Patent Grant
7204927
The present invention relates to treatments for accelerating settling of solids in hydrocarbon fluids. The treatments of the present invention are particularly effective at accelerating the settling of FCC catalyst fines in an oil slurry.
Unrefined hydrocarbons such as crude oil, resids and bottom streams often contain finely divided solid matter, which often must be removed 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 also 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 slurry containing 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 accelerate the separation process. Both native and synthetic components of the slurry oil have a dispersant effect which retards the settling of the fines.
The present inventor has discovered that a combination of certain chemical agents, when added to the slurry oil, have an anti-dispersant or coagulant effect which accerlates 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.
The present invention relates to compositions and methods for accelerating the settling of finely divided solids in hydrocarbon fluids, the methods comprising adding to said hydrocarbons an effective settling amount of a combination of at least two of (a) a quaternary fatty ammonium compound, (b) a hetero-atom punctuated fatty polymer and (c) an alkylphenol-formaldehyde resin alkoxylate.
The quaternary fatty ammonium compounds are generally quaternary ammonium compounds having the formula:
where R1, R2, R3 and R4 can be —R5—, —(R5O)m—, or
where R5, R6, R7 and R8 can be C1 to C30 alkylene, alkenylene, or alkylarylidene, and m is 1–25, X is a halide, sulfate, nitrate, phosphate or carboxylate anion, and n is 1–50.
The particular quaternary fatty ammonium compounds of the present invention are effective at accelerating settling of finely divided solids, particularly FCC catalyst fines. These compounds include, but are not limited to methyl quaternary amine ethoxylates such as tallow triethoxyl quaternary amine acetate and a hydrogenated C18 methyl chloride quaternary amine with 15 moles ethylene oxide, as described in U.S. Pat. No. 5,476,988, herein incorporated by reference.
By “hetero-atom punctuated fatty polymers” it is meant a polymer of MW 103 to 106 in which C10–C30 alkyl or alkenyl “fatty” hydrocarbon groups are separated in some way (i.e., punctuated) by hetero-atom (non-C,H) containing groups such as ethers, esters, amides, amines, phenols, heterocycles, thio and halo carbons, and the like, which are smaller in size than the fatty groups. Additional details regarding these particular compounds are found in U.S. Pat. No. 5,593,572, also herein incorporated by reference.
As to the alkylphenol-formaldehyde resin alkoxylate component of the present invention, such materials generally have molecular weights in the range of from about 500 to about 5,000, with a range of about 1,000 to about 2,500 preferred. The alkyl group may be linear or branched, and have from about 1 to about 24 carbon atoms, with a range of from about 4 to about 9 preferred. The alkoxy group has about 2 to about 4 carbon atoms, with 2 preferred; the alkoxylation comprises about 20 to 80 percent by weight of the molecule, with about 50 percent preferred. Additional details regarding this component of the present invention are found in U.S. Pat. No. 5,681,451, also herein incorporated by reference.
The present invention relates to a chemical treatment to settle solids in a liquid matrix. The liquid matrix may be either organic, or a mix of organic and aqueous matrices. The chemicals used to settle solids are a combination of at least two of the following materials: quaternary ammonium chemicals, vinyl acetate copolymers and alkylphenol formaldehyde chemicals.
In the testing of the present invention, solids settling efficiency was determined by bottle testing. The process fluid was heated before mixing; after appropriate mixing to homogenize the fluid, 100 ml was poured into 150 ml glass bottles. Approximately 20 percent total raw materials in highly aromatic naptha (HAN) comprised the starting spiking solution. Cosolvents that may be used include up to 10 percent of the following: kerosene, heptane, n-butanol, hexylene glycol, and/or xylene. Table 1 shows a preferred composition of various materials of the present invention, each as 20 percent total raw material blend.
1Ethoquad ® 18/25: PEG-15 stearmonium chloride
2Ethoquad ® T/13-50: Tris (2-hydroxyethyl) tallowalkyl ammonium acetate
3Elvax ® 210: Ethylene/vinyl acetate copolymer
4Paraflow 185: Dialkyl fumurate/vinyl acetate copolymer
5Baker 7935: Alkoxylated alkylphenol formaldehyde
In the further testing of the present invention, as shown in Table 2 below, a blank and a control were tested in each run. The blank had no added solvent or additive. The control sample was dosed with the appropriate amount of the solvent, in order to mimic solvent addition in additized tested fluids. The samples were mixed by an automatic shaker; after mixing was complete, the samples were placed into a hot bath for a determined amount of time. After this predetermined residence time in the hot bath, the samples had the top 50% of the particular sample withdrawn and filtered. The bottom portion was then filtered, and the container rinsed out with appropriate solvent. The filter papers were then placed in a furnace at 900° F. for approximately 9 hours.
As shown below, the results of the testing were recorded as percents settling from the following formula: [bottom ash (b)−top ash (t)]÷[bottom ash (b)+top ash (t)]. The results demonstrated the efficacy of the treatment of the present invention.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5476988 | Hart et al. | Dec 1995 | A |
| 5593572 | Hart | Jan 1997 | A |
| 5681451 | Hart | Oct 1997 | A |
| Number | Date | Country | |
|---|---|---|---|
| 20040089590 A1 | May 2004 | US |
