Low-pressure pulse jet filters
These filters were, first of all, designed for the treatment of large flow rates amounting to app. 50,000 cbm per hour up to several millions of cbm per hour. The most characteristic feature of the low-pressure pulse jet technology is the low pressure of the blowing air vessel which is less than 1 bar whereas conventional systems are operated at 2 to 6 bar. For this reason, far less mechanical precautions need to be taken and the primary energy needed for the cleaning process is significantly less.
For cleaning the flue gas is routed to separate raw gas chambers via the raw gas duct and the raw gas butterfly valves. In order to prevent wearout and local deposits the flow is routed downwards into the hopper via deflectors with a preliminary removal of large particles taking place right there. The pre-cleaned gas, then, is brought to the filter bag from below and passes the filter media from outside to inside. During this stage the remaining impurities are removed. The supporting cages located inside the filter bags prevent collapsing of the bags during the filtration phase. The cleaned flue gas leaves the filter bags moving up into the clean gas chamber and is routed to downstream units via the clean gas header line.
Characteristic features of the Envirotherm-designed pulse jet baghouse filter which is basing upon LURGI technology are:
- High-volume dust loads in the raw gas.
- Low residual dust contents.
- High-intensity loads on filter surfaces can be handled.
- Long service lifetime of filter bags.
- Low loss of pressure.
- Low energy consumption.
- Quick change of filter bags without any interruption of operation allowed.
- Small number of diaphragm valves.
- Easy-to-maintain modular configuration.
Due to the above-mentioned features low-pressure pulse jet baghouse filters provide the following benefits:
- Low investment costs.
- High filtration efficiency (filtration efficiency levels of more than 99,99 % can be achieved).
- High equipment availability.
- Short delivery and assembly times.
- Low maintenance costs.
- Low operational costs.
Up to now, flue gas flows from various processes are subject to dedusting procedures by low-pressure pulse jet filters at a rate of more than 40,000,000 cbm of per hour.