Investigation on Pollution Control Device (PCD) In Foundry Industry to Reduce Environmental Chemicals

Right from the olden days, many products have been made according to foundry practices in order to generate prosperity in the societies in which they operate, while reaping these types of benets through the operation of foundries. It is alarming that the emissions released by foundries affect human health. Therefore, foundries installed Pollution Control devices (PCDs), in accordance with this development; researchers examined the effectiveness of these PCDs in controlling emissions from foundries in different parts of the world. The emission control obtained by installing these PCDs is explained in this article based on the data gathered from the survey. The result of the study indicated that the cartridge lter built into the induction furnace achieves the best eciency in controlling contamination from foundries. Interestingly, the operation of the cartridge lter has yet to be documented. Therefore, the construction, operation, the performance of the cartridge lter, and its eciency in achieving contamination control in foundries are described. The article ends by emphasizing the need to conduct surveys in foundries in which a cartridge lter is installed. The results of this study will provide useful information on the use of cartridge lters in induction furnaces to reduce foundry emissions. iron


Introduction
Most of the products in the world are made using foundry practices [1][2][3] . Foundry practices include melting metals, pouring these molten metals into molds, solidifying these molten metals in molds, removing solidi ed metals from molds, and cleaning these solidi ed metals 4 . These cleaned and solidi ed metals are called castings 5 . These practices are carried out in companies belonging to the foundry industry. The foundry industry provides products that are widely used in products such as pumps, automobiles, and compressors. Thus, the contribution of the foundry industry is vital and crucial to many economies 6 . However, emissions from the foundry industry cause pollution [7][8][9] . These emissions are mineral dust and organic carbon emitted during the melting, sand casting, and cleaning of castings 4,10−13 . With the growing concern about environmental issues, the pollution problems caused by the foundry industry must be seriously and urgently investigated (Collina et  Companies belonging to the foundry industry are more likely to come under public scrutiny, and therefore they are required to reduce emission levels by using pollution control Devices (PCDs). In this context, theorists and practitioners increasingly consider the need to install PCDs in the foundry industry (Mitchell, 2006;Rathi, 2003;Unnikrishnan and Hegde, 2007;Pham et al., 2019). In addition, European regulations have prompted the foundry industry to use PCDs [21][22][23] . Such regulations adopted in several countries have promoted the conduct of research in the foundry industry. The research described in this article was conducted against this background. The investigation reported in this article investigated pollution control using PCDs in iron foundries in the Tamilnadu State of India.
In Tamilnadu, a large number of companies produce products like wet grinders, pumps, and motors are largely manufactured. In order to cater to the needs of the iron castings used by these companies, the iron foundry industry has been existing as a major industry sector in Tamilnadu. An increasing number of iron foundry industries in Tamilnadu have improved the economy and quality of life of people. However, the pollutants emitted by these iron foundries affect the healthy living of people in Tamilnadu (Sosa et al., 2017;Li et al., 2018). Those pollutants are emitted due to poor production process, poor safety management, and low air pollution controlling practices employed while carrying out the foundry practices 25 . This has created a situation to install PCDs. As a result, some of the iron foundries situated in Tamilnadu have installed PCDs. This situation has revealed the need to study the impact of PCDs on controlling pollution in iron foundries located in the Tamilnadu State of India. In order to meet this research need, the study reported in this paper was carried out. Section 2 presents the details of the literature review conducted during the study reported here. Section 3, the history of carrying out pollution control in India, is narrated. In the same section, it is reported that no studies have been done on pollution control in iron foundries in the Tamilnadu state of India and describes attempts to gather relevant information from foundries in the Tamilnadu state. In section 4, the collected information is analyzed, and the same section describes the construction and operation of the cartridge lter and its ability to control contamination in foundries. In the last section, the article concludes with reference to the possibilities of continuing future research towards pollution control through the use of PCDs.
Pollution control in iron foundry: A review from literature arena Page 3/12 A literature search was conducted to nd research papers describing pollution control in iron foundries using PCDs. It was surprising that only eight papers reporting this type of research could be compiled from leading databases, namely Science Direct, Emerald Insight, and Springer. In total, these documents related to pollution control in iron foundries in three categories. Statistics from these articles reporting research in these three categories are presented in Fig. 1. As noted, two articles could each be grouped into categories 1 and 2. Four articles are grouped into category 3. These four articles have been reported by researchers who combine the topics covered in articles into categories 1 and 2.
The rst category examines the model and devices used to control pollution in iron foundries. In the second category, the application of PCDs in iron foundries in different parts of the world is evaluated. As noted above, the third category of articles addresses issues addressed in both the rst and second categories of articles. The information gathered from these three categories of articles is highlighted in the following subsections.

PCDs used in foundries
During the review of the literature reported here, two articles have identi ed that deal with devices used to control pollution in iron foundries. Information from these articles is highlighted here. Biswas et al., (2001)  Rabah, (1999) analyzed the pro tability of installing PCDs in iron foundries in Egypt. PCDs listed in this article include cyclone, cloth lters, electro lters, and wet scrubbers. This author presented data on total particulate matter emissions (in mg/nm 3 ) emitted from crucibles, short rotary, cupola, and electric induction furnaces from iron foundries in Egypt. After reviewing the economic considerations, this author concluded that wet scrubbing systems are the most suitable emission control equipment for iron foundry units in Egypt. Mukherjee, (2011) reported the scenario of foundries in the Howrah district of India. As Pal et al., (2008), this author also reported that SDC and TERI were encouraging foundries in India to use a DBC equipped with a venturi scrubber to control the pollution caused by dome operations. This author described the methodology of pollution control in foundries using three devices, namely the cyclone, the scrubber, and the fabric lter. Fatta et al. (2004) have investigated the emissions from foundries in Cyprus. These authors presented several guidelines for preventing pollution and emissions from smelters. An interesting suggestion is that the induction furnace is preferable to the cupola furnace to control contamination from iron foundries. These authors studied the use of wet scrubber and venturi scrubber to reduce foundry emissions. Lv et al., (2011) studied the release of PCDD / F from iron foundries in China. They said the anti-pollution devices used in Chinese foundries are the fabric lter, the cyclone, and the wet scrubber.
The literature review reported above indicates that signi cant efforts are being made to control exhaust fumes from iron foundries in various parts of the world. In carrying out these efforts, these foundries used devices.
From Table1, it is evident that different researchers are concentrating on the reduction of particulate matter. It is evident from various researcher nding from the year 2004 to 2020 that particulate matter concentration has reduced from 350 mg/Nm 3 to 38 mg/Nm 3 with different pollution control mechanisms such as Venturiscrubber, Cyclone, Wetscrubber, Wetcap collector, Dry cap collector as shown in the Table1. The current paper addresses the latest innovative technology of cartridge lters where the particulate emission is brought below 20 mg/Nm 3 . This nding will be a new milestone for the researchers and practitioners to select appropriate control devices, which will make the foundry industries to function hassle-free.  PCDS Employed and their impact in the iron foundries of Coimbatore: The study reported here was conducted in two phases. Initially, PCDs used in foundries in Tamilnadu were studied. To conduct this study, it was decided to select a sample foundry that would re ect the situation in Tamilnadu foundry units with regard to decontamination aspects. In order to choose the foundries in Tamilnadu to collect relevant data, it was necessary to identify the area that is severely polluted with ne particles less than 1µm [32][33][34]  After examining the above criteria, the two experts identi ed 24 iron foundries in Tamilnadu. The rst author preferred to add a foundry to this list even though it is not located in Tamilnadu. The reason this foundry has been included in the list is that it is a scienti cally managed foundry and features a relatively new PCD called a cartridge lter. This careful selection allowed us to collect relevant and authenticated data on the use of PCDs in these 25 iron foundries. These data represented approximately 1500 iron foundries in Tamilnadu. In this regard, a datasheet has been prepared to collect relevant data on the use of PCDs. By interviewing the managers of these iron foundries 4,9 , the data in this sheet is complete. In particular, the rejection rate, the GPS, and the pollutants before and after the implementation of the PCDs were entered into this sheet by questioning these o cials. These operators provided the data by referring to pollution data periodically submitted by external pollution control bodies such as the TSPCB.

Results And Discussion
Out of the 25 iron foundries, the PCDs installed in four foundries were not in good condition. For example, data was collected on PCDs that were effectively used in 21 iron foundries. These data are presented in Table 1. Even in these 21 iron foundries, some data could not be collected. For example, in Iron Foundry 4, the discharge rate prior to the installation of the wet plug manifold was not available. As this table shows, a dome is used in ten iron foundries. An induction furnace is used in the remaining 11 iron foundries. PCDs used in iron foundries equipped with cupola furnaces include cyclones, venturi wet scrubbers, energy-e cient scrubbers such as spray towers or wet cap and dry cap collectors 4,9 . The PCDs used in iron foundries built into an induction furnace are the wet scrubber; the venturi wet scrubber, the bag lter, and the cartridge lter. An interesting observation is that so far, no researcher has treated the cartridge lter as a PCD used in iron foundries. Cartridge lter not found. Referring to the data presented in Table 2, the impact of PCDs used in Tamilnadu iron smelters is described in the following subsections.

Impact of dry cap collector
As shown in Table 2, three of the 21 iron foundries surveyed installed a dry plug manifold. The dry cap collector is a kind of pollution control equipment mounted on the dome pole. A spark arrester is tted to the top of the dome. There is a cap with a de ector around the spark arrester. This assembly is called a dry plug collector. When dusty air enters the dry cap, particles settle at the bottom of the dry cap. Ba es are installed at the bottom of the dry cap. The ba es act as a barrier to prevent dusty air from escaping into the atmosphere. Clean air enters the atmosphere through the chimney. As shown in Table 1, a dry cap manifold equipped with a dome was found to reduce SPM from 1750 mg/nm 3 to 496 mg/nm 3 in foundry-3, 394 mg/nm 3 in foundry-7, and 366 mg/nm 3 in the smelter-9. In these three iron smelters, the particle concentration turned out to be higher than the speci cation of the CPCB, which is 150 mg/nm 3 4,9  Table 2, the wet cap manifold is installed in iron foundries 2, 4, 6, 8, and 10. The wet cap manifold is another type of contamination control equipment. The function of the wet hood collector is the same as that of the dry hood collector. The additional feature of the wet cap is that water is sprayed into the housing, which is mounted on top of the dome with a water bike line. The dusty air is cleaned at high speed by water, and the solid particles settle in the settling tank. The water is recycled using a pump. As shown in Table 1, in iron smelter 2, when the wet cap manifold is equipped with a dome, the SPM concentration is reduced from 2500 mg/nm 3 to 110 mg/nm 3 . In iron foundries 4, 6, and 10, no particulate matter concentration data were available before the installation of the wet plug manifold. The current concentration that occurred after the installation of the wet plug collector in iron smelters 4, 6, 8, and 10 was 110 mg/nm 3 , 102 mg/nm 3 , 95 mg/nm 3, and 105 mg/nm 3 , respectively. These values are within the emission limit of 150 mg/nm 3 4,9 Impact of Cyclone As shown in Table 2, the cyclone is installed in iron foundry 1. A cyclone is a device used to lter particles with a diameter ranging from 1 to 1000 micrometers from a gas or liquid stream. The centrifugal force throws solid particles against the outer wall of the cyclone. After their fall, they are collected and separated in the deposition chamber. Table 1 shows that when the cyclone was used in an iron foundry, the SPM concentration reduced from 300 mg/nm 3 to 67 mg/nm 3 . It was clear that the cyclone would be a suitable PCD to be installed in the dome to reduce contamination 4,9 Impact of wet scrubber As shown in Table 2, the wet scrubber is installed in iron foundries 13,14,15,16,17,18,19, and 20. The wet scrubber is a term used to describe a variety. Devices that use a liquid to remove pollutants. In a wet scrubber, the contaminated gas stream comes into contact with the washing liquid. The particles of the contaminated gas stream are collected by the liquid droplets. This phenomenon is achieved by dissolving or absorbing the particles in the liquid. Any droplets in the ue gases must then be separated from the clean exhaust stream using a device called a mist separator.
Most foundries have used wet scrubbers. The wet scrubber is very effective in removing both particulate matter and gases. During the study reported here, three iron foundries equipped with a Venturi wet scrubber and eight foundries equipped with a normal wet scrubber of different types (see Table 1) were followed. Interestingly, a remarkable reduction in particle emission concentrations was achieved in the Iron 17 smelter and the Iron 20 smelter. The SPM concentrations were found to be 52, 51, 50, 51, 55, 50 mg / nm3 in iron-13 smelter, iron-14 smelter, iron-15 smelter, iron-16 smelter, iron-18 smelter, and iron-19 smelter respectively. These values show that the reduced particle emission magnitude obtained after installation of the wet scrubber is only 50 mg/nm 3 4,9 Impact of Venturi wet scrubber As shown in Table 2, the wet venturi scrubber is installed in iron foundries 5, 11, and 12. A wet venturi scrubber is essentially a channel with a converging venturi-shaped groove followed by a diverging cross-section. They are leading a stream of contaminated gas from the dome. The liquid is usually introduced in the form of jets, which atomize rapidly to form many tiny droplets (Goncalves et al., 2004). The wash liquid is injected perpendicular to the incoming gas stream, breaking the liquid down into small droplets that are then used to collect particulate and gaseous pollutants. The energy required for diffusion is provided by a high-velocity gas stream. The quality of the liquid dispersion depends on the speed of the feed gas. A decrease in the gas velocity will result in a decrease in collection e ciency. A venturi wet scrubber has high separation e ciency for removing contaminants from the air. Table   1 shows that when the Venturi wet scrubber was installed in the dome, the resulting reduction in SPM concentration was 51 mg/Nm 3 in the iron foundry 5. When the venturi wet scrubber was installed in an induction furnace, the observed SPM concentrations were only 31 mg/nm 3 and 37 mg/nm 3 , respectively, in iron foundries 11 and 12. Therefore, the control of the contamination depends on the nature of the SPM expelled from the stack and the type of furnace being used 4,9 Impact of Cartridge lter As shown in Table 2, the cartridge lter is installed in foundry 21. It is pretty interesting to note that the use of the cartridge lter to control fouling from iron foundries has not yet been addressed by researchers. This is evidenced by the lack of papers stating that cartridge lters are installed in foundries. The cartridge lter equipped with an induction furnace in the iron foundry 21 reduced the concentration of SPM to less than 20 mg/nm 3 . This is the highest reduction in SPM concentration achieved as compared to that obtained by other PCDs discussed in the previous subsections (

Construction and Working Principle of Cartridge Filter
Information regarding the construction, operation, and performance of the cartridge lter is collected from Foundry 21. This information is presented in this section. The schematic arrangement in which three sets of cartridge lters are used to control fouling in a foundry is shown in Figure 2. The detailed view of the cartridge lter is shown in Figure 3. As illustrated, ue gases enter from induction furnaces into the gravity separator through the inlet channels. Gravity separators separate heavy particles from the vapours. These heavy particles pass through cartridge lter assemblies. In the cartridge lter assembly, heavy particles are screened with a at bag, and light particles of smaller sizes are released into the atmosphere. In this way pollution from combustion gases is reduced. Compared to other PCDs, the cartridge lter consumes less energy to control contamination from iron foundries. The construction of the cartridge lter assembly is so simple that it allows easy cleaning of the inner chamber and replacement of the at bag. When installed in an induction furnace, the wet scrubber is known to generate secondary pollution. On the other hand, there is no possibility for the cartridge lter to generate secondary pollution during use. During the study reported here, in the iron 21 smelters using a cartridge lter, the contamination level was found to be less than 20 mg/nm 3 . This pollution level is the standard set in European regulations. A minor drawback of using the cartridge lter is that it requires technically trained personnel to operate it. This minor inconvenience can be overcome by providing professional training to iron foundry operators to operate and maintain the cartridge lter.

Conclusion
Foundries have been manufacturing products necessary to improve the quality of human life since ancient times 4,9 . Many advances have been made over the years in foundry technologies and methods to produce high-quality and productive products. These developments have fueled the growth of foundries. Its growth has bene ted several companies around the world. Iron foundries, in particular, have played an important role in increasing the prosperity of various countries and regions. On the other hand, the development of iron smelters is being felt in different parts of the world as the ue gases emitted by smelters affect the environment, and therefore the healthy life of humans is affected. 37,38 . To compensate for this shortage, some PCDs are used in iron foundries. Some studies conducted by the research community in this direction have shown that the installation of PCDs and pollution prevention from smelters are in uenced and in uenced by local factors such as high costs, legal laws, lack of manpower, and skilled workforce. While research continues in this direction, it is surprising that the performance of Tamilnadu steel foundries from an environmental pollution point of view has not yet been reported in the literature. To ll this research gap, the research reported in this article was conducted.
After a literature review, relevant data were collected from foundries in the Tamilnadu State. The data collected indicates that the levels of contamination released by the induction furnace installed in foundries are lower than those in foundries that have installed domes. This derivation is con rmed by the guidelines of 30 . Another interesting observation is that a cartridge lter is used in only one foundry. The emission control level at this smelter was the highest compared to the installation of other PCDs. Details about the construction, operation, and performance of the cartridge lter are noticeably absent from the literature. That is why the details have been collected at the iron foundry in which the cartridge lter is equipped with an induction furnace. These details are presented in this article. A preliminary study showed that it is cheaper to install a cartridge lter than to install other PCDs in iron foundries. It is also striking that the maintenance of the cartridge lter in iron foundries is easier. The e ciency of the cartridge lter is so high that the SPM concentration released by it is lower than the standard value prescribed by European regulations. Amid all these advantages, the factors that can deter iron foundries from installing a cartridge lter need to be studied in more detail. At this point, this article concludes with an evaluation of the need to study iron foundries and examine the practice of using an induction furnace and a cartridge lter to reduce fouling and thereby the power generation capabilities of iron foundries. Schematic layout of Cartridge type lter assembly The detailed view of the cartridge lter