Analysis of process streams

Service - Chemicals are still purchased on a price per kilogram basis. The supplier offers additional services such as just-in-time delivery, direct electronic ordering via an Electronic Data Interface, routine analysis of process streams and advice on chemicals usage, etc. The supplier still has an incentive to sell more chemicals, but does have more to lose should the end user change supplier. 

Computers continued to get smaller, faster, and cheaper. The accuracy and speed of chemical analysis continued to improve. With real-time chemical analysis of process streams and a mathematical model for each unit in the process, the computer was programmed to set controllers on process streams using the new process control algorithms. With some additional programming and with the process control set points adjusted by the computer control system, the quality of the product improved. The physical property data for the chemicals in the process streams required for these model calculations were built into the process control program. 

Optical spectroscopies are appropriate for many process analysis applications because they can provide a rapid analysis of process stream composition in an industrially robust form requiring little regular maintenance. On-line implementation means that extracting manual samples is avoided and results obtained using computerized data handling methods can be hnked to automatic control schemes. Recently a review of spectroscopy in process analysis has been published which contains descriptions and describes applications of optical spectroscopies [2]. 

Detailed reviews of oil refining corrosion problems and control methods are given in a book by White and Ehmke [78]. Oil refining corrosion problems are generally solved by making appropriate materials selection based on accumulated industry experience as reflected in published papers plus API and NACE committee reports. Neutralization and inhibition are used in some cases. Monitoring is generally by inspection supplemented by analysis of process streams (e.g., acidity) and by special probes. 

FUm-forming inhibitors, as distinguished from ammonia and other volatile amines, are considered to be non-volatile accordingly, in any gas-liquid separation process, they remain with the liquid and so may be concentrated in the heavy fractions of a refinery process. The efficacy of an inhibitor treatment or other process changes in controlling corrosion should be followed in refinery work by use of corrosion test coupons or spools, corrosion rate meters, corrosion resistance probes and by analysis of process streams for dissolved metal. 

Analysis of process streams, e.g., atomic absorption analysis for detecting heavy metals in a process stream... 

The variety of AES techniques requires careful evaluation for selecting the proper approach to an analytical problem. Table 4 only suggests the various characteristics. More detailed treatment of detection limits must include consideration of spectral interferences (191). AES is the primary technique for metals analysis in ferrous and other alloys geological, environmental, and biological samples water analysis and process streams (192). 

It is obvious that the simpler a method of analysis, the easier it will be to automate. Non-destructive methods which involve a minimum of sample treatment are the most attractive. X-ray fluorescence, for example, has been successfully applied to the continuous monitoring and control of process streams. However, the scope of automated analysis is wide and methods have been designed with a basis in nonspecific properties (pH, conductance, viscosity, density) as well as those characteristic of the che-... 

Flow injection analysis is a fast-developing technique with many potentialities. Particular attractions are the relative simplicity of operation and automation, together with sample throughputs which may exceed 100 per hour. Thus routine monitoring of process streams and pollution control are obvious areas for application. 

The data generated by ELASC on the four routes to radafaxine were supported and confirmed by independent analysis of process waste streams, and are summarized in Table 10.3 and Eigure 10.7. 

Clevett, K. J. Handbook of Process Stream Analysis (Wiley, New York, 1986). 

The composition of process streams can be of interest to guarantee product quality by keeping impurities below specified limits, because of safety and pollution concerns or to make sure that the heating values and other properties of intermediate streams are as they should be. Other reasons for installing process analyzers include reduction of by-products, decrease in analysis time, tightening of specifications, and monitoring of contaminants, toxicants, or pollutants. 

Chemicals must meet certain specifications to be salable. Thus, analysis of process steams must be regularly made to determine their quality. Although there is a trend toward on-line analysis, samples of process streams must still be taken to check instrument performance. Also, there are still many analyses that caimot be made on-line. According to Peters and Timmerhaus [4] and Humphreys [5], the cost of quality control varies from 10 to 20% of operating labor. Use a value of 20% in Table 2.1. 

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