473 research outputs found
Simulation of heat transfer in the convection section of fired process heaters
Heat transfer analysis of the radiation section in a fired process heater was carried out in order to determine the flue gas and process fluid temperatures in the zone separating the convection and the radiation sections. Such a determination is a pre-requisite for the heat transfer analysis of the convection section.
A Matlab computer programme for the heat transfer analysis of the convection section was written and the results presented graphically including process heat load, the amount of absorbed heat per layer in the convection section and the temperature profiles of combustion gases, tube wall and process fluid
Matlab program computes thermal efficiency of fired heater
Two basic methods are normally employed for the calculation and estimation of the thermal efficiency of fired heaters, viz. the direct and the indirect methods, where the net calorific value is used in the former and the gross calorific value is used in the latter. Two Matlab programmes based on these methods were written and applied for the calculation of the thermal efficiency of a crude oil heater. The results are presented in the form of Sankey diagrams
EFFECT OF THE REMOVAL OF SULPHUR AND VOLATILE MATTER ON THE TRUE DENSITY OF PETROLEUM COKE
The true density of petroleum coke is a factor of its structure
and properties. As the removal of volatile matter and sulphur from the coke is
accompanied by significant changes in its structure and microporosity,
changes in its density are to be expected. In this paper, the effects of the
removal of volatile matter and sulphur on the true density of petroleum coke
were investigated. The density was found to increase significantly with the
evaporation of the volatile matter as a result of the thermal treatment of
the coke at a temperature of 1200 K. Removal of part of the sulphur in the
coke led also to a significant increase in the value of its true density.
Temperatures greater than 1600 K were necessary for effective sulphur
removal
THE EFFECT OF INCREASED RESIDENCE TIME ON THE THERMAL DESULPHURIZATION OF SYRIAN PETROLEUM COKE
High sulphur Syrian delayed petroleum coke was thermally treated at
high temperatures in order to reduce its sulphur content. It was found that
the high temperature required for effective desulphurization can be
reduced by increasing the residence time at the maximum heating temperature,
avoiding thereby the adverse effects associated with thermal treatment at
high temperatures, particularly in the case of the high sulphur Syrian coke.
A maximum desulphurization of 90\% was possible at a temperature of 1700 K
and a residence time of 180 minutes
Mapping 123 million neonatal, infant and child deaths between 2000 and 2017
Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations
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