Modern Process Plants Research Articles

Automatic Model Generation for Virtual Commissioning based on Plant Engineering Data

The complexity of modern process plants is steadily increasing – and thus the demands placed on automation systems. Today, the validation and testing of an automation system is a demanding task, usually executed under very tight schedules. Therefore, the use of simulations to check-out the automation system earlier in the engineering phase can be very beneficial. This paper investigates the possibility of automatically generating simulation models based on plant engineering data, usable for virtual commissioning. The proposed mechanism is usable without any specific additional application and can be realized with the plant engineering and simulation tool alone. The concept and workflow will be described in detail, and the paper concludes with a case study based on a prototypical implementation. Based on the proposed concept, the reuse of engineering data to generate simulation models, and thus the broader use of simulation throughout the lifecycle, becomes easier and therefore more feasible.

Networks in Argentine agriculture: a multiple-case study approach

Argentina is among the four largest producers of soybeans, sunflower, corn, and wheat, among other products. Institutional and policy changes during the 1990s fostered the development of Argentine agriculture and the introduction of innovative process and product technologies (no-till, agrochemicals, GMO, GPS) and new investments in modern, large-scale sunflower and soybean processing plants. In addition to technological changes, a quiet revolution occurred in the way production was carried out and organized: from self-production or ownership agriculture to a contract-based agriculture. The objective of this paper is to explore and describe the emergence of networks in the Argentine crop production sector. The paper presents and describes four cases that currently represent about 50% of total grain and oilseed production in Argentina: informal hybrid form, agricultural trust fund, corporate structure, and network of networks. In all cases, hybrid forms involve a group of actors linked by common objectives, mainly to gain scale, share resources, and improve the profitability of the business. Informal contracts seem to be the most common way of organizing the agriculture process, but using short-term contracts and sequential interfirm collaboration. Networks of networks involve long-term relationships and social development, and reciprocal interfirm collaboration. Agricultural trust fund and investor-oriented corporate structures have combined interfirm collaboration and medium-term relationships. These organizational forms are highly flexible and show a great capacity to adapt to challenges; they are competitive because they enjoy aligned incentives, flexibility, and adaptability.

Robust optimization-based multi-loop PID controller tuning: A new tool and its industrial application

Modern process plants are highly integrated and as a result, decentralized PID control loops are often strongly interactive. The iterative SISO tuning approach currently used in industry is not only time consuming, but does also not achieve optimal performance of the inherently multivariable control system. This paper describes a method and a software tool that allows control engineers/technicians to calculate optimal PID controller settings for multi-loop process systems. It requires the identification of a full dynamic model of the multivariable system, and uses constrained nonlinear optimization techniques to find the controller parameters. The solution is tailored to the specific control system and PID algorithm to be used. The methodology has been successfully applied in many industrial advanced control projects. The tuning results that have been achieved for interacting PID control loops in the stabilizing section of an industrial Gasoline Treatment Unit as well as a Diesel Desulfurization plant are presented.

Comparison of Campylobacter Contamination Levels on Chicken Carcasses between Modern and Traditional Types of Slaughtering Facilities in Malaysia

A total of 360 samples including fresh fecal droppings, neck skins, and swab samples was collected from 24 broiler flocks and processed by 12 modern processing plants in 6 states in Malaysia. Ninety samples from 10 traditional wet markets located in the same states as modern processing plants were also collected. Microbiological isolation for Campylobacter was performed following ISO 10272-1:2006 (E). The overall rate of contamination for Campylobacter in modern processing plants and in traditional wet markets was 61.1% (220/360) and 85.6% (77/90), respectively. Campylobacter jejuni was detected as the majority with approximately 70% for both facilities. In the modern processing plants, the contamination rate for Campylobacter gradually declined from 80.6% before the inside-outside washing to 62.5% after inside-outside washing and to 38.9% after the post chilling step. The contamination rate for Campylobacter from processed chicken neck skin in traditional wet markets (93.3%) was significantly (P<0.01) higher than in modern processing plants (38.9%).

Description of failure modes in welded components operating in the creep regime

Welding is one of the most important joining technologies in modern process and power plant construction. At present, martensitic heat resistant 9–12% chromium steels are one of the favored materials used for high temperature components, because of their good weldability, excellent hot workability and high creep strength. Nevertheless, under service conditions, for a number of these martensitic steels, the fine grained or intercritical heat affected zone (HAZ3) has the poorest creep strength since the heat input of the welding affects the microstructure of this zone. Furthermore the stress situation and multiaxiality of the stress state in the weld region changes permanently due to creep and relaxation. Experimental results show a strong influence of the factor of multiaxiality of the stress state on the creep behaviour of components especially of welded components. This paper gives a phenomenological description of the specific damage and failure behaviour of creep loaded welds. The previously mentioned time dependent stress — strain situation in weldments will be discussed and the influence of the multiaxiality of the stress state will be identified. Basic possibilities to avoid premature failure in the HAZ region are shown such as the optimum heat treatment of the base metal (BM) prior to welding, the variation of the welding methods and the optimization of the welding geometry and the deposit materials.

Graphical Representation of Industrial Alarm Data

Alarms are important for safe and reliable operation of a process. Ideally, every alarm that is presented to the operator requires an action. Owing to the ease in implementing alarms, many modern day process plants have a large number of alarms configured in their alarm system. Many of these alarms are set without proper rationalization resulting in the generation of nuisance alarms. During process upsets, the volume of alarms presented to the operator is often too large to facilitate appropriate and timely actions. This work demonstrates some novel visualization tools that can be used for assessing the performance of alarm systems in terms of effectively identifying nuisance alarms. The utility of the developed tools is illustrated using real industrial alarm data.

Focus on mission success: Process safety for the Atychiphobist

Modern process plants are complex engineering systems. While thorough reviews of system safeguards are performed, catastrophic events continue to occur, often unfolding in unforeseen ways. Success in process safety demands safe processes, and understanding rare, high consequence events is central to the traditional process safety approach. This philosophy is common to all high-hazard industries, offering the potential for sharing approaches, experience, and lessons learned. The problem, however, is that people (and organizations and entire industries) who fear failure (atychiphobia) sometimes obsess about failure so much that they miss opportunities to succeed. This paper examines selected risk management practices in the power generation and aerospace industries and how those practices have led to improved performance. Risk informed decision making (RIDM) has had widespread application in the nuclear and aerospace industries, and is undergoing enhancements to become a key framework for risk management. Additionally, rather than focusing on avoidance of loss, there are emerging approaches supporting achievement of success. This approach provides a more direct link of risk to business and operational objectives, but does challenge conventional risk approaches founded in a loss prevention-centric view. The paper reflects upon risk informed decision making and success modeling, and suggests how these methods may be applied in the field of process safety. Specific examples are drawn from the defense in depth approach from the nuclear power industry and mission success concepts developed for NASA.

Robust optimization-based multi-loop PID controller tuning: A new tool and an industrial example

Modern process plants are highly integrated and as a result, decentralized PID control loops are often strongly interactive. The currently used sequential tuning approach is not only time consuming, but does also not achieve optimal performance of the inherently multivariable control system. This paper describes a method and a software tool which allows a control engineer to calculate optimal PID controller settings for multiloop systems. It is based on the identification of a state space model of the multivariable system, and it uses constrained nonlinear optimization techniques to find the controller parameters. The solution is tailored to the specific control system and PID algorithm to be used. The methodology has been successfully applied in several industrial advanced control projects. The tuning results which have been achieved for interacting PID control loops in the stabilizing section of an industrial Gasoline Treatment Unit at SABIC Petrochemicals are presented.

Neural network classifiers applied to condition monitoring of a pneumatic process valve actuator

As modern process plants become more complex, the ability to detect and identify the faulty operation of pneumatic control valves is becoming increasingly important. In this work, a neural network pattern classifier is employed to carry out fault diagnosis and identification upon the actuator of a Fisher–Rosemount 667 industrial process valve. The network is trained with experimental data obtained directly from a software package that comes with the valve. This has eliminated the need for additional instrumentation of the valve. Using this software, tests are carried out to obtain experimental parameters associated with the valve performance for incorrect supply pressure, diaphragm leakage, and vent blockage faults. Specifically, the valve signature and dynamic error band tests are used to directly obtain lower and upper bench sets, minimum, maximum, and average dynamic errors, as well as the dynamic linearity. Additionally, valve deadband and hysteresis are measured graphically from the available valve signature plots for each faulty condition. The relationships between these parameters, for each fault, form signatures that are subsequently learned by a multilayer feedforward network trained by error back-propagation. The test results show that the resulting network has the ability to detect and identify various magnitudes of each fault. It is also observed that a smaller network with a shorter training time results when the valve deadband and hysteresis are included in the training data. Thus, the extra effort required to extract these parameters from the valve signature plots is justified.

Constant level lubricators and other bearing protection devices: how smart retrofits will improve equipment reliability

To this day, some important lubricant application and bearing protection issues are still being overlooked or misunderstood in the typical modern process plant environment. Satisfactory explanations are not forthcoming, leading the industry to loose faith in equipment reliability. Heinz P Block sees if he can find a solution.

Measurement validation via expected uncertainty

Validated sensor data is critical to the operation of a modern process plant as erroneous data can degrade process performance. Consequently measurement validation is a necessary part of process management. Self-validating sensors reference observed sensor performance against a local model of ideal sensor behaviour. Discrepancies between the observed and desired sensor response are used to resolve faulty sensor operation and indicate the resultant measurement quality. However, non-ideal aspects of the validation problem lack treatment in many existing self-validation methods and require the validated-measurement model to have a probabilistic foundation. This paper prescribes a formal basis for integrating non-ideal diagnostic information into a stochastic model of sensor operation. The analysis is presented in the context of an existing self-validation framework with a mass-flow simulation illustrating the concept.

Operation of modern day process plants – minimising Cryptosporidium risk

Closer examination of basic water treatment processes, “source to tap”, is one of the evident supplier responses to new quality constraints and increasing resource pressures. More recently, with the release of DWI Incident Reports and UKWIR documentation on the organism Cryptosporidium, the focus has been extended to defining and operating at “optimal” conditions within treatment processes. As a result the Water Industry is currently re-evaluating “due diligence” guidance of operational procedural practices on treatment streams, in order to consistently produce potable water to an ever increasing standard, and thus lowering the public health risk.

The role of gravity concentration in modern processing plants

Next to hand picking, gravity concentration is the oldest of all forms of mineral processing. While, in the twentieth century gravity concentration has been partially replaced by other processes, notably flotation and magnetic separation, they have not made it obsolete. That such an ancient and inherently simple process has not only survived, but thrived, is in part due to its very simplicity. Not only is gravity concentration the process of choice in small, remote, artisanal plants, it also continues to play a major role in larger, “modern” plants for the concentration of many minerals, literally from A (andelusite) to Z (zircon). This paper will review some of the advances in gravity concentration equipment and technology, that has allowed it to keep pace with, and grow, in what is becoming an increasingly competitive world. Various examples of modern equipment, and their potential application will be given. The paper will serve to challenge the mineral processing engineer to ask himself: “can gravity concentration solve my problem too?”

Numbers and Species of Motile Aeromonads during the Manufacture of Naturally Contaminated Spanish Fermented Sausages (Longaniza and Chorizo)

The prevalence of aeromonads in the initial mixes of 14 batches of chorizo and longaniza obtained from three small- and middle-sized factories was 78.5%, with counts ranging from >1.00 to 4.47 log10 CFU/g. Only 2 of 10 mixture samples prepared at a large and modern processing plant yielded these organisms, with levels below 1 log10 CFU/g. The hygienic status of factories significantly affected incidence and counts. Of 39 presumptive isolates from glutamate starch penicillin agar, 36 were confirmed as motile aeromonads and allocated to Aeromonas hydrophila (n = 24), A. veronii biovar sobria (n = 10), and A. caviae (n = 2). All of them were beta-hemolytic and capable of growing at 5°C. Regardless of initial contamination, aeromonads were rapidly inactivated during the early stages of manufacture.

Overall site optimisation by Pinch Technology

The importance of integration in process plant design has long been recognised. This is evidenced for example, by the existence of complex heat and power networks in modern production sites. These networks represent site-wide integration. They usually allow process heating duties in several processes to be effected at low cost by using turbine pass-out steam after obtaining a credit for power generated in a central turbine. When looking for energy saving in retrofit projects, an installed heat and power network of this type usually introduces a counter-productive element. A reduction in steam heating duties leads to a reduction in turbine pass-out steam which, in turn, leads to a reduction in power generation. This makes optimisation of the process alone and optimisation of the process in the site context two rather different tasks. More complications are given through other more general reflections across a site. A modern processing plant such as ethylene, for instance, is usually linked into the overall site and interacts with other plants through several utilities, not just back pressure steam. This makes it necessary to not only understand the fundamental process demands but also to analyse these demands in the site context. Process licensors will usually prefer to consider standard designs for individual processes. The best project, on the other hand, will almost invariably be site dependent. This article highlights the distinction between the application of process integration techniques—in particular pinch technology—within an individual process and their wider application in the overall site context. The “counter productive” aspect of heat savings in the context of isntalled heat and power networks is given attention. In addition to energy, the article discusses yields, flexibility and capital cost savings.

Microbiological Quality of Broilers During Processing in a Modern Commercial Slaughterhouse in Kuwait

The effect of processing procedures and overall environmental and hygienic conditions on the microbiological quality and safety of chicken carcasses was studied in a modern processing plant on two separate days. The level of microorganisms on chicken carcasses was assessed by a neck-skin “maceration” method. Carcasses were heavily contaminated by different types of organisms, including indicator organisms (total aerobics, Enterobacteriaceae, coliforms and Escherichia coli) and pathogens (e.g., Salmonella, Campylobacter and Staphylococcus aureus). Microbial levels varied during processing, but the highest levels were detected after scalding and defeathering. Microbial levels did not change during vent opening or evisceration.Spray washing after evisceration did not reduce levels of bacteria. No substantial change occurred in bacteria levels during air-chilling, packaging and cold-storage; however, the finished product was heavily contaminated. In the freshly processed carcasses, mean counts (log colony forming units [CFU]/g neck-skin) of aerobic bacteria Enterobacteriaceae, coliforms, E. coli, Campylobacter and S. aureus were 6.6, 4.5, 4.1, 3.6, 5.2 and 2.7 on the first sampling day, and 6.5, 4.6, 4.9, 3.6,4.7 and 4.1 on the second day. Salmonella was present in all birds examined, including those coming directly from the farm. Major serotypes detected on dressed carcasses were Salmonella ohio, Salmonella enteritidis, Salmonella paratyphi and Salmonella krefeld.

Environmental Issues for the Poultry Industry: Processing

The water flow and waste loading patterns of a modern broiler processing plant (260,000 birds per day) were studied. The study was conducted in two phases. The first phase examined the water flow and waste-loading patterns during a 24-h period. The second phase studied flow and waste-loading patterns from five major process functions of the plant. The first phase study showed that 84% of the water flow of the plant was used for processing and the remaining 16% for plant sanitation. Based on received water, this plant used 5.08 gal (1 gal = .379 L) per bird. Analysis of the waste stream from five process functions determined that 72% of the plant flow came from the evisceration operation. The feather flow operation and the offal truck contributed 83% of the NH3 N discharged by the plant. Definition of flow and waste-loading patterns provides valuable information for enhancing water conservation and waste minimization.

Basics and industrial applications of pressure swing adsorption (PSA), the modern way to separate gas

Pressure swing adsorption (PSA) technology is increasingly applied for purification of gases and for bulk separation of most various gas mixtures. Typical product gases are hydrogen, carbon monoxide, ethylene, nitrogen, oxygen and methane. This paper presents an introduction to the technique of PSA plants and gives a survey of current practical applications of adsorption technology in modern process plant complexes.

Distributed Control System for a Modern Process Plant

This paper describes microprocessor-based distributed control system for a typical process plant—a modern chemical plant. The microprocessor based controls execute the tasks best suited to their capabilities, but several loops have analogue controls which are integrated into the system to provide control where the sampling interval would be detrimental. Control loops fully utilize the logic and calculation capabilities of the microprocessor controls.

Transducers, instruments and measurements in the process industries

The monitoring and control needs of modern process plants have stimulated the development of new types of measurement devices and systems to support them. This article describes modern trends in plant monitoring and control, and particularly the move towards optical devices