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Category: Handling

Hints, Tips & Tricks on cargo handling

MDI / PMDI / MMDI

MDI / PMDI / MMDI

Most owners / operators of chemical tankers that are able to carry such products will already have procedures in place for the handling of these chemicals. The most important item is to ensure that the tanks, lines and pumps are completely free of any moisture, purging with nitrogen to a dewpoint of -40C being the most common method of ensuring this requirement. However, there are cases where moisture has entered the tank, causing polymerisation with dried residues remaining on the…

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Molasses – Foaming

Molasses – Foaming

Normally, stored molasses seldom shows any unusual behaviour, however like all such extracts from plant-based production, it can deteriorate over time, and at elevated temperatures resulting in a loss of sugars. This results in fermentation, shown as a ‘gassing’ reaction, producing volumes of CO2 and Ethyl Alcohol. Mostly CO2. The ‘gassing’ reaction consists in small bubbles in the molasses which are retained in the bulk liquid for some time and which  manifests itself in frothing, and an increase in volume…

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Molasses

Molasses

Molasses is an easy product to carry and handle, however if problems occur the often create some spectacular results. The items below may then be of help. Enclosures Prior to loading Tanks should be free of traces of any previous cargo, odour free and dry. Open lines and valves check for water. Check and test heating coils and log test results. This is the only accurate means of calculating cargo quantity is by means of a Draft Survey, although the…

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Nitrogen or Air Blowing

Nitrogen or Air Blowing

The dangers of cargo tank overpressurisation by the introduction of nitrogen whilst undertaking the common practices of drying, purging or padding cargo tanks is well known and documented. What is less well addressed is the danger of tank overpressurisation when pigging or line blowing, especially when using air as a propellant. These dangers were first promulgated by IMO in ‘BLG 7/INF.7’ on 19 April 2002, in an ICS submission: ‘Chemical Tankers receiving nitrogen at high flow rates from shore’, where…

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Cargo Cooling

Cargo Cooling

We are all familiar with the IBC Code requirement 16.1.3: “Tanks carrying liquids at ambient temperatures shall be so loaded as to avoid the tank becoming liquid-full during the voyage, having due regard to the highest temperature which the cargo may reach.” However, there are many times when a chemical tanker has been diverted such that the vessel now finds the voyage route passes through temperatures at which the load calculation were not foreseen. The Panama Canal for example. Or,…

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Heating – Practices

Heating – Practices

Cargo Heating Practices This article, published by Standard Safety, in May 2016, gives some good all-round advice regarding heating of vegetable oils. Cargo Oil Heating Practices

Heating – Methods

Heating – Methods

Methods of Cargo Heating Thermal Oil Thermal Oil Heating Systems have been installed in a large number of chemical tankers during the last few years. Thermal oil fed directly to various types of coils is used in most of the chemical tankers built nowadays. To maximise heating efficiency both horizontal and vertical heating coils can be used in cargo heating. The pipe materials are stainless steel or carbon steel. Thermal oil may also be used in deck heating systems. A ‘food-grade’ oil can be…

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Blowing

Blowing

Line Blowing or Line Clearing is a procedure commonly conducted onboard most parcel and chemical tankers either with air or nitrogen supplied at a pressure around 7 bar. But is it an effective procedure? Is it a safe procedure? Nitrogen or Air? Effectivess Experiments in blowing of shore-pipelines show that many factors determine the effectiveness of such operations, but the line-diameter and line construction are by far the most limiting factors. The greater the line diameter, the greater the ‘stratification’…

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