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Showing posts with label chemicals. Show all posts
Showing posts with label chemicals. Show all posts

Thursday, August 9, 2012

Irreversibility leads to unsustainability


People in the chemical field will understand the concept of ‘irreversibility’. Certain chemical reactions can go only in one direction and but not in the reverse direction. But some reactions can go on either direction and we can manipulate such reactions to our advantages. This concept has been successfully used in designing many chemical reactions in the past and many innovative industrial and consumer products emerged out of it. But such irreversible reactions also have irreversible consequences because it can irreversibly damage the environment we live in. There is no way such damage can be reversed. That is why a new branch of science called ‘Green Chemistry’ is now emerging to address some of the damages caused by irreversible chemical reactions. It also helps to substitute many synthetic products with natural products. In the past many food colors were made out of coal tar known as coal tar dyes. These dyes are used even now in many commercial products. Most of such applications were merely based on commercial attractiveness rather than health issues. Many such products have deleterious health effects and few of them are carcinogenic. We learnt from past mistakes and moved on to new products with less health hazards. But the commercial world has grown into a power lobby who can even determine the fate of a country by influencing political leaders. Today our commercial and financial world has grown so powerful that they can even decides who can be the next president of a country rather than people and policies. They can even manipulate people’s opinion with powerful advertisements and propaganda tactics by flexing their financial muscles. Combustion of fossil fuel is one such example of ‘irreversibility’ because once we combust coal, oil or gas, it will be decomposed into oxides of Carbon, oxide of Nitrogen and also oxides of Sulfur and Phosphorous depending upon the source of fossil fuel and purification methods used. These greenhouse gases once emitted into the atmosphere we cannot recover them back. Coal once combusted it is no longer a coal. This critical fact is going to determine our future world for generations to come. Can we bring back billions of tons of Carbon we already emitted into the atmosphere from the time of our industrial revolution? Politicians will pretend not to answer these question and financial and industries lobby will evade these question by highlighting the ‘advancement made by industrial revolutions’. People need electricity and they have neither time nor resources to find an alternative on their own. It is open and free for all. People can be skeptical about these issues because it is ‘inconvenient for them’ to change But can we sustain such a situation? Irreversibility does not confine only to chemical reactions but also applies for the environment and sustainability because all are intricately interconnected.Minig industries have scared the earth, power plants polluted the air with greenhouse emission and chemical industries polluted water and these damages are irreversible. When minerals become metals, buried coal becomes power and water becomes toxic effluent then we leave behind an earth that will be uninhabitable for our future generations and all the living species in the world. Is it sustainable and can we call it progress and prosperity? Once we lose
pristine Nature by our irreversible actions then that is a perfect recipe for a disaster and no science or technology can save human species from extinction. One need not be scientist to understand these simple facts of life. Each traditional land owners such as Aborigines of Australia or Indians of America and shamans of Indonesia have traditionally known and passed on their knowledge for generations. They too are slowly becoming extinct species in our scientific world because of our irreversible actions. Renewability is the key to sustainability because renewability does not cause irreversible damage to Nature.

Monday, June 11, 2012

Innovative desalting technolgy for Chemical industries


Sodium chloride commonly known as ‘ common salt ‘ is a basic raw material for the production of a wide range of chemicals including Caustic soda and Soda ash. The cost of salt has been recently increasing steadily due to wide demand and supply gap all over the world. This in turn has increased the cost of all other chemicals derived from salt and this situation is expected to continue in future. Salt industry has been traditionally using a ‘solar evaporation’, an age old technique from antiquity. The technology involves pumping of seawater on large area of arid land and allowed to evaporate as the concentration of salt increases. The brine then passes on through the various ponds, with the sodium chloride content rising from 2% to 25%. This increasing salinity gives the ponds a distinctive pink color, as algae in strongly saline solutions produce a red pigment called haematochrome. The Red Sea is red for the same reason. The saturated brine is pumped to smaller ponds where nature continues its work of evaporation. Once the volume has been reduced to 10.2% of the original, any further concentration results in the deposition of sodium chloride. From September to February more brine is added until at least 25 mm of salt has settled and it is time for harvesting. The brine remaining (called "bitterns") is a saturated solution of NaCl, with the other salts present at concentrations well below saturation. This is pumped out to sea just before the harvest is gathered, as these ions would contaminate the salt if all the water were evaporated off. For four to six weeks beginning in early March, mechanical harvesters scoop up the crystallized salt and load it on to trucks that shuttle back and forth across the ponds to the washer. In the two washing plants the salt is washed in clean saturated brine, in which the other salts, present as impurities, dissolve. From there hundreds of tones of clean washed salt are discharged daily on to the stacks for storage - up to 10,000 tons per day. During winter no more salt is recovered, but the plant continues its regular work of processing and beggaring the stockpiled salt. But this raw salt has number of impurities such as Calcium, Magnesium and Sulfate ions which are harmful for the production of further chemicals. Though the cost of producing salt is cheaper by solar evaporation, the cost of purifying salt from above impurities and making suitable brine for chemical production is expensive .The cost of salt used in chemical processing industries after transportation and purification increase to whopping $ 200 and above. Many Asian countries such as Japan, South Korea, China, Taiwan and Indonesia are major importers of salt. The salt import by the above importers in Asia pacific region between 2000 and 2009 has increased by 6 million tonnes, equal to 40% or 4.6% per annum.In four years between 2005 and 2009, the price of salt increased by US$25/Mt, equal to 83% or 16% per annum.The average price of imported salt varies between US$40 to $47/Mt. (Ref: Salt partners). Erratic weather patterns, sea level rise, Tsunami, inundation, flooding and unseasonal rains have hampered salt production all over the world. The chemical industries are facing an uncertain future and unpredictable pricing of salt. Prolonged winter in Europe and US and other parts of the world have pushed the demand for salt for de-icing. India is the third largest and cheapest producer of salt in the world with lowest labor cost. But even in India, the prices of salt have gone up recently from Rs.600 to Rs.1000/Mt. An Australian company has developed and patented an innovative technology to solve the above problems. The company uses membrane technology to produce Sodium chloride brine directly from seawater suitable for all chemical products in the downstream. This novel technology separates seawater into salt and drinking water, after all seawater contains about 95% pure water. It can solve the problems of many mining companies in Australia who need Caustic soda as well as water for their processing.