The latest CIMAC Guideline, developed by Working Group 17 “Gas Engines,” explores the influence of ammonia content in biogas on NOx and NH3 emissions in stationary gas engine .. more
The latest CIMAC Guideline, developed by Working Group 17 “Gas Engines,” explores the influence of ammonia content in biogas on NOx and NH3 emissions in stationary gas engine applications. Ammonia is commonly present in biogas, with concentrations reaching up to 2% by volume depending on the biomass source and gas cleaning quality.
During combustion, ammonia acts as a strong driver of NOx formation. Studies show that 60–100% of the ammonia in the fuel is converted into NOx, resulting in a measurable increase in exhaust emissions. If ammonia levels exceed manufacturer-specified limits, this can lead to non-compliance with emission regulations and reduced engine oil lifetime.
To ensure stable engine operation and environmental compliance, the guideline emphasizes the importance of maintaining ammonia concentrations below recommended thresholds—typically between 25 and 50 mg/Nm³ for fuels with a lower heating value of 10 kWh/Nm³. Effective gas cleaning and monitoring are essential to control these emissions.
This publication provides valuable insights for engine manufacturers, operators, and developers working with biogas-fueled systems. A follow-up paper will address NOx emissions in engines specifically designed for ammonia as a fuel.
CIMAC Working Group 17 now has released the “CIMAC Guideline Impact of Gas Quality on Gas Engine Performance”. It is an updated position paper on how gas engine performance is affected .. more
Digital Twins (DT) are virtual representations of physical assets, systems, or processes, created using real-world data to simulate, monitor, and analyze their counterparts. The Guideline examines .. more
With the publication of the first edition of ISO 6583:2024 - Methanol as a fuel for marine applications – General requirements and specifications, a number of questions will arise in the .. more
The document discusses the use of "conventional" and "unconventional" in regulatory frameworks, highlighting the lack of clear definitions in IMO documents and international standards. CIMAC .. more
The experts from #CIMAC Greenhouse Gas Strategy Group, Working Group 20 System Integration, Working Group 21 Propulsion, and the Maritime Battery Forum have consolidated their knowledge and .. more
In 2023, mainly during the period between March and July, an uncharacteristic number of operational engine issues were reported to have occurred after consumption of Very Low Sulphur Fuel Oils .. more
The safe handling of fuels on board ship requires four key component elements to align to ensure the fuel as delivered is safely and efficiently stored, cleaned, and conditioned prior to its .. more
This guideline is a revision of the CIMAC WG7 guideline No. 02:2016 [1] which was developed in order to provide information on how to apply the ISO 4259 approach to the interpretation of the .. more
Experience from the marine fuels market, since the introduction of the 0.50 % sulfur fuels, has shown that the blends making up the very low sulfur fuel oils have various sediment anomalies that .. more
One of the most readily available ways to decarbonise shipping is the use of biomass derived fuels. The current amount of available biofuel is not sufficient to reach the targets set. It is however .. more
In 2024, a new edition of ISO 8217 (edition seven) has been published. In the absence of an in-depth discussion of the various reports and associated background documentation that helped form the .. more
This publication is for guidance and gives an overview regarding Enabling the Implementation of a Ship-wide Data Ecosystem.
The publication and its contents have been provided for informational .. more
This guideline is about making new rules for stopping ships that use azimuthing thrusters. The current SOLAS rules don't consider modern ship designs with different types of propulsion systems and .. more
CIMAC WG 8 | Guideline: The causes of scuffing and actions to prevent scuffing in two-stroke engines
The latest publication from CIMAC WG8 ‘Lubrication' titled ‘CIMAC WG 8 | Guideline: The causes of scuffing and actions to prevent scuffing in two-stroke engines’ is now .. more
The latest publication from CIMAC WG7 ‘Fuels' titled ‘2022 Organic Chlorides, marine fuels incidents’ is now published and available for download.
In February and .. more
The latest white paper from CIMAC WG5 ‘Exhaust Emissions Control' titled ‘CCUS – Carbon Capture, Utilisation and Storage’ is now published and available .. more
The latest position paper from CIMAC WG15 ‘Control & Automation' titled ‘Cyber Security and Related Standards’ is now published and available for download.
This .. more
The latest Guideline from subgroup 'Monitoring Systems' of CIMAC WG20 'System Integration' titled ‘Monitoring Systems for Marine Hybrid Propulsion Systems’ is now published and .. more
The CIMAC Guideline ‘Hydrogen in Stationary 4-Stroke Gas Engines for Power Generation’ has been compiled by the CIMAC WG17 'Gas Engines' members and describes influence on gas .. more
A new position paper on future marine efuels now has been published by the CIMAC Greenhouse Gas Strategy Group. The intention of the paper is to indicate which eFuels are most relevant for future .. more
The CIMAC WG21 Guideline on the 'Hydraulics and Lubrication Rules of Steerable Thrusters' addresses a collection of questionable or unclear rules from classification societies, that are .. more
The CIMAC WG8 Guideline on the 'Lubrication of Reciprocating Gas Engines' brings together insights into and current practices for the lubrication of gas burning engines. Combustion processes in .. more
To achieve the needed greenhouse gas emission reductions in line with the IMO GHG Strategy and the Paris Agreement, the deployment of (net) zero carbon fuels is necessary – besides other .. more
With the Position Paper “Zero Carbon Energy Sources for Shipping”, the Greenhouse Gas (GHG) Strategy Group aims to communicate the need for zero carbon energy sources in shipping. To .. more
The guideline explains stability and compatibility of marine fuel oils in a practical way and provide advise on how to manage these fuel properties in the supply chain and onboard ships. Details on .. more
A number of shipping, refining, fuel supply and standards organisations have worked together to produce Joint Industry Guidance on the supply and use of 0.50% - sulphur marine fuel released on 20 .. more
In 2018, the industry experienced a series of marine fuel incidents impacting the operation of more than 100 vessels. The specialists of CIMAC WG7 Fuels have prepared a statement .. more
The guideline aims to understand the issue of cold corrosion which has been a regular occurrence with operators of large two-stroke marine engines due to engine operation at low loads. It .. more
The CIMAC Position Paper ‘Gas Engine Aftertreatement Systems’ has been compiled by the CIMAC WG17 'Gas Engines' members and provides an overview regarding the exhaust aftertreatment .. more
The CIMAC Working Group 7 Fuels has prepared and issued a guideline to provide answers to the questions that may arise with the publication of ISO 8217:2017, the latest specification of .. more
This guideline follows on from the CIMAC WG7 guideline No 09:2014 [1] which set out the differences between the ISO 4259 approach and that adopted under MARPOL Annex VI in respect of fuel .. more
The CIMAC Working Group 7 Fuels has prepared and issued a guideline on filtration of residual fuels. Traditionally, filters have been considered a safeguard for marine engines, however, a more .. more
This position paper describes how gas engines are influenced by the quality of the gaseous fuel provided. This topic is becoming increasingly important as highly fluctuating renewable energy .. more
New 0.10% sulphur (S) marine fuels recently introduced in the market offer an economically attractive alternative to conventional distillate fuels such as DMA. Before purchasing a new fuel product, .. more
With the introduction of MARPOL Annex VI, the sulphur content of a particular fuel oil is now often the primary factor in assessing whether or not that fuel oil is acceptable for intended use. .. more
The purpose of this paper is to consider the various types of fuel, and combinations of fuels, that may be used by marine vessels through to 2025, and then to discuss the potential impacts that .. more
Unburned Methane emissions from gas engines are of concern because of their contribution on global warming. Formaldehyde – a toxic interstage product of the Methane oxidation process – .. more
Over the last few years gas-fuelled engines have become more popular also in the marine industry both for on-board power generation and propulsion duties. Whereas the use of gas-fuelled marine .. more
Crankcase explosion is caused due to the overheating of one of the cylinders in the main machinery space. The consequences of the explosion is severe and it affects the working of other engines. .. more
In the current absence of an officially accepted specification for marine fuel containing more than 0.1% v/v biodiesel, this CIMAC publication provides background information and guidance to .. more
Discussions have started up at IMO about the need and potential for restricting black carbon (BC) emissions in the Arctic region caused by international shipping.
Especially regarding switch of .. more
This document has been prepared to advise the crew, users, vessel owners, charterers, crew, fuel and lubricant suppliers, equipment manufacturers, and classification societies about the fuel .. more
This document intends to collect information about the situations experienced where the Ignition and Combustion properties of the fuel are suspected of having influenced negatively on the .. more
On 10 October 2008, the IMO Marine Environment Protection Committee at its 58th session, by Resolution MEPC.177(58), has adopted amendments to the Technical Code on Control of Emission of Nitrogen .. more
Since many years discussions are ongoing between CIMAC WG2 and the IACS MP with regard to the use of Alu and/or Alu-alloys in engine rooms of category "A".
Today, mainly for 4-stroke medium and .. more
The presently available requirements with regard to the tightness of pipe connections for flammable, highly inflammable and potentially explosive media and fluids are clearly requesting tightness. .. more
This document provides the background information on black carbon emissions from large marine and stationary diesel engines. It discusses about the need and potential for restricting black carbon .. more
Recent emission regulations and the trend towards utilization of waste gases and renewable fuels have generated a rising interest in using gas engines in applications where Diesel/HFO engines were .. more
Current commercial residual fuel specifications cannot reliably predict the ignition and combustion characteristics of a fuel due to lack of a suitable test parameter. They cannot therefore protect .. more
This document briefly explains the importance of technique specific emission regulations. Some general features of the stationary engine plant are presented, such as:
engine types & fuel .. more
Ambient conditions depend on the geographical location and may vary with time of the year. The performance of an engine is influenced by the ambient conditions. The most important ambient .. more
LNG, liquefied natural gas, is natural gas cooled down to about –161 °C at atmospheric pressure and transported as a liquid. It is now rapidly becoming a widely used engine fuel in .. more
Control of Emissions of Air pollution from Locomotive Engines and Marine compression-ignition engines less then 30 litres per cylinder.
This publication discusses the following issues: .. more
Subject: Implementation of new or revised UR
Background
On the occasion of the last CIMAC WG2 meeting at Vaasa in April 2005 we ocassionally learned that some UR have been revised and .. more
Subject: Delivery of EIAPP Certificates
Background
Since that moment when the new IMO regulations regarding NOx came into force claims from engine builders increased. The engine builders .. more
Subject: Attendance at Type Approval Tests (TAT)
Background: Within the last years quite some experience was gained during Type Approval Tests. We have realized that Class surveyors well attended .. more
Use of low sulphur diesel fuels in coastal waters.
CARB / EPA propose that Ocean going ships must use only distillate fuels (diesel oil) with a low sulphur content and a low content of aromatic .. more