JPS6361087A - Removal of metal from hydrocarbon supply raw material - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for deasphalting calcium-containing crude oils, heavy hydrocarbon residue oils, or solvents derived from crude oil or residue oils by using aminocarboxylic acids as sequestrants or chelating agents. Concerning a method for removing calcium from oil. A small but increasingly important group of crude oil feedstocks and residual oils contain levels of calcium that make them difficult, if not impossible, to process using conventional production techniques. Calcium contaminants that pose particular problems are non-porphyrinic compounds with organometallic bonds. This species has only recently been identified in crude oil, especially very heavy crude oil, and appears to be relatively rare. The calcium-containing contaminant compounds identified are calcium naphthenate and its congeners. These organocalcium compounds cannot be separated from the feedstock by conventional desalting methods and can cause very rapid deactivation of the hydrogenation catalyst in conventional purification techniques. An example of a feedstock containing undesirably high levels of calcium compounds is from the San Francisco Valley of California. Generally, this crude oil 5anJoaquin
Valley crude oil or residue oil is included in the pipeline mixture.

The problem posed by calcium in petroleum feedstocks and the need to solve it has only recently been recognized, and there is little literature in the prior art that specifically refers to the removal of calcium. However, metal removal using organometallics in general has been addressed in the prior art with particular reference to the removal of known metal contaminants such as nickel, vanadium and/or copper. These compounds are also commonly found in the feedstock in the form of porphyrins and other organometallic compounds.

In Lerner, US Pat. No. 3,052,627, a 2-pyrrolidone-alcohol mixture is used to remove metal contaminants from a crude oil feedstock.

In U.S. Pat. No. 3,167,500 to Payne, metal contaminants such as metal-containing porphyrins are removed from petroleum using a fused polycyclic aromatic compound having a favorable C/H ratio and molecular weight, commonly referred to as a pitch binder. removed. In U.S. Pat. No. 3,153,623 to Eldib et al., commercially available selections with high dielectric strength are used to promote electrically conducted precipitation for metal removal by polar organic molecules. organic compound is added.

It has now been unexpectedly discovered that calcium-containing contaminants can be efficiently removed from hydrocarbon feedstocks by binding calcium compounds using aminocarboxylic acids and their salts.

SUMMARY OF THE INVENTION The present process comprises the demetalization of hydrocarbon feedstocks, particularly crude oils or residual oils, using an aqueous solution of a chelating agent. This method is particularly suitable for removing calcium, especially non-porphyrin organically bound calcium compounds. Preferred metal chelating agents are amino-carboxylic acids such as nitrilotriacetic acid, N-(hydroxyethyl)ethylenediaminetriacetic acid and diethylenetri7minebentaacetic acid, salts thereof, or aqueous solutions of mixtures thereof.

In a preferred method, the feedstock to be demetallized is intimately and thoroughly mixed with the aminocarboxylic acid and its salts.

Since the resulting complex is water-soluble, the metal complexes with the chelating agent in the aqueous phase.

The aqueous and hydrocarbon phases are then separated to provide a hydrocarbon feedstock for hydroprocessing.

Various crude oil feedstocks and residual oils produced therefrom contain unacceptably high levels of calcium-containing contaminants. These calcium ions, especially those with organic bonds or calcium-containing compounds, usually pose significant difficulties in typical hydroprocessing techniques due to rapid deactivation or contamination of the hydroprocessing catalyst. The present invention consists of a method for removing the aforementioned calcium-containing contaminants prior to hydrogenation of crude oil or residual oil by using known chelating agents known as aminocarboxylic acids and their salts.

The present invention is applicable to hydrocarbon feedstocks containing calcium to unacceptably high levels.

This feedstock includes crude oil, especially San Joaque
Includes those from special sources such as ValleylQ oil (e.g. 5outh Belridge).
, to ern Front.

Cymric tleavySMidway 5uns
et, and Chinese Sheg Ii or mixtures thereof.

In addition, atmospheric or vacuum residue oils or solvent PA aspen oils derived from these crude oils and residue oils also contain unacceptably high levels of calcium. It is also within the contemplation of the present invention to process other hydrocarbon feedstocks using the present invention, such as shale oil, liquefied coal, upgraded sulfur sand, etc., which may contain calcium contaminants.

The basic process is relatively simple; the crude oil or residual oil to be treated is mixed with an aminocarboxylic acid, its salt or a mixture thereof and a base to adjust the pH to 2 or more and preferably from 5 to 9. Calcium does not easily bind to anions or chelates with anions to form complexes. This calcium/aminocarboxylic acid complex is ionic and therefore soluble in the aqueous phase of the mixture.

The two phases, the aqueous phase and the crude oil or hydrocarbon phase, are separated or allowed to separate.

Removal of the aqueous phase containing calcium contaminants yields a calcium-free hydrocarbon feed, which can then be handled like any carbonaceous feed and subjected to conventional hydroprocessing techniques. can be processed by In the present invention, it is contemplated that a physical separation step, typically carried out within the conventional crude oil debasing normally used to desalt crude oil prior to hydrotreating, is contemplated. However, separation can be performed by any conventional separation method,
Countercurrent extraction can also be used.

Aminocarboxylic acids have a high affinity for calcium and other metal ions. Common examples of aminocarboxylic acids known as chelating agents include dinitri-O-triacetic acid (NTA) (CHNo., molecular weight 191.1).
4,N,N-bis(carboxymethyl)glycine, also known as triglycolamic acid or triglycine): N-(hydroxyethyl)ethylenediaminetriacetic acid M (HEDTA) (CI01118N207, molecular weight 344.22, N-[ 2-[bis(carboxymethyl)
diethylenetriaminepentaacetic acid (DTPA) (C14H23N301°, molecular weight 393.35, pentedic acid, or N,N-bis[
(also known as 2-[bis(carboxymethyl)amino]ethyl]glycine); ethylenediaminetetraacetic acid W
i (EDTA) (C1oH16N208, molecule-
Amount 292.25, Nibutic acid, N,N'-1,2-ethanedylbis[N- (also known as carboxymethyl or Ilavidote).

Aminocarboxylic acids and their salts form a group of polydentate chelating ligands that complex or coordinate with metal ions. These compounds produce very stable metal-ligand complexes. Currently, EDTA is used as a sequestering agent to remove traces of metals, especially in laboratory analyses.

NTA and DTPA are used.

HEDTA is used as a laboratory sequestrant and also
A is also used as a builder for synthetic detergents. In particular, EDTA is used for the quantitative analysis of calcium and for purposes as a treatment agent against heavy metal poisoning and as a water softener in cleaning products.

These aminocarboxyl ligands form a complex with the ca+2 ion, which is stable and can be isolated. It is also water soluble, allowing its separation from the hydrophobic phase. Aminocarboxylic acids and their salts will also form complexes with other metal ions in aqueous solution;
such as nickel and vanadium petroleum porphyrins,
-m appears to have little or no effect on common organometallic metal contaminants commonly found in petroleum. However, it seems to have some effect on iron, so
Aminocarboxylic acids and their salts may be effective in removing organic iron compounds.

Aminocarboxylic acids in salt form can generally be produced in situ by the addition of a strong base, or in some cases isolated from aqueous solution as a crystalline salt. The salt is generally more water soluble and less acidic than the free acid.

As already mentioned, pt+ should be 2 or more, preferably 5 to 9, in order for calcium to properly bind to the aminocarboxylic acid. However, one difficulty with the addition of base is the formation of emulsions that can prevent efficient separation. Therefore, the most preferable p
H is about 6, which is especially true for naphthene M crude oils.

The ratio of aqueous aminocarboxylic acid solution to hydrocarbon feed should be optimized, the governing factor being the separation method. For example, commercial desalters typically operate with less than 10% aqueous volume.

Countercurrent extraction can also be used for separation, and efficient separation has been achieved at 50% or more aqueous volume when using this technique. The contact time between the aqueous extraction solution and the hydrocarbon feed can range from a few seconds to about 4 hours. The preferred contact time is about 4 to about 60 seconds. The temperature at which the extraction is carried out is also a factor in the efficiency of the process. The preferred temperature is 18
The temperature is preferably 0 or lower, and more preferably 300 or lower.

In laboratory tests, the results of which are detailed in Table 1 below, a certain type of mold, San Joaquin Valley vacuum residual oil (S
The residue -VR)(Ca 931)Dll) was dissolved in toluene to a manageable viscosity and mixed with the indicated EDTA solution, the preferred chelating or sequestering agent. This solution was prepared with appropriate skewers of EDT in deionized water to give a molar ratio of EDTA to calcium.
A was prepared by dissolving A and the pH of the solution was adjusted to about 9 with 1 cum of ammonium hydroxide.

A demulsifier having the trade name reatome L-1562 was added where indicated. ff1l EDTA/crude oil mixture
and allowed to separate, preferably overnight, at room temperature unless otherwise noted. The residual oil phase was analyzed before and after treatment to obtain the percentage calcium removal as indicated. Comparative examples using 10% hydrochloric acid solution, ammonium hydroxide solution and acidic water were also carried out and gave the results shown. Sheng, a Chinese crude oil containing a small but significant amount of calcium
Tests were conducted using l i crude oil as feedstock.

The results of each test are shown in Table 1 below.

Table 1 shows that for a good extraction on the order of 90% to 100%, only stoichiometric amounts of EDTA are required. For extractions carried out with acids, bases or water, the percentage calcium removal was extremely low.

Example 2 A laboratory test was carried out as in Example 1, except that ammonium hydroxide was used to adjust l)H to approximately 6. This pH is more suitable for crude oils with a high content of naphthenic acids. The results are shown in Table 2.

Removal of calcium by EDTA in Table 2 pt16 ED
TA/Ca EDTA (bond) Calcium
Aqueous phase pH molar ratio Residual oil (barrel)
Removal percentage Volume (%) 5.5 90
22.5 99 756.
0 16.5 4.06
99 336.4 6.9 1
．． 70 98 106.2
3 0.75 95
136.5 1 0.25
97 13 Example 3 Various aqueous to oil ratios were tried to determine the effect of aqueous phase volume on calcium removal.

The results are shown in Table 3.

Table 3 Aqueous 10 Calcium removal rate as a function of volume of aqueous phase
EDTA (mol) EDTA (bond)
Calcium volume (%) Calcium (mol)
Residual oil (barrel) removal percentage 66'
2.2 0.54 9933
16.5 4.06
9913 3 0
．． 74 9510 6.9
1.70 97.72
6.9 1.70
Another comparative study was conducted by using 1 to about 130 molar equivalents of EDTA to evaluate the removal of other metals from crude oil by 93.5 EDTA.

In this test, the removal percentages of iron, nickel, vanadium and magnesium were analyzed. The effect of EDTA on the removal of these other metals is shown in FIG.

Example 4 Other tests were performed similarly to the above to try other aminocarboxylic acids. The indicated parent San JOaQuin Valley vacuum retentate oil was dissolved in toluene, if necessary, to provide a manageable viscosity and mixed with the indicated aminocarboxylic acid solution at 10% by volume of the aqueous phase. The solution was prepared by dissolving the appropriate amount of amine carboxylic acid in deionized water to give 1.5 molar equivalents of chelating agent per mole of calcium, and adjusted to pH 6 with ammonium hydroxide. Adjusted to. A conventional demulsifier under the trade name Treatolite L-1562 was added. The mixture of aminocarboxylic acid solution and oil was separated by straining and standing at air temperature, preferably overnight. The residual oil was analyzed before and after treatment to determine the amount of calcium removed. Table 4 shows the results. EDTA was also included for comparison. Calcium removal by these chelators was excellent. That is,
The results of the determination were equal to the lower limit of the calcium determination technique. For comparison, Table 5 shows the
Figure 3 illustrates the removal of calcium from n Joaquin Valley vacuum retentate oil. These drugs have little calcium removal effect.

Table 4 Removal of Calcium from San Joaquin Valley Vacuum Residual Oil by Various Aminocarboxylates Chelating Agent 2J Lucium Removal Rate (
%) Ethylenediaminetetraacetic acid (EDTA) 99 Nitrilotriacetic acid (NTA) 93 N-(Hydroxyethyl) Ethylenediaminetriacetic acid (NEDTA) 94 Diethylenetriaminepentaacetic acid (DTPA) 94 Aqueous phase volume 10%, aqueous phase volume 10%, reaction time 1 minute , room temperature table 5! ! Acid 6.650 66 7.2 Ammonium hydroxide Large excess 66
9.2 Wed 200,000
160.2 Tests were conducted using 1 to 1.5 EDTA in 27% aqueous solution at various pHs to find the appropriate l)H level for this process. The treated feedstock was analyzed for various metals. The results are shown in Table 6 below.

Table 6 qdan Dandan Rainbow ■ 4.5 99 35 4 33.5
99 35 5 42.5 94 41
5 51.0 37 35 8
71 - 27% aqueous solution of 1.5 equivalents of EDTA

[Brief explanation of the drawing]

Figure 1 shows the effect of EDTA on other metals.

Claims (12)

[Claims] (1) A method for demetallizing a hydrocarbon feedstock comprising mixing the hydrocarbon feedstock with an aqueous solution of a sequestering agent; and separating a substantially demetalized hydrocarbon feedstock from the aqueous solution. (2) The method of claim 1, wherein the metal to be demetallized from the feedstock comprises a Group IIA metal. (3) The method according to claim 2, wherein the metal is calcium. (4) The method according to claim 1, wherein the metal is a non-porphyrin compound with an organometallic bond. (5) The method according to claim 4, wherein the compound is a calcium compound. (6) The method according to any one of claims 1, 2, and 4, wherein the sequestering agent comprises an aminocarboxylic acid, a salt thereof, or a mixture thereof. (7) The method of claim 6, wherein the sequestering agent is selected from the group consisting of NTA, HEDTA, DTPA, and EDTA, salts thereof, and mixtures thereof. (8) The method according to claim 7, wherein the sequestering agent is EDTA, a salt thereof, or a mixture thereof. (9) The method according to claim 1 or 6, wherein the pH in the mixing step is adjusted to 2 or more. (10) The method according to claim 1 or 6, wherein the pH in the mixing step is adjusted to 5 or more. 11. The method of claim 1, wherein the separation is carried out by a method selected from the group consisting of conventional crude oil desalination methods and countercurrent extraction. (12) the hydrocarbon feedstock is selected from the group consisting of crude oils, atmospheric or vacuum residue oils, solvent deasphalted oils derived from these crude oils and residue oils, shale oils, liquefied coal, and tar sands effluents; A method according to claim 1.