DNV GL

About: DNV GL is a company organization based out in Sandvika, Norway. It is known for research contribution in the topics: Corrosion & Finite element method. The organization has 1929 authors who have published 2387 publications receiving 34644 citations.

Evaluation of Multiphase Flow Rate Models for Chokes Under Subcritical Oil/Gas/Water Flow Conditions

Abstract: Knowing the mass flow rate is important in relation to production control in the oil and gas industry. If the change in pressure and temperature across a choke can be correlated with the mass flow rate, the actuator position, and the properties of the well stream, this may constitute a mass flow rate meter that is both simple and inexpensive compared to other designs. However, knowledge of the predictive ability and accuracy of available mass flow rate models is required to qualify such a solution. Predictions from several mass flow rate models are compared with data from a crude oil/natural gas/water system at pressures varying from 8 to 16 bara. The fluids used were recombined oil from the Njord field in the North Sea, natural gas from the Kaarstoe terminal in Norway, and water with added salts to give typical produced-water properties. Two different choke geometries (orifice and cage type) were tested for three different opening areas. The experimental results are compared with eight mass flow rate models for multiphase flow through chokes. These are the two Hydro models originally developed by Selmer-Olsen, the Sachdeva et al. model. the Perkins' model, and four two-phase multiplier models-the Morris, the Chisholm, the Simpson, and the homogeneous equilibrium model (HEM), respectively. For the orifice-type geometry, the Hydro short model predicted the results most accurately. For the cage-type geometry, the Hydro long model, which includes losses in the choke geometry, predicted the results most accurately. A modification to the slip model improves the results of the Hydro models, predicting all the 367 test points with a standard deviation of 7.8%. The average error of absolute values was 5.8%.

Repurposing Used Electric Car Batteries: A Review of Options

Abstract: In the United States, millions of electric and hybrid vehicles have cumulatively been sold Although the batteries in these vehicles are expected to last at least 8 years, end-of-life options must still be considered There are several possible options for battery packs from electric vehicles when they reach end-of-life, including remanufacturing, repurposing for a different application, and recycling Remanufacturing is the most desirable end-of-life scenario but is the most stringent in terms of battery quality Recycling is less desirable because there are larger material and energy losses that occur in the process Repurposing batteries for a different use lies between these two scenarios in terms of desirability This review paper focuses on non-automotive reuse and explores several options for using electric car battery packs in grid energy storage applications

Environmental Issues and Financial Reporting Trends: A Survey in the Chemical and Oil & Gas Industries

Abstract: As environmental performance is increasingly seen to have an influence over financial performance and financial risk assessment, disclosure of environmental issues in the Annual Reports is a fundamental requirement for a company in order to satisfy the information needs of its stakeholders. Given this pressure there is a definite trend among leading companies to report their environmental performances within the financial statements, but the way companies disclose environmental-related information varies from company to company and from country to country. Besides, the qualitative level of this kind of disclosure, in term of relevance, comparability and credibility, is not generally very high. More and more voluntary and regulatory guidelines are emerging to encourage companies to disclose environmental issues in Annual Report. The aim of this paper is to examine literature relating to environmental disclosures in the Annual Report and to identify this environmental disclosure, but also its location and typology, thereby defining current practices on environmental reporting in Annual Reports of selected firms in the chemical and oil & gas industries.