INTRODUCTION
Research rationale
Air pollution is a significant issue affecting urban, industrial, and handicraft villages in Vietnam, leading to adverse effects on human health, particularly respiratory diseases, as well as detrimental impacts on ecosystems and climate change, including the greenhouse effect, acid rain, and ozone depletion With the ongoing industrialization and urbanization, the sources of pollutants and the pressure on air quality continue to escalate, making environmental protection increasingly crucial.
The Thai Nguyen Steel Rolling Mill, a key investment for Thai Nguyen Joint Stock Company, was completed and became operational in 2005 as part of the company's production renovation and expansion phase Utilizing advanced technology from Italy's Danieli, the mill has a production capacity of 300,000 tons per year, boosting Thai Nguyen JSC's total output to 550,000 tons annually at the Can Thep Thai Nguyen Factory.
The Can Thep Thai Nguyen Factory, with its high production capacity, significantly contributes to environmental emissions, impacting ambient air quality Pollutants released during the production process stem from the combustion of fossil fuels, including coal and FO oil, resulting in harmful substances such as CO2, CO, SO2, NOx, and unburned organic matter like soot and dust These emissions pose serious risks to air quality and human health, particularly due to the presence of CO, CO2, SO2, NOx, and dust.
To effectively manage and reduce air pollution at the Can Thep Thai Nguyen Factory, it is essential to assess the current air quality situation This thesis, titled “Assessment of the Current Air Quality Situation in Can Thep Thai Nguyen Factory and Proposal for Mitigation Solutions,” aims to identify suitable solutions to address the air pollution problem.
Research’s objectives
- Assessing the air quality status of steel rolling factory of TISCO
- Propose measures of mitigate pollutants and poison gas treatment technology
1.2.2 Significance of study a Significance in studies and science researches
The implementation of this study enables students to engage with scientific research, enhancing their knowledge and bridging theory with practical application It equips them with essential skills in information collection, analysis, and processing, ultimately highlighting the significance of these competencies in their lives.
Air pollution is a critical global issue, especially in our country Effective management of factory air quality is essential to minimize emissions into the environment Regular monitoring of factory air significantly aids in environmental management and helps authorities detect any parameters that exceed permissible emission standards, allowing for timely and appropriate preventive measures.
Study assess air quality of factory exactly, is the base of the environmental protected evaluation of factory
Researching results is the basis for the selection of measures to reduce emissions of the factory, facilitate sustainable development.
Research questions and hypotheses
- What is an overview of Can Thep Thai Nguyen Factory?
- What is current situation of air of Can Thep Thai Nguyen Factory?
- What are possible management and technology solutions to reduce air pollution of the Can Thep Thai Nguyen Factory?
Limitations
Thesis was conducted during 3 months from March 2015 to July 2015
Thai Nguyen JSC operates 25 factories, making it challenging to conduct a comprehensive air quality survey across the entire organization Assessing air quality in a limited area may lead to inaccuracies, as pollution can stem from nearby factories, potentially skewing the results Consequently, the findings from this focused survey cannot be generalized to represent the overall air quality of the entire company.
Definitions
Air pollution refers to the release of harmful substances, including particulates and biological molecules, into the atmosphere, which can lead to serious health issues, environmental damage, and threats to food crops This pollution can originate from both human activities and natural sources.
Can Thep Thai Nguyen Factory: Start of construction on November 28, 2002, is a branch of Thai Nguyen Iron and Steel Joint Stock Corporation
8 Can Thep: means steel rolling
LIERATURE REVIEW
Theoretical base
There are many sources of air pollution It can be divided into natural sources and artificial sources
A volcano erupts, releasing hot lava and smoke that are rich in sulfides, methane, and other gases The ash and dust produced during the eruption can travel great distances due to the high altitudes at which they are expelled (Trieu, 2015).
+ Wildfires: The wildfire from natural processes occurs because of lightning, friction between dry vegetation such as bamboo, grass The fires often spread, emiss a lot of dust and gas (Trieu, 2015)
Dust storms are generated by powerful winds and storms, which erode desert soil and lift it into the air as dust Additionally, seawater evaporation, combined with sea wave foam, contributes to the dispersion of salt dust particles into the atmosphere (Trieu, 2015).
+ The process of decomposition, rotting carcasses, the chemical reaction between natural gas to form sulfide, nitrite, salts etc The type of dust, gases cause air pollutants (Trieu, 2015)
Artificial pollution sources are varied, but mainly due to industrial activities, burning fossil fuels and operation of vehicles Industrial pollution sources due to two production processes cause (Trieu, 2015)
Fuel combustion gases are released into the air through the kiln stack of the factory, contributing to pollution Additionally, evaporation, leakage, and losses on production lines and pipelines further exacerbate this issue The factory's ventilation system also plays a role, as it can either draw in or expel waste generated during production (Trieu, 2015).
The primary sources of air pollutants encompass various industries, including thermal power generation, building materials, chemicals and fertilizers, textiles and paper, metallurgy, food production, engineering enterprises, light manufacturing, and transportation, in addition to human activities (Trieu, 2015).
2.1.2 The harmful effects of air pollution a Emissions
- SOx: low concentrations of SO2 can cause smooth muscle spasms of the trachea, at higher levels will cause increased mucous secretion (Phuong, 2013)
Low concentrations of carbon monoxide (CO) can lead to symptoms such as headaches and dizziness At a concentration of 10 ppm, CO exposure increases the risk of heart disease, while levels reaching 250 ppm can be fatal Workers exposed to high CO environments often exhibit signs of pallor and emaciation.
Acute poisoning from nitrogen oxides (NOx) can lead to symptoms such as headaches and dyspepsia, while severe cases may result in blood changes, nervous system damage, and altered heart muscle function Prolonged exposure to nitrogen dioxide (NO2) can cause tracheal inflammation and mucosal irritation, with concentrations around 100 ppm posing a fatal risk.
Pneumoconiosis is a dust-related disease primarily affecting workers in industrial settings, where exposure to kiln gas, metal dust, and dirt is common Silicosis, a type of pneumoconiosis, is specifically caused by silica dust This condition can lead to serious complications, including tuberculosis and chronic lung failure Additionally, exposure to metal dust and dirt may result in mucosal edema and bronchial or tracheal ulceration (Phuong, 2013).
Thermal pollution significantly impacts the health of workers in high-temperature environments, such as steel rolling mills and kilns Exposure to elevated temperatures can lead to physiological changes, including excessive sweating and the loss of essential mineral salts (Phuong, 2013).
Pollutants that pose risks to human health also adversely affect animals, primarily through inhalation or indirectly by contaminating drinking water and vegetation These hazardous substances in the air can lead to significant harm to wildlife, emphasizing the interconnectedness of environmental health and animal welfare (Hoa, 2012).
Sulfur dioxide (SO2) concentrations of 3 ppm or higher in ambient air can negatively impact plant growth Elevated levels of SO2 can lead to the decline and death of trees, particularly deciduous species (Hoa, 2012).
- For the works and assets: factory's exhaust fumes contain dust and toxic gases as
Exposure to humidity can lead to the formation of corrosive acids like carbonic acid (H2CO3) from CO2, which can damage structural constructions and equipment, ultimately shortening their lifespan Additionally, noise and vibration can further contribute to the deterioration of these materials.
Noise and vibration are often directly effect on human auditory system, reduce hearing, cause headaches, reduce the efficiency of labor and workers' reflex If
12 regularly contacting with loud noise and vibration, workers may suffer deafness, or injury (Be, 2013)
The legal basis
- Environmental Protection Law of Vietnam No 55/2014 / QH13 dated 23/06/2014
- Circular No.28 / 2011 / TT-BTNMT 01/08/2011 of Ministry of Natural Resources and Environmental regulated technical processes of environmental monitoring ambient air and noise
- Circular No.21 / 2012 / TT-BTNMT dated 12/19/2012 Regulations on quality assurance and quality control in environmental monitoring
- Decision No 3733/2002 / BYT- Decision on promulgating 21 labor hygiene standard, 05 and 07 labor hygiene parameters
- Decision No 1931 / QD-BTNMT 11.12.2003 of the Ministry of Natural Resources and Environment of the decision approving the assessment report on environmental impact of Can Thep factory of 300,000 tons / year
- National technical regulations on environment
- QCVN 05:2013/BTNMT: National Technical Regulations on Ambient Air Quality
- QCVN 06:2009/BTNMT: National technical regulations on some toxic substances in the ambient environment
- QCVN 26:2010/BTNMT: National technical regulations on noise
- QCVN: 51:2013/BTNMT: National technical regulations on industrial emissions of steel production
An overview of the domestic and foreign research situation
2.3.1 Research situation over world a In general
According to new estimates from the World Health Organization (WHO), approximately 7 million people died in 2012 due to air pollution exposure, accounting for one in eight global deaths This figure more than doubles earlier estimates and establishes air pollution as the leading environmental health risk worldwide Addressing air pollution has the potential to save millions of lives.
London has emerged as the most polluted capital in Europe, experiencing up to 36 days of dangerously poor air quality since early 2014, exceeding the EU's permissible limit of 35 days per year This alarming air pollution contributes to approximately 4,300 deaths annually in the city, resulting in an economic loss of around £2 billion each year.
During winter, Ulan Bator, the capital of Mongolia, frequently experiences dense smoke that blankets the city, leading to limited visibility and frequent flight cancellations by airlines This persistent pollution not only makes breathing difficult for residents but also significantly impacts public health, contributing to rising mortality rates and an increase in respiratory diseases such as bronchitis, pneumonia, and lung cancer, according to Dr N Saijaa.
According to researchers from Berkeley Earth, a climate research organization in California, approximately 1.6 million people in China die annually due to health problems linked to the country's severely polluted air.
In the first quarter of 2015, a report indicated that fewer than 10 percent of 360 cities in China achieved national air quality standards, highlighting significant environmental challenges, particularly within the steel industry.
Steel plant operations are significantly impacted by air pollution, primarily due to the extensive use of coal, iron ore, limestone, dolomite, and sulfur This production process results in substantial emissions, including both stack and fugitive emissions, which release dust and gaseous pollutants such as sulfur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere.
A 2008 air quality monitoring study of the Integrated Steel Industry in Orissa, India, revealed significantly elevated levels of Suspended Particulate Matter (SPM) and Respirable Suspended Particulate Matter (RSPM) near the source, both in work and residential zones (p < 0.01) The highest recorded average SPM and RSPM values in the work zone were 4869 µg/m³ and 1420 µg/m³, while in the residential zone, they measured 294 µg/m³ and 198 µg/m³, respectively Notably, these values exceeded the National Air Quality Standards (NAAQS) (J Environ SciEng, 2011 Oct).
A study by M Tahir Chaudhary and Aysel T Atimtay on re-rolling steel mills in the Iskenderun Gulf Region of Southeast Turkey found that annual emissions of particulate matter (PM), sulfur dioxide (SO2), nitrogen oxides (NOX), and carbon monoxide (CO) totaled 19,951 tons, 40,833 tons, 10,764 tons, and 109,938 tons, respectively, along with 5,665 tons of other emissions The industrial sector accounted for over 95% of the total emissions of PM and SO2.
ISDEMIR, situated approximately 17 km north of Iskenderun city, boasts a production capacity of 2,200,000 tons per year, representing 37% of the total integrated iron and steel production capacity in the region The findings from the emission inventory indicate significant environmental impacts associated with this level of production.
The industrial sector is the predominant source of air pollution in the study area, accounting for a staggering 97% of total sulfur dioxide (SO2) emissions, 96% of particulate matter (PM) emissions, 73% of carbon monoxide (CO) emissions, and 68% of nitrogen oxides (NOX) emissions, as reported by M Tahir and Aysel in 2010.
Table 2 1- Pollution loads from the stacks of ISDEMIR
(Source: Management of air quality in iron-steel industry region in south-eastern turkey andemission inventory of several pollutants) 2.3.2 The research situation in Viet Nam
Vietnam has approximately 65 iron and steel production projects, each with a capacity of 100,000 tons per year or more Despite operating at less than 50% of their designed capacity, these steel factories consume nearly 3.5 billion kWh of electricity annually The steel industry accounts for about 6% of the total energy consumption in the industrial sector, largely due to outdated technology.
16 making a batch of steel is nearly twice the average number in the world in comparison (Cuong, 2015)
The production of 1 ton of steel generates significant environmental pollutants, including 0.5-1 tons of slag, 10,000m³ of emissions, and 100kg of dust The metallurgical industry contributes to a contaminated atmosphere, with nearly 60% of air quality affected The steel manufacturing process emits gaseous and solid waste, alongside noise pollution Notably, iron and steel production produces thousands of tons of dust annually, primarily composed of metal oxides such as FeO, MnO, Al2O3, SiO2, CaO, and MgO, along with various harmful exhaust gases.
CO, CO2, SO2, NO2 Arised dust containing oxides and other factors can affect human health directly as workers in factories (Cuong, 2015)
According to research by Prof Lam Minh Triet, PhD Nguyen Dinh Tuan (Environment and Natural Resources Institute, Ho Chi Minh National University):
Environmental quality monitoring at national stations indicates that the Hiep Phuoc power plant, located in the Hiep Phuoc industrial zone with a capacity of 675 MW, is a significant source of waste Each hour, this facility emits substantial quantities of air pollutants into the atmosphere, highlighting the environmental impact of industrial operations in the area.
In Ho Chi Minh City, emissions from steel plants, particularly from arc kilns, contribute significantly to air pollution, with an estimated output of 50,000 m³/h of exhaust gas The exhaust primarily consists of dust, with a pollution coefficient ranging from 20 to 30 kg per ton of product, and carbon monoxide (CO) with a coefficient of 7 to 10 kg per ton Consequently, the Southern Steel Company releases a substantial amount of pollutants into the environment each year.
- CO 994 - 1.420 ton/year Exhaust fumes from the craft metal foundries: exhaust fumes from this source contain pollutants such as SO2, CO, NO2, dust, cxhy (Triet and Tuan, 2010) :
Ba Ria-Vung Tau is home to five steel plants that generate approximately 650,000 tons of steel slag and 65,000 tons of dust annually, which contain impurities such as zinc, lead, and radioactive substances (Labour News, 2013).
According to environmental monitoring report in NhonTrach 5, NhonTrach district, Dong Nai Province:
METHODS
Methods of collecting secondary data
To collect and use documents relating to steel rolling factory of TISCO
Data on pollution management and air emission treatment in Vietnam and globally were gathered from various sources, including newspapers, seminars, journals, books, and online information.
To collect monitoring datas of the latest two years of the factory (2013, 2014) to ensure objectivity in the assessment of air quality of factory.
The actual survey methods
- Ambient air sampling by specialized equipment
- Measuring, sampling gas emissions sources by special machines
Table 3 1- Synthesis list of sampling and monitoring equipment
1 Equipment measuring of temperature, humidity, wind speed
2 Equipment of noise measuring with frequency analysis
3 Equipment of vibration Measuring America VI 100
4 Equipment of dust sampling America Staplex
5 Equipment for gas absorption Kimoto Japan Kimoto HS7
6 Equipment for gas absorption Apex America ZC 572-V
7 Equipment of measuring exhaust kiln stack Germany MSI 150 PRO 2-1
8 Portable generators Japan Kw SH 1900
9 Sample preservation cabinet YANMAR Japan CRB-1
Table 3 2- Synthesis of sampling location
Sampling symbols Monitoring location Coordinates
1 KK-3.06.1-1 In the steel rolling area 21 0 33’’N;
2 KK-3.O6.1-2 At the billet kiln 21 0 33’450’’N;
3 KK-3.06.1-3 At the finished product storage 21 0 33’455’N;
4 KK-3.06.1-4 In the factory’s office 21 0 33’450’’N;
5 KK-3.06.1-5 At the southern residential area; main port of TISCO company
6 KK-3.06.1-6 In the 17th household of residential area, Cam Gia Ward, Thai Nguyen City, far 200 meters from the plant to the northeast
7 KK-3.O6.1-7 In the residential area to the southwest, far 200m from factory
1 KTOK-3.06.1-1 At the Kiln Stack of factories 21 0 33’503’’N;
Characteristics of each sampling location
In the steel rolling sector, the production process can lead to thermal pollution, as the heat generated by technology, combined with solar radiation penetrating through walls or roofs, increases the internal temperature of the factory.
In the billet kiln, air movement is generated by the discharge of heat sources, while solar radiation heats the roofs, roads, and ground, resulting in temperature differences that further enhance air circulation.
At the finished product storage: The cargo loading-discharging and circulation of vehicles transporting materials and will cause noise pollution and arise dust
In the factory’s office: located near the workshop, with many passing vehicles, including vehicles of employees and containers containing finished product
The southern residential area, home to the main port of TISCO company, experiences the highest traffic density in the region Consequently, this area is significantly impacted by exhaust emissions, including dust and toxic gases, primarily generated by transportation activities at the port.
The 17th household in Cam Gia Ward, Thai Nguyen City, is situated 200 meters northeast from the plant, making it one of the two closest residential areas located at a safe distance in accordance with regulations and positioned at the end of the downwind.
In the residential area to the southwest: far 200m from factory: This is one of the two nearest residential area is located in a safe distance according to the provisions
The kiln stacks of factories release harmful emissions, including hazardous substances like ammonia (NH3), nitrogen oxides (NOx), sulfur dioxide (SO2), and significant dust The high temperatures within the kiln stacks contribute to the diffusion of these contaminants into the atmosphere.
The sampling process was equipped sufficiently with equipment, vehicles and manpower
During sampling, factory produced normally Weather: cloudy, no rain
Table 3 3- Sampling methods according to TCVN standard
Air quality - Weighing method for determination of dust content
Stationary source emissions Manual determination of mass concentration of particulate matter
Acoustics – Desription, measurement and assessment of environmental noise
Ambient air - Determination of the mass concentration of sulfur dioxide Tetrachloromercurate (TCM) pararosaniline method
Ambient air - Determination of mass concentration of nitrogen dioxide - Modified Griess-Saltzman method
Ambient air - Determination of the mass concentration of nitrogen oxides Photometric method using naphtyletylendiamin
Decision promulgate 21 occupational hygiene standards, 05 principles and 07 of occupational hygiene parameters
To ensure accurate sampling of ambient air, it is essential to collect samples at a height of 1.2 to 1.5 meters above the ground, which corresponds to the range of human breathing and minimizes the impact of surface dirt For gas emissions, samples should be measured and collected directly at the source All sampling, measuring, and analysis must adhere to ISO standards for reliability and consistency.
Aim Carry out measuring of temperature, odor, noise
- Using tongs to take the filter paper , then placed into the hopper
- Inserting the filterless into the sampling pump
- Giving an necessary amount for receivers
- Using tongs to take filter paper and put into storage box
- Recording volume, temperature, humidity, pressure
- Bring sterilized bottle and pumped to the place of sampling
- Using a pump to suck needed amount of air into the bottle
- add PdCl2 (or closed lid, immerse it in cold water during 30minutes, then add PdCl2)
- Using bottle to pour distilled water that brought to the place of sampling, pouring water into another bottle, then proceed adding PdCl2 as above
- Bring sterilized bottle and pumped to the place of sampling
- Sucking air into the bottle+20 ml Barit solution, then closed lid (immerse this bottle in cold water during 30 minutes the add Barit)
- Using bottle to pour distilled water in to another bottle +20ml of Barit solution as above
- Add to 2 serial absorber tube with 5ml absorbed solution in each tube
- Operating pump and get the necessary amount
- Close lid and record necessary data of volume, temperature, pressure
- Add to 2 serial absorber tube with 5ml absorbed solution in each tube
- Operating pump and get the necessary amount
- Close lid and record data of volume, temperature, pressure
- Add to 2 serial absorber tube with 5ml absorbed solution in each tube
- Operating pump and get the necessary amount
- Close lid and record data of volume, temperature, pressure
Practical methods
Sampling from the factory and analyzing samples in the laboratory is essential for processing data measured at the factory This ensures that the results are comparable to environmental regulations set by Vietnamese law.
Statistic and data processing methods
Arranging the collected results into statistical tables, charts, reasonable adjustment and included in the report, using Microsoft Word and 2 software Microsoft Excel for processing and plotting
RESULT
manufacturing technology process
Figure 4 1- Technology diagram (Source: Can Thep Thai Nguyen company) Notes to the technological scheme:
Billets, typically produced from large rolling mills or continuous casting machines, are made from low-carbon and low-alloy materials These billets come in cross sections of 150x150mm or 120x120mm and have lengths ranging from 6 to 12 meters They are sourced from TISCO or imported from international suppliers.
The billet admission process utilizes a 10-ton bridge crane to transfer billets via a roller conveyor into the kiln's inlet Once inside, the billets are organized by a roller system, which consists of nine rollers equipped with specialized water-cooling structures to maintain optimal conditions within the kiln.
In the kiln, billets are heated to temperatures between 1150°C and 1200°C before being pushed out by a hydraulic system This kiln has a capacity of 50 tons per hour and operates using heavy oil (FO), with a heat value of 9600 to 10000 Kcal/Kg and a fuel consumption of 270,000 Kcal per ton of product.
The billet is transported on a roller table system via pushing machine No 1 before reaching the cogging-down stand, which features an alternating arrangement of 6 stands—3 horizontal and 3 vertical—to prevent twisting during the rolling process After the initial rough rolling, the heads of the billets are trimmed using a crankshaft cutting machine, followed by refined rolling through a system that includes 4 refined and 4 intermediate rolling stands Finally, the billets are cut at both ends by cutter No 2 and processed through Block-10 stands, resulting in the creation of final products tailored to specific types.
After passing through the final rolling stand, steel undergoes heat treatment with water to enhance its surface properties, mechanical strength, and weldability It is then transported via pipe systems to the cold floor system, where it is moved using a catenary system and roller table to a cold cutter, cutting the steel to a commercial length of 11.7 meters Finally, the steel is taken to the packing area for balancing, labeling, and warehousing.
After passing through the final stand of the QTR equipment, coil steel is processed by pushing machine No 4 on the looping mill, then transferred to a cooling floor This process culminates in the collection of steel rolls in the designated pit.
28 moved to presses roll machine, then was closed, tied on weighing systems, loaded into warehousing.
Air environment status in Thai Nguyen Can Thep factory
4.2.1 The air parameters need to be analyzed
Ambient air quality is assessed through various parameters, including total dust, sulfur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), noise levels, humidity, temperature, and wind speed Measurements were taken along the axis through the center of the plant, specifically at the kiln stack, extending downwind in multiple directions.
Gas emission source includes parameters: total dust, SO2, NOx, CO, NO2, CO2, O2
Table 4 1- Sources of emissions from the plant's activities
Source Unit Emissio ns volumes
The production stages of rolling steel contribute significantly to air pollution, primarily through emissions from the billet kiln and steelmaking processes The burning of fuel in boiler kilns, along with emissions generated by machinery, equipment, and transport vehicles, further exacerbates the issue However, quantifying these emissions in cubic meters per year remains a challenge.
Dust Arising primarily from the manufacturing process and handling
Mental dust Metal dust arising from bleaching stages, polishing rusty metal surfaces and during rolling process
Noise Arising mainly from the operation of machinery and equipment, process of bringing materials , and shipping products
Noise and vibration pollution from kilns, dust filtration systems, and water supply equipment in Can Thep, Thai Nguyen, which produces 300,000 tons per year, directly affects workers' health and well-being.
The noise from the activities of the kiln, the machinery, equipment, transport vehicles dBA
Sampling result in Kiln stack are
Temperature at kiln: = 245 0 C Environmental temperature: = 25,3 0 C
Table 4 2- Sampling result in the steel rolling area
Gas: SO 2 Gas: NO 2 Gas: NH 3 Gas: CO
(ml) 10 ml 10 ml 10 ml 1,0 ml
Table 4 3- Sampling result at the billet kiln
Gas: SO2 Gas: NO2 Gas: NH3 Gas: CO TSP PM 10 Metal
(ml) 10 ml 10 ml 10 ml 1,0 ml
Table 4 4- Sampling result at the finished product storage
SO 2 Gas: NO 2 Gas: NH 3 Gas: CO TSP PM 10 Metal
(ml) 10 ml 10 ml 10 ml 1,0 ml
Table 4 5- Sampling result in the factory’s office
SO 2 Gas: NO 2 Gas: NH 3 Gas: CO
(ml) 10 ml 10 ml 10 ml 1,0 ml
Table 4 6- Sampling result at the southern residential area; main port of TISCO company
SO2 Gas: NO 2 Gas: NH 3 Gas: CO TSP PM 10 Metal
(ml) 10 ml 10 ml 10 ml 1,0 ml
Table 4 7- Sampling result in the 17th household of residential area, Cam Gia Ward, Thai Nguyen City, far 200 meters from the plant to the northeast
SO 2 Gas: NO 2 Gas: NH 3 Gas: CO
(ml) 10 ml 10 ml 10 ml 1,0 ml
Table 4 8- Sampling result in the residential area to the southwest, far 200m from
SO 2 Gas: NO 2 Gas: NH 3 Gas: CO
(ml) 10 ml 10 ml 10 ml 1,0 ml
4.2.3 Results of measurement and sample analysis: (surveyed from March 27 to April 5, 2015)
Table 4 9- Result of measuring and analyzing dust, noise in the manufacturing area in 2015
Recent measurements of gas analysis and dust levels in the production area of the plant indicate that all analyzed indicators are within permissible limits as per decision 3733/2002 / BYT Additionally, noise levels in the region ranged from 63.1 to 83.7 dBA, remaining within the acceptable threshold established by the same regulation.
Table 4 10- Result of measuring and analyzing dust, noise in the outside of manufacturing area in 2015
Comment: The measured results, analyzing the gas in locations surrounding the production area showed entire analyzed indicators are within permissible limits when
34 compared to standard QCVN 05: 2013 / BTNMT, QCVN 06: 2009 / BTNMT AND
All ambient environmental monitoring being impacted are not contaminated with noise, dust and toxic substances such as SO2, NO2
Table 4 11- Result of measuring and analyzing kiln stack emission in 2015
Comment: Analytical measurement results in kiln stack emissions of kilns showed entire analytical indicators are within permissible limits with standard QCVN 51: 2013
4.2.4 Comparing survey results for 3 consecutive years 2013, 2014 and 2015
Table 4 12(a) - Comparison of air quality in factory area between 3 years 2013,
Pollutants content Noise (dBA) Total TSP (mg/m 3 ) NH 3 (mg/m 3 )
(Source: Thai Nguyen center of Monitoring and Environmental Technology)
Over the past three years, noise levels have been on the rise; however, all indicators remain below the permitted limit of 85 decibels In manufacturing areas, total Total Suspended Particles (TSP) in 2015 were higher than in the previous two years Conversely, outside the manufacturing zone, TSP levels at the main port of TISCO Company reached 0.52 mg/m³, while in the residential area of the 17th household to the northeast, TSP levels decreased fourfold Additionally, the concentrations of TSP and ammonia (NH3) have shown an upward trend over this period.
Table 4 13(b) - Comparison of air quality in factory area between 3 years 2013,
NO 2 (mg/m 3 ) SO 2 (mg/m 3 ) CO (mg/m 3 )
(Source: Thai Nguyen center of Monitoring and Environmental Technology)
Comment: apart from kiln stack, the measuring result in other areas obtained relugulation The toxic concentrations as NOx, SO2, CO are not significant
2013 nam 2014 nam 2015 nam 2013 nam 2014 nam 2015 nam 2013 nam 2014 nam 2015 nam 2013 nam 2014 nam 2015 nam 2013 nam 2014 nam 2015
TSP NH3 NOx SO2 CO mg/m 3
Figure 4.2 Figure 4 2- Chart of substances concentration changing in kiln stack exhaust emissions during 3 years
The kiln stack exhibits a significantly lower dust emission level of 41.3 mg/m3; however, the concentrations of NO2, SO2, and CO are several times higher While these emissions remain within permitted limits, certain indicators have shown an upward trend from 2013 to 2015, although SO2 emissions have decreased notably during this period.
Figure 4 3- Chart of noise level in manufacturing area during 3 years
Steel Rolling area billet klin area Finished product storage
Figure 4 4- Chart of noise level in outside manufacturing area during 3 years
Commenting and evaluation on the status of air sources in Can Thep Thai
Monitoring results from the factory reveal variations in air quality across different locations, both inside and outside the production area Gas analysis and dust measurements indicate that all analyzed indicators remain within permissible limits as per decision 3733/2002/BYT Additionally, noise levels in the region ranged from 63.1 to 83.7 dBA, also adhering to the thresholds established by decision 3733/2002/BYT.
The analysis of gas measurements from locations surrounding the production area indicates that all evaluated indicators fall within the permissible limits set by the standards QCVN 05: 2013 / BTNMT, QCVN 06: 2009 / BTNMT, and QCVN 26.
Factory's office Main port area
2010 / BTNMT.All ambient environmental monitoring being impacted are not contaminated with noise, dust and toxic substances such as SO 2 , NO 2 …
Analytical measurement results in kiln stack emissions of kilns showed entire analytical indicators are within permissible limits with standard QCVN 51: 2013 / BTNMT
Noise levels in the manufacturing area, particularly in the rolling and billet kiln zones and finished product storage areas, exceed 80 dBA, significantly higher than the surrounding area's noise levels of over 60 dBA Additionally, total suspended particulate (TSP) dust concentrations in the production area consistently exceed 0.1, while the surrounding areas register less than 0.1, except near the factory's main gate, where high traffic results in dust levels of 0.52 Furthermore, while the kiln stack emits gas with a lower dust content of 41.3 mg/m³, it presents significantly elevated levels of NOx, SO2, and CO compared to both the production and surrounding areas.
Between 2013 and 2015, certain indicators, while remaining within permitted limits, exhibited an upward trend, particularly in areas such as the rolling area, storage area, main port, and southwest residential zone, with notable increases observed in kiln stack noise levels.
Concentration of NO x increases from 141 to 160 mg/m 3
Concentration of dust increases sharply from 19,7 to 41,3 mg/m 3
Concentration of NH3 increases sharply from 119 to 160 mg/m 3
Research of measures for air pollution mitigation in Can Thep Thai Nguyen Factory
4.4.1 Technology and measures of exhaust gases treatment is being applied by factory
The factory prioritizes the implementation of source mitigation measures, ensuring that vehicles, machinery, and equipment are regularly maintained for optimal performance This proactive approach effectively limits noise, vibration, and emissions Additionally, routine checks are conducted to monitor wear and ensure that lubricants are replaced periodically for machines.
Workers are provided with essential workwear, including hats, gloves, and protective clothing, to ensure their safety Factories pay special attention to employees in high-noise departments by implementing alternative work arrangements, organizing reasonable schedules, and dividing work into three shifts to promote a healthier work environment.
30 minute for break Time off is calculated in the working time
Periodic health checks are holded annually 1time / year Workers in dangerous places will be overhauled 2 times / year to detect early illness due to noise
Trees were planted in the factory and on transport routes to reduce noise, dust and emissions
Water was sprayed regularly to reduce dust in the area surrounding the factory Using heat exchanger make use of heat into the kiln (drying FO oil from 80-
To mitigate the impact from transportation vehicles to the lowest level, the factory has applied the following measures:
+ Before contracting delivery, vehicles as well as vehicle owners have to ensure the technical conditions and other requirements for transport on the road
+ Cars are maintained regularly in accordance with regulations, ensure proper tonnage and strictly abide the regulations on vehicles circulating
+ Regulation speed for the vehicles circulating in the factory area
Air pollution primarily originates from factory emissions, particularly exhaust fumes from kiln stacks Key pollutants include temperature variations, sulfur dioxide (SO2), and nitrogen oxides (NOx) The flue gas treatment technology utilized by factories is illustrated in the diagrams below.
Figure 4 5- Diagram of exhaust fumes treatment technology
(Source: Can Thep Thai Nguyen Factory) Notes to the diagrams of exhaust fumes treatment technology:
During operating, the temperature of smoke in kiln is very high from 1100 -
1150 0 C In order to take this heat back, the indirect heat exchanger will be used Hot gases from the kiln (1) enters the heat exchanger system (2), clean air from outside is
Air is drawn through the heat exchanger tube, where it is heated before being supplied to the kiln by a fan The exhaust gases exiting the heat exchanger reach temperatures between 300-4000 °C During this heat transfer process, dust precipitation occurs as the flue gas, having been cooled, allows suspended dust particles to settle onto the heat transfer surface due to gravity.
This device imported with steel rolling mill line of DANIELI - ITALIA Therefore it gets high level of synchronized Dust removal efficiency reaches 95% in this device
4.4.2.1 Overview of treatment NOx, NH3, dust a, For toxic gases
Adsorption is a process that involves the dissociation of gases due to the affinity of specific solids for certain gases, particularly in exhaust gas mixtures During this process, exhaust gas molecules adhere to the surfaces of solid materials, which are referred to as adsorbents The gases that are captured in this manner are known as the absorbed substances.
There are two types of adsorption: physical adsorption and chemical adsorption:
- Physical adsorption: is a multi molecular adsorption (multiple layers adsorption), binding force is an attractive force between molecules (Vander force - Waals) not forming surface compounds
- Chemical adsorption: the single molecule adsorption (a layer adsorption), binding force is chemical force that create the surface compound
- Adsorbent materials: the porous material with large internal surface, is formed by synthetic or nature
- Adsorption materials must meet the following requirements: Adsorption capacity is high, effected scope is broad, having the necessary mechanical strength, ability to revert easily, cheap price
Adsorbent: conventionally are substances such as activated carbon, silica gel, activated alumina, zeolite …
- Activated carbon: characterized by hydrophobic properties, so it is widely used to treat various forms of moisture Basic drawback of activated carbon is inferior mechanical strength and flammable
- Silicagel: the amorphous silica hydrated (SiO2 nH2O), silica is fireproof, low regenerated temperature (110-2000 C) and sufficient mechanical strength However, it is destroyed by the humidity drops
Activated alumina (Al2O3.nH2O, where 0 < n < 6) is produced by heating various aluminum hydroxides This durable material is effective in moisture-sensitive environments and is utilized for reclaiming polarized organic compounds and facilitating air drying processes.
Zeolites are microporous aluminosilicate minerals characterized by their high sorption capacity and the presence of alkali metal oxides and earth alkaline elements Their general chemical formula is Me2/nO.Al2O3.SiO2.7H2O, where Me represents alkali metal cations and n denotes their valence.
44 steam Maintaining highly active at relatively high temperatures (150 - 250 ° C) is the outstanding advantage of zeolite
Activated carbon effectively adsorbs nitrogen oxides (NOx); however, when in contact with these gases, coal poses a risk of fire and explosion Moreover, coal's low mechanical strength can lead to its degradation, resulting in the conversion of NOx into nitric oxide (NO).
Despite their mechanical strength and non-flammability, the absorption capacity of Nox and silica gel is lower than that of activated carbon However, their recovery process can convert NOx into NO, similar to the functionality of activated carbon.
Both adsorption NOx efficiency and mechanical strength of Activated alumina is low
Absorption is a process that involves the interaction between exhaust emissions and solid materials, leading to the dissolution of gases in a liquid or the transformation of these gases into less harmful substances This method relies on the contact between air and a solid sorbent, resulting in a two-phase system that depends on the interactions between the absorber and the substances present in the gas phase.
Absorption method is divided into two types: physical absorption and chemical absorption:
- Absorb physics based on the solubility of the gas phase constituents in the liquid phase
- Absorb Chemical: absorber involved chemical reaction with absorption solvent
- To absorb nitrogen oxides people use water, alkaline solution, acids and oxidizers
Depending on the exposed area between the flue gases and liquids, duration of exposure, environmental concentration and reaction rates between the absorber and emissions b, For dust
Based on the concentration of dust, chemical properties, physical properties, demand for air circulation and filter dust away from the air is divided into 3 levels:
- Cleaning: only retain dust particles of size> 100 mm (preliminary filter)
- Intermediate cleaning: not only big particles but also small particles are retained Dust concentration after filtering is about 30 - 50 mg / m3
- Refined cleaning: can filter dust particles smaller than 10 mm with high performance Dust concentration after filtering is only 1-3 mg / m3
Measures to limit and handle pollution from noise and vibration:
Pollution being caused by noise and vibration in the steel mill with capacity 300.000 ton/year will impact on workers directly Some measures limiting the noise pollution will be implemented:
- To minimize noise at source and allocate anti-noise devices such as earplugs for employees working in the noise departments
- To isolate reasonably sources of noise into private locations
- The great shocking machine was concerned to deal during laying the foundation
The production chain primarily generates noise and vibration from machine actuators; however, the high-quality equipment imported from DANIELI - ITALIA operates with minimal noise and vibration.
- To install silencers system in some locations that wind blowing out
- Planting trees around the factory to create noise separators
Measures of reducing thermal pollution and against heats:
The workshops were strategically designed to maximize the benefits of natural ventilation, featuring windows and skylights that enhance airflow throughout the factory With impressive heights of approximately 14 to 16 meters, the workshops promote effective ventilation Insulated roofs and walls further contribute to energy efficiency, while ventilators and coolers ensure a comfortable working environment for employees Additionally, the surrounding areas are spacious, facilitating effective heat dispersion.
Measures to prevent environmental incidents:
Factory fires can pose significant environmental risks, often caused by fuel oil, flame welding, and cutting processes To mitigate these hazards, strict explosion prevention regulations are essential.
Machinery and equipment working at high temperatures and high pressures have clear origin and strict implementation of periodic inspection regime
Factory has sufficient earthling system for the equipment, machinery, buildings as well as the firefighting equipment, water system
Measures of sanitary - occupational safety:
To comply thoroughly the provisions of labor safety for employees, organize training annually for employers and periodic 2 times/year for workers
To inspect and surveillance periodically the health of workers and staffs, timely detect occupational diseases
To organize annual work environment inspection for the direct producing areas to ensure the working environment of the employees are the best
Raising the environmental consciousness of workers through media programs billboards, posters
- To build regulations on environmental protection in the factory as follows:
- Regulations on the functions and responsibilities of each office and workshop in industrial hygiene- safety and environmental protection
- Regulation on the powers of managers in the implementation of their duties
- Regulation of reward for the collective and individual having initiatives in the reducing pollution for factory
- Regulations dealing with the collective and individual acts of irresponsibility in occupational safety - explosion prevention - environmental protection
The factory is being implemented environmental management system ISO
14000 by Thai Nguyen Steel Joint Stock Company:
- To strengthen education on safety, industrial hygiene, environmental protection
- To inspect and supervise regularly the implementation of procedures and technical rules to ensure industrial safety
- To establish specialized forces and appropriate means to actively deal and tackle the consequences quickly when incidents occur
Proposal selection exhaust gases treatment technology for Can Thep Thai Nguyen Factory:
A survey conducted at the Can Thep Thai Nguyen factory in March 2015 revealed a concerning increase in emissions of NOx, NH3, and dust from the kiln stack over the years To address this issue and ensure compliance with permitted standards, it is crucial to implement appropriate remedial measures for kiln stack emissions in the near future.
Proposal NOx treatment technologies for kiln stack
The installation of an SNCR system in kiln stacks is essential for effectively controlling NOx emission levels This advanced technology allows for significant reductions in NOx emissions, achieving levels as low as 800 mg/Nm3, eliminating the need for additional treatment systems Furthermore, incorporating an SNCR system can also help minimize dust dispersion into the atmosphere, enhancing overall environmental compliance.
Figure 4 6- Diagram of SNCR technology (Source: Report on status of air quality in Hon Chong Xi Mang Company)
DISCUSSION AND CONCLUSION
5.1.1 The current situation of air in Can Thep Thai Nguyen factory?
The environmental quality in the research area is predominantly satisfactory, with most analyzed indicators meeting the permissible standards set by Vietnamese regulations Furthermore, the calculated values comply with ISO standards for industrial environments, and the handling equipment adheres to modern environmental standards as specified by TCVN.
The plant invested properly for installation of some waste handling equipment and modern to ensure TCVN of environment as well as measures to ensure safety and prevent environmental incidents
5.1.2 The possible management and technology solution to reduce air pollution of the Can Thep Thai Nguyen factory?
The factory has effectively implemented environmental protection measures and meets most requirements; however, to enhance its efforts, it must install a new exhaust gas treatment system for kiln stacks, as their emission capacity is increasing over time.
NO2 processing system and bag filter equipment should be installed to ensure respective emission standards, and contribute to better environmental protection
The study concluded with notable limitations, including potential air quality impacts from nearby factories due to their proximity to the Can Thep factory Additionally, the results were derived from a brief three-month period, and as Can Thep is a small branch of TISCO, the findings may not be representative of the entire company.
Based on preliminary research and technology analysis of the Can Thep Thai Nguyen factory, we recommend actions to mitigate both the negative and positive environmental impacts of the project.
The pervasive issue of pollution serves as a wake-up call for factories, their employees, and environmental protection authorities alike Urgent action is required to combat air pollution through comprehensive and effective solutions.
The factory is being implemented environmental management system ISO
Thai Nguyen Steel Joint Stock Company emphasizes the importance of enhancing education on safety, industrial hygiene, and environmental protection Regular inspections and supervision of procedures and technical regulations are crucial to ensure industrial safety Additionally, the Can Thep Thai Nguyen factory should establish specialized teams and appropriate resources to effectively address and manage consequences promptly in the event of incidents.
The main Port of Thai Nguyen JSC
The Kiln Stack of factories
Anh, N.B (2013) Pollution from the steel industry: Who is responsible for pollution Jounal of Labour
Bac Ninh monitoring stations Report on Environmental Impact Assessment in rolling steel factory of Dat Phat Company (pp 32-47)
Can Thep Thai Nguyen factory retrieved from://tisco.com.vn/f=Company&p=5&id (accessed on 10/3/2015)
Co, H.K & CTV Environmental techniques Technical science publisher Hanoi
Cuong, P.H (2015) Industrial development accompany with environmental protection
Institute for policies and development
Dang, P.N (2003) The air environment Ha Noi Science and Technology Publisher
Environmental monitoring report in Nhon Trach 5 industrial zone, Nhon Trach, Dong Nai province
I don't know!
Institute of information technology– Ha Noi national university (2013) Controlling air pollution Journal of Science And Technology
J Environ Sci Eng (2011 Oct) Assessment of air quality in and around a steel industry with direct reduction iron route Handbook of resource, 53(4), pp 437-42
Noise and vibration in production Journal of Occupational Safety, 8 (2)
Report on status of air quality of Hon Chong Xi Mang Company