Abrégé

Disclosed are a formaldehyde absorption process device and method in polyoxymethylene dimethyl ether synthesis. In the process, higher-boiling-point intermediate component dimer PODE2 of polyoxymethylene dimethyl ether is used, and the amount of dissolved formaldehyde is much higher than that of methylal, so as to obtain a PODE2 solution of formaldehyde, so that operation pressures and temperatures in subsequent reactions are on lower levels, thereby avoiding the self-polymerization and disproportionation reaction of the formaldehyde, further, avoiding the pipeline blockage, lowering the acid content in the polyoxymethylene dimethyl ether product, and finally improving the yield of the product.

Classes IPC  ?

• C07C 43/30 - Composés comportant des groupes
• C07C 41/56 - Préparation de composés comportant des groupes par des réactions donnant des groupes par condensation d'aldéhydes, de paraformaldéhyde ou de cétones
• C07C 41/58 - SéparationPurificationStabilisationEmploi d'additifs

Abrégé

Disclosed are a process device and a method for synthesis of polymethoxy dimethyl ether from a formaldehyde gas and deacidification, wherein a packed section packed with a solid acidic catalyst is provided in a packed reaction tower, and a spray system and a bubbling absorption section are respectively provided above or below the packed section; moreover, a methylal inlet and a formaldehyde gas inlet are respectively provided on the upper part and the lower part of the packed reaction tower, the methylal inlet is connected with the spray system, the formaldehyde gas inlet extends into the bubbling absorption section through a pipeline, and the bubbling absorption section further forms circulating connection with the methylal inlet through a pipeline and a pump; furthermore, a reaction liquid outlet and a methyl formate outlet are further respectively provided at the bottom and top of the packed reaction tower. The formaldehyde gas refining process of the present invention is more simple and has lower costs, with synthesized polymethoxyl dimethyl ether by multi/trimerization being replaced by a formaldehyde gas, having a higher conversion rate; moreover, the process is simpler and the energy consumption and production costs are lower.

Classes IPC  ?

• C07C 41/56 - Préparation de composés comportant des groupes par des réactions donnant des groupes par condensation d'aldéhydes, de paraformaldéhyde ou de cétones
• C07C 43/30 - Composés comportant des groupes
• C07C 45/78 - SéparationPurificationStabilisationEmploi d'additifs
• C07C 45/85 - SéparationPurificationStabilisationEmploi d'additifs par traitement donnant lieu à une modification chimique
• C07C 47/058 - SéparationPurificationStabilisationEmploi d'additifs
• C07C 67/08 - Préparation d'esters d'acides carboxyliques par réaction d'acides carboxyliques ou d'anhydrides symétriques avec le groupe hydroxyle ou O-métal de composés organiques
• C07C 69/06 - Esters d'acide formique de composés monohydroxylés

Abrégé

Disclosed is a paraformaldehyde production method. A formaldehyde solution is used as the raw material, and is evaporated and concentrated to produce fine, soluble, and fluid paraformaldehyde after spray granulation in a spray granulation tower. The paraformaldehyde is transformed into a fluidized bed for drying, thereby obtaining dry paraformaldehyde particles; after concentration, formaldehyde is delivered to the spray granulation tower under a constant pressure and blown out of the top of the tower; at the same time, nitrogen gas and formaldehyde are delivered into the top portion of the spray granulation tower to conduct contact heat exchange in parallel flows. In the present invention, formaldehyde is delivered under a constant pressure and by means of a specially made nozzle, such that the formaldehyde solution can be rapidly dispersed and conduct contact heat exchange with nitrogen gas in parallel flows, thereby ensuring the degree of polymerization and degree of consistency in particle diameters for the paraformaldehyde product. Additionally, paraformaldehyde particles in a cyclonic separator is recovered and delivered to the granulation tower, thereby further enhancing the size consistency of the paraformaldehyde products.

Classes IPC  ?

• C08G 2/08 - Polymérisation du formaldéhyde
• C08G 2/28 - Traitements de post-polymérisation
• C08G 4/00 - Polymères de condensation d'aldéhydes ou de cétones et de poly-alcoolsPolymères d'addition de composés hétérocycliques oxygénés contenant dans leur cycle au moins une fois le groupement —O—C—O—

Abrégé

Disclosed is a paraformaldehyde production apparatus, comprising a formaldehyde evaporation and concentration apparatus, a spray granulation tower, a fluidized bed dryer, a cyclonic separator, and a tail gas absorption apparatus. The present invention uses a constant-pressure delivery apparatus with a specially made nozzle such that a formaldehyde solution sprays with a high degree of dispersion, and a target paraformaldehyde product having consistent sizes and a degree of polymerization of around 11 is obtained. Heat and residual solid paraformaldehyde are maximally recovered and delivered back to a granulation tower for accelerated drying and granulation, thereby reducing energy consumption, conserving energy, and lowering production cost.

Classes IPC  ?

• C08G 2/08 - Polymérisation du formaldéhyde
• C08G 2/28 - Traitements de post-polymérisation
• C08G 4/00 - Polymères de condensation d'aldéhydes ou de cétones et de poly-alcoolsPolymères d'addition de composés hétérocycliques oxygénés contenant dans leur cycle au moins une fois le groupement —O—C—O—