Existing Processes

If compounds already react very fast with ozone, the addition of hydrogen peroxide is nearly ineffective, which was shown by Brunet et al. (1984) in the case of benzaldehyde and phthalic acid. The functional groups on the aromatic ring are relatively reactive towards molecular ozone. The advantage of this process lies in the removal of compounds relatively non-reactive with ozone. It was shown that the oxidation of oxalic acid, which is often an end product in the case of molecular ozone reactions, was significantly accelerated with the addition of hydrogen peroxide. 

An optimum dose ratio of H202/03 has often been shown to be in a molar range of 0.5-1 depending on the presence of promoters and scavengers. Peroxide itself can act as a scavenger as well as an initiator, so searching for the optimum dose ratio is important. Enhancement of ozone mass transfer over that during ozonation alone can be expected in many cases. 

Because of the stronger photolysis of ozone compared to hydrogen peroxide in combination with UV radiation (e254nm = 3 300 M l cm-1 compared to 254 nm = 19 M 1 cm-1 for 

H202) the oxidation potential is higher than in the combination hydrogen peroxide/UV radiation (see below). 

Prengle et al. (1975) were the first to see the commercial potential of the 0-,/UV system in waste water. They showed that this combination enhances the oxidation of complexed cyanides, chlorinated solvents, pesticides and lumped parameters like COD and BOD (cited by Glaze et al., 1987). 

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The safety review report is distributed to the committee which meets to work its way through the report, section by section, discussing safety concerns and potential improvements to the process or procedure. An individual must be designated to take minutes at the meeting and record suggested modifications. If the review concerns an existing process, the committee should perform a site visit to examine the actual equipment. 

The safety review technique is also usehil for small laboratory operations and small changes in existing processes. In these cases, the committee often consists of two or three people and any changes are often less formally recommended. 

Documentation of experimental method so that work can be reproduced at a later time Appropriate data handling statistical methods conclusions based on fact, supportable by data Define and execute critical experiments to prove or disprove hypothesis Mechanistic or fundamental interpretation of data preferred Communication of Conclusions to Incorporate Technical Learning in Organization Experimental W rk Done in Support of New or Existing Processes Should be Captured in Process Models... 

The fixed capital estimate depends on the definition of the plant. A grass-roots plant is a complete faciUty at a new location, including all utihties, services, storage faciUties, land, and improvements. If a process plant is located at an existing processing complex, it can usually share some of these auxihary faciUties. A battery-limits plant is defined as the process faciUty itself, so that the auxiUaries, off-site, and land-related items are excluded from the fixed capital estimation. However, a battery-limits plant maybe assigned allocated capital charges for the share of common utihty and service faciUties used by the plant. 

When to Scrap an Existing Process Let us suppose that a company invests 50,000 in a manufacturing process that has positive net annual flows (after tax) Acp of 10,000 in each year. During the third year of operation, an alternative process becomes available. The new process would require an investment of 40,000 but would have positive net annual cash flows (after tax) of 20,000 in each year. The cost of capital is 10 percent, and it is estimated that a market will exist for the product for at least 6 more years. Should the company continue with the existing process (project H), or should it scrap project H and adopt the new process (project 1) ... 

Process. synthesis. Concept development, construction of flowsheets for new processes, and redesign or modification of existing process flowsheets. 

Exploration for an acceptable or optimum design of a new reaction process may need to consider reactor types, several catalysts, specifications of feed and product, operating conditions, and economic evaluations. Modifications to an existing process hkewise may need to consider many cases. These efforts can oe eased by commercial kinetics services. A typical one can handle up to 20 reactions in CSTRs or... 

Reactive Hazard Review Reactive hazards should be evaluated using reviews on all new processes and on all existing processes on a periodic basis. There is no substitute for experience, good judgment, and good data in evaluating potential hazards. Reviews should include ... 

Process-specific training prior to each compaign for existing processes... 

A HAZOP is used to question every part of a process to discover what deviations from the intention of the design can occur and what their causes and consequences may be. This is done systematically by applying suitable guidewords. This is a systematic detailed review technique, for both batch and continuous plants, which can be applied to new or existing processes to identify hazards. 

Any pre-existing process hazards analysis from the pilot development or other tolling efforts... 

Does a new or existing process that is being run simultaneously or in series with the toll in question present the new hazard ... 

The hazard identification step of the QRA typically requires the greatest involvement of plant personnel. For an existing process, only plant personnel know the status of process equipment and the current operating and maintenance practices. Excluding those personnel from the hazard identification step increases the chance of overlooking important potential hazards. For accurate results, the QRA team must have access to this information. 

A preliminary estimate is useful for the linear velocity to be used on the catalyst under study. The linear flow is known for an existing process. For a new process, it can be estimated from flow used in similar processes. An estimate can also be developed for the minimum flow to avoid gradients from calculations (to be presented in Appendix C.)... 

An improved catalyst for an existing process, where variations in experimental condition are possible only in a limited range see section 5.2. 

Control of stationary sources of air pollution requires the application of either the control concepts mentioned in Chapter 28 of the control devices mentioned in Chapter 29. In some cases, more than one system or device must be used to achieve satisfactory control. The three general methods of control are (1) process change to a less polluting process or to a lowered emission from the existing process through modification of the operation,... 

Understand existing operations of similar process units before embarking on a new design. Lieberman gives the following ways to become familiar with an existing process ... 

Because fuel costs are high, the search is on for processes with higher thermal efficiency and for ways to improve efficiencies of existing processes. One process being emphasized for its high efficiency is the gas turbine combined cycle. The gas turbine exhaust heat makes steam in a waste heat boiler. The steam drives turbines, often used as lielper turbines. References 1, 2, and 3 treat this subject and mention alternate equipment hookups, some in conjunction with coal gasification plants. 

Calculate the annual operating costs for the existing process that needs waste treatment, and estimate how these costs would be altered by the introduction of waste-reduction options. Tabulate and compare the process and waste-treatment operating costs for both the existing and proposed waste-management options. If there are any monetary benefits (such as recycled or reused materials or wastes), then these should be subtracted from the total process or waste-treatment costs as appropriate. The expanded cost-analysis scheme discussed in Chapter 8 is appropriate to include at this point in the process. 

Chemical Flowsheet Basic unit operation selection with flow rates, conversion factors, temperatures, pressures, solvents and catalyst selection Process synthesis route Laboratory and pilot scale trials Knowledge of existing processes... 

Creative thinking is important not only in new process development, but also in continually reviewing and reevaluating existing processes for opportunities to make the process inherently safer. Many of the tools and techniques discussed in Section 4.2, on Research, are useful in the process development stage as well. It is appropriate to revisit the basic chemistry to study alternate options. 

Implementing an inherent safety review process is one mechanism companies can use to institutionalize inherent safety. The review process should integrate well with company systems for process safety management, new product development, and project execution. Safety, health, and environmental considerations in the new product or process development effort can be strengthened via the introduction of the inherent safety review. Companies may also build inherently safer design concepts into their existing process safety management system and process hazard reviews. 

For an existing process plant, the designer has the opportunity to take measurements of the fume or plume flow rates in the field. There are two basic approaches which can be adopted. For the first approach, the fume source can be totally enclosed, and a temporary duct and fan system installed to capture the contaminant. For this approach, standard techniques can be used to measure gas flow rates, gas compositions, gas temperatures, and fume loadings. From the collected fume samples, the physical and chemical characteristics can be established using standard techniques. For most applications, this approach is not practical and not very cost effec tive. For the second approach, one of three field measurement techniques, described next, can be used to evaluate plume flow rates and source heat fl uxes. 

Having designed the additional processes, you need to examine existing processes and establish the extent to which they are compliant with the relevant requirements of ISO/TS 16949. Remember that the requirements are a framework. They are not exhaustive. Your processes should possess characteristics that are compliant but are likely to possess many other characteristics that are not addressed by the requirements. 

The next stage is to design the processes that have been identified. In many cases, existing processes may well satisfy the need but process approval may be required if the tolerance on product characteristics is much less than the currently demonstrated process capability. Process design is a subject outside the scope of ISO 9001 but is covered by clause 4.2.4.9 of ISO/TS 16949 and hence addressed in Part 2 Chapter 2. 

In process mapping you are interested in the way the process flows through the organization. Using the information gathered in your interviews you should be able to overlay the process onto an organization chart. This is illustrated in Exhibit 3-4. In Exhibit 3-4 several problems with the existing process are immediately obvious ... 

Flow charts may be developed through interviews or by assembling a group familiar with the existing processes. A facilitator helps the team identify all the process steps and builds up a representation of the overall process on a board using removable sticky notes. The resulting flow chart, Exhibit 3-5, has a more familiar look than that in Exhibit 3-4. 

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