THE BIFURCATION BEHAVIOR OF AN AUTOTHERMAL PACKED-BED TUBULAR REACTOR

The analysis of a chemical reactor by numerical bifurcation techniques can completely define the multiplicity and stability of its equilibrium states and can give insights into the reactor's parametric sensitivity and dynamical behavior in the neighborhood of the chosen operating points. In this paper, we will present some of the numerical bifurcation techniques used and developed in analyzing an autothermal packed bed tubular reactor. The bifurcation behavior found will be cataloged over the range of relevant reactant inlet conditions, and an explanation for the isolated solution branches characteristic of this reactor will also be presented.Endnote format citatio

STABILITY OF TUBULAR AND AUTOTHERMAL PACKED-BED REACTORS USING PHASE PLANE ANALYSIS

The regions of stability and parametric sensitivity of countercurrent reactor/heat exchangers are determined explicitly in the plane of inlet feed temperature-inlet coolant temperature. The concept of phase plane analysis is generalized to include all orders of reaction rate expressions, a broader range of system parameters, and is extended to the case of autothermal reactors. An industrial hydrocarbon oxidation reactor model and an autothermal CO oxidation reactor model have been used to illustrate and to evaluate the analysis method. The approach presented here is appealing since the region of safe inlet temperatures is determined explicitly and the region of safe operation can be optimized with respect to the reactor design parameters.Endnote format citatio

A Manual for Conducting Preliminary Environmental Site Assessments for Illinois Department of Transportation Infrastructure Projects

Illinois Department of Transportation contract #IDOT-2011-05568Ope

A manual for conducting preliminary environmental site assessments for Illinois Department of Transportation highway projects

Illinois Department of Transportation contract #IDOT-2011-05568Ope

EVALUATION OF BIOGENIC SUBSTANCES IN THE RIVER ŠVENTOJI / BIOGENINIŲ MEDŽIAGŲ KONCENTRACIJŲ NERIES INTAKE ŠVENTOJOJE VERTINIMAS

The article discusses the influence and main causes of nutrient compounds in surface waters. The article is aimed at investigating changes in nutrients – nitrogen and its compounds in the river Šventoji. The samples of analysis were collected in the town of Anykščiai in order to assess the influence of the stream of the Anykšta and waste water treatment. The largest concentrations of nutrients were identified from waste water treatment; however, it had not exceeded the MAC, except for February 2012. The conducted analysis has shown that the river Šventoji belongs to the class of a high ecological status, because physic – chemical quality elements such as nitrate – nitrogen (0,60 mg/l) and ammonium – nitrogen (0,03 mg/l) have not exceeded the range <1,30 mg/l and 0,10 mg/l. Santrauka Straipsnyje nagrinėjama biogeninių medžiagų įtaka paviršiniams vandens telkiniams ir pagrindinės šių medžiagų atsiradimo priežastys. Tyrimo tikslas – azoto turinčių biogeninių medžiagų – nitritų, nitratų, amonio koncentracijų Šventosios vandenyje analizė. Mėginiai buvo imti Anykščiuose ir už miesto ribų, įvertinta Anykštos upelio, komunalinių nuotekų valyklos įtaka Šventosios vandens užterštumui. Didžiausi biogeninių medžiagų kiekiai Šventojoje nustatyti už nuotekų valyklos, tačiau jie neviršijo DLK, išskyrus sausį. Pagal fizikinius-cheminius kokybės elementus – nitratų azotą (0,60 mg/l) ir amonio azotą (0,03 mg/l) Šventoji atitinka labai geros ir geros ekologinės būklės klasę, nes jos vandens kokybės reikšmės patenka atitinkamai į <0,10 mg/l ir 1,30–2,30 mg/l reikšmių intervalą. Reikšminiai žodžiai: biogeninės medžiagos, eutrofikacija, nitratų azotas, nitritų azotas, amoniakinis azotas