Many people are predicting that with so much attention being paid to renewable energy, investment in fossil fuels will decline and eventually wane away as the world moves towards a clean energy future. However, there are also some who argue that natural gas has an important role to play in transitioning our society off of coal-fired power plants and into more sustainable sources of energy like wind and solar power. With all these different predictions about the future of natural gas, it can be difficult to know how we should invest now given its uncertain fate on the global stage.
The Current Climate State
LNG is one of the best ways to reduce the impact of climate change because it produces less carbon dioxide when burnt. When LNG replaces coal, the reduction in emissions is usually over 50%. The production of LNG also requires a lot less water than coal production, which has been a significant problem recently due to drought. LNG also does not produce sulfur dioxide and particulate matter, unlike coal.
There are other benefits for using LNG as well: it is cheaper than coal and it provides more energy per ton. For these reasons, climate experts and advocates suggest that we need to find a way to scale up natural gas usage.
Natural gas demand is increasing as a result of growing awareness about the environment and a desire for a clean energy transition. Countless countries have been demanding more gas as an ecologically cleaner energy source. It is generally considered that the demand for LNG will rise by 14% from 2020 to 2025. The bulk of this demand would come from Europe, followed by China, South Asia, and Southeast Asia as significant development areas.
In order to address these demands, it is critical that the LNG processes are as efficient and sustainable as possible. Heat exchangers, which perform essential heat-transfer functions in a variety of oil and gas procedures, are capable of supporting the reduction of emissions in LNG facilities to enable net zero.
Challenges of the LNG Process
LNG is a vital component of more sustainable energy and fuel supply; however, liquefaction and LNG transportation produce greenhouse gases. This is because the liquefication and regasification processes necessitate significant amounts of energy. This is partially due to the parasitic losses due to boil-off throughout storage and transportation. Greenhouse gases are also emitted by pure LNG or dual-fuel engines due to methane slips, however, they still offer a bigger reduction in overall emissions than conventional gasoline engines.
In addition to the problems surrounding environmental sustainability. there are also concerns over the regasification process and the distribution of LNG once it reaches land. For projects where land-based facilities are infeasible because of space or money, floating storage regasification units (FSRUs) offer a more economic, practical, and environmentally friendly alternative for the conversion of LNG to its gaseous state when being piped inland from offshore platforms. However, these units, like offshore oil and gas platforms, have very particular needs and are smaller in scale than land platforms.
Reduced Emissions through Heat Exchanger Developments
All steps in the LNG value chain rely on heat exchangers. Heat exchangers have evolved to meet the needs of the LNG industry, with improved efficiency, energy savings, ease of maintenance, and increasingly, modularity. Heat exchangers are required to withstand high pressure and resist large temperature spans. As such the equipment is often heavy and bulky. It can be difficult to find a suitable and efficient solution for liquefaction and regasification on FRSUs, where space is limited.
Meggitt’s Heatric division has developed printed circuit heat exchangers (PCHEs) to meet the unique demands of high-productivity, space-constrained platforms like FRSUs. The cooling efficiency of these designs is high, they include reduced pressure drop, high-pressure design and they save space and weight. PCHEs are capable of maintaining extremely close temperatures while also being very energy-efficient, allowing for more efficient thermal efficiencies throughout the LNG value chain. Heatric PCHEs are manufactured to be 85% smaller and lighter than previous technologies, providing significant space and building savings due to the lack of extra piping and equipment. It also reduces the overall weight impact on FRSUs, lowering fuel consumption and emissions savings.
Safety is also of the highest importance, as with any oil or gas offshore platform. Therefore, the equipment has to be highly durable. PCHEs are not susceptible to vibration and have no catastrophic failure modes. Diffusion bonding is a specialised solid-state joining technique. Heat exchangers made with this method are very durable, able to withstand temperature shocks and mechanical damage, ensuring the greatest safety levels while also optimizing system uptime.
LNG – Fuel for Greener Shipping
LNG is not only being used as a cleaner energy source in the climate change fight. The marine sector, in particular, is another key force propelling LNG demand. Shipping is the most important enabler of international trade and is under increasing pressure to minimize its environmental impact. LNG’s increased use as a cleaner fuel to power shipping has led it to be viewed, at least as an interim solution, as a better alternative. The shipping sector has traditionally used marine diesel oil (MDO) for power and propulsion. LNG is a more environment-friendly alternative to diesel since it produces 30 percent less carbon dioxide than typical diesel equivalents used in the industry. Additionally, ships that run on LNG emit almost no sulfur oxide.
A small number of vessels have made the switch to operate on LNG, with most having dual-fuel capacity, allowing them to change between MDO and LNG. The number of ships fuelled by LNG exclusively, on the other hand, is increasing at an accelerated rate and should rise as existing LNG infrastructure grows and cost becomes comparable to other fuels.
A push to reduce carbon emissions is partly motivated by an International Maritime Organisation-imposed deadline of reducing carbon emissions by half compared to 2008 levels by the year 2050. Several IMO regulations have already been implemented to limit several harmful pollutants in an effort to jumpstart the green revolution in international shipping. It is also being driven by consumer demands for a more environmentally friendly supply chain. Large shipping companies are aware that if they want a long-term chartering agreement with a major customer, they will be judged on the environmental friendliness of their ships. For example, Royal Dutch Shell plc and Australian mining firm BHP have for the past 18 months been offering long-term charters to shipowners who are willing to construct natural gas-fuelled tankers and bulk carriers.
For many years, bulk tankers that move LNG across the seas have used LNG. Although LNG storage tanks have been developed to minimize waste, a little quantity of LNG does revert back to gas while it is being transported, rather than losing it. BOG (boil-off gas) can be used as a fuel source for the engines or re-liquefied and returned to the LNG storage tank using specialist BOG reliquification systems. Some other LNG-powered vessels require a complete system including an LNG storage tank, an LNG processing system, and a control and safety system that transforms LNG into gas to power the ship. Including this equipment can seriously impact the space and weight efficiency of cargo ships. PCHEs are an essential component of both BOG reliquefication systems and FGSSs since they provide space and weight savings, making them an important part of meeting the emissions targets of LNG.
To give the market the best opportunity at optimizing impact through lowering emissions while demand growth is greatest, the LNG value chain requires optimized equipment and procedures at each stage. Gas prices are unpredictable and demand is anticipated to fluctuate for the immediate term in the United Kingdom for example, where a long, windless summer has prompted the start-up of coal plants to cover energy gaps caused by offshore wind. LNG remains the key transition fuel as the development of alternatives such as hydrogen matures and becomes economically viable. Meanwhile, the need is to maintain the growth in LNG applications as a key component of supplying the long-term energy mix required for worldwide carbon reduction. Otherwise, LNG could fall short of the mark.