Nanofluids: Thermal Applications
Over the last few years nanofluids have attracted much attention because of their potential as high performance heat transfer fluids. Nanofluids are a new class of fluids made of a base fluids and nanoparticles (1 – 100 nm size particles). Nanofluids are often termed as ‘smart fluid’ due to its multifarious application and ‘smart functioning’. It has significant application in enhancement of the performance of the conventional heat transfer fluids. The research focus is on preparation, thermo-physical properties and the applications of the nanofluids.
Literature
shows that temperature, pH, surface modifiers, base liquids, morphology of the
nanoparticle have major role over the change of thermal conductivity, heat
transfer coefficient, viscosity, specific heat and density of the nanofluids.
Increase of temperature results in the increase the Brownian motion of the
particle, which leads to collision between the particles, and
finally helps in the enhancement of the thermal conductivity of the nanofluids.
Applications of the nanofluids include refrigeration, fuel cells,
air-conditioning, microelectronics, microchannels, miniature cryodevice, engine cooling/vehicle thermal management, manufacturing of high quality
lubricants and oil, power electronics, pharmaceutical processes,
transportation, nuclear engineering, heat pipes, heat exchanger, heat pump
systems, etc. It is also useful in nuclear power stations as a
coolant where removal of heat is needed at a very high rate. In the recent
years it has been shown that some nanofluids have successfully been formulated
and applied in enhanced oil recovery process, anticorrosive coatings and
drilling technology.
Overall
the literature in this research area spread over the wide range of discipline
including material science, chemical engineering, mechanical engineering,
synthetic chemistry and bio-applications.
1. Kumar,
S.; Chakrabarti, S. Inter. J. Eng. Res. Tech. 2014, 3(4), 549-557.
2. Das,
S.K.; Choi, S. U. S.; Patel, H. Heat
Transfer Eng. 2007. 27(10), 3-19.
3. Godson, L.; Raja, B.; MohanLal, D.; Wongwises, S. Renew. Sust. Energ. Rev. 2010, 14, 629–641.
Hydrolysis: Conversion of Starch to Glucose
Starch
is the principle component of potato, arrowroot, tapioca, maize, rice, wheat,
etc. In industrial scale starch is mainly used to convert sugar syrups which
are employed by the food industry to make sweets, juices and drinks. It was reported that bio-ethanol can be produced from starch generated from
cereal grains, potato, sweet potato, and cassava. Maximum
commercial production of starch is produced from potato. Potato is a seasonal
vegetable produced in huge quantity and a considerable amount is not
effectively used. During the season some of the potato are being wasted and the
farmer do not get proper value. The rotten potato creates pollution in the
rural area. Apart from consuming as edible item the alternative use of it has
been explored. Industrially hydrolysis of starch has long been used for the
conversion into food, beverages, and chemicals.
Hydrolysis of starch to glucose and
subsequent conversion to alcohol is very promising proposition. With this
objective the project can be implemented.
References:
1. K. Othmer, Encyclopedia of Chemical Technology, Wiley,
New York, 3rd edn., 1980, p. 499.
2. Taherzadeh M. J. and Karimi K. Acid
based hydrolysis processes for ethanol from lingo cellulosic materials: A
Review, Bioresources 2007, 2(3), 472-499.
Coir Pith: A Plant Growing Medium
India is one of the leading
countries in coconut in terms of production and productivity. India is the 3rd
largest coconut producing country in the world with an annual production of
more than 21,500 million tonnes nuts. In India coconut is produced in more than
15 states and Union Territories. Tamil Nadu, Kerela, Karnataka, Andhra Pradesh
are some of the leading coconut producing states in India. Among all the
coconut producing states Tamil Nadu contributes about 31% of the total coconut
production in India. Production increases about 11516 fruits/hectre in
2017-2018 as compared to the production of 10122 fruits/hectre in 2013-2014.
Coconut cultivation has been spread to new areas. In many states a total of
additional 13117 hectares new area was brought under coconut cultivation till
2014-2018. Indonesia, Phillipines, Brazil, Srilanka are some of the top coconut
producing countries globally. In terms of area coconut leads among all. The
member countries of the Asian and Pacific coconut community occupy 10.691
million hectare which contribute 87.9% of the total area under coconut.
Coir
pith is a byproduct of coconut industries. These are the bio-degradable residue
generated after the extraction of long fibres from coconut husks. About 2 kg of
coir pith is extracted from every kg of coir fibre extracted. Coirpith
constitute about 70% of the coconut husk. 7.5 million tonnes of coir pith are
produced per annum in India. The annual production of coir pith in Tamil Nadu
is 0.2 million. Coir Pith contains (C/N) ratio together with 35%
to 54% lignin content. The piths are fluffy, light, and spongy
material. Coir Pith has high water retention capacity as the cell structure is
porous. Due to the presence of macro and micro nutrients coir pith is
considered as fertile nutrients for plant growth medium. As the coir pith have
ligno-cellulosic material and low ash content, they decompose easily in soil as
they have pentosan/lignin ratio of 1:0.3. Due to the presence of pores it gives
an excellent aeration and drainage system and considered superior to peat.
Coir
Pith is considered as a waste in the coir factory. When this bio- waste is
disposed openly, it acts as a bacteria growing medium and results in poor
hygeine of the surrounding areas. When dumped into water bodies, it affects the
aquatic life due to the decay of coir pith. For this reason safe disposal of
coir pith is necessary. Coir Pith was treated as the component of cementious
materials after studying its various properties such as hygric strength, compressive
and bending strength. As it was difficult to decompose, Vermi-composting was
applied on coir pith when mixed with a certain amount of cow dung. It turned
out to be an important organic manure for agricultural fields, growing
vegetables etc. Also to use coir pith as an organic input in crop production it
was co-composted with solid poultry manure. Studies were done on coir pith
degraded by the fungus Pleurotus sajor caju, as it has the ability to slowly
degrade the coir pith and is capable of detoxifying phenolic compounds by
producing biopolymerizing enzyme. Many experimental observations were done for
the stabilisation of fine grained soil using cinder and coir pith.
This
coir pith can be applied as a plant growing medium. But, before using coir pith
for this purpose different property such as pH, electrical conductivity, and
moisture retentivity, etc should be checked. This area can be explored further
for the commercial use of the coir pith in large quantity.
References
1. Jana P., Boxi S. S. “Studies on pH, Conductivity, and Moisture Retention Capacity of Coir Pith for Its Application as the Plant Growing Medium.”Journal of Natural Fibers, 2020, doi.org/10.1080/15440478.2020.1827118.
2. Kamaraj C M. Exportable Coir products in Tamil Nadu. (1994), The Coconut Wealth.
3. Abad M., Noguera P., Puchades R., Maquieira A. Noguera V. (2002). Physico-chemical and chemical properties of some coconut coir dust for use as a peat substitute for containerized ornamental plants. Bioresources Technology 2002, 82: 241 – 245.
No comments:
Post a Comment