Heavy vacuum gas oil is converted into lighter products using a continuous stirred tank reactor

Abstract

Heavy vacuum gas oil is converted into lighter products using a continuous stirred tank reactor. The invention relates to a continuous stirred tank reactor that enables the conversion of heavy vacuum gas oil (HVGO), obtained from the vacuum distillation unit in petroleum refineries, into lighter products suitable for use as fuel through catalytic cracking under inert conditions.

Description

[0001] DESCRIPTION

[0002] Heavy vacuum gas oil is converted into lighter products using a continuous stirred tank reactor

[0003] Field of the Invention

[0004] The invention generally relates to obtaining light products and valuable basic chemical raw materials from petroleum refinery waste. Specifically, the invention pertains to a continuous stirred tank reactor that enables the conversion of heavy vacuum gas oil (HVGO), obtained from the vacuum distillation unit in petroleum refineries, into lighter products suitable for use as fuel through catalytic cracking under inert conditions.

[0005] State of the Art

[0006] Nowadays, hydrocracking and fluid catalytic cracking (FCC) processes are used to convert heavy vacuum gas oil (HVGO), obtained from the vacuum distillation unit of petroleum refineries, into lighter products suitable for use as fuel. Both hydrocracking and fluid catalytic cracking processes are carried out using catalysts, and generally, the same or similar catalysts are used in both processes. However, unlike the FCC process, the hydrocracking process takes place in a hydrogen gas environment. In the hydrocracking process, various types of reactors such as fixed-bed reactors, fluidized-bed reactors, and continuous stirred tank reactors are used, and the most suitable reactor type is selected depending on the properties of the petroleum residue and the number of carbon atoms in its structure. In the FCC process, fixed-bed reactors, moving-bed reactors, and fluidized-bed reactors are used.

[0007] In the reactors used in FCC and hydrocracking processes, a high volume fraction of catalysts is utilized. Over time, the pores on the surface of these catalysts partially or completely become blocked, leading to a significant loss of activity. Therefore, fresh catalyst feeding into the process is necessary. However, in the case of frequently used fixed-bed reactors, catalyst replacement requires prolonged shutdowns, resulting in substantial financial losses. In a hydrocracking process operating at 40,000 barrels per day, the cost per barrel ranges from $15 to $20, while the daily reactor shutdown cost can reach $600,000 to $800,000. Over a four-week catalyst replacement period, the total expenditure may rise to $18 to $24 million. In an FCC unit processing 60,000 barrels of vacuum gas oil per day, approximately 400-500 tons of catalyst are used. Additionally, due to the heavy residues of the processed petroleum in these reactors, blockages may occur, leading to high costs for reactor repair and maintenance. Since hydrocracking reactors operate under high temperatures and pressures, periodic maintenance and inspections must be carried out without interruption to prevent potential accidents and ensure occupational safety.

[0008] In the state of the art research conducted, certain documents have been identified. The document numbered WO2014158527A1 relates to a process for producing distillate fuel and anode-grade coke from vacuum residues. This document discusses the upgrading of waste hydrocarbon materials. The system described in this process mentions the use of a reactor, the addition of a catalyst, and the presence of a mixer.

[0009] The document numbered CN110387260A relates to the hydrogenation thermal cracking method of a hydrocarbon material derived from modified high-aromatic hydrocarbon wax oil. The described method explains the hydrogenation thermal cracking process of a hydrocarbon material consisting of a modified oil of high- aromatic hydrocarbon wax. This method mentions the use of a reactor, the addition of a catalyst, and the presence of a mixer.

[0010] In conclusion, improvements are being made to the reactors used for the conversion of heavy vacuum gas oil. Therefore, there is a need for new configurations that will eliminate the aforementioned disadvantages and provide solutions to existing systems. Aim of the Invention

[0011] The present invention relates to a continuous stirred tank reactor that meets the aforementioned requirements, eliminates all disadvantages, and provides additional advantages.

[0012] The primary objective of the invention is to enable the conversion of heavy vacuum gas oil (HVGO) into lighter products suitable for use as fuel through catalytic cracking under inert conditions. For this purpose, a continuous stirred tank reactor is utilized.

[0013] One objective of the invention is to prevent blockages in the reactor system caused by heavy petroleum residues during the catalytic cracking process of heavy vacuum gas oil. Simultaneously, it aims to establish a structure that reduces periodic maintenance costs and, overall, results in lower cost losses. Furthermore, in the continuous stirred tank reactor used during the conversion process of heavy vacuum gas oil, effective mixing reduces mass and thermal resistances, achieving better homogenization. This enables higher conversions and efficiency at lower temperatures, pressures, and catalyst concentrations.

[0014] Another objective of the invention is to prevent reactor shutdowns caused by catalyst replacement during the conversion process of heavy vacuum gas oil. This ensures the avoidance of significant cost losses associated with reactor shutdowns.

[0015] To achieve all the advantages mentioned above and detailed in the following description, the present invention is a continuous stirred reactor system that enables the conversion of heavy vacuum gas oil (HVGO), obtained from the vacuum distillation unit in petroleum refineries, into lighter products suitable for use as fuel through catalytic cracking under inert conditions.

[0016] The invention comprises the following components to achieve the described process: • A tank reactor where the heavy vacuum gas oil is fed and the reaction takes place,

[0017] • A catalyst feed system that supplies the catalysts used in the catalytic cracking reaction of the heavy vacuum gas oil into the tank reactor,

[0018] • A nitrogen gas feed system that removes air from the tank reactor and adjusts the reactor pressure,

[0019] • A mechanical mixer that ensures homogeneous mixing of the contents inside the tank reactor.

[0020] This configuration has been developed to achieve the intended objectives.

[0021] The structural and characteristic features of the invention, along with all its advantages, will be more clearly understood through the detailed description provided below, which references the accompanying figures. Therefore, the evaluation should be made by taking these figures and the detailed explanation into account.

[0022] Figures Clarifying the Invention

[0023] To best understand the configuration of the present invention and its advantages, along with additional components, it should be evaluated in conjunction with the figures described below.

[0024] Figure 1 provides a general view of the continuous stirred reactor system, which is the subject of the invention.

[0025] Elements Helping to Understand Figures

[0026] 1. Tank reactor

[0027] 2. Heavy vacuum gas oil feed

[0028] 3. Catalyst feed

[0029] 4. Nitrogen gas feed

[0030] 5. Pressure gauge

[0031] 6. Mechanical mixer

[0032] 7. Gas outlet valve 8. Liquid outlet valve

[0033] 9. Control unit

[0034] 10. Condenser

[0035] Detailed Description of the Invention

[0036] In this detailed description, the preferred configurations of the continuous stirred tank reactor, which is the subject of the invention, are explained solely for the purpose of better understanding the subject and without creating any limiting effect.

[0037] The invention is a continuous stirred reactor system that enables the conversion of heavy vacuum gas oil (HVGO), obtained from the vacuum distillation unit in petroleum refineries, into lighter products suitable for use as fuel through catalytic cracking under inert conditions. The system comprises:

[0038] • A tank reactor (1 ) where the heavy vacuum gas oil is fed and the reaction takes place,

[0039] • A catalyst feed (3) that supplies the catalysts used in the catalytic cracking reaction of the heavy vacuum gas oil into the tank reactor (1 ),

[0040] • A nitrogen gas feed (4) that removes air from the tank reactor (1 ) and adjusts the reactor pressure,

[0041] • A mechanical mixer (6) that ensures homogeneous mixing of the contents inside the tank reactor (1 ).

[0042] Figure 1 provides a general view of the continuous stirred tank reactor system, which is the subject of the invention. The catalytic cracking reaction of heavy vacuum gas oil under inert conditions takes place in a continuous stirred tank reactor (1 ). The tank reactor (1 ) is fed with raw heavy vacuum gas oil and catalyst without any priority order. The heavy vacuum gas oil is supplied through the heavy vacuum gas oil feed (2). Since heavy vacuum gas oil is in solid phase at room temperature, it is heated until it liquefies and then fed into the tank reactor (1 ). The catalyst is fed into the tank reactor (1 ) through the catalyst feed (3). In order to remove the air inside the tank reactor (1 ), nitrogen gas is fed into the tank reactor (1 ) via the nitrogen gas feed (4). By opening the gas outlet valve (7) connected to the tank reactor (1 ), the nitrogen gas, along with the air, is expelled from the tank reactor (1 ). This process can be repeated multiple times to ensure complete removal of air from the tank reactor (1 ). The catalytic cracking reaction of heavy vacuum gas oil can occur under both pressurized and non-pressurized conditions. In cases where the catalytic cracking reaction is to take place under pressure, nitrogen gas is used to maintain a pressure of 0-30 bar inside the tank reactor (1 ). The pressure in the tank reactor (1 ) is monitored using the pressure gauge (5) connected to the tank reactor (1 ). After the desired pressure is achieved in the tank reactor (1 ), the temperature value at which the catalytic cracking reaction will take place is adjusted by the control unit (9) and the tank reactor (1 ) temperature is brought to the desired level. After the heavy vacuum gas oil is heated and transitions to the liquid phase, the mechanical mixer (6) located inside the tank reactor (1 ) is activated. The catalytic cracking reaction time of the heavy vacuum gas oil starts from the moment the tank reactor (1 ) temperature reaches the set catalytic cracking reaction temperature. After the end of the reaction period and the cooling of the tank reactor (1 ), the gases in the tank reactor (1 ) are first removed. However, before the gases coming out of the tank reactor (1 ) are released to the outside, they are passed through the condenser (10) and after gaining the condensed liquid products, the liquid products in the tank reactor (1 ) are taken from the liquid outlet valve (8).

[0043] In a preferred configuration of the invention, the conversion of heavy vacuum gas oil into lighter products through catalytic cracking under inert conditions in a continuous stirred reactor system is carried out under the following process conditions:

[0044] - Reaction temperature: 375-460 °C

[0045] - Reaction pressure: 80-140 bar (Initial nitrogen gauge pressure: 10-30 bar)

[0046] ~0 bar (Initial nitrogen gauge pressure: 0 bar)

[0047] - Reaction time: 10-180 minutes

[0048] - Catalyst concentration: 0.01 -5% by weight

[0049] - Stirring speed: 100-1200 rpm In the mentioned process, as catalyst various metals or metal oxide impregnated on natural and synthetic zeolites, alumina, and silica can be used as catalysts. The continuous stirred tank reactor system, which is the subject of the invention, offers advantages in terms of maintenance costs and, thanks to its mixing capability, can operate with catalyst concentrations ranging from 0.01 % to 5% by weight. Additionally, deactivated catalysts can be removed from the reactor along with the cracking products. Due to the reactor geometry and mixing feature, blockages do not occur in the continuous stirred tank reactor. Additionally, the catalytic cracking reaction can be carried out under both pressurized conditions (using inert nitrogen gas) and non-pressurized conditions, enabling the conversion of heavy vacuum gas oil into lighter products suitable for use as fuel under safer conditions.

Claims

CLAIMS1. A continuous stirred reactor system that enables the conversion of heavy vacuum gas oil (HVGO), obtained from the vacuum distillation unit in petroleum refineries, into lighter products suitable for use as fuel through catalytic cracking under inert conditions, characterized by:• A tank reactor (1) where the heavy vacuum gas oil is fed and the reaction takes place,• A catalyst feed (3) that supplies the catalysts used in the catalytic cracking reaction of the heavy vacuum gas oil into the tank reactor (1 ), • A nitrogen gas feed (4) that removes air from the tank reactor (1 ) and adjusts the reactor pressure,• A mechanical mixer (6) that ensures homogeneous mixing of the contents inside the tank reactor (1).

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