not present-can be supplied to a stripper of. Prior to entering the waste heat boiler 21, the top gas 22 may be coarse dust removed in the dust separator or cyclone 23. The dust 24 separated from the cyclone 23 can be returned into the melt gasifier 48.

The top gas leaving the waste heat boiler 21 is further washed in the bag filter 30 and passed to the expansion turbine 34 as exhaust gas 12.

The reducing gas 19 for the reduction furnace 17 is produced in the melt gasifier 48, into coal and possibly powder form in the form of lump coal 49 on the one hand. Coal is supplied and on the other hand iron ore pre-reduced in the reduction furnace 17 is added. Fine ore 47 too fine for the reduction furnace 17 can also be introduced with the lump coal 49.

The coal in the melt gasifier 48 is gasified to produce a gas mixture consisting primarily of CO and H ₂ , discharged as a top gas (generator gas) 54, where a separator 59 is formed as a hot gas cyclone. If the dust and the spectra in it are washed away, the partial stream is passed to the reduction furnace 17 as reducing gas 19. The separated dust and separated spectrometer 25 here are returned into the melt gasifier 48.

The hot metal and slag melted in the melt gasifier 48 are discharged (see arrow 58).

The top gas 54 discharged from the melt gasifier 48 separates the entrained dust and returns the dust 25 into the melt gasifier 48-possibly via a pulverized fuel combustor. To be first passed into separator 59.

플랜트로부터 잔여 가스(27)로서 제거되고, - 본 발명에 따르면 - 팽창 터빈(34) 이전에 배기 가스(12)에 공급된다. 대안적으로 또는 추가로, 잔여 가스(27)의 부분은 팽창 터빈(34) 이후에 배기 가스(12)와 혼합되어 상기 가스를 냉각할 수 있다.
Part of the coarse dust washed top gas 54 is further washed by the wet scrubber 26 and the COREX

It is removed from the plant as residual gas 27 and supplied to the exhaust gas 12 before the expansion turbine 34-according to the invention. Alternatively or in addition, a portion of residual gas 27 may be mixed with exhaust gas 12 after expansion turbine 34 to cool the gas.

프로세스를 위해 여전히 사용될 수 있게 하고, 다른 한편으로는 약 1050℃로부터 700 내지 870℃로 고온 노정 가스 또는 발생기 가스(54)의 요구된 냉각이 보장되는 것을 허용한다.
A portion of the cleaned top gas or generator gas 54 is passed after cooling through the wet scrubber 26 to the gas compressor 63 for cooling, followed by the top gas or generator gas after the melt gasifier 48 for cooling. 54 is returned as the cooling gas 28. This return indicates that the reducing component contained therein is COREX

Still available for the process and on the other hand allow the required cooling of the hot top gas or generator gas 54 from about 1050 ° C to 700 to 870 ° C.

Between the cyclone 23 and the waste heat boiler 21, water is injected into the top gas 22 by the first injection device 29 to cool it. After the waste heat boiler 21, the top gas 22 is passed into the bag filter where fine dust is separated. After the bag filter, the first process gas line 31 for the exhaust gas 12 starts and ends in the expansion turbine 34. The second process gas line 32 begins in the expansion turbine 34 and ends in the exhaust gas tank 13 formed as a low pressure gas accumulator.

A line for the residual gas 27 is first opened into the first process gas line, after which a second injection device 33 is provided for further cooling the exhaust gas 12.

By-pass line 36 allows top gas 22 to be passed by waste heat boiler 21 in an uncooled state.

In the first regulating device 45, the process occurring in the waste heat boiler 21 is regulated, but it is also connected to another regulating device according to the invention as indicated by the dashed line,

A second regulating device in the form of a controllable valve 46, whereby the bypass line 36 is fully or partially open or shut off,

A third regulating device in the form of a controllable valve 57, for a line for the residual gas 27, and

It is here connected to a fourth control device in the form of a controllable valve 56 for the second injection device 33.

In addition, the first regulating device 45 includes a first temperature sensor 67 which measures the temperature of the exhaust gas 12 immediately before entering the expansion turbine 34, and the exhaust gas (i.e. immediately after leaving the expansion turbine 34). A second temperature sensor 68 measuring the temperature of 12) and a third temperature sensor 69 measuring the difference between the measured values of the first and second temperature sensors.

Based on the measured temperature value, the set point value is then determined and set by the assistance of the regulating device.

Excess exhaust gas is conveyed to the residual gas combustor plant 72 via the first line 70 before the expansion turbine 34 and through the second line 71 after the expansion turbine 34 to be burned there. Can be.

After the pressure measurement by the pressure sensor 73, a portion of the exhaust gas 12 can be passed by the expansion turbine 34 by the bypass line 74 for the turbine. This is not only particularly required for running up and running down of expansion turbines, but can also be used during normal operation to adjust the fraction of gas.

For the sake of safety, the exhaust gas cooler 75, in which the gas mixture of the exhaust gas 12 after the expansion turbine 34 and the residual gas 27 introduced after the expansion turbine 34, is completely or partially cooled, nevertheless Nevertheless it may be arranged after the expansion turbine 34. The portion to be cooled is taken from the second process gas line 32, passed through the exhaust gas cooler 75, and returned to the second process gas line 32. Cold water 76 is used for cooling. If the adjustment according to the invention fails, it can be ensured by the exhaust gas cooler 75 that the exhaust gas 12 does not enter the exhaust gas tank 13 at too high a temperature.

플랜트가 도시되어 있지만, 이는 먼지 제거를 위해 사용되는 필터에 의해 도 1의 것과 상이하다.
As in Figure 1, Figure 2 shows COREX

Although the plant is shown, this differs from that of FIG. 1 by the filter used for dust removal.

Instead of the cyclone 23 for the top gas from FIG. 1, a hot gas filter 11 with a ceramic filter element is used. In hot gas filters, hot gas filter elements are used, mainly in the form of porous candles of ceramic, fiber ceramic or sintered metal. Dust accumulated on the filter candle can be washed out of the filter candle by a backwashing device, which is typically operated with nitrogen (N ₂ ).

Separated dust in the hot gas filter 11 may alternatively be returned to the melt gasifier 48.

A further variant is that the cyclone, more particularly the hot gas cyclone, is arranged before the hot gas filter 11. This further allows for dust content of the top gas 22 to be reduced.

플랜트가 도 1 및 도 2의 COREX

플랜트 대신에 사용된다.
In Figure 3, FINEX

Plant is COREX of FIGS. 1 and 2

It is used instead of the plant.

The exhaust gas 12 is supplied to the expansion turbine 34 and thereafter buffered again in the exhaust gas 13 formed as a low pressure gas accumulator. This gas can then be supplied as fuel to the raw material drying plant or the power plant (see reference numeral 35).

플랜트는 이 예에서 유동상 반응기로서 형성되고 분광으로 장입되는 4개의 환원 반응기(37 내지 40)를 갖는다. 분광 및 첨가제(41)는 광석 건조 시설(42)로 공급되고 거기로부터 먼저 제 4 반응기(37)로 공급되고, 이들은 이어서 제 3 환원 반응기(38), 제 2 환원 반응기(39) 및 마지막으로 제 1 환원 반응기(40) 내로 통과된다. 그러나, 4개의 유동상 반응기(37 내지 40) 대신에, 단지 3개만이 또한 존재할 수 있다.
FINEX

The plant has four reduction reactors 37 to 40 which in this example are formed as fluidized bed reactors and are loaded spectroscopically. Spectroscopy and additives 41 are fed to the ore drying plant 42 and from there first to the fourth reactor 37, which in turn is the third reduction reactor 38, the second reduction reactor 39 and finally the third agent. 1 is passed into the reduction reactor 40. However, instead of four fluidized bed reactors 37 to 40, only three may also be present.

The reducing gas 43 is guided countercurrent to the spectroscopy. This gas is introduced at the bottom of the first reduction reactor 40 and leaves at its upper side. Before entering the second reduction reactor 39 from below, this reducing gas can also be similarly heated with oxygen (O ₂ ) between the second reduction reactor 39 and the third reduction reactor 38. The heat of the waste gas 44 from the reduction reactors 37 to 40 is used in the waste heat boiler 21 for steam generation, whereby the low pressure steam produced is sent to the stripper of the plant 14 for chemical adsorption of CO ₂ . Can be supplied.

프로세스에서 재차 사용되도록 의도된다. 이 목적으로, 이는 냉수(78)에 의해 가스 냉각기(77) 내에서 냉각되고, 복귀 가스 압축기(80) 내에서 압축되고, 하류측 냉각기(81) 내에서 재차 냉각되고, 이어서 예를 들어 흡착(예를 들어, 압력 변동 플랜트 또는 진공 압력 변동 플랜트) 또는 화학적 흡착에 의해 CO₂의 제거를 위한 플랜트(14)에 공급된다.
The waste gas 44 leaving the fourth reduction reactor 37 is washed in the bag filter 30 after the waste heat boiler 21. A partial stream of waste gas leaving the bag filter 30 is supplied to the expansion turbine 34 as exhaust gas 12, and a further partial stream is FINEX as return gas 79.

It is intended to be used again in the process. For this purpose, it is cooled in the gas cooler 77 by cold water 78, compressed in the return gas compressor 80, cooled again in the downstream cooler 81, and then, for example, by adsorption ( Pressure fluctuation plant or vacuum pressure fluctuation plant) or by chemical adsorption to the plant 14 for the removal of CO ₂ .

If the release of CO ₂ to the atmosphere in the production of pig iron should be reduced, it is separated from the waste gas from the production of pig iron and stored in combined form (CO ₂ capture and sequestration (CCS)).

The residual gas stream 82 after the chemisorption 14 mainly contains CO ₂ , and a portion of the residual gas 82 is exhausted through the residual gas line 84 which is open into the second process gas line 32. It may be passed into the exhaust gas 12 prior to entering the gas tank. The corresponding fifth adjustment device 20 is shown in FIG. 3 for this purpose.

The reducing gas 43 is produced in the melt gasifier 48 in FIG. 3, into which the coal in the form of lump coal 49 and possibly coal in powder form 50 are fed. Coal in powder form, together with oxygen (O ₂ ), on the other hand, is pre-reduced in reduction reactors 37 to 40 and briquettes (HCI :) at high temperature in an iron briquetting facility 51. Iron ore molded from hot pressed iron) is added. The briquettes in this case are passed by a transfer plant 52 into a storage tank 53 formed as a fixed bed reactor, where the briquettes are preheated and reduced to a coarse washed generator gas 54, possibly from a melt gasifier 48. do. Here, cold briquettes 65 may also be added. Thereafter, briquettes or oxides are charged from above into the melt gasifier 48. Low reducing iron (LRI) may likewise be discharged from the briquetting facility 51.

The coal in the melt gasifier 48 is gasified to produce a gas mixture consisting primarily of CO and H ₂ , discharged as reducing gas (generator gas) 54, and the partial stream as reducing gas 43 as a reduction reactor ( 37 to 40).

The molten hot metal and slag in the melt gasifier 48 are discharged (see arrow 58).

The top gas 54 discharged from the melt gasifier 48 is first passed into the separator 59 to separate the entrained dust and return the dust into the melt gasifier 48 via the differential fuel combustor.

The part of the coarse dust-washed top gas is further washed by the wet scrubber 60 and specifically fed to the plant 14 as residual gas 61 for chemical absorption of CO ₂ before the return gas compressor 80. do.

프로세스를 위해 사용될 수 있게 하고, 다른 한편으로는 고온 발생기 가스(54)의 요구 냉각이 보장될 수 있게 한다.
A further portion of the washed generator gas 54 is likewise further washed in the wet scrubber 62 to cool the gas, passed for cooling to the gas compressor 63 and then taken from the plant 14 and the CO After mixing with return gas 79 where ₂ has been removed, it is returned to generator gas 54 after melt gasifier 48 for cooling. This return of the gas 79 from which CO ₂ has been removed indicates that the reducing component contained therein is still FINEX

It can be used for the process and on the other hand the required cooling of the high temperature generator gas 54 can be ensured.

The top gas 55 leaving the storage plant 53 where briquettes or iron oxides are dedusted from the melt gasifier 48 and heated and reduced with the cooled generator gas 54 is washed in the wet scrubber 66 and then likewise. It may be fed to the plant 14 for the removal of CO ₂ .

In the case of a chemical adsorption plant for CO ₂ removal, the stripper of the plant 14 may be fed low pressure steam from the waste heat boiler 21. Preferably, waste heat from the iron manufacturing process should be used for this case because of the short distance between the waste heat boiler and the plant 14 for the chemical absorption of CO ₂ .

The condensate of the stripper can in this example be supplied to the steam circuit of the waste heat boiler 21.

The exhaust gas 12 here consists solely of the waste gas 44 of the reduction reactors 37 to 40.

All regulating devices (first device 45, second device 46, fourth device 56 and fifth device 20) present in the present exemplary embodiment are connected to each other and their manipulated variables. Is specified at the center.

The mode of operation of the second injector 33, optional exhaust gas cooler 75, residual gas combustor plant 72, temperature sensors 67 to 69, pressure sensor 73 and bypass line 74 is shown in FIG. 1. As described in.

프로세스에서 재차 사용되도록 의도된다.
The plant of FIG. 4 essentially corresponds to that of FIG. 3, but the waste gas 44 leaving the fourth reduction reactor 37 in FIG. 4 is washed in the hot gas filter 11 before the waste heat boiler 21. The partial stream of waste gas leaving the waste heat boiler 21 is then supplied to the expansion turbine 34 as exhaust gas 12, and the further partial stream is FINEX as return gas 79.

It is intended to be used again in the process.

In Fig. 5, the present invention is expressed based on an oxygen blast furnace. Here, iron ore and coke (not shown) from the sintering plant 2 are supplied into the blast furnace 1 from above by a charging device. Oxygen containing gas 3 having an oxygen content of more than 80% is introduced into a bustle pipe 4, and similarly coal is introduced in powder form 50. In the reducing gas furnace 6, the reducing gas 5 is heated with oxygen O ₂ and combustion air supplied for combustion. Together with cold or preheated oxygen (O ₂ ), the heated reducing gas (5) is introduced into the blast furnace (1). The slag 7 and pig iron 8 are discharged from the blast furnace 1 at the bottom. At the upper side of the blast furnace 1, the top gas or blast furnace gas 9 is removed and prewashed in the dust separator or cyclone 10. The top gas or blast furnace gas 9 cleaned in this way is still so hot that its energy can be used in a meaningful way in the waste heat boiler 21 for steam generation. As in the case of the waste heat boiler 21 of the other figures, here the circuit on the left side represents the steam circuit, and the circuit on the right side functions for heating and evaporating the condensate. In order to cool the top gas 9 before the waste heat boiler, a first injection device 29 for water is again provided. By-pass line 36, top gas 9 can be guided around waste heat boiler 21 in an uncooled state again. After the waste heat boiler 21, the top gas 9 enters the bag filter 30 (but a wet scrubber may also be arranged at this point instead) and is further washed, so that fine dust is also separated and removed (See the arrow at the bottom of the bag filter 30).

Washed and possibly cooled top gas 9 can, on the one hand, be removed directly from the blast furnace system as exhaust gas 12 and then fed to the expansion turbine 34 and subsequently to the exhaust gas tank 13. On the other hand, this gas can be supplied to the plant 14 for CO ₂ removal, and the top gas or blast furnace gas 9 to be washed and returned is pre-cooled in the gas cooler 77, which is cold water And cooled to approximately 2 to 6 bar _g by the compressor 15 and to approximately 30 to 60 ° C. in the aftercooler 16. Only the top gas 9 to be returned next is introduced into the plant 14 for CO ₂ removal. The operating mode of this plant has already been described with reference to FIG. 3. Further provided in FIG. 4 is that the return gas 9 to be returned is merely a gas cooler 77, only a plant 14 or gas cooler 77 and a plant 14 as a reducing gas furnace 6 as fuel gas. The line that passes through, represented by the dashed line.

The product gas from which the CO ₂ has been washed is returned to the blast furnace 1 as reducing gas 5 directly and / or after heating in the reducing gas furnace 6. The CO ₂ -rich residual gas 82 is discharged directly to the atmosphere and / or subsequent CO ₂ storage devices (such as EOR-enhanced oil recovery-, EGR-enhanced gas), as shown in FIG. Can be actually supplied to the CO ₂ compression plant and / or but also used as a substitute for N ₂ in iron production, the residual gas stream consisting mainly of CO ₂ and thus the device, the barrier seal and Can be used to charge selected flush-gas and cold-gas consumers.

However, part of the residual gas 82 may also be supplied as fuel gas to the reducing gas furnace 6. Finally, a portion of the residual gas 82 passes through the exhaust gas 12 prior to entering the exhaust gas tank for cooling through a residual gas line 84 that is open into the second process gas line 32. Can be. A corresponding fifth adjusting device 20 for this purpose is shown in FIG. 4.

All the regulating devices (first device 45, second device 46, fourth device 56 and fifth device 20) present in this exemplary embodiment are connected to each other and their manipulated variables. Is specified at the center.

The mode of operation of the second injector 33, optional exhaust gas cooler 75, residual gas combustor plant 72, temperature sensors 67 to 69, pressure sensor 73 and bypass line 74 is shown in FIG. 1. As described in.

The plant from FIG. 6 differs from the plant of FIG. 5 only by the type of cleaning of the top gas 9. Specifically, in FIG. 6 the top gas 9 is further washed in the hot gas filter 11 after the dust separator or cyclone 10, so that fine dust can also be separated and removed (hot gas filter 11). Arrow at the bottom of)]. The top gas or blast furnace gas 9 cleaned in this way is then only passed into the waste heat boiler 21.

The exhaust gas 12 from the exhaust gas tank 13 can be passed as fuel to the combined heat and power plant or steam plant-irrespective of the embodiment of the invention.

1: blast furnace 2: sintering plant
3: oxygen-containing gas 4: annular pipe
5: reducing gas 6: reducing gas
7: slag 8: pig iron
9: top gas or blast furnace gas 10: dust separator or cyclone
11: high temperature gas filter 12: exhaust gas
13: Exhaust gas tank 14: Plant for chemical adsorption of CO ₂
15: compressor 16: aftercooler
17: reduction furnace 18: mass steel, pellets, sintering and additives
19: reducing gas 20: fifth regulator (valve)
21: waste heat boiler 22: top gas
23: cyclone 24: dust
25: dust and spectroscopy 26: wet scrubber
27: residual gas 28: cooling gas
29: first injection device 30: bag filter
31: first process gas line 32: second process gas line
33: second injector 34: expansion turbine
35: raw material drying plant (coal, coal or ore drying) or power plant
36: bypass line 37: fourth reduction reactor
38: third reduction reactor 39: second reduction reactor
40: first reduction reactor 41: spectroscopy and additives
42: iron ore drying plant 43: reducing gas
44: waste heat 45: first adjusting device
46: second regulating device (valve) 47: spectroscopy
48: melt gasification furnace 49: lump coal
50: coal in powder form 51: briquetting plant
52: conveying plant 53: storage tank
54: top gas or generator gas 55: top gas
56: fourth adjusting device (valve) 57: third related device (valve)
58: hot metal and slag 59: spectroscopy separator
60: wet scrubber 61: residual gas
62: wet scrubber 63: gas compressor
64: CO ₂ removed gas 65: cold briquette
66: wet scrubber 67: first temperature sensor
68: second temperature sensor 69: third temperature sensor
70: first line 71: second line
72: residual gas combustor plant 73: pressure sensor
74: bypass line 75: exhaust gas cooler
76: cold water 77: gas cooler
78: cold water 79: return gas
80: return gas compressor 81: cooler
82: residual gas 83: combustion gas
84: residual gas line

Claims (14)

In a method for regulating the temperature of a process gas 12 from a pig iron manufacturing plant for use in an expansion turbine 34,
When entering the expansion turbine 34 the inlet temperature of the process gas 12 is set so as not to drop below the minimum inlet temperature at which condensation occurs in the expansion turbine, and / or the process gas 12 is at low pressure. Specifically, the process means leaving the expansion turbine upon entering the gas accumulator 13 does not fall below the maximum allowable inlet temperature for the accumulator:
Adjusting the process gas temperature by adjusting the waste heat recovery plant, in particular the waste heat steam generator plant 21, which flows before the process gas 12 enters the expansion turbine 34;
Adjusting the process gas temperature by controlling the amount of process gas that is bypassed uncooled by the waste heat recovery plant, in particular waste heat steam generator plant 21,
Mixing the further compressed compressed process gas 27 before the expansion turbine 34 with the process gas 12,
Spraying water (29, 33) into the process gas (12),
Mixing the cold residual gas 82 with the process gas 12 from the plant 14 for CO ₂ removal after the expansion turbine 34.
Characterized by being cooled by one or more of
Method for regulating the temperature of process gas from pig iron manufacturing plant.
The method of claim 1,
Characterized in that a waste gas which is previously removed from the pig manufacturing plant and not returned to the pig manufacturing plant after the expansion turbine 34 is used as the process gas 12,
Method for regulating the temperature of process gas from pig iron manufacturing plant.
3. The method according to claim 1 or 2,
Characterized in that, from the blast furnace, in particular the top gas 9 from the oxygen blast furnace 1 is used as the process gas, possibly as an additional process gas,
Method for regulating the temperature of process gas from pig iron manufacturing plant.
3. The method according to claim 1 or 2,
Characterized in that waste gases 22, 27, 44 from melt reduction furnaces 17, 37-40, 48 are used as process gas, possibly as further process gas,
Method for regulating the temperature of process gas from pig iron manufacturing plant.
The method of claim 4, wherein
The following waste gases, namely
Waste gas 27 from the melt gasifier 48,
Waste gas 44 from at least one reduction furnace 37 to 40,
Waste gas 22 from at least one fixed bed reduction furnace 17, in particular for preheating and / or reducing iron oxide and / or briquettes
Characterized in that at least one of is used,
Method for regulating the temperature of process gas from pig iron manufacturing plant.
6. The method according to any one of claims 1 to 5,
Characterized in that the inlet temperature of the process gas 12 when entering the expansion turbine 34 does not become below the minimum inlet temperature of approximately 145 ° C,
Method for regulating the temperature of process gas from pig iron manufacturing plant.
The method according to claim 6,
Characterized in that the inlet temperature of the process gas 12 when entering the expansion turbine 34 is set to a value in the range of 150 to 175 ℃,
Method for regulating the temperature of process gas from pig iron manufacturing plant.
The method according to any one of claims 1 to 7,
The process gas 12 is characterized in that it is cooled before or after the expansion turbine 34 to such an extent that the maximum inlet temperature when entering the low pressure gas accumulator 13 at approximately 80 ° C. is not exceeded.
Method for regulating the temperature of process gas from pig iron manufacturing plant.
The method according to any one of claims 1 to 8,
At least a portion of the process gas 12 is characterized in that dry dust is removed before the expansion turbine 34,
Method for regulating the temperature of process gas from pig iron manufacturing plant.
Apparatus for carrying out a method for regulating the temperature of a process gas from a pig iron manufacturing plant according to any one of claims 1 to 9,
The pig iron manufacturing plant is connected to at least a first process gas line 31 for introducing process gas 12 into expansion turbine 34, which is connected to a low pressure gas accumulator 13 for process gas. Connected by the second process gas line 32, one of the following devices, i.e.
A first regulating device 45 and a waste heat steam generator plant 21 arranged before the expansion turbine 34 in a waste heat recovery plant, in particular in a pig iron manufacturing plant, the first regulating device for the waste heat recovery plant 21. 45, a first regulating device 45 and a waste heat recovery plant, functioning to regulate the process gas temperature,
A second regulating device 46 and a bypass line 36, the second regulating device 46 being uncooled by the bypass line 36, in particular a waste heat recovery plant, in particular a waste heat steam generator plant 21. Second regulating device 46 and bypass line 36, which serve to regulate the amount of process gas bypassing
A third regulating device 57 for regulating the amount of compressed further process gas 27 cooled from the pig iron manufacturing plant that is passed into the first process gas line 31,
A fourth regulating device 56 for regulating the amount of water which can be injected into the first process gas line 31 or the second process gas line 32 by means of an injection device 33,
A fifth regulating device 20 in which the amount of cold residual gas is regulated from the plant for CO ₂ removal mixed by the residual gas line 84 to form the process gas 12 into the second process gas line 32. ) Is also additionally provided,
Apparatus for implementing a method for controlling the temperature of a process gas from a pig iron manufacturing plant.
11. The method of claim 10,
It is characterized in that at least one line is provided through which the top gas 9 from the blast furnace, in particular from the oxygen blast furnace 1 with the top gas return, can be passed into the first process gas line 31,
Apparatus for implementing a method for controlling the temperature of a process gas from a pig iron manufacturing plant.
11. The method of claim 10,
Characterized in that one or more lines are provided through which waste gases 22, 27, 44 from the melt reduction plant can be passed into the first process gas line 31,
Apparatus for implementing a method for controlling the temperature of a process gas from a pig iron manufacturing plant.
13. The method of claim 12,
At least one of the lines is a device,
Melt gasifier (48),
One or more reduction furnaces (37-40),
Fixed-bed reduction furnaces 17 especially for preheating and / or reducing iron oxide and / or briquettes
Characterized in that connected to at least one of,
Apparatus for implementing a method for controlling the temperature of a process gas from a pig iron manufacturing plant.
The method according to any one of claims 10 to 13,
The plant 11, 23, 30 for dry dust removal of the process gas 12 is characterized in that it is arranged before the expansion turbine 34,
Apparatus for implementing a method for controlling the temperature of a process gas from a pig iron manufacturing plant.

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