Alternative Design

The basic seed processing plant design is based on 70% removal of the sulfur contained in the coal used (Montana Rosebud), which satisfies NSPS requirements. Virtually complete sulfur removal appears to be feasible and can be considered as a design alternative to minimize potential corrosion problems related to sulfur in the gas. The estimated reduction in plant performance for complete removal is on the order of 1/4 percentage point. The size of the seed processing plant would have to be increased by roughly 40% but the corresponding additional cost appears tolerable. The constmction time for the 500 MW plant is estimated to be ca five years. 

FIG. 17-43 Some commercial cyclone design alternatives, (Couttesy ofPSRI, Chicago.)... 

A number of design alternatives should be considered when milling materials that are combustible or are temperature sensitive, such as... 

Consider Inherently Safer Design alternatives (e.g., to withstand maximum upset conditions—temperature, pressure, flow)... 

A variation of the two-shaft gas turbine is the aircraft derivative machine. The gas generator is an aircraft jet engine or an adaptation thereof. The power turbine may be of a custom design. Alternately, aircraft based designs may be used. They are covered in API Standard 616 [12]. 

Modeling of Chemioal Kinetios and Reaotor Design Alternatively, the vent area ean be expressed as ... 

Design alternative 1 is inherently safer because the pressure sensor provides continuous feedback to the operator. The operator has some confidence that the pressure sensor is working (although not complete... 

Finally, in considering inherently safer design alternatives, it is essential to remember that there are often, perhaps always, conflicting... 

Design alternatives should include inherently safer reviews. Possible methodologies are presented in Chapter 7. 

Manzer, L. E. (1994). Chemistry and Catalysis. by Design Alternative Synthetic Design for Pollution Prevention, ed. P. T. Anastas, and C. A. Farris, 144-54. Washington, D. C. American Chemical Society. 

Dye, S.R. and Ng, K.M., 1995. Bypassing eutectics with extractive crystallization design alternatives and tradeoffs. American Institute of Chemical Engineers Journal, 41, 1456. 

The numbering of the quinoxaline ring system is as shown, the 2 and 3 positions are designated alternatively a positions. 

A first obvious consequence of such considerations is that we should not only look at the costs of the product from an economic point of view, but that we must consider the costs of the production process in a broader sense. We must take into account the raw materials used, the amount of energy invested and the possibility to design alternatives, more environmentally friendly processes. In other words, we should not only look at the desired product, but we must consider the total life cycle of the product The design of a production process taking into account these aspects is often referred to as integral life cycle management. 

This interplay of the many variables is extremely complex and involves a matrix of the many variables. As an example in the molding simulation TMconcept system programmed Molding Cost Optimization (MCO) of Plastics Computer Inc., Dallas, TX, there are well over 300 variables. It is not reasonable to expect a person using manual methods to calculate these complex interactions even if molding only a modest shaped product without omissions or errors. Computerized process simulation is a practical tool to monitor the influence of design alternatives on the processability of the product and to select molding conditions that ensure the required product quality (3). 

Usually, experience of the past is used as the basis of failure scenarios, whereas one should look at a process each time again as if all unexpected events could occur. One has to keep in mind that accidents are often due to the highly unlikely coincidence or complex casual chains that seem improbable. It is necessary to examine all failure modes for all possible design alternatives in order to decrease the probability of an incident. 

Preliminary (approximate) estimates, accuracy typically 30 per cent, which are used in initial feasibility studies and to make coarse choices between design alternatives. They are based on limited cost data and design detail. 

The primary purpose of the HELP model is to provide water balance data with which to compare design alternatives for conventional barrier-type covers installed on landfills with bottom liners. It provides a tool for both designers and permit writers and is applicable to open, partially closed, or fully closed sites. 

As stated previously, the source of capital is often not known, and hence it is not known whether Equation 2.7 is appropriate to represent the cost of capital. Equation 2.7 is, strictly speaking, only appropriate if the money for capital expenditure is to be borrowed over a fixed period at a fixed rate of interest. Moreover, if Equation 2.7 is accepted, then the number of years over which the capital is to be annualized is known, as is the rate of interest. However, the most important thing is that, even if the source of capital is not known, and uncertain assumptions are necessary, Equation 2.7 provides a common basis for the comparison of competing projects and design alternatives within a project. 

Shonnard DR, Hiew DS (2000) Comparative environmental assessments of VOC recovery and recycle design alternatives for a gaseous waste stream. Environ Sci Technol 34(24) 5222-5228... 

In order to design alternative therapeutic strategies and to identify variances that specify the SCA patient population who will benefit from a safe and effective therapy, the present strategies of pharmacogenomics will involve either a targeted can-... 

To implement inherent safety in practice, a method to estimate the inherent safety of different design alternatives is needed. Methods such as Dow and Mond Indices are commonly used in chemical industry, but their point is mostly in fire and explosion hazards. They also often need detailed information on the... 

This problem, taken from Floudas (1995), involves the manufacture of a chemical C in process 1 that uses raw material B (see Figure E9.3a). B can either be purchased or manufactured via two processes, 2 or 3, both of which use chemical A as a raw material. Data and specifications for this example problem, involving several nonlinear input-output relations (mass balances), are shown in Table E9.3A. We want to determine which processes to use and their production levels in order to maximize profit. The processes represent design alternatives that have not yet been built. Their fixed costs include amortized design and construction costs over their anticipated lifetime, which are incurred only if the process is used. 

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