Gas Detection in Waste Incineration Plants

At waste incineration plants, fuel derives from household waste, clinical waste, hazardous waste or biomass. Whilst these materials provide excellent sources of fuel, they emit dangerous gases which pose a threat to those working at the plant.

Gas detection equipment must be installed and used by personnel to adhere to health and safety regulations.

Waste to energy (WtE) is the process of producing energy from waste. Here, generated energy can be in form of electricity, heat or fuel or a combination. The method of incineration is considered one of the most effective and environmental friendly methods of waste management.

 

Waste Delivery Areas

The waste delivery areas otherwise known as the waste tip poses some of the biggest risks to workers and to the site itself. Refuse trucks dump the waste and it is stored until the grabber crane moves the waste into the furnace. Within this area, there are many different types of waste materials accumulating which poses several dangers. Not only does it smell bad, there’s a huge danger of the build-up of hazardous gases which are danger to workers but also increase the risk of damage to site.

Within the waste delivery and storage areas, fixed gas detectors are permanently installed to continuously monitor the risk of oxygen depletion, Carbon Monoxide (CO) and combustible gases.

 

Mitigate Fire Risk

In biomass sites, the storage area is used to store the wood pellets used to fuel the incinerator. Wood dust is one of the major causes of fires within the biomass industry. It is a problem where there are large quantities of material stored in a single silo or pile, and where material is damp.

The burning of an unconfined wood dust cloud has the potential to produce a flash fire. However, if the wood dust is contained within a full or partial enclosure, the pressure build-up can produce an explosion establishing the need for flame detection. Friction sparks can cause fires or explosions.

Breathe Safely

During the transport of powders and wood chip, fine particles become airbourne. Respirators are worn by workers to protect against inhaling dangerous substances such as dust or particulates, and gas and vapours, or any combination of these thus protecting the respiratory tract.

For short-term use, the AVIVA40 is suitable to protect against various airbourne hazards. For protection over the course of several hours, the Duraflow powered air respirator should be worn.

 

Process Monitoring

Maintenance workers, operations and any other workers within the plant should always wear a personal gas detector. Throughout the process, it's common for workers to be armed with personal gas monitors to protect against harmful gases such as CO2, Cl2, ClO2, HCl, NO2, O3, SO2 and SO3.

Portable gas monitors are the standard for confined space entry, allowing you to test an area prior to entry. These monitors are also worn on a person to continuously monitor, providing alarms and datalogging during operations.

Fixed gas detection is the best choice for achieving compliance providing around the clock monitoring. Gas sensors are installed in locations close to the source of potential leaks and areas where people are working such as CEM shelters to prevent possible asphyxiation.

 

NOx Abatement Storage Areas

NOx is considered a harmful greenhouse gas and substantial releases into the atmosphere are prohibited. A NOx abatement system is configured with a NOx reducing catalyst and an ammonia injection system. Ammonia is the catalyst that converts Nitrogen (NOx) into Nitrogen (N2) and water.

Ammonia is classified as an extremely hazardous substance and should be handled and used safely. The unloading stations, storage tanks, pumps, vaporisers and injection areas should all be monitored continuously. In the event of a leak, a fixed gas detection system is the most practical means of providing quick leak detection, alerting the plant to potential product loss and the possible dangers to personnel.

 

System Coolant

Hydrogen supply is stored at power plant premises as its absence can cause extensive damage to the machinery as a result of overheating. While Hydrogen is an effective cooling medium for the generators, it can also be hazardous. Being highly combustible, hydrogen leaks can be fatal as they can cause explosions and fires causing loss of life and destruction to plant and machineries. The cost associated with an unplanned shutdown can be costly for a power plant. Hydrogen molecules being light and small can leak from anywhere – between outages, the wear and tear on valves, seals and from storage areas.

Hydrogen gas safety is critical for power plant operators and hence proper practices must be followed for safe operation. Hydrogen gas detectors should be installed areas where hydrogen concentration could potentially reach explosive levels.

To reduce the risk of harm to workers and the plant, a fixed gas detection sensor is installed. With most industrial gas monitoring systems having 4-20mA, digital or relay outputs, they can be used to trigger existing plant such as extractor fans or turn off process supply lines, activate localised alarms to warn personnel of potential dangers before they happen.