Effect of an axial-radial plate reactor modifications on a mega methanol plant production

Author(s):  
Zahra Eksiri ◽  
Mohammadreza Mozdianfard ◽  
Azadeh Mirvakili ◽  
Mohammadreza Rahimpour

Abstract Axial-radial flow plate reactors have been recently considered as efficient and practical types of reactors for methanol synthesis. Generally, an axial–radial reactor (AR) consists of two main parts namely the axial section and the radial section and the vast majority of the feed enters the radial section. Moreover, the structure of AR has a space above the axial part, which can add an adiabatic bed in the system. In this study, the performance of two novels AR configurations is investigated to improve the effectiveness of the axial–radial plate reactor. In the first configuration, the optimum length of the adiabatic bed is calculated and the adiabatic bed is located above the axial section inside the AR and is named IAAR. Therefore, in IAAR the feed of the axial section just enters the adiabatic bed and warms up. On the other configuration, the adiabatic bed with the optimum length is placed outside the reactor and is named OAAR. Therefore, in OAAR the total feed passes through the adiabatic bed, highly warms up, then cools to the optimum temperature in a heat exchanger, and finally enters AR. Two-dimensional mathematical modeling via orthogonal collocation on the finite element method is developed to compare the performance of two configurations. The results show that the maximum proportion of methanol produces in IAAR, which is approximately 3.8% higher than that produced in conventional AR due to utilizing an adiabatic bed inside the AR and superior gas distribution in the process. Momentum, mass, and heat equations are calculated and molar flow rates, mole fractions and temperatures are depicted along the radius and the length of the three configurations.

2015 ◽  
Vol 6 (2) ◽  
pp. 89-93
Author(s):  
S. Bodzás ◽  
I. Dudás

The objectives of this publication are the analysis of surfaces and edges of a new geometric spiroid hob with arched profile in axial section and the definition of their equations for computer modelling. On the basis of this we will work out the CAD model of hob for our further geometric calculations.


2013 ◽  
Vol 41 (3) ◽  
pp. 174-195 ◽  
Author(s):  
Anuwat Suwannachit ◽  
Udo Nackenhorst

ABSTRACT A new computational technique for the thermomechanical analysis of tires in stationary rolling contact is suggested. Different from the existing approaches, the proposed method uses the constitutive description of tire rubber components, such as large deformations, viscous hysteresis, dynamic stiffening, internal heating, and temperature dependency. A thermoviscoelastic constitutive model, which incorporates all the mentioned effects and their numerical aspects, is presented. An isentropic operator-split algorithm, which ensures numerical stability, was chosen for solving the coupled mechanical and energy balance equations. For the stationary rolling-contact analysis, the constitutive model presented and the operator-split algorithm are embedded into the Arbitrary Lagrangian Eulerian (ALE)–relative kinematic framework. The flow of material particles and their inelastic history within the spatially fixed mesh is described by using the recently developed numerical technique based on the Time Discontinuous Galerkin (TDG) method. For the efficient numerical solutions, a three-phase, staggered scheme is introduced. First, the nonlinear, mechanical subproblem is solved using inelastic constitutive equations. Next, deformations are transferred to the subsequent thermal phase for the solution of the heat equations concerning the internal dissipation as a source term. In the third step, the history of each material particle, i.e., each internal variable, is transported through the fixed mesh corresponding to the convective velocities. Finally, some numerical tests with an inelastic rubber wheel and a car tire model are presented.


1998 ◽  
Vol 16 (3) ◽  
pp. 182-188
Author(s):  
Kelly M. Groves ◽  
Stuart L. Warren ◽  
Ted E. Bilderback

Abstract Rooted cuttings of Cotoneaster dammeri Schneid ‘Skogholm’ and seedlings of Rudbeckia fulgida Ait. ‘Goldsturm’ were potted into 3.8 liter (4 qt) containers in a pine bark:sand (8:1 by vol) substrate incorporated with 3.5 g (0.12 oz) N per container provided by one of the following five controlled-release fertilizers (CRFs): Meister 21N–3.5P–11.1K (21–7–14), Osmocote 24N–2.0P–5.6K (24–4–7), Scotts 23N–2.0P–6.4K (23–4–8), Sustane 5N–0.9P–3.3K (5–2–4) or Woodace 21N–3.0P–9.5K (21–6–12). Two hundred ml (0.3 in), 400 ml (0.6 in), 800 ml (1.1 in) or 1200 ml (1.7 in) of water was applied once daily (single) or in two equal applications with a 2 hr interval between applications (cyclic). Substrate solutions were collected from containers of cotoneaster 15, 32, 45, 60, 74, 90, 105, and 119 days after initiation (DAI). Irrigation efficiency [(water applied − water leached) ÷ water applied] was determined on the same days. Cyclic application improved irrigation efficiency at 800 ml (1.1 in) and 1200 ml (1.7 in) ≈ 27% compared to a single application. Irrigation efficiencies averaged over the season were 95%, 84%, 62%, and 48% for cotoneaster and 100%, 90%, 72%, and 51% for rudbeckia at 200 ml (0.3 in), 400 ml (0.6 in), 800 ml (1.1 in) and 1200 ml (1.7 in), respectively. NH4-N and NO3-N and PO4-P concentrations in substrate solution decreased with increasing irrigation volume regardless of CRF. Substrate NH4-N concentration decreased throughout the season with most CRFs below 5 mg/liter by 90 DAI. CRFs mainly affected substrate NH4-N and NO3-N concentrations when irrigated with 200 ml (0.3 in) or 400 ml (0.6 in). Substrate NH4-N, NO3-N, and PO4-P solution concentrations were similar for all CRFs at irrigation volume of 1200 ml (1.7 in). Osmocote, Scotts, and Woodace maintained relatively constant substrate solution levels of PO4-P through 60 DAI. By 90 DAI, substrate PO4-P levels were similar regardless of irrigation volume or CRF. Substrate PO4-P concentrations were never in the recommended range of 5 to 10 mg/liter when irrigated with 800 ml (1.1 in) or 1200 ml (1.7 in) regardless of CRF. Solution pH remained in the recommended range of 5.0 to 6.0 for all irrigation volumes and CRFs throughout the entire study with the exception of Sustane.


2011 ◽  
Vol 66 (1) ◽  
Author(s):  
Jerzy Kupiec ◽  
Agnieszka Zdanowska ◽  
Janina Zbierska ◽  
Aleksandra Woźniak
Keyword(s):  

2011 ◽  
Vol 28 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Jan Frelich ◽  
Martin Šlachta ◽  
František Střeleček ◽  
Jana Lososová

Profitability of dairy farming in relation to the type of feeding systemWe investigated the profitability of dairy farms in relation to the type of feeding system (seasonal pasture vs. permanent housing). An economic analysis was carried out of data on the structure and financial health of 50 farms in 2007 using questionnaires filled in by the farmers. The Principal Component Analysis (PCA) was applied to reveal causal relationships between a number of characteristics of the farms. The two axis of PCA explained 40.48% and 16.13% of the variability among the selected farm characteristics. Profitability related more to the number of subsidies, the area of arable land, the number of livestock and to the milk and plant production than to the area of meadows and pastures. Although a better cow performance was achieved on farms with confined herds, the profit per agricultural area and profit rate did not differ significantly between the two feeding strategies (P>0.05). The profit was 3,259 and 3,655 CZK/ha on average and the profit rate 7.9% and 5.6% on average on farms with pastured herds and on farms with confined herds, respectively. A lowering of input costs and a more effective utilisation of grasslands may further enhance profitability.


Author(s):  
S.V. Chernobai ◽  
V.K. Riabchun ◽  
T.B. Kapustina ◽  
V.S. Melnyk ◽  
O.E. Shchechenko

Goal. To build up a spring triticale genetic bank to provide breeding, scientific and educational institutions with initial material and to preserve the existing diversity. To update the database of accessions with a set of valuable economic and morphological features. Results and discussion. The methodology and results of the collection formation and evaluation of spring triticale accessions in the National Center for Plant Genetic Resources of Ukraine of Plant Production Institute nd. a V. Ya. Yuriev are presented. The formed collection includes 1,935 accessions from 27 countries: 42 varieties and 1,478 breeding lines from Ukraine, 92 varieties and 248 lines from foreign countries and also 75 genetic lines. The collection was formed by major valuable economic features (plant height, growing season length, spike threshing, yield, 1000-grain weight, disease resistance, technological properties, etc.). Accessions with the majority of morpho-biological and valuable economic features were selected. All the accessions in the collection are certificated. 1,762 accessions were packed for storage into the National Depository; 1,507 of them were packed for long-term storage. Conclusions. The gene pool of spring triticale from the collection of the Gene Bank of Plants of Ukraine is widely used for breeding. This allows conducting hybridization of genetically and ecologically remote forms with various expressions of features and obtaining whole new breeding material. Involvement of collection accessions in breeding allows generating new genetic sources of valuable economic features.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 523b-523 ◽  
Author(s):  
Erin James ◽  
Marc van Iersel

The quantity and quality of available water in the Southeastern United States continues to decline as demands on limited resources increase. Growers will soon be forced to comply with legal limitations on water consumption and limits on nutrient runoff from their operations. A lack of information on standard growing practices using alternative irrigation systems such as ebb and flow is hindering their acceptance and implementation. We are currently conducting a series of experiments to establish basic growing guidelines for the use of ebb and flow in the greenhouse in bedding plant production. In the third of these experiments, Petunia × hybrida Hort. Vilm.-Andr. `Blue Frost' and Begonia × hiemalis Fotsch. `Ambassador Scarlet' were grown for 5 weeks on ebb and flow tables with fertigation solutions (225 ppm N) containing three different levels of phosphorus (0, 50, and 100 ppm). Three soilless media were also used, which varied in their percentage content of vermiculite, perlite, pine bark and coconut coir. For both the begonias and petunias dry mass of the shoot was greatest in plants grown with higher levels of phosphorus. In comparison to plants grown with 0 ppm phosphorous, petunias and begonias grown with 50 or 100 ppm P were 44% and 25% greater in mass, respectively. However, begonias had 38% more flowers when fertigated with the higher levels of phosphorous while petunias flowered earlier with 0 ppm P fertigation solution. The electrical conductivity of the media did not change significantly over the course of the growing period, but the pH dropped by an average of 1 over the same time interval.


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