【Q&A No. 025】2018.01.25
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【Q&A No. 025】January 25, 2018: What is the effect of changes in space velocity on the conversion reaction? “The conversion load is generally expressed in terms of liquid volume space velocity or carbon space velocity. The higher the space velocity, the shorter the residence time. With other process conditions constant, an increase in space velocity leads to an increase in residual methane at the outlet and greater carbon deposition on the catalyst. In actual industrial units, the space velocity is related to the dry point of the feed oil, its aromatic content, and the temperature at the outlet of the bed, in order to meet the requirements of a satisfactory conversion process. The determination of the aforementioned process parameters is also related to the properties of the conversion catalyst selected, so it can only be determined based on specific circumstances. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Due to the limitations on the number of posts in the “One Question per Day” section, “One Image per Day” has been moved to the registered devices section; you can access it through the directory I posted. For management purposes, if you need to view content from a few days ago, please go through the summary post below. 2018 Chemical Engineering Technology Training – Daily Question Summary Thread: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=18889712018 Registered Equipment Section – Daily Image Summary Thread: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888970
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The conversion rate of hydrocarbons decreases as the space velocity increases, because a higher space velocity results in a shorter residence time of the feed gas on the catalyst, leading to less complete conversion reactions. A suitable space velocity should be selected based on factors such as the temperature of the conversion process, the CH4 conversion rate, the composition of the feed gas, and the catalyst activity. (i.e., excessive air velocity leads to a decrease in conversion depth)
Generally, the higher the space velocity, the lower the conversion rate and the higher the selectivity; it is also possible for the conversion rate to increase first and then decrease as the space velocity increases
What is the effect of changes in air velocity on the conversion reaction? Answer: “Generally, the conversion load is expressed in terms of liquid volume space velocity or carbon space velocity.” The higher the space velocity, the shorter the residence time. With other process conditions constant, an increase in space velocity leads to an increase in residual methane at the outlet and greater carbon deposition on the catalyst. In actual industrial units, the space velocity is related to the dry point of the feed oil, its aromatic content, and the temperature at the outlet of the bed, in order to meet the requirements of a satisfactory conversion process. The determination of the aforementioned process parameters is also related to the properties of the conversion catalyst selected, so it can only be determined based on specific circumstances.
High space velocity, short residence time, mild reaction degree, and high conversion rate. Low air velocity, long residence time, high degree of reaction, and low conversion rate.
The high space velocity results in carbon monoxide and carbon dioxide not having enough time to react completely in the catalyst, leading to trace amounts that exceed the limits in the gas exiting the methanation reactor.
The conversion load is generally expressed in terms of liquid volume space velocity or carbon space velocity. The higher the space velocity, the shorter the residence time. With other process conditions constant, an increase in space velocity leads to an increase in residual methane at the outlet and greater coking of the catalyst. In actual industrial plants, the space velocity is related to the dry point of the light oil feedstock, its aromatic content, and the temperature at the outlet of the bed. When the dry point of the light oil feedstock increases or its aromatic content rises, the space velocity should be reduced accordingly in order to meet the desired requirements of the conversion process. The determination of the aforementioned process parameters is also related to the properties of the conversion catalyst selected, so it can only be determined based on specific circumstances.
The conversion load is generally expressed in terms of liquid volume space velocity or carbon space velocity. The higher the space velocity, the shorter the residence time. With other process conditions constant, an increase in space velocity leads to an increase in residual methane at the outlet and greater carbon deposition on the catalyst. In actual industrial units, the space velocity is related to the dry point of the feed oil, its aromatic content, and the temperature at the outlet of the bed, in order to meet the requirements of a satisfactory conversion process. The determination of the aforementioned process parameters is also related to the properties of the conversion catalyst selected; therefore, it can only be determined based on specific circumstances
The higher the space velocity, the shorter the residence time. With other process conditions constant, an increase in space velocity leads to an increase in residual methane at the outlet and greater coking of the catalyst.
The conversion load is generally expressed in terms of liquid volume space velocity or carbon space velocity. The higher the space velocity, the shorter the residence time. With other process conditions constant, an increase in space velocity leads to an increase in residual methane at the outlet and greater carbon deposition on the catalyst. In actual industrial units, the space velocity is related to the dry point of the feed oil, its aromatic content, and the temperature at the outlet of the bed, in order to meet the requirements of a satisfactory conversion process. The determination of the aforementioned process parameters is also related to the properties of the conversion catalyst selected, so it can only be determined based on specific circumstances.