(Daily Question) Coal-to-Oil and Olefins Forum, 1.18.2018
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3.jpg Participation: Prize of 5 Wealth； Correct answer: Reward of 10 wealth points ； Note: This post is valid for 48 hours. Question: What are the causes of butter formation in the alkaline scrubber tower of the (DMTO) olefin separation unit? In the presence of alkali, the unsaturated hydrocarbons in the feed gas undergo polymerization, producing a viscous liquid that accumulates within the system (it is called \"butter\" because it turns yellow when exposed to air), causing blockages in the trays, pipes, and equipment and thereby affecting the operation of the system. Note: The answers will be released automatically in two days!
In the presence of alkali, the unsaturated hydrocarbons in the feed gas undergo polymerization, producing a viscous liquid that accumulates within the system (it is called \"butter\" because it turns yellow when exposed to air), causing blockages in the trays, pipes, and equipment and thereby affecting the operation of the system.
First, during the alkaline washing process of the pyrolysis gas, dienes or other unsaturated hydrocarbons that condense or dissolve in the alkaline solution may generate free radicals under the influence of trace amounts of oxygen, thereby providing the conditions necessary for the formation of cross-linked polymers. Secondly, aldehydes in the pyrolysis gas, or those present under alkaline conditions, can easily undergo condensation reactions to form β-hydroxyaldehydes, which then undergo further addition reactions to produce polymers with a certain molecular weight.
The formation of (butter): It results from a saponification reaction that occurs when organic acids react with alkalis; the product that is formed is yellow in color, and this is what is known as butter.
Answer: In the presence of alkali, the unsaturated hydrocarbons in the feed gas undergo polymerization, forming viscous liquids that accumulate within the system (they are called “butter” because they turn yellow when exposed to air), causing blockages in the trays, pipes, and equipment and thereby affecting the operation of the system.
There are two reasons for the formation of butter in the alkali washing system: first, dienes or other unsaturated hydrocarbons that condense or dissolve in the alkaline solution during the alkali washing process can easily form free radicals under the influence of a small amount of oxygen and metal ions; these free radicals provide the conditions necessary for the formation of cross-linked polymers, resulting in the creation of butter； Another reason is that the aldehydes in the pyrolysis gas, or those present alongside them, can easily undergo condensation reactions under the action of a base to form butter.
First, dienes or other unsaturated hydrocarbons that condense or dissolve in the alkaline solution during the alkali washing process can, under the influence of trace amounts of oxygen, generate free radicals, thereby creating conditions for the formation of cross-linked polymers, as shown in equations (1) to (3)； Secondly, the aldehydes in the reaction gas, or those with active hydrogen atoms on the α-carbon atoms, are prone to undergo Aldol condensation reactions under the action of a base; or, under the influence of the strong base NaOH, they undergo addition reactions to form β-hydroxyaldehydes, which then further undergo addition reactions to form polymers with a certain molecular weight
In the presence of alkali, the unsaturated hydrocarbons in the feed gas undergo polymerization, producing a viscous liquid that accumulates within the system (it is called \"butter\" because it turns yellow when exposed to air), causing blockages in the trays, pipes, and equipment and thereby affecting the operation of the system.
One approach is that dienes or other unsaturated hydrocarbons, which condense or dissolve in the alkaline solution during the alkali washing process, form free radicals under the action of trace amounts of oxygen and metal ions, thereby initiating a reaction that leads to the formation of cross-linked polymers. Secondly, the aldehydes in the product gas, or those present together with alkalis, can easily trigger ALdol condensation reactions.
Answer: In the presence of alkali, the unsaturated hydrocarbons in the feed gas undergo polymerization, producing a viscous liquid that accumulates within the system (it is called \"butter\" because it turns yellow when exposed to air), causing blockages in the trays, pipes, and equipment and thus affecting the operation of the system.