Imran M.,Stone and Webster
Petroleum Technology Quarterly | Year: 2013
Strong ethane supplies are positioning the US as the most competitive, low-cost ethylene producer, resulting in increased investments in ethane recovery and pipelines. As a result, several companies have already announced their plans for major investments in the US ethylene sector. A discussion covers the factors to consider before deciding to shift to ethane feedstock; ethane cracking and products distribution; important consideration when converting a liquids furnace for ethane cracking; chilling train and expander/recompressor; and ethylene and propylene refrigeration compressors.
Lu G.,Stone and Webster |
Li X.,Central South University |
Wang K.,Iowa State University
Computers and Concrete | Year: 2012
This paper presents the numerical simulation of the rigid 12.6 mm diameter kinetic energy ogive-nosed projectile impact on plain and fiber reinforced concrete (FRC) targets with compressive strengths from 45 to 235 MPa, using a three-dimensional finite element code LS-DYNA. A combined dynamic constitutive model, describing the compressive and tensile damage of concrete, is implemented. A modified Johnson-Holmquist-Cook (MJHC) constitutive relationship and damage model are incorporated to simulate the concrete behavior under compression. A tensile damage model is added to the MJHC model to analyze the dynamic fracture behavior of concrete in tension, due to blast loading. As a consequence, the impact damage in targets made of plain and fiber reinforced concrete with same matrix material under same impact velocities (650 m/s) are obtained. Moreover, the damage distribution of concrete after penetration is procured to compare with the experimental results. Numerical simulations provide a reasonable prediction on concrete damage in both compression and tension.
Ratan S.,Stone and Webster
AIChE 2013 - 2013 AIChE Spring Meeting and 9th Global Congress on Process Safety, Conference Proceedings | Year: 2013
There is a strong drive for improving refinery profitability or margins through added-value options in order to lower the unit cost of hydrogen, and thereby improving overall economics of a hydrogen facility whether new or existing or under the 'make' or 'buy' scenarios, which eventually improves refinery margins. These options include advanced hydrogen management along with integrated utilization of refinery off-gas, augmentation of existing hydrogen capacity, economies of scale and strategic steam-power synergy. Most of these options carry inherent added merits of improved availability and reduced environmental impact. Some of these proven value-enhancement options are discussed and case histories providing potential reduction in net unit cost of (on-purpose) hydrogen and thus enhancing refinery's margins as well as its extrinsic economics are presented. This is an abstract of a paper presented at the 2013 AIChE Spring Meeting & 9th Global Congress on Process Safety (San Antonio, TX 4/28-5/2/2013).
Card R.W.,Stone and Webster
American Society of Mechanical Engineers, Power Division (Publication) POWER | Year: 2014
A hybrid wet-dry cooling system can reduce water consumption at a power plant while minimizing the performance penalty of an air-cooled condenser (ACC). Automatic allocation of turbine exhaust steam among the wet and dry sections provides robust performance. However, the performance test for the unit must be carefully designed to prove the guarantees for water conservation and thermal performance with minimal uncertainty. A hybrid wet-dry cooling system of the "parallel" type is modeled based on recently-constructed power plants. Effects of typical off-design test conditions are demonstrated. Techniques are recommended for designing an effective performance test for a hybrid wet-dry cooling system based on the use of existing Performance Test Codes (PTC). Copyright © 2014 by ASME.
Stone and Webster | Date: 2011-01-14
The present disclosure enables phenol recovery, purification and recycle in a simple, economic manner from waste streams from, for example, a phenol/acetone production process, e.g., a phenol/acetone plant or an upstream cumene hydroperoxide cleavage process step, and BPA production step, for use in the reaction with acetone to produce BPA. The disclosure therefore reduces the overall consumption of phenol in the production of BPA.