Boiler World Update

Written by 11:42 am General • One Comment

Hydrogen as fuel

The mere mention of Hydrogen conjures up a highly destructive image of a Hydrogen Bomb. However, when used correctly, thanks to advances in technology, hydrogen, when used as combustion fuel, can and will be instrumental in eliminating emissions and the related greenhouse effects, global warming, climate change, etc.

Why Hydrogen?

Emissions are part and parcel of fossil fuels, and with increased usage and demands, the level of pollutants across the globe has surpassed acceptable values.

So, what is the alternative that combusts without emitting Greenhouse Gases (GHG)?

–  Hydrogen.

Nevertheless, NOx emissions are not eliminated with hydrogen as fuel.

The current emissions in India are:

As can be seen from the above, while power and transportation contribute the most to pollution, industrial combustion also contributes significantly to pollution.

The adoption of green hydrogen in India can reduce greenhouse gas emissions to the extent of 50 million metric tonnes per year by 2030.

This is where we stand, and this is where we can make a difference by adopting cleaner fuels, aka hydrogen.

Types of hydrogen:

Green hydrogen, produced by electrolyzing water using electricity from renewable sources like wind or solar power, will be essential for decarbonizing energy-intensive industries such as air and maritime transport, steel production, and chemical manufacturing.

Generation-Production-Usage of Green Hydrogen

In the future, anticipated reductions in the costs of electrolyzers, along with technological advancements in renewable energy facilities and subsequent decreases in the cost per kWh produced, will make it feasible to develop large-scale green hydrogen production plants. Consequently, green hydrogen production could serve as a method for transforming, storing, and reusing energy generated from inherently irregular renewable sources like wind and solar power.

Hydrogen as a fuel faces several challenges:

1) Production Methods:

  • – Green Hydrogen: Producing hydrogen through electrolysis using renewable energy (green hydrogen) is energy-intensive and – requires significant infrastructure investment.
  • – Grey Hydrogen: Most current hydrogen production relies on fossil fuels (grey hydrogen), emitting CO2 in the process.

2) Storage and Transportation:

  • – Hydrogen has low energy density, making storage and transportation complex.
  • – Compressed gas or liquid hydrogen requires specialized containers and pipelines.

3) Safety Concerns:

  • – Hydrogen is highly flammable and can form explosive mixtures with air.
  • – Ensuring safe handling and storage is critical.

4) Costs:

  • – Green hydrogen production costs are high due to energy requirements.
  • – Infrastructure development (refuelling stations, pipelines) adds to costs.

5) Infrastructure Development:

  • – Building a hydrogen infrastructure (production, distribution, and refuelling) is a significant challenge.
  • – Retrofitting existing systems is costly.

6) End-Use Applications:

  • – Limited adoption in sectors like transportation, industry, and power generation.
  • – Developing viable applications is crucial.

7) Carbon Capture and Storage (CCS):

  • – Grey hydrogen can be coupled with CCS to reduce emissions.
  • – Scaling up CCS technology is essential.

Industrial Burners for Hydrogen:

Hydrogen burners and boilers are commonly used in refineries, chemical plants, and other facilities where hydrogen is produced in large quantities as a byproduct of various processes. They have no option but to harness hydrogen. However, in all these cases – since hydrogen is a byproduct of their process – relevant infrastructure, safety measures, etc. are already in place and do not call for capital investment, downtime, or retrofitting.

Industries that do not handle hydrogen in any manner will have to undertake substantial exercises and studies to change over to hydrogen as a fuel for combustion.

Safety for hydrogen boilers:

The attributes of hydrogen are very different from those of other fuels. Hydrogen has a much wider explosive range. In terms of gases as fuels, methane has a lower explosion limit (LEL) of 5% and an upper explosive limit (UEL) of 15%; thus, about 10% of the potential explosiveness range needs to be considered for safety. On the other hand, hydrogen has a LEL of 4% and a UEL of 70%. Thus, upgrading safety systems with additional safeguards is a must to prevent leakage and reduce the possibility of explosions.

Another safety consideration is the higher flame temperature of hydrogen. When comparing adiabatic flame temperature (ambient air with 1.3% moisture content), natural gas burns at around 1,925°C and hydrogen at close to 2,205°C. As the hydrogen flame temperature increases, thermal NOx emissions need to be addressed, and the MOC of the burner may need to be changed.

Water presence and density:

Hydrogen combustion produces water as a byproduct. Drains and drying measures must be considered before switching to hydrogen.

The water dew point of flue gas rises with the firing of hydrogen. Therefore, parts of the boiler in contact with flue gas are more prone to higher levels of condensation.

Numerous technical factors need to be accounted for and considered regarding the combustion of hydrogen and its comparison with fuels. Natural gas is denser than hydrogen and thus will require more space/area than natural gas. The size of storage vessels, the diameter of piping, the size of valves, etc. will have to be resized.

Being lighter, a lot more hydrogen will be required, as will larger pipes, larger metering stations, and some retrofitting. The hydrogen fuel supply system design should be able to accommodate the larger volume of gas needed at the desired pressure to deliver the required kCal.

CASE STUDY: Green Hydrogen Burners and Boilers Development

Company: RIELLO

Project Overview

Back in 2019, Riello launched an ambitious project to develop a range of burners and forced draught boilers (condensing boilers combined with burners) specifically developed to operate safely and highly efficiently with green hydrogen.

Testing and Results

The company carried out tests at the Combustion Research Centre in Angiari on a range of forced draught boiler condensing thermal units that are 100% fueled by hydrogen, obtaining excellent results both about the disappearance of carbon oxides in the flue gases (CO-CO2) and in terms of the very high energy efficiency achieved.

Hy4Heat Program Participation

In addition to its internal developments, Riello supplied six dual-stage low NOx burners powered 100% by hydrogen for the ‘Hy4Heat’ program a research project sponsored by the British government on the use of hydrogen in residential and commercial buildings and in gas appliances, to establish how this resource could be used in different communities.

Future Developments

Thanks to the significant results achieved, Riello will continue to invest in 100% hydrogen-powered burners, to reach higher power output, and to be used in experimental applications with commercial and industrial partners.

Outlook

Riello is ready to embrace the challenge posed by the energy transition, accompanying customers through this delicate phase through the research and development of solutions that can satisfy a wide range of application requirements. This is an urgent commitment that the hard-to-abate industrial and process sectors must make, and for which there does not exist just one, single path to be followed. Riello believes that it is essential to offer a portfolio of different technologies that can meet the specific needs of industrial processes, which differ so widely from one another. As such, energy efficiency, the circular economy, green fuels (hydrogen and biofuels), and electrification all represent complementary elements of a joint, integrated action plan that will help to reduce emissions in both the short and medium term.

The Government’s Initiatives & the Future:

India currently produces 6.5 million metric tons per annum (MMTPA) of hydrogen, predominantly for use in crude oil refineries and fertilizer production. Most of the country’s current hydrogen supply is grey hydrogen, produced from fossil fuels in a process that emits CO gas. India aims to produce 5 MMT per annum of green hydrogen by 2030, an additional 125 GW23 of renewable energy capacity is expected.

The targets forecast that the country will be able to avoid emitting nearly 50 MMT of CO2 into the atmosphere.

The current status of Green Hydrogen adoption in the country is as follows:

A) GAIL Constrained has propelled India’s first venture to mix hydrogen into the City Gas Dissemination grid. At the City Gas Station of Avantika Gas Limited (AGL) in Indore, Madhya Pradesh, 2% hydrogen by volume is being blended into the CNG network, and 5% hydrogen by volume is mixed into the PNG network.

B) NTPC Restricted has begun mixing up to 8% (vol/vol) Green Hydrogen into the PNG organized at NTPC Kawas Township, Surat, Gujarat, starting in January 2023.

C) Additionally, other PSUs have undertaken various projects, including:

  1. NTPC has conveyed hydrogen-based Fuel-Cell Electric Vehicle (FCEV) buses in Leh.
  2. NTPC has too conveyed hydrogen-based Fuel-Cell Electric Vehicle (FCEV) buses in More noteworthy Noida.
  3. Oil India Limited has developed a 60 kW hydrogen fuel cell bus that combines an electric drive with a fuel cell.
  4. Indian Oil has established demonstration pilot plants for producing green hydrogen through water electrolysis using solar power, biomass oxy-steam gasification, and CBG reforming to refuel 15 hydrogen fuel cell buses.

India’s commitment to achieve net zero emissions by 2070:

  1. India will get its non-fossil energy capacity to 500 gigawatts (GW) by 2030
  2. India will meet 50 percent of its energy requirements from renewable energy by 2030
  3. India will reduce the total projected carbon emissions by one billion tonnes from now on till 2030
  4. By 2030, India aims to reduce the carbon intensity of its economy by at least 45 percent.
  5. So, by the year 2070, India will achieve the target of Net Zero

Conclusion:

Though industrial combustion burners do not contribute much to GHG, in terms of long-term planning, recurring cost savings, and a cleaner future, the time has come to start considering and exploring the feasibility of switching over to Hydrogen Fired burners and discontinuing usage of Fossil fuels.

Disclaimer:

This article is a pure and simple compilation of various Articles, New snippets, Announcements, intentions, Intents, etc. as expressed across the globe and in India regarding the use of Hydrogen as Green Fuel and in no way purports to be a Research Finding, Narration of firsthand experience, scientific insight, etc. The information provided is prepared on the basis of information collected from various sources related to Hydrogen and sources publicly available on a best-effort basis and based on current status. These data and information are published for informative and indicative purposes only All content is provided “as is” without any warranty of any kind as to the completeness, accuracy, fitness for any particular purpose, or any use of results based on this information. The reader, in its capacity as a professional individual or entity, shall be responsible for seeking to verify the accurate and relevant information needed for its own assessment and decision and shall be responsible for using the document or any part of it for any purpose other than that for which it is intended. The author hereby expressly disclaims all warranties and representations, whether expressly or implied, including without limitation, warranties or representations of merchantability or fitness for a particular purpose and assumes no liability for the content of external links to other websites.

Special thanks to Riello S.p.A., Italy, for granting access to their experience, trials, prototypes, guidance, proofing, and technical data on the subject.

Author:

Mr Rajesh Pathak

General Manager – Business Development

Suntec Energy Systems