Refinery continuous plants

Essentially one stream of the old continuous refinery plant was demolished to make way for the installation of five 420 tonne pans, allowing batch refining to commence at reduced capacity. It was a significant achievement that single stream batch refining was successfully commissioned while operators lacked access to walk fully around three of the new pans. 

In Part IV, the mechanism of the proposed solution will be presented where integration with other components within PEEE will be explained in more details. This includes integration with the modeling environment (CAPE-ModE), RCM-based maintenance management system, fault detection system, design environment, and with operation support system. Case studies are selected from continuous chemical plant i.e. HDS plant, batch chemical plant i.e. PVC, and upstream end of oil refinery process to illustrate the proposed solution. 

Chemistry does not always enjoy the best of reputations. Many of our plants and refineries are still potentially dangerous and may pollute their surroundings. At the same time our society enjoys a high standard of living not in small measure through the results of chemistry, which few would give up. I believe that chemistry can and will be able to bring about an equilibrium between mankind s needs and our environmental concerns. Chemistry will continue to benefit mankind in the spirit of Alfred Nobel, a fellow chemist whose example continues to inspire us all. 

Production Controls The nature of the produc tion control logic differs greatly between continuous and batch plants. A good example of produc tion control in a continuous process is refineiy optimization. From the assay of the incoming crude oil, the values of the various possible refined products, the contractual commitments to dehver certain products, the performance measures of the various units within a refinery, and the hke, it is possible to determine the mix of produc ts that optimizes the economic return from processing this crude. The solution of this problem involves many relationships and constraints and is solved with techniques such as linear programming. 

Inert gas-filled motors can also be used in refineries and chemical plants, but their applications are limited. They have tightly fitted covers and oil seals around the shaft to minimize gas leakage, are continually pressurized with an inert gas or instrument air, and are equipped with an internal air-to-water heat exchanger. Inert gas-filled motors are suitable for any hazardous location but require auxiliaries such as cooling water, gas pressurizing system, and control accessories. 

Maintenance may be handled either by employees hired especially for that job or by an outside contractor. The latter is most economical when workers in most trades are needed only occasionally. The company does not need to hire these workers full time, but still has their talents available when they are needed. Even in a large plant where a number of employees skilled in each maintenance trade are needed full time, contract maintenance may be used as a supplement at times of turnarounds (a planned time when large continuous plants are shut down to do preventive maintenance, repairs, and inspections) or especially heavy demands. For instance, during the turnaround of a 140,000 bbl/day (22,000 m3/day) Tidewater Oil Company refinery, the number of maintenance personnel rose from a preshutdown level of 181 to 924 men.48 Fewer men could have been used, but the downtime of the refinery would have been increased. In this instance the plant contracted for all of its maintenance. 

Hypersorption A continuous chromatographic separation process using a moving bed. Invented in 1919 by F. D. Soddy (famed for his work on isotopes) at Oxford and developed commercially for petroleum refinery separations by the Union Oil Company of California in 1946. Six plants were built in the late 1940s, using activated carbon as the adsorbent. The process was abandoned because attrition of the bed particles proved uneconomic. 

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