Werner Witt

Brandenburg University of Technology Cottbus - Senftenberg | BTU · Chair of Plant Design and Safety Technology

A combination of a residual film of flammable organic substance, air and structured packing may result in a fire during maintenance, at start up or after shut down. The self-ignition temperature depends on the substance (reactivity, volatility), construction and geometry of packing, heat loss conditions and accident scenario. In this article a dyna...

A combination of a residual film of flammable organic substance, air and porous structures like insulation material (e.g. stone wool) may result in a fire. The initiating self-heating process depends on the substance (reactivity, volatility), amount of accumulated liquid, volume and temperature. Specific information is given for application and ext...

This investigation proposes a systematic framework based on the Fault Tree analysis, for the energy and exergy optimization of a paper machine. In the first step, energy and exergy analysis was performed on the dryer section and its related steam and condensate system, to assess the existing performance of paper machine. In the next step, checklist...

Industrial heat pumps are heat-recovery systems that allow the temperature of waste-heat stream to be increased to a higher, more efficient temperature. Consequently, heat pumps can improve energy efficiency in industrial processes as well as energy savings when conventional passive-heat recovery is not possible. In this paper, possible ways of sav...

Industrial heat pumps are heat-recovery systems that allow the temperature of waste-heat stream to be increased to a higher, more efficient temperature. Consequently, heat pumps can improve energy efficiency in industrial processes as well as energy savings when conventional passive-heat recovery is not possible. In this paper, possible ways of sav...

Hydrogen is an emerging alternative fuel, yet its properties like wide flammability range, extremely fast burning rate (order of magnitude larger compared to natural gas) and the considerably high amount of energy released when it burns or explodes render it as dangerous, if not handled with care. Hydrogen Incident Reporting Database (HIRD) is one...

Vapor−liquid equilibrium (VLE) measurements have been made for the binary systems ethene oxide + dodecane at four temperatures from (303.15 to 393.15) K, ethene oxide + 1-decanol at three temperatures from (303.15 to 363.15) K, and ethene oxide + 1-dodecanol at four temperatures from (313.15 to 433.15) K for varying mole fractions. An adiabatic cal...

A packed reactive distillation column producing ethyl tert-butyl ether from tert-butyl alcohol and ethanol was simulated for detection of multiple steady states using Aspen Plus®. A rate-based approach was used to make the simulation model more realistic. A base-case was first developed and fine-tuned to fit experimental data. Sensitivity analyses...

This article describes the investigation of an incident of catastrophic failure of a primary reformer in an ammonia plant. The lessons learned from the root cause analysis of the event are of interest. The reformer is one of the critical unit operation in an ammonia plant. Under normal operating conditions, reformer tubes get aged and progressively...

Process safety and cost are major considerations during the design of process plant and its projected operation. It involves critical decision making for the best choice. A cost-benefit analysis is usually carried out to facilitate this activity. However the final decision rest with the engineer. In this article, a systematic procedure based on mul...

Increasing social pressure and strict legislations have resulted in changing the approach of traditional design practices to incorporate multiple objectives in the design of process plants. Distillation is one of the major operations in the chemical process industry that is widely used for purifying products or recovering solvents or separation of...

Waste solvents/valuable products in the effluent stream are one of the major environmental problems in the chemical industry if not properly controlled. Separation processes are vital for the recovery of waste solvent/valuable product from the effluent stream to reduce the pollution along with improvement in economic performance. Among the various...

There is a clear link between safety and reliability in system design and operation. So the knowledge about sources of failure, their physical consequence related to plant operation and the frequency of effects (incident consequence) is of great value for improvement. Next, the selection of best improvement alternative should be justified by comple...

Process safety has a high priority in the chemical industry. And the distillation is the most widely used unit operation in the chemical-processing industries. The use of dynamic simulation for safety-related studies for a distillation column has great significance for the study of operational failures. In this article, a systematic framework based...

Equipment failures or faults in process occur as a result of complex interaction of the individual components and may lead to events that result in incipient faults, near misses, incidents and accidents in chemical plant (1). Protection systems are often in place as prevention barriers e.g. alarms, shutdown systems etc. These protective systems may...

In this paper, energy and exergy analyses of a distillation unit is conducted to study thermodynamic efficiency of the unit, performance evaluation and total annualized cost (TAC) optimization. A systematic procedure for analysis as well as optimization have been proposed and demonstrated by two case studies. The feed location, side stream withdraw...

Process safety is paramount in the secure and viable operation of any chemical process plant. Many techniques and methodologies have been defined over the years to undertake steps that will ensure a safe operating environment at a chemical facility. However, until now, process simulation has found very little or no use in safety-related studies. Th...

For solving multiobjective decision making problems, which may arise during optimization of operating or design of process plants, a systematic and effective procedure is required. As far as the process or control system has to be modified process simulators like Aspen Plus are widely used. But these simulators are not designed for investigation of...

The periodic behaviour of a heterogeneous isothermal catalytic reactor involving a single irreversible reaction based on the Langmuir–Hinshelwood mechanism is studied. Square-wave concentration cycling of the reactants is used as the reactor input. The nonlinear behaviour of the reactor is analysed by using a special function developed in the prese...

Risks of multiphase processes are based on the interaction between mass transfer, kinetics of chemical reactions, phase equilibrium and multiphase heat transfer. It is not sufficient to consider only kinetic terms in safety analysis of these processes. Besides events taking place in the reactor, all important devices in the reactor periphery (heat...

For the simulation of steady- and non-steady-state behaiour of separation columns, a simulation program was developed and employed for the calculation and optimization of methanol-water separation. The demand for increasingly higher purities and energy-saving optimization of plants results in complex column configurations and thus in complex contro...

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