Liquid fuels contain a large variety of sulfur compounds (thiols, sulfides, disulfides and thiophenes), which generate SO2 and airborne particulate emissions during combustion. Therefore, desulfurization of light oil is extremely important in the petroleum-processing industry. Several processes have been proposed in the past to deal with the problem of removing these compounds from light oil. The most important and common industrial process is that of treating the fuel under high temperatures and high pressures with hydrogen. This process is called hydrodesulfurization (HDS) and has received extensive attention since its discovery in 1930’s. Literature describing this technology is tremendous,
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amounting to thousands of patents and scientific and engineering papers.1-4 HDS is a process in which light oil is heated, mixed with hydrogen, and fed to a reactor packed with a pelleted catalyst. Temperatures in the reactor typically range from 300 to 380 0C. At these temperatures, some or all of the feed is vaporized, depending on the boiling range of the feed and the pressure in the unit. For heavier feeds it is common for the majority of the feed to be liquid. Reaction pressures range from as low as 15 to as high as 90 bar depending on the difficulty of removing the sulfur.4 In the production of light oil such as diesel or jet fuel, pressures higher than 30 bar are commonly used.2 In the earlier processes the feed and hydrogen mixture flow downward through the reactor, passing around and through the particulate catalyst, however in newer reactor configurations hydrogen flows upward from the bottom of the reactor (Synsat process).4 Upon leaving the reactor, the mixture of treated fuel and hydrogen flows through a series of mechanical devices to separate and recycle the hydrogen, remove the H2S generated in the reaction, and recover the desulfurized product. HDS catalysts slowly lose activity during the operation, and must be removed and replaced after approximately two years of on-stream operation. As used in large integrated refineries, HDS is very effective and relatively inexpensive. However, the HDS is limited in treating benzothiophenes (BTs) and dibenzothiophenes (DBTs), especially DBTs having alkyl substituents on their 4 and/or 6 positions (Scheme 1).1-3 The production of light oil, with very low levels of sulfur-containing compounds, therefore requires inevitably the application of severe operating conditions i.e., very low space velocities, high temperatures and high pressures, as well as the use of highly active catalysts.1-4 An alternative process, able to be operated under moderate conditions and without requirements for H2 and catalysts, is therefore nowadays required.1,
เชื้อเพลิงเหลวที่ประกอบด้วยความหลากหลายของสารประกอบกำมะถัน (thiols, sulfides, disulfides และ thiophenes), ซึ่งสร้าง SO2 และฝุ่นปล่อยอากาศในระหว่างการเผาไหม้ ดังนั้น desulfurization น้ำมันแสงเป็นสิ่งสำคัญมากในอุตสาหกรรมแปรรูปปิโตรเลียม กระบวนการต่าง ๆ ที่ได้รับการเสนอชื่อในอดีตเพื่อจัดการกับปัญหาของการเอาสารเหล่านี้จากไฟน้ำมัน กระบวนการอุตสาหกรรมทั่วไป และสำคัญที่สุดคือที่รักษาเชื้อเพลิงภายใต้อุณหภูมิสูงและความดันสูงกับไฮโดรเจน กระบวนการนี้เรียกว่า hydrodesulfurization (ฉีดน้ำ HDS) และได้รับความสนใจมากมายตั้งแต่การค้นพบใน 1930's ประกอบการอธิบายเทคโนโลยีนี้เป็นอย่างมาก2amounting to thousands of patents and scientific and engineering papers.1-4 HDS is a process in which light oil is heated, mixed with hydrogen, and fed to a reactor packed with a pelleted catalyst. Temperatures in the reactor typically range from 300 to 380 0C. At these temperatures, some or all of the feed is vaporized, depending on the boiling range of the feed and the pressure in the unit. For heavier feeds it is common for the majority of the feed to be liquid. Reaction pressures range from as low as 15 to as high as 90 bar depending on the difficulty of removing the sulfur.4 In the production of light oil such as diesel or jet fuel, pressures higher than 30 bar are commonly used.2 In the earlier processes the feed and hydrogen mixture flow downward through the reactor, passing around and through the particulate catalyst, however in newer reactor configurations hydrogen flows upward from the bottom of the reactor (Synsat process).4 Upon leaving the reactor, the mixture of treated fuel and hydrogen flows through a series of mechanical devices to separate and recycle the hydrogen, remove the H2S generated in the reaction, and recover the desulfurized product. HDS catalysts slowly lose activity during the operation, and must be removed and replaced after approximately two years of on-stream operation. As used in large integrated refineries, HDS is very effective and relatively inexpensive. However, the HDS is limited in treating benzothiophenes (BTs) and dibenzothiophenes (DBTs), especially DBTs having alkyl substituents on their 4 and/or 6 positions (Scheme 1).1-3 The production of light oil, with very low levels of sulfur-containing compounds, therefore requires inevitably the application of severe operating conditions i.e., very low space velocities, high temperatures and high pressures, as well as the use of highly active catalysts.1-4 An alternative process, able to be operated under moderate conditions and without requirements for H2 and catalysts, is therefore nowadays required.1,
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Liquid fuels contain a large variety of sulfur compounds (thiols, sulfides, disulfides and thiophenes), which generate SO2 and airborne particulate emissions during combustion. Therefore, desulfurization of light oil is extremely important in the petroleum-processing industry. Several processes have been proposed in the past to deal with the problem of removing these compounds from light oil. The most important and common industrial process is that of treating the fuel under high temperatures and high pressures with hydrogen. This process is called hydrodesulfurization (HDS) and has received extensive attention since its discovery in 1930’s. Literature describing this technology is tremendous,
2
amounting to thousands of patents and scientific and engineering papers.1-4 HDS is a process in which light oil is heated, mixed with hydrogen, and fed to a reactor packed with a pelleted catalyst. Temperatures in the reactor typically range from 300 to 380 0C. At these temperatures, some or all of the feed is vaporized, depending on the boiling range of the feed and the pressure in the unit. For heavier feeds it is common for the majority of the feed to be liquid. Reaction pressures range from as low as 15 to as high as 90 bar depending on the difficulty of removing the sulfur.4 In the production of light oil such as diesel or jet fuel, pressures higher than 30 bar are commonly used.2 In the earlier processes the feed and hydrogen mixture flow downward through the reactor, passing around and through the particulate catalyst, however in newer reactor configurations hydrogen flows upward from the bottom of the reactor (Synsat process).4 Upon leaving the reactor, the mixture of treated fuel and hydrogen flows through a series of mechanical devices to separate and recycle the hydrogen, remove the H2S generated in the reaction, and recover the desulfurized product. HDS catalysts slowly lose activity during the operation, and must be removed and replaced after approximately two years of on-stream operation. As used in large integrated refineries, HDS is very effective and relatively inexpensive. However, the HDS is limited in treating benzothiophenes (BTs) and dibenzothiophenes (DBTs), especially DBTs having alkyl substituents on their 4 and/or 6 positions (Scheme 1).1-3 The production of light oil, with very low levels of sulfur-containing compounds, therefore requires inevitably the application of severe operating conditions i.e., very low space velocities, high temperatures and high pressures, as well as the use of highly active catalysts.1-4 An alternative process, able to be operated under moderate conditions and without requirements for H2 and catalysts, is therefore nowadays required.1,
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