焦爐煤氣(簡稱COG ) 是煉焦過程中, 在產(chǎn)出焦炭和焦油產(chǎn)品的同時所得到的可燃氣體,是煉焦過程中最重要的副產(chǎn)品。COG主要由氫氣和甲烷構成，分別占56%和27%，并有少量一氧化碳、二氧化碳、氮氣、氧氣和其他烴類；其熱值約為4400大卡/方，天然氣熱值為8500大卡/方，焦爐煤氣熱值約為天然氣的一半。我國每年焦爐氣年產(chǎn)量超千億立方米，如此之大的產(chǎn)量，如果能夠得到充分合理的利用，所帶來的經(jīng)濟效益和環(huán)境效益都將是巨大的。因此，筆者探討了焦爐煤氣的各種利用途徑，并結合鋼鐵企業(yè)的實際情況,  分別對其進行了分析。

　　Coke oven gas (COG) is a combustible gas obtained during the coking process, which produces coke and tar products. It is the most important byproduct of the coking process. COG is mainly composed of hydrogen and methane, accounting for 56% and 27% respectively, with small amounts of carbon monoxide, carbon dioxide, nitrogen, oxygen, and other hydrocarbons; Its calorific value is about 4400 kcal/m3, natural gas calorific value is 8500 kcal/m3, and coke oven gas calorific value is about half of natural gas. China's annual production of coke oven gas exceeds 100 billion cubic meters. If such a large output can be fully and reasonably utilized, the economic and environmental benefits it brings will be enormous. Therefore, the author explored various utilization methods of coke oven gas and analyzed them separately based on the actual situation of steel enterprises.

　　焦爐煤氣的主要利用途徑

　　The main utilization methods of coke oven gas

　　1、加熱燃料焦爐煤氣的傳統(tǒng)利用方式是作為不同加熱設備的氣體燃料。與固體燃料相比較, 有使用便捷、可以管道輸送和傳熱效率高等優(yōu)點, 受到工業(yè)和民用的青睞。工業(yè)燃氣: 焦爐煤氣作為氣體燃料, 可用于焦爐加熱、軋鋼加熱爐、高爐熱風爐、燒結點火等。但隨著企業(yè)內(nèi)能量利用率的提高和替代燃料(如高爐煤氣) 的使用, 加熱所需要的焦爐煤氣量將不斷減少。民用燃氣: 焦化廠生產(chǎn)的焦爐煤氣經(jīng)過凈化后, 作為燃氣可供當?shù)鼐用袷褂谩５? 近幾年來隨著西氣東輸工程的實施, 沿線大中城市作為民用燃料的焦爐煤氣將逐漸被天然氣替代(例如北京居民用燃氣已全部采用天然氣)。所以,這部分焦爐煤氣的需求量也在逐漸減少。綜上所述, 雖然目前作為加熱燃料仍是焦爐煤氣的主要利用途徑之一, 但其焦爐煤氣的需求量正在逐漸下降。

　　1. The traditional way of using coke oven gas as heating fuel is as gas fuel for different heating equipment. Compared with solid fuels, it has the advantages of convenient use, pipeline transportation, and high heat transfer efficiency, and is favored by both industry and civilian use. Industrial gas: Coke oven gas, as a gas fuel, can be used for coke oven heating, steel rolling heating furnaces, blast furnace hot blast stoves, sintering ignition, etc. But with the improvement of energy utilization efficiency within enterprises and the use of alternative fuels such as blast furnace gas, the amount of coke oven gas required for heating will continue to decrease. Civilian gas: After purification, the coke oven gas produced by coking plants can be used as gas for local residents. However, in recent years, with the implementation of the West East Gas Pipeline Project, coke oven gas, which is used as a civilian fuel in large and medium-sized cities along the route, will gradually be replaced by natural gas (for example, natural gas has been used exclusively for residential gas in Beijing). So, the demand for coke oven gas in this part is gradually decreasing. In summary, although coke oven gas is still one of the main utilization methods as a heating fuel, its demand is gradually decreasing.

　　2、用于發(fā)電將焦爐煤氣用于發(fā)電，是近幾年來焦爐煤氣的主要利用途徑之一。我國焦爐煤氣發(fā)電一般有三種方式: 蒸氣發(fā)電、燃氣輪機發(fā)電和內(nèi)燃機發(fā)電。對于獨立焦化廠而言, 在利用焦爐煤氣發(fā)電時, 多采用的是燃氣內(nèi)燃機技術, 其設備投資較小且焦爐煤氣成本低, 所以經(jīng)濟效益顯著。而對于國內(nèi)大中型鋼鐵企業(yè)而言, 在利用焦爐煤氣發(fā)電時, 多采用的是燃氣-蒸氣聯(lián)合循環(huán)發(fā)電技術(CCPP), 普遍存在設備一次性投資大、維護及備件費用高、電價居高不下等問題。由此看來, 對于鋼鐵企業(yè)內(nèi)部的焦化廠發(fā)電并不是利用焦爐煤氣的最佳途徑。

　　2. The use of coke oven gas for power generation has been one of the main ways of utilizing coke oven gas in recent years. There are generally three ways to generate electricity from coke oven gas in China: steam power generation, gas turbine power generation, and internal combustion engine power generation. For independent coking plants, when using coke oven gas for power generation, gas internal combustion engine technology is often used, which has a small equipment investment and low cost of coke oven gas, resulting in significant economic benefits. For large and medium-sized domestic steel enterprises, when using coke oven gas for power generation, they mostly adopt gas steam combined cycle power generation technology (CCPP), which generally has problems such as large one-time equipment investment, high maintenance and spare parts costs, and high electricity prices. From this perspective, using coke oven gas for power generation in coking plants within steel enterprises is not the best way.

　　3、焦爐煤氣生產(chǎn)純氫焦爐煤氣中氫氣資源相當豐富, 氫氣的體積百分含量超過50%。目前利用焦爐煤氣制氫的方法主要有深冷法和變壓吸附法。深冷法是利用焦爐氣中各主要成分冷凝溫度的不同, 以深度冷凍部分冷凝的方法使氫與其它氣體組分分離, 最后用液氮洗以脫除氣體中剩余的CO 和CH4, 最終得到的氣體中含有83% ~88%的氫, 其余為氮。深冷法是COG 制氫應用最早、技術最成熟的方法, 適宜于焦爐氣的綜合利用, 它不僅能回收氫氣, 還能回收CH4、CO等。但其缺點是所用設備復雜且需在高壓下操作, 這使得深冷裝置投資大、運轉(zhuǎn)費用高、投資回收期長, 因此難以被大多數(shù)焦化廠接受。變壓吸附法(PSA法) 是利用氣體組分在固體材料上吸附特性的差異以及吸附量隨壓力變化而變化的特性, 通過周期性的壓力變換過程實現(xiàn)氣體的分離或提純。PSA法利用焦爐煤氣生產(chǎn)純H2, 在我國已有多年的歷史, 其生產(chǎn)技術成熟, 經(jīng)濟合理, 特別是與水電解法制H2比較,效益更顯著。但焦爐煤氣生產(chǎn)純H2存在必須具備管道輸送的固定用戶的限制, 一旦用戶發(fā)生變化, 很難維持正常生產(chǎn), 只能轉(zhuǎn)產(chǎn)。綜上所述, 雖然利用焦爐煤氣生產(chǎn)氫氣的技術成熟且經(jīng)濟合理, 但受氫氣產(chǎn)量的限制, 其焦爐煤氣消耗量并不大。因此, 制氫氣并不能作為鋼鐵企業(yè)利用焦爐煤氣的主要途徑。

　　3. The production of pure hydrogen from coke oven gas is rich in hydrogen resources, with a volume percentage content of over 50%. At present, the main methods for producing hydrogen using coke oven gas are cryogenic method and pressure swing adsorption method. The cryogenic method utilizes the different condensation temperatures of the main components in coke oven gas to separate hydrogen from other gas components through deep freezing partial condensation. Finally, the gas is washed with liquid nitrogen to remove the remaining CO and CH4. The resulting gas contains 83% to 88% hydrogen and the rest is nitrogen. The cryogenic method is the earliest and most mature application of COG hydrogen production technology, suitable for the comprehensive utilization of coke oven gas. It can not only recover hydrogen, but also recover CH4, CO, etc. But its disadvantage is that the equipment used is complex and needs to be operated under high pressure, which makes the investment of cryogenic equipment large, the operating cost high, and the investment recovery period long, making it difficult for most coking plants to accept. The pressure swing adsorption (PSA) method utilizes the differences in adsorption characteristics of gas components on solid materials and the characteristic that the adsorption amount changes with pressure, to achieve gas separation or purification through periodic pressure transformation processes. The PSA method uses coke oven gas to produce pure H2, which has a history of many years in China. Its production technology is mature and economically reasonable, especially compared with the water electrolysis method for H2, the benefits are more significant. However, the production of pure H2 from coke oven gas has the limitation of having a fixed user for pipeline transportation. Once the user changes, it is difficult to maintain normal production and can only be converted. In summary, although the technology of using coke oven gas to produce hydrogen is mature and economically reasonable, its consumption of coke oven gas is not significant due to the limitation of hydrogen production. Therefore, hydrogen production cannot be the main way for steel enterprises to utilize coke oven gas.

　　4、合成甲醇焦爐煤氣組分中甲烷含量(體積分數(shù)) 為24% ~ 28%, 只需將甲烷轉(zhuǎn)化成一定比例的CO和H2, 即可大體滿足合成甲醇的合成氣比例要求。合成甲醇的主要反應如下:CO+2H2=CH3OH+QCO2+3H2=CH3OH+H2O+Q煤氣中甲烷及高碳烴轉(zhuǎn)化成合成氣后, 在60MPa壓強下即可完成甲醇合成, 流程短, 反應速度快, 焦爐煤氣利用率高, 一般2000~2200m3焦爐煤氣生產(chǎn)1t甲醇。對于鋼鐵企業(yè)而言, 要利用焦爐煤氣合成甲醇主要存在以下兩方面問題:

　　4. The methane content (volume fraction) in the composition of the coke oven gas for synthesizing methanol is 24% to 28%. By converting methane into a certain proportion of CO and H2, the synthesis gas ratio requirements for synthesizing methanol can be roughly met. The main reactions for synthesizing methanol are as follows: CO+2H2=CH3OH+QCO2+3H2=CH3OH+H2O+Q After methane and high carbon hydrocarbons in the gas are converted into synthesis gas, methanol synthesis can be completed at a pressure of 60MPa. The process is short, the reaction rate is fast, and the utilization rate of coke oven gas is high. Generally, 2000-2200m3 coke oven gas produces 1 ton of methanol. For steel enterprises, there are two main problems in using coke oven gas to synthesize methanol:

　　①需要有充足的焦爐煤氣富余量。生產(chǎn)1t甲醇需消耗2000~2200m3 的焦爐煤氣, 一個年產(chǎn)10萬t甲醇的項目每小時焦爐煤氣的消耗量為25000m3。

　　① Adequate surplus coke oven gas is required. Producing 1 ton of methanol requires a consumption of 2000-220m3 of coke oven gas, and a project with an annual output of 100000 tons of methanol consumes 25000 m3 of coke oven gas per hour.

　　②投資規(guī)模較大。一個年產(chǎn)20萬t甲烷的項目, 總投資高達4億元。

　　② The investment scale is relatively large. A project with an annual output of 200000 tons of methane, with a total investment of up to 400 million yuan.

　　5、生產(chǎn)直接還原鐵理論上講, 焦爐煤氣不需要經(jīng)過熱裂解, 就可直接供給氣基豎爐生產(chǎn)海綿鐵。其工藝過程為: 將焦爐煤氣和豎爐頂氣混合而成的還原氣在加熱爐中加熱, 然后直接通入到直接還原爐中生產(chǎn)直接還原鐵(DRI)。在此過程中, 焦爐煤氣作為還原過程的還原氣, 而高爐煤氣則作為燃料用于加熱還原氣體。然而, 利用焦爐煤氣生產(chǎn)直接還原鐵, 雖然技術上可行, 但距離規(guī)模化、產(chǎn)業(yè)化應用還有一定的距離。焦爐煤氣生產(chǎn)DRI沒有發(fā)展起來,有兩大主要原因:

　　5. In theory, direct reduction iron production can be achieved by supplying coke oven gas directly to a gas based vertical furnace for sponge iron production without the need for thermal cracking. The process involves heating the reducing gas made by mixing coke oven gas and vertical furnace top gas in a heating furnace, and then directly introducing it into a direct reduction furnace to produce direct reduced iron (DRI). During this process, coke oven gas is used as the reducing gas for the reduction process, while blast furnace gas is used as fuel to heat the reducing gas. However, although the use of coke oven gas to produce directly reduced iron is technically feasible, there is still a certain distance to go before it can be scaled up and industrialized. There are two main reasons why the production of DRI from coke oven gas has not developed:

　　(1) 焦爐煤氣資源問題對于鋼鐵企業(yè)內(nèi)部的焦化廠而言, 焦爐煤氣主要用于鋼鐵廠內(nèi)熱能平衡, 其富余的焦爐煤氣量不足以供應DRI的生產(chǎn)需求。而對于獨立焦化企業(yè)而言, 焦爐煤氣約40%~50%用于加熱焦爐, 其剩余氣量也很難滿足DRI生產(chǎn)的需要。近幾年來, 雖然焦炭生產(chǎn)能力大幅度提高, 產(chǎn)生了大量富余焦爐煤氣。然而, 根據(jù)Midrex 法換算, 生產(chǎn)1tDRI需要約700m3焦爐煤氣, 年產(chǎn)100萬tDRI需7億m3焦爐煤氣, 相當于一個300萬t的焦化廠一年產(chǎn)生的全部焦爐煤氣量。無論是鋼鐵廠中的焦化廠還是獨立焦化廠, 目前都很難在一個地點集中7億m3 的焦爐煤氣。

　　(1) For coking plants within steel enterprises, the issue of coke oven gas resources is mainly used for thermal energy balance. The surplus coke oven gas is not sufficient to meet the production needs of DRI. For independent coking enterprises, about 40% to 50% of coke oven gas is used to heat the coke oven, and the remaining gas volume is also difficult to meet the needs of DRI production. In recent years, although the production capacity of coke has significantly increased, a large amount of surplus coke oven gas has been generated. However, according to the Midrex method, producing 1 tDRI requires approximately 700 m3 of coke oven gas, and producing 1 million tDRI annually requires 700 million m3 of coke oven gas, which is equivalent to the total amount of coke oven gas produced by a 3 million ton coking plant in one year. It is currently difficult to concentrate 700 million cubic meters of coke oven gas in one location, whether it is a coking plant in a steel plant or an independent coking plant.

　　(2) 富鐵礦資源問題生產(chǎn)DRI是固態(tài)還原, 與高爐煉鐵相比,不能排渣, 因此要求鐵礦品位在66%以上。中國沒有高品位鐵礦, 要生產(chǎn)直接還原鐵必須依賴人造富礦或進口高品位鐵礦, 而這大幅增加了生產(chǎn)DRI的成本, 為焦爐煤氣生產(chǎn)直接還原鐵制造了障礙。綜上所述, 在目前的原料、燃料條件下, 要將焦爐煤氣生產(chǎn)直接還原鐵技術規(guī)模化、產(chǎn)業(yè)化仍有一段較長的路要走。

　　(2) The production of DRI from rich iron ore resources requires solid-state reduction, which cannot discharge slag compared to blast furnace ironmaking. Therefore, it is required that the iron ore grade be above 66%. China does not have high-grade iron ore, and to produce direct reduced iron, it must rely on artificial rich ore or imported high-grade iron ore, which significantly increases the cost of producing DRI and creates obstacles for the production of direct reduced iron from coke oven gas. In summary, under the current conditions of raw materials and fuels, there is still a long way to go to scale and industrialize the direct reduction of iron technology from coke oven gas production.

　　6、高爐噴吹焦爐煤氣高爐噴吹焦爐煤氣是指將焦爐產(chǎn)生的多余的焦爐煤氣經(jīng)過凈化處理, 通過設備加壓至高于風口壓力, 然后利用類似噴煤的噴吹設施, 通過各個支管噴入高爐風口。高爐噴吹焦爐煤氣的主要工藝特點如下:

　　6. Blast furnace injection of coke oven gas refers to purifying the excess coke oven gas produced by the coke oven, pressurizing it to a pressure higher than the tuyere pressure through equipment, and then using injection facilities similar to coal injection to inject it into the tuyere of the blast furnace through various branch pipes. The main process characteristics of injecting coke oven gas into blast furnaces are as follows:

　　①為高爐提供更好的還原劑;

　　① Provide better reducing agents for blast furnaces;

　　②還原產(chǎn)物環(huán)保;

　　② Environmental protection of reduced products;

　　③提高焦爐煤氣價值, 改善能量利用率;

　　③ Enhance the value of coke oven gas and improve energy utilization efficiency;

　　④噴吹工藝簡便, 技術成熟, 設備投資小。目前高爐噴吹焦爐煤氣的最大問題是焦爐煤氣的來源。作為優(yōu)質(zhì)燃料的焦爐煤氣在各鋼鐵廠普遍存在著供應緊缺的現(xiàn)象。然而, 從國內(nèi)總體狀況和各企業(yè)的實際情況分析, 仍然存在許多規(guī)模和數(shù)量不等的焦爐煤氣供應源。對于有焦化廠的鋼鐵聯(lián)合企業(yè), 自產(chǎn)焦爐煤氣基本得到利用,主要用于焦爐加熱、軋鋼加熱爐、高爐熱風爐、燒結點火以及燃燒發(fā)電等。但是, 隨著企業(yè)內(nèi)能量利用率的提高和替代燃料的使用, 加熱所需要的焦爐煤氣將不斷減少, 焦爐煤氣會有一定的富裕量供高爐噴吹。另外, 基于上面的分析, 將焦爐煤氣用于發(fā)電的成本遠遠高于將焦爐煤氣用于高爐噴吹, 所以將用于發(fā)電的焦爐煤氣也改用高爐噴吹, 則能更好地體現(xiàn)焦爐煤氣的價值和使用效果。

　　④ The spraying process is simple, the technology is mature, and the equipment investment is small. The biggest problem with injecting coke oven gas into blast furnaces at present is the source of coke oven gas. As a high-quality fuel, coke oven gas is commonly in short supply in various steel plants. However, based on the overall situation in China and the actual situation of various enterprises, there are still many coke oven gas supply sources of varying scales and quantities. For steel joint ventures with coking plants, self-produced coke oven gas is basically utilized, mainly used for coke oven heating, steel rolling heating furnace, blast furnace hot blast stove, sintering ignition, and combustion power generation. However, with the improvement of energy utilization efficiency within enterprises and the use of alternative fuels, the amount of coke oven gas required for heating will continue to decrease, and there will be a certain surplus of coke oven gas for blast furnace injection. In addition, based on the above analysis, the cost of using coke oven gas for power generation is much higher than using coke oven gas for blast furnace injection. Therefore, switching to blast furnace injection for coke oven gas used for power generation can better reflect the value and effectiveness of coke oven gas.

　　因此, 對鋼鐵聯(lián)合企業(yè)來說, 應盡可能多地將焦爐煤氣供給高爐噴吹。綜上所述, 高爐噴吹焦爐煤氣具有工藝成熟、設備技術投資小、運行成本低等優(yōu)點。但是需要特別指出的是, 在焦爐煤氣的供應量相對并不多, 且存在一定的波動的情況下, 高爐噴吹焦爐煤氣不是噴煤的替代品, 而是噴煤的補充和完善, 以期獲得最佳的經(jīng)濟效益。

　　Therefore, for steel joint ventures, as much coke oven gas as possible should be supplied to blast furnaces for injection. In summary, injecting coke oven gas into blast furnaces has the advantages of mature technology, low equipment and technology investment, and low operating costs. However, it should be pointed out that in the case where the supply of coke oven gas is relatively small and there are certain fluctuations, injecting coke oven gas into blast furnaces is not a substitute for coal injection, but a supplement and improvement to coal injection, in order to achieve the best economic benefits.

　　結論

　　Conclusion

　　(1) 焦爐煤氣用作加熱燃料, 仍是目前焦爐煤氣的主要利用途徑之一, 但焦爐煤氣的需求量正在逐漸下降。

　　(1) The use of coke oven gas as heating fuel is still one of the main ways of utilizing coke oven gas, but the demand for coke oven gas is gradually decreasing.

　　(2) 對于獨立焦化廠而言, 利用焦爐煤氣發(fā)電時經(jīng)濟效益顯著。而對于國內(nèi)大中型鋼鐵企業(yè)而言, 利用焦爐煤氣發(fā)電時, 普遍存在設備一次性投資大、維護及備件費用高、電價居高不下等問題。

　　(2) For independent coking plants, the economic benefits are significant when using coke oven gas for power generation. For large and medium-sized domestic steel enterprises, when using coke oven gas for power generation, there are generally problems such as large one-time equipment investment, high maintenance and spare parts costs, and high electricity prices.

　　(3) 利用焦爐煤氣生產(chǎn)氫氣的技術成熟且經(jīng)濟合理, 但受氫氣產(chǎn)量的限制, 其并不能作為鋼鐵企業(yè)利用焦爐煤氣的主要途徑。

　　(3) The technology of using coke oven gas to produce hydrogen is mature and economically reasonable, but due to the limitation of hydrogen production, it cannot be used as the main way for steel enterprises to utilize coke oven gas.

　　(4) 目前利用焦爐煤氣生產(chǎn)甲醇的焦化廠多為獨立焦化廠。對于鋼鐵企業(yè)而言, 其主要存在的問題是, 沒有充足的焦爐煤氣富余量且投資規(guī)模較大。

　　(4) At present, most coking plants that use coke oven gas to produce methanol are independent coking plants. For steel companies, the main problem is the lack of sufficient surplus coke oven gas and large investment scale.

　　(5) 利用焦爐煤氣生產(chǎn)直接還原鐵技術, 雖然在技術上可行, 但在目前的原料、燃料條件下,要將其規(guī)模化、產(chǎn)業(yè)化仍有一段較長的路要走。

　　(5) Although the technology of using coke oven gas to produce direct reduced iron is technically feasible, there is still a long way to go to scale and industrialize it under current raw material and fuel conditions.

　　(6)高爐噴吹焦爐煤氣技術具有工藝成熟、設備技術投資小、運行成本低等優(yōu)點。而且, 其最終還原產(chǎn)物為水, 這樣就減少了高爐的CO2排放, 對于高爐的節(jié)能減排具有十分重要的意義。

　　(6) The technology of injecting coke oven gas into blast furnaces has the advantages of mature process, low equipment and technology investment, and low operating costs. Moreover, its final reduction product is water, which reduces the CO2 emissions of the blast furnace and is of great significance for energy conservation and emission reduction of the blast furnace.

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