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Challenges in renewables scaling

Author Pasi Leimu
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Dealing with labile biological materials is challenging. Even more challenging is scaling them to industrial-scale production. The secret of success in scale-up is step-wise development of the processing concept in cooperation with the client and project management focusing on techno-economic feasibility – the target is maximal yield for minimal costs and time.

In bioengineering, useful metabolic products are produced from biological material in aseptic or even sterile conditions. In the wider concept of bio and circular economy, the production utilizes naturally occurring renewable materials or recyclable materials in the form of waste or side streams of another operator and develops new innovative products with suitable technologies. Engineers must have experience of multiple materials – from virgin fiber used in the forest industry to recyclable textile fiber and waste fractions of different origins. Also utilization of side streams of food production, e.g., bakeries, meat production or dairies, such as whey, is targeted while not forgetting shelf life and traceability.

Understanding fundamentals
The challenges in today’s biotech and aseptic process field are finding suitably scaled technological solutions to produce homogenous and uniform products. Usually, the trials are carried out first at the laboratory scale and then the pilot scale before the industrial- level process is reasonable and justified. The labile biological materials make the fermentation and recovery processes a harder challenge than with chemical recovery. In these cases, the engineering is only an aid to regulation of biological processes and the micro-organisms command the center of attention. A clear understanding of microbial growth kinetics is necessary if a large-scale process is to be properly managed. Growth kinetics is treated differently for conventional batch processes than for continuous processes. Although several fermentations for metabolite production work well as processes at a laboratory scale, only a few processes have proved useful for practical application due to clearly fewer operational hours to be stable in a laboratory than in an industrial set up.

Also, attention should be paid to maintaining hygienic conditions on an industrial scale over a long period of time. Variation of industrial composition of substrates has to be anticipated as well.
In the wider concept of bio and circular economy, the production utilizes naturally occurring renewable materials, waste or side streams of another operator and develops new products with innovations and technologies. In these cases, the challenge is to optimize the feed and to get constant capacity. Also scaled, reasonably priced and agile technological solutions may turn out to be difficult to find for the production stream and quality fluctuations. New occupational and chemical safety issues may also arise with circular economy cases.

From challenges to solutions

A wide network of technology providers must be utilized with whom we can create tailor-made equipment and systems, if necessary. Technical consulting and engineering offices have expertise in a process and plant design as well as clean utility systems with applicable occupational safety features. A partner who is responsible for the product recovery and supporting utility and energy
systems is useful, while a plant owner usually focuses on the fermentation (cultivation of microorganisms) itself. Experts and consultants for circular economy projects should be competent in feasibility studies, capacity calculations and dimensioning of equipment as well as risk evaluations. Clean room air condition and ventilation, clean utilities and instrumentation would also be great additions to this toolkit. Finally, proper data acquisition and analysis are essential for calculating the effects of process variables on the final outcome in every development step. Process modelling is needed in order to optimise the process faster and more cost-effectively when targeting a well-functioning, industrial- level process. Understanding fundamentals behind the process is a key factor to successful scale-up. And a link between customer R&D and equipment manufacturers is needed for hands-on knowledge. A new scale-up process can be realised only with innovative, economic-technical solutions.

 

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Pasi Leimu

Project Manager
M.Sc.(Tech) 1990

Pasi Leimu has worked at Elomatic since 2001 and he is a very experienced project manager and process designer with good language skills. He has undertaken a wide range of different design, installation supervision and project start-up tasks. He has diverse experience in chemical-, metallurgical-, foodstuffs- and pharmaceutical industry projects with special expertise in consulting and ATEX directives.

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Hydrogen Fuel in Maritime Use

Author Mika Vuorinen
Posted on

The introduction of renewable energy is a major step to improve the local and global environment and bring down costs universally around all industries. The pursuit of green energy has caused a tidal wave of technologies to sprout with the aim of improved energy economy and utili­zation of low-emission energy carriers. The IMO 2050 strategy to reduce emis­sions is one driver towards lowered emissions in the maritime field and with innovative solutions introduced towards reaching this goal, there will be economical benefits in it in the long run. Though it is good to consider a variety of proposed alternative fuels that are increasing their foothold in the industry, a simpler path to the whole story can be found from the opposite end considering well-to-wake efficien­cy and emissions of a ship.

Well-to-wheels means an analysis of the whole fuel supply chain and is often a reference to fossil fuels but can as well be a reference to alternative fuels, energy carriers derived from either carbon-based or fully renew­able sources. The maritime take on this, well-to-wake analysis, consists of extraction of the fuel, possible refining of the fuel, transportation and bun­kering, and finally energy conversion to electrical or mechanical energy to power a vessel, thus producing a wake. Coming back from the wake, energy production for a vessel is the first place to increase the efficiency of the whole supply chain.

Application

Applications for higher fuel efficiency onboard a vessel can be reached by introducing new technology or by improving the existing equipment. In a general situation, fuel efficiency on a newbuilt ship is a sum of power production and transmission. Without going into too much detail, power production is the main engine and power is transferred as mechanical, heat and electric power. For fuel efficiency, the popular solution – from internal combustion engine to me­chanical power and with a generator to electric power – can be increased up to 50% but in practice is around 45%. Efficiency can be increased with additional equipment, for example a waste heat recovery system can increase the fuel efficiency of existing systems by roughly 10%. An internal combustion engine can be optimized for alternative and gaseous fuels, reaching similar fuel efficiencies.

Another fuel-based technology utilizing chemical energy is fuel cells, which convert the fuel gas directly into electricity and enable very high electrical efficiency. Different types of fuel cells allow high electrical efficien­cy, currently up to 60%, and are well suited in a maritime environment due to their good part load characteristics and minimum vibration and noise emissions. Fuel cells allow the possi­bility to reach reduced maintenance, modular and flexible design and water generation. The most attractive fuel cells for maritime use are PEMFC (polymer electrolyte membrane fuel cell) with high energy density and some maturity in the field, and SOFC (solid oxide fuel cell) with high tem­perature and even higher efficiency capabilities.

PEMFC has maturity in the mari­time field as a trial fuel cell, resulting in good initial outcomes for the system and has led to more comprehensive testing. The PEMFC system is very simple, and due to its low operating temperature of 70 °C, the mainte­nance cost is low. The latest modules have a size of up to 200 kW while being physically small, with 55% fuel efficiency. PEMFC will require highly pure hydrogen fuel onboard, which will demand a hydrogen storage or onboard system for reforming purified oxygen. PEMFC uses an expensive and trademarked Nafion membrane, which does not endure higher oper­ating temperatures. A lot of research is being concentrated in the devel­opment of high temperature PEMFC, which would overcome the high purity hydrogen demand and allow more flexible fuel utilization.

The SOFC system is a moderate­ly sized fuel cell, capable of highly efficient energy generation from hydrogen, natural gas and renewa­ble fuels with reduced emissions in comparison to internal combustion engines. The system requires high temperatures, 700 °C, to operate and can reach 60% fuel efficiency with a 60 kW unit. The current SOFC system’s major weaknesses are load cycling, a large and complex system and imma­turity of the technology, but its fuel flexibility and efficiency encourage further development for the system. The SOFC system does not require reforming the unit to utilize light hy­drocarbon fuels, such as methane and propane, or ammonia, but can utilize them as is. The high temperature in ship use allows combined heat and power use further increasing the fuel efficiency. Oxygen for both fuel cells is available from ambient air.

 

Maritime fuels

Maritime fuels can be divided into residual oils, or heavy fuel oils (HFO), and distillate oils with lower sulfur content (MGO, MDO). Low flashpoint fuels or more commonly alternative fuels are: Natural Gas (LNG), Ethane, LPG, Dimethyl Ether (DME), Methanol, Ethanol, Hydrogen, Ammonia. These fuels have relatively low greenhouse gas emissions and zero SOx emissions. In pursuing the lowest well-to-wake emissions, the production of a fuel, if not occurring in the nature, has a major effect on the supply chain emis­sions even if the operative emissions were to stay low.

Most alternative fuels are produced from hydrocarbons, but some have synthetization methods chemically (ammonia, DME utilizing hydrogen) or electrochemically (hydrogen through electrolysis). The debate about the most promising fuel for shipping purposes is intense and criticism toward all is a good habit to maintain. One thing to keep in mind is that the further processed a fuel is, the more efficiency is lost and well-to-wake emissions increase. For this article and its limited space it is good to concen­trate carefully and not to get further carried away, and to minimize both operative and production emissions; hydrogen with the potential for zero CO2 emissions will be chosen as the target of examination.

Hydrogen does not appear isolat­ed in nature. Hydrogen is generated in several different methods, most commonly by reforming hydrocarbons (natural gas) or by electrolysis through water. The origin of hydrogen can be referred to as the hydrogen rainbow, where different colors describe a vari­ety of possible production methods. The important ones are: grey hydrogen, which is produced from natural gas mainly by steam reforming; blue hydro­gen is the same as grey, but the CO2 is captured or re-used instead of released into the atmosphere; green hydrogen, which is produced with zero-carbon energy sources through electrolysis.

In 2020, the majority of hydrogen produced was grey hydrogen by 95% of all produced hydrogen. Hydrogen produced from natural gas needs three steps to reach the industrial standard of pure hydrogen, requiring, besides steam reforming, also steps through water gas shift and pressure swing adsorption, which are part of a standard hydrogen plant. This process reaches hydrogen purity for a PEM fuel cell. Hydrogen production with electrolysis is a method where water is breaking down molecularly to sepa­rate hydrogen and oxygen. Emissions of hydrogen production with electrol­ysis are tied to the used electricity.

Well-to-wake emissions for analysis include natural gas recovery, trans­portation, refinement, storage and bunkering. As combined in Figure 2, the production method for hydrogen from natural gas results in well-to-wake greenhouse gas emissions even larger than MGO and HFO when uti­lized in a modern four-stroke engine. The emissions from electricity used as a reference is the average Finnish elec­tricity grid in 2020. With excess green electricity, the emissions for hydrogen production can be brought down to far lower emissions.

 

 

Hydrogen (in maritime business)

 

Hydrogen in maritime business brings potential for green energy but there are challenges in its utilization. As a low flashpoint fuel, risk of fire must be minimized and double-walled piping in a dedicated, well-ventilated trunk should be included. Even with heavy precautions with the fuel, it has been concluded that small hydrogen leaks are often overshadowed by the pres­ence of air currents from ventilation, where the currents serve to disperse leaked hydrogen quickly reducing any associated fire hazard greatly. Storing hydrogen on the upper deck lowers the risk of fire in case of a leakage, as any leaking hydrogen rapidly moves up and away from potential ignition sources due to its light weight. On a ship, hydrogen storage must be well-ventilated and controlled with dedicated leak detection equipment.

The major challenge for hydrogen as a bunker fuel is the energy density. While having a high energy density by weight, hydrogen has very poor energy density by volume, forcing the bunker fuel to be either compressed up to 700 bar or liquefied. Liquefied hydrogen is stored at a low temper­ature of -253 °C. The liquefaction process efficiency is about 70%, while compressed hydrogen can reach 90%.

Figure 3 shows storage density of hy­drogen as liquefied hydrogen LH2 and compressed hydrogen cH2 of 450 bar with other alternative maritime fuels.

Hydrogen storage is a challeng­ing matter due to the size of hydro­gen molecules, which are tiny and can diffuse through many materials considered airtight or impermeable to other gases. The diffusion rate of hy­drogen increases with the tank pres­sure, close to 500 bar the rate nears 1% of cH2 per day. There are challenges with LH2 at bunkering and insulation due to its extreme temperature, and with poor liquefaction efficiency the compressed option is often more a viable option especially in smaller units in decentralized production, as pressurization for cH2 is simpler and more efficient than liquefaction.

Summary

Overall efficiency in shipping can be improved and emissions reduced considerably, but this process must be done carefully considering many angles. Operative emissions can be brought down with different fuel options, but well-to-wake emission and efficiency should be considered, and green alternatives prioritized in the production of alternative fuels. Further study about which fuels and power production to utilize in differ­ent shipping situations from ferries to container vessels is to be expected, as a comprehensive solution to improve shipping is not yet in sight.

Mika Vuorinen

Senior Design Engineer
(M.Sc. Mechanical Engineering)

Mika’s background is naval architecture
from University studies and
has 2 years of experience in project
work. His thesis covers hydrogen
economy and fuel cells in maritime
industry and has been working with
energy and machinery solutions for
ship conceptual projects with implication
of industry standard and
novel technologies. Mika has also
experience in ship general arrangement
and port operations. He has
worked as part of marine Life Cycle
solutions unit in Espoo since 2019.

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Stopping offshore lifting

Authors Heikki Välitalo, Ted Bergman
Posted on

Offshore constructions are in new growth where the traditional oil & gas foundation applications are now expanded to the energy industry. The global warming is abated in many ways, the oil & gas industry is facing seawater level changes and improvements and more focus towards gas production. The worlds need for rapid increase of renewable energy turns especially wind farm applications to offshore growth. With growing offshore wind farms different types of energy handling stations as offshore platforms and islands are needed for use as substations, HVDC and hydrogen production. The knowledge from years of experience in the traditional offshore sector have been packaged to a patent pending application enabling solid and cost efficient solution with
minimal environmental impact and total removal after end of use.

The new concept is aimed for construction in shallow waters. In these cases traditional method have been to build rock island which have high costs and environmental impact. After the settlement time, installation of the topsides equipment starts. This can be replaced with a floatable steel island which after towage to offshore location is lowered and self-piled to seabed eliminating major parts of offshore construction. From construction point of view offshore lifting operations can be minimized lowering costs
and risks. The steel island withstands harsh conditions, such as ice, and do not need protection barrier repairs after each winter.

The floatable feature is designed so that on-shore construction can be done in various conditions. Even a sand shore can be used or then construct it in a ship yard dependent of customer demands. After construction the steel island with already onshore installed topsides is floated and towed to site. This can be done even to very shallow waters. Floatable Steel island provides a solution to shallow water field locations near shoreline where the traditional offshore lift vessels cannot operate. From asset risk management point of view the island can be refloated and relocated. From environmental perspective at end of use the artificial island is simply refloated and brought to a location where the steel can be scrapped for reuse.

For whom is this to consider? Just about any topside construction can be applied. If you have a project independent it’s a foundation for wind mill, wind farm substation, hydrogen production, oil & gas field development for drilling rig, processing island or accommodation quarters. You may be looking into service hubs or just as a monopile for ice protection to your harbor or perhaps you need a platform for vessel surveys with independent drones. In any case you will get environmental and financial
benefits with a solution that do not need typical offshore construction such a lifting, dredging, hammering. The application is suitable from dense to soft sea bottoms where you might have difficulties of finding other suitable methods.

Heikki Välitalo

Project Director for Offshore

Heikki Välitalo joined Elomatic in 2019 as Project Director for Offshore Projects. His professional experience dates back to 1980’s and covers design, sales, project management in offshore oil & gas field development projects, as well in platforms / drilling rigs related projects.

Ted Bergman

M.Sc. (Chem. Eng)

Ted Bergman joined Elomatic in 2019 as Vice-President with a focus on developing international business. His professional experience dates back to 1995 and covers sales, design and commissioning tasks in e.g. the power industry, pulp & paper industry, and process industry.

Intelligent Engineering

Latest post

20/09/2022

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Kirjoittanut By Elomatic Oy

Vaasan Sähkö will have a plant built at the Pått wastewater treatment plant to recover waste heat from treated wastewater. The heat will be fed into the district heating network, where it will be sufficient...

Read more » Lue lisää »
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The benefits of using pushover analysis in earthquake engineering

Author Lauri Saarela
Posted on

In daily earthquake engineering, most earthquake analyses use linear or quasi-non-linear methods, where the non-linear behavior of structures is not taken into account explicitly during the analysis. The earthquake engineering field has long been in need of a performance-based analysis method that would also capture these non-linear effects i.e. inelasticity of structures.

Pushover analysis is a non-linear static method used in seismic assessment of buildings. It takes into account the non-linear behavior of structures and thus fills the void that usage of linear analysis types leaves. Even though pushover analysis has been around for a long time, it is still not very widely used in daily engineering. While linear analyses fail to meet the requirements regarding depiction of non-linear behavior of steel structures, pushover analysis is a valid tool for assessing the stiffness, strength and ductility/resiliency of a steel structure in the inelastic range. It also meets the simplicity requirements that are often present in daily engineering projects since the most accurate method, non-linear dynamic analysis, requires complicated data and is not simple enough to be used in daily engineering.

During an earthquake, a building oscillates back and forth, and certain structural elements are meant to absorb the oscillation energy. If the earthquake is strong enough, these structural elements may yield and buckle in the process of acting as fuses to absorb most of the shock, while leaving important load-carrying elements in the building intact. In non-linear dynamic analysis, the whole oscillation history of the structure is analyzed. Pushover analysis is a static method, which analyzes the single worst possible oscillation (target displacement) that the structure would have during the earthquake. Pushover analysis allows for a detailed estimation of which structural elements yield and buckle during the earthquake and how and when these plastic mechanisms develop. In other words, the capacity of the building can be determined.

The capacity of the building is depicted as follows: as the top-story displacement value is increased up to a certain value (target displacement), reaction forces at the base of the building (base shear) also increase. When a curve is plotted where the target displacement value is at the horizontal axis and the base shear force is at the vertical axis, a characteristic capacity curve, or a pushover curve, of the building is formed. An example of a pushover curve is shown in the figure below.


The design loads in elastic analyses that are derived from elastic earthquake spectrums, which are reduced to design spectrums using a so-called behavior factor. The behavior factor of a structure depicts the non-linear behavior, or over strength, that the structure possesses after the elastic capacity has been reached. These behavior factors are usually taken from codes and there is discussion in the literature, whether these factors are always correct. Pushover analysis allows for more realistic and structure-performance-dependent re-evaluation of the behavior factor as opposed to taking the behavior factor from a code just based on the structure type an incorporating it into an elastic analysis.


Pushover analysis is a very practical and reliable tool when applied correctly. It does not require complicated data. Combined with the N2-procedure in Eurocode 8, pushover analysis can be a valid tool for determining the target displacement, base shear loads, plastic mechanisms and capacity of a structure that is symmetric and low in elevation. It is especially useful in estimating which elements of a structure would fail under an earthquake loading and in determining how it affects the global stability of the structure.

The animation below shows a transient analysis on the left and a corresponding pushover analysis on the right. The animations have been synchronized so that as the highest value of oscillation occurs in the transient analysis, the pushover analysis animation is run to the same value following the same displacement pattern. The plastic mechanisms forming in the pushover analysis are similar to those in the transient analysis.

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Lauri Saarela

Konetekniikan DI. Olen toiminut Elomaticilla teknisenä laskijana vuodesta 2018. Työtehtäväni ovat vaihdelleet ydinvoimalaitoksen turvaluokiteltujen komponenttien seismisestä laskennasta elektroniikkalaitteiston eksplisiittiseen pudotussimulaatioon. Diplomityöni käsitteli pushover-analyysiä teräsrakenteiden seismisessä analysoinnissa. Harrastan mm. kamppailulajeja, kitaransoittoa, kalastusta ja frisbeegolfia.

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Latest post

20/09/2022

Vaasan Sähkö has commissioned Elomatic to design and project manage a future heat pump plant

Kirjoittanut By Elomatic Oy

Vaasan Sähkö will have a plant built at the Pått wastewater treatment plant to recover waste heat from treated wastewater. The heat will be fed into the district heating network, where it will be sufficient...

Read more » Lue lisää »
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