ITRM20080479A1 - HIGH PERFORMANCE REACTOR FOR CONTINUOUS POLYMERIZATION OF SOLID STATE PET - Google Patents

Description

High performance modular reactor for continuous polymerization of solid-state PET.

DESCRIPTION

The invention relates to a modular reactor built with elements in series and mods in parallel.

At the present state of the art there are two types of reactors used in PET polymerization.

The first is a vertical cylindrical static type, in which the advancement of the product takes place by gravity.

The second is cylindrical with an almost horizontal axis, in which the polymer feed movement occurs due to the rotation of the reactor body.

With the static reactor with a single vertical body the limitations are as follows:

<-> Remarkable height of the process buildings.

<-> Production capacity for each plant of about 5001600 tons / day.

<-> Long time required for transport and construction of the plant.

<-> Bottleneck in plant management.

<-> Difficult and costly operational management due to the considerable amount of "working capital" polymer present in the reactor.

With the second type of single horizontal body reactor, the following limitations remain: <-> Production capacity per single plant of about 1300 bulls / day.

<-> Relatively high times and costs for transport and assembly due to the considerable dimensions involved are necessary.

<-> Bottle neck in the management of the system.

The present invention, as will be described below and shown in the attached screens (Table 1; Table 2; Table 3 and Table 4), allows to overcome all the limitations of current reactors.

The main feature of the conceived case is that the product is set in motion by exploiting the technique of vibrating channels, therefore with the possibility of a millimeter and gradual adjustment of the feed speed of the product itself. of the polymer bed in each element will be of the order of 1 meter, it will guarantee a “plug-flow” piston type advancement of the mass.

Specifies this, which is fundamental for obtaining a high degree of homogeneity of the chemical parameters characterizing the final product.

The relatively low bed height, with consequent limited static load, will avoid the presence of compression forces which, as occurs in current plants, are one of the main causes in the formation of more or less extensive agglomerations in the processed product.

Each basic element, see Table 1, is equipped with an independent counter-current circulation system of the process gas, thus allowing localized regulation both in terms of flow and temperature.

According to the system conceived, the gas, introduced at various points into the distribution chamber positioned below along the entire length of the base element, will ensure the heating of the polymer mass and consequently the removal of the by-products of the reaction (washing) from the surface of the granule, in extremely effective and uniform way.

The system thus conceived will allow to obtain an operating condition of production much more advantageous than that carried out in the prototypes used in laboratory tests, therefore with the possibility of reaching high reactivity values, equal to or higher than those consolidated in the laboratory tests itself. .

The average reactivity value that can be obtained will therefore be of the order of 0.030, against the typical values of current reactors ranging from 0.018, for the static vertical body reactor to 0.022 for the single horizontal rotating body reactor.

The higher reactivity value, with the same I.V. (Intrinsic Viscosity) initial and I.V. final, has repercussions in the following two possible advantages compared to current reactors:

1) with the same product in the “working capitai” reactor, a higher flow rate from 60% to 30% would be obtained respectively.

2) with the same flow rate, a quantity of product in the “working capitai” reactor would be obtained, respectively, lower from 60% to 30%.

The number, the dimensions and the section of the horizontal elements in series, see Table 3, can be studied according to the capacity of the system, in order to obtain space and construction costs in general.

By exploiting the typical characteristic of modular systems in parallel Tav 4, the presence of the bottleneck in the plant will then be avoided, with the further advantage of being able to increase the production capacity beyond the current maximum limits.

With this invention, a very useful advantage will also be obtained in the continuous industrial production of PET, by being able to carry out simultaneous processing of products with different degrees of viscosity on the various modules.

The basic elements see Table 1, which make up the modules, are extremely simple to build, therefore with limited weight and dimensions, such as to obtain considerable advantages, compared to current reactors, in terms of transport costs and assembly times. A further environmental improvement element is that in the reactor the connections of the basic elements to the product outlet supply ducts and to the process gas circulation circuit are provided with elastic joints, thus making it a sealed system with zero gas dispersion.

Furthermore, the operational characteristic of the low polymer bed on the gas diffusers means that the pressures of the process gas will be minbhmte compared to current technologies, therefore energy consumption and gas dispersions in the environment will consequently improve.

Claims (2)

High performance modular reactor for continuous polymerization of PET in the solid state. 1. Reactor made of elements in series and modules in parallel Each basic element includes: - a casing mounted on elastic supports and equipped with electric eccentric cam drives. - low molecular weight polymer feed line - process gas discharge line - plate gas diffuser placed in the lower part along the length of the base element. - gas supply lines in the gas distribution chamber. - discharge line for the polymerized product. Each module comprises one or more elements in series; the number is calculated to obtain the required degree of viscosity (I.V.) at the end of the series. The modules in parallel in number of two or more, allow to obtain the required product flow rate and the elimination of the bottleneck in the plant. 2. Reactor made according to claim 1, characterized in that the tubular element can have different geometric shapes, see Table 2. Modular reactor specific to use on the continuous upgrading plant of solid state PET. CLAIMING 1. The reactor invented consists of basic elements in series (tab 3) and modules in parallel (tab 4). Each basic element includes: - a shell installed on elastic supports, using electric activation by eccentric cams - inlet nozzle, to fill the low molecular weight polymer - process gas discharge line - a plate gas diffuser fixed on the bottom of the basic element along the working length. - inlet pipes to fill process gas in the diffuser chamber - outlet nozzle to discharge the up-graded polymer. Each module is made-up by one or more basic elements; the right number is valuated to have the required intrinsic viscosity I.V. on the product at outlet nozzle. The reactor is made-up with two or more parallel modules valuated to rich the required plant throughput. The parallel modules are enabling to avoid the bottle neck on the plant. 2. The build-up reactor according the claiming 1, but with additional remark that the basic element can have different geometric shapes (see tab 2).