Changes In Feed Flow Rate Research Articles

Plantwide Control: A New Design Procedure and Its Application at Liquefied Petroleum Gas Facility (LPGF) Plant

Natural Gas is the cleanest source of fossil energy, resulting in lower carbon emissions from coal and oil. In gas processing, the process done to separate the product composition is the fractionation process. In the gas industry, facilities/parts that are specifically to perform the process are called liquefied petroleum gas Facility plant (LPGF). Process Control is the key to a safe and profitable process industry. The Plantwide control is a structural design and control strategy for the factory as a whole. The preferred control method on this final task is the PID for regulatory control as well as the decentralized supervisory control for supervisory control and the real time optimizer for its optimization. The new plantwide control procedure can increase the profit in the process liquefied petroleum gas facility plant up to USD 643 h–1 (3 %) and decreased energy use by USD 5 h–1 (5.16 %). The application of the Plantwide control on the liquefied petroleum gas facility is also able to produce a stable system response when the interruption of the feed flow rate changes. This is demonstrated by decreasing slurries time and maximum overshoot as well as eliminating steady-state errors.

Enrichment effects at different control algorithms in jig in the presence of feed flow rate changes

The article describes selected PI digital control algorithms. The phenomenon of windup and its influence on the quality of control have been described. Selected methods of compensating this phenomenon are presented. A comparative analysis of algorithms was made in terms of their impact on the quality of control in the presence of changes in the feed flow rate. As a criterion, the relative value of the integral from the error square and the relative production value were presented, illustrating the impact of the considered algorithms on the economic effects of enrichment.

Identification of Carbon loss in the production of pilot-scale Carbon nanotube using gauze reactor

Carbon loss more than 65% was the major obstacles in the Carbon Nanotube (CNT) production using gauze pilot scale reactor. The results showed that the initial carbon loss calculation is 27.64%. The calculation of carbon loss, then, takes place with various corrections parameters of: product flow rate error measurement, feed flow rate changes, gas product composition by Gas Chromatography Flame Ionization Detector (GC FID), and the carbon particulate by glass fiber filters. Error of product flow rate due to the measurement with bubble soap gives calculation error of carbon loss for about ± 4.14%. Changes in the feed flow rate due to CNT growth in the reactor reduce carbon loss by 4.97%. The detection of secondary hydrocarbon with GC FID during CNT production process reduces carbon loss by 5.14%. Particulates carried by product stream are very few and merely correct the carbon loss about 0.05%. Taking all the factors into account, the amount of carbon loss within this study is (17.21 ± 4.14)%. Assuming that 4.14% of carbon loss is due to the error measurement of product flow rate, the amount of carbon loss is 13.07%. It means that more than 57% of carbon loss within this study is identified.

Simulation-Based Artificial Neural Network Predictive Control of BTX Dividing Wall Column

For the separation of ternary liquid mixture, use of dividing wall column is one of the nonconventional techniques in the field of liquid separation by thermal process. Benzene, toluene, and o-xylene have been selected as a ternary system for this study. As it is difficult to control the product purity directly due to delay time in the composition analyzer, temperatures of the appropriate trays were selected as the controlled variables. Reflux rate, sidestream flow rate, and reboiler heat duty were selected as manipulated variables to control sixth tray temperature of rectifying section, 11th tray temperature of the main column, and 12th tray of stripping section. Back-propagation algorithm was used as a training algorithm to tune the connection weights for the function of each neuron. The control performance of ANNPC was investigated for ±10 % load changes in feed flow rate, feed composition, and liquid split factor. The control performance was analyzed by using performance criteria indexes and performance parameters such as IAE, ITAE, ISE, ITSE, rise time, and settling time. It is observed that these performance parameters are less for ANNPC as compared to PID control. The settling time in case of PID varies from 2.77 to 4.55 h, significantly higher than that in ANNPC (0.37–0.66 h). The rise time is 0.66–1.20 h for PID and 0.03–0.27 h for ANNPC. These results indicate that ANNPC performs better than PID controller.

Study of gas holdup and pressure characteristics in a column flotation cell using coal

Present work has been carried out to observe the effect of process variables (gas flow rate, feed flow rate, solid concentration and frother concentration) on gas holdup and pressure characteristics in flotation column using coal. Gas holdup has been estimated using phase separation method while piezometers have been used to obtain column’s axial pressure profile. It was observed that gas holdup in collection zone was affected by both air as well as feed flow rates. Up to 6% change in gas holdup may occur when the feed flow rate changes from 1–2 cm/s. It was also observed that addition of coal decreased the gas holdup while addition of methyl isobutyl carbinol (MIBC) had opposite effect. Almost linear variation in columns axial pressure characteristics has been observed with gas flow rate. An empirical relationship between gas holdup in the flotation column with column’s axial pressure difference was developed.

Flow of Granular Material through Rotating Cylinders: Modelling Transients

ABSTRACTGranular material, fed continuously into the top of a slowly rotating, slightly inclined cylinder, forms a moving bed. Much of the bed rotates with the cylinder in solid body motion. When particles reach the surface of the bed, they move rapidly down it, and are absorbed once more into the solid body motion. Such cylinders are used in calcining, pharmaceutical manufacture, and drying. A steady state transport model, applicable when the bed depth varies slowly along the cylinder, has existed for around 50 years. The bed surface is considered locally flat, and particles in it fall along the line of steepest descent, inclined to the horizontal at the angle of repose. There is reasonable agreement with experiment.We propose a quasi-steady state dynamical model, in which the steady state model is coupled with a volume balance across an axial element. The model takes the form of a nonlinear diffusion equation which was solved numerically. The parameters of the dynamic model are the dimensions of the cylinder and outlet dam, the inclination of the axis of the cylinder, its rotational speed, the angle of repose of the granular material and its feed volumetric flow rate: the dynamic model has no free parameters. Experiments were conducted using sand, mean particle size 490 μm, in a perspex tube of length 1 m, radius 0.0515 m, lined with sandpaper, with a feed end dam of height 0.029 m, and with no exit dam, or an exit dam of height 0.0105 m. With the system initially in steady state, step changes in feed flow rate, rotational speed or axis inclination were imposed, and the resulting discharge flow rate and bed depth axial profile measured as functions of time. Good agreement is found between model and experiment.

Multivariable and multirate self-tuning control: a distillation column case study

This paper is concerned with the evaluation of self-tuning control algorithms for the multivariable control of distillation columns. Effective distillation control remains a key concern of industry because of the high energy consumption associated with distillation processes. The results presented here are taken from a continuing programme of investigations aimed at improving distillation column control performance. The performance of several multi-variable self-tuning strategies is evaluated by online application to a pilot-scale binary distillation column which is subjected to disturbances of ±25% step changes in feed flow rate. The performance of the multivariable algorithms is compared with that achieved using conventional digital multiloop PI/PID control. The results have demonstrated that use of multivariable self-tuning control, in particular multirate-multivariable self-tuning control, can provide better regulatory performance for feed flow rate disturbances than can be achieved using a multiloop PI/PID strategy.

The Dynamics and Control of a Depropanizer

Abstract The dynamic and control behavior of a depropanizer that consists of 29 ideal trays plus condenser and reboiler, with feed introduced at the 12th tray, has been studied by digital simulation. Open loop dynamic behavior of the column was studied for step changes of up to 30% in the feed and reflux flow rates and heat input to the reboiler. For changes in feed flow rate, the disturbance variable used for the control studies, the column exhibited inverse behavior in the composition response of the light key component (propane) in the distillate and the heavy key component (isobutane) in the bottom product. However, no inverse response was observed for the controlled variables of the concentration of the heavy key in the distillate and the light key in the bottoms. Control behavior of the five component depropanizer column for conventional single product composition control as well as dual quality control was investigated using the DYCONDIST simulator. Results obtained using indirect control strategies by measuring tray liquid temperature(s) and direct control of the distillate and bottoms are presented. Performance of the dual quality control schemes is discussed with respect to predicted behavior based on static information from relative gain array and relative disturbance gain calculations.