Process-scale considerations location

Consideration of alternatives seeks to ensure that the proposer has considered other feasible options including location, scales, processes, layouts, operating conditions and the no action option. 

Interest has continued in on-site manufacture of hydrogen peroxide from the elements, particularly for remote sites located considerable distances from wodd-scale anthraquinone processes. However, no commercial-scale direct combination plants have been constmcted as of this writing. 

Sample Withdrawal from Process A number of considerations are involved in the design of sample-withdrawal devices that wih provide representative samples. For example, in a horizontal pipe that conveys process fluid, a sample point on the bottom of the pipe wih collect a maximum amount of rust, scale, or other solid materials being carried along by the process fluid. In a gas stream, such a location will also collect a maximum amount of liquid contaminants. A sample point on the top side of a pipe will, for liquid streams, collec t a... 

Scale-up can also have a significant effect on the basic process control system and safety systems in a reactive process. In particular, a larger process will likely require more temperature sensors at different locations in the process to be able to rapidly detect the onset of out-of-control situations. Consideration should be given to the impact of higher-temperature gradients in plant-scale equipment compared to a laboratory or pilot plant reactor (Hendershot 2002). 

At industrial scale, careful consideration of the materials of construction for the bioseparation equipment is vital to ensure that the product does not become contaminated, by rust, for example, and also to assure long plant life with good reliability to maximize throughput. Materials that were suitable on a laboratory or pilot scale may no longer be appropriate, where the process and mechanical demands on the equipment may be greater. For example, the plant could be located outside where there are greater extremes of temperature in summer and winter, or equipment may need to be steam sterilized in situ rather than being autoclaved. 

There are four primary reasons why the mechanical extraction process is still selectively used. First, the mechanical extraction process can be furnished in very small scale, as low as 10 tons per day. The capital cost for small mechanical extraction facilities is considerably less than small solvent extraction facilities. In remote locations, freight differential can compensate for higher operating costs and lower yields. Second, there is a niche, high-value market for natural oils that have not been in contact with solvents or chemicals, requiring the use of mechanical extraction. Third, mechanical extraction can create a high bypass protein meal for ruminant animals that sells at a price premium over solvent extracted meal. Finally, mechanical extraction is often considered more reliable than solvent extraction when processing difficult materials (copra and palm kernel) in hot, tropical climates. 

Automated systems have several potential advantages over classical technical labor. Analytical functions are reproduced on a programmed schedule, reducing the turnaround time of the samples and enabling a more reliable estimate of analytical costs. In addition to the accuracy of the equipment, costs are readily estimated, the process is easier to scale up or down, and process parameters can be more easily varied in an understandable way. Automated systems can produce data from worldwide locations and may be readily standardized and compared. Manual operation remains preferable for procedures that require considerable judgment in the selection of alternatives. 

Within the design consideration factor, probably the most important section is plant layout. Taking into account the possibility of dust explosion and fire, a question arises whether a certain type of plant may be located in a particular place or whether some splitting of the process on particular operations may be required. The increased scale of many new industrial plants means that the volume of the plant providing a risk of explosion is much greater than it was only a few years ago. 

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