Search

Steam-cracking is energetically intensive large-scaled process which transforms a wide range of hydrocarbons feedstock to petrochemical products. The dependence of products yields on feedstock composition and reaction conditions has been successfully described by mathematical models which are very useful tools for the optimization of cracker operation. Remaining problem is to formulate objective function for such an optimization. Quantitative criterion based on the process economy is proposed in this paper. Previously developed and verified industrial steam-cracking semi-mechanistic model is utilized as supporting tool for economic evaluation of selected gasoline feedstock. Economic criterion is established as the difference between value of products obtained by cracking of studied feedstock under given conditions and the value of products obtained by cracking of reference feedstock under reference conditions. As an example of method utilization, optimal reaction conditions were searched for each of selected feedstock. Potential benefit of individual cracking and cracking of grouped feedstocks in the contrast to cracking under the middle of optimums is evaluated and also compared to cracking under usual conditions.

A heavy side‐product of the Fischer‐Tropsch (FT) process called waxes are potential renewable feedstocks for the steam‐cracking process. Samples of FT wax and distillation cuts thereof were investigated using laboratory pyrolysis in order to compare their pyrolysis performance with traditional steam‐cracking feedstocks, i.e., primary naphtha and hydrocracking products. At 815 °C, waxes provided significantly higher yields of the desired products ethylene and propylene, and lower yields of oil compared to traditional feedstocks. The yields of waxes blended in traditional feedstocks and the sensitivity of cracking product yields to temperature and residence time were also examined experimentally. [ABSTRACT FROM AUTHOR]

The work was aimed at the evaluation of a cleanliness of pharmaceutical equipments after the end of the production and subsequent cleaning process. The influence of a dirty-hold time, a time interval between the end of the production period and the beginning of the cleaning process on its efficiency and the cleanliness of the equipment has been studied. The evaluation was performed for commercial tablet antihypertensive formulation with API losartan potassium. Sampling was carried out by a wet-swabbing method from the equipments and consequently obtained samples were analytically evaluated using HPLC. In the production of the concerned pharmaceutical, it has been found that the cleaning process is properly designed and validated. Despite the concentration of losartan in swabs from the equipment was in all cases within the limits of acceptance criteria, the effect of the dirty-hold time was proved. In the equipments with long hold-time period, the monitored substance was found in substantially higher concentrations. [ABSTRACT FROM AUTHOR]

Abstract: Petroleum fractions are typical complex mixtures. For the simulation of petroleum refining processes they are characterized by substitute mixtures. In this contribution the traditional approach based on pseudocomponents is compared with the newer approach utilizing a Substitute Mixtures of Real Components (SMRCs). The main advantage of SMRC approach is the direct availability of physical property data and the knowledge of the chemical character. The most important task in many applications is to characterize the C7+ fraction. It is shown, how it can be characterized by a small number of real components. The examples used for comparison comprise separation processes and also the pyrolysis modeling, where the known chemical character of a SMRC is crucial for feeding an artificial neural network model. [Copyright &y& Elsevier]