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Showing posts with label #Carbon recycling technology # CEWT # renewable hydrogen # seawater desalination # dissolved inorganic Carbon. Show all posts
Showing posts with label #Carbon recycling technology # CEWT # renewable hydrogen # seawater desalination # dissolved inorganic Carbon. Show all posts

Wednesday, April 5, 2023

How desalination plants contribute to global warming and solutions to address them?

How desalination plants contribute to global warming and solutions to address them? I posted the following article in my blog in 2014. We are now addressing this problem by setting one the largest integrated membrane-based sea water desalination plants in India using renewable power without using oil and gas. Highly contaminated and concentrated effluent discharge from existing and operating desalination plants around the world have greatly contributed to global warming according to world’s leading research institutions in marine science and oceanography. The ocean’s circulation which acts as conveyor belt distributes the increasing salinity and temperature of the sea across the globe. Several companies are researching on solutions to address the above problem and to achieve a Zero Liquid Discharge (ZLD) concept. Concepts such as FO (forward osmosis), OARO (osmosis assisted RO), NF pre-treatment with EDR, recovery of minerals such as Potassium chloride, Magnesium chloride (a precursor for extraction of Magnesium metal), Lithium chloride, Bromine etc. Theoretically all these solutions are encouraging but when to come to practise there are several hurdles to get over. Currently the most popular SWRO process is to recover 40% fresh water from seawater and discharge the balance 60% with twice its salinity and contaminated chemical are discharged in the sea. Such practice is going on since sixties when RO membranes were introduced. SWRO is an energy intensive process along with thermal evaporation they contribute to a great amount of green house gases. Despite several improvements in energy conservation in membrane processes the emissions of GHG was never addressed till date. Meanwhile several large-scale desalination plants are planned and implemented to overcome severe shortage of fresh water especially in African countries and pacific island and many arid regions of the world. We in CEWT are introducing CAPZ (clean water at affordable price with zero discharge) desalination a proprietary technology that not only achieve the highest recovery of fresh water from sea water but also generates simultaneously a highly value added ultrapure saturated Sodium chloride brine that serves as feed stock for chloralkaline industries substituting ‘solar evaporated salt’ as a source of Sodium. The pure saturated Sodium chloride brine is the feedstock to produce Caustic soda using membrane electrolysis as well as to produce Soda ash using Solvay process. Modern chloralkaline plants are very large in scales of operation which requires large quantities of solar salts. Due to climate change and unseasonal monsoon rains that have severely affected the solar salt production world-wide leaving a large gap between demand and supply. It has sharply increased the price of solar salt in the international market. Bulk of the solar salt is also used in ‘de-icing’ road due to severe snow in the industrialised countries. CAPZ desalination can recover up to 72% fresh water as well as 4.70% saturated sodium chloride brine simultaneously. Directly from seawater. Our current proposed plant in India will produce about 10,000 Mt of saturated Sodium chloride brine per day or 3150 Mt/day of high-quality salt along with 80,000 m3/day of fresh water from a seawater intake of 182,000 m3/day achieving zero liquid discharge (ZLD). We can also retrofit OARO system in our process to further increase water and salt production making it the most effective and economical and environmentally desalination technology in the world!

Tuesday, April 5, 2022

Why Carbon Recycling Technology (CRT) is the best option to decarbonise the planet?

There is no way CO2 can be hidden. It is the fundamental truth. World is trying to decarbonise for nearly 27 years since Kyoto protocol without success The CO2 level is now more than 50% above pre-industrial level. It is because no realistic steps were taken to decarbonise the fossil economy because the fossil lobby is in the forefront offering solutions such as CCS and CCUS by inventing various shades of Hydrogen such as blue, grey, black and pink! because Hydrogen is already widely used in oil and gas industries, and it is easier for them to use Hydrogen in the energy mix. But it emits significant amount of CO2 into the atmosphere. The word ‘Carbon capture’ guarantees the ’continuous emissions of CO2 and utility of fossil fuels’ whether such captured Carbon will be buried deep underground or converted into any other product. Even when converted into an industrial product one cannot remove the Carbon backbone and will continue to emit CO2 in various forms at various applications. For example, Methanol can be synthesised using CO2 emission and Hydrogen. But Methanol on combustion will release CO2 back into the atmosphere. Injecting CO2 into aquifers will cause further acidification of the ocean damaging coral reefs and marine species. Injection of CO2 into existing oil wells to enhance ‘oil recovery’ is in fact an indirect method of Carbon recycling. Renewable energy is certainly one option, but it will not be enough to meet the growing demand of the world. Battery is an energy storage device. It is useful in its traditional ways, where there is a stop gap arrangement to store energy temporarily, especially with intermittent renewable energy sources. But it cannot be an energy solution no matter how sophisticated the technology is. World needs an uninterrupted continues and clean electricity (24 x 7) with absolutely no emissions including Oxides of Carbon, Nitrogen, Sulphur and Hydrogen. Many companies are betting on Hydrogen as an alternative to fossil fuel. But Hydrogen is an energy carrier and cannot be a fuel itself; but it is very useful to decarbonise the CO2 emissions by converting CO2 into a hydrocarbon and recycling it internally within the system. Governments should offer subsidy to Carbon negative fuels because it is the only way CO2 level in the atmosphere can be stabilised. If Governments around the world fail to act now then ‘Mother Nature’ will act with catastrophic consequences such as heavy snow, bushfires, floods, draughts, pandemics and wars. Many scientists now started believing pandemic may be a direct cause of global warming and climate change. Let us hope this may not be the case.