Total Plant Performance Research Articles

Towards a generic optimal co-design of hardware architecture and control configuration for interacting subsystems

In plants consisting of multiple interacting subsystems, the decision on how to optimally select and place actuators and sensors and the accompanying question on how to control the overall plant is a challenging task. Since there is no theoretical framework describing the impact of sensor and actuator placement on performance, an optimization method exploring the possible configurations is introduced in this paper to find a trade-off between implementation cost and achievable performance.Moreover, a novel model-based procedure is presented to simultaneously co-design the optimal number, type and location of actuators and sensors and to determine the corresponding optimal control architecture and accompanying control parameters. This paper adds the optimization of the control architecture to the current state-of-the-art. As an optimization output, a Pareto front is presented, providing insights on the optimal total plant performance related to the hardware and control design implementation cost.The proposed algorithm is not focused on one particular application or a specific optimization problem, but is instead a generally applicable method and can be applied to a wide range of applications (e.g., mechatronic, electrical, thermal). In this paper, the co-design approach is validated on a mechanical setup.

Total plant performance evaluation based on big data: Visualization analysis of TE process

Abstract The performance evaluation of the process industry, which has been a popular topic nowadays, can not only find the weakness and verify the resilience and reliability of the process, but also provide some suggestions to improve the process benefits and efficiency. Nevertheless, the performance assessment principally concentrates upon some parts of the entire system at present, for example the controller assessment. Although some researches focus on the whole process, they aim at discovering the relationships between profit, society, policies and so forth, instead of relations between overall performance and some manipulated variables, that is, the total plant performance. According to the big data of different performance statuses, this paper proposes a hierarchical framework to select some structured logic rules from monitored variables to estimate the current state of the process. The variables related to safety and profits are regarded as key factors to performance evaluation. To better monitor the process state and observe the performance variation trend of the process, a classification-visualization method based on kernel principal component analysis (KPCA) and self-organizing map (SOM) is established. The dimensions of big data produced by the process are first reduced by KPCA and then the processed data will be mapped into a two-dimensional grid chart by SOM to evaluate the performance status. The monitoring method is applied to the Tennessee Eastman process. Monitoring results indicate that off-line and on-line performance status can be well detected in a two-dimensional diagram.

System modeling of exergy recuperated IGCC system with pre- and post-combustion CO2 capture

This paper describes a novel advanced integrated gasification combined cycle (A-IGCC) for heat integration technology with carbon dioxide (CO2) capture. The feature of this system is an exergy recuperation in which the exhaust heat from the gas turbine and the steam are used as gasifying agents, providing higher cold gas efficiency. A-IGCC can achieve higher plant thermal efficiency with much less energy/exergy loss compared to a conventional IGCC. Two CO2 capture options, (i) pre-combustion by a mixture of dimethyl ethers of polyethylene glycol (DEPG) and (ii) post-combustion by monoethanolamine (MEA), were assessed to compare the total plant performance and necessary technologies for future implementation. A-IGCC maintained a higher plant performance than IGCC, delivering sufficient energy in the gasifier for the autothermal reaction. A higher efficiency was obtained in IGCC with pre-combustion capture, with a thermal efficiency of 33.2% compared to 43% without capture. In A-IGCC, however, the higher efficiency was obtained with post-combustion capture, with a thermal efficiency of 38.5% compared to 50.6% without capture. Adding a CO2 removal unit with 81 mol% CO2 absorption imposed the plant efficiency loss of 9.9–15.2%. The surplus heat at lower temperature was left unused when pre-combustion capture was used for the A-IGCC plant model, which resulted in a large reduction in plant efficiency.

The Impact of Water on Energy Conservation

ABSTRACT This article shows how carpet dyeing plants at Shaw Industries have achieved significant energy reductions as an extension of water conservation and water heating reductions in 2007–2008. Those savings came from the following: 1. Water conservation—both water reuse and reductions in quantity 2. Rinse water temperature reductions 3. Waste-water heat recovery The impact of these is discussed, and the overall plant performance is presented. Savings for both total water and total energy have exceeded 20% in some plants. The article includes a process description for the continuous dye line and typical energy and water inputs for each step of the process. Specific changes are itemized, then the revised energy/water inputs for the line are presented. Finally, one plant's total energy per unit of production over the course of two years shows the impact of the improvements on total plant performance.

Interplant root competition leads to an overcrowding effect in maize

We conducted an experiment with two maize hybrids (Zea mays L.) to examine the effect of interplant root competition on root growth and to evaluate the impact to total plant performance. Two maize hybrids (Jinhai 5 and Denghai 3719) were grown either with no root competition in their own plot (owners) or as individuals sharing twice the space and nutrients (sharers). Plants were sampled every other week after pollination to track changes in root and shoot biomass. The carbohydrate allocation was smaller in the roots of sharers compared with owners at the pro-phase of grain filling and shoot accumulation was slightly accelerated during this period. However, at the lag phase, the accumulation rate in the shoots of individual plants was distinctly lower than in owners, as a result of earlier root senescence. Overall, shoot mass was reduced by 8% in sharers of both hybrids, while they showed a similar root to shoot ratio compared with the owners. Although the “sharing” treatment was confounded by larger soil spaces, the effects of larger soil volume and interplant root competition were different, and demonstrate that interplant root competition has an inhibitory effect on roots. Maize plants displayed an overcrowding effect (or an escape strategy) by allocating more carbohydrate to the shoots at the expense of the roots when faced with interplant root competition.Key words: Overcrowding effect, interplant root competition, maize (zea mays L.), root discrimination

Selection for seed yield in Andean intra-gene pool and Andean × Middle American inter-gene pool populations of common bean

Yields of large-seeded Andean (A) common bean (Phaseolus vulgaris L.) cultivars of Chile and Nueva Granada races are 40 to 60% lower compared to their Middle American (M) counterparts of small-seeded Mesoamerica and medium-seeded Durango races. Our objective was to use the concept of congruity backcrossing between Andean x Middle American inter-gene pool [AM 11833 = A 483 (A)///// A 686 (M) //// PVA 800A(A)/// ‘Carioca’ (M)// Carioca (M)/ G 19833 (A)] and between races within Andean gene pool [i.e., intra-gene pool Andean, AA 11834 = A483 (A)//// ‘Cardinal’(A) /// ‘Blanco Espanol’(A) // BlancoEspanol (A) / ‘Taylor’ (A)] to compare selection for seed yield improvement of large-seeded Andean beans. Seven hundred sixty seven F2-derived F3 (F2:3) families were produced for each population. Visual appraisal for total plant performance, combined with seed yield from non-replicated plots was used for selection of 551 families in F2:3, 182 families in F2:4, and 91 families in F2:5 in each population. Eight hundred twenty three F5:6 lines were developed from the 91 F2:5 families in each population. Visual selection, combined with seed yield in non-replicated plots was again used to select 294 lines in F5:6 in each population. Similarly, 44 highest yielding F5:7 lines were selected in AM 11833 and 39 F5:7 lines in AA 11834. Thus, single plant selections were made in the F2 and F5, and plants within each plot were harvested in bulk in F3, F4, F6, and F7. Thirty nine F5:8 lines from AA 11834 and 44 lines from AM 11833, parents, and checks were evaluated at Popayan and Quilichao, Colombia in 1998 and 1999. Selected lines in both populations, on average, out-yielded the mean of their large-seeded Andean parents. Mean yield of the lines selected from AM 11833 was 50% higher than AA 11834 lines. Twelve F5:8 lines out-yielded the highest yielding Andean parents G 19833 and A 483 in AM 11833, whereas only one line yielded significantly higher (p < 0.05) than the highest yielding parent A 483 in AA 11834. However, none of selected lines out-yielded small-seeded Middle American parents used in AM 11833 (A 686 and ‘Carioca’). The mean 100 seed-weight of AA 11834 was 36 g compared to 28 G for AM 11833 F5:8 lines. Selected lines had similar days to maturity as parents in AM 11833, and matured 3 d later in AA11834. Correlation coefficients between yield and 100 seed-weight were negative in both populations. Yield and days to maturity were positively correlated in AA 11834.

Effective desliming of froth flotation cell feed at Elk Run Coal Co.

This paper focuses on the −½ mm cleaning at Elk Run Coal. The original circuitry incorporated desliming cyclones. Problems with slimes entrainment in the cyclone underflow (froth cell feed) resulted in poor froth cell selectivity. Laboratory test work led to the installation of high frequency desliming screens. Consequently, great improvement in cell performance was brought about by enhanced desliming with the ability to use split flotation. The modifications resulted in significant improvement in total plant performance and overall yield while maintaining clean coal quality.

Plant responses to high temperatures.

Research has shown that there are wide diversities in heat tolerance among crops, and that differences occur not only between crop species, but also among genotypes within the species. Sufficient variability occurs to select for genotypes with high heat tolerance. Under field conditions, drought stress often accompanies heat stress, and there are usually interactions of plant response to these two stresses. Consequently, heat and drought resistance are usually considered together in field response, but each mechanism must be considered separately in order fully to understand the response. An example is given in which sorghum is regarded as having greater stress resistance than corn from field performance. However, results showed that cellular tolerance to high temperatures was higher in corn than in sorghum and higher in pearl millet than in corn. This was true not only of cellular membrane stability, but also of isolated chloroplast activity and photosynthesis of intact leaves under controlled conditions. Results also showed that the drought-avoidance mechanisms were inadequate in corn as compared to sorghum; therefore, corn-leaf tissue may be more frequently exposed to high temperatures owing to decreased evaporative cooling, and the critical limits of high temperature and desiccation tolerance exceeded, resulting in leaf “firing,” even though cellular tolerance is greater than that of sorghum. In pearl millet, both heat tolerance and drought-avoidance mechanisms appear well developed. Tests have shown that heat tolerance frequently correlates positively with desiccation tolerance, but because they do not always correlate, different mechanisms must be involved in each kind of tolerance. Heat hardening occurs under natural conditions and may contribute significantly to total plant performance. Once plants are heat hardened there may be long-lasting effects. The age or stage of development of the plants at which high-temperature exposure occurs may also have a marked influence on the response. The relative resistance to high-temperature injury may change among genotypes as they age. Leaf temperatures in the range of 43°–45°C may have marked effects on photosynthesis of sorghum, with distinct differences shown in genotype response. The response of hybrids to high temperatures may be determined by one or both parents. Photosynthesis by plants selected for high heat tolerance by a leaf-disc technique was shown to be more stable at high temperatures than that of plants with low heat tolerance. The leaf-disc technique may be used for rapid field screening.