scholarly journals Thermal measurement and degradation quantification of teeming ladle refractories and the effects on the process

2021 ◽  
Author(s):  
◽  
Liam Cotton

The key objective of the thesis was to quantify the heat loss caused to the liquid steel due to the cooling effect of the teeming ladle refractories. It was previously hypothesised that the in-situ degradation of insulation layer would increase this cooling effect. To determine the cooling effect of the degraded insulation material it was first thermally characterised with in-situ thermocouple measurements. Post-mortem samples were recovered from the teeming ladles used for the thermocouple measurements during their regular production cycles in a BOS plant. The post-mortem samples were then tested for their thermophysical properties. From this it was possible to determine the density increased from 260kg/m3 to 759.6 kg/m3, the thermal conductivity increased from 0.039W/m.K to 0.15W/m.K and the specific heat capacity decreased by 40% compared to its original state. These findings were then used to calculate the increased heat loss rate of the refractory material in the teeming ladle, which then in turn causes increased heat loss to the steel transported by the ladle. A thermal model was used to determine the heat flux stored in a fully saturated ladle and then different time periods of cooling with and without a lid. The effect of teeming ladle lids reduced the heat losses by up to 11°C per cycle compared to a ladle without a lid. Whereas the heat loss due to the insulative layer degradation was calculated to be <1°C for the initial heats before the ladle reached production temperatures and, therefore, had minimal effect. However, the degradation did show an increase in teeming ladle shell temperatures, which needs to be taken into account for service temperature monitoring. The thermal profiles of the modelled scenarios showed that if an accurate hot face measurement could be achieved it would be possible to accurately predict the cooling effect of each teeming ladle in production. This study was able to accurately measure the refractories and slag taken from a teeming and utilise the geometry of the ladle to reduce the error from thermal imaging. Previously predictions were used that could cause errors up to ±175°C when taking thermal images of the teeming ladle hot face. Through the method adopted in this study it was possible to take accurate measurements of the hot face within ±5°C. This can now be utilised by a thermal model to make accurate real time predictions of the heat loss caused by teeming ladle refractories. Thereby reducing the reheating required and improving the quality of steel produced.

2016 ◽  
Vol 94 (suppl_1) ◽  
pp. 27-27
Author(s):  
W. B. Smith ◽  
J. L. Foster ◽  
K. C. McCuistion ◽  
S. J. Abatti ◽  
M. Lesak ◽  
...  

2002 ◽  
pp. 347-353
Author(s):  
M.M. Murillo ◽  
J.M. Fuentes ◽  
F. Borrego ◽  
A. Flores Uruza ◽  
H. Díaz ◽  
...  

2008 ◽  
Vol 88 (4) ◽  
pp. 711-719 ◽  
Author(s):  
Kenton J Hart ◽  
Brian G Rossnagel ◽  
Peiqiang Yu

The objective of this study was to compare the most widely grown barley cultivar in Canada, AC Metcalfe, a malting type barley, with five feed cultivars. Barley cultivars were grown at one location during 3 consecutive years and barley samples were milled to pass through a 1-mm screen and analysed to determine nutritive value. Additional samples were passed through a roller mill with a gap set at 1.12 mm and incubated ruminally for 0, 2, 4, 8, 12, 24, and 48 h in 3 dry Holstein cows fitted with rumen cannulae. The rate and extent of rumen digestion were estimated. AC Metcalfe had a higher (P < 0.001) concentration of NDF, and lower (P < 0.05) concentrations of non structural carbohydrates, starch, ADF, total digestible nutrients, and fermentable cell wall carbohydrates compared with the mean of the feed cultivars. The malting cultivar had a higher (P < 0.001) soluble DM fraction, lower (P < 0.05) CP and starch degradation rates, and a lower (P < 0.001) ruminally degradable starch concentration compared with the mean of the five feed cultivars. The results demonstrate that there are only small differences in terms of chemical composition and in situ degradation kinetics between the malting cultivar AC Metcalfe and the five feed cultivars of barley reported here. Key words: Barley, energy, protein, ruminants


1998 ◽  
Vol 1998 ◽  
pp. 127-127
Author(s):  
B M L McLean ◽  
J J Hyslop ◽  
A C Longland ◽  
D Cuddeford

Cereal grains are often subjected to physical processing before being fed to equids. However, little information is available on how physical processing of cereals affects degradation dynamics in equids. This experiment examines the effect of two physical processing methods (micronisation and extrusion) on in situ degradation of barley in the caecum of poniesThree caecally fistulated mature Welsh-cross pony geldings (approx. LW 270kg) were offered ad libitum grass hay plus minerals. Incubation bags (monofilament polyester 6.5 x 20cm, 41μm pores, 16mg/cm2 sample size) containing either unprocessed barley (UB), micronised barley (MB) or extruded barley (EB) were incubated in the caecum for fixed times according to both a forward (0, 2, 4, 6, 12, 8, 24, 48h) and reverse (48, 24, 8, 4, 12, 6, 2, 0h) incubation sequence. For each feedstuff residues from each time were bulked within pony and across incubation sequence for subsequent analysis of dry matter (DM) and starch (STC). Degradation profiles were fitted to the DM and STC disappearance data according to Ørskov and McDonald (1979).


Author(s):  
Catherine L Lockard ◽  
Caleb G Lockard ◽  
Wyatt N Smith ◽  
Kendall J Karr ◽  
Ben P Holland ◽  
...  

Abstract Six ruminally cannulated steers (average BW = 791 + 71 kg) were used in a replicated 3 × 3 Latin square experiment to determine the effects of roughage type on rumination, fiber mat characteristics, and rumen fermentation variables. Three roughages were included at 7% (DM basis) in a steam flaked corn-based diet; cotton burrs (CB), wheat silage (WS), or corn stalks (CS). Steers were fitted with a sensory collar to record rumination behaviors in 2-h intervals at the beginning of the experiment. Each 30-d period consisted of a 7-d of recovery, 14-d of diet adaptation, 7-d of rumination data collection (daily and bi-hourly average rumination), 1-d of rumen fluid collection, and 1-d of rumen evacuations. In situ degradation of individual roughages was determined for 4-d after period 3 evacuations. During rumen evacuations, ruminal contents were removed; the rumen fiber mat (RF) was separated from the liquid portion with a 2 mm sieve, weighed, and a subsample was dried. Data were analyzed using the MIXED procedure of SAS with steer as the experimental unit and roughage (CB, WS, and CS) as the main effect. Dry matter intake (DMI) was not different for CB and WS (P = 0.25) and greatest for steers consuming CS diet (P  &lt; 0.01). Roughage type did not influence the weight of the RF dry matter (%; DM; P = 0.92), RF weight (P = 0.69), or RF:DMI ratio (P = 0.29). Daily rumination (min/d) did not differ among roughages (P = 0.40), but min of rumination/kg of DMI was greatest for CS (18.0 min), min/kg of NDF was greatest for WS (89.8 min; P = 0.02), and min/kg of peNDF was greatest for CS (132.4 min; P  &lt; 0.01). Wheat silage had the greatest percentage of soluble DM and CB-R and CS-R (P  &lt; 0.01) had the greatest ruminal degraded DM fraction. Rumen fiber mat did not differ for roughages, although rumination min/kg of DMI and peNDF was greatest for steers consuming CS and WS. In situ degradation determined that CB-R and CS-R had the greatest percentage of ruminal degraded DM. Based on the objective of the experiment, roughage type did not influence daily rumination or fiber mat characteristics.


Author(s):  
Soheil Manouchehri

For un-bonded (sliding) Pipe-In-Pipe (PIP) systems, one of the main components is the centralizers (also called spacers). The main functions of the centralizers are to centralize the inner pipe inside the outer pipe, to transfer the loads between inner pipe and outer pipe and to safeguard the insulation material in the annulus from excessive compression during fabrication, installation and operation. Centralizers must also have good thermal insulation properties so that the heat loss is minimized. Different designs are now available for centralizers but the majority are based on two half shells which are bolted together. During fabrication, installation and operation, centralizers subject to different loads under which they are required to continue functioning properly. This paper provides an overview of centralizer design aspects and then focuses on the loading history during installation using reeling method. The main contributing parameters to centralizer loading during reeled installation technique are discussed and conclusions are drawn. It is believed that this will enable Pipeline Engineers to select the most appropriate material and design for centralizers.


2016 ◽  
Vol 41 (1) ◽  
pp. 28-36 ◽  
Author(s):  
F. F. Sani ◽  
L. K. Nuswantara ◽  
E. Pangestu ◽  
F. Wahyono ◽  
J. Achmadi

Two adult male sheeps fitted with rumen cannula were used in two experiments to study the effects of synchronization of carbohydrate and nitrogen supply in sugarcane bagasse based total mixed ration (TMR) on in situ nutrient degradation. The first experiment was aimed to create three TMR with different synchronization index. Ingredient feedstuffs of TMR were evaluated for its in situ organic matter (OM) and nitrogen (N) degradation kinetics. On the basis of the OM and N degradation kinetics of feedstuffs, three sugarcane bagasse based TMR were formulated with synchronization indexes of 0.37; 0.50; and 0.63; respectively. The TMR had similar levels of crude protein (CP), total digestible nutrients, and neutral detergent fiber (NDF). In the second experiment, the three TMR with different synchronization index were evaluated for in situ degradability characteristics of OM, CP, NDF, and sulfur. The in situ degradation of OM in TMR were decreased (P<0.05) with the increasing of synchronization index. The higher synchronization index in TMR increased (P<0.05) CP degradation of CP. The NDF degradation decreased slightly by the alteration of synchronization index in TMR. The higher synchronization index in TMR reduced (P<0.05) in situ sulfur degradation, and this may not support to effects of synchronization of carbohydrate and nitrogen supply.  


1992 ◽  
Vol 72 (1) ◽  
pp. 71-81 ◽  
Author(s):  
B. M. Mosimanyana ◽  
D. N. Mowat

The effects of processing variables on soybean crude protein (CP) ruminal degradation were investigated. Soybean meal (SBM) was heated in a forced-air oven (90 °C, 1 h) with blood (0, 5, 10 and 20% dry matter) and/or xylose (3 mol mol−1 SBM-blood lysine) in a randomized complete block design. In another experiment, whole soybeans were utilized using the following treatments: raw; roasted (in Gem Co. unit exit temperature 150 °C) and steeped for 0 or 2 h; roasted, flaked (exit temperature 111 °C) and steeped for 0, 1, 2, 3 h or 1 h with 4% xylose and/or 10% blood. Solubility of SBM CP was reduced (P < 0.01) by the addition of xylose, without adverse effects on pepsin-digestible CP and acid detergent insoluble nitrogen. In situ degradation of CP (EDCP), assuming a passage rate of 5% h−1, of SBM was reduced by the addition of blood (P < 0.05) and particularly xylose (P < 0.01). Soybean CP solubility was reduced (P < 0.01) by roasting and flaking (65.6 vs. 17.6% total CP). Not flaking the roasted beans further reduced (P < 0.01) CP solubility (to 10.4%) probably due to less rapid cooling. The EDCP of raw soybeans (87.6%) was reduced by roasting (64.2%), steeping whole (57.6%) or flaked (61.1%) beans. These data support xylose to effectively reduce ruminal degradation of SBM and simple steeping (1 h) with or without flaking to further reduce EDCP of roasted soybeans. Key words: Soybean meal, soybeans, xylose, blood, steeping, protein degradation


2020 ◽  
Vol 70 (1) ◽  
Author(s):  
Xiujie Gong ◽  
Hongtao Zou ◽  
Chunrong Qian ◽  
Yang Yu ◽  
Yubo Hao ◽  
...  

Abstract Purpose The highly efficient degradation bacteria were selected from the humus from the very cold straw in China for many years to construct the in situ degradation bacteria, and the degradation efficiency of corn straw was determined by process optimization. Methods According to the main components of corn straw, through morphological, physiological, and biochemical screening, three highly efficient complementary degradation strains were selected to construct the compound flora, and the degradation efficiency was analyzed by Fourier transform infrared spectrometer, field emission scanning electron microscope, and X-ray diffractometer. Result The corn straw selected in this paper is mainly composed of cellulose (31.99%), hemicellulose (25.33%), and lignin (14.67%). Through the determination of enzyme activity, strain Streptomyces sp. G1T has high decomposition ability to cellulose and hemicellulose but weak utilization ability to lignin; strain Streptomyces sp. G2T has the strongest decomposition ability to cellulose and hemicellulose among the three strains. The decomposition ability of strain Streptomyces sp. G3T to lignin was the strongest among the three strains. Therefore, by compounding the three strains, the decomposition ability has been greatly improved. The optimal process conditions obtained by single factor and response surface method are as follows: pH is 7, temperature is 30 °C, inoculation amount is 5%, rotational speed is 210 rpm, and the weight loss rate of straw is 60.55% after decomposing for 7 days. A large amount of degradation of corn straw can be seen by Fourier transform infrared spectrometer, field emission scanning electron microscope, and X-ray diffractometer. Conclusion Streptomyces sp. G1T, Streptomyces sp. G2T, and Streptomyces sp. G3T screened from straw humus in very cold areas were used to construct in situ degradation bacteria, which had good straw degradation activity and had the potential to be used for straw treatment in cold areas after harvest. This characteristic makes the complex bacteria become a strong competitive candidate for industrial production, and it is also an effective biotechnology in line with the current recycling of resources.


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