Method of reducing foam in a primary fractionator

摘要

A method of operating a primary fractionator with soil redeposition in an ethylene plant undergoing foaming or bubbles by reducing soil redeposition and sudsing / bubbles and reducing pressure drop column, comprising the steps of : (a) feeding cracked gas to the primary fractionator, wherein (i) the primary fractionator experiences a severe deposition of dirt on the rectification section; (Ii) in which deposition of severe dirt is the result of a very rapid deposition of one or more compounds of dirt selected from the group consisting of polymers of styrene, indene, divinylbenzene, alpha-methylstyrene, indene, naphthalene, cyclic compounds upper and combinations thereof; (Iii) in which deposition of severe dirt has been caused not only on the surfaces of upper tray, but also on the surfaces of the lower tray, which results in a greater pressure drop in the column with their operational efficiencies minors; and (iv) in which the deposition of severe dirt due to the very rapid deposition of species of soil also results in greater and excessive foaming / bubble which, in turn, results in a further increase and very faster pressure drop in column and, thus, lower separation efficiencies of the column, as indicated by at least a ratio of liquid-gas contact, feed rate, reflux rate, top temperature product gas distilled to final temperature or pressure differential; wherein the method is characterized by (b) adding a composition to reduce foam reflux primary fractionator in an amount effective to reduce deposits of compounds of dirt and to reduce foaming / bubble composition foam reduction in the rectifying section of the primary fractionator by injection of the composition of foam reduction along with the reflux stream, wherein: (i) said composition reduction foam is selected from the group consisting of a polysiloxane, a copolymer of ethylene oxide-propylene oxide ethoxylate fatty acid, a polyisobutylene, an ester of fatty acid; and (ii) adding a composition to reduce foam in the above manner results in a reduction of soil redeposition by reducing deposits of compounds of dirt and reduced foaming / bubble, and a reduction in pressure drop column as observed by a color change gasoline brownish to its normal yellowish green color and through operational efficiencies improved as indicated by at least a ratio of liquid-gas contact, feed rate, reflux rate, higher product temperature, distilled gasoline final temperature or pressure differential; and thus it results in a prolongation of the time between two stops primary fractionator process.