Antifoulant dispersant

DESCRIPTION

ANTI DISPERSER — INCRUSTATION Fouling Dispersers

1. Field of the Invention

The present invention relates to an anti-dispersant. The present invention is particularly concerned with antifouling for use in centrifugal compressors used in compression in an ethylene based process.

2. state of art

Fouling on compressors is a well known problem in processes using compressors. Fouling of compressors can cause compressor damage as well as disruption to factory work, both potentially very costly problems. The industry has made a significant effort in preventing fouling. For example, US Patent No. 6,159,547 to McMordie, et al. Describes a method for covering turbo machinery with metal surfaces to prevent fouling. The method steps are to apply to the surface a viscous suspension containing, in acidic aqueous medium, an actively galvanized material and phosphate ions, thus forming a sacrificed first galvanized layer, to cure this first layer by applying to this first cured layer a second viscous solution, containing inorganic phosphate or silicate ions, curing this second layer, applying on this second cured layer a liquid sealant composition, containing a thermostable organic polymer and fluorocarbon, thereby forming an upper layer, which is then cured.

In some processes, the operating conditions to which compressors are subjected during operation may lead to scale and even erosion of compressor blades, regardless of how well the compressor blades may be covered. For example, US Patent No. 5,849,983 to Khatib discloses the addition of polyisobutylene to a predominantly gaseous stream to prevent fragmentation of hydrocarbon droplets into the stream to aerosol sizes. An advantage of this invention is that the application of polyisobutylene upstream of the compressor stations works to prevent scale and erosion of the compressor blades.

While a polymer may function in the prevention of scale, as described in US Patent No. 5,849,983 to Khatib, in some processes it is the formation of some polymers that can cause scale. For example, in a process involving ethylene, it is the formation of organic polymers that can cause fouling in the compressor.

US Patent Application Publication No. 2002/0020106 describes aminoalkylphenol emulsifiers used for the manufacture of aqueous hydrocarbon fuel emulsions suitable for use in engines.

Hydrocarbon vapor cracking is responsible for virtually all ethylene produced worldwide. Hydrocarbons used as ethylene feeders range from natural gas liquids including ethane, propane and butane to pre-oil liquids including oils and naphtha. In the ethylene production process, while ethylene is produced and purified, small amounts of polymers can be formed. These polymers are generally considered contaminants and are undesirable in the final product, ethylene. One point for the isolation of such contaminants is in compressors. Due to pressure changes, contaminants can be isolated as liquids and sent to vapor-liquid separation drums, where contaminants are kept until they are removed or sent for recycling.

3 Summary of the Invention

In one aspect, the present invention is a disperser prepared from a formulation consisting of: (a) the reaction product of a polyalkyl polyamine, an alkylphenol and an aldehyde; and (b) a polyalkyl acrylate polymer; wherein the two components are present in a weight ratio of 2: 0.5 to 2: 1.5.

In another aspect, the present invention is a method of preventing fouling on compressor blades used for compressing gases consisting of depositing a disperser on the blades of a compressor to be protected from fouling, wherein the disperser is prepared from a formulation. containing: (a) the reaction product of a polyamine polyamine, an alkylphenol and an aldehyde; and (b) a polyalkyl acrylate polymer; wherein the two components are present in a weight ratio of 2: 0.5 to 2: 1.5.

This type of disperser is desirable in the field of gas compression to prevent fouling on the compressor blades. It would be particularly desirable in the field of ethylene compression to prevent and prevent fouling on the compressor blades, while avoiding the creation of an emulsion in the vapor-liquid separation drums.

4 Description of Preferred Specifications

The present invention is on the one hand a method of preventing the scale of the compressor blades used to compress gases. The dispersants of the present invention function to prevent scale in the compressors by forming a film on the surface of the compressor blades that prevents, or at least reduces, the formation of polymers and other contaminants in the gases to be compressed.

In carrying out the procedure of the present invention, dispersants may be applied to compressor blades in any manner known to those of ordinary skill in the application of such materials that are useful in preventing scale. Preferably, the dispersers are applied as a spray aerosol to the compressor blades. More preferable is the injection of the dispersers into the gas stream to be compressed upstream of the compressor in the form of an aerosol which is then carried by the gas being compressed to the compressor blades. Particularly preferable is the fact that the disperser does not foam on the vapor-liquid separation drums, receivers of compressor material.

On the other hand, the present invention is a disperser prepared from a formulation containing at least two components. The first component of the disperser, termed Component A, is the reaction product of a polyamine polyamine, an alkylphenol and an aldehyde. Polyalkyl polyamines useful for the present invention have the general formula:

H₂n-ch ^ ch₂Xhn_ch ^ ch1nh₂* - - * n

Wherein n is an integer from 0 to 5. Exemplary amines include, but are not limited to, ethylenediamines and tetraethylenopenta amines, but any compound of general formula I may be used for the preparation of Component A of the present invention.

Alkylphenols useful for the preparation of Component A of the present invention have the general formula:

<img file="PT1556441E_D0001.tif" />

wherein R is an alkyl group of 1 to 120 carbons. Exemplary alkylphenols which may be used in the preparation of Component A according to the present invention include, but are not limited to, anisols, polybutylphenol and nonylphenol, but any alkylphenol of the general formula given above may be used. Aldehydes useful for the preparation of the first component of the present invention have the general formula:

O

Wherein R is an H or an alkyl group containing from 1 to 6 carbons. Preferably the aldehyde is formaldehyde.

Component A is the reaction product of a polyamine polyamine with an alkylphenol and an aldehyde. Component A is preferably a Mannich condensation product formed by the condensation of an alkylphenol of formula II with an aldehyde of formula III and a polyamine polyamine of formula I. The condensation reaction may be conducted at a temperature in the range of 40 ° C to 200 ° C. The reaction may be carried out crude (without diluent or solvent) or in a solvent or diluent. Water is involved and may be removed by azeotropic distillation during the course of the reaction. Aldehyde is typically present in a molar amount at least equal to the total molar amount of the amine compounds present. Component A may be prepared by any method which is familiar to persons of ordinary skill in the art useful for producing these reaction products.

Preferably, the Mannich condensate is a 1: 1 weight mixture of a first Mannich condensate prepared using a comparatively high molecular weight alkyl polyphenol and a second Mannich condensate which is prepared using a comparatively low molecular weight alkylphenol.

Any ratio of alkylphenol to aldehyde to polyalkyl polyamine which forms a stable reaction product may be used to prepare component A according to the present invention. Preferably, the weight ratio of alkylphenol to aldehyde is from 0.1: 1 to 60: 1. Preferably the weight ratio of aldehyde to polyalkyl polyamine is from 1: 1 to 6: 1.

The second component of the disperser according to the present invention is a polyalkyl acrylate polymer. For purposes of the present invention, the term acrylate polymers includes polymers containing repeated acrylate units, methacrylate units and mixtures thereof. The polymer is preferably a copolymer. These copolymers are typically prepared by first preparing an acrylic acid or methacrylic acid ester and a C1 -C10 alcohol and subsequently reacting the resulting ester with N-vinyl pyrrolidone or vinylpyridine. For example, VISCOPLEX® 6-917, available from RohMax, is a polyalkyl methacrylate polymer that can be used as component B in the present invention.

Although the use of copolymers is one of the preferred compositions, polyalkyl acrylate polymers are also useful as B components. For example, poly (isodecyl methacrylate) may be used as component B of the present invention. Other polymers having utility as component B according to the present invention include methacrylate), methacrylate), poly (nonyl acrylate), poly (butyl acrylate) and poly (tert-butyl poly (cyclohexyl poly (octadecyl methacrylate)).

Polyalkyl acrylate polymers and copolymers useful for the preparation of component B of the present invention are present in the disperser compositions according to the present invention in a Component A: Component B ratio of about 2: 1. This ratio refers to active polymer or polymer weight and not solution weight. For example, VISCOPLEX® 6-917 used in the examples is a 41% polymeric solution in a hydrocarbon solvent. Thus, a ratio of component A: Component B as proposed in Example 1 actually corresponds to an active polymer ratio of 10: 4.1 or 2: 0.82. The component A: component B ratio ranges from 2: 0.8 to 2: 1.2 and from 2: 0.9 to 2: 1.1 are the preferred ratios of component A: component B ratio in disperser compositions. of the present invention.

Although the two component formulation of the disperser of the present invention is effective in preventing undesirable polymer accumulation on the compressor blades, there is a second formulation of the disperser of the present invention which additionally has the desirable property of not creating emulsions with the concomitant foam. in vapor-liquid separation containers. While this formulation may not act on the destruction of existing emulsions, it does not itself form emulsions, unlike many other dispersers used to prevent unwanted polymer buildup on compressor blades.

In this second formulation, the ratio of component A to component B remains at about 2: 1, but component A is itself a mixture of two components, present in approximately equal amounts by weight, component A1 and component A2. Component A1 is a composition which is the reaction product of a polyamine polyamine, an alkylphenol and an aldehyde prepared using a comparatively high molecular weight alkylphenol. For example, component A1 may be prepared with a compound according to formula II wherein R is an alkyl group containing about 106 carbons. To prepare such an Al component, a polybutylphenol may be used, in which the polybutylphenol has 26 repeated butylene units. The molecular weight ratio of phenol to formaldehyde to amine of such component Al may be 60: 1: 3 while the molar ratio of phenol to formaldehyde to amine may be 2: 2: 1.

Component A2 may be characterized in that it is a composition which is the reaction product of a polyamine polyamine, an alkylphenol and an aldehyde prepared using a comparatively low molecular weight alkylphenol. For example, component A2 may be prepared with a compound according to formula II wherein R is an alkyl group of about 9 carbons. For the preparation of component A2 a nonylphenol may be used. The weight ratio of phenol to formaldehyde to amine for this A2 component may be 3.7: 1: 1 while the molar ratio of phenol to formaldehyde to amine may be 1: 2: 1.

Dispersers according to the present invention are preferably used as a hydrocarbon solution.

For example, the dispersers of the present invention may be added and mixed with kerosene, a heavy aromatic solvent, xylene, and the like prior to use to reduce viscosity and facilitate access of the disperser to compressor blades. Although the solution may have any concentration, the composition is preferably prepared and used in a solution with a percent dispersant in solvent of 70 to 90%, more preferably between 75 and 85% and preferably 80%.

Preferably, the dispersant of the present invention does not function as a hydrocarbon emulsifier.

Examples

The following examples are provided to illustrate the present invention. The examples are not intended to limit the scope of the present invention and should not be construed accordingly. Quantities are in parts by weight or weight percent, unless otherwise indicated.

Example 1

A disperser of the present invention is prepared by the addition and mixing of 5 parts condensate A1, 10 parts VISCOPLEX® 6-917, 5 parts condensate A2, and 80 parts kerosene. Condensate Al is a Mannich condensate of tetraethylenepentamine, a polybutylphenol with a molecular weight of about 1438, and formaldehyde. Condensate A2 is a Manich condensate of ethylenediamine, nonylphenol, and formaldehyde.

The ability of the disperser to disperse an ethylene gum in a non-solvent is tested. Contaminants from an ethylene compressor are isolated and dried to form a gum. A storage solution of this gum is prepared in xylene.

10mL of heptanes, a non-solvent for ethylene contaminants, is added to each of three 12.5mL centrifuge tubes. To each of these tubes is added 125pL of the storage solution. 0.15 ml of the 20 percent solution of the kerosene disperser is added to a tube. 0.75 ml of the 20 percent solution of the kerosene disperser is added to another tube. All tubes are shaken for 20 seconds and allowed to stand for 30 minutes. The tubes are reacted for 10 seconds and observed within one hour of the first stirring step.

The tube without disperser exhibits a flocculation to the 10mL mark on the scale marked laterally on the centrifuge tube. The tube to which 0.15mL of the disperser has been added exhibits a flocculation to the 3mL mark on the centrifuge tube scale. The tube to which 0.75mL of the disperser was added does not exhibit flocculation.

Example 2

A heat exchanger is used to test the ability of the disperser of the present invention to prevent fouling. A feed stream including diolofins,

ie, butadienes and pentadienes and dicyclopentadienes is supplied via a heat exchanger at 475^TheF (246 ° C). The dispersant solution of example 1 is added to the feed stream at a volume of 250ppm. Additional runs with lower and higher concentrations are also performed. The temperature of the feed stream at the protractor outlet is measured at the beginning of the experiment and again after 3 hours. The temperature differential is shown in the following table.

Table

<td>Scatter concentration</td><td>ΔΤ ²F (²Ç)</td><td>Fouling inhibition percentage</td>

<td>Without spreader</td><td> 30 (16,6)</td><td> —</td>

<td>25 ppm</td><td> 19 (10,6)</td><td> 37</td>

<td>250 ppm</td><td> 12 (6,7)</td><td> 60</td>

<td>500 ppm</td><td> 4 (2,2)</td><td> 87</td>

<td>1250 ppm</td><td> 3 (1,7)</td><td> 90</td>

Example 3

A 1: 1 mixture of kerosene and water is stirred to form an emulsion. Sufficient amount of Example 1 is added and mixed to form a mixture at 500 ppm with the water and kerosene mixture. It is observed that the emulsion disintegrates immediately.

Example 4

Example 1 is repeated and substantially substantially tested except that a further disperser prepared using a 41% solution of poly (isodecyl methacrylate) (CAS # 37200-12-7) in mineral oil is instead tested. VISCOPLEX® 6-917. The tube without addition of disperser solution exhibits flocculation to the 5mL mark and tubes containing both dispersors exhibit a flocculation of less than 1mL.

Example 5

Example 3 is substantially similarly repeated except that a second disperser is prepared using a 41% solution of poly (isodecyl methacrylate) (CAS # 37200-12-7) in mineral oil instead of VISCOPLEX® 6917. and is also tested. At a concentration of 500ppm disperser in the water and kerosene mixture no difference in behavior is observed between the VISCOPLEX® 6-917 disperser and the poly (isodecyl methacrylate) disperser. In each case there is rapid separation of the kerosene phase.

Example 6 Example 5 is repeated substantially identical except that the dispersers are present at a concentration of 250ppm and a second concentration of 100ppm. No difference is observed between the behavior of the VISCOPLEX® 6-917 disperser and the poly (isodecyl methacrylate) disperser. In each case there is a rapid separation of the aqueous phase and the kerosene phase.