INST scientists come up with a prototype for water splitting with sunlight

Scientists at the Institute of Nano Science and Technology (INST), Mohali, an autonomous institute under the Department of Science and Technology, Government of India, have developed a prototype reactor which produces hydrogen under natural sunlight, through “photocatalytic water splitting”, according to a government press release. 

The reactor designed by Dr. Kamalakannan Kailasam and his team, including Prof. Ashok K Ganguli, Dr.Vivek Bagchi, Dr.Sanyasinaidu Boddu, Dr. Prakash P N & Dr. Menaka Jha from the Institute of Nano Science and Technology (INST), can produce 6.1 litres of hydrogen in 8 hours. The researchers have used an earth-abundant chemical called carbon nitrides as a catalyst for the purpose. 

The process had been attempted many times by many researchers using complex metal oxide/nitride/sulphide based heterogeneous systems but was very difficult to reproduce in large quantities. 

                                                Image Credit: authors of the paper 

The INST team employed the low-cost organic semiconductor in carbon nitrides which can be prepared using cheaper precursors like urea and melamine at ease in a kilogram scale. When the sunlight falls on this semiconductor, electrons, and holes are generated. The electrons reduced the protons to produce hydrogen, and holes are consumed by some chemical agents called sacrificial agents. If the holes are not consumed, then they will recombine with the electrons. This work is supported by the DST Nano Mission NATDP project, and the related article has been published in the ‘Journal of Cleaner Production’ recently, and the team is in the process of obtaining a patent for the technology. 

The INST team has been working in this area of photocatalytic water splitting to generate hydrogen for quite some time now. “The energy crisis and ever-threatening climate crisis urged us to work on this promising way of hydrogen production through photocatalytic water splitting. The stability and chemical flexibility of having different organic groups in carbon nitrides triggered us to work on these cost-effective organic semiconductor materials for sustainable hydrogen production,” added Dr. Kamalakannan. 

The INST team started from the lab-scale process to the bulk scale of developing the photocatalyst and hydrogen production through a large prototype reactor. The reactor is about 1 metre square, and the photocatalyst was coated in the form of panels where water flow is maintained. Upon natural sunlight irradiation, hydrogen production occurs and is quantified through gas chromatography. The team is in the process of optimising the hydrogen production with effective sunlight hours in addition to the purity of the hydrogen, moisture traps, and gas separation membranes so as to hyphenate with the fuel cells.   

 

ARCI scientist wants to produce hydrogen by adding methanol to the mix

Dr R Balaji, a scientist with the International Centre for Advanced Research in Powder Metallurgy and New Materials (ARCI), is working on a concept that will lead to production of hydrogen at around $ 3 a kg.

                                                      Dr Rengarajan Balaji, Senior Scientist, ARCI

His method is to simply add methanol to water in an electrolyser.

Water splits into hydrogen and oxygen: H2O => H2 + O2

Methanol mixes with water to produce hydrogen:  CH3OH + H2O => 3H2 + CO2

By doing this, the requirement of electricity will come down to a third of water electrolysis.

But where will the methanol come from?

Dr Balaji points to a recent development at BHEL. The public sector company recently announced that it had set up a 0.25 tons-per-day pilot plant that uses 'fluidized bed gasification' technology to produce syngas from the high-ash Indian coals, and then convert the syngas to methanol. BHEL's technology's uniqueness is the ability to handle high ash and the heat required to melt the ash.

Dr Balaji has benchmarked methanol cost at the landed price of imported methanol at Mumbai port, at Rs 23 a litre and has arrived at hydrogen cost of $3-4 a kg, but BHEL's coal-derived methanol should be much cheaper. This route may make hydrogen at $ 2 per kg feasible.

GE is ready with a gas turbine that can run on hydrogen

 GE has done its part in the hydrogen economy game. It is ready with a gas turbine that can be powered by hydrogen, reports Business Line newspaper.

GE has developed advanced premixed combustors to run gas turbines. Combustors are basically fuel injectors with walls to contain the flame. Through a delicate balancing of fuel and oxygen, the flame is stabilized so that the gas turbine can accelerate easily and perform optimally. Combustors then feed the high pressure, hot gas stream in turbine components and blades spin to generate power.

                                           Image credit: GE

GE’s DLN family (DLN 2/2.6/2.6+/2.6e) (Dry-Low NOx) of combustion systems enables GE’s F-and H-class gas turbines to reduce NOx emissions while enabling high plant efficiency plus extending outage intervals.

Premixed combustors at play

GE collaborated with the US Department of Energy in their Advanced Hydrogen Gas Turbine Program from 2005-2015 to develop a low nitrogen oxide-hydrogen combustion system that significantly increased the efficiency of its gas turbines.

In GE’s advanced premixed combustors, hydrogen and air are mixed in an optimal ratio and burned to get more heat energy. Emissions reduce because the fuel is premixed well, and the combustor releases thermal energy with less nitrogen oxides.

In this process, nitrogen oxide released is merely 25 ppm, well within World Bank emission norms and those specified under individual country regulations.

Further, these 3D-printed advanced premix combustors have small bundles of tubes for even better fuel mixing and further reduction of emissions. GE’s experience in developing gas turbines for airplanes helped them develop this technology.

GE’s latest gas turbine, the 9HA 0.2, uses precision-engineered, advanced premix combustors that have the capability to burn up to 50% hydrogen by volume blended with natural gas with technology pathway to 100%. The net efficiency level of a power plant powered by 9HA.02 gas turbine in a combined-cycle mode is more than 64%, meaning they can convert 64% of a drop of fuel into electricity. In comparison, the average car engine only manages 40% efficiency.

The efficiency gains help reduce fuel costs and carbon dioxide (CO2) emissions. In fact, GE holds two world Records for gas power plant efficiency. It accounts for a third of the world’s installed power base, with more than 10,000 gas and steam turbine generating units, representing more than 1,000,000 MW of installed capacity in 120 countries.

In the Indian context, GE’s new generation of combustion systems, better known as advanced premix combustors, enable hydrogen to burn at higher temperatures, helping produce highly efficient energy – electricity at around Rs 4 per kWhr, with low emissions.

Hydrogen in the wind-solar mix

In India, solar power is abundant and peaks between 12 noon and 2 PM. The excess power generated in the afternoon can’t be sent to the electricity grid, but renewable energy farm owners can use it to generate hydrogen from water. In turn, this hydrogen can be stored in batteries as fuel and used to generate power from gas turbines when the sun sets, producing power round the clock.

GE, a world leader in gas turbine fuel flexibility, including more than 75 gas turbines that have (or continue to) operate on fuels that contain hydrogen. This fleet has accumulated more than 6 million operating hours and produced more than 450 Terawatt-hours of electricity.

IIT Madras professor wants to produce hydrogen by reacting sea water with aluminium

Prof Satyanarayanan Chakravarthy of the Indian Institute of Technology, Madras, has designed a process for producing hydrogen by reacting sea water with aluminium. 

As sea water (any water) reacts with aluminium (any metal), the oxygen joins with the metal to form oxide (alumina), liberating hydrogen. There are two problems, though. First, the oxygen forms an oxide layer, preventing further reactions. Second, aluminium (any metal) costs money, making the process economically unviable.

Chakravarthy has tackled the two problems this way. His design uses aluminium nano particles to counter the first problem. As for the second, the process recovers aluminium from alumina. 

                                                        Dr Satya Chakravarthy

Now, recovery of aluminium from alumina is an energy-consuming process, for two reasons. It requires energy to operate and the electrolysers use electrodes that are consumed away in the process.

Once again, Chakravarthy's system has answers. As for energy, there is some within the system. If you react the liberated the hydrogen with the atmospheric carbon dioxide with an aim to make methanol, that reaction produces heat which can be tapped. And for electrodes, Chakravarthy has come up with non-consumable electrodes--titanium diboride cathode, nickel ferrite anode, immersed in an electrolytic bath of molten cryolite.

Chakravarthy says the process is both technically and economically feasible. It is being worked into a pilot through a start-up that Chakravarthy mentors, called X2Fuels Energy. The start-up is looking for funding for the pilot and beyond.

The following visuals explain the process better.

"Experimental investigations of novel catalytic reactors, pointing out their greater heat transfer properties, which is mainly appealing for the design of small-scale methanol synthesis processes have been established. Significant catalytic research has been conducted in IIT Madras, which has provided a fundamental understanding of the different process conditions and the behaviuor of different catalysts," says Chakravarthy. "Our next step is towards a pilot scale continuous plant, with systematic scale-up road-map."

Biomass route produces the cheapest, cleanest hydrogen, says Preetam Singh, Founder-CEO of Biezel Green

Dr Preetam Singh is the founder and CEO of Biezel Green Energy, a company based in Varanasi, Uttar Pradesh, India, which produces hydrogen from biomass, using its proprietory ‘thermally accelerated anaerobic digestion (TAD) reactor. Prof Singh teaches at the Indian Institute of Technology, Banares. Earlier, he worked with Prof John Goodenough, who won the Nobel Prize for Chemistry in 2019, for his invention of Lithium-ion battery technology. 

Dr Singh is convinced that the best way to produce hydrogen, at least in India, is through the biomass route. Biezel Green’s process produces a bouquet of by-products, if you price which you can practically cost green hydrogen at zero. ‘Zero cost hydrogen’ is Dr Singh’s pitch to the world. 

In this interview to R S Sumedh of Hydrogenindianews, Dr Singh explains the science and commerce behind his venture. 

 

1. What is your process for producing hydrogen? What is it called and how does it work? What are the products that you get out of the process? 

 We have developed a novel fractionation process to produce bio-fuels from agro and forestry waste. Our process is similar to process occurred inside earth crust that convert fossils into useful fuels. Our process is a temperature programmed reaction system where temperature and pressure of reactant or bio-mass is varied inside an electrically controlled system in accelerated manner that fractionize biomass into majority of hydrogen, methane, CO2 , bio-coal and traces of other heavy hydtocarbons. We named our process TAD; Thermally accelerated Anaerobic Digestion. The trademark process convert bio-mass into 3-4% hydrogen, 14-17 methane, 28-30% biocoal, 40-42% CO2 and 1-2% bio-tar by weight. As such, the exhaust, we produce after CO2 cleaning contains 75-80% hydrogen and 20-25 methane:  a very high hydrogen containing biogas or natural gas. We have developed TAD reactors that have capability of 1500-2000 kg biomass processing in single operation of 36h. The smokeless bio-coal we produced have gross calorific value (GCV) greater than 6500-8000 Kcal/g depending on the biomass we use. 

2. What is the uniqueness of your technology? 

To be precise, the uniqueness of our technology is the control of temperature and pressure inside reactor to provide necessary activation energy for breaking of C-O, C-H chemical bonding necessary for fractionation. In general, , H-O-H bond breaks at 3600C for water, and using electrolysis to produce water, you will need almost 77 kW energy to produce 1 kg of hydrogen. However one kg hydrogen contains approximately 38 kW of energy equivalence. Theoretically H-O-H bond is strongest bond to break,that is why water is worst source to produce hydrogen. Any process that will use water as source to produce hydrogen will not be cost effective at all. However C-H bonds are much weaker than H-O-H bond, that is why organic biomass is much suitable source to produce hydrogen. 

3. Can you provide a brief cost-sheet to arrive at the price of 1 kg of Hydrogen?  

From 1 kg of biomass, we produce around 35-40 grams of hydrogen, 140-170g of methane, 280-300 g of bio-coal having gross calorific value greater than 7000 kcal/g. For a typical operation of 1500 kg biomass we approximately use 900 kilowatt (unit)  of energy and we produce around 60 Kg hydrogen, 250 Kg methane or natural gas, 400 Kg Bio-coal. 

250 kg methane has 60kg equivalence of hydrogen energy, and 400kg bio-coal having GCV 7000 Kcal/g has energy equivalence of 60 kg hydrogen. So in turn we use 900 kW of energy to produce 180 Kg of hydrogen equivalence energy. So 5 kW energy is sufficient to produce 1 kg of hydrogen equivalence. So in principle, providing sufficient price atleast Rs 5 per kg (7 USD cents) for agro and forestry waste, having covering operation, mentainance, separation and labourer charges, zero carbon footprint bio-hydrogen can be produce in less than 5 dollar by our process that is target of world hydrogen council and Japan to be achieved by 2050 , and we can provide that even by today. That is why we introduced Biezel Green Energy Pvt. Ltd. (https://biezelenergy.com/)to develop hydrogen production processing and commercialization. The total research establishment is property of Biezel Green Energy that has beared all R&D to indystrial scale pilot plant establishment through direct investment of funders. 

4. What is the exhaust from the TAD reactor? Is it CO2? If you are getting per kg of input, 40g of hydrogen, 170g of methane and 300g of bio coal, it adds up to 510g and you should get 410g of CO2? 
 

The exhaust from TAD reactor contains all: CO2, H2 ,  methane + other heavy hydrocarbon and carbon particulates and bio-tar. At lower temperature or in beginning majority of CO2 comes out as O-C-O or -C-O is having lowest energy and easiest to break. When CO2 flow become low, Then CH4 formation of extraction occur followed by dissociation of C-H bond in to Hydrogen formation. Along the line, formation of carbon particulates and bio-Tar also occurs in traces. That is why the direct exhaust of TAD reactors first goes through water cooled jacket for precipitation on bio-Tar, carbon particulates and moisture. Then exhaust travel through different carbon filters for complete capture of moisture and carbon particulates. Now the exhaust containing CO2, H2 and CH4 goes to online CO2 scrubber, and after CO2 scrubbing,  the exhaust comes out contains hydrogen (75-80)%,  Methane (19-24%) and traces of heavy hydrocarbon ( total~1%). In general we produce 3.5-4% Hydrogen, 14-17% methane, 28-30% bio-coal, 44% CO2. The 5-6% left out is moisture, carbon particulates and bio-Tar. 

 

5. Is it the CO2 you are going to convert into LNG?  

As explained earlier, after CO2 scrubbing or removal the exhaust contain hydrogen, methane and traces of heavy hydrocarbon. Methane and heavy hydrocarbon together known as natural gas (NG) ,and when compressed at 200 bar called CNG. Now to separate hydrogen and NG we use cryo-separation technology, where this mixture is cooled up to liquid nitrogen gas temperature (-200C). Now NG get liquefied and precipitated as LNG(liquefied natural gas). Because only hydrogen can not be liquefied at that temperature, it comes out in ultra high purity (UHP) stage. The cost of ultra purity hydrogen above Rs 2000 ($27.5) per kg currently. So our product after cryo-separation is UHP hydrogen and LNG stored in cryo vessels. We are not converting CO2 to LNG. CO2 is scrubbed at initial stage. Because CO2 coming out in our reactor is food for plant, because next season crop to grow we need that CO2 in atmosphere, other wise above carbon cycle will not complete. If we utilize this CO2 for other purpose then whole process will become carbon negative. Thus We are not doing any CO2 sequestration, neither it is needed. CO2 we produced in our pant is sellable as dry ice. 

6. How do the economics of L-CNG work out?  

For separation of our gas mixture (hydrogen and methane), we use cryo-separation developed and designed by us and we now get LNG and UHP hydrogen. LNG much easily portable fuel that is why GOI is now concentrated on LNG to expand CNG network in India because transportation of Natural gas as PNG through pipe line is very costly and limited to few regions. In China already 70% intercity transport in on LNG and L-CNG. We are also producing LNG or LBG along with UHP hydrogen. And then also we can provide unlimited UHP hydrogen to the world in below $ 5 per kg price because we are also producing LNG and bio-coal substantially. The total TAD exhaust economy favours us. In our process, when all exhaust comes out ,then biomass  converted in the form of bio-coal remained in the TAD reactor after cooling of the reactor, we take out the coal. 

 

7. What is your pitch to entrepreneurs who wish to partner with you?   

As the technology Partner, we are looking for financial partners who can provide  and manage funds for establishments of  TAD based Bio-fuel plants. The new or existing entrepreneur can work in propagation of the technology by providing financial security to technology spread and also can work in selling and bio-fuels such as hydrogen, CNG and BioCoal and CO2 and can also be engaged in raw materials procurement, transportation and processing. In turn they can get handsome credit in profit. Currently we are offering  50% profit for our financial partner in Joint Ventures. For technology spread and Bio-hydrogen plant establishments, we are forming joint ventures where a financial partner is liable for fund management for establishment of the plant and a technology partner , we own responsibility for establishment , operation and maintenance of the pants as well as to help in product selling. 

8. What is the minimum economical plant size? How much of biomass would be required for it? 

The Bio-fuel plant of 13-15 tons biomass capacity consisting of 24 TAD reactors containing  complete separation and dispensing unit for hydrogen, CNG, Bio-coal and CO2 will cost Rs 15 crore ($2 million). The minimum annual profit will be Rs 9-10 crore ($ 1.5 million) and investors will get 50% of the profit annually. In 30 years, investors will make at least Rs 150 core ($20 million).   

9. Broadly, what is the payback for the investment? 

Broad payback period for the investment is around three years.   

10. Is this venture a good fit for sugar mills, which have a lot of bagasse? How do the economics compare with electricity generation firing bagasse?   

Our output is at least 3 times better than electricity production through gasifiers. sugar mills can earn more than they earn from sugar making. Sugar mills can be considered as biofuel plants rather than sugar mills.