The materials handling sector is an important market for vendors of exhaust emission control technology, for two principle reasons: 1) machinery powered by internal combustion engines is frequently operated in confined spaces where the build up of toxic fumes can be dangerous 2) the products which are being handled are usually valuable and need to be protected from contamination or soiling. This is especially relevant where machinery is powered by diesel engines which emit black soot.

For further information on these problems and also on solutions available from Blackthorn, please see below:

In detail – toxic gases in confined spaces
The most notorious gas associated with confined spaces is carbon monoxide. This reacts with the victim′s red blood cells and reduces the amount of oxygen which can be carried around the body. At high concentrations, or after prolonged exposure at lower concentrations it can be fatal. However at an earlier stage of poisoning it can cause lethargy, lack of concentration and poor judgement. These are hardly the symptoms most employers would wish to find in an employee carrying out a potentially dangerous task such as driving a fork lift truck. Carbon monoxide is produced by both spark-ignition and compression-ignition engines, with spark-ignition engines being the higher producers. Another toxic exhaust emission worth noting here is the group known as aldehydes. These are irritants for the eyes, nose and throat. Again they are present in the exhaust gas of both spark-ignition and compression-ignition engines, but are especially severe with spark-ignition engines running on gaseous fuels. The problem is compounded if, as is often the case, the engines used are based on car engines first designed several decades ago, when far less was known about combustion chamber design than is now the case.

Solution – toxic gases in confined spaces
Catalytic converters can be fitted to both spark-ignition and compression-ignition engines. Their effectiveness against the most harmful toxic gases are as follows:

* Only applies to one of the following engines types:

1. Stoichiometric with closed-loop control
2. Lean burn
3. Rich burn with secondary air

For further details please click on the following links:

Catalytic converters – spark-ignition
Catalytic converters – compression-ignition

In detail – contamination by diesel particulates
Diesel particulate matter mostly comprises soot and liquid hydrocarbons. It possesses several characteristics which make it ideal for soiling and contaminating both products and buildings:

1. As it is black in colour it is highly visible
2. Individual particles can be very small and therefore may travel a long distance before settling
3. It is frequently oily and sticky
4. The particles often carry a static electric charge which helps them to adhere to surfaces

Please note – a single diesel fork lift truck with a 50kW engine can emit 50 grams of diesel particulate matter every hour

Solution – diesel particulate matter
Diesel particle filters can be fitted to forklift trucks, which are capable of reducing the mass of particulates emitted by about 99%.

Because of the low exhaust gas temperature of a typical diesel forklift truck, the exhaust heat alone is not sufficient to burn off the soot which is trapped in the filter. Therefore the standard practice is to make use of an external module containing an electric heating element and a fan which blows hot air through the dirty filter to burn off the soot. This process, known as ‘regeneration’, needs to be carried out after about 8 hours running, with the engine stopped. It typically takes about two hours to complete, and depending on the application the filter may either be left in situ or removed from the exhaust.

For further details of diesel particle filters systems available from Blackthorn, please click on the link below.

Diesel particle filters

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