Abstract:
The invention relates to a method for cleaving Michael adducts that are contained in a fluid F at a weight proportion of = 10 wt % and that were formed in the production of acrylic acid or esters thereof, in a cleaving device, which comprises a pump P and a separation column K having installations that effect separation and a recirculation heat exchanger UW, wherein for the purpose of feeding the cleaving energy, the pump P draws sump fluid from the sump chamber of the separation column K and continuously feeds said sump fluid back into the sump chamber above the level of the sump fluid through the recirculation heat exchanger UW, and wherein the pump P is a radial centrifugal pump having an open impeller.
Abstract:
The invention relates to a method for separating a raw acrylic acid from a product gas mixture comprising glyoxal as auxiliary product of a heterogeneously catalyzed partial gas phase oxidation of at least one C3-precursor compound, comprising the absorption of the acrylic acid in a high-boiling absorption agent and the rectificative processing of the resulting absorbent, and wherein, in a distillation unit, an absorption agent contained in the sump fluid that has been removed from the sump chamber of the absorption column is distilled and is fed back into the absorption before remaining high-boiling components are removed, and wherein the glyoxal content of the raw acrylic acid is reduced by limiting the duration of the high-boiling components in the distillation unit.
Abstract:
A method is disclosed for transferring heat to a liquid F containing dissolved monomeric acrylic acid, acrylic acid oligomers obtained by Michael addition, and acrylic acid polymer with the help of an indirect heat exchanger to which the liquid F is fed at a temperature TF = 150°C and a heat transfer fluid W is fed at a temperature Tw > TF. In said method, gas bubbles or thin layers of liquid F bordering a gas phase are generated in the liquid F while said liquid F flows through the heat exchanger.
Abstract:
Ein Verfahren zur Rückspaltung von in einer Flüssigkeit F mit einem Gewichtsanteil von ≧ 10 Gew.-% enthaltenen Michael-Addukten, die bei der Herstellung von Acrylsäure oder deren Ester gebildet wurde, in einer Rückspaltvorrichtung, die eine Pumpe P, eine Trennkolonne K mit trennwirksamen Einbauten und einem Umlaufwärmeaustauscher UW umfasst, wobei zum Zwecke der Zufuhr der Spaltenergie die Pumpe P aus dem Sumpfraum der Trennkolonne K Sumpfflüssigkeit ansaugt und über dem Umlaufwärmeaustauscher UW laufend oberhalb des Stands der Sumpfflüssigkeit in den Sumpfraum zurückführt und wobei die Pumpe P eine Radialkreiselpumpe mit offenem Laufrad ist.
Abstract:
Separating acrylic acid, contained as main constituent and glyoxal, contained as by-product from a gaseous product mixture of a partial gas phase oxidation of 3C-precursor compound of acrylic acid comprises producing a liquid phase containing at least 70 wt.% of acrylic acid and at least 200 mol.ppm of glyoxal in relation to the contained molar quantity of acrylic acid and separating glyoxal from the acrylic acid by crystallization from the liquid phase, where the acrylic acid is formed in crystallite form and the glyoxal is enriched in the mother liquor remained after crystallization.
Abstract:
A process for transferring heat to a liquid F comprising dissolved monomeric acrylic acid, Michael acrylic acid oligomers, and acrylic acid polymer with the aid of an indirect heat exchanger to which are supplied the liquid F with a temperature TF of >=150° C. and a fluid heat carrier W with a temperature of TW>TF, wherein the formation of gas bubbles and/or of thin layers of liquid F adjoining a gas phase is brought about in the liquid F during the flow through the heat exchanger.
Abstract:
processo para inibir a polimerização por radical livre não desejada do ácido acrílico, e, fase líquida. um processo para inibir a polimerização por radical livre não desejada do ácido acrílico presente em uma fase líquida p cujo teor do ácido acrílico é de pelo menos 10% em peso e que, com base no peso do ácido acrílico presente neste, adicionalmente compreende pelo menos 100 ppm em peso de ácido propiônico e de pelo menos 100ppm em peso de glioxal, em que pelo menos um composto químico do elemento cobre é adicionado à fase líquida p e as fases p líquidas resultantes às quais um composto líquido do elemento cobre foi adicionado.