A Review of Modelling of the FCC Unit—Part II: The Regenerator

Heavy petroleum industries, including the Fluid Catalytic Cracking (FCC) unit, are among some of the biggest contributors to global greenhouse gas (GHG) emissions. The FCC unit’s regenerator is where these emissions originate mostly, meaning the operation of FCC regenerators has come under scrutiny in recent years due to the global mitigation efforts against climate change, affecting both current operations and the future of the FCC unit. As a result, it is more important than ever to develop models that are accurate and reliable at predicting emissions of various greenhouse gases to keep up with new reporting guidelines that will help optimise the unit for increased coke conversion and lower operating costs. Part 1 of this paper was dedicated to reviewing the riser section of the FCC unit. Part 2 reviews traditional modelling methodologies used in modelling and simulating the FCC regenerator. Hydrodynamics and kinetics of the regenerator are discussed in terms of experimental data and modelling. Modelling of constitutive parts that are important to the FCC unit, such as gas–solid cyclones and catalyst transport lines, are also considered. This review then identifies areas where the current generation of models of the regenerator can be improved for the future. Parts 1 and 2 are such that a comprehensive review of the literature on modelling the FCC unit is presented, showing the guidance and framework followed in building models for the unit.

A Review of Modelling of the FCC Unit. Part I: The Riser

Heavy petroleum industries, including the fluid catalytic cracking (FCC) unit, are useful for producing fuels but they are among some of the biggest contributors to global greenhouse gas (GHG) emissions. The recent global push for mitigation efforts against climate change has resulted in increased legislation that affects the operations and future of these industries. In terms of the FCC unit, on the riser side, more legislation is pushing towards them switching from petroleum-driven energy sources to more renewable sources such as solar and wind, which threatens the profitability of the unit. On the regenerator side, there is more legislation aimed at reducing emissions of GHGs from such units. As a result, it is more important than ever to develop models that are accurate and reliable, that will help optimise the unit for maximisation of profits under new regulations and changing trends, and that predict emissions of various GHGs to keep up with new reporting guidelines. This article, split over two parts, reviews traditional modelling methodologies used in modelling and simulation of the FCC unit. In Part I, hydrodynamics and kinetics of the riser are discussed in terms of experimental data and modelling approaches. A brief review of the FCC feed is undertaken in terms of characterisations and cracking reaction chemistry, and how these factors have affected modelling approaches. A brief overview of how vaporisation and catalyst deactivation are addressed in the FCC modelling literature is also undertaken. Modelling of constitutive parts that are important to the FCC riser unit such as gas-solid cyclones, disengaging and stripping vessels, is also considered. This review then identifies areas where current models for the riser can be improved for the future. In Part II, a similar review is presented for the FCC regenerator system.

Sustainable Remediation of Soils Contaminated with Petroleum Products

In nature, it acts, simultaneously or successively, synergistically or antagonistically, on small or larger spaces, for a long or very short time, numerous natural or artificial processes that pollute, leading to the alteration of the quality of the environment. The basic activity carried out within the oil scaffolding consists in the extraction of crude oil and gases from the deposits in their exploitation, their collection, separation of phases (crude oil, reservoir water, gas), crude oil treatment, storage and sending to users. Contamination of the field related to drilling-extraction wells with crude oil, heavy petroleum products, salt water, various chemicals, etc. has a random character, but with undesirable implications on soil, surface water and / or groundwater, depending on the nature of the pollutant, its quantity and area of spread Pollution sources in the oil industry, both systematic and accidental, have a greater or lesser spread, depending on the size of the field, the type and composition of the extracted fluids, the extraction technology used, the age of oil exploitation in the area, relief and hydrographic network. Having available the data provided by the pollution diagnosis, it is possible to assess the risk that the investigated pollution represents for the people on the site and for the natural environment. If it turns out that the risk is significant, then the decision is made to switch to depollution works. The choice of an appropriate depollution path is made on the basis of relevant technical and economic criteria, which is a feasibility study. The proposed depollution technology must be the most appropriate for the case at hand and, at the same time, be available on the technology market. The most important part of the paper is dedicated to presenting the results of an experimental study on the depollution of soils contaminated with liquid petroleum products by sparging technologies, in order to ensure a sustainable remedy. The results of the soil analysis used in the experimental determination are presented, as well as the physic - chemical characteristics of the main soil pollutants. In the experimental part, laboratory decontamination of systems consisting of polluted soils was performed at the laboratory level, using air as a depollution agent. The processing of the data obtained from the experimental determinations allowed obtaining qualitative and quantitative information related to the decontamination speed depending on the nature of the soil, the nature and concentration of the pollutant and the temperature of the decontamination air. Estimating the cost places this technology at a low level compared to thermal technologies and slightly higher than microbiological technologies.

Gel-permeation chromatography as a method for monitoring transformations of heavy petroleum fractions during secondary oil refining

A rapid and easy to use method for monitoring transformations of heavy oil fractions during secondary processes of oil refining is proposed. The method is based on the study of changes in the molecular weight characteristics by gel-permeation chromatography (GPC) using a refractometric detector. Optimal conditions for registration of the chromatograms (temperature, eluent consumption and its composition) were specified. Heptane, toluene, and toluene added with 1% and 5% of methanol were studied as eluents, the polarity indices being arranged in a series 0.2; 2.4; 2.43; 2.54. The effect of the nature of the solvent on the type of the product chromatogram is determined. It is shown that addition of a polar solvent to a nonpolar one increases the polarity index, reduces both the degree of association of petroleum molecules and adsorption on the gel. The most available toluene which meets the GPC requirements is chosen as an eluent. Addition of 1% CH3OH to the eluent promotes suppression of polyelectrolyte effects and adsorption. The revealed absence of the dependence of the retained volume and the type of chromatograms on the eluent flow rate and temperature indicates that separation is carried out under conditions of exclusion and completely obeys the theory of exclusive liquid chromatography. The transformation of raw materials during a technological process of oil production at the JSC «ANKhK» was studied using the GPC method under above-mentioned chromatographic conditions. We have studied vacuum distillate of the primary oil refining unit ELOU+AVT-6 (VD) and the product of hydrocracking of the vacuum distillate of the 123PM unit (HVD). It is shown that determination of the molecular weight characteristics provides an important information about the behavior of technological processes. The HVD meets the requirements for hydrocracking products. A decrease in the content of aromatic hydrocarbons in comparison with the raw feedstock is proved by the data of thin layer chromatography (TLC).