Catalytic reforming process

CCR feedstocks are generally naphtha obtained under atmospheric pressure through catalysis and diesel hydrogenation. The products mainly include clean, high-octane gasoline and liquefied gas, as well as raw materials for aromatic extraction units; the by-product is hydrogen. I think liquefied gas is also a by-product. Process characteristics: high temperature and low pressure

There’s also cracked straight-run naphtha! The pressure isn’t high! It’s okay!

Why is a dechlorination tank required in the reformation process? Which expert can explain this@!

Reply to 4# longlong1213827: There are two types of dechlorinating agents used in the reprocessing process. The first type is used in the pretreatment stage and is a high-temperature dechlorinating agent; its purpose is to remove chlorine and prevent the formation of ammonium salts that could clog the pipelines. The second type is used for dechlorinating hydrogen, with the aim of improving the purity of the hydrogen (which is needed in downstream processes such as diesel hydrogenation; here, part of the hydrogen is mixed with liquefied gas before being burned). I hope this helps you

How is chlorine generated during reformation? Does the catalyst need to be chlorinated?

The chlorine in the pre-hydrogenated material comes mainly from crude oil, whereas the chlorine in the hydrogen comes primarily from catalyst regeneration

Chlorine in the reforming reaction system comes mainly from two sources: 1 is introduced with the feedstock, and 2 is added to the system. Chlorine injection is necessary, as the catalyst must maintain a water-chlorine balance to perform at its best. The pre-hydrogenation unit is equipped with dechlorination tanks (one at high temperature and one at low temperature). The purpose is: 1) to reduce ammonium salt crystallization and prevent blockages in pipes and heat exchangers; 2) to minimize equipment corrosion in downstream hydrogen-using devices (such as hydrogenation units), as chloride ions cause severe corrosion of stainless steel, as well as damage to catalysts.

Thank you. Could you please explain in more detail? I work in hydrogen production facilities and am not familiar with reforming processes. We use hydrogen produced through reforming, and there are specifications regarding the chlorine content in that hydrogen! Because chloride ions have a significant impact on the equipment in hydrogenation units, they can easily cause chloride stress corrosion in austenitic stainless steel!

First, the feedstocks for catalytic reforming include straight-run heavy naphtha from atmospheric and vacuum distillation, hydrocracked naphtha, and extract oils. The boiling range of the feedstock depends on the type of production in the facility. The main purpose of catalytic reforming is to produce high-octane blended gasoline or aromatics; high-octane gasoline is produced at temperatures around 80–180°C, while aromatics are produced at temperatures around 60–165°C. At our integrated facility, the operating range is currently around 80–175°C. II. The refining-type aromatic production units mainly produce high-octane gasoline, liquefied gas, by-product hydrogen, benzene, toluene, mixed xylene (or m-p-xylene, o-xylene), heavy aromatics, and residue oil. III. High temperature and low pressure, high octane number, and high aromatic yield. IV. The chlorine during reformation originates from the \"water-chlorine balance\" of the catalyst; after catalyst regeneration, a chlorination-oxidation process takes place during which chlorine is added, with the aim of replenishing chlorine and dispersing the metal on the catalyst surface. Therefore, chlorine needs to be removed in the subsequent stages of the reforming reaction; hydrogen dechlorination tanks and reformate dechlorination tanks are installed to reduce the material requirements for downstream equipment and pipelines. Generally, a dechlorination tank is also installed after the pre-hydrogenation reactor for the same purpose: dechlorination in order to extend the lifespan of the downstream equipment and pipelines. Welcome to continue the discussion!

Catalytic reforming: The process of rearranging the molecular structures of hydrocarbon molecules in gasoline fractions into new molecular structures under the action of a catalyst is called catalytic reforming. One of the processes in petroleum refining, in which, under conditions of heating, hydrogen pressure, and the presence of a catalyst, the light gasoline fractions (or naphtha) obtained from crude oil distillation are converted into high-octane gasoline rich in aromatics (reformed gasoline), with liquefied petroleum gas and hydrogen being produced as by-products. Reformated gasoline can be used directly as a component in gasoline blending, or it can be used to produce benzene, toluene, and xylene through aromatic extraction. The by-produced hydrogen is an important source of hydrogen for the hydrogenation units in oil refineries (such as hydrorefining and hydrocracking). Main reaction types: Include the following four main reactions: ① Naphthenes dehydrogenation ； ②Alkane dehydrocyclization ； ③Isomerization ； ④Hydrocracking. Reactions ① and ② produce aromatics while generating hydrogen; the reactions are endothermic ； Reaction ③ rearranges the hydrocarbon molecule structure; it is an exothermic reaction (with a modest heat effect) ； Reaction ④ breaks down large molecular alkanes into lighter alkanes and low-molecular-weight gases, which reduces the yield of liquid products and consumes hydrogen; the reaction is exothermic. In addition to the reactions mentioned above, there are also reactions such as the saturation of olefins and coking. The extent to which these various reactions occur depends on the operating conditions, the properties of the raw materials, and the type of catalyst used. Process conditions: The raw material is naphtha or low-quality gasoline, which contains alkanes, cycloalkanes, and aromatics. Feedstocks with a high content of naphthenes are good feedstocks for reforming. When catalytic reforming is used to produce high-octane gasoline, the feedstock is a wide-range fraction with a boiling point range of generally 80–180℃ ； When used in the production of aromatics, the feed is a narrow fraction with a boiling point range of generally 60–165°C. Olefins, water, and impurities such as arsenic, lead, copper, sulfur, and nitrogen in the reforming feedstock can poison the catalyst and cause it to lose its activity; therefore, they need to be removed before entering the reforming reactor. The factors affecting this process include, in addition to the properties of the raw materials and the type of catalyst, temperature, pressure, space velocity, and the hydrogen-to-oil ratio. High temperature, low pressure, low space velocity, and a low hydrogen-to-oil ratio are favorable for the formation of aromatics, but these parameters need to be kept within certain ranges in order to suppress coking reactions. Furthermore, in order to achieve the best catalytic activity and catalyst selectivity, appropriate chlorides are sometimes added during operation to maintain a stable chlorine content in the catalyst. Process flow: It mainly includes two steps, raw material pretreatment and reforming; when the goal is to produce aromatics, it also involves aromatics extraction and distillation units. The pre-treated feedstock enters the reforming section, where it is mixed with recycled hydrogen and heated to 490–525°C before entering the reactor at a pressure of 1–2 MPa. The reactors are connected in series, 3 to 4 in number, with a heating furnace installed between them to compensate for the heat absorbed by the reaction. The material leaving the reactor enters a separator where the hydrogen-rich recycle gas is separated (with the excess being discharged); the resulting liquid has its light components removed in a stabilizer tower and is then used as reformate gasoline, which is a high-octane gasoline component (with an octane number of over 90 according to the research method), or it is sent to an aromatic extraction unit for the production of aromatics.