A method for desulfurization of high-sulfur inferior heavy oil

Abstract

This invention discloses a desulfurization method for high-sulfur, low-quality heavy oil, comprising: (1) the low-quality heavy oil in the raw material tank is pumped to the packed reactor by the raw material pump, and under certain temperature, pressure and space velocity, the sulfur-containing compounds in the low-quality heavy oil react with the iron packing; (2) the reaction products enter the gas-liquid separator for gas-liquid separation, the gas phase product is sent to the boiler as fuel, and the liquid phase product is divided into two paths, one path is pumped to the product tank by the product pump, and the other path is circulated to the raw material pump inlet by the product pump to mix with fresh raw materials. This invention specifically reacts the sulfur-containing compounds in the low-quality heavy oil with the iron packing. The inactive sulfides decompose into active sulfides at high temperature. The thiols in the active sulfides react with iron to generate ferrous sulfide and corresponding hydrocarbons. Hydrogen sulfide reacts with iron to generate ferrous sulfide and hydrogen. Elemental sulfur reacts with iron to generate ferrous sulfide. This invention does not consume hydrogen, does not use a catalyst, has mild reaction conditions, simple process, and low cost.

Description

Technical Field

[0001] This invention relates to a method for desulfurizing oil products, and more particularly to a method for desulfurizing high-sulfur, low-quality heavy oil. Background Technology

[0002] Currently, the properties of global crude oil are trending towards heavier and lower quality, and the reserves of heavy and lower quality crude oil are enormous, representing important resources for future processing and utilization. Besides heavy and lower quality crude oil, atmospheric residue and vacuum residue obtained from crude oil distillation, slurry oil from catalytic cracking units, and heavy ethylene tar from ethylene cracking units are also important low-quality heavy oil resources with large production volumes. Low-quality heavy oil has an extremely complex composition, high density, viscosity, and carbon residue, and contains large amounts of non-hydrocarbon low-quality components such as gums and asphaltenes, as well as high levels of heteroatoms such as sulfur, nitrogen, and metals. Its storage, transportation, and processing have become major challenges facing the refining industry today. The high sulfur content of low-quality residue oil can easily cause catalyst poisoning during processing and seriously affect product quality, posing numerous technical challenges to the lightening and cleaner production of heavy oil. Furthermore, when low-quality heavy oil is used as marine fuel oil, its sulfur content is subject to strict limits to prevent pollution from ship emissions. Therefore, the sulfur content of low-quality heavy oil must be reduced to an acceptable range before comprehensive utilization.

[0003] Traditional desulfurization methods for low-quality heavy oil mainly include hydrodesulfurization, oxidative desulfurization, adsorption desulfurization, and biological desulfurization. Currently, hydrodesulfurization remains the mainstream technology, converting sulfur-containing compounds in low-quality heavy oil into more easily removed substances such as hydrogen sulfide. It boasts high desulfurization efficiency but requires hydrogen, relies on catalysts, and operates under relatively harsh pressure conditions. Oxidative desulfurization is a desulfurization technology that has gradually developed in recent years. Compared to hydrodesulfurization, it does not require hydrogen and operates under milder reaction conditions. However, oxidative desulfurization is currently in the basic research stage, and many issues need to be resolved before industrialization. Adsorption desulfurization selectively adsorbs sulfur-containing compounds using adsorbents. It features simple operation, high desulfurization efficiency, and strong adsorbent regeneration performance. However, adsorbents are unstable at high temperatures, and the adsorbed substances are mainly thiols and sulfides. Biological desulfurization utilizes microorganisms for desulfurization under ambient temperature and pressure without using complex and toxic chemicals. However, desulfurization is time-consuming, and microorganisms generally suffer from issues related to activity, selectivity, and lifespan.

[0004] Therefore, the above-mentioned desulfurization methods for inferior heavy oil all have various limitations, and hydrodesulfurization is the main method, so the available methods are very limited. There is a need for a new desulfurization method that is low in cost, low in energy consumption, and simple in process. Summary of the Invention

[0005] The purpose of this invention is to provide a desulfurization method for high-sulfur, low-quality heavy oil to solve the technical problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a desulfurization method for high-sulfur, low-quality heavy oil, comprising the following two steps:

[0007] (1) The inferior heavy oil in the raw material tank is pumped to the packed reactor by the raw material pump. Under certain reaction temperature, reaction pressure and mass hourly space velocity, the sulfur-containing compounds in the inferior heavy oil react with the iron packing to obtain reaction products.

[0008] (2) The reaction products enter the gas-liquid separator for gas-liquid separation. The gas phase products are sent to be used as boiler fuel, and the liquid phase products are divided into two paths. One path is sent to the product tank by the product pump, and the other path is sent to the raw material pump inlet by the product pump to be mixed with fresh raw materials.

[0009] Preferably, in step (1), the packing material used in the packed reactor is one of iron mesh, iron chain, iron sheet, and iron granules.

[0010] Preferably, in step (1), the reaction temperature is 200~400℃, the reaction pressure is 0.5~2MPa, and the mass hourly space velocity is 1~10h. -1 .

[0011] Preferably, in step (2), the cycle ratio of the cyclic operation is 0 to 5.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. This invention addresses the corrosion mechanism of high-sulfur, low-quality heavy oil on refinery equipment and pipelines. It specifically targets the reaction of sulfur-containing compounds in the low-quality heavy oil with iron filler. Inactive sulfides decompose into active sulfides at high temperatures. Thiols and other compounds in the active sulfides react with iron to form ferrous sulfide and corresponding hydrocarbons. Hydrogen sulfide reacts with iron to form ferrous sulfide and hydrogen gas. Elemental sulfur also reacts with iron to form ferrous sulfide. Compared to traditional hydrodesulfurization processes, the method described in this invention does not consume hydrogen gas, does not use a catalyst, has mild reaction conditions, is simple, and has low cost.

[0014] 2. The method of the present invention has a flexible cycle ratio setting, and can also be set without circulation, depending on the desulfurization rate or processing capacity requirements. Attached Figure Description

[0015] Figure 1 This is a flow chart of the desulfurization process for inferior heavy oil in this invention. Detailed Implementation

[0016] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto.

[0017] Example 1: Desulfurization method for atmospheric residue oil, as detailed below:

[0018] (1) The atmospheric residue oil (sulfur content of 3.3%) in the feed tank is pumped to the packed reactor (with iron chain as packing) by the feed pump. The reaction temperature is 350℃, the pressure is 1MPa, and the mass hourly space velocity is 3h. -1 This causes the sulfur-containing compounds in the atmospheric residue to react with the filler;

[0019] (2) The reaction products enter the gas-liquid separator for gas-liquid separation. The gas phase products are sent to be used as boiler fuel. The liquid phase products are divided into two paths. One path is sent to the product tank by the product pump, and the other path is sent to the raw material pump inlet by the product pump to be mixed with fresh raw materials. The circulation ratio is 2, and the desulfurization rate of the products reaches 86.3%.

[0020] Example 2: Desulfurization method for catalytic oil slurry, as detailed below:

[0021] (1) The catalytic oil slurry (sulfur content of 1.2%) in the feed tank is pumped to the packed reactor (with iron chain as packing) by the feed pump. The reaction temperature is 380℃, the pressure is 1MPa, and the mass hourly space velocity is 3h. -1 This causes the sulfur-containing compounds in the catalytic oil slurry to react with the filler;

[0022] (2) The reaction products enter the gas-liquid separator for gas-liquid separation. The gas phase products are sent to be used as boiler fuel. The liquid phase products are divided into two paths. One path is sent to the product tank by the product pump, and the other path is sent to the raw material pump inlet by the product pump to be mixed with fresh raw materials. The circulation ratio is 3, and the desulfurization rate of the products reaches 82.6%.

[0023] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A desulfurization method for high-sulfur, low-quality heavy oil, characterized in that, Includes the following steps: (1) The inferior heavy oil in the raw material tank is pumped to the packed reactor by the raw material pump. Under certain reaction temperature, reaction pressure and mass hourly space velocity, the sulfur-containing compounds in the inferior heavy oil react with the iron packing to obtain reaction products. (2) The reaction products enter the gas-liquid separator for gas-liquid separation. The gas phase products are sent to be used as boiler fuel, and the liquid phase products are divided into two paths. One path is sent to the product tank by the product pump, and the other path is sent to the raw material pump inlet by the product pump to be mixed with fresh raw materials. In step (1), the packing material used in the packed reactor is one of the following: iron mesh, iron chain, iron sheet, and iron granules; In step (1), the reaction temperature is 200~400℃, the reaction pressure is 0.5~2MPa, and the mass hourly space velocity is 1~10h. -1 ; In step (2), the cycle ratio of the loop is 0 to 5.

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