Production of Caustic soda by desalination of sea water with fresh water as by-product

There is a great deal of misconception about desalination of seawater and the word ‘desalination’ is taken literally as a method of separating fresh water from seawater but not the separation of salt from seawater. The main focus here is only about recovery of fresh water from seawater or from any saline water sources but not salt. In fact separation of salt from seawater is also known as desalination or desalting. The reason for this misconception is because fresh drinking water is in demand and people are concerned only with fresh water and not the salt. There is a huge demand for fresh drinking water all over the world. Increasing population, large scale usage of fresh water by industries, pollution of fresh water by domestic and industrial effluents, failure of monsoon or seasonal rains due to climate change are some of the factors that contributes to water shortage. There is also a demand for water by agriculture industry both in terms of quality and quantity. Bulk of the ground water is used as a main source of fresh water by agriculture industries in many countries. But sea water also contains number of minerals or salts which have greater economic and commercial value. In terms of quantity their presence is small, only 3.5% and the rest 96.5% is fresh water. For example Chemical industries such as Caustic soda and Soda ash plants use salt as their raw material. But they also use demineralized water to dissolve salt to produce brine which is their feed stock. Therefore Chemical plants are the largest users of seawater in terms of salt as well as fresh water. Power plants mainly located on seashore also use large quantity of demineralized or desalinated water for boilers and for cooling towers. Sea is now becoming a great source of fresh water as the inland water supply is becoming scarcer due to dwindling water table by drought or flooding by too much rains, pollution by industries etc. In earlier days seawater was the only source of common salt known as Sodium chloride produced by solar evaporation. Bulk of the salt is till used by this method. Therefore it is logical to locate a chemical plant and a power plant side by side so that seawater can be utilized efficiently. CEWT (Australian company) has developed a new desalination technology called ‘CAPZ desalination technology’ that can generate fresh water as well as Sodium chloride brine simultaneously which is suitable for Caustic soda/Soda ash production. They can integrate such a facility with a skid mounted Chlorine plant of smaller capacities. This plant can generate large volume of drinking water (WHO standard) as a by-product that can be supplied to municipalities and agriculture industries. Locating large scale solar salt pans near such a facility will be a problem because it requires a huge area of arid land with good wind velocity and it takes nearly a year to harvest the salt. Using CAPZ desalination technology one can generate saturated Sodium chloride brine of 315 gpl concentration as well as fresh drinking water directly from seawater. The brine is purified to meet the specifications required by membrane Electrolysis for the production of Caustic Soda. The same brine can also be used for the production of Soda ash using Solvay process. It is no longer necessary to produce brine from solar salt. Solar salt requires vast area of arid land with good wind velocity and least rain fall and large manual labour force to work under harsh conditions; it is a very slow process and takes almost a year to harvest the salt, which is full of impurities and requires elaborate purification process during the production of Caustic Soda. Such purification process generates huge volume of solid waste for disposal. Chlor-alkali industry is one of the most polluting industries in the world. In fact these impurities can be converted into more value added products such as recovery of Magnesium metal or recover of Potassium salts. CAPZ technology is developing a ZLD (zero liquid discharge) desalination process where the effluent containing the above impurities such as Calcium, Magnesium and Sulphates are converted into value added products. By recovering more such salts from seawater one can recover additional fresh water. Therefore desalination of sea water is now emerging as an integral part of Chlor-alkali industry. By such integration Chlor-alkali can become a major player is meeting fresh drinking water of a nation. By careful integration and co-location of a desalination plant, Caustic soda plant, Food and pharmaceutical grade salt plant and a power plant on a sea shore will be a win situation for everybody involved. Let us take a specific case study of setting up a Caustic soda plant, a captive power plant and a desalination facility. A typical skid mounted Chlorine plant will have the following configuration: Capacity of Caustic Soda: 50.7 Mt/day (100% basis) Capacity of Chlorine : 45.00 Mt/day (100% basis) Hydrogen production : 14,800m3/day (100% basis) A typical usage of Vacuum salt for such skid mounted Chlorine plant will be about 76.50 Mt/day with a power consumption of 2.29 Mwhr/Mt of NaOH (100%). A captive power plant of capacity 200Mw will be able to supply necessary power for both Desalination facility as well as Caustic soda plant. The CAPZ desalination facility can supply a saturated sodium chloride brine (315gpl concentration) 245 Mt/day and 9122 m3/day of fresh drinking water from the desalination plant. This water can be used for boiler feed in the power plant. Surplus water can be supplied as drinking water meeting WHO specifications.

The Hydrogen gas the by-product from caustic soda plant with capacity of 14,800 m3/day can be used to generate clean power using a Fuel cell. The power generated from Fuel cell will be about 20 Mwhr/day that can be supplemented for the Caustic soda production thereby reducing the power consumption from 2.29Mwhr to 1.46 Mwhr/Mt of NaOH (100%) By careful integration of a large (ZLD) desalination facility with caustic soda plant and power plant it will be possible in future to generate a clean energy using Hydrogen, a by-product of Caustic soda plant and solar thermal plant to produce chemicals in a clean and environmentally sustainable manner. For further information on CAPZ technology, please contact ahilan@clean-energy-water-tech.com.

Fuelcell can become a commercial reality

We currently generate electric city from heat, obtained by combustion of fossil fuel such as coal, oil and gas. But such combustion generates not only heat but also greenhouse gases such as Carbon dioxide and oxides of Nirogen.The only alternative to generate power without any greenhouse gas emission is to use a fuel with zero carbon. However, oxides of Nitrogen will still be an issue as long as we use air for combustion because atmospheric air contains almost 79% Nitrogen and 21% oxygen. Therefore it becomes necessary to use an alternative fuel as well as an alternative power generation technology in the future to mitigate greenhouse problems. Hydrogen is an ideal fuel to mitigate greenhouse gases because combustion of Hydrogen with oxygen from air generates only water that is recyclable. Combining Hydrogen with Oxygen using Fuel cell, an electrochemical device is certainly an elegant solution to address greenhouse problems. But why Hydrogen and Fuel cell are not commonly available? Hydrogen is not available freely even though it is abundantly available in nature. It is available as a compound such as water (H2O) or Methane (CH4) and Ammonia (NH3). First we have to isolate Hydrogen from this compound as free Hydrogen and then store it under pressure. Hydrogen can easily form an explosive mixture with Oxygen and it requires careful handling. Moreover it is a very light gas and can easily escape. It has to be compressed and stored under high pressure. Generation of pure Hydrogen from water using Electrolysis requires more electricity that it can generate. However, Hydrogen cost can be reduced using renewable energy source such as solar thermal. The solar thermal can also supply thermal energy for decomposing Ammonia into Hydrogen and Nitrogen as well as to supply endothermic heat necessary for steam reformation of natural gas into Hydrogen. Onsite Hydrogen generation using solar thermal using either electricity or heat can currently become a commercial reality. Hydrogen generation at higher temperatures such as Ammonia decomposition or steam reformation can be directly used in Fuel cell such as Phosphoric acid Fuel cell. Phosphoric acid fuel cell is a proven and tested commercial Fuel cell that is currently used for base load power generation. It is also used for CHP applications. Hydrogen generation using solar thermal and power generation using Fuel cell is already a commercial reality and also an elegant solution to mitigate greenhouse gases. Large scale deployment of Fuel cell and solar thermal will also reduce the cost of installations and running cost competing with fossil fuel.Fuecell technology has a potential to become a common solution for both power generation and transportation. While Government can encourage renewable energy by subsidizing PV solar panels and discourage fossil fuel by imposing carbon tax, they should give preference and higher tariff for power purchase from Solar thermal and Fuel cell power generators. This will encourage large scale deployment of Fuel cell as a potential base load power source.

Water Fuelcell-a panacea for energy problems?

Stanley Meyer, a freelance inventor from USA demonstrated a car that ran on water, according to an Equinox programme that was televised in 1995. Stane Meyer’s dune buggy ran 100 miles from 1 gallon of water. He claimed that water would be the fuel that could revolutionize the auto industry in America. However, his tragic death in 1998 brought the issue to a closure. Many individuals and institutions are still trying to replicate his invention at least partly and claiming success. He received a number of patents based on his inventions. He worked nearly 30 years on his invention before he began to work on a book titled, “With the Lord, there is a purpose” describing his “faith walk” with the Lord to fulfill end-time Prophecy. He continued with his speaking engagements throughout the world. However, such ‘free energy’ devices are still not getting the approval of the larger scientific community as well as Government agencies for some reasons or other. According to Stanley Meyer, “the law of Physics establishes a proven function based on ‘Pre-set’ conditions...change any of the conditions and the Law no longer applies….A new law emerges in the consciousness of physics. Why? Because atoms possess intelligence----Performing ‘what if’ logic function under different ‘preset’ conditions.” His claims were based on scientific principles and explanations. Based on his invention, a large number of ‘Electrolyzing devices’ appeared in the market. They supply DIY kits that can be fitted into a car to reduce Gasoline consumptions; but they do not entirely substitute Gasoline like Stanley Meyer demonstrated. There are still missing pieces of information or claims. He was able to demonstrate and claim “Hydrogen fracturing process to disassociate water molecules by way of voltage simulation, ionization of combustible gases by electron ejection and then preventing the water formation during thermal ignition releasing a thermal explosive energy beyond ‘normal gas burns’ levels under control state… and such an atomic energy process is environmentally safe”. He did not use ‘Heavy water’ called ‘Deuterium’ but normal water and controlled state and shown that the covalent bond of water can be broken using an electronic circuit using water as dielectric medium of a capacitor. It uses a high voltage but a low current and the process is instantaneous. It differs from the ‘Faraday’s law of electrolysis’ in a conventional sense. The scientific community seems to be a little more understanding with an open mind in recent times to such ‘free energy’ concepts and devices than in the past. ‘Resonance electrolysis’ has been reported by few institutions and individuals as an alternative to ‘conventional water electrolysis’ to reduce energy consumption. Decomposition of water into its molecules requires high temperature above 3000°C using a process known as ‘pyrolyis’ and a technique to separate the decomposed molecules from reunion for water formation. Prof. Mizuna of Hokkaido University of Japan and his coworkers demonstrated ‘Plasma Electrolysis’ by an experiment which showed an evolution of anomalous amount of Hydrogen and oxygen sometimes as much as 80 times more than normal Faraday’s electrolysis of gas generation. Though such reaction requires a very high temperature they could not successfully measure the reaction temperatures during the experiments. They used a Platinum anode and Tungsten cathode and a provision to separate Hydrogen and oxygen gases. They concluded at the end of the experiment that the input voltage and the current efficiency were critical parameters. On increasing the Voltage to several thousands, they said the current efficiency can exceed unity. The anomalous release of gases indicates that the electrolysis is not a normal electrolysis but beyond that. (Ref:Mizuno, T., T. Akimoto, and T. Ohmori. Confirmation of anomalous hydrogen generation by plasma electrolysis. in 4th Meeting of Japan CF Research Society. 2003. Iwate, Japan: Iwate University) In all these experiments the gases coming out of the system are not at high temperature but at normal room temperature. The chemistry of water molecule decomposition and plasma pyrolysis is not fully understood. After all ‘Cold fusion’ seems to be plausible under certain conditions and it may be a panacea for the world’s energy problems. When our energy requirement exceeds a limit due to a population explosion and industrialization then finding a solution becomes a daunting task. Mohandas Gandhi said: “There is enough for everybody’s need but not for everybody’s greed. Be the change what you wish to see in the world”.

How to generate your own Hydrogen?

It is amazing that highly combustible Hydrogen is a constituent of cool water. As long as it remains a part of a water molecule we are able to handle it easily. Water is always in a state of ionization with H+ and OH- ions in a dynamic equilibrium. The electrical conductivity of pure water which is completely free from any other ions is almost zero. In a solid polymer electrolyzer, which is the reverse of Fuel cell, water is decomposed into Hydrogen and Oxygen while passing a Direct current. Electrolyzer is an electrolytic cell similar to battery, containing an Anode, Cathode and Electrolyte. In a solid polymer Electrolyzer, the electrolyte is a polymer membrane. Water is decomposed as shown in the following reaction: At Anode of electrolyzer: H2O-------- 0.5 O2 + 2e + 2H† At Cathode of electrolyzer: 2H† + 2e ------ H2 The purity of water is critical in the above process of electrolysis. In conventional electrolysis, water with addition of potash lye (KOH) acts as an electrolyte. But in the above process there is no need for any addition of lye. Moreover, Hydrogen can be generated at high pressure so that further compression becomes easier. In cases of power generation using Fuel cell, the Hydrogen pressure from Electrolyzer is sufficiently high, obviating the usage of an additional compressor. The electrical conductivity of water increases as the concentration of dissolved salts increases. That is why the conductivity of seawater is much higher than your tapwater.But this salt can be removed by the process of desalination using ‘reverse osmosis’ systems. When you separate pure water and salt water using a semi permeable membrane there is natural tendency for pure water to pass across the membrane to pure water side. This process is called ‘Osmosis’. The process continues till the concentration of water on both side of the membrane becomes equal. Nature does not like disparities between strong and weak and always tend to make both equal. By reversing this principle of osmosis, we can separate salt water into pure water and highly concentrated salt water known as brine. This process is called ‘Reverse osmosis’. We will discuss about this process later. If your tap water is not very hard, say for example, total dissolved solids TDS is around 500ppm (Part per million), then the osmotic pressure is not high, which means you do not need to use a high pressure pump. Higher the TDS level, higher the osmotic pressure and higher the power consumption will be. You can install a reverse osmosis system based on your water analysis. You have to use a pure water with low electrical conductivity less than 1 micro Siemens/cm.The reverse osmosis system can be connected to your tap and store pure water while draining the salt water into the drain. You can use this pure water into an Electrolyzer to generate Hydrogen. The Hydrogen can be stored in a tank made up of Carbon composite materials that can withstand high pressure and approved by regulatory authorities. This article is only to understand how Hydrogen can be generated using your tap water. The actual implementation of the system requires knowledge and experience in installing such a system. But we will release an eBook, a step by step guide to set up your power generation system as well fuelling your Fuel cell car, using Hydrogen. An independent power generation and fuelling system using only solar power and water will soon become a commercial reality because, it is a clean and sustainable solution for all our energy problems. The PV solar industries are already expanding at a faster rate and solar Hydrogen will soon become an ultimate solution.

How to power your home and fuel your car with Hydrogen?

There is a general opinion that Hydrogen is dangerous or explosive; people are often reminded of Hindenburg accident or Hydrogen bombs. Hydrogen is as safe as Gasoline or Butane gas. It should be handled with care like any combustible material. We have used Hydrogen in industries for so many decades and transported by pipelines across thousands of kilometers; the methods and procedures of handling Hydrogen is well established. It is a very light, colorless and odorless gas and it can easily escape into the atmosphere. Hydrogenation of vegetable oils for production of certain Margarines is one of the classical industrial examples of Hydrogen usage. When 100m3 Hydrogen is compressed to 10,000psi pressure, it is reduced to just 0.163 m3 by vlume.That is how the Hydrogen storage space is reduced in passenger cars. This volume of gas can give a mileage of 652 miles using Fuel cell power. The only emission is just pure water vapor! No noise, no smoke and it is entirely a new experience driving a Hydrogen Fuel cell car. Powering your home with Hydrogen or fuelling your Fuel cell car is not very difficult. It is expensive compared to grid power for two simple reasons. Grid power is generated by power generation companies somewhere else using coal, oil or gas and transmitted across to millions of people.Therefore investment on power generation is shared by millions of people through their monthly energy bills. When you use the grid power, you do not pay any large sum except, a small deposit of few hundred dollars towards connection fee, and you pay your bills based on your monthly electricity usage. But when you try to generate your own power using a solar panel or Fuel cell then you have to make an investment fully upfront. Of course your bank can help financing the system. However, when you calculate the energy cost over the life period of 25 years, you can clearly see the value of such investment. The grid power cost will only increase and never decrease while your generation cost will decrease as the time passes. The future energy cost is likely to increase substantially due to various factors. You can export surplus power to the grid and your payback time will be reduced as the energy cost increases. The first step in powering your home is to calculate your power requirements accurately in terms of watt.hrs.How many appliances you will be using and how many hours you will using each of these appliances per day. Suppose you estimate 15,000 watt.hrs/day or 15kwhrs/day of power, and then a small Fuel cell consuming 1 Kg/day of Hydrogen or 30 kgs/month of Hydrogen will be sufficient to meet your power demands. Similarly you can calculate the amount of Hydrogen you will be using as a fuel for your Fuel cell car. For example if you will be driving your Fuel cell car for 1000 miles per month, then your Hydrogen requirement will be about 14 kgs/month. Your Hydrogen requirement per month for both power and car together will be 44 kgs only. Your total power requirement to generate the above Hydrogen will be 2464 kwhrs/month costing less than $250 per month for both power and fuel. Of course, you need to calculate other fixed costs on the investment. You can export your solar power at a higher tariff to the Government and import your power requirement from the grid during off-peak season at a lower tariff and generate Hydrogen and store it. You can generate your power as and when you need, and you are in complete control of your situation, even if there is a blackout due to grid failure!