Use of Liquid Ring Vacuum Pump in Power Plant Industry
Liquid ring pumps are a revolutionary idea that changed the pumping and conveyance of liquids and gaseous products. Rather than relying on mechanical sealing between the vanes and the pump casing, a liquid ring is formed. The vanes attached to a rotating impeller, rotates the liquid to form an annular ring between the casing and vanes. This ring act as a sealant and the pump design allows the sacking of air bubbles on suction side and their removal on exhaust side.
Why choose liquid ring pump in power industry
The power industry such as geothermal, coal and nuclear plants operate using the Rankine cycle where heat is used to boil water to superheated steam which in turn rotates turbines at very high speed and torque. The turbine in turn rotates the generator providing electricity.
The need for liquid ring pumps in coal, nuclear and geothermal plants arise from two main activities. First there is need to remove gaseous films and exhaust gases from the steam and water entering the boiler. Secondly, there is need to remove gases from the condenser.
The liquid ring vacuum pump is reliable, durable, efficient and can used for heavy duty applications. The pump requires no seal between the rotating parts and this reduces wear and maintenance costs.Boiler feed water de-aeration system
The boiler in power generation is used to heat water to form steam. The feed water pumped to the boiler must be free of air to increase feed pump efficiency and eliminate difficulties of pumping water and air together. A liquid ring pump is fitted to remove the remaining steam and ensure that only liquid water goes to the feed pump.Use of liquid ring pump in condenser air extraction system
After steam expands in turbine, it loses it enthalpy, pressure and temperature. It therefore cools to form a mix of water and vapor. At the condenser, further cooling occurs. The pump is mounted at exhaust of the condenser. These pumps maintain a vacuum at the condenser side preventing turbine back pressure (condenser air hogging), remove any non condensable air and maintain a slight vacuum (holding). Single and double stage ring pump can be used depending on the plant size. Since the pump uses water, most water vapor will condense and non condensable air is eliminated.
The slight vacuum at condenser prevents pressure build up at the turbine exhaust ensuring that all steam is used to provide mechanical power to run the turbine and genset.Use of liquid ring pump in priming of condenser water box
The condenser accumulates air bubbles on top of cooling tubes and this reduces the heat exchanger efficiency, increase water pumping energy and creates air locks. Liquid ring pumps are the best to prime the system and eliminate air bubbles since they cannot be corroded.
Efficient flue gas extraction and desulphurization and filtration
Power plants utilizing fossil fuels, coal and waste biomass materials emit sulfur and other poisonous gases. Vacuum pumps are used to provide a vacuum filtering on flue gas desulphurization system before the gases are emitted through the stack. This process removes water vapor from gypsum and other ashes that can be recovered as dry materials.
This article has been posted by Ajit Joshi.