Fluid Catalytic Cracking Plant Research Articles

Polyethylene waste co-processing in fluid catalytic cracking plants

Plastics pollution is an overwhelming environmental problem that must be solved as soon as possible. Refining processes such as the Fluidized Catalytic Cracking (FCC) process with a global capacity of 14 million barrels per day, may help to solve it in the short term, as many scientists have already pointed out. Just by co-processing 5 wt % polyethylene waste in those units, 37 million tons per year of polyethylene could be eliminated from landfills and transformed into valuable fuels. However, refiners must be completely sure that processing polyethylene in their FCC plants will not cause any deleterious effects. That is the purpose of this paper.Low density polyethylene waste was transformed into valuable hydrocarbons by co-processing in proportions of 5 and 10 wt % with heavy gasoil in an FCC pilot plant which operates as industrial FCC plants do. Polyethylene was completely converted mainly into naphtha and liquified petroleum gas; at 510 °C polyethylene was converted into naphtha (46 %), LPG (20 %), light cyclic oil (9 %), heavy cyclic oil (15 %), coke (6 %) and dry gas (4 %); at 530 °C, the order and proportions changed significantly, naphtha (43 %), LPG (35 %), heavy cyclic oil (0 %), light cyclic oil (2 %), coke (8 %) and dry gas (12 %); LPG olefinicity and naphtha research octane number increased slightly. No catalyst circulation problems nor clogging or plugging were observed. However, at the highest experimental reaction temperature (530 °C), dry gas yield increased to more than 4 wt %, this could be a problem for most of industrial plants since it may overload the wet gas compressor.

Effect of spent fluid catalytic cracking (FCC) catalyst on syngas production from pyrolysis and CO2-assisted gasification of waste tires

With growing demands for improved energy recovery from waste tires, incorporating waste catalysts from different sectors can provide synergistic solution. This paper investigates the effect of using spent fluid catalytic cracking (FCC) catalyst on evolutionary behavior and yield of syngas (CO, H2, and light hydrocarbons), and char and energy yields during pyrolysis and CO2-assisted gasification of waste tires at 900 °C in a fixed-bed semi-batch reactor. The effect of catalyst position (in-situ and quasi-in-situ catalytic modes) and temperature was also examined during catalytic CO2-assited gasification for energy and chemicals production. The results reveal that the presence of spent FCC catalyst resulted in higher syngas and energy yields. The CO2-assisted gasification provided CO-rich syngas with higher yields than pyrolysis. The quasi-in-situ gasification provided increased syngas and energy yields by 24% and 23% respectively, as compared to in-situ catalytic gasification, which revealed that quasi-in-situ catalytic gasification to be more efficient and effective for increased syngas yields. Increasing temperature to 950 °C increased the yields syngas and energy owing to improved reforming and cracking reactions. This viability of utilizing spent FCC catalyst offers improved waste management economics for FCC plants while simultaneously improving the energy recovery from waste tires.

Wood Derived Fast Pyrolysis Bio-liquids as Co-feed in a Fluid Catalytic Cracking Pilot Plant: Effect of Hydrotreatment on Process Performance and Gasoline Quality.

Co-feeding biogenic feeds in fluid catalytic cracking (FCC) units benefits from exploiting existing refinery assets to produce biogenic fuels. It is the most cost-effective way to comply with step-by-step increasing the target of renewable energy in road and rail transport of the European Union. Fast pyrolysis bio-liquids derived from wood offer a unique opportunity to reach those targets without having to address the typical food vs fuel debate. In the present work bio-liquids derived from pinewood in different stages of treatment were tested for their processability in a pilot scale fluid catalytic cracking plant at 550 °C. Specific focus is on the quality of the derived gasoline fractions. All samples were co-fed with vacuum gas oil, a typical FCC feed. Relevant parameters to qualify the produced gasoline as blending component were analyzed. As main results, none of the parameters examined significantly affect the quality of the—now partially biogenic—gasolines, demonstrating the potentiality of the co-FCC process as a possible near future pathway to ensure high biofuel contents in commercially available fuels.

Online Tuning Diagnosis of Proportional Integral Derivative Controller based on IEC 61499 Function Blocks

Controller performance is a crucial aspect of industrial processes; hence, it is critical to maintaining optimal controller performance conditions. Bad controller performance can be caused by poor proportional integral derivative (PID) controller tuning those results in aggressive and sluggish controllers’ behavior. Correct diagnosis of poor controller tuning becomes vital so that it can adequately handle the controller. This study designs several function blocks for online diagnosis of poor PID controller tuning based on the IEC 61499 standard. The design of the function blocks began with design the method used for diagnosing a poor controller tuning. The procedure was based on autocorrelation function (ACF), comparison of signal to noise ratio (SNR) estimation, and idle index. The function blocks were validated with first order plus delay time (FOPDT) processes, which had aggressive, sluggish, or well-tuned behavior. The function blocks were implemented on a Fluid Catalytic Cracking (FCC) plant and industrial data with various process faults to evaluate its capability to diagnose a poor controller tuning. The developed function block can precisely analyze a poor controller tuning on FCC plant and 8 of 10 industrial data. It showed that the function blocks could diagnose a poor controller tuning correctly if the oscillation were regular.

Various Ways for Increasing Production of Middle Distillate

Currently, refiners are experiencing a big challenge due to the slow economic growth, over diesel production and decreased demand of it. Refineries are searching for technologies that could reduce diesel output, particularly the inferior light cycle oil (LCO) fraction. Here in, this article mainly we will describes the industrialized technologies for LCO processing such as LCO upgrading, LCO blending into available plants such as fluid catalytic cracking (FCC), and hydro-refining/treating unit, LCO moderate hydrocracking, and LCO to some aromatic rich stream and also with gasoline with the integration of selective hydro-refining and resulting optimized FCC unit. It is analyzed that the LCO moderate hydrocracking can provide more gasoline at the expense of high H2 consumption, while LCO to aromatics and gasoline (LTAG) technology needs more steps for clean fuel production and retrofitting of FCC plant. Based on the analyses of current technologies, it is suggested that implementation of such technologies should consider the configuration of refineries, as well as the benefit of end users.

Optimal retrofit of heat exchanger networks: A stepwise approach

This paper introduces a new stepwise approach for the optimal retrofit of heat exchanger networks. At each iteration, the proposed method involves superstructures which embed retrofit alternatives as well as numerical optimization to minimize the project’s total annualized cost. In order to reduce calculation times, new algorithms are proposed to thin out superstructures. These are based on thermodynamic criteria, namely on the concept of heat path, and on new graph theoretical results. To carry out the numerical optimization tasks, novel mixed integer nonlinear models are developed. These models support any combination of constant, polynomial and (continuous) piecewise linear enthalpy functions of temperature. Numerical examples are presented for the retrofit of the preheat train of an atmospheric crude unit and for the retrofit of a fluid catalytic cracking plant. The new method is shown to reduce calculation times and total annualized costs reported in the literature.

Economic Model Predictive Control of an Industrial Fluid Catalytic Cracker

Fluid catalytic cracking (FCC) is an important refinery process by which heavy hydrocarbons are cracked to form lighter valuable products over catalyst particles. FCC plants consist of the riser (reactor), the regenerator, and the fractionator that separates the riser effluent into the useful end products. In FCC plants the product specifications and feedstocks change due to varying economic and market conditions. In addition, FCC plants operate with large throughputs and a small improvement realized by optimization and control yields significant economic return. In previous work, we developed a nonlinear dynamic model and validated it with industrial data. In this study, our focus involves the development and application of a real-time optimization framework. We propose a hierarchical structure which includes a two-layer implementation of economic model predictive control (EMPC). EMPC provides the optimal riser and the regenerator temperature reference trajectories which are determined from a dynamic optimization problem maximizing the plant profit. A regulatory model predictive controller (RMPC) manipulates the catalyst circulation rate and the air flow rate to track the reference trajectories provided by EMPC. We consider changes in product prices and the feed content, both of which necessitate online optimization. Dynamic simulations show that the proposed hierarchical control structure achieves optimal tracking of plant profit during transitions between different operating regimes thanks to the combined efforts of EMPC and RMPC.

Retrofit design of heat exchanger network of a fluid catalytic cracking plant and control based on MPC

Nowadays, the optimal control of a heat-integrated plant becomes one of the most important research areas in the chemical industry. The heat transfer between the process and recycle flows may generate instability. Accordingly, the advanced control techniques have the challenging task of assuring the safety of the process operation and providing tight control for the heat integrated plants. Investigation of an entire fluid catalytic cracking (FCC) plant taking into account its complex dynamic behaviour for heat integration design and operation has not been studied yet. The reactor–regenerator, the fractionation column and the heat exchanger network are included in the present study. Using the data from an industrial plant, a complex FCC process simulator was built. The structure of the optimal heat exchange network (HEN) was designed and implemented in the simulator. Comparison between PID and MPC control strategy was done and the incentives of the proposed MPC are revealed.

Evaluation of the Use of Solids Waste Generated in the Activities of Exploration as Adsorbents for Treatment of Oil Derivatives

Currently, the biggest concern of different industries is the disposal of waste generated. The liquid effluents in general have more elaborate studies realizing alternatives for their treatment by reducing their toxicity or changing specifications for a return to the process, an internal recycling or even studying alternatives for recycling outside. In the case of solid waste, there are many papers on reuse. In general, the studies involve alternatives to reduce the possible toxicity and subsequent disposal. In some cases, the studies dealt with the residue already involve their use as material for construction (bricks). This work aims to evaluate two types of waste, namely, the drilling mud to clay-based generated by the activity of exploration and exploitation of oil and solid waste generated in the production process and catalyst for fluid catalytic cracking plant. In both cases, is currently the destination for industrial landfills, and the generating unit has to bear all expenses related to material handling. Our purpose in studying this waste, will initially study the temperature profiles. The dry material being ground and with a pre-determined size will be tested for physical-chemical, such as X-ray fluorescence (XRF) to see the composition and ASAP to analyze the surface area and pore volume. With this material treated in bench tests will be performed to assess the capability of removing nitrogen and sulfur contaminants in lighter fractions of petroleum. Preliminary tests with the industrial base of sorbent clay and zeolite showed a good result. These tests serve as a basis for comparison with material obtained in the laboratory.

Predictive Modeling of Large-Scale Integrated Refinery Reaction and Fractionation Systems from Plant Data. Part 2: Fluid Catalytic Cracking (FCC) Process

This work presents the methodology to develop, validate, and apply a predictive model for an integrated fluid catalytic cracking (FCC) process. We demonstrate the methodology using data from a commercial FCC plant in the Asia Pacific with a feed capacity of 800 000 tons per year. Our model accounts for the complex cracking kinetics in the riser–regenerator with a 21-lump kinetic model. We implement the methodology with Microsoft Excel spreadsheets and a commercial software tool, Aspen HYSYS/Petroleum Refining from Aspen Technology, Inc. The methodology is equally applicable to other commercial software tools. This model gives accurate predictions of key product yields and properties given feed qualities and operating conditions. In addition, this work presents the first lumped FCC kinetic model integrated with a gas plant model in the literature. We validate this work using 6 months of plant data. We also perform several case studies to show how refiners may apply this work to improve the gasoline yield a...

Novel SOx removal catalysts for the FCC process: Manufacture method, characterization, and pilot-scale testing

A novel method for preparing SOx removing (ReSOx) catalysts for the fluid catalytic cracking (FCC) process, based on multimetallic layered double hydroxides (LDHs), is presented. The synthesis procedure is industrially feasible and environmentally friendly. Ceria is incorporated in varying amounts as oxidation promoter, to obtain catalysts that are able to work efficiently in either partial or full combustion regenerator modes. The manufacturing process presented herein enables obtaining, by spray drying, microsphere particles with mechanical properties that are adequate for fluidization, without requiring addition of binding agents. The physicochemical properties of the catalysts are examined by several characterization techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). A uniform dispersion of the metal components is observed throughout the particles. Furthermore, the microspheroidal catalysts are tested for the reduction of SOx emissions in a pilot-scale FCC plant, circulating together with a conventional cracking catalyst, during the conversion of a sulphur-containing industrial gas oil obtained from a Mexican refinery. ReSOx catalyst addition to the pilot FCC unit, in only 0.2 wt% of the total catalyst inventory, results in a maximum %SO2reduction of 74–80%. Additionally, the effect of the ReSOx catalyst on the main cracking reactions is studied; it is shown that the disruption of the cracking catalyst's activity and selectivity is minimal, at a concentration of 1.5 wt% of the total catalyst inventory. Thus, the use of these SOx removal catalysts appears as a viable, low investment, flexible and effective option for in situreduction of SOx flue gas emissions.

SO2 Removal and Regeneration of MgO-Based Sorbents Promoted with Titanium Oxide

To improve the deactivation of the sorbent for the removal of SO2 in residue fluid catalytic cracking plants, a Ce−Fe−MgO sorbent with excellent sulfur removal capacity and regeneration ability was modified by adding new promoters such as Ti, Al, and Zr. The sorbents were prepared by a coprecipitation method, and their sulfur removal capacities and regeneration abilities were measured in a fixed-bed reactor during multiple cycles. In particular, the sulfur removal capacity of the CeFeMgTi sorbent showed a high absorption value (41.2 g of sulfur/g of absorbent × 100) and excellent regeneration ability during multiple cycles. These results can be explained by the difference in their crystal structures and the physical and textural properties.

Heat integration retrofit analysis of a heat exchanger network of a fluid catalytic cracking plant

The impact of a process system on environmental pollution has both a local and global effect. The performance of the heat exchanger network (HEN) in a plant is an important aspect of energy conservation. Pinch technology and its recent extensions offer an effective and practical method for designing the HEN for new and retrofit projects. The fluid catalytic cracking (FCC) is a dominant process in oil refineries and there has been a sustained effort to improve the efficiency and yield of the unit over the years. Nevertheless, benefits and scope for improvement can still be found. The HEN of the FCC process considered here consists of a main column and a gas concentration section. Appropriate data were extracted from the existing network, using flowsheeting simulation. The stream data consists of 23 hot and 11 cold streams and cost and economic data required for the analysis were specified. The incremental area efficiency methodology was used for the targeting stage of the design and the design was carried out using the network pinch method consisting of both a diagnosis and optimisation stage. In the diagnosis stage promising designs were generated using UMIST developed sprint software. The generated design was then optimised to trade-off capital cost and energy savings. The design options were compared and evaluated and the retrofit design suggested. The existing hot utility consumption of the process was 46.055 MW with a ΔT min of 24°C. The area efficiency of existing design was 0.805. The targeting stage using incremental area efficiency sets the minimum approach temperature at 11.5°C, thereby establishing the scope for potential energy savings. To achieve a practical project, the number of modifications is limited. The selected retrofit design has 8.955 MW saving – 74% of the whole scope. This corresponds to 27% utility cost savings with a payback period of 1.5 years. The modifications include addition of four heat exchanger units and repiping of one existing exchanger.

Design of a Turbomachine Set for a Fluid Catalytic Cracking Plant and Its Shop-Testing Under Full-Load Conditions

In fluid catalytic cracking plants, heavy hydrocarbons are converted into low-boiling point products. The highly developed technology of this process makes it particularly suitable for the handling of heavy fractions and thus for energy economy in the future. Starting from a concise description of the energy recovery system, this paper details the design features of a turbo machine set for an FCC plant, with the emphasis on the design of the four-stage 12,000 kW process gas expander. Since this expander incorporates new design features, an extensive test programme was carried out at a large turbomachinery test facility, where, in addition to testing the individual machine units under full-load conditions, a string test of the complete turbomachine set was performed under hot-gas conditions.