Aspen HYSYS reforming

The cahbration process for the FCC is square . This implies that there are no user adjustable tuning factors unlike the Aspen HYSYS Reformer or Hydrocracking models. In other words, the number of tuning parameters equals the number of available measurements and the calibration is a much simpler root-finding exercise. In general, the calibration process is quick and converges within 20 iterations. If there is difficulty during calibration, it is mostly likely due to inconsistent product measurements. 

The major units of the Aspen-HYSYS simulation for natural gas steam reforming based fuel cell system are presented in Figure 3. 

Aspen HYSYS Petroleum Refining Catalytic Reformer Model... 

Figure 5.9 shows a basic outline of the key submodels in Aspen HYSYS Petroleum Refining. This model contains aU the key submodels identified in the previous section. The model presented in this work includes the additional fractionation units to model the separation of LPG (< C4) and tire reformate into gasoline and high-octane compounds for blending and chemical purposes. 

Table 5.6 Key reactions classes in Aspen HYSYS Petroleum Refining Catalytic Reformer model. ...

In the following workshops, we demonstrate how to organize data, build and calibrate a model for a catalytic reformer using Aspen HYSYS Petroleum Refining. We discuss some key issues in model development and how to estimate missing data required by Aspen HYSYS Petroleum Refining. We divide this task into four workshops ... 

We start by opening Aspen HYSYS. The typical path to Aspen HYSYS is to enter the Start > Programs > AspenTech > Aspen Engineering Suite > Aspen HYSYS. Early versions may include a menu entry titled Aspen RefSYS. The correct program to start is Aspen HY SYS (Shown in Figure 5.39). We dismiss the Tip dialog and select File > New > Case. We wish to include fractionation, so we do not choose Reformer alone. 

It is important to note that even when we choose an equation-of-state approach. Aspen HYSYS does not calculate all physical properties from the equation of state. For hydrocarbons, equations of state do not generally predict the equilibrium properties of very light components such as hydrogen. In addition, density predictions (especially in the heavy hydrocarbon range) can be quite poor. We almost always modify the equation of state to account for these deficiencies. For the reforming, process we choose the COSTALD Method (Section 1.8.4) to predict the liquid density (Figure 5.44). 

The last step before building the reformer flowsheet is to verify the interaction parameters (Figure 5.45). If we had chosen a correlation-based approach (Grayson-Streed, etc.), we do not have to examine the interaction parameters. Since we choose an equation of state approach, we must make sure that the binary interaction parameters for the equation-of state are meaningful. In Aspen HYSYS, the interaction parameters for defined components (such as methane. 

The initial flowsheet presents a blank interface where we can place different objects from the Object palette shown in Figure 5.46. The initial tool palette only shows typical unit operations and does not show the advanced Aspen HYSYS Petroleum Refining objects. We will use both toolbars to build out the complete reformer model. We can bring the up the advanced palette by pressing F6. 

The first step is to choose whether to use a reformer template or configure a new unit Aspen HYSYS has several reformer templates that reflect several popular tjrpes ofindustrial reformer configurations. Figure 5.48 shows the initial window when place a Reformer object on the Flowsheet If we choose a template, we do not have to assign the reactor dimensions and catalyst loadings. However, in this workshop, we will build a reformer from scratch, so we choose Configure a New Reformer Unit . 

Figure 5.54 shows the Feed Data tab from the Reformer sub-model. The Feed Type is a basic set of relationships and initial values for the all kinetic lumps in the reactor model. Aspen HYSYS uses bulk property information such as density, distillation curves and total PNA content in conjunction with the feed type to predict the composition of feed lumps to the model. The Default type is sufficient for hght-to-heavy naphtha. However, there is no guarantee that a particular feed type represents the actual feed accurately. Aspen HYSYS will attempt to manipulate the feed composition to satisfy bulk property measures given. In general, we advise users to develop a few sets of compositional analysis to verify the kinetics lumps calculated by Aspen HYSYS. We discuss a process to verify these lumps later. 

We perform this rescaling by copying the results of the Feed Blend (Figure 5.70) from Aspen HYSYS into Column 1 of the spreadsheet. We also enter the measured compositional information in Column C. The results of the re-scaling appear in Column U. We must now enter the re-scaled feed information back into the reformer model. We must reenter the Reformer sub model and enter the Feed Data Tab. 

The first step is to Pull data from the simulation. When Aspen HYSYS pulls data, current operating conditions, feed stock information and process parameters enter the reforming environment. A Calibration refers to the set of the activity factors that produce a given product yield and reactor performance (which we provide to the calibration environment) based on the current model state. We pull data by click on the Pull Data from Simulation button (Figure 5.78). 

When we pull data from the simulation. Aspen H YSYS will warn us that current calibration data will be overwritten by the current model results as shown in Figure 5.79. We can use the Data-Set feature (in Figure 5.80) to allow multiple calibration data-sets. This may be useful if the industrial reformer runs under very different operating scenarios. However, for the purposes of this workshop, we will use only one calibration data set Aspen HYSYS will pull all the feedstock information and process operating after we confirm the calibration data overwrite. The status bar now indicates that we must specify product measurements to begin the calibration process. 

Next we specify the flow rates, yields and composition of all the key streams from the reformer. A compositional analysis is necessary to make sure that we model key reaction paths accurately. We recommend that users enter all compositional information for gas streams in mol% and aU compositional information for liquid streams in vol.% or wt.%. Given the data available, we can enter the flow rates of each steam on a gas flow or mass flow basis. We note that internally. Aspen HYSYS will convert all measurements into a mol% to ensure overall material balance in the model results. 

We save the model calibration by clicking Save for Simulation... in the Analysis tab of the Refomer Calibration Environment. Aspen HYSYS will prompt us (see Figure 5.91) to save this calibration as Set-T. We can have multiple calibrations for the same reformer and use different calibrations sets for different operating scenarios. We recommend only having only calibration set per reformer model file. 

After saving the Calibration, we shordd put the solver in holding mode to make sure that Aspen HYSYS exported the calibration factors properly. We will return the Reformer Sub Flowsheet environment We recommend that users go through each one of the tabs in Reformer Sub Flowsheet environment to make sure that the input data has not changed. It is also important to make sure that the basis for the kinetic lumps is same as what was chosen initially (In this work, we always use wt.%, see Figure 5.93). We can release the solver to allow Aspen HYSYS to solve the model as shown in Figure 5.92. 

Abstract In this paper, we discuss the results of a preliminary systematic process simulation study the effect of operating parameters on the product distribution and conversion efficiency of hydrocarbon fuels in a reforming reactor. The ASPEN One HYSYS-2004 simulation software has been utilized for the simulations and calculations of the fuel-processing reactions. It is desired to produce hydrogen rich reformed gas with as low as possible carbon monoxide (CO) formation, which requires different combinations of reformer, steam to carbon and oxygen to carbon ratios. Fuel properties only slightly affect the general trends. 

Fuel cell system models have been developed to help understand the interactions between various unit operations within a fuel cell system. Most fuel cell system models are based on thermodynamic process flow simulators used by the process industry (power industry, petroleum industry, or chemical industry) such as Aspen Plus, HYSIS, and ChemCAD. Most of these codes are commercially distributed, and over the past years they have offered specific unit operations to assist modeling fuel cell stacks (or at least a guide for putting together existing unit operations to represent a fuel cell stack) and reformers. Others (16) have developed more sophisticated 2-D... 

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