The Effect of Magnetic Radiation on Pipeline Transportation of Crude Oil
The deposition of paraffin wax during the pipeline transportation impedes the flow of crude oil and eventually blocks the pipelines. The hot oiling method is extensively used to control the wax deposition in the oil industry. Consequently, a huge amount of energy is consumed to heat the crude oil by hot water or electrical power every year. In order to save the energy cost, the magnetic paraffin control technology is presented and evaluated with the hot oiling method, and accordingly the effect of the magnetic radiation on the oil transportation is detailed. The experiments carried out have demonstrated that the magnetic treatment can compensate for the resistance rising of the pipeline caused by the hot water reduction. Especially, the transportation of crude oil (at the surrounding temperature of -10°C~-30°C) without any heating has been observed in the Daqing oil field under the radiation of a magnetic field of 120 mT. In addition, the effect of the length of pipelines on the performance of magnetic treatment was also investigated.
Combined Effect of Pour Point Depressants and Magnetic Field on the Viscosity and Pour Point of Crude Oil
Pour point depressants (PPD) are widely used for mitigating wax deposition problems. But they are costly and environmentally hazardous. Another method which has attracted the attention is the magnetic field (MF) conditioning method. Though this method is environmentally friendly and economical, the results obtained have found to be controversial. The viscosity and pour point may increase or decrease. This has been attributed to number of reasons, the main reason being the specificity of crude oil and its interaction with the magnetic field. Hence an attempt has been made to investigate the combined effect of PPDs and MF for better viscosity and pour point reduction. It has been found that there is no substantial enhancement in the viscosity and pour point reduction with the combination. Hence pure PPD method dominates wax inhibition methods as of now.
Asymptotic Properties of Solutions to Second-Order Difference Equations of Volterra Type
<jats:p>We consider the discrete Volterra type equation of the form <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi mathvariant="normal">Δ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mi>n</mml:mi></mml:mrow></mml:msub><mml:mi mathvariant="normal">Δ</mml:mi><mml:msub><mml:mrow><mml:mi>x</mml:mi></mml:mrow><mml:mrow><mml:mi>n</mml:mi></mml:mrow></mml:msub><mml:mo stretchy="false">)</mml:mo><mml:mo>=</mml:mo><mml:msub><mml:mrow><mml:mi>b</mml:mi></mml:mrow><mml:mrow><mml:mi>n</mml:mi></mml:mrow></mml:msub><mml:mo>+</mml:mo><mml:mrow><mml:msubsup><mml:mo stretchy="false">∑</mml:mo><mml:mrow><mml:mi>k</mml:mi><mml:mo>=</mml:mo><mml:mn mathvariant="normal">1</mml:mn></mml:mrow><mml:mrow><mml:mi>n</mml:mi></mml:mrow></mml:msubsup><mml:mrow><mml:mi>K</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mi>n</mml:mi><mml:mo>,</mml:mo><mml:mi>k</mml:mi><mml:mo stretchy="false">)</mml:mo><mml:mi>f</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:msub><mml:mrow><mml:mi>x</mml:mi></mml:mrow><mml:mrow><mml:mi>k</mml:mi></mml:mrow></mml:msub><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:mrow></mml:math>. We present sufficient conditions for the existence of solutions with prescribed asymptotic behavior. Moreover, we study the asymptotic behavior of solutions. We use <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mi mathvariant="normal">o</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:msup><mml:mrow><mml:mi>n</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msup><mml:mo stretchy="false">)</mml:mo></mml:math>, for given nonpositive real <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:math>, as a measure of approximation.</jats:p>