Optimization in Process Design and Sizing of Chemical Engineering Equipments

Chemical engineering has invariably been one of the most sought-after fields. The industries, education, and research sectors require large quantities of chemical equipment. This led to the insistence of inventing an optimization process to design and size chemical engineering equipment.

Process Optimization aims to maximize the potential economics of a chemical process by making efficient changes in design while staying within the established constraints.

The apparent benefits of process Optimization are achieving better profit rates, increased processing rates, and reduced energy consumption. Such optimization is to be performed for designing as well sizing of equipment.

Chemical Equipments

Chemical engineers generally work in chemical, petrochemical, oil & gas, food, pharmaceutical, and biotech. Before we discuss the optimization process of chemical engineering equipment, let’s take a brief look at the equipment that is useful in the industries mentioned above.

Chemical Engineering Equipment list:

1. Adiabatic Batch Reactor is a closed component with an input and output stream. This equipment has to be operated under adiabatic conditions. Because the use of this product is to study homogeneous catalytic reactions under adiabatic conditions, it comprises a Dewar flask with a capacity of 1 liter and a stirrer fitted inside.
2. Combined Flow Reactor helps to study a non-catalytic homogeneous second order liquid phase reaction in a combined flow reactor, under a condition that the surrounding is ambient. The Reactor system is made of two reactors connected in series, out of which the first is a plug flow reactor and the second is a mixed flow reactor. Another is a hybrid flow reactor. In this equipment, the mixing is performed in the perpendicular direction of flow and not actually in the flow direction.
3. Continuous Stirred Tank Reactor is alternatively known as Compressed Air Feed System or CSTR. The liquids in the reactor have uniform texture and composition throughout and are mixed well. Hence, the fluid that exits out of the reactor has the same composition as that of the fluid present in the reactor. This reactor is utilized to study non-catalytic homogeneous second order liquid phase reactions while the conditions are ambient.
4. Trickle Bed Reactors are commonly used in chemical industries and several other related industries like gas and oil, coal, petrochemical, waste treatment, and biochemicals. A glass column is used to study hydrodynamics. The fluid is fed from a tank of stainless steel to prevent corrosion. Manometers are provided with the whole set-up, which is essential to conduct the experiments.
5. Isothermal Batch Reactor is another closed-system equipment, which means the absence of both inputs and output streams. The reactor is fitted in bath water which is at a constant temperature. The bathwater temperature is maintained by utilizing Digital Temperature indicator Cum Controller from ambient to 90ºC.

Now that we’re familiar with the equipment let’s study its optimization process.

Optimization Process

Optimization is an inherent part of the design. The designer seeks the best or optimum solution to a problem.

Following elements are required for the task of the Optimization process.

1. 1. An objective function: The objective function provides scalar quantitative performance measures. This is the measure which has to be either maximized or minimized to aid the Optimization process. This could be profit, yield, system cost, etc.
   2. A predictive model: The description of the behavior of the whole system must be done by the predictive model. In the context of the optimization process, this is converted into constraints. Constraints mean a set of inequalities and equations. Limits of system performance are defined by these constraints.
   3. Variables: The variables that the predictive model defines have to be adjusted to satisfy the constraints. This is achieved by considering multiple cases of variable values which lead to a feasible region. This region is decided by the subspace of the variables. This subspace is distinguished by a set of decision variables. Upon interpretation, we would discover the degree of freedom allowed in the process.

Process Optimization Examples:

The optimization process is implemented in many ways to design and to the size of chemical equipment and plants.

• Design of a heat exchanger network,
• Scheduling maintenance and equipment replacement
• Operations planning and scheduling, Equipment sizing
• Operating equipment, such as reactors and columns.
• Real-time optimization of a distillation column

Process Optimization of Chemical Equipment Sizing

For the sizing optimization process, a method involving vessels’ minimum mass and minimum surface area conditions has been considered.

The dependences of the optimal mass, diameter, height, and

minimum surface area of the hull on the volume of the vessel are achieved. The Optimization process is performed on dimensions which leads to substantial structural materials being saved and the cost of vessels being reduced.

Conclusion

The demand for chemical engineering equipment is pretty high among industrial, educational, and research sectors, which makes the Optimization process of designing and sizing equipment inescapable. The equipment on which process optimization has been successfully performed are- reactors columns, heat exchange network, etc., to name a few.

The elements necessary to perform this task are an objective function, predictive model, and variables that can be adjusted to achieve efficiency and satisfy constraints at the same time.

To optimize the sizing of chemical equipment, dimensions are altered, which leads to a reduction in the cost of vessels, and structural material is saved.