Catalytic oxidation of methane : Modeling and simulations

©2020 VTT Technical Research Centre of Finlandfi=vertaisarvioimaton|en=nonPeerReviewed

Reduction of Particulate Matter Emissions in EU Inland Waterway Transport

In September 2014, the European Commission adopted a proposal on new requirements relating to emission limits and type-approval for non-road engines. The introduction of a new emission stage (Stage V) establishes extremely tight limits for particulate matter emissions for mobile non-road applications, including inland waterway vessels. These new emission limits will eventually require many ships to apply efficient exhaust gas after-treatment technology. The aim of this study was to find out which kinds of exhaust gas after-treatment solutions could fulfil these tightening particulate emission standards in EU inland navigation. A marine dual fuel engine was used as an example. The engine can be run both with gas and diesel fuel. The first part of the study consists of a literature review of various exhaust gas after-treatment technologies. This part serves as a general technology guide for particulate emission abatement from diesel engines. In the second part of the study, different supplier technologies and solutions were evaluated. The targets for particulate filtering system were defined and a specific inquiry was sent to potential suppliers. Based on the replies, passive diesel particulate filter systems with catalytic coating or/and an upstream diesel oxidation catalyst can be regarded as the primary choice for particulate emission control in inland navigation. This study was conducted as part of the EU Hercules-2 research and development programme, aimed at fostering environmentally sustainable and more efficient shipping.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

An evaluation of renewable fuels´ potential to reduce global and local emissions in non-road and heavy-duty on-road sectors

Achieving carbon neutrality in the European Union by 2050 requires deep reductions in greenhouse gas emissions in all forms of transport. Powertrain electrification and hybridisation are growing trends for light vehicles. Instead, electrification of maritime and heavy long-distance transport is far more difficult due to their massive energy needs. Battery technology is also problematic for mobile non-road machinery operating for long periods far from the charging infrastructure. However, fuel choices can significantly influence greenhouse gas emissions from internal combustion engines. Therefore, a transition to alternative fuels is one of the strategies under discussion. This study investigated the emission performance of two alternative fuels: biomethane and tall oil-based renewable diesel. In addition to greenhouse gas emissions, the harmful local emissions originating from fuel combustion were investigated. Biomethane was evaluated through a case study of a RoPax vessel operating in the Baltic Sea. In addition, real-driving emissions from a biomethane-powered city bus were measured. The study of renewable diesel´s emissions was carried out with engine experiments on an off-road diesel engine under laboratory conditions. Greenhouse gas emissions were calculated over the entire life cycle of the fuels. The results showed that using renewable fuels derived from sustainable biomass sources can reduce life-cycle greenhouse gas emissions by 65−90 % compared with fossil fuels. In addition, biomethane and renewable diesel can immediately improve local air quality by reducing local emissions. Burning liquefied biomethane reduced particulate matter by 80 % relative to marine diesel oil. Sulphur dioxide emissions were negligible and NOx emissions were low. Renewable diesel slightly reduced all regulated local gaseous emissions. The reduction in particulate number was more significant, at up to 26 % compared with conventional market diesel. Biomethane and renewable diesel proved to be effective ways to decarbonise transport in the short to medium term in hard-to-abate sectors with no immediate alternatives. The primary concern with biomethane and renewable diesel today is their limited availability. Guaranteed long-term policy is needed to scale up the supply of sustainably produced biofuels and accelerate the necessary investments.Hiilineutraaliuuden saavuttaminen EU:ssa vuoteen 2050 mennessä vaatii kasvihuonekaasujen merkittävää vähentämistä koko liikennesektorilta. Sähköistys ja hybridisaatio ovat kasvavia trendejä kevyissä ajoneuvoissa. Sen sijaan raskaan runkoliikenteen ja laivaliikenteen vaatimat suuret energiamäärät on vaikea korvata sähköllä. Liikkuvien työkoneiden kohdalla sähköistystä vaikeuttaa puuttuva latausinfrastruktuuri. Polttomoottoreiden kasvihuonekaasupäästöihin voidaan kuitenkin merkittävästi vaikuttaa polttoainevalinnoilla. Tämän vuoksi siirtyminen vaihtoehtoisiin polttoaineisiin on yksi keskustelun kohteena olevista strategioista. Tässä tutkimuksessa selvitettiin biometaanin ja mäntyöljypohjaisen uusiutuvan dieselpolttoaineen käytön vaikutuksia päästöihin. Kasvihuonekaasupäästöjen lisäksi selvitettiin polttoaineiden poltosta aiheutuvat haitalliset paikallispäästöt. Biometaania tutkittiin Itämerellä liikennöivään matkustaja-autolauttaan kohdistuvalla tapaustutkimuksella. Lisäksi tutkittiin biometaanikäyttöisen kaupunkibussin ajonaikaisia päästöjä todellisissa ajo-olosuhteissa. Uusiutuvalla dieselillä päästömittaukset tehtiin työkonedieselmoottorikokeilla laboratorio-olosuhteissa. Kasvihuonekaasupäästöt laskettiin polttoaineiden koko elinkaaren ajalta. Tulokset osoittivat, että kestävistä biomassalähteistä tuotettujen uusiutuvien polttoaineiden käyttö voi vähentää elinkaaren aikaisia kasvihuonekaasupäästöjä 65–90 % fossiilisiin polttoaineisiin verrattuna. Lisäksi biometaanilla ja uusiutuvalla dieselillä voidaan välittömästi parantaa paikallista ilmanlaatua, koska polton aikaiset paikallispäästöt vähenevät. Nesteytetty biometaani pienensi meriliikenteen hiukkaspäästöjä 80 % dieselöljykäyttöön verrattuna. Rikkidioksidipäästöt vähenivät 99 % dieselöljyyn verrattuna ja typen oksidit olivat alhaiset. Uusiutuvalla dieselillä kaikki säännellyt kaasumaiset paikallispäästöt olivat hieman pienempiä kuin dieselöljyllä. Uusiutuvalla dieselillä hiukkaslukumäärä laski jopa 26 % perinteiseen fossiiliseen dieseliin verrattuna. Biometaani ja uusiutuva diesel osoittautuivat tehokkaiksi keinoiksi vähentää liikenteen kasvihuonekaasupäästöjä lyhyellä ja keskipitkällä aikavälillä vaikeasti sähköistettävässä liikenteessä. Biometaanin ja uusiutuvan dieselin ensisijainen huolenaihe on niiden rajallinen saatavuus. Kestävästi tuotettujen polttoaineiden tarjonnan lisäämiseksi ja välttämättömien investointien nopeuttamiseksi tarvitaan päättäväistä pitkän aikavälin politiikkaa.fi=vertaisarvioitu|en=peerReviewed

Emission reduction by biogas use in short sea shipping

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Environmental and economic evaluation of fuel choices for short sea shipping

The shipping industry is looking for strategies to comply with increasingly stringent emission regulations. Fuel has a significant impact on emissions, so a switch to alternative fuels needs to be evaluated. This study investigated the emission performances of liquefied natural gas (LNG) and liquefied biogas (LBG) in shipping and compared them to conventional marine diesel oil (MDO) combined with selective catalytic reduction (SCR). For assessing the complete global warming potential of these fuels, the life-cycle approach was used. In addition, the study evaluated the local environmental impacts of combustion of these fuels, which is of particular importance for short sea shipping operations near coastal marine environment and residential areas. All three options examined are in compliance with the most stringent emission control area (ECA) regulations currently in force or entering into force from 2021. In terms of local environmental impacts, the two gaseous fuels had clear advantages over the MDO + SCR combination. However, the use of LNG as marine fuel achieved no significant CO2-equivalent reduction, thus making little progress towards the International Maritime Organization’s (IMO’s) visions of decarbonizing shipping. Major life cycle GHG emission benefits were identified by replacing fossil fuels with LBG. The most significant challenge facing LBG today is fuel availability in volumes needed for shipping. Without taxation or subsidies, LBG may also find it difficult to compete with the prices of fossil fuels.©2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license, http://creativecommons.org/licenses/by/4.0/.fi=vertaisarvioitu|en=peerReviewed

Biogas Utilization Opportunities in Ostrobothnia Region : findings from the project

This final report summarizes the key results of the "Biogas Utilization Opportunities in Ostrobothnia Region" project, which was conducted from March 2020 - September 2022 by the University of Vaasa. Reducing greenhouse gas emissions to the atmosphere, replacing fossil fuels with renewable fuels, and reducing waste play a key role in the EU's climate recycling targets. Biogas has a vital role to play in achieving these goals. However, the utilization of biogas in Finland is still limited, and it can be stated that the biogas market and the infrastructure enabling the market operation are still developing. The overall goal of this project was to build new knowledge and create favorable conditions for biogas business and biogas use to grow through techno-economic studies, measurements, and common operation models. Screening of real-driving emissions of a biogas-fueled city bus and the well-to-wheels analysis showed that up to 90 % greenhouse gas emission savings could be achieved by switching from liquid fossil fuel to biomethane. In addition to the biogas use as a traffic fuel, we investigated the possibilities of industrial operators and the local energy sector to switch to renewable biogas in their operations. To make biogas a realistic alternative for them and other potential new end-users – such as heavy transport and the maritime sector – the production and supply of liquefied biomethane, in particular, needs to be increased. Investments in local biogas liquefaction and a regional biogas pipeline could be the next major step in promoting biogas use in Ostrobothnia. The greenhouse industry could contribute with biomass waste material to biogas production. Biogas could in return also be employed in combined heat and power applications in greenhouse operations. Nonetheless, the greenhouse industry is already utilizing a lot of other bioenergy in heating. Carbon dioxide capture at biogas production plants is technically possible, and appears to be or become implemented at several sites in Europe. In the project, three biogas scenarios were created for Ostrobothnia, based on the findings from literature, interviews, and workshops as well as the project’s own calculations. The future direction of biogas solutions in Ostrobothnia is still unclear due to legislative issues, investment costs, and lack of knowledge. With sufficient support, the biogas sector can be expected to grow considerably.fi=vertaisarvioimaton|en=nonPeerReviewed

Real-Driving Emissions of an Aging Biogas-Fueled City Bus

Transition to low emission transportation and cleaner cities requires a broad introduction of low- and zero-carbon alternatives to conventional petrol- and diesel-powered vehicles. New-generation gas buses are a cost-effective way to reduce local air pollutants from urban transportation. Moreover, major greenhouse gas (GHG) savings may be achieved using biogas as the power source. The main objective of this research was to investigate CH4 and other gaseous emissions of a biogas-fueled urban bus equipped with a three-way catalyst (TWC) in real-world conditions. The study focused on emissions from a six-year-old gas-powered city bus, supplementing emission data from aging bus fleets. Impaired CH4 oxidation and NOx reduction were observed in the catalyst after its service life of 375,000 km–400,000 km. The main reason for low CH4 and NOx conversion over the TWC was concluded to be the partial deactivation of the catalyst. Another critical issue was the fluctuating air-to-fuel ratio. The results show that the efficiency of exhaust after-treatment systems should be closely monitored over time, as they are exposed to various aging processes under transient driving conditions, leading to increased real-world emissions. However, the well-to-wheels (WTW) analysis showed that an 80% GHG emission benefit could be achieved by switching from diesel to biomethane, giving a strong environmental argument for biogas use.© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

Different methods to improve the exhaust gas temperature in modern stage V 0ff-road diesel engine over transient emission cycles

This paper presents several methods to improve the exhaust gas temperature of a modern diesel engine. A high exhaust gas temperature is needed to improve the after-treatment system efficiency and particulate filter regeneration in low engine loads. This study is based on experimental measurements of two Stage 5 level off-road diesel engines. The effect of the different heating methods determined over steady state runs and emission and performance are presented with standard emission transient test procedure (NRTC). In the first step of the study, an intake air restriction and an exhaust gas restriction method are compared. The intake restriction produces better fuel economy over the measuring cycle. However, with the exhaust restriction, higher exhaust gas temperature can be achieved in low engine loads. In the second phase of study, the intake air restriction method was implemented in the research engine. In addition, active waste gate controlling, and injection retardation methods were taken in use for heating purposes. The engine performance was determined with normal calibration and with high exhaust temperature calibration. The differences to the exhaust temperature, engine performance and emission were presented in transient emission cycle NRTC.fi=vertaisarvioitu|en=peerReviewed

Selective Catalytic Reduction on Filter Performance Testing on Non-road Diesel Engine

High-efficiency lean-burn compression ignition engines are expected to continue to play an important role as a power source for non-road mobile machinery. The challenge for these engines is that they suffer both high levels of nitrogen oxide (NOx) and particulate matter (PM) emissions, and the simultaneous reduction of these particular emissions is difficult due to the trade-off relationship between NOx and PM. Consequently, achieving the most stringent emission limits requires efficient exhaust aftertreatment. Traditionally, NOx and PM have been controlled by separate aftertreatment devices. However, such sequential system configurations have several disadvantages, such as a large volume of the aftertreatment system. The compact design of a selective catalytic reduction (SCR)-coated diesel particulate filters (DPF), referred to as selective catalytic reduction on filter (FSCR), allows the reduction in aftertreatment system volume and mass. Another advantage is that the SCR can be placed closer to the engine to improve SCR temperature behavior. The major challenge of the FSCR technology is the interaction between the SCR and DPF functions. The present study examines the operation of a state-of-the-art combined particulate filter and SCR catalyst device as a part of an exhaust aftertreatment system on a high-speed non-road diesel engine. Unlike previous studies, the goal was a complete ammonia (NH3) slip-free operation. The main objective was to investigate how the SCR properties—NOx conversion and NH3 slip—change when the filter fills up with soot. In this context, tests with clean FSCR and with soot-loaded FSCR were conducted at varying urea dosing. The soot-loaded FSCR, compared with a clean one, showed a slightly (4-6%) lower NOx reduction and higher (1-4 ppm) NH3 slip under identical operating conditions. The results also indicated a decrease in NH3 storage capacity upon soot loading. Finally, a supplementary flow-through SCR catalyst was added downstream of the FSCR, and tests with FSCR only versus FSCR + SCR were performed. Adding the second SCR allowed for higher urea dosing without NH3 slip and, consequently, higher (+23%) NOx conversions.© 2021 The Authors. Published by SAE International. This Open Access article is published under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits distribution, and reproduction in any medium, provided that the original author(s) and the source are credited.fi=vertaisarvioitu|en=peerReviewed

Effects of Crude Tall Oil Based Renewable Diesel on the Performance and Emissions of a Non-Road Diesel Engine

Environmental concerns and government policies aiming to increase biofuel shares have led to the search for alternative fuels from a variety of renewable raw materials. The development of hydrotreated vegetable oil (HVO) type fuels has been strong in the Nordic countries, partly due to the early use of tall oil from the forest industry as feedstock. An innovative production process to convert crude tall oil (CTO) - a residue of pulp production - into high-quality renewable diesel fuel was developed by a Finnish forestry company UPM. Paraffinic, high cetane and low aromatic CTO renewable diesel allows efficient and clean combustion, resulting in reductions of local air pollution in addition to not releasing any new CO2 into the atmosphere during their combustion. This research investigated the influence of CTO renewable diesel on the performance and exhaust emissions of a non-road diesel engine. The examined fuels were neat CTO renewable diesel (BVN) and a blend of BVN and fossil diesel fuel oil (DFO) (50/50% v/v). Neat DFO served as the reference fuel. During a thorough test bench campaign, the engine was driven with the loads of the ISO 8178-4 C1 test cycle. The test engine had no exhaust after-treatment system, and no engine modifications or parameter optimizations were made during the tests. CTO renewable diesel proved to be beneficial in terms of CO, HC and particle number (PN) emissions. With neat BVN, a reduction of 9 % for CO, 10 % for HC, and 10% for PN compared with DFO were observed. The beneficial trends were most evident at low loads. Renewable fuel also slightly reduced brake specific NOx emissions. CTO renewable diesel proved to be a high-quality, sustainable alternative to fossil diesel and fully compatible with existing non-road diesel engines.©2021 SAE International.fi=vertaisarvioitu|en=peerReviewed