Patent Application
20250043201
This patent application claims priority under 35 U.S.C. Section 119 to Mexican Patent Application No. MX/a/2023/009023, filed Jul. 31, 2023, the entire disclosure of which is incorporated herein by reference.
The object of the present disclosure is to provide a process for producing alkylation gasoline using a batch-type reactor, real hydrocarbon batches, and methane sulfonic acid as the main catalytic medium at optimized conditions of pressure, temperature, and time.
The application of petroleum refining operations for the production of high-octane gasoline free of sulfur, olefins, and aromatics will continue to be in high demand for at least the next 30 years, where international policies on greenhouse gas mitigation will allow for the advent of new technologies for vehicle electrification.1 In the meantime, it is a high priority to ensure the production of high-quality fuels by, for example, improving existing processes, such as the isobutane/butene alkylation process, which has been present in many refineries worldwide since the 1930s.1,2 The isobutane/butene alkylation process was established as an auxiliary process for the production of aviation fuels, where sulfuric acid (H2SO4) and hydrofluoric acid (HF) were used as the catalysts par excellence.3 Today, such acid catalysts are still used in almost all alkylation plants worldwide, except in recent developments such as alkyclean (ABB Lummus), Lurgi Eurofuel, or Alkylene (UOP) or FBA (Haldor-Topsoe).2,3 It is in the latter development where an organic acid, trifluoromethanesulfonic acid (TFA), supported on silica, is used. Methanesulfonic acid (MSA), although a much less strong acid than TFA, is catalytically active in many organic transformations such as acylation, esterification, condensation, as well as alkylation of aromatic compounds, in cyclization and isomerization reactions.4,5 Moreover, MSA is considered a green catalyst due to its biodegradable nature, producing CO2 and sulfates as decomposition products.6-11 Similarly, AMS is much less corrosive and toxic in nature than many organic acids (LD50 in rats 650 mg/kg). Compared to TFA, MSA is very easy to handle and to separate in liquid form. In the present disclosure the use of methanesulfonic acid as a catalyst in isobutane/butene alkylation reactions is reported.
Ionic liquids (ILs) have already been tested on multiple occasions as alkylation catalysts. Most ILs are salts with a halometalate base anion as a Lewis acid source.4,12-15 Such halometalates, mostly aluminum (haloaluminates), have shown interesting catalytic activity and selectivity towards C8s in isobutane/butene alkylation reactions. However, they suffer from poor chemical stability due to anion hydrolysis reactions. This is why the chemical industry is searching for more stable catalysts that do not contain aluminum salts.
Provided below are references of documents of the state of the art related to the use of MSA as a catalyst in alkylation reactions.
U.S. Pat. No. 5,284,993 by Alan D., Eastman with publication date Feb. 8, 1994, describes a process for removing acid soluble oils, produced as an undesirable byproduct of an acid-catalyzed alkylation reaction, from a mixture containing a strong acid and methanesulfonic acid. The process includes using water to induce the formation of the two immiscible liquid phases of acid soluble oil (ASO) and MSA with water. The two immiscible phases can subsequently be separated from each other.16 It should be noted that the use of MSA as the sole catalyst in the Isoparaffin/Olefin alkylation process is not mentioned.
U.S. Pat. No. 5,292,986 by Ronald G. Abbott with publication date Mar. 8, 1994, relates to an alkylation catalyst used in processes for alkylating olefin hydrocarbons with isoparaffin hydrocarbons to produce high octane alkylate products suitable for use as a gasoline engine fuel blending component. The new catalyst comprises a mixture of a Lewis acid, a strong Bronsted acid and a predominant amount of a weaker acid. The new alkylation catalyst is used in a new process for alkylating olefinic hydrocarbons with isoparaffinic hydrocarbons. Specifically, the new catalyst comprises antimony pentafluoride, TMA and a predominant amount of MSA.17 This paper also does not suggest using AMS as the sole catalyst in the Isoparaffin/Olefin Alkylation process.
Similarly, identified below are technical papers in which the central theme only concerns the removal of olefins in aromatics via alkylation employing AMS as a catalyst: 1) “Gasoline Desulfurization by Catalytic Alkylation over Methanesulfonic Acid”, Xiaolin Wu; Yunpeng Bai; Ying Tian; Xuan Meng; Li Shi (2013);18 2) “A Novel Application of Methanesulfonic Acid as Catalyst for the Alkylation of Olefins with Aromatics”, Ying Tian; Xuan Meng; Ji-yun Duan; Li Shi (2012);19 3) “An efficient method for the alkylation of α-methylnaphthalene with various alkylating agents using methanesulfonic acid as novel catalyst and sovlents”, Zhongkui Zhao; Zongshi Li; Weihong Qiao; Guiru Wang; Lubo Cheng (2005);20 and, 4) “Use of methanesulfonic acid as a catalyst for the production of linear alkylbenzenes”, B. X Luong, A. L Petre, W. F Hoelderich, A Commarieu, J.-A Laffitte, M Espeillac, J.-C Souchet (2004), 18-21.21
The present disclosure is directed to overcoming these and other deficiencies in the art.
The present disclosure describes a new process of production of high-octane gasoline by mixing hydrocarbons coming from a refining plant containing olefins and isoparaffins with an organic acid (AMS), under variable conditions of pressure between 2 and 6 MPa, temperature, between 0 and 140° C., and time, from 5 to 30 min and the fixed conditions of minimum catalyst/hydrocarbon ratio of 50 wt % at 1500 rpm minimum of propellant agitation.
Therefore, one of the objects of the present disclosure is to provide a new process for the production of high-octane gasoline by blending hydrocarbons coming from a refining plant, which contains a mixture of olefins and kerosenes, among which are the precursor molecules of alkylation gasoline.
A further object of the present disclosure is to provide the use of MSA as a single catalyst in an alkylation process with high yields, which are comparable to those obtained by sulfuric acid, applied under its own reaction conditions.
With the aim clarify the description of the process for the production of alkylate gasoline, through the use of refinery mixtures and organic acids, subject of this disclosure, reference to the drawing will be made, with no limitation of the scope of the present disclosure:
The present disclosure describes a new process to produce alkylation gasoline by using a batch reactor in which a hydrocarbon load from an alkylation plant composed of olefins and iso-paraffins, and methanesulfonic acid used as catalyst. Hydrocarbons and catalyst are mixed under certain conditions of pressure, time, and temperature, at a weight ratio equal to or less than 50% catalyst to hydrocarbons, and with a stirring of not less than 1500 rpm. The alkylated product maintains the quality to that obtained with commercial catalysts such as sulfuric acid. The new catalyst can be reused without any pretreatment for up to 4 reaction cycles without showing a significant decrease in its catalytic activity.
With the use of hydrocarbon mixtures from a refinery, it is possible to convert iso-paraffins and alkenes into alkylation gasoline (alkylated product), using batch reactors and organic catalysts, such as methanesulfonic acid. The components of the reaction mixture to be transformed are listed in Table 1. This mixture corresponds to the typical feed composition of a hydrofluoric acid-based alkylation plant working in a local refinery in the central region of Mexico, under the operating standards of the state oil company (PEMEX).
The tests are carried out in a reaction apparatus as shown in
Before the hydrocarbon mixture is loaded into the reactor, the catalyst, which consists only of reagent grade methanesulphonic acid (99% purity), and without prior purification treatment, is added into a Teflon-lined reactor (a mass equivalent to 50% by weight of the hydrocarbon mixture), closing the reactor, and then vacuum is applied to the reactor using a vacuum pump.
After loading the catalyst, the reactor is pre-weighed and the weight is tared on a balance, after which the hydrocarbon mixture (50 weight % of the catalyst) is loaded at −5° C., using micrometric valves to control the flow. Once the reactor is loaded, it is connected to the heating grid, at a rate of 5° C./min until the desired temperature is reached. Once the working temperature (20 to 140° C.) is reached, nitrogen is injected into the reactor to achieve the working pressure. The system pressure (2 to 6 MPa) will tend to vary as the gasoline is formed.
After the reaction time has elapsed, the reactor is cooled down to room temperature to collect gas samples and then, to −5° C., the reactor is completely discharged and collected the liquid product, which is separated by decanting and neutralized with a saturated sodium bicarbonate solution. Both gaseous and liquid samples are taken for gas chromatographic analysis.
Experimental results. Preliminary experiments were carried out to determine the optimal conditions that allow to obtain high olefin conversions, with high C8 content, specially to trimethyl-pentanes (TMPs), which is demonstrated with the values of trimethylpentanes/dimethyl hexanes ratio (TMP/DMH) and the alkylate obtained alkylate volume. Therefore, 3 variables were chosen as the reaction's critical conditions to study, to name: pressure, temperature and reaction time. The interpretation of the results is described as follows:
Effect of the reaction temperature:
Effect of the reaction time. The reaction time exerts a significant effect on the gasoline quality that is obtained using the proposed process, this is due to the velocity at which the secondary reactions take place, producing undesired products. These tests were carried out under the following conditions: temperature 80° C., pressure 2 MPa, HC/MSA ratio 50 weight %, agitation: 1500 rpm at 4 different times (5, 10, 15 and 30 min). The results are shown in
Effect of the reaction pressure.
Effect of the catalyst/hydrocarbon (cat/HC) weight ratio.
Catalyst reuse. The gasoline production process here described can be boosted by the reuse of the single catalyst, namely, methanesulfonic acid. The reuse process can be described as follows:
Once the reaction time is accomplished, the reactor is vented, at −5° C. by using the scape valves. Later on, the reactor is opened, and the liquid content is decanted to a beaker at 0° C., where the volatiles are allowed to evaporate. Part of the catalyst remaining in the reactor is at the solid phase, which allows to be easily separated from the reaction products by decantation, so it can be used in a subsequent reaction cycle without any previous treatment. It is expected that a fraction of the catalyst is lost during the handling of the reactor, but also it can be lost due to its mixing with the alkylate product. In this case, the amounts of reactants are adjusted to the amount obtained of used catalyst.
The results up to this point shown demonstrate the capacity of MSA to catalyze the alkylation reaction of olefins and iso-paraffins, and its capacity to be recycled in subsequent reaction cycles. The regeneration process shown here is not limited to Batch experiments, but it can be replicated at continuous regime processes, provided that the technical modifications are done.
General considerations of the gasoline production process of this disclosure: Through this gasoline production process, methanesulfonic acid (MSA) is used as the single catalyst for the reaction; this catalyst allows a proper separation from the reaction products, leading to a facile reutilization of the catalyst, which, in other processes such as that catalyzed by sulfuric acid, is more complicated, having to regenerate it with fresh acid to keep a minimum acidity of 90%.
This process describes the production of alkylate gasoline through a batch reaction, where, in the following order, are mixed: methanesulfonic acid, hydrocarbon mixtures coming from an alkylation plant, and nitrogen. These are heated to a certain temperature and stirred for a certain amount of time. Once the reaction time has been accomplished, the mixture is cooled to 5° C. and the alkylation product separated from the catalyst by simple decantation. The catalyst can be regenerated by separating form the reaction effluent (decantation) and re-introduction into the reactor without further pre-treatment.
The following example is presented to illustrate the process of production of alkylate gasoline with refinery mixtures and organic acids and should not be considered as a limitation of the technical scope of the present disclosure, but they tend to be informative about the best way to employ methanesulfonic acid as single catalyst and its evaluation in a proper way.
In a batch reactor, provided with an internal Teflon lining, methanesulfonic acid is added in amounts within the range of 10-50 weight % of that of the gas mixture. One the reactor is charged; it is sealed and cooler to −5° C. Then, at this temperature, the gas mixture from refinery is injected by using the micrometric valves; such mixture contains olefins and iso-paraffins. Once the mixture is charged, the reactor is taken to a heating place and heating is started at about 5° C./min heating rate, up to the temperatures oscillating between 0 and 140° C. Once the reaction temperature is reached, nitrogen is injected until the working pressure is reached, which is between 2 and 6 MPa. The stirring is started at 1500 rpm through the reactors propel. The working pressure will slightly change due to the formation of the alkylate gasoline. Once the reaction time has been accomplished (which can go from 5 to 30 min) the stirring is switched off, the temperature is stabilized to the ambient one, and then a gas sample is taken by a valve and collected in a plastic bag. The reactor is then cooled to −5° C. and, at that temperature, it is open to extract the liquid product (gasoline), which is kept at the same temperature in a cool bath, and then allowed to reach ambient temperature. Finally, the alkylate is neutralized with a saturated solution of sodic bicarbonate. One neutral, the produced alkylate is taken to a gas chromatograph to determine the content of TMPs and C8s.
Citation of a reference herein shall not be construed as an admission that such reference is prior art to the present invention. All references cited herein are hereby incorporated by reference in their entirety. Below is a listing of various references cited with respect to this example:
| Number | Date | Country | Kind |
|---|---|---|---|
| MX/A/2023/009023 | Jul 2023 | MX | national |
