Statistical comparison of two remediation methods: Remedial nutrient solution and enhanced natural attenuation were analyzed in terms of TPH of different soil samples collected from Khana Local Government Area of Rive...Statistical comparison of two remediation methods: Remedial nutrient solution and enhanced natural attenuation were analyzed in terms of TPH of different soil samples collected from Khana Local Government Area of Rivers State, Nigeria at different locations and placed inside sample bottles labelled A to D and replicated into two, one for each of the above treatment technique. The TPH of the soil was determined using GC analyzer after solvent extraction was carried out using hexane/dichloromethane mixture. Three batches of treatment were performed on the samples at every interval of eight weeks for a duration of six months. The result obtained was analyzed using a two-way ANOVA factorial experimental design to test the significance of the various sources of variation. From the result obtained, source of variation for sample and interactions were non-significantly different from each other which means that irrespective of the number of samples analyzed or the combination of both samples and batches of treatment, they will still not be significantly different from each other. The source of variation for batch and replications were significantly different from each other and this means that irrespective of the batches of treatment applied or the number of replications (methods of treatment used), they will always be significantly different from each other. The individual comparison of each sample showed that the efficiency of the Remedial Nutrient Solution method was better than Enhanced Natural Attenuation method.展开更多
Heat exchanger is an important equipment used in process industries for cooling and heating purposes. Its design configuration which involves the flow of cold and hot fluids within the exchanger subjects it to corrosi...Heat exchanger is an important equipment used in process industries for cooling and heating purposes. Its design configuration which involves the flow of cold and hot fluids within the exchanger subjects it to corrosion attack. The article utilized the principle of mass and energy conservation in the development of weight and temperature models to study the effect of corrosion on mild steel coupon inside the exchanger containing water and Mono ethanol amine (MEA). The models developed were resolved analytically using Laplace Transform and simulated using Excel as simulation tool and data obtained from experiment in the laboratory to obtain profiles of weight loss and temperature as a function of time. The weight loss and performance of mild steel under various corrosive conditions were examined which indicates the effect of corrosion on the mild steel heat exchanger in water and MEA media. The result shows that water is more corrosive than MEA at higher temperatures and at lower temperatures of 35°C and 1 atm, MEA has inhibitive properties than water as indicated by the weight loss result with time. The comparative analysis between the results obtained from the model simulation and experimental results shows that the result obtained from the model is more reliable and demonstrated better performance characteristics as it clearly shows mild steel heat exchanger experiences more corrosive effect in water medium than MEA at higher temperatures. And at lower temperatures, MEA becomes more inhibitive and less corrosive than water. The model simulation results correlate with various literatures and hence, it is valid for future referencing.展开更多
Sorption characteristics of multiple adsorption of six heavy metal ions often found in refinery waste waters using activated carbon from Nigerian bamboo was investigated. The bamboo was cut, washed and dried. It was c...Sorption characteristics of multiple adsorption of six heavy metal ions often found in refinery waste waters using activated carbon from Nigerian bamboo was investigated. The bamboo was cut, washed and dried. It was carbonized between 350℃ - 500℃, and activated at 800℃ using nitric acid. Simultaneous batch adsorption of different heavy metal ions (Cd<sup>2+</sup>, Ni<sup>2+</sup>, Pb<sup>2+</sup>, Cr<sup>3+</sup>, Cu<sup>2+</sup> and Zn<sup>2+</sup>) in same aqueous solution using activated carbon from Nigerian bamboo was carried out. The adsorption process had a better fit for the Freundlich, Temkin isotherm and Dubinin-Radushke-vich (DRK) isotherm models but could not fit well into Langmuir isotherm. Adsorption isotherms showed that there is competition among various metals for adsorption sites on Nigerian bamboo. The DRK model was used to determine the nature of the sorption process and was found to be physical and chemical, with sorption energy of metal ions ranging from (7 - 10 kJ/mol). The adsorption of Cd<sup>2+</sup>, Zn<sup>2+</sup>, Pb<sup>2+</sup> and Ni<sup>2+</sup> ions was chemisorptions and that of Cu<sup>2+</sup> and Cr<sup>3+</sup> ions was cooperative adsorption. Therefore, this study revealed that Nigerian bamboo can serve as a good source of activated carbon with multiple and simultaneous metalions—removing potentials and may serve as a better replacement for commercial activated carbons in applications that warrant their use.展开更多
An HYSYS model for the crude distillation unit of the Port Harcourt Refining Company has been developed. The HYSYS model developed includes 3 mixers, 3 heaters, 1 heat exchanger, 1 desalter (3-phase separator), 2-phas...An HYSYS model for the crude distillation unit of the Port Harcourt Refining Company has been developed. The HYSYS model developed includes 3 mixers, 3 heaters, 1 heat exchanger, 1 desalter (3-phase separator), 2-phase separator and the main fractionating column. The raw crude was characterized using Aspen HYSYS version 8.8 and the developed model was simulated with the industrial plant data from the Port Harcourt Refining Company. The HYSYS model gave component mole fractions of 0.2677, 0.1572, 0.2687, 0.0547, 0.2517 for Naphtha, Kerosene, Light Diesel Oil (LDO), Heavy Diesel Oil (HDO) and Atmospheric Residue and when compared to plant mole fractions of 0.2710, 0.1560, 0.2650, 0.0530, 0.2550 gave a maximum deviation of 3.2%. The HYSYS model was also able to predict the temperature and the tray of withdrawal for Naphtha, Kerosene, Light Diesel Oil (LDO), Heavy Diesel Oil (HDO) and Atmospheric Residue as follows: tray 1 (120<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C), tray 12 (206<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C), tray 25 (215<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C), tray 35 (310<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C) and tray 48 (320<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C) which was also compared with plant data and gave a maximum deviation 23.2%. The HYSYS model was then optimized using Sequential Quadratic Programming (SQP) with the industrial plant data as starting values of operating conditions. The optimization increased the mass flow rate of Naphtha product from 7.512E+004 kg/hr to 7.656E+004 kg/hr, Kerosene product from 5.183E+004 kg/hr to 5.239E+004 kg/hr, Light Diesel Oil (LDO) product from 1.105E+005 kg/hr to 1.112E+005 kg/hr, Heavy Diesel Oil (HDO) from 2.969E+004 kg/hr to 2.977E+004 kg/hr while the last product being Atm Residue remained at 3.157E+005 kg/hr. The new optimum mole fraction values for the five products were as follows: 0.2713, 0.1540, 0.2635, 0.0528, and 0.2584 while corresponding optimum temperature values were as follows: 129<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C, 221<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C, 257<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C, 317<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C and 327<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C.展开更多
This work describes the development of a process to produce zeolite X from mined kaolin clay from Kono-Boue and Chokocho, Rivers State, Nigeria. The procedures involved the beneficiation of the raw kaolin and calcinat...This work describes the development of a process to produce zeolite X from mined kaolin clay from Kono-Boue and Chokocho, Rivers State, Nigeria. The procedures involved the beneficiation of the raw kaolin and calcinations at 850<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C, to transform the kaolin to a more reactive metakaolin. Afterwards, the extremely reactive metakaolin was purge with sulphuric acid to obtain the much needed silica-alumina ratio for zeolite X synthesis. An alkaline fusion stage was then carried out to transform the metakaolin into zeolite by mixing with aqueous NaOH to form gel then allowed to stay for a duration of seven days at room temperature. The samples were then charged into a propylene container and placed in an oven at a temperature of 100<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C for the reaction to take place for 6 h. Identification of the crystalline phases by X-ray Diffraction (XRD), chemical/elemental compositions by X-ray Fluorescence (XRF)/Energy Dispersive Spectroscopic analyses (EDS), surface morphology by Scanning Electron Microscopy (SEM) and molecular vibration of units by Fourier Transform Infrared Spectrophotometry (FT-IR) were done. The results showed that the zeolite synthesized from Chokocho kaolin (CK) was more crystalline/larger with sharper peaks on both XRD and FTIR than that from Kono-Boue. This was also supported by slightly rougher surface morphology of CK over KK on SEM. XRF Si:Al ratios of 10.73 and 14.36 were obtained for KK and CK respectively. EDS results supported the XRF ratios. Sharper zeolitic characteristic O-H stretching bands at 3488 and 3755 cm<sup>-1</sup> were recorded for CK than KK. However, both results showed that zeolite X have been produced from both Kono-Boue and Chokocho kaolin clays respectively.展开更多
A scheme that optimizes the converter of an ammonia synthesis plant to determine optimal inlet temperatures of the catalyst beds has been developed. The optimizer maximizes an objective function—The fractional conver...A scheme that optimizes the converter of an ammonia synthesis plant to determine optimal inlet temperatures of the catalyst beds has been developed. The optimizer maximizes an objective function—The fractional conversion of nitrogen on the four catalyst beds of the converter subject to variation of the inlet temperature to each catalyst bed. An iterative procedure was used to update the initial values of inlet temperature thus ensuring accurate results and quick convergence. Converter model results obtained with optimized operating conditions showed significant increase in fractional conversion of 42.38% (from 0.1949 to 0.2586), increased rate of reaction evident in a 13.18% (0.5317 to 0.4616) and 23.84% (0.1946 to 0.1482) reduction in reactants (hydrogen and nitrogen) concentration respectively and a 56.48% increase (from 0.1181 to 0.1838) in ammonia concentration at the end of the fourth catalyst bed compared to results obtained with industrial operating conditions.展开更多
Dispersion models for the simulation of an industrial Fluid Catalytic Cracking Riser Reactor have been developed. The models were developed based on the principle of conservation of mass and energy on the reacting spe...Dispersion models for the simulation of an industrial Fluid Catalytic Cracking Riser Reactor have been developed. The models were developed based on the principle of conservation of mass and energy on the reacting species due to bulk flow and axial dispersion. The four-lump kinetic scheme was used to describe the cracking reactions occurring in the reactor. The model equations were a set of parabolic Ordinary Differential Equations which were reduced to first order differential equations by appropriate substitutions and integrated numerically using 4th order Runge Kutta algorithm using Visual Basic 6.0. Results obtained showed a maximum percentage deviation ranging from 0.31% to 5.7% between model predictions and industrial plant data indicating reasonable agreement. Simulation of model at various operating parameters gave optimum gasoline yield of 45.6% of the most significant variable of temperature (658 K), superficial velocity (0.1 m/s), catalyst to gas oil ratio (7.0) and diffusion coefficient of 0.23 m2/s.展开更多
Boil-Off Gas creation and usage has been a source of worry in Liquefied Natural Gas value supply chain. BOG is generated when there is temperature gradient between the environment and LNG temperature within the carrie...Boil-Off Gas creation and usage has been a source of worry in Liquefied Natural Gas value supply chain. BOG is generated when there is temperature gradient between the environment and LNG temperature within the carrier tank, process lines or vessels. In this work, Computer Aided Design for the recovery of BOG from flare in an LNG Plant considered the dynamic nature of the BOG with minimized total energy consumption. A rigorous simulation based optimization model using HYSYS V8.8 was presented. Possible BOG scenarios were formulated in this report and considerations taken from the BOG scenarios to form the basic scope of this work. An Aspen HYSYS Software was used to develop a Process Flow Scheme (PFS) which was simulated using the BOG scenarios formulated. The BOG scenario temperatures considered were -15°C for Warm Ship analogy, -90°C for Cold Ship and -140°C for Normal Design Mode. Assumptions were also made on the feed into the developed PFS before quenching the various BOG temperatures. With HYSYS simulation at assumed constant inlet mass flow rate of 25,000 kg/s for BOG FEED, 6250 kg/s for LNG & LNG1 FEED, quenching at various BOG feed temperature -15°C, -90°C and -140°C, gave a meaningful output. The Mass flow rate recovered from Warm Ship at -15°C for Cold Product was 35,183 Kg/s and for Liquid Product 2317 Kg/s. For Cold ship at -90°C, the Cold Product recovered was 32,174 Kg/s and Liquid Product was 5326 Kg/s. Also, for -140°C, the Cold Product was 28,004 Kg/s and the Liquid Product was 9496 Kg/s. The Energy stream for the Compressor, Cooler and Pump in the Process Flow Stream (PFS) were observed in Table 5. At -15°C, the Compressor energy was 3.22E+07KJ/h, while the Pump energy was 3412KJ/h, and the Cooler gave 1.90E+07KJ/h. The results above showed that excessive BOG from Warm ship can be quenched and recovered for other end users rather than undue flaring of the gases. Extra work needs to be done to ensure minimal energy utilisation, optimal recovery and high efficiency of this developed model.展开更多
This work is detailed towards ascertaining the thermodynamics and kinetics considerations for the production of caustic soda from brine and soda ash. The thermodynamics considers the Gibbs free energy;which is the min...This work is detailed towards ascertaining the thermodynamics and kinetics considerations for the production of caustic soda from brine and soda ash. The thermodynamics considers the Gibbs free energy;which is the minimum electrical work that must be supplied to an electric cell to drive the electrochemical reactions and its relationship with other thermodynamic parameters. The kinetics aspect of this research deduces the reaction rate equations and also predicts via feasible calculations the rate of the reaction, rate constant and order of the reaction. The examination of the thermodynamic analysis shows that the reaction is exothermic, positive value of entropy indicates that there is intrinsic energy which can be converted into work by a perfect electrolytic reaction process. The work determines the extent and the rate of the production process of caustic soda production and as such a pilot plant production of caustic soda from naturally occurring seawater via the diaphragm cell may be developed. The results obtained have shown that the cell potential using the Nerst equation for the production of optimum product caustic soda are: E = 0.5232 volt and the reaction is of second order. The rate of the reaction r=6.264×10−12 mol⋅cm−2⋅s−1 and the rate constant K2=9.2591×10−5cm⋅s−1.展开更多
Gas flaring is concerned with the combustion of lighter ends of hydrocarbon mostly produced in association with crude oil. Flare networks are designed to handle the gas volume required to be flared. Most times, this f...Gas flaring is concerned with the combustion of lighter ends of hydrocarbon mostly produced in association with crude oil. Flare networks are designed to handle the gas volume required to be flared. Most times, this flare networks are in close proximity but still have independent flare stacks, increasing risk to environment and cost on infrastructures. There is a need to integrate the flare networks in facilities within same area and through the application of Pinch Analysis concept, the resultant flare network can be optimized to give a system having optimal tail and header pipe sizes that will reduce cost and imp</span><span style="font-family:Verdana;">act on environment. In the light of the foregoing, the conce</span><span style="font-family:Verdana;">pt of pinch analy</span><span style="font-family:Verdana;">sis was used in debottlenecking integrate</span><span style="font-family:Verdana;">d gas flare networks from a flow station and a refinery in close proximity. Both flare networks were integrated and the resultant gas flare network was optimized to obtain the optimum pipe header and tail pipe sizes with the capacity to withstand the inventory from both facilities and satisfy the set constraints such as Mach number, noise, RhoV</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and backpressure. Mach number was set at 0.7 for tail pipes and 0.5 for header pipes, noise limit was not to exceed 80 dB upstream and 115 dB downstream the sources, RhoV</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> was limited to 6000 kg/m/s</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and the back</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">press</span><span style="font-family:Verdana;">ure requirement was source dependent respectively. The</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">fir</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">e case scenario was considered, as it is the worst-case scenario in the studies. When pinch analysis was applied in debottlenecking the combined gas flare network, it g</span><span style="font-family:Verdana;">ave smaller tail and header pipe sizes which is more economical. A </span><span style="font-family:Verdana;">20% decrease in pipe sizes was recorded at the end of the study.展开更多
Membrane Bio Reactor (MBR) has been designed and simulation for the treatment of Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Organic Carbon (TOC), Total Dissolved Solid (TDS) and Oil/ Grease in p...Membrane Bio Reactor (MBR) has been designed and simulation for the treatment of Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Organic Carbon (TOC), Total Dissolved Solid (TDS) and Oil/ Grease in produced water at a capacity of 54.1778 kg/hr for removal of 95%-99% contaminants. The MBR design equations were developed using the law of conservation of mass to determine the dimensions and functional parameters. The developed performance equations were integrated numerically using fourth-order Runge-Kutta embedded in MATLAB computer program to determine the optimum range of values of the reactor functional dimensions and functional parameters. The effect of rate of energy supply per reactor volume and substrate specific rate constant on the capacity of the membrane bioreactor were investigated. Also, the effect of initial loading of substrate on Solid Retention Time (SRT) was also investigated. Results showed that kinetic parameters influenced the percentage removal of contaminants as Hydraulic Retention Time (HRT) and size of MBR decreased with increase in specific rate constant at fixed conversion of contaminants. Also, HRT and MBR size increased as the conversion of Chemical Oxygen Demand (COD) was increased, while increased in the ratio of energy supplied per volume resulted in decreased of MBR volume. The effect of initial loading of substrate on SRT showed that increased in substrate loading increased the retention time of the solid at fixed substrate conversion, while the conversion of substrate to microorganism increased as the solid retention time was increased. The increased in initial loading of substrate concentration increased the production of Mixed Liquor Suspended Solids (MLSS). Thus, the size of MBR required for the conversion of the investigated contaminants at the design percentage removal increased in the following order: oil/grease 3;0.98 and 4.68 m;and 1.38 and 6.62 at 95% and 99% respectively, while the SRT was 82.67 days.展开更多
Adsorption techniques using meshed groundnut husks and plantain peels have provided cheap alternative to the conventional methods of crude oil spillage control and also for good waste management approach. The biodegra...Adsorption techniques using meshed groundnut husks and plantain peels have provided cheap alternative to the conventional methods of crude oil spillage control and also for good waste management approach. The biodegradable nature of these adsorbents makes it a better alternative to the non biodegradable synthetic polymers. Dry unripe plantain peels and groundnut husks were used to prepare the adsorbents. The adsorption and percentage removal of crude oil from effluent produce water was dependent on adsorbent dosage, contact time,temperature and particle size. The particle size of the adsorbents should not be less than 150 μm to avoid making the particles so loosed thus posing difficulty in recovery. The two adsorbents exhibit high affinity for oil adsorption with time especially at 75 μm, groundnut husk has a better performance because of its larger surface area and the presence of residual oil in the plantain peels. Agitation at 150 r.min-1 and contact time between 15 - 75 min are recommended. The optimum adsorption temperature ranged between 25°C - 45°C and 15°C - 45°C for groundnut husks and plantain peels respectively. The adsorption data indicated that a pseudo-second- order equation could be used to study the adsorption kinetics of both adsorbents.展开更多
Nigerian crude oil type Okoro 2012 was applied in this study owing to its low API value 23.54 and high residual percentage value of 42.16% from conventional modular refinery operations in Nigeria. The residue acted as...Nigerian crude oil type Okoro 2012 was applied in this study owing to its low API value 23.54 and high residual percentage value of 42.16% from conventional modular refinery operations in Nigeria. The residue acted as a precursor or feedstock to the hydrocracker reactor of the modified modular refinery operation, which is an hydrogenation catalytic process at operating conditions of 380°C and 183 bar respectively and the hydrogen gas applied is produced via steam-methane reforming since the operational feedstocks are available as methane is the first gaseous product from the modified modular refinery process. Thus, more valuable products such as liquefied petroleum gas, naphtha and diesel were produced from modified modular refinery thereby resolving the residue or bottom product issue associated with conventional modular refinery operation in Nigeria. Models were developed from the first principle through the application of the principle of conservation of mass to predict the performance of the hydrocracker reactor and the developed models were sets of ordinary differential equations, which were solved using MatLab ODE45 solver and validated using simulation data of Aspen Hysys software for the hydrocracker reactor. The results gave a minimum percentage absolute error (deviation) between model predictions and Aspen Hysys results of 4.45%, 5.0% and 2.02% for liquefied petroleum gas, naphtha and diesel products respectively. Hence, the model developed predicted the output performance of the hydrocracker reactor very closely and was applied in studying or simulation of the effects of catalyst effectiveness factor on the overall performance of the hydrocracker reactor.展开更多
Iron (III) adsorption from aqueous solutions unto periwinkle shell carbon (PSC) was studied using batch experiments. Activated periwinkle shell carbon was prepared (pyrolysed at 300°C and activated with nitric ac...Iron (III) adsorption from aqueous solutions unto periwinkle shell carbon (PSC) was studied using batch experiments. Activated periwinkle shell carbon was prepared (pyrolysed at 300°C and activated with nitric acid) and characterized to determine its physiochemical properties. Batch adsorption experiments were conducted to investigate the effects of process parameters (contact time, particle size, carbon dosage and pH of stock solution) on adsorption rate. Adsorption kinetics was tested using pseudo first and second order models. Adsorption Isotherms were analyzed using the Langmuir, Freundlich and Temkin isotherms while Thermodynamics parameters such as Enthalpy change (ΔH°), Entropy change (ΔS°) and Gibbs-free energy change (ΔG°) were determined. Results showed that adsorption rate increase with increase in contact time, adsorbent dose and pH and decreased with increase in particle size. Batch adsorption Kinetics experiments revealed that the mechanism of adsorption followed pseudo-second-order kinetic model. Isotherm data showed that the Langmuir isotherm accurately described the adsorption data indicating that adsorption process was mainly monolayer on a homogeneous adsorbent surface. Thermodynamic parameters results showed that adsorption process was endothermic with Enthalpy change (ΔH°): 222.91 kJ/mol;a positive Entropy change (ΔS°) of 19.19 kJ/mol, indicating an increase in the degree of freedom (or disorder) of the adsorbed species and a negative Gibb’s free energy (ΔG°) at all temperature indicating that the adsorption process was spontaneous and favorable at high temperature.展开更多
The research was aimed at providing water for cooling recycled cyclohexane in polyethylene plant to 15°C. This research could be redounding to the benefit of polyethylene plants that are using solution based poly...The research was aimed at providing water for cooling recycled cyclohexane in polyethylene plant to 15°C. This research could be redounding to the benefit of polyethylene plants that are using solution based polymerization technique. A chiller unit of 630 T, which has compressor power input of 378.33 kW and can provide chilled water capable of cooling recycle cyclohexane to 15°C, was designed using Aspen Hysys version 7.1. Four different refrigerants were tested to know the best fit refrigerant for the design and the best among them was R134a. The designed chiller has a coefficient of performance of 6.3 and a capacity greater than that of the defective chiller (550 TR). Unlike the defective chiller, with the increased cooling capacity and corresponding increase in compressor power from 296 kW to 378.6 kW, it could discharge chilled water capable of cooling recycle cyclohexane from 38°C to 15°C without tripping of the unit. With this design, ethylene absorption rate could increase to 40 T/h. Evaporator and condenser were designed and duties were 2166.39 KJ/sec and 2544.72 KJ/sec respectively. A thermostatic expansion valve with flow coefficient of 46.17 gpm was designed. The designed suction and discharge pressure were 414 kpa and 1053 kpa respectively while condenser temperature of 40°C was used for the design. The cooling of recycle cyclohexane from 38°C to 15°C using the chilled water supplied by the designed chiller was simulated using Aspen Hysys.展开更多
This research study focused on the need to curb scarcity and importation of petroleum finished products in oil-producing nation Nigeria through the operation of conventional modular refineries in conjunction with majo...This research study focused on the need to curb scarcity and importation of petroleum finished products in oil-producing nation Nigeria through the operation of conventional modular refineries in conjunction with major refineries operating efficiently. Hence, the study focused on the suitability and operations of conventional modular refinery processes by considering twenty different types of Nigerian crude oil for crude oil assay analysis and classification using Aspen Hysys. The crude oil assay results categorized the twenty Nigerian crude oil types as light and medium sweet crude, while based on recovery volume percent at a true boiling point of 370℃, the twenty crude oil types were categorized into Group A (crude oil with recovery volume above 80%), Group B (crude oil with recovery volume between 70% and 79%) and Group C (crude oil with recovery volume below 70%) respectively. Besides, light and medium sweet oil types were simulated in a conventional modular refinery (topping plant) at different numbers of column trays (25, 29, 35, 40 and 48) to determine their product yield. Based on product yield and equipment costs at different numbers of tray columns, a modular refinery with twenty-nine column trays was applied in this study. Thus, twenty Nigerian crude oil types were simulated in a conventional modular refinery of 30,000 barrel per day capacity and twenty-nine column trays respectively to evaluate their product yield and tray compositions.展开更多
The simulation of a process plant for the production of propylene has been considered in this work. The reactor used for this research was a Continuous Stirred Tank Reactor (CSTR) which was deliberately picked because...The simulation of a process plant for the production of propylene has been considered in this work. The reactor used for this research was a Continuous Stirred Tank Reactor (CSTR) which was deliberately picked because of the advantage of good temperature and reaction control. Other equipment includes a compressor, conversion reactor, cooler and splitter. Sizing was done for all equipment but detailed design was carried out for the CSTR since it’s the heart of the process plant. The principle of conservation of mass was applied for the development of basic design performance equations for the volume, the height, space time, space velocity and heat generated per unit volume at 90% conversion of propane to propylene. Aspen Hysys which is known for its reliability in chemical engineering process design was used to simulate the process plant and was used for all calculations and sizing of process equipment. The values of the functional and dimensional parameters which are required for the sizing of the reactor were obtained after the simulation with the following results: volume of reactor 37 m3, height of reactor 7.4 m, space time 0.028 hr, space velocity 59 hr<sup><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">-</span>1</sup> and heat load 78 kj/m<sup>3</sup>.展开更多
The simulation of a 270 KTA capacity polyethylene plant was performed using Aspen Hysys version 8.8. A Hysys model of the polyethylene was developed using the polyethylene plant layout of Indorama Eleme Petrochemical ...The simulation of a 270 KTA capacity polyethylene plant was performed using Aspen Hysys version 8.8. A Hysys model of the polyethylene was developed using the polyethylene plant layout of Indorama Eleme Petrochemical Company. A material and energy balance for the various components of the plant was performed manually and with Hysys for comparison. The design of the various components of the Hysys model was performed. The polyethylene reactor was simulated to study the effect of process functional parameters such as reactor dimensions, temperature and pressure. The effect of reactor size and number on polyethylene output was studied by simulating the plant with five continuous stirred tank reactors (CSTRs) in series and a single reactor. The results of the material and energy balance of the various components of the plant were performed manually and with Hysys which showed a maximum deviation of 0.8%. The design results of the sizing parameters for the Multiple and single CSTRs were compared in terms of Volume, Diameter, Height, Spacetime, Space Velocity, and Volumetric flowrate respectively. At 90% Conversion, the multiple CSTRs gave 600 dm<sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 0.7668 m, 1.198 m, 0.052 hr, 195.83 hr</span><sup><span style="color:#4F4F4F;font-family:Verdana;">-</span><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">, and 117.5 m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">/h for the above listed parameters, while the single CSTR gave 6000 dm</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 1.721 m, 2.581 m, 0.056 hr, 17.867 hr</span><sup><span style="color:#4F4F4F;font-family:Verdana;">-</span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> and 107.2 m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">/h for the same conversion. The sizing results for each of the five compressors were also compared in terms of the following parameters: Adiabatic Head, Polytropic Head, Adiabatic fluid Head, polytropic Fluid Head, Adiabatic Efficiency, power consumed, polytropic head factor, polytropic exponent and isentropic exponent. The effect of reactor size and number showed that At 90% conversion the multiple CSTRS in series gave a lower volume than the single CSTR for the same conversion, and more Economical than the single CSTR for the same conversion.</span>展开更多
Dynamic Models for predicting the concentration profiles of the reactants and product in a Continuous Stirred Tank Reactor for the transesterification of used cooking oil (triglyceride) to biodiesel has been developed...Dynamic Models for predicting the concentration profiles of the reactants and product in a Continuous Stirred Tank Reactor for the transesterification of used cooking oil (triglyceride) to biodiesel has been developed using the principle of conservation of mass. The developed system of differential equations were integrated numerically using fourth order Runge-Kutta algorithm embedded in ode 45 solver of 7.5 Mathlab program. The models were validated by solving the model equations with kinetic data and other relevant data from literatures. The results and trends were similar and in agreement with those from these literatures. Simulations of the reactor to (±) step changes in the inlet flowrates of the reactants (used cooking oil and methanol) showed great effect on biodiesel production, (instability—oscillations and reduction in output concentration of biodiesel). A feedback control strategy was developed with a Proportional-Integral (PI) Controller and a close loop model was developed for control studies. The closed loop response of the reactor output (biodiesel concentration) showed continuous oscillatory response with offset. Hence the controller parameters (proportional gain <em>K</em><em><sub>c</sub></em> and integral time <img src="Edit_b22777c4-287e-4ff4-a82a-0b5c9393b5ab.bmp" alt="" />) were tuned using the “On-Line Trial and Error Method” implemented using MathLab Simulink to obtain optimum values that ensured quick stability of the closed-loop system, reduced or no oscillatory response and no offset. The optimum controller parameters were: proportional gain <em style="white-space:normal;">K</em><em style="white-space:normal;"><sub>c</sub></em> =8.306 and integral time <img src="Edit_7ad87ff7-7563-48b0-865b-70efc6c433cd.bmp" alt="" />= 17.157 minutes. <p> <br /> </p>展开更多
The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. A...The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. Appropriate first-order model equations were developed applying principles of energy balance. The differential equations developed for the process streams which exchanged heat was evaluated numerically to predict the temperature variations as a function of time. The relevant parameters associated with typical heat exchanger works were calculated using plant data of 10-E-02. The model strives to predict the final kerosene temperature from 488 to 353.6 K. While the crude oil streams temperature rose from 313 to 353.6 K. The developed model enables the operator to predict the final temperature at the kerosene hydro-treating unit and thereby prevent regular emergency shutdowns due to excessive temperature rise.展开更多
文摘Statistical comparison of two remediation methods: Remedial nutrient solution and enhanced natural attenuation were analyzed in terms of TPH of different soil samples collected from Khana Local Government Area of Rivers State, Nigeria at different locations and placed inside sample bottles labelled A to D and replicated into two, one for each of the above treatment technique. The TPH of the soil was determined using GC analyzer after solvent extraction was carried out using hexane/dichloromethane mixture. Three batches of treatment were performed on the samples at every interval of eight weeks for a duration of six months. The result obtained was analyzed using a two-way ANOVA factorial experimental design to test the significance of the various sources of variation. From the result obtained, source of variation for sample and interactions were non-significantly different from each other which means that irrespective of the number of samples analyzed or the combination of both samples and batches of treatment, they will still not be significantly different from each other. The source of variation for batch and replications were significantly different from each other and this means that irrespective of the batches of treatment applied or the number of replications (methods of treatment used), they will always be significantly different from each other. The individual comparison of each sample showed that the efficiency of the Remedial Nutrient Solution method was better than Enhanced Natural Attenuation method.
文摘Heat exchanger is an important equipment used in process industries for cooling and heating purposes. Its design configuration which involves the flow of cold and hot fluids within the exchanger subjects it to corrosion attack. The article utilized the principle of mass and energy conservation in the development of weight and temperature models to study the effect of corrosion on mild steel coupon inside the exchanger containing water and Mono ethanol amine (MEA). The models developed were resolved analytically using Laplace Transform and simulated using Excel as simulation tool and data obtained from experiment in the laboratory to obtain profiles of weight loss and temperature as a function of time. The weight loss and performance of mild steel under various corrosive conditions were examined which indicates the effect of corrosion on the mild steel heat exchanger in water and MEA media. The result shows that water is more corrosive than MEA at higher temperatures and at lower temperatures of 35°C and 1 atm, MEA has inhibitive properties than water as indicated by the weight loss result with time. The comparative analysis between the results obtained from the model simulation and experimental results shows that the result obtained from the model is more reliable and demonstrated better performance characteristics as it clearly shows mild steel heat exchanger experiences more corrosive effect in water medium than MEA at higher temperatures. And at lower temperatures, MEA becomes more inhibitive and less corrosive than water. The model simulation results correlate with various literatures and hence, it is valid for future referencing.
文摘Sorption characteristics of multiple adsorption of six heavy metal ions often found in refinery waste waters using activated carbon from Nigerian bamboo was investigated. The bamboo was cut, washed and dried. It was carbonized between 350℃ - 500℃, and activated at 800℃ using nitric acid. Simultaneous batch adsorption of different heavy metal ions (Cd<sup>2+</sup>, Ni<sup>2+</sup>, Pb<sup>2+</sup>, Cr<sup>3+</sup>, Cu<sup>2+</sup> and Zn<sup>2+</sup>) in same aqueous solution using activated carbon from Nigerian bamboo was carried out. The adsorption process had a better fit for the Freundlich, Temkin isotherm and Dubinin-Radushke-vich (DRK) isotherm models but could not fit well into Langmuir isotherm. Adsorption isotherms showed that there is competition among various metals for adsorption sites on Nigerian bamboo. The DRK model was used to determine the nature of the sorption process and was found to be physical and chemical, with sorption energy of metal ions ranging from (7 - 10 kJ/mol). The adsorption of Cd<sup>2+</sup>, Zn<sup>2+</sup>, Pb<sup>2+</sup> and Ni<sup>2+</sup> ions was chemisorptions and that of Cu<sup>2+</sup> and Cr<sup>3+</sup> ions was cooperative adsorption. Therefore, this study revealed that Nigerian bamboo can serve as a good source of activated carbon with multiple and simultaneous metalions—removing potentials and may serve as a better replacement for commercial activated carbons in applications that warrant their use.
文摘An HYSYS model for the crude distillation unit of the Port Harcourt Refining Company has been developed. The HYSYS model developed includes 3 mixers, 3 heaters, 1 heat exchanger, 1 desalter (3-phase separator), 2-phase separator and the main fractionating column. The raw crude was characterized using Aspen HYSYS version 8.8 and the developed model was simulated with the industrial plant data from the Port Harcourt Refining Company. The HYSYS model gave component mole fractions of 0.2677, 0.1572, 0.2687, 0.0547, 0.2517 for Naphtha, Kerosene, Light Diesel Oil (LDO), Heavy Diesel Oil (HDO) and Atmospheric Residue and when compared to plant mole fractions of 0.2710, 0.1560, 0.2650, 0.0530, 0.2550 gave a maximum deviation of 3.2%. The HYSYS model was also able to predict the temperature and the tray of withdrawal for Naphtha, Kerosene, Light Diesel Oil (LDO), Heavy Diesel Oil (HDO) and Atmospheric Residue as follows: tray 1 (120<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C), tray 12 (206<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C), tray 25 (215<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C), tray 35 (310<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C) and tray 48 (320<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C) which was also compared with plant data and gave a maximum deviation 23.2%. The HYSYS model was then optimized using Sequential Quadratic Programming (SQP) with the industrial plant data as starting values of operating conditions. The optimization increased the mass flow rate of Naphtha product from 7.512E+004 kg/hr to 7.656E+004 kg/hr, Kerosene product from 5.183E+004 kg/hr to 5.239E+004 kg/hr, Light Diesel Oil (LDO) product from 1.105E+005 kg/hr to 1.112E+005 kg/hr, Heavy Diesel Oil (HDO) from 2.969E+004 kg/hr to 2.977E+004 kg/hr while the last product being Atm Residue remained at 3.157E+005 kg/hr. The new optimum mole fraction values for the five products were as follows: 0.2713, 0.1540, 0.2635, 0.0528, and 0.2584 while corresponding optimum temperature values were as follows: 129<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C, 221<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C, 257<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C, 317<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C and 327<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C.
文摘This work describes the development of a process to produce zeolite X from mined kaolin clay from Kono-Boue and Chokocho, Rivers State, Nigeria. The procedures involved the beneficiation of the raw kaolin and calcinations at 850<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C, to transform the kaolin to a more reactive metakaolin. Afterwards, the extremely reactive metakaolin was purge with sulphuric acid to obtain the much needed silica-alumina ratio for zeolite X synthesis. An alkaline fusion stage was then carried out to transform the metakaolin into zeolite by mixing with aqueous NaOH to form gel then allowed to stay for a duration of seven days at room temperature. The samples were then charged into a propylene container and placed in an oven at a temperature of 100<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C for the reaction to take place for 6 h. Identification of the crystalline phases by X-ray Diffraction (XRD), chemical/elemental compositions by X-ray Fluorescence (XRF)/Energy Dispersive Spectroscopic analyses (EDS), surface morphology by Scanning Electron Microscopy (SEM) and molecular vibration of units by Fourier Transform Infrared Spectrophotometry (FT-IR) were done. The results showed that the zeolite synthesized from Chokocho kaolin (CK) was more crystalline/larger with sharper peaks on both XRD and FTIR than that from Kono-Boue. This was also supported by slightly rougher surface morphology of CK over KK on SEM. XRF Si:Al ratios of 10.73 and 14.36 were obtained for KK and CK respectively. EDS results supported the XRF ratios. Sharper zeolitic characteristic O-H stretching bands at 3488 and 3755 cm<sup>-1</sup> were recorded for CK than KK. However, both results showed that zeolite X have been produced from both Kono-Boue and Chokocho kaolin clays respectively.
文摘A scheme that optimizes the converter of an ammonia synthesis plant to determine optimal inlet temperatures of the catalyst beds has been developed. The optimizer maximizes an objective function—The fractional conversion of nitrogen on the four catalyst beds of the converter subject to variation of the inlet temperature to each catalyst bed. An iterative procedure was used to update the initial values of inlet temperature thus ensuring accurate results and quick convergence. Converter model results obtained with optimized operating conditions showed significant increase in fractional conversion of 42.38% (from 0.1949 to 0.2586), increased rate of reaction evident in a 13.18% (0.5317 to 0.4616) and 23.84% (0.1946 to 0.1482) reduction in reactants (hydrogen and nitrogen) concentration respectively and a 56.48% increase (from 0.1181 to 0.1838) in ammonia concentration at the end of the fourth catalyst bed compared to results obtained with industrial operating conditions.
文摘Dispersion models for the simulation of an industrial Fluid Catalytic Cracking Riser Reactor have been developed. The models were developed based on the principle of conservation of mass and energy on the reacting species due to bulk flow and axial dispersion. The four-lump kinetic scheme was used to describe the cracking reactions occurring in the reactor. The model equations were a set of parabolic Ordinary Differential Equations which were reduced to first order differential equations by appropriate substitutions and integrated numerically using 4th order Runge Kutta algorithm using Visual Basic 6.0. Results obtained showed a maximum percentage deviation ranging from 0.31% to 5.7% between model predictions and industrial plant data indicating reasonable agreement. Simulation of model at various operating parameters gave optimum gasoline yield of 45.6% of the most significant variable of temperature (658 K), superficial velocity (0.1 m/s), catalyst to gas oil ratio (7.0) and diffusion coefficient of 0.23 m2/s.
文摘Boil-Off Gas creation and usage has been a source of worry in Liquefied Natural Gas value supply chain. BOG is generated when there is temperature gradient between the environment and LNG temperature within the carrier tank, process lines or vessels. In this work, Computer Aided Design for the recovery of BOG from flare in an LNG Plant considered the dynamic nature of the BOG with minimized total energy consumption. A rigorous simulation based optimization model using HYSYS V8.8 was presented. Possible BOG scenarios were formulated in this report and considerations taken from the BOG scenarios to form the basic scope of this work. An Aspen HYSYS Software was used to develop a Process Flow Scheme (PFS) which was simulated using the BOG scenarios formulated. The BOG scenario temperatures considered were -15°C for Warm Ship analogy, -90°C for Cold Ship and -140°C for Normal Design Mode. Assumptions were also made on the feed into the developed PFS before quenching the various BOG temperatures. With HYSYS simulation at assumed constant inlet mass flow rate of 25,000 kg/s for BOG FEED, 6250 kg/s for LNG & LNG1 FEED, quenching at various BOG feed temperature -15°C, -90°C and -140°C, gave a meaningful output. The Mass flow rate recovered from Warm Ship at -15°C for Cold Product was 35,183 Kg/s and for Liquid Product 2317 Kg/s. For Cold ship at -90°C, the Cold Product recovered was 32,174 Kg/s and Liquid Product was 5326 Kg/s. Also, for -140°C, the Cold Product was 28,004 Kg/s and the Liquid Product was 9496 Kg/s. The Energy stream for the Compressor, Cooler and Pump in the Process Flow Stream (PFS) were observed in Table 5. At -15°C, the Compressor energy was 3.22E+07KJ/h, while the Pump energy was 3412KJ/h, and the Cooler gave 1.90E+07KJ/h. The results above showed that excessive BOG from Warm ship can be quenched and recovered for other end users rather than undue flaring of the gases. Extra work needs to be done to ensure minimal energy utilisation, optimal recovery and high efficiency of this developed model.
文摘This work is detailed towards ascertaining the thermodynamics and kinetics considerations for the production of caustic soda from brine and soda ash. The thermodynamics considers the Gibbs free energy;which is the minimum electrical work that must be supplied to an electric cell to drive the electrochemical reactions and its relationship with other thermodynamic parameters. The kinetics aspect of this research deduces the reaction rate equations and also predicts via feasible calculations the rate of the reaction, rate constant and order of the reaction. The examination of the thermodynamic analysis shows that the reaction is exothermic, positive value of entropy indicates that there is intrinsic energy which can be converted into work by a perfect electrolytic reaction process. The work determines the extent and the rate of the production process of caustic soda production and as such a pilot plant production of caustic soda from naturally occurring seawater via the diaphragm cell may be developed. The results obtained have shown that the cell potential using the Nerst equation for the production of optimum product caustic soda are: E = 0.5232 volt and the reaction is of second order. The rate of the reaction r=6.264×10−12 mol⋅cm−2⋅s−1 and the rate constant K2=9.2591×10−5cm⋅s−1.
文摘Gas flaring is concerned with the combustion of lighter ends of hydrocarbon mostly produced in association with crude oil. Flare networks are designed to handle the gas volume required to be flared. Most times, this flare networks are in close proximity but still have independent flare stacks, increasing risk to environment and cost on infrastructures. There is a need to integrate the flare networks in facilities within same area and through the application of Pinch Analysis concept, the resultant flare network can be optimized to give a system having optimal tail and header pipe sizes that will reduce cost and imp</span><span style="font-family:Verdana;">act on environment. In the light of the foregoing, the conce</span><span style="font-family:Verdana;">pt of pinch analy</span><span style="font-family:Verdana;">sis was used in debottlenecking integrate</span><span style="font-family:Verdana;">d gas flare networks from a flow station and a refinery in close proximity. Both flare networks were integrated and the resultant gas flare network was optimized to obtain the optimum pipe header and tail pipe sizes with the capacity to withstand the inventory from both facilities and satisfy the set constraints such as Mach number, noise, RhoV</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and backpressure. Mach number was set at 0.7 for tail pipes and 0.5 for header pipes, noise limit was not to exceed 80 dB upstream and 115 dB downstream the sources, RhoV</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> was limited to 6000 kg/m/s</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and the back</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">press</span><span style="font-family:Verdana;">ure requirement was source dependent respectively. The</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">fir</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">e case scenario was considered, as it is the worst-case scenario in the studies. When pinch analysis was applied in debottlenecking the combined gas flare network, it g</span><span style="font-family:Verdana;">ave smaller tail and header pipe sizes which is more economical. A </span><span style="font-family:Verdana;">20% decrease in pipe sizes was recorded at the end of the study.
文摘Membrane Bio Reactor (MBR) has been designed and simulation for the treatment of Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Organic Carbon (TOC), Total Dissolved Solid (TDS) and Oil/ Grease in produced water at a capacity of 54.1778 kg/hr for removal of 95%-99% contaminants. The MBR design equations were developed using the law of conservation of mass to determine the dimensions and functional parameters. The developed performance equations were integrated numerically using fourth-order Runge-Kutta embedded in MATLAB computer program to determine the optimum range of values of the reactor functional dimensions and functional parameters. The effect of rate of energy supply per reactor volume and substrate specific rate constant on the capacity of the membrane bioreactor were investigated. Also, the effect of initial loading of substrate on Solid Retention Time (SRT) was also investigated. Results showed that kinetic parameters influenced the percentage removal of contaminants as Hydraulic Retention Time (HRT) and size of MBR decreased with increase in specific rate constant at fixed conversion of contaminants. Also, HRT and MBR size increased as the conversion of Chemical Oxygen Demand (COD) was increased, while increased in the ratio of energy supplied per volume resulted in decreased of MBR volume. The effect of initial loading of substrate on SRT showed that increased in substrate loading increased the retention time of the solid at fixed substrate conversion, while the conversion of substrate to microorganism increased as the solid retention time was increased. The increased in initial loading of substrate concentration increased the production of Mixed Liquor Suspended Solids (MLSS). Thus, the size of MBR required for the conversion of the investigated contaminants at the design percentage removal increased in the following order: oil/grease 3;0.98 and 4.68 m;and 1.38 and 6.62 at 95% and 99% respectively, while the SRT was 82.67 days.
文摘Adsorption techniques using meshed groundnut husks and plantain peels have provided cheap alternative to the conventional methods of crude oil spillage control and also for good waste management approach. The biodegradable nature of these adsorbents makes it a better alternative to the non biodegradable synthetic polymers. Dry unripe plantain peels and groundnut husks were used to prepare the adsorbents. The adsorption and percentage removal of crude oil from effluent produce water was dependent on adsorbent dosage, contact time,temperature and particle size. The particle size of the adsorbents should not be less than 150 μm to avoid making the particles so loosed thus posing difficulty in recovery. The two adsorbents exhibit high affinity for oil adsorption with time especially at 75 μm, groundnut husk has a better performance because of its larger surface area and the presence of residual oil in the plantain peels. Agitation at 150 r.min-1 and contact time between 15 - 75 min are recommended. The optimum adsorption temperature ranged between 25°C - 45°C and 15°C - 45°C for groundnut husks and plantain peels respectively. The adsorption data indicated that a pseudo-second- order equation could be used to study the adsorption kinetics of both adsorbents.
文摘Nigerian crude oil type Okoro 2012 was applied in this study owing to its low API value 23.54 and high residual percentage value of 42.16% from conventional modular refinery operations in Nigeria. The residue acted as a precursor or feedstock to the hydrocracker reactor of the modified modular refinery operation, which is an hydrogenation catalytic process at operating conditions of 380°C and 183 bar respectively and the hydrogen gas applied is produced via steam-methane reforming since the operational feedstocks are available as methane is the first gaseous product from the modified modular refinery process. Thus, more valuable products such as liquefied petroleum gas, naphtha and diesel were produced from modified modular refinery thereby resolving the residue or bottom product issue associated with conventional modular refinery operation in Nigeria. Models were developed from the first principle through the application of the principle of conservation of mass to predict the performance of the hydrocracker reactor and the developed models were sets of ordinary differential equations, which were solved using MatLab ODE45 solver and validated using simulation data of Aspen Hysys software for the hydrocracker reactor. The results gave a minimum percentage absolute error (deviation) between model predictions and Aspen Hysys results of 4.45%, 5.0% and 2.02% for liquefied petroleum gas, naphtha and diesel products respectively. Hence, the model developed predicted the output performance of the hydrocracker reactor very closely and was applied in studying or simulation of the effects of catalyst effectiveness factor on the overall performance of the hydrocracker reactor.
文摘Iron (III) adsorption from aqueous solutions unto periwinkle shell carbon (PSC) was studied using batch experiments. Activated periwinkle shell carbon was prepared (pyrolysed at 300°C and activated with nitric acid) and characterized to determine its physiochemical properties. Batch adsorption experiments were conducted to investigate the effects of process parameters (contact time, particle size, carbon dosage and pH of stock solution) on adsorption rate. Adsorption kinetics was tested using pseudo first and second order models. Adsorption Isotherms were analyzed using the Langmuir, Freundlich and Temkin isotherms while Thermodynamics parameters such as Enthalpy change (ΔH°), Entropy change (ΔS°) and Gibbs-free energy change (ΔG°) were determined. Results showed that adsorption rate increase with increase in contact time, adsorbent dose and pH and decreased with increase in particle size. Batch adsorption Kinetics experiments revealed that the mechanism of adsorption followed pseudo-second-order kinetic model. Isotherm data showed that the Langmuir isotherm accurately described the adsorption data indicating that adsorption process was mainly monolayer on a homogeneous adsorbent surface. Thermodynamic parameters results showed that adsorption process was endothermic with Enthalpy change (ΔH°): 222.91 kJ/mol;a positive Entropy change (ΔS°) of 19.19 kJ/mol, indicating an increase in the degree of freedom (or disorder) of the adsorbed species and a negative Gibb’s free energy (ΔG°) at all temperature indicating that the adsorption process was spontaneous and favorable at high temperature.
文摘The research was aimed at providing water for cooling recycled cyclohexane in polyethylene plant to 15°C. This research could be redounding to the benefit of polyethylene plants that are using solution based polymerization technique. A chiller unit of 630 T, which has compressor power input of 378.33 kW and can provide chilled water capable of cooling recycle cyclohexane to 15°C, was designed using Aspen Hysys version 7.1. Four different refrigerants were tested to know the best fit refrigerant for the design and the best among them was R134a. The designed chiller has a coefficient of performance of 6.3 and a capacity greater than that of the defective chiller (550 TR). Unlike the defective chiller, with the increased cooling capacity and corresponding increase in compressor power from 296 kW to 378.6 kW, it could discharge chilled water capable of cooling recycle cyclohexane from 38°C to 15°C without tripping of the unit. With this design, ethylene absorption rate could increase to 40 T/h. Evaporator and condenser were designed and duties were 2166.39 KJ/sec and 2544.72 KJ/sec respectively. A thermostatic expansion valve with flow coefficient of 46.17 gpm was designed. The designed suction and discharge pressure were 414 kpa and 1053 kpa respectively while condenser temperature of 40°C was used for the design. The cooling of recycle cyclohexane from 38°C to 15°C using the chilled water supplied by the designed chiller was simulated using Aspen Hysys.
文摘This research study focused on the need to curb scarcity and importation of petroleum finished products in oil-producing nation Nigeria through the operation of conventional modular refineries in conjunction with major refineries operating efficiently. Hence, the study focused on the suitability and operations of conventional modular refinery processes by considering twenty different types of Nigerian crude oil for crude oil assay analysis and classification using Aspen Hysys. The crude oil assay results categorized the twenty Nigerian crude oil types as light and medium sweet crude, while based on recovery volume percent at a true boiling point of 370℃, the twenty crude oil types were categorized into Group A (crude oil with recovery volume above 80%), Group B (crude oil with recovery volume between 70% and 79%) and Group C (crude oil with recovery volume below 70%) respectively. Besides, light and medium sweet oil types were simulated in a conventional modular refinery (topping plant) at different numbers of column trays (25, 29, 35, 40 and 48) to determine their product yield. Based on product yield and equipment costs at different numbers of tray columns, a modular refinery with twenty-nine column trays was applied in this study. Thus, twenty Nigerian crude oil types were simulated in a conventional modular refinery of 30,000 barrel per day capacity and twenty-nine column trays respectively to evaluate their product yield and tray compositions.
文摘The simulation of a process plant for the production of propylene has been considered in this work. The reactor used for this research was a Continuous Stirred Tank Reactor (CSTR) which was deliberately picked because of the advantage of good temperature and reaction control. Other equipment includes a compressor, conversion reactor, cooler and splitter. Sizing was done for all equipment but detailed design was carried out for the CSTR since it’s the heart of the process plant. The principle of conservation of mass was applied for the development of basic design performance equations for the volume, the height, space time, space velocity and heat generated per unit volume at 90% conversion of propane to propylene. Aspen Hysys which is known for its reliability in chemical engineering process design was used to simulate the process plant and was used for all calculations and sizing of process equipment. The values of the functional and dimensional parameters which are required for the sizing of the reactor were obtained after the simulation with the following results: volume of reactor 37 m3, height of reactor 7.4 m, space time 0.028 hr, space velocity 59 hr<sup><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">-</span>1</sup> and heat load 78 kj/m<sup>3</sup>.
文摘The simulation of a 270 KTA capacity polyethylene plant was performed using Aspen Hysys version 8.8. A Hysys model of the polyethylene was developed using the polyethylene plant layout of Indorama Eleme Petrochemical Company. A material and energy balance for the various components of the plant was performed manually and with Hysys for comparison. The design of the various components of the Hysys model was performed. The polyethylene reactor was simulated to study the effect of process functional parameters such as reactor dimensions, temperature and pressure. The effect of reactor size and number on polyethylene output was studied by simulating the plant with five continuous stirred tank reactors (CSTRs) in series and a single reactor. The results of the material and energy balance of the various components of the plant were performed manually and with Hysys which showed a maximum deviation of 0.8%. The design results of the sizing parameters for the Multiple and single CSTRs were compared in terms of Volume, Diameter, Height, Spacetime, Space Velocity, and Volumetric flowrate respectively. At 90% Conversion, the multiple CSTRs gave 600 dm<sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 0.7668 m, 1.198 m, 0.052 hr, 195.83 hr</span><sup><span style="color:#4F4F4F;font-family:Verdana;">-</span><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">, and 117.5 m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">/h for the above listed parameters, while the single CSTR gave 6000 dm</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 1.721 m, 2.581 m, 0.056 hr, 17.867 hr</span><sup><span style="color:#4F4F4F;font-family:Verdana;">-</span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;"> and 107.2 m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">/h for the same conversion. The sizing results for each of the five compressors were also compared in terms of the following parameters: Adiabatic Head, Polytropic Head, Adiabatic fluid Head, polytropic Fluid Head, Adiabatic Efficiency, power consumed, polytropic head factor, polytropic exponent and isentropic exponent. The effect of reactor size and number showed that At 90% conversion the multiple CSTRS in series gave a lower volume than the single CSTR for the same conversion, and more Economical than the single CSTR for the same conversion.</span>
文摘Dynamic Models for predicting the concentration profiles of the reactants and product in a Continuous Stirred Tank Reactor for the transesterification of used cooking oil (triglyceride) to biodiesel has been developed using the principle of conservation of mass. The developed system of differential equations were integrated numerically using fourth order Runge-Kutta algorithm embedded in ode 45 solver of 7.5 Mathlab program. The models were validated by solving the model equations with kinetic data and other relevant data from literatures. The results and trends were similar and in agreement with those from these literatures. Simulations of the reactor to (±) step changes in the inlet flowrates of the reactants (used cooking oil and methanol) showed great effect on biodiesel production, (instability—oscillations and reduction in output concentration of biodiesel). A feedback control strategy was developed with a Proportional-Integral (PI) Controller and a close loop model was developed for control studies. The closed loop response of the reactor output (biodiesel concentration) showed continuous oscillatory response with offset. Hence the controller parameters (proportional gain <em>K</em><em><sub>c</sub></em> and integral time <img src="Edit_b22777c4-287e-4ff4-a82a-0b5c9393b5ab.bmp" alt="" />) were tuned using the “On-Line Trial and Error Method” implemented using MathLab Simulink to obtain optimum values that ensured quick stability of the closed-loop system, reduced or no oscillatory response and no offset. The optimum controller parameters were: proportional gain <em style="white-space:normal;">K</em><em style="white-space:normal;"><sub>c</sub></em> =8.306 and integral time <img src="Edit_7ad87ff7-7563-48b0-865b-70efc6c433cd.bmp" alt="" />= 17.157 minutes. <p> <br /> </p>
文摘The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. Appropriate first-order model equations were developed applying principles of energy balance. The differential equations developed for the process streams which exchanged heat was evaluated numerically to predict the temperature variations as a function of time. The relevant parameters associated with typical heat exchanger works were calculated using plant data of 10-E-02. The model strives to predict the final kerosene temperature from 488 to 353.6 K. While the crude oil streams temperature rose from 313 to 353.6 K. The developed model enables the operator to predict the final temperature at the kerosene hydro-treating unit and thereby prevent regular emergency shutdowns due to excessive temperature rise.
