The lack of calcium and magnesium in drinking water affects people's health, especially cardiovascular and oncologic diseases, and causes corrosion problems. The aim of this paper is to present the methodology of the design, scale-up, and construction of a fluidized bed reactor (FBR) system for drinking water recarbonization with biogenic elements in real conditions. Half-calcined dolomite (HCD) in combination with CO2 was identified as a suitable source of Mg2+ and Ca2+. The experimental results confirmed that an FBR reactor with a water tank is an efficient system for Mg and Ca2+ ion concentrate production. The main process parameters and dimensions of the equipment were determined based on the experimental data and the data obtained showed that the system can be used in real conditions to produce Mg2+ and Ca2+ ions concentrate, which is mixed with soft water in required proportions. The FBR with an internal diameter of 0.16 m and a total height of 3.7 m was designed. The proposed methodology of the recarbonization process design was used in a further system scale-up for a ten times larger capacity. Long-term experiments indicate that the HCD recarbonization process is robust and can return to the steady state even after significant changes in the process parameters for providing the desired concentration of Mg2+ and Ca2+ ions in drinking water.

In recent years, process intensification and integration have played a key role in the world’s production of esters. This is successfully achieved by the reactive distillation process. In this work, intensification of the ethyl acetate production process is studied comparing three case studies: conventional process set-up (ethyl acetate is produced in a chemical reactor) is designed as a base case study; reactive distillation with a separation unit is derived from the conventional process set-up, and intensified of the latter pathway by the integration of a heat pump. Effect of the intensification was evaluated by multilevel assessment based on energy requirements, economic, environmental, and safety analyses. Safety evaluation was based on the Chemical Process Quantitative Risk Analysis performing individual risk estimation for all case studies.

Typical factors considered in industrial practice for process designs are material and energy efficiency, process economics and level of environmental burden caused by the new technology. In our work, we propose addition of process safety analysis into the decision-making. To overcome lack of process data known at early design stage, we have utilized safety index methods that are suitable to evaluate process safety level with minimum process knowledge required. Safety indices incorporated into the developed multiple-criteria decision analysis (MCDA) were Process Route Index and Comprehensive Inherent Safety Index. Material and energy efficiency was assessed through E factor and Specific Energy Consumption. Total Capital Cost and Total Production Cost were utilized to assess process economy. Finally, environmental impact was evaluated by C factor and Eco Indicator 99. The proposed MCDA methodology was tested on a case study of hydrogen production from natural gas and biogas. In total, sixteen different process design alternatives were generated and simulated in Aspen Plus. Utilizing Analytical Hierarchy Procedure (AHP) method, different weights were assigned to every calculated criterion to perform MCDA. After assignment of weights, final evaluation matrix for every process design alternative was generated. For easier interpretation of results, viability maps were constructed. Viability map is a 3D figure combining generated case studies, their score in individual criteria and importance of individual criteria represented by its weight. It was found out that natural gas as a feedstock was preferable if considering material and energy efficiency, process economics or process safety as the most important criterion. However, if environmental impact had the highest importance, biogas-based options were the highest rated options. Process safety factor was decisive in specific combination of other criteria. Hydrogen production from natural gas coupled with carbon capture technology for flue gas was identified as the overall best process route.

Safety is a key part of any modern production process and as such is reflected in legislation and work regulations. Decision-making concept based on inherently safer design principles is introduced in this paper. Two case studies representing typical modern chemical processes are studied with the emphasis on their inherent safety level. First case study is a novel process to convert refinery waste into valuable products – production of ammonium thiosulphate. As a second case study, production of ethyl acetate by esterification was selected due to its potential for process intensification through reactive distillation. For each case study, two design alternatives are proposed. Utilising process data, the design alternatives are evaluated using five safety indices and compared to each other to identify the inherently safer one considering fire and explosion hazards as well as toxicity level. Results show that different sensitivity of index methods can lead to different outcomes of hazard potential identification. For the second case study, results of each method were in agreement. However, reverse order of design alternatives was obtained in the analysis of the first case study. As a part of this article, novel processing technique employing geometry of polygons to assess hazard distribution and inherent safety level of different process routes has been introduced and employed. Obtained results suggest possible implementation of the proposed approach to robust multi-criteria decision analysis as a safety assessment criterion.

Carbon dioxide emissions associated with hydrogen production are expected to rise with continuous transition to hydrogen economy. The steam methane reforming as the most frequently used technology was heavily investigated in this work for options to reduce its carbon footprint. Three possible carbon capture (CC) approaches for steam reforming of natural gas are studied from techno-economic, safety and environmental point of view. The considered CC techniques are post-combustion CC of flue gases, pre-combustion CC of offgases from pressure swing adsorption (PSA) and oxyfuel combustion. For each investigated CC technology, mathematical model and process simulation were developed in Aspen Plus. Simulation data supplemented by safety data sheet data were used to assess all simulated case studies by multiple criteria - economic feasibility, use of resources, environmental impact, and inherent safety. Oxyfuel combustion was identified as the best option considering all criteria simultaneously.

Process safety and risk assessment are major requirements in the industrial context and hazard identification is essential for ensuring safe design and operation of a process. Numerous automated software approaches to risk assessment have resulted in many improvements in human brainstorming techniques of conventional risk assessment. In terms of computing time as an important aspect of these automated tools, mathematical simulation of physical and chemical states of the process is most time consuming in comparison to results collection and evaluation. In this context, GPU parallel computing has many advantages which meet the demanding requirements on complex and precise process hazard analysis without the involvement of massive processing architectures. This paper presents an efficient low-cost way of significant acceleration of targeted prediction of incident consequences by dynamic simulation of process fault deviations in the context of safety analysis. The GPU based simulation computing algorithm acceleration has been demonstrated on a hazard and operability analysis of propylene glycol production carried out in a closed loop CSTR (continuous stirred tank reactor). In this application, HAZOP multi-parameter process deviations have been simulated 100 times faster than when using its CPU code version. (C) 2020 Elsevier Ltd. All rights reserved.

In the process of real biomass supercritical water gasification (SCWG), process parameters such as temperature, pressure and space time have significant influence on the product composition together with the properties of feedstock being thermally decomposed. To exactly understand this process and for further design of reaction systems, it is necessary to develop an integral kinetic model including the kinetic equation for feed consumption, gas product production and the ability to describe the formation and consumption of intermediates causing technological problems. The entire process of real biomass gasification is quite complicated in terms of reactions pathways; however, the rate determining step is often the gasification reaction of simple organic compounds such as alcohols and carboxylic acids. In our work, experiments were done and kinetic models of methanol, ethanol and isopropanol gasification in supercritical water were determined. The feed concentration ranged between 5 and 45 wt% for methanol, 5–30 wt% for ethanol, 5–10 wt% for isopropanol. The temperature ranged from 620 to 820 °C. The pyrolysis reaction and the water gas shift reaction showed the main influence on product composition, while the effect of steam reforming reactions can be neglected in case of ethanol and isopropanol.

Process safety is of major importance in chemical industry. Numerous activities have targeted the modification of conventional risk assessment strategies by computer aided approach. In this paper, a software tool for Hazard and Operability (HAZOP) study based on process simulation is presented. Individual components of the proposed software tool are described and the principal methodology of their function is explained. As the simulation engine, commercial process simulator Aspen HYSYS was employed. Proposed tool was applied to a case study of an ammonia synthesis plant based on an existing plant. Hazardous events and operability problems in the syngas purification unit and ammonia synthesis loop have been detected and reported. The steady state multiplicity phenomenon in the ammonia synthesis loop has also been successfully identified. Based on simulation data evaluation performed in the semi-automatic manner by the proposed tool, a HAZOP-like report containing HAZOP deviations and their causes and consequences was generated. (C) 2018 Elsevier Ltd. All rights reserved.

One of the most complex technologies to upgrade heavy oil residues into more valuable products is their hydrocracking in a three phase gas-liquid-solid system in an ebulated-bed reactor. This paper summarizes the development cycle of an upgraded temperature control system for such hydrocracking unit, specifically for an industrial hydrocracking cascade system consisting of three ebulated-bed RHC (Residual HydroCracker) reactors connected in series. In the first phase, review and testing of different mathematical interpolation methods to create continuous temperature profile across the reactor from measured data points were conducted. Second step represented the selection of optimum visualization technique for the purposes of process operation based on the calculation requirements and discussions with process engineers and operators experienced with operation of studied RHC unit. In the final phase, software tool implementing selected methods was developed. The developed tool was readily available to be included into the process operation software system and it was quickly adapted into operating practice.

This paper discusses the framework methodology behind the proposed simulation-based HAZOP tool. Simulation-based approach is one of the many ways to support conventional HAZOP by its automation. Compared to knowledge-based and other approaches, a HAZOP software tool based on deviations simulation is able to examine the investigated process more into detail and so find root causes of hazardous consequences. Another advantage is the ability to identify also potential hazards which did not occur in the past and might be overlooked. The presented framework methodology uses a layer of protection analysis (LOPA) concept of independent protection layers (IPLs) testing. Control system integrated into the raw process design represents the first of various protection layers of the LOPA concept. As a case study, a CSTR chemical production with nonlinear behavior under Proportional-Integral-Derivative (PID) actions as the predominant type of classical feedback control strategy is used. The presented tool identifies hazardous regimes under conditions when control loop introduces hazardous consequences or even acts synergically with existing hazardous events. Risk derived from different consequences is ranked by the risk assessment matrix (RAM) as a part of the conventional quantitative HAZOP study.

Computer-aided process engineering provides industrially widely applied software solutions that can be successfully exploited for safety analysis. In this work, simulation-based hazard identification tool with demonstrative applications is proposed. HAZOP study was selected as the base methodology and commercial simulator Aspen HYSYS was employed as the simulation environment. Two case studies, ammonia synthesis plant and propylene glycol production, differing in employed unit operations were selected to determine robustness and reliability of the proposed tool. Hazards and operability problems were identified utilizing advanced mathematical algorithms such as parametric sensitivity analysis coupled with runaway effect detection and steady state multiplicity identification. Reactive systems of both case studies are well known for their nonlinear behavior and the presence of steady state multiplicity. This phenomenon was successfully simulated using Aspen HYSYS built-in solver.

This paper discusses the relation between hazard and operability study - HAZOP, mathematical modelling of process and process control presented as the first layer of protection within general Layer of protection analysis (LOPA). In this work, these aspects are integrated in a new concept of automated software tool to provide hazard identification and operability study of the investigated process. The main benefit of this approach is its ability to perform detailed safety analysis for systems operated near or within nonlinear behaviour regimes which involve process control and so enhance the simulation-based HAZOP technique. This concept is also able to identify hazardous regimes under conditions when control loop bring unpredictable situations or even acts synergic and so to provide validation of the applied process control itself. In the presented analysis, both steady state and dynamic analysis are integrated in the methodology. The concept is applied on the CSTR chemical production process under Proportional-Integral-Derivative (PID) actions.

This paper discusses the relation between hazard and operability study – HAZOP, mathematical modeling of processes and process control presented as the first layer of protection within general Layer of protection analysis (LOPA). In this work, these aspects are integrated in a new concept of hazard identification and operability study of the investigated process and both, steady state and dynamic, analyses are integrated in the methodology. The concept is able to identify hazardous regimes caused by parameter disturbances itself and also those when inappropriate control loop actions act synergic with already present disturbances. Thus, validation of the applied process control is provided. The concept is applied for the CSTR chemical process of catalyzed propylene glycol production under Proportional-Integral-Derivative (PID) actions. Under the investigated conditions, the process is characterized by the presence of strong nonlinearity and multiple steady state phenomena, which unpredictably affect the process control actions. Some hazardous events and operability issues were identified by the presented methodology and corrective actions were proposed.

This paper discusses the role of process modeling in safety analysis. Process modeling is applied in the fault propagation behavior study of CSTR chemical production. For that purpose, HAZOP methodology and continuation analysis were used. The proposed hazard identification methodology involves analysis of steady-state multiplicity and safe operating conditions as well as those which can shift process units from one steady state to another. All presented case studies are also supported by system dynamic simulations, essential to detect oscillatory thermal instability. In this paper, N-oxide alkylpyridines production process was chosen to identify potential hazard and operational problems. Presented dynamic simulations represent an analysis of the system response to step changes in the key operating parameters. The effect of deviations of three key parameters on the reactor safe operation was investigated. The proposed numerical algorithms represent a mathematical engine of the simulation module within an automated model-based HAZOP analysis tool.

Process hazard analysis techniques are often very time-consuming tasks requiring experienced expert teams and thorough discussion meetings. Software tools for computer assistance in process hazard identification seems to be essential for the enhancement of these techniques and thus for the reduction of their time and labour requirements. Our work is focused on the development of such software tools implementing HAZOP (HAZard and OPerability) study and process simulations based on complex mathematical models. In this paper, challenges in hazard identification automation are discussed. Issues such as mathematical model parameter uncertainties and their impact on the safety analysis results, interpretation variability of quantitative HAZOP deviations for process simulations, limitations of built-in solvers in commercial process simulators for safety analysis and computing time dependence on the complexity of the mathematical model are discussed. As a part of this contribution, review of the application of a software tool developed by our research to novel industrial plants is demonstrated. Mathematical models of the considered case studies had various depths and included not only a reaction step, but also feed preparation and products separation steps. Output from the simulation-based HAZOP study carried out by the proposed tool is a simplified HAZOP-like report consisting of analysed HAZOP deviations and classification of their consequences.

Implementation of computer aided approach into hazard and operability (HAZOP) study is one of the most researched topics in the field of hazard identification improvement. However, acceptance of an automated HAZOP tool in the industrial practice is limited. This contribution provides retrospective analysis of application issues connected with the use of process simulations in computer aided HAZOP studies. As case studies, mathematical models utilising different sets of unit operations, e.g. plug flow reactor, continuous stirred-tank reactor, phase separator, heat exchanger etc. were analysed. Two different simulation platforms, commercial process simulator Aspen HYSYS and our own mathematical models in MATLAB, were employed. Relevant concerns regarding the use of process simulations in the HAZOP study such as model reliability and its parameter uncertainties effect on the HAZOP study output and interpretation variability of quantitative HAZOP deviations for process simulations are discussed. It is demonstrated that the application of process simulation is a feasible way to perform precise safety analyses of processes widely used in chemical industry. However, proper attention has to be paid to the construction and use of mathematical models in order to develop a suitable software solution.

This study combines Monte Carlo based process simulation features with classical hazard identification techniques for consequences of deviations from normal operating conditions investigation and process safety examination. A Monte Carlo based method has been used to sample and evaluate different deviations in process parameters simultaneously, thereby bringing an improvement to the Hazard and Operability study (HAZOP), which normally considers only one at a time deviation in process parameters. Furthermore, Monte Carlo filtering was then used to identify operability and hazard issues including inefficient, uneconomical and unsafe conditions. Appropriate process modifications to mitigate deviations from normal operation ensuring process safety are also provided.

To satisfy the ever-growing needs of modern civilization, society and industry are experiencing transformation through automation and digitalization. The present work deals with process safety automation issues in chemical industry with a particular focus on computer aided hazard identification based on mathematical modeling and process simulation. In this paper, a smart software system solution combining HAZOP (HAZard and OPerability) study principles and computer simulation of complex industrial processes employing Aspen HYSYS is proposed. An ammonia industrial production unit has been chosen as a case study to demonstrate the applicability and application procedure of the proposed software tool for model-based HAZOP study. The results also indicate that the proposed software tool can supplement process design and intensification studies employing Aspen HYSYS.

At present, the likelihood of accidents linked with hazardous materials release is an increasing problem due to the intensification of industrial production and enormous increase of the risk of terrorist attacks. Organizations responsible for emergency planning have to be prepared for real-time consequence analysis. Accurate predictions and appropriate decision can significantly minimize the impact of accidental release of hazardous materials. Consequence analysis requires the access to extensive amounts of information, and its application without appropriate software and hardware infrastructure is nowadays quite unreal, therefore, utilization of a smart software framework seems to be the most straightforward procedure of hazard analysis. The presented submission is focused on the description of the design and development of a software framework used for fast prediction of the consequences of industrial accidents linked with the release of hazardous materials. Architecture of this framework involves the integration of an online meteorological system, GIS database and a consequence modeling subsystem.

Process safety is one of the key pillars of sustainable industrial development. In combination with the increasing use of computer aided process engineering, the demand for an appropriate model-based safety analysis tool capable to identify all hazardous situations leading to a major accident has increased. Commercial process simulators are equipped with extensive property databases and they employ high accuracy mathematical models providing the capability to simulate real behavior of a process operated within the area of the mathematical model validity. The main focus of this work is to improve standard hazard identification methods by the combination of hazard and operability (HAZOP) study and process simulation in commercial process simulator Aspen HYSYS. Software tool consisting of modules for computer simulation and complex analysis of simulation data will be proposed. The developed tool was applied to modern chemical productions exhibiting strong nonlinear behavior, where proper prediction of consequences can be very difficult. In the first case study, hazard identification in continuous glycerol nitration employing user-dependent analysis is presented. Mathematical methods of simulation data analysis independent of the user is demonstrated in the second case study of ammonia synthesis. Possibilities and limitations of the proposed tool are revealed and discussed in this work.