Start-up

Process operations. The third source of process waste we can classify under the general category of process operations. Operations such as start-up and shutdown of continuous processes, product changeover, equipment cleaning for maintenance, tank filling, etc. all produce waste. 

Sources of waste in process operations a. Start-up I shutdown in continuous processes... 

Reactors at nonoptimal conditions produce (additional) unwanted byproducts. Not only might this lead to loss of material through additional byproduct formation, but it also might prevent the recycling of material produced during the start-up. 

In continuous processes, all those sources of process waste associated with start-up and shutdown also apply to product changeover in multiproduct plants. 

Knowing where waste is going is the key to reducing it. When reducing waste from process operations, a steady-state mass balance is not usually comprehensive enough. A balance that takes into account start-up, shutdown, and product changeovers is required. 

If botb reboiler and condenser are integrated with the process, this can make the column difficult to start up and control. However, when the integration is considered more closely, it becomes clear that both the reboiler and condenser do not need td be integrated. Above the pinch the reboiler can be serviced directly from hot utility with the condenser integrated above the pinch. In this case the overall utility consumption will be the same as that shown in Fig. 14.16. Below the pinch the condenser can be serviced directly by cold utility with the reboiler integrated below the pinch. Now tlje overall utility consumption will be the same as that shown in Fig. 14.1c. 

Regarding product characteristics, European specifications were established in 1992. They concern mainly the motor octane number (MON) that limits the olefin content and which should be higher than 89, and the vapor pressure, tied to the C3/C4 ratio which should be less than 1550 mbar at 40°C (ISO 4256). On the other hand, to ensure easy vehicle start-ups, a minimum vapor pressure for winter has been set which is different for each country and depends on climatic conditions. Four classes. A, B, C, and D, are thus defined in Europe with a minimum vapor pressure of 250 mbar, respectively, at -10°C (A), -5 C (B), 0°C (C) and -t-10°C (Z)). France has chosen class A. 

In 1986 when the oil price crashed to 10 a barrel, operators began to look very hard at the requirements for offshore developments and novel slimline, reduced facilities platforms began to be considered. The reduced capital outlay and early production start up capability, coupled with the added flexibility, ensured that all companies now consider subsea systems as an important field development technique. Although the interest and investment in subsea systems increased dramatically, subsea systems still had to compete with the new generation of platforms, which were becoming lighter and cheaper. 

The changes described above also allowed much easier access to the high voltage cable for routine (6-month) owner directed, service operations, and provided better upper and lower x-ray cabinet and control cabinet ventilation. With the exception of the x-ray tubes, all the individual manufactured components, on all four systems are identical. There are very subtle differences in the warm-up/start-up sequence on the x-ray controllers on the newer systems due to model/year and x-ray tube differences. The last three systems were supplied with environmental type key-boards for the image processors and base-mounted , rather than conduit-mounted exterior warning indicators. The first system was subsequently upgraded to include the better keyboard and the external warning appliances/features. 

As I mentioned, USC provided some start-up funds for the Institute. Further development and operation, however, was only possible... 

After Strike wrote the first edition and started up the old web site, a lot of new theories came in. The most promising was a proposition from our founding father of cyber chemistry Eleusis. This was his proposal ... 

Dear readers please take notice Not once has the flask left the stirplate since the formamide and P2P reaction started up to the last point where MDA freebase was liberated. That s pretty damn convenient. Technically, the Leuckart reaction can continue as a one pot synthesis from the last part of P2P cleanup right up to final product. 

Time, Cost, and Equipment Automated chemical kinetic methods of analysis provide a rapid means for analyzing samples, with throughputs ranging from several hundred to several thousand determinations per hour. The initial start-up costs, however, may be fairly high because an automated analysis requires a dedicated instrument designed to meet the specific needs of the analysis. When handled manually, chemical kinetic methods can be accomplished using equipment and instrumentation routinely available in most laboratories. Sample throughput, however, is much lower than with automated methods. 

In late 1997, DSM (Stamicarbons parent company) will start up a new plant utilizing, the next step, a pool reactor (see Figs. 6 and 7). In 1999 this process should be offered for licensing. 

Economic Aspects. In 1994, there were 16 operating hardboard and hardboard siding mills in the United States. Production was 1.535 x (2) in standard hardboard products. These figures do not include the significant quantities of door skin products made, for which production quantities are not tabulated. Production of hardboards has been relatively stable in recent years, considering them as a group. There have been a few new mill closings and a few mill start-ups. In addition, imports of hardboard have also become more common in recent years. 

Conversion of acetaldehyde is typically more than 90% and the selectivity to acetic acid is higher than 95%. Stainless steel must be used in constmcting the plant. This is an estabHshed process and most of the engineering is weU-understood. The problems that exist are related to more extensively automating control of the system, notably at start-up and shutdown, although even these matters have been largely solved. This route is the most rehable of acetic acid processes. 

The modified Reppe process was installed by Rohm and Haas at thek Houston plant in 1948 and later expanded to a capacity of about 182 X 10 kg/yr. Rohm and Haas started up a propylene oxidation plant at the Houston site in late 1976. The combination of attractive economics and improved product purity from the propylene route led to a shutdown of the acetylene-based route within a year. 

Because of projected nylon-6,6 growth of 4—10% (167) per year in the Far East, several companies have announced plans for that area. A Rhc ne-Poulenc/Oriental Chemical Industry joint venture (Kofran) announced a 1991 startup for a 50,000-t/yr plant in Onsan, South Korea (168,169). Asahi announced plans for a 15,000-t/yr expansion of adipic acid capacity at their Nobeoka complex in late 1989, accompanied by a 60,000-t/yr cyclohexanol plant at Mizushima based on their new cyclohexene hydration technology (170). In early 1990 the Du Pont Company announced plans for a major nylon-6,6 complex for Singapore, including a 90,000-t/yr adipic acid plant due to start up in 1993 (167). Plans or negotiations for other adipic acid capacity in the area include Formosa Plastics (Taiwan) (171) and BASF-Hyundai Petrochemical (South Korea) (167). Adipic acid is a truly worldwide... 

The KDF filter was first tested in prototype on a coal mine in northern Germany. It was installed in parallel with existing vacuum filters and it produced filter cakes consistendy lower in moisture content by 5 to 7% than the vacuum filters. Two production models have been installed and operated on a coal mine in Belgium. The filter is controlled by a specially developed computer system this consists of two computers, one monitoring the function of the filter and all of the detection devices installed, and the other controlling the filtration process. The system allows optimization of the performance, automatic start-up or shut-down, and can be integrated into the control system of the whole coal washing plant. 

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