Vibration Analysis of Heat Exchangers of a Nitric Acid Plant

This paper deals with an operational problem of two heat exchangers of the nitric acid synthesis plant. Detailed calculation and vibration analysis were made and vibration problem of the nitrous gases cooler E-111 was identified. When the vibration problem was indicated, several steps were taken for its removal. For five different types of baffles a study was made to determine how their number and spacing influence the cross-flow rate of the fluid. Results showed that the vibration problem cannot be removed completely, but it can be reduced considerably with different types of baffles. Also, the analysis showed that the cooling water condenser E-114 does not have a vibration problem

Vibration Analysis of Heat Exchangers of a Nitric Acid Plant

This paper deals with an operational problem of two heat exchangers of the nitric acid synthesis plant. Detailed calculation and vibration analysis were made and vibration problem of the nitrous gases cooler E-111 was identified. When the vibration problem was indicated, several steps were taken for its removal. For five different types of baffles a study was made to determine how their number and spacing influence the cross-flow rate of the fluid. Results showed that the vibration problem cannot be removed completely, but it can be reduced considerably with different types of baffles. Also, the analysis showed that the cooling water condenser E-114 does not have a vibration problem

Analysis of Cooling Water Systems in a Petroleum Refinery

An important area in process integration is the development of methodologies to minimize water and energy use in industry. More than 20 % of the energy consumption in industry is associated with cooling and heating water. This paper presents analysis and optimization of a re-circulating cooling water system, with the aim to satisfy any supply conditions for the cooling tower. The part of the atmospheric crude oil distillation unit was chosen for analysis and synthesis of cooling water systems by the Kim and Smith design (KSD) method. The load of the cooling tower and the cost related to the cooling water system could be reduced by modifying the configuration of the heat exchanger network. In this paper, the KSD methodology for a developed heat exchanger network is expanded with the principle based on the heuristic algorithmic water sources diagram procedure (WSD) to synthesize the mass exchange network. These procedures are advantageous compared with other methodologies since hand calculation is used, a very useful feature for process engineers. The cooling water network was synthesized, leading to a 40 % reduction in cooling tower load, and consequently, lower operating costs and water consumption

Urea Synthesis Plant - Process Water Treatment

Tijekom godina rada uočeno je da se proces proizvodnje uree poduzeća Petrokemija d. d. iz Kutine može poboljšati na nekoliko mjesta, pa tako i na sekciji za obradu otpadne vode. Cilj ovoga rada je poboljšanje toga dijela procesa s ekonomskog i ekološkog gledišta koje bi se moglo implementirati unutar postojećeg postrojenja. Provedena je analiza postojećeg stanja postrojenja UREA 2 i predloženo je novo rješenje koje daje zadovoljavajuće rezultate. Napravljena je analiza osjetljivosti veličina procesa koji utječu na količinu amonijaka i uree na izlazu iz sekcije za obradu vode. Kod analize postojećeg stanja i predloženog novog rješenja primijenjen je programski sustav ChemCAD.After the years of operation of Petrokemija d. d. from Kutina it has been recognized that the technology of urea production can be improved at several points, including wastewater treatment. The wastewater treatment area is a part of the urea plant, Urea 2 of Petrokemija d. d., Kutina. The plant has been in operation since 1983 based on the licensed Stamicarbon CO2 stripping process. So far there have been no major process improvements in terms of utility savings. This part of the plant releases into the environment almost 800 t per day of superfluous wastewater polluted with small, however significant, amounts of urea and ammonium. As such, this wastewater cannot be used in any other segment of urea production. The aim of this paper is to improve the current process from the economical and ecological point of view with ultimate goal of implementing the results obtained. Using the CHEMCAD program, the wastewater treatment section of the UREA 2 plant at Petrokemija d. d. Kutina was simulated. Sensitivity analysis of the parameters which influence the concentrations of ammonia and urea in the stream leaving the water treatment section was performe

Hydraulic Design of Thermally Coupled Columns and a DWC for NGL Fractionation Plants

Combining a conventional demethanizer with thermally coupled deethanizer and propane-butane recovery columns or a three-product dividing wall column (DWC) provides a realistic opportunity for natural gas liquids (NGL) fractionation complexes as encountered in floating, as well as on-land natural gas liquefaction plants, to minimize energy requirements and reduce carbon dioxide emissions accordingly, in a cost-effective way. The present paper addresses and discusses hydraulic design aspects of these two thermal coupling arrangements, including the choice of the most appropriate column internals that largely depends on important design, construction, and operating considerations that differ for floating and on-land plants

Blood lead levels in children living close to the antimony and lead mining-milling-smelting complex in Serbia

Objective of this cross-sectional study was to determine blood lead concentrations in children, living in the vicinity of the Zajača lead-antimony mining-milling-smelting complex. Other aims were to compare blood lead levels (BLLs) of exposed children to those of partially exposed and non-exposed, and correlate values of BLLs from two consecutive sampling series in 2012 and 2013. Performed laboratory method was atomic absorption spectrometry (AAS). Statistical significance of comparisons was tested by univariate methods and non-parametric tests for the attributable variables: Hi-square test, proportion test. In the case of non-parametric variables, following tests were used: Kolmogorov-Smirnov Z test for testing distribution's normality; ANOVA for the normal distribution, while a Kruskal Wallis Test was used in cases without normal distribution. 142 participants were tested on lead in blood: exposed, partially exposed, and non-exposed). Mean BLLs in children living at less than 1 km from the smelter was 18.98 µg/dl , at first test series, and 12.21 µg/dl, in the second round. For those living further than 3 km mean BLLs at first series was 8.30, and at the second series it was 5.85). Blood lead concentrations in children from Zajača are highest

SEMEN COLLECTION AND CONSERVATION OF BULLS SEMEN PODOL TYPE CATTLE

Semen collection, artificial vagina, electro-ejaculation, freeze semen We tray to collection ejaculates from bulls Podol Type Cattle with artificial vagina. Fantoms for collecting were cows in heat from the same herd or from another herd. We were not successafuly. With electro-ejaculation we collected ejaculates from bulls Podol Type Cattle and freeze semen in our Institute or in field

Studying large plainchant corpora using chant21

We present chant21, a Python package to support the plainchant formats gabc and Volpiano in music21, and two large corpora of plainchant. The CantusCorpus contains over 60,000 medieval melodies collected from the Cantus database, encoded in the Volpiano typeface. The GregoBaseCorpus contains over 9,000 transcriptions from more recent chant books in the gabc format. Chant21 converts both formats to music21, while retaining the textual structure of the chant: its division in sections, words, syllables and neumes. We present two case studies. First, we report evidence for the melodic arch hypothesis from the GregoBaseCorpus. Second, we analyze connections between differentiæ and antiphon openings in the CantusCorpus, and show that the systematicity of the connection can be quantified using an entropy-based measure