Author: Greg Neneman, Valin Corporation
In order for the power plant to operate as efficiently as possible, proper filtration is a key part of the equation.
The benefits are obvious, but for some reason, filtering may sometimes not be a priority for plant operators and maintenance personnel, rather than what it really should be. In addition, the development of modern factories makes filtration more important because peak factories are used more frequently.
As more and more factories are equipped with equipment that generates electricity through solar energy during the day, they are now more dependent on peak power when the sun goes down. At these times when the solar energy is exhausted, the peak power plant will be activated to supplement the required energy.
The nature of spike plants used results in the need for proper filtration. If ignored, the consequences may be much more expensive. Although pinnacle power plants are designed to start relatively quickly, their operating costs are also higher. In addition, since many regions of the country rely on peak power generation during certain periods, maintaining the normal operation of peak power plants is absolutely the most important. Therefore, ensuring that the peak device fully filters ammonia is a top priority.
Any fuel-burning power plant in the country must comply with the guidelines set by the Environmental Protection Agency (EPA). One of EPA's main goals is to regulate air pollutants. In fact, the EPA has determined the maximum allowable level of NOx that can be released into the air. When factories burn coal, natural gas or solid waste, certain levels of nitrogen oxides are inevitably released.
Injecting ammonia water into the combustion zone of the furnace through fine nozzles can ultimately reduce the NOx level. Ammonia will produce a chemical reaction that produces extremely high temperatures.
However, this process is more complicated than most people realize. In order to start the process, ammonia must be sprayed directly into the flue gas, and it is expected that it must evaporate completely before reaching the catalyst. This is the key part related to this process, because if the ammonia droplet does not evaporate, it will inevitably be combined with the catalyst and therefore will not react with the gas. In fact, the only way to ensure that the ammonia droplets do evaporate is to keep them as small as possible through strategic filtration. In addition, whenever ammonia is used in industrial processes such as this, it must be 100% sure that there is no ammonia leak. This is strictly prohibited by the EPA.
Since the filtration of ammonia is very critical in this process, it is only natural that the process has a considerable number of nuances. Before selecting, sizing and installing a filter for this particular industrial process, several factors must be considered.
The first thing to consider is the size of the filter and the required micrometer or pore size. A filter with an inappropriate size can sometimes be as ineffective as there is no filter at all. In this case, how to determine the size of the filter? Three elements should be analyzed. The first is the distance from the bulk storage tank to the peak device. Second, the number of peakers in the facility will have an impact, and finally, it is necessary to understand the flow rate required by the ammonia system used in the peaker.
Once this information is collected, it will help guide the decision to use a sintered instrument filter or a pleated cartridge filter. The pleated cartridge filter is a simple process filter designed to filter contaminants that often appear in the process system. However, sintered meter filters are more used as a protection mechanism to capture abnormal particles. They all have their own advantages. For example, according to its intended design, a pleated cartridge filter will have a larger surface area than a sintered device filter. On the other hand, the sintered instrument filter has the advantages of small size and saving a lot of space.
In addition to the benefits, the needs of the process must also be considered. For example, if the process requires the use of a pleated cartridge filter, the material of the filter must be specified correctly. If the ammonia service requirement is 19% to 29%, a material must be used to meet this requirement.
When materials need to be designated for filters, it is important to fully understand the media designated for operation. The material must be able to withstand a period of time. If not, and the operator is not aware of the fault, the filter may not even exist. Of course, if the filter no longer exists in the process containing ammonia, it will have dire consequences. When discussing volatile substances such as ammonia, the problem of filter disintegration is more common. For this particular challenge, it is usually a wise decision to use a polypropylene, a material that retains well over time. The selected material needs to meet the corrosiveness of ammonia.
For such applications, wetted materials should also be considered. Again, in order to best explain the decomposition that may be caused by ammonia, it is important to choose materials that can withstand it. The ideal choice for wetted housing and gasket/sealing materials is usually 316 stainless steel and EPDM or Teflon packaging materials.
In addition to choosing the right filter and housing material for the filtration system that can handle the flow, there are also a lot of issues with ammonia cleanliness. In the power plant configuration in question, there is usually a large-capacity ammonia tank and other equipment according to the actual number of peak shaving devices on site. The cleanliness of the large amount of ammonia in the tank can put the well-known "curve ball" into the filtration process. Specifically, the inconsistent cleanliness of ammonia cannot be ignored. It is generally recommended to have multiple filtration stages in the process. A good suggestion is to place a shell with a mesh filter between the bulk delivery method and the ammonia storage tank to catch any large unforeseen obstacles. Due to the aggressive nature of ammonia, it is recommended that these filters be added to the regular PM plan.
In addition, it may be preferable to add filtration at the recirculation loop. Some processes use a standard filtration system at the specified micron level and another "pre-filtration" system downstream from the outlet side of the bulk tank. This additional filtration is usually specified as approximately one third of the original micron size. In addition, some factories use additional filtration stages at the smaller micron level. As we all know, this multi-stage filtration method is very effective.
Due to the nature of ammonia and its importance in the evolving power generation industry, proper filtration is essential. Failure to properly filter ammonia can lead to dangerous leaks and unexpected and costly plant shutdowns. In addition to understanding the size requirements, restrictions, and nature of the media, a multi-stage filtration process may be the best method.
About the author: Greg Neneman is the business development director of Valin Corporation, a leading technology solution provider in the technology, energy, life sciences, natural resources, and transportation industries. Valin uses automation, fluid management, precision measurement, process heating and filtration products to provide personalized order management, on-site support, comprehensive training and application expert engineering services.