Plant concepts

A commercial combustion turbine with the provision to inject, at any point upstream of the combustor, the externally supplied humidified and preheated supplementary compressed air. Engineering and mechanical aspects of the air injection for the compressed air injection plant concepts are similar to the steam injection for the power augmentation, which has accumulated significant operating experience. 

Recently, microstructured reactors have stepped into chemical production [4] and thus microreactor process and plant design, including economic incentives, is the issue at this time. For this purpose, large-capacity microstructured apparatus is needed ( micro inside, fist- to shoebox size outside ) and plant concepts have to be proposed which include all process steps. 

Rinard dedicated his research to a detailed analysis of methodological aspects of a micro-reactor plant concept which he also termed mini-plant production [85] (see also [4, 9, 10] for a commented, short description). Important criteria in this concept are JIT (Just-in-time) production, zero holdup, inherent safety, modularity and the KISS (keep it simple, stupid) principle. Based on this conceptual definition, Rinard describes different phases in plant development. Essential for his entire work is the pragmatic way of finding process solutions, truly of hybrid character ]149] (miniaturization only where really needed). Recent investigations are concerned with the scalability of hybrid micro-reactor plants and the limits thereof ]149], Expliddy he recommends jointly using micro- and meso-scale components. 

Hessel, V., Lowe, H., Micro chemical engineering components - plant concepts -user acceptance Part III, Chem. Eng. Technol. 26, 5 (2003) 531-544. 

Hessel, V., Hardt, S., Lowe, H., Chemical processing with microdevices device/plant concepts, selected applications and state of scientific/comvnercial implementation, in Proceedings of the 6th Italian Conference on Chemical and Process Engineering, ICheaP-6, 8-11 )une 2003, Pisa, Chem. Engin. Trans. 3,... 

The conceptual design and operation were stated to be based on experiences AEC has accumulated in its operations. 7 In fact the design was based on the ORNL pilot plant concept incorporated in the Idaho Chemical Processing Plant which cost about 20 million TOE was based on experiences at Hanford and SRP in plants that cost about 100 million. The TOE for the ICPP was not 80%, but 3%8,and there were major safety deficiencies. 

This facility design concept was not considered in White House reviews of reprocessing during the Ford and Carter Administrations, nor as an option for support by President Reagan, who had been elected on a platform to support reprocessing of commercial spent firel. The ERDA and the DOE had reassigned responsibilities for commercial fuel cycle to its Division of Reactor Development (later Office of Nuclear Energy) which supported pilot plant concepts of its national laboratories and rejected concepts based on successful experience and lessons learned from that experience. 

Axelrod, L., Daze, R.E., Wickham, H.P. Practical Aspects of the Large Plant Concept, paper presented at the 60th Annual Meeting of AIChE., New York, Nov. 28, 1967. 

Because of the high standards for the avoidance of leakage and reliability, up to now the application of the pipeless plant concept is limited to plants with moderate processing conditions (low pressures and temperatures, in most cases atmospheric pressure) [2],... 

Comparison ofthe Plant Concepts To be able to compare the pipeless plant concept with the existing multipurpose batch plant, a reference plant was modelled using PPSiM. In the existing plant three conventional batch mixers work in a shifted parallel fashion. The three batch mixers were modelled by three stations and equipped with all technical functions necessary for the production of all recipes. Therefore each batch could be processed at one of the stations and the vessel transfers were limited to the transportation of empty or loaded vessels. All the other parameters of the model, e.g., charging mass flows, the durations of vessel cleanings and the recipes remained unchanged. 

Table 3.4 lists the production times and the processing times of the evaluated scenarios. Figure 3.6 compares the processing times of both plant concepts. Scenario G2 in Table 3.4 is identical to configuration 8 in Table 3.2. 

The comparison of the two plant concepts shows that the pipeless plant concept leads to smaller production and processing times at batch sizes of200 and 500 kg. This advantage decreases towards smaller batch sizes. 

Assessment of the Plant Concepts The economic comparison of the pipeless plant developed in this study with the existing multipurpose batch plant resulted only... 

The pipeless plant concept leads to 20% shorter processing times for batch sizes between 200 and 500 kg, what clearly reduces the manufacturing costs of the products. By the distribution of the technical functions on several stations, the transport of the intermediate products in mobile vessels and the cleaning of the vessels in separate cleaning stations, the utilization of the stations rises and in parallel the productivity of the plant is increased. 

Further advantages result from the immanent flexibility of the pipeless plant concept. By the possibility of storage of intermediate products during the production, urgent orders with a higher priority can be preferred or inserted into the production plan. 

For the investigation of logistic questions or for the design of pipeless plants, like in the presented use-case, PPSiM offers a suitable solution. The comparison between the two plant concepts showed that the developed pipeless plant configuration leads to 20 % shorter processing times for similar investments, due to the higher utilization of the plant equipment. 

Improved next-generation ODC with a catalyst based on rhodium [6] promises an even more simplified plant concept. This is due to the fact that this type of ODC does not require polarisation during shut-down as an inert cathode is no longer necessary. The plant can simply be put at stand-by where the anode side, as well as the HC1 circuit, remains pressurised under chlorine saturation. Therefore, re-starting the operation is very simple and the chlorine supply is derived directly from the electrolysis and liquid chlorine evaporation is no longer necessary. Instead, with a liquid chlorine buffer, the system can be re-started from the hydrochloric acid storage tank. 

The plant concept for co-production of hydrogen and electricity is applicable to a very broad range of fossil fuels and also biomass without paying tributes to climate change. At the same time energy supply security is improved, as a result of the diversification of (fossil) feedstock options. 

This natural gas fuel cell power system is based on a pressurized TSOFC combined with a combustion turbine developed by Siemens Westinghouse (52). Most TSOFC power plant concepts developed to date have been based on atmospheric operation. However, as shown in... 

T.J. George, K.D Lyons, and R. James m, "Multistaged Oxide Fuel Cell Power Plant Concept," May 1998. 

Netherlands - fuel cell research activities include SOFC and PEM, including demonstrating local CHP generation and the virtual power plant concept, which is testing some 30 PEM systems in the field. 

The degree and the extent of segregation have a direct impact on the investment and the operating costs. A helpful overview of different multipurpose plant concepts can be found in the text by Rauch [5],... 

Plants to produce low-sulfur fuels from coal, oil shale, tar sands or heavy oil frequently are conceived to use the Claus process to produce byproduct sulfur. Often the plant concept imposes unacceptable technical burdens on the Claus section. This paper points out some of the problems, and some solutions. In particular, the paper discusses a Claus type process recently developed with special application to coal and oil gasification plants. 

A plant contains all production units required to produce a certain intermediate or finished product. The relationship between a site s plants varies between two extremes. At integrated sites (Verbundstandorte) the plants cover certain steps of the overall production process and are closely linked by material flows. This can be seen as a "plant within a plant" concept based on a process focus. Integrated sites are especially common in production of commodity chemicals. For example, the new integrated site built by BASF in Nanjing, China, consists of a steam cracker producing among others ethylene and propylene. Nine other plants further process the substances. The overall investment to build the site was U.S. 2.9 billion.10... 

There is no doubt that the ultimate development of process intensification leads to the novel field of microreaction technology (Figure 1) (7-9). Because of the small characteristic dimensions of microreaction devices, mass and heat transfer processes can be strongly enhanced, and, consequently, initial and boundary conditions as well as residence times can be precisely adjusted for optimizing yield and selectivity. Microreaction devices are evidently superior, due to their short response time, which simplifies the control of operation. In connection with the extremely small material holdup, nearly inherently safe plant concepts can be realized. Moreover, microreaction technology offers access to advanced approaches in plant design, like the concept of numbering-up instead of scale-up and, in particular, the possibility to utilize novel process routes not accessible with macroscopic devices. 

The layout of the new plant concept with the integrated and intensified pool reactor now has a height of 18 m, a height reduction by a factor of 3. Also, the number of units has been decreased. This is illustrated in Figure 11, in which the development of the urea process is depicted. In this figure it can be seen that even an old proven bulk chemical process can be intensified, resulting in a much more compact and economical plant. 

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