Flowsheet development

Figure 1-36. Process engineering costs (1975), based on process engineering charged at 14 per manhour. Chemical plant engineering operations, includes flowsheet development and drafting, material and heat balances, equipment designs, ratings, checking, and bid reviews and selection of equipment. By permission, E. E. Ludwig [7].

T. K. Mukherjee and C. K. Gupta, Flowsheets Development for Recovery of Nonferrous Metal values from Secondary Resources by Solvent Extraction, Proceed, of a Symposium - Emerging Separation Technologies for Metals II Sponsored by the Engineers Foundation Conference and the National Science Foundation held at Kona, Hawaii, June 16-21,1996. 

Flotation flowsheet developed for the treatment of gold-containing mercury-antimony... 

The main task in flowsheet development is the desliming size to reduce niobium losses in the slime fraction. The generalized flowsheet used in this case study is shown in Figure 22.5. 

The flowsheet (Figure 25.18) shows the final flowsheet developed for the beneficiation of the Guadalajara ore. This flowsheet consists of two flotation circuits (a) gangue prefloat circuit, where the apatite and calcite are recovered, and (b) titanium flotation circuit, where... 

The flowsheet developed for beneficiation of the White Mountain titanium ore consist of two distinct circuits (a) grinding, sizing and gravity preconcentration of the ore, and (b) rutile flotation from the gravity concentrate. This flowsheet includes gravity preconcentrate and flotation as shown in Figure 25.19. 

Figure 25.18 Flowsheet developed for beneficiation of the Guadalajara (Mexico) hard rock rutile ilmenite ore.

The second part deals with applications of solvent extraction in industry, and begins with a general chapter (Chapter 7) that involves both equipment, flowsheet development, economic factors, and environmental aspects. Chapter 8 is concerned with fundamental engineering concepts for multistage extraction. Chapter 9 describes contactor design. It is followed by the industrial extraction of organic and biochemical compounds for purification and pharmaceutical uses (Chapter 10), recovery of metals for industrial production (Chapter 11), applications in the nuclear fuel cycle (Chapter 12), and recycling or waste treatment (Chapter 14). Analytical applications are briefly summarized in Chapter 13. The last chapters, Chapters 15 and 16, describe some newer developments in which the principle of solvent extraction has or may come into use, and theoretical developments. 

Law, J.D., Herbst, R.S., Todd, T.A. et al. 2001. The universal solvent extraction (UNEX) process. II. Flowsheet development and demonstration of the UREX process for the separation of cesium, strontium, and actinides from actual acidic radioactive waste. Solvent Extr. IonExch. 19 (1) 23-36. 

The flowsheet of the UREX process, developed in the United States, includes the following extraction cycles (1) separation of uranium and technetium, (2) separation of plutonium, (3) separation of cesium and strontium, (4) separation of MAs and Rare Earth Elements (REE), and (5) group separation of MA from REE metals.9,10 Flowsheet development in Europe11 includes a modified PUREX process and, after that, the DIAMEX process for separation of MAs and lanthanides, the SANEX process for separation of MAs from lanthanides, and a special cycle for Am/Cm separation. Cesium and strontium will be in the raffinate of the DIAMEX process, and this raffinate will be vitrified, or cesium can be preliminarily extracted.12... 

The next section will reflect on common conceptual process design practices for overall flowsheet development. The remainder of this chapter reviews recent developments in process synthesis methods for reaction and separation systems that systematically guide the design decision-making process toward novel and improved designs. 

The flowsheet synthesis of continuous chemical-like process can be performed following a systematic strategy known as the hierarchical approach. The procedure, initially proposed by Jim Douglas and coworkers in the decade 1980-90 [1, 2], describes the conceptual design process as a logical sequence of analysis and synthesis steps grouped in levels. Each level involves a flowsheet development mechanism based on design decisions. The result is not a unique solution but a collection of alternative flowsheets from which an evaluation procedure eliminates the less attractive ones. 

EPI/0 is useful for assessing the feasibility of alternative chemistries and sources of raw materials before undertaking a more detailed flowsheet development. Clearly, the economic potential should be largely positive to accept further reductions when the capital and operation costs are taken into account. 

An economic analysis was carried out by Knoche and Funk (4) based upon a flowsheet developed by Westinghouse. This analysis indicated a projected hydrogen cost of about 6.50/106 Btu based upon the following fundamental assumptions ... 

Treatment of Waste Solutions containing Americium. The process flowsheets developed to treat Masurca waste and the solution from recycling of Pu02 scrap are presented in Figure 6. Treatment of the Masurca whste is complex and requires the following steps. 

Mclsaac, L. D., Baker, J. D., Krupa, J. F., Meikrantz, D. H., and Schroeder, N. C., "Flowsheet Development Work at the Idaho Chemical Processing Plant for the Partitioning of Actinides from Acidic Nuclear Waste," Actinide Separations Symposium, ACS Pacific Chemical Conference, Honolulu,... 

Flowsheet Development Work at the Idaho Chemical Processing Plant for the Partitioning of Actinides from Acidic Nuclear Waste... 

Flowsheet development involves the selection of the equipment and the interconnects that integrate the equipment into a working system. Two approaches are used for the development of the flowsheet mathematically based programming and the use of heuristics and evolutionary development. 

At each level of the Hierarchical Approach the feasibility of design alternatives are evaluated by means of an Economic Potential (EP). This index is a measure of profitability representing the difference between earnings and expenses on yearly basis. EP must be high enough to accept further reduction at the other levels of flowsheet development. If EP is not positive and high enough, the analysis stops. It is worthy to note that the raw material costs dominate the operation costs in chemical process industries by more than 60%, particularly in commodities. 

The structure of the separations is determined by the composition and the thermodynamic properties of the mixture leaving the reactor. The first phase-split is essential, because it enables the decomposition of the separation problem in subproblems or subsystems, where specific systematic procedures can be applied. Therefore, we will start the flowsheet development by examining this key topic. 

A central issue in process design is the selection of the best reactor that could meet the process requirements before to start the flowsheet development. An ideal reactor configuration should conciliate process operability with productivity requirements. In this respect we may mention ... 

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