Showing papers in "Industrial & Engineering Chemistry Process Design and Development in 1976"

Reconcillation and Rectification of Process Flow and Inventory Data

Abstract: This paper shows how information inherent in the process constraints and measurement statistics can be used to enhance flow and inventory data. Two important graph-theoretic results are derived and used to simplify the reconciliation of conflicting data and the estimation of unmeasured process streams. The scheme was implemented and evaluated on a CDC-6400 computer. For a 32-node 61-stream problem, the results indicate a 42 to 60 % reduction in total absolute errors, for the three cases in which the number of measured streams were 36, 50, and 61 respectively. A gross error detection criterion based on nodal imbalances is proposed. This criterion can be evaluated prior to any reconciliation calculations and appeared to be effective for errors of 20 % or more for the simulation cases studied. A logically consistent scheme for identifying the error sources was developed using this criterion. Such a scheme could be used as a diagnostic aid in process analysis.

Coal liquefaction in coiled tube reactors

Abstract: Dry, powdered coal impregnated or mixed with 5 percent ZnCl/sub 2/ can be converted to liquid and gaseous products in small diameter coiled tubes. Yields to 70 percent (50 percent liquid, 20 percent primarily CH/sub 4/ gas) can be obtained at 500/sup 0/C and 1800 psi hydrogen pressures in /sup 3///sub 16/ in. i.d. stainless steel tubes 60 to 120 ft in length. The liquid portion is a complex mixture, principally aromatic which could serve as a synthetic crude petroleum for refinery feed stock. Procedures for catalyst recovery and/or recycle are indicated.

A quantitative design procedure for vertical pneumatic conveying systems

Abstract: In vertical pneumatic conveying, the task of the design engineer Is, for a given rate of conveying a particular solid, to specify pipe size, air flow rate, pressure drop, and flow pattern In the riser. In this paper a quantitative procedure for tackling this design problem Is outlined. The procedure Is an updated version of an earlier procedure presented by Leung et al. (1971a) and is based on recent advances on prediction of flow regime and pressure drop in vertical pneumatic conveying.

Process Optimization by Flow Sheet Simulation

Abstract: Muklenov, I. P.. Demshin, V. Y., Zh. Prikl. Khim., 28, 922 (1955). Pozin, M. E., Muklenov. I. P., Demshin. V. Y., Zh. Prikl. Khim., 28, 641 (1955). Quon, J. E., Phillips, R. A,, \"A Laboratory investigation of a Foam-phase Air Cleaning Device\", 5th Annual Sanitary and Water Resources Engineering Conference, Vanderbret University, 1966. Yano, T., Osawa, K.. Akita, M., KagakuKogaku, 10, (6), 301 (1955). (1940).

Magnetic Filtration of Small Heterogeneous Catalyst Particles. Preparation of Ferrimagnetic Catalyst Supports

Abstract: H,igh-gradient magnetic separation (HGMS) provides a very effective method of removing small (1-100 p) particles of certain heterogeneous catalysts from reaction mixtures. The preparations of magnetically responsive carbon-, silica-, and alumina-magnetite supports are described, and the behavior of these supports in magnetic filtration is summarized. Large-scale processes involving heterogeneous catalysis often require that the recovery of catalyst from product be very efficient, both to minimize loss of expensive catalyst components and to avoid contamination of products with catalyst. Large catalyst pellets can normally be retained in reactors or separated from products by conventional filtration or centrifugation techniques. The recovery of small catalyst particles-either used intentionally or formed by attrition from larger particles-is presently inefficient and expensive. Here we wish to report a general technique for the preparation of magnetically responsive, ferrimagnetic, supported heterogeneous catalysts, and to illustrate the usefulness of high-gradient magnetic separation (HGMS) techniques for separating these as well as ferromagnetic and certain paramagnetic catalyst particles from suspension. Ferro-, ferri-, and paramagnetic solids suspended in a diamagnetic liquid move in a magnetic field gradient toward regions of high magnetic field. The magnetic force acting on a particle is proportional, inter alia, to the magnitude of the gradient. HGMS depends on techniques, developed at the M.I.T. National Magnet Laboratory, which permit the generation of very high magnetic field gradients using very simple apparatus (Kolm et al. in the small-scale experiments carried out in this work, separations were carried out using a 50-ml buret containing a loosely packed plug (ca. 0.0b g) of 00 or 0000 steel wool, positioned between the poles of a magnet having 2.5-10-kG field strength. Large magnetic field gradients are generated close to the steel wool strands by their magnetization, and these high gradient regions act as efficient \"collectors\" for magnetic particles suspended in a liquid that is passed through the plug. Magnetic filtration of ferromagnetic and ferrimagnetic solids (e.g., Raney nickel and magnetite, vide infra) is easily accomplished at field strengths less than 5 kG. Magnetic filtration of paramagnetic solids is more difficult: very intense magnetic field gradients, moderately large paramag-netic susceptabilities, and a matching of the diameters of the particles and the steel wool strands is required (Ober-teufer, 197 4). Using field strengths sufficient to saturate steel (212 kG), gradients as great as 1 kG/p may be generated in a HGMS filter, if the strands of the steel wool are sufficiently fine: these gradients will …