JPH0470353B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for removing calcium from calcium-containing crude oils, heavy hydrocarbon residue oils, or solvent deasphalted oils derived from crude oil or residue oils by using aminocarboxylic acids as sequestrants or chelating agents. 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 are not separated from the feedstock by conventional desalting methods and can cause very rapid deactivation of the hydroprocessing catalyst in conventional purification techniques. An example of a feedstock containing undesirably high levels of calcium compounds is from the San Joaquin Valley of California. Generally, this crude San
Found in pipeline mixtures called Joaquin Valley crude oil or residual oil. 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 addresses the removal of calcium. However, metal removal using organic metals generally
The prior art deals specifically with 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 U.S. Pat. No. 3,052,627, 2
- Metal contaminants are removed from a crude oil feed using a pyrrolidone-alcohol mixture. In U.S. Pat. No. 3,167,500 to Payne, metal contaminants such as metal-containing porphyrins are removed from petroleum oil using fused polycyclic aromatic compounds having favorable C/H ratios and molecular weights, commonly referred to as pitch binders. In U.S. Pat. No. 3,153,623 to Eldib et al.
Selected commercially available organic compounds with high inductive strength are added to facilitate the electrically carried out precipitation to remove metals by polar organic molecules. It has 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 chelators are nitrilotriacetic acid, N-(hydroxyethyl)
Amino-carboxylic acids such as ethylenediaminetriacetic acid and diethylenetriaminepentaacetic acid, aqueous solutions of their salts or 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
May include those from special sources such as Joaquim Valley crude oil, South Belridge,
Kern Front, Cymric Heavy, Midway
Sunset, and Chinese Shegli or mixtures thereof may be included. In addition, atmospheric or vacuum residue oils or solvent deasphalted 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 tar sands, 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, a salt thereof 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 other 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 abasification normally used to desalt crude oil prior to hydrotreating, is contemplated. However, separation can be carried out by any conventional separation method, and 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: nitrilotriacetic acid (NTA) ( _C6
H ₉ NO ₆ , molecular weight 191.14, N,N-bis(carboxymethyl)glycine, also known as triglycolamic acid or triglycine); N-(hydroxyethyl)ethylenediaminetriacetic acid (HEDTA) (C ₁₀ H ₁₈ N ₂ O ₇ , molecular weight 344.22, N-
[2-[bis(carboxymethyl)amino]-ethyl]-N-(2- _hydroxyethyl )glycine); also known as diethylenetriaminepentaacetic acid (DTPA) ( _C14H23N3O10 , molecular _{weight 393.35} , pentetine ethylenediaminetetraacetic acid (EDTA ₎ ( _C10H16N2O8 , molecular _{weight 292.25} , edetic acid, N,N'-1,2-ethanedylbis[N
- (carboxymethyl)glycine] or also known as Havidote). 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 trace metals, especially in laboratory analyses.
NTA and DTPA are used. HEDTA
is used as a laboratory sequestering agent, and NTA is also used as a builder in 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 complexes with Ca ⁺² ions, which are stable and can be isolated. It is also water soluble and
allowing its separation from the hydrophobic phase. Aminocarboxylic acids and their salts may also complex with other metal ions in aqueous solution, but are more commonly found in common organometallic metal contaminants in petroleum, such as nickel and vanadium petroleum porphyrins. appears to have little or no effect on However, since they appear to have some effect on iron, aminocarboxylic acids and their salts may be effective in removing organic iron compounds. Aminocarboxylic acids in salt form can generally be generated in situ by addition of almost any strong base, and 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 mentioned above, in order for calcium to properly bind to aminocarboxylic acids, the pH must be 2.
The number should preferably be between 5 and 9. However, one difficulty with the addition of base is the formation of emulsions that can prevent efficient separation. Therefore, the most preferred PH is about 6, especially for naphthenic 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 have an aqueous volume of
Drive at 10% or less. 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. Preferred contact times are from 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. A preferred temperature is 180° or higher, and a more preferred temperature is 300° or higher. EXAMPLE 1 In a laboratory test, the results of which are detailed in Table 1 below, a certain amount of San
Joaquin Valley Vacuum Residual Oil (SJV-VR) (Ca
(93 ppm) was dissolved in toluene to a manageable viscosity and mixed with the indicated amount of EDTA solution, the preferred chelating or sequestering agent.
This solution contains the appropriate amount of EDTA in deionized water to give the molar ratio of EDTA to calcium.
The pH of the solution was adjusted to about 9 with ammonium hydroxide. Trade name
Treatolite L-1562 demulsifier was added where indicated. The EDTA/crude oil mixture was shaken 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 with the results shown. The tests were conducted using Shengli crude oil, a Chinese crude oil that contains a small but significant amount of calcium, as a feedstock. The results of each test are shown below.
Shown in the table.

Table 1 shows that a nearly stoichiometric amount of EDTA is required for a good extraction of 90% to 100%. In the case of extractions carried out with acids, bases or water, the percentage calcium removal was very low. Example 2 A laboratory test was carried out as in Example 1, except that the pH was adjusted to about 6 using ammonium hydroxide. This PH is more suitable for crude oils with high naphthenic acid content. The results are shown in Table 2.

Table: 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: 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 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 amount of San Joaquin Valley vacuum retentate oil was dissolved in toluene, if necessary, to give a workable viscosity and mixed with the indicated aminocarboxylic acid solution to give a 10% by volume aqueous phase. The solution was prepared by dissolving the appropriate amount of aminocarboxylic acid in deionized water to give 1.5 molar equivalents of chelating agent per mole of calcium, and the pH was adjusted to 6 with ammonium hydroxide. Adjusted to. Trade name
A conventional demulsifier of Treatolite L-1562 was added. The mixture of aminocarboxylic acid solution and oil was shaken and allowed to stand at room temperature, preferably overnight, to separate. 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 quantitative results were equal to the lower limit of the calcium quantitative technique. For comparison, Table 5 shows the removal of calcium from San Joaquin Valley vacuum retentate oil by conventional desalting solutions. These drugs have little calcium removal effect. Table 4 Removal of Calcium from San Joaquin Valley Vacuum Residual Oil by Various Aminocarboxylates Chelating Agents Calcium Removal (%) Ethylenediaminetetraacetic acid (EDTA) 99 Nitrilotriacetic acid (NTA) 93 N-(Hydroxyethyl) Ethylenediaminetriacetic acid Acetic acid (NEDTA) 94 Diethylenetriaminepentaacetic acid (DTPA) 94 Chelating agent (mol)/Calcium (mol) = 1.5, PH
= 6, aqueous phase volume 10%, aqueous phase volume 10%, reaction time 1
minutes, room temperature

[Table] Ammonium water 200000 16 0.2

1 to 1.5 equivalents in a 27% aqueous solution of various PH to find the appropriate PH level for this process.
Tests were conducted using EDTA. The treated feedstock was analyzed for various metals. The results are shown in section 6 below.
Shown in the table.

【table】 [Brief explanation of the drawing]

Figure 1 shows the effect of EDTA on other metals.

Claims (1)

[Scope of Claims] 1 selected from the group consisting of crude oil, atmospheric or vacuum residue oil, solvent deasphalted oil derived from these crude oils and residue oils, shale oil, liquefied coal, and tar sands spill oil; a hydrocarbon feedstock comprising a non-porphyrinic compound in which a Group A metal is organometallic bound to an aqueous solution of a sequestering agent comprising an aminocarboxylic acid, a salt thereof, or a mixture thereof; and a substantially demetalized hydrocarbon feedstock. separating a feedstock from this aqueous solution selected from the group consisting of crude oil, atmospheric or vacuum residue oils, solvent deasphalted oils derived from these crude oils and residue oils, shale oils, liquefied coal, and tar sands spill oils. A process for demetallizing a hydrocarbon feedstock containing a non-porphyrinic compound in which a Group A metal is organometallic bound. 2. The method according to claim 1, wherein the Group A metal is calcium. 3. The method of claim 1, wherein the sequestering agent is selected from the group consisting of NTR, HEDTA, DTPA, and EDTA, salts thereof, and mixtures thereof. 4. The method according to claim 3, wherein the sequestering agent is EDTA, a salt thereof, or a mixture thereof. 5. The method according to claim 1 or 2, wherein the PH in the mixing step is adjusted to 2 or more. 6. The method according to claim 1 or 2, wherein the pH of the mixing step is adjusted to 5 or higher. 7. 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.