How to improve your processing plant without large investments?

How to improve your processing plant without large investments?

Any processing plant – continuous, batch, hybrid – can improve its economic, safety and environmental indicators in two ways: improving its processing equipment or improving the control of those equipments.

The improvement of processing equipment is usually a task that requires large investments, since it almost always involves the acquisition of new processing equipment or in the best case requires expensive remodeling.

On the contrary, these performance indicators can be substantially improved through control, without, in the majority of cases, any investment in new technical means of instrumentation and control. This is because in practically all cases there is a wide margin to improve the performance indicators of a processing plant through its regulation.

The origin of this margin of improvement is multiple. The most common causes are: the control system is not well designed or tuned; due to ignorance or haste, all the benefits of the available control system are not used; the automaton programmer or the process engineer are not control experts; the dynamics of the processes under automatic regulation are not known with the required depth; the design of the plant has not been made under the integrated design approach.

Are also diverse and numerous actions that can be implemented to improve the performance of control loops without any investment and that we will review in next posts, such as: improve the tuning of the regulator, redesign the controller, implement anticipatory compensation of disturbances, enhance the tuning of cascade regulation loops, redesigning or re tuning the level controllers of the buffer tanks if necessary, using a control algorithm advanced available or supportable by the controller instrument, reducing couplings between loops, making a better assembly of the measuring probe, etc.

In its vast majority, the processing plants are automated under control structures (basic control, cascade control, split range control, selective control, coupled loops, etc.) based on the universal PID controller, in all its particularizations (P, PI, PD, PID, PI_D, etc.).

Despite its longevity and the development of multiple advanced control techniques, PID control maintains an overwhelming presence in the process industry.

Its extensive use in the industry is such that all the surveys known by the author conclude unanimously, in which more than 95% of the existing control loops are of the PID type. However, also many surveys conclude that a high percentage of the loops with PID control in the world, are operated in manual mode, while another similar percentage operates defectively. For example, as shown in the following figure, in [1] it is reported that only 16% of the PID regulation loops are optimally tuned and their performance is therefore excellent.

There is no doubt that in most cases, the incorrect or poor tuning of the controller can be the cause of the poor performance of the control loop or its irregularities in the operation.

However, it should not be forgotten that automatic regulation systems are holistic systems, and as such they must be analyzed as a whole and not only through the parts that compose them. That is why it is necessary to review the other components of the loop before deciding what action should be exercised on said loop.

Hence, the procedure of action in all cases, must begin with a field review of all the components of the loop (controller, process, actuator, measurer and communication channels), as well as an analysis of the possibility of coupling with other process loops.

The result of this first phase will determine what concrete action corresponds to perform to solve the poor performance of the automatic regulation loop.

CARTIF offers this service to optimize the performance of the regulation systems of processing plants. The optimization reduces the oscillations and the variability of the production plant, making the regulation system more accurate, faster, more stable and safer, and in this way improving its efficiency, safety, environmental impact and profitability.

In next post, the execution procedure will be described for each of the possible actions, starting with the simplest one, the re-tuning of the controller.

Fighting with triple A (AAA), the silent enemy

Fighting with triple A (AAA), the silent enemy

The Abdominal Aorta Aneurysm (AAA) has been recognized as a major health problem in the last decade. The statistics associated with this condition are of great concern and, as recorded in most of the studies found in scientific literature, it is expected that its impact will increase in the next years mainly due to the increase in life expectancy of the population. The rupture of abdominal aortic aneurysms represents a major clinical event because of its high mortality rate.

According to Dr. Felix Nieto comments in his previous post, currently the indicators used to determine the treatment of patients with aneurysms are the maximum transverse diameter and the growth rate that can be considered insufficient; they do not have a physically grounded theoretical basis. Because of this limitation, in recent years research has been basically aimed at improving understanding of the phenomena associated with the emergence and evolution of this disease, in order to determine whether other variables could be predictive of rupture.

One of the major constraints in obtaining accurate results in modeling vascular diseases is the use of a realistic computational domain, which is closer to be possible due to technological advances in equipment for conducting tomography computed axial (CT), magnetic resonance imaging (MRI) and the development of CAD techniques, which has advanced significantly in the detailed extraction, in vivo, of anatomical structures.

CARTIF team is working on automated conversion of 2D set of images obtained by CT in a realistic 3D model that constitutes the geometric domain of integration into the AAA simulation by finite element techniques

The activity related to medical imaging AAA has been the key to one of the issues recently treated in CARTIF, called the study of the influence of geometric parameters on the rate of rupture of AAA, the work is particularly focused on iliac angle.

In the first phase they were carried out fluid dynamics and structural simulations to calculate the Rupture Potential Index (IPR) of several cases of patients affected by AAA

The results show that the values of the iliac angle (α) are related to other geometric parameters such as the eccentricity of AAA, which together can characterize the IPR.

The next step would confirm this trend over a larger database of patients with AAA, being essential as now, the good cooperation with HCUV (University Clinical Hospital of Valladolid).

For the simplicity of obtaining these parameters by the specialist through the TAC, the results of this research could be a very effective tool for the surgeon when making the decision to submit or not the patient to a surgical repair procedure.