scholarly journals Rootcrops processing waste management by Pyrolysis conversion

2020 ◽  
pp. 149-162
Author(s):  
Ramon Orias
Keyword(s):  
Heat Exchanger ◽  
Poor Performance ◽  
Pulp Fibers ◽  
Waste Products ◽  
Bed Porosity ◽  
Air Supply ◽  
Conducting Materials ◽  
Commercial Processing ◽  
Environmentally Sound ◽  
Root Tissues

The waste products derived from the commercial processing of root crops are the soiled peels, trimmings, root tissues, and by-products like pulp fibers obtained from the finishing operations. These bulky waste products create the management problems of safe storage and environmentally sound disposal. Processing the wastes from cassava was found to be the most suitable for pyrolysis conversion from among the rootcrops considered. Results showed that, of the four (4) cassava waste forms, larger briquette was found to have the highest vinegar yield conversion at 1.842L per kg while the shred form had the lowest at 1.203L per kg. The rate of vinegar production was also fastest from the briquettes at 2.388L per h and lowest from the raw form at 1.544L per h. Better vinegar yields were therefore associated with solid fuel forms, smaller bed porosity, smaller surface reaction area, and lower gasification temperature. Other factors that also affected vinegar production were the loading rates, air supply conditions, and heat exchanger efficiency. In this study, the available Logarithmic Mean Temperature Difference (LMTD) was only 45.67°C, indicative of poor performance of the exchanger unit. The heat exchanger unit’s design can be improved in future experiments by using good thermal conducting materials, reconfiguration, and increasing the conductor interface area. This should result in higher vinegar yields.

scholarly journals Solid oxide fuel cells power unit reformer/burner/heat-exchanger module experimental study

2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 631-640
Author(s):  
Vladimir Munts ◽  
Yulia Volkova ◽  
Mikhail Ershov ◽  
Vladimir Tuponogov ◽  
Nikita Plotnikov
Keyword(s):  
Fuel Cells ◽  
Heat Exchanger ◽  
Solid Oxide Fuel Cells ◽  
Power Unit ◽  
Partial Oxidation ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Experimental Procedure ◽  
Air Supply ◽  
Partial Oxidation Reforming

The article contains the installation description, experimental procedure, and results for the catalytic partial oxidation reformer/catalyst burner/heat-exchanger module. Mathematical modeling for all major blocks temperatures dependence on the reformer air supply ratio was carried out. In the air supply ratio range under study the model was verified using experimental data. The model was further practically used for the solid oxide fuel cells power unit automatic control modes development. The partial oxidation reforming solid oxide fuel cells power unit characteristics were evaluated.

Experimental investigation on drag reduction of flowing crop suspensions of the pulp fibers in circular pipe heat exchanger

2019 ◽  
Vol 38 (4) ◽  
pp. 443-453 ◽  
Author(s):  
Syed Muzamil Ahmed ◽  
Salim Newaz Kazi ◽  
Ghullamullah Khan ◽  
Naveed Akram ◽  
Mahidzal Dahari ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Heat Exchanger ◽  
Drag Reduction ◽  
Circular Pipe ◽  
Pulp Fibers ◽  
Pipe Heat

CRAC Heat Exchanger Response to Step Change in Chilled Water Flowrate

2009 ◽  
Author(s):  
Shawn P. Shields ◽  
Yogendra K. Joshi ◽  
Michael Patterson ◽  
Michael Meakins
Keyword(s):  
Experimental Data ◽  
Heat Exchanger ◽  
Flow Rate ◽  
Data Center ◽  
Temperature Response ◽  
Step Change ◽  
Outlet Temperature ◽  
Power Failure ◽  
Air Supply ◽  
Chilled Water

This paper presents experimental data showing the response of a computer room air conditioning unit (CRAC) to chilled water (CHW) pump restart. The data are offered to improve and develop modeling of cooling equipment restart events following data center power failure. There are estimates that power failures will increase and limits on availability will affect data center operations at more than 90 percent of all companies over the next five years. Because providing backup power to cooling equipment increases data center first cost, it is important to have accurate models for cooling events and processes following power failure that help predict server inlet temperatures during the transient phase caused by a power failure. Since power density of computing equipment continues to rise, the temperature rise of air within the data center has been predicted to rise more quickly to an unacceptable level, increasing concern. Accurate models of CRAC response to pump restart can aid in data center cooling design, backup power infrastructure provisioning, and even compute equipment selection by predicting the air supply temperature after the generator provides power to the chilled water pump. Previous transient models include zonal models with large time scales and CFD/HT models with boundary conditions developed for steady state. These models can be improved by comparison with experimental data. The experiment consists of measuring the response of the CRAC heat exchanger to the step change in CHW flow rate upon pump restart. Inlet and outlet temperatures of both CHW and air were measured, as well CHW flow rate. A point measurement of air at the CRAC fan outlet was also taken to verify that airflow remained relatively constant. Outlet temperatures from the CRAC follow a first order response curve; it is found that the CRAC under consideration has fan outlet temperature time constant of 10 seconds. A delay of 20 seconds is observed between the fan outlet temperature response and the CHW return temperature response.

Microbial cooperation improves bioleaching recovery rates

2018 ◽  
Vol 39 (1) ◽  
pp. 50 ◽  
Author(s):  
Melissa K Corbett ◽  
Elizabeth LJ Watkin
Keyword(s):  
Rare Earth ◽  
Mine Tailings ◽  
Global Markets ◽  
Low Grade ◽  
Mining Operations ◽  
Waste Products ◽  
New Novel ◽  
Increasing Demand ◽  
Environmentally Sound ◽  
Opening Up

Whilst bioleaching is primarily used to recover minerals from low-grade ores, the increasing demand for Rare Earth elements combined with supply chain concerns is opening up new avenues of extraction from mine tailings, waste products and recyclable materials. Exploration of new, novel and economically viable techniques are required to manage the coming shortage and volatility of global markets with more environmentally sound alternatives to traditional mining operations holding the key.

scholarly journals Numerical Research and Parametric Study on the Thermal Performance of a Vertical Earth-to-Air Heat Exchanger System

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Zhening Zhang ◽  
Jindong Sun ◽  
Zhenxing Zhang ◽  
Xinxin Jia ◽  
Yang Liu
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Geothermal Energy ◽  
Energy Utilization ◽  
Construction Costs ◽  
System A ◽  
Air Supply ◽  
Low Energy Buildings ◽  
New Type ◽  
Condensed Water

The earth-to-air heat exchanger (EAHE) system, as a clean and efficient shallow geothermal energy application technology, has obvious effects in reducing the energy consumption of passive low-energy buildings. The traditional horizontal EAHE system is difficult to apply and popularize due to its large occupation, unfavorable shallow soil temperature, and difficulty in timely centralized discharge of condensed water. This paper proposes a new type of vertical earth-to-air heat exchanger (VEAHE) system. The VEAHE system has a number of advantages such as smaller occupation, efficient geothermal energy utilization, and centralized discharge of condensed water. In order to evaluate the influence of different parameters on the thermal performance of the VEAHE system, a mathematical model of the VEAHE system was developed. And, the data calculated by the model highly tallied with the experimental data. The results showed that laying thermal insulation layers at the outlet of risers will effectively restrain the interference of downcomers to risers. It is advisable to set thickness and length of the insulation layer at 30 mm and 3 m. Considering the compromise between thermal performance and construction costs of the VEAHE system, the length of the ducts at 30–50 m and the diameter at 150–250 mm are recommended. The air supply volume of a single shaft can reach 500–1200 m3/h as the air velocity reaches 3–7 m/s.

Numerical Investigation of Micro-Channeled Louver Fin Aluminum Heat Exchangers at Low Reynolds Number

2016 ◽  
Author(s):  
Pradeep Shinde ◽  
Mirko Schäfer ◽  
Cheng-Xian Lin
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Low Reynolds Number ◽  
Poor Performance ◽  
Geometrical Parameters ◽  
Number Range ◽  
Reynolds Number Range ◽  
Low Reynolds

Extensive studies are being carried out by several researchers on the performance prediction of aluminum heat exchangers with different fin and tube geometrical configurations mostly for Reynolds number higher than 100. In the present study, the air-side heat transfer and pressure drop characteristics of the louvered fin micro-channeled, Aluminum heat exchangers are systematically analyzed by a 3D numerical simulation for very low Reynolds number from 25 to 200. Three different heat exchanger geometries obtained for the experimental investigation purposes with constant fin pitch (14 fins per inch) but varied fin geometrical parameters (fin height, fin thickness, louver pitch, louver angle, louver length and flow depth) are numerically investigated. The performance of the heat exchangers is predicted by calculating Colburn j factor and Fanning friction f factor. The effect of fin geometrical parameters on the heat exchanger performance at the Reynolds number range specified is evaluated. The air-side performance of the studied heat exchangers for the specified Reynolds number range is compared with experimental heat exchanger performance data available in the open literature and a good agreement is observed. The present results show that at the studied range of Reynolds number the flow through the heat exchanger is fin directed rather than the louver directed and therefore the heat exchanger shows poor performance. The effect of geometrical parameters on the average heat transfer coefficient is computed and design curves are obtained which can be used to predict the heat transfer performance for a given geometry.

scholarly journals The influence of flow modification on air and PCM temperatures in an accumulative heat exchanger

2018 ◽  
Vol 180 ◽  
pp. 02011
Author(s):  
Marcin Borcuch ◽  
Michał Musiał ◽  
Karol Sztekler ◽  
Wojciech Kalawa ◽  
Stanisław Gumuła ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Temperature Distribution ◽  
Short Description ◽  
Pressure Drops ◽  
Flow Modification ◽  
Air Supply ◽  
And Control ◽  
Measurement And Control ◽  
Supply Systems ◽  
Change Material

The paper presents the influence of flow modification on the operation of an accumulative heat exchanger. This device can be used as a regenerator in ventilation and air supply systems. A heat exchanger uses ceresine (a mixture of paraffins) as a phase change material (PCM). The aim of this research was to determine the effect of flow modification on temperature distribution and pressure drops in the device. The introduction contains a short description of the test stand used, including the accumulative heat exchanger, the guide vanes, and the locations of measurement and control equipment. We found that additional objects limited vortex structures, increased the inside temperature, and dropped the pressure along the heat exchanger. Guidelines for further research are proposed and briefly discussed.

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