WO1997004042A1

WO1997004042A1 - Settling aids for solids in hydrocarbons

Info

Publication number: WO1997004042A1
Application number: PCT/US1996/009354
Authority: WO
Inventors: Paul R. Hart
Original assignee: Betzdearborn, Inc.
Priority date: 1995-07-20
Filing date: 1996-06-07
Publication date: 1997-02-06

Abstract

Disclosed are methods for accelerating the settling of finely divided oil and water insoluble solids in hydrocarbon fluids using an effective amount of an alkylphenol ethoxylate compound. Preferably, the hydrocarbon is a fluid catalytic cracker slurry containing spent catalyst fines.

Description

SETTLING AIDS FOR SOLIDS IN HYDROCARBONS

TECHNICAL FIELD

The present invention relates to methods for accelerating settling of solids in hydrocarbon fluids. The methods of the present invention are particularly efficacious at accelerating the settling of FCC catalyst fines in an oil slurry.

BACKGROUND ART

Unrefined hydrocarbons such as crude oil, resids and bottom streams often contain finely divided solid matter which often must be re- moved prior to further use or processing. These solids can include solids of a soil-like nature, finely divided silicas, clays, silt and coke, and metal oxide and sulfide corrosion solids. These solids may include traces of metal particles such as lead, nickel, chromium and the like, and salts thereof.

For instance, fluid catalytic cracker (FCC) units use a fluidized bed of zeolite type aluminosilicate clay particles to crack heavy petroleum fractions into lighter fractions at elevated temperatures. The catalyst is eventually deactivated by poisoning or coking. These spent fines must be removed from the FCC on a continual basis so that fresh catalyst can be added. Some of this slurry oil containing the spent fines is then typically settled in tankage, though hydrocyclones are sometimes used to accel¬ erate the separation process. Both native and synthetic components of the slurry oil have a dispersant effect which retards the settling of the fines.

U.S. Pat. No. 4,539,099 describes a method to enhance the grav¬ ity settling rate of suspended solids from hydrocarbon oil by the addition of an oxyalkylated phenol formaldehyde resin glycol ester.

U.S. Pat. No. 4,407,707 discloses a method of removing particulate solids from hydrocarbon oil by adding to the oil an alkoxylated sorbitan fatty ester (optionally with an organo sulfonic acid or salt and/or a demul¬ sifier), then washing the solids out of the oil with 5-50% water. The solids are not settled from the oil in any way but are transferred to water and settled from the water. The use of water to wash the solids, though effec¬ tive here, involves processing difficulties which precludes its use, and which we avoid in our settling method. U.S. Pat. No. 2,952,620 describes a process for removing solids from hydrocarbon oil by washing the oil with water containing a nonionic surfactant. Any nonionic surfactant which works with this water washing method is said to work, including alkylphe¬ nol ethoxylates. There is no hint or suggestion of such surfactants, which would implicitly include those of U.S. Pat. Nos. 4,407,707 and 4,539,099, having an effect in the absence of water washing or what that effect might be. U.S. Pat. No. 4,889,618 discloses a process for removing solids from hydrocarbon oil by washing the oil with water containing concentrated caustic. The present inventor has discovered that certain chemical agents, when added to the slurry oil, have an anti-dispersant or coagulant effect which accelerates the settling process. This produces a cleaner decant oil (typically <0.05 wt % ash) in a shorter period of time and can then be sold as carbon black feedstock or residual fuel oil.

DISCLOSURE OF THE INVENTION

The present invention relates to methods for accelerating the settling of finely divided oil and water insoluble solids in hydrocarbon fluids com¬ prising adding to the hydrocarbon an alkylphenol ethoxylate compound. More particularly, the present invention provides methods for accelerating the settling of spent fluid catalytic cracker (FCC) catalyst fines in an oil slurry comprising adding an alkylphenol ethoxylate to the oil slurry.

The alkylphenol ethoxylate compounds that are useful in the methods of the present invention generally have an alkyl chain length of about 4 carbons to about 20 carbons with about 9 carbons preferred. These compounds also possess a degree of ethoxylation which ranges from about 1 mole ethylene oxide (EO) to about 40 moles EO, with 5 to 10 moles preferred.

The particular alkylphenol ethoxylate compounds useful in the pre¬ sent invention will be effective at accelerating the settling of finely divided oil and water insoluble solids, particularly FCC catalyst fines. The preferred alkylphenol ethoxylate compounds have Iower ethoxylation values and are more oil soluble. Examples of these compounds include but are not limited to nonylphenol ethoxylates having 5 and 9.5 moles of ethoxylation respec¬ tively. These compounds are commercially available as Igepal CO-520 from GAF and Surfonic N-95 from Texaco, respectively.

Actual dosage ranges for the alkylphenol ethoxylate compounds de¬ pend upon the characteristics of the hydrocarbons to be treated. These characteristics can vary and include the type of hydrocarbon, the type and amount of finely divided solid present, the oil and water solubility of the finely divided solids, and the presence of other impurities and surfactants in the hydrocarbon fluid. For the purposes of this invention, the term "ef¬ fective amount" refers to the amount of alkylphenol ethoxylate compound necessary to accomplish the purpose of the treatment. The effective amount will generally range from about 5 to about 500 parts per million parts of hydrocarbon with a range of from about 25 to about 100 parts per million parts of hydrocarbon preferred.

The alkylphenol ethoxylate compounds can be fed to the hydrocar¬ bon to be treated neat or in a suitable solvent that is compatible with the treatment and the hydrocarbon. Examples of such solvents include but are not limited to petroleum distillates, aromatic naphthas, mineral oils, alkyl ethers, esters and alcohols.

MODES FOR CARRYING OUT THE INVENTION

The following examples are intended to show the efficacy of the present invention as an accelerator for settling finely divided oil and water insoluble solids in hydrocarbons and should not be construed as limiting the scope of the invention. Examples

Catalyst Settling Aid Test.

This test measures the fraction of FCC catalyst fines which settle to the bottom of a slurry sample compared to the amount which remains dispersed on top. This test simulates slurry settling in tankage between ambient temperature and 200°F.

Experimental

Collect 100 mL of FCCU slurry in 6 oz. bottles. Place bottles in a water bath and heat to process temperature. Remove each bottle from the bath and add the appropriate treatment to the desired bottles. Place the bottles in an insulated shaker and shake on high speed setting for 10 minutes. Retum the bottles to the bath and allow to stand undisturbed for the predetermined settling period. This predetermined settling time for a blank is determined by analyzing several untreated bottles according to this test procedure at various time intervals centered on the tank's resi- dence time (e.g., 5 hours, 1 day, 3 days, 7 days).

Test methods vary in the point at which the sample is split between the top and the bottom portions for analysis at the end of the settling period. The size of the top portion is used to designate the method used.

For most samples, the "50% method" described below is used. For extremely fast settling samples, a short settling time and the "95% method" described below is used. For very slow settling samples, a long settling time and the 20% or 10% variation of the 50% method is used. 50% method (or 20% or 10%)

Pipet off the top 50 mLs (or 20% or 10%) with a syringe being careful not to disturb the sample or insert the needle below the 50 (or 80 or 90) mL line, and transfer to a clean bottle. This is the "top" sample. The original bottle contains the "bottom" sample.

95% method

Pour off ~95 mLs (i.e. what will easily pour) into a clean bottle. This is the "top" sample. The remaining ~5 mLs in the original bottle is the "bottom" sample.

Place filter pads in small petri dishes, dry uncovered at 220°F for one hour, remove from oven and allow to cool in a desiccator.

Shake the oil sample vigorously and carefully pour it, up to 50 mL at a time, into a graduated 100 mL centrifuge tube, then double the vol¬ ume, up to 100 mL, with xylene or toluene. Heat the centrifuge tube to 180°F in a water bath. Centrifuge for 15 minutes.

Weigh and record filter weight. Place filter in a paraboloid filtration funnel and wet with xylene or toluene to ensure a good seal for vacuum filtration. Turn on the vacuum pump and pour a small amount of hot oil from the centrifuge tube into the filter funnel and allow it to filter. Rinse with xylene or toluene. Continue adding small amounts and rinsing until all the sample has been filtered. Then rinse centrifuge tube and funnel with more xylene or toluene until they are clean. Remove filter bowl and wash, under vacuum, the filter pad with xylene or toluene followed by petroleum ether or heptane. Dry filter pad in an oven at 220°F for one hour. Allow to cool in a desiccator and reweigh.

Place the filters in glass petri dishes and ash in a muffle fumace at ~900°F. Weigh again to determine catalyst weights, being careful not to disturb loose ash on filters.

The % settled is calculated by the following methods:

20% method : % settled = bottom - 4 x top (q) bottom + top (g)

50% method : % settled = bottom - top (g) bottom + top (g)

95% method : % settled = bottom - top/19 (q) bottom + top (g)

A settling period which yields about 40 to 50% settled should be chosen. Repeat the optimal procedure, determined from the blanks, after adding chemical treatments at the process dosage.

Testing was performed utilizing the compounds of the instant invention and commercially available chemicals known to be used as FCC catalyst settling aids, or of a similar type, including the best known performing nonylphenol-formaldehyde resin ethoxylate. TABLE I

Slurry settling study

Various refineries

75 ppm active treatment added

% Ash Settled

Southern Refinery Northeast Refinery Western Refinery

Settled 14 days @ Settled 6 days @ Settled 14 days @

170°F 170°F 70°F

Treatment 50% Method 50% Method 95% Method

A 56 74.7 91.0

B 36 82.4 89.4

Comp 1 -17* 65.0 97.8

Blank 21 71.7 91.8

^•Bottom removed instead of top.

Treatment A is a nonylphenol ethoxylate with 5 moles ethylene oxide. Treatment B is a nonylphenol ethoxylate with 9.5 moles ethylene oxide. Comp 1 is a commercially available nonylphenol-formaldehyde ethoxylate.

These results demonstrate that the alkylphenol ethoxylate com- pounds in accordance with the present invention effectively accelerate the settling of finely divided solids in hydrocarbons from different refineries.

Further testing was performed on an FCCU catalyst slurry and is reported in Table II. TABLE II

Southern Refinery

FCCU catalyst slurry settling study

1 day settling time at 160°F

50 and 95% methods

% Settled % Settled

Treatment 130-140 total volume > from top from top weight ash in mg 50% to 96% to

(DDm) 70 mL top) 55-65 (mid) 5 mL (bot) Bottom 50% Bottom 4%

A (62.5) 47.3 36.4 75.4 41 44

44.7 28.0 66.2 36 45

Comp 1 (75) 47.9 38.8 151.8* 60* 62^*

45.8 25.1 69.6 35 47

Blank 47.5 37.2 87.0 45 49

45.5 36.8 85.0 46 49 ^*Probable chunk in bottle which fell to the bottom.

Treatment A is a nonylphenol ethoxylate with 5 moles ethylene oxide. Comp 1 is a commercially available nonylphenol-formaldehyde ethoxylate.

These results demonstrate that the alkylphenol ethoxylate com¬ pounds of the present invention are not always effective but are no less effective at settling the slurry as an alternative compound. TABLE III

Midwestern refinery Slurry settling study 24 hours settling time at 200°F 95% method

Filterable Solids

Top Top Bot 5% Bot 5% % Settled

Treatment Total wt 95% wt 95% wt wt wt (B-T/19) (ppm) used ( α ) ( q ) (% solids) ( q ) (% solids) (B + T)

Blank 0.2410 0.1868 77.50 0.0542 22.5 18

A (25) 0.6346 0.1750 27.60 0.4596 72.40 71

Comp 1 0.2550 0.2007 78.70 0.0543 21.30 17 (30)

Comp 2 0.2277 0.1758 77.20 0.0519 22.80 19 (30)

TABLE IV

Midwest refinery

Slurry settling study

24 hours settling time at 200°F

95% method

Ash

Top Top Bot 5% Bot 5% % Settled

Treatment Total wt 95% wt 95% wt wt wt (B-T/19)

(ppm) used ( q ) ( q ) (% solids) ( α ) ι (% solids) (B + T)

Blank 0.2269 0.1780 78.40 0.0489 21.60 17

A (25) 0.5918 0.1654 27.90 0.4264 72.10 71

Comp 1 0.2397 0.1904 79.40 0.0493 20.60 16

(30)

Comp 2 0.2139 0.1671 78.10 0.0468 21.90 18

(30) Treatment A is a nonylphenol ethoxylate with 5 moles ethylene oxide. Comp 1 is a commercially available nonylphenol-formaldehyde ethoxylate.

Comp 2 is a commercially available catalyst settling aid, Exxon Corexit 115, thought to be an alkylphenol-formaldehyde alkoxylate or its ester (U.S. Pat. No. 4,539,099).

As demonstrated in Tables III and IV, alkylphenol ethoxylate com- pounds in accordance with the present invention proved more effective at settling both filterable solids and ash than an altemate compound and the conventional settling aid.

Further studies were conducted utilizing the alkylphenol ethoxylate compounds to settle filterable solids and ash in an FCC catalyst slurry. These results are reported in Tables V and VI.

TABLE V

Midwestern refinery Slurry settling study

24 hours settling time at 200°F 95% method

Filterable Solids

Top Top Bot 5% Bot 5% % Settled

Treatment Total wt 95% wt 95% wt wt wt (B-T/19)

(ppm) used ( α ) ( q ) (% solids) ( a ) i [% solids) (B + T)

Blank 0.2021 0.1654 81.80 0.0367 18.20 14

A (62.5) 0.2214 0.1716 77.50 0.0498 22.50 18

Comp 1 0.2038 0.1520 74.60 0.0518 25.40 21

(75)

Comp 2 0.2093 0.1165 55.70 0.0928 44.30 41

(75) TABLE VI

Midwest refinery

Slurry settling study

24 hours settling time at 200°F

95% method

Ash

Top Top Bot 5% Bot 5% % Settled

Treatment Total wt 95% wt 95% wt wt wt (B-T/19)

(ppm) used ( α ) ( α ) (% solids) ( α ) (% solids) (B + T) Blank 0.1896 0.1569 82.80 0.0327 17.20 13

A (62.5) 0.2085 0.1633 78.30 0.0452 21.70 18

Comp l 0.1924 0.1447 75.20 0.0477 24.80 21 (75)

Comp 2 0.1966 0.1111 56.50 0.0855 43.50 41 (75)

Treatment A is a nonylphenol ethoxylate with 5 moles ethylene oxide. Comp 1 is a commercially available nonylphenol-formaldehyde ethoxylate. Comp 2 is a commercially available catalyst settling aid, Exxon Corexit 115, thought to be an alkylphenol-formaldehyde alkoxylate ester.

These results demonstrate that the compounds in accordance with the invention were effective in settling solids from an FCC slurry. These compounds also proved comparable to higher dosages of one of an alter¬ nate compound, though inferior to the conventional settling aid in this fluid. TABLE VII

Southem refinery

FCC slurry settling study

20 hours settling time at 160°F

10% methods - solids

Treatment Wt. in top 10 mL Avg. Wt. Weight of Avg. Wt.

(ppm) after 20 hours (α) (q) sample (α) Wt.% % in too

Blank 0.019 0.022 10.71 0.177 0.233

Blank 0.025 10.71 0.233

Comp 1 (75) 0.012 0.010 10.92 0.110 0.093

Comp 1 (75) 0.008 10.52 0.076

Comp 1 (150) 0.009 0.011 10.24 0.088 0.088

Comp 1 (150) 0.013 broken

Comp 1 (225) 0.008 0.010 11.01 0.073 0.086

Comp 1 (225) 0.011 10.97 0.100

A (62.5) 0.016 0.016 10.64 0.150 0.150

A (125) 0.020 0.020 10.80 0.185 0.185

A (187.5) 0.017 0.017 10.88 0.156 0.156

On this fluid the inventive compounds were effective but inferior to the first altemate compound.

The alkylphenol ethoxylate compounds prove effective in a variety of hydrocarbon fluids. These hydrocarbon fluids are generally unrefined hydrocarbons that are prone to containing finely divided oil and water in¬ soluble solids. These hydrocarbon fluids include but are not limited to crude oils and fractions or residuals of crude oils boiling over about 400°F. While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modi¬ fications of this invention will be obvious to those skilled in the art. The appended claims and this invention generally should be construed to cover all such obvious forms and modifications which are within the true scope of the present invention.

Claims

Having thus described the invention, what I claim is:

1. A method for accelerating the settling of finely divided oil insoluble and water insoluble solids in hydrocarbon fluids comprising adding to the hydrocarbon fluids an effective amount of an alkylphenol ethoxylate compound or mixtures thereof.

2. The method as claimed in claim 1 characterized in that the alkylphenol ethoxylate compound has an alkyl length of from about 4 carbons to about 20 carbons.

3. The method as claimed in claim 1 or 2 characterized in that the alkylphenol ethoxylate compound has a degree of ethoxylation ranging from about 1 mole EO to about 40 moles EO.

4. The method as claimed in any one of the preceding claims characterized in that the alkylphenol ethoxylate compound is selected from the group consisting of nonylphenol ethoxylate with 5 moles ethyl¬ ene oxide and nonylphenol ethoxylate with 9.5 moles ethylene oxide.

5. The method as claimed in any one of the preceding claims characterized in that the hydrocarbon is a fluid catalytic cracker catalyst slurry.

6. The method as claimed in any one of the preceding claims characterized in that the finely divided oil insoluble and water insoluble solids are fluid catalytic cracker catalyst fines.

7. The method as claimed in any one of the preceding claims characterized in that the hydrocarbon fluid is selected from the group consisting of crude oils and fractions or residuals of crude oils having boiling points over 400°F.

8. The method as claimed in any one of the preceding claims characterized in that the alkylphenol ethoxylate is added to said hydro¬ carbon fluid in an amount ranging from about 5 parts to about 500 parts per million parts of hydrocarbon fluid.