Đồ án xử lý khí thải gạch men

Xử lý khí bụi và khí SO2 từ quá trình sản xuất gạch men

HO CHI MINH CITY UNVERSITY OF TECHNOLOGY

FACULTY OF ENVIRONMENT AND NATURAL RESOURCES

PROJECT WORK:AIR POLLUTION CONTROL FOR ENGINEERING

DESIGN PARTICULATE MATTER TREATMENT

Ho Chi Minh, August 2021

Instructor Assoc Prof Nguyen Nhat Huy Members

1. Chu Hoang Minh – 1752340

2. Nguyen Ngoc Huy – 1752233

In advance of proceeding with the content of this report on Project Work: Air PollutionControl Engineering, we would like to express our deepest appreciation to all those whoprovided us with the possibility to complete this report We would like to appreciate and give our

special gratitude to Assoc Prof Nguyen Nhat Huy, who worked a great deal, gave us advices,

feedback and provided us with lots of foundation knowledge so that we couldunderstand what we were written and drawn in this project work Furthermore,our sincere appreciation goes to the team whose advisory and guidance was crucial during thecourse of the project Without their help, we would not have accomplished thischallenging project work, which is very important section of our final markresult

However, this project work could have some mistakes We hope our adviserwill give suggestions and corrections to help the knowledge in this project bemore complete

Finally, once again, we would love to express our deeply gratefulness to ourinstructor Mr Nguyen Nhat Huy who helped us get better our understandingabout the Air Pollution Control Engineering The time we spent was veryenjoyable, we have also learned many useful things which would support us

a lot for our future career We will strive to utilize and improve this gained knowledge inthe best possible way

Ho Chi Minh,

Hoang Minh CHU – Ngoc Huy NGUYENTable of Contents

List of Tables

List of Figures

PROBLEMS FOR PROJECT WORK

1 Task (content requires original data)

Data of the influent gas for treatment is defined:

• Industry: ceramic tiles manufacturing process

• Pollution: dust and toxic gases

• System efficiency ranges from 85% to 95%

• Need to satisfy national regulation QCVN 192009/BTNMT

2 Content of explanatory and calculation parts

Students follow the requirements of the outline for the technical subject ofAir Pollution Control Engineering, specifically as follows:

• Select and explanation of technology process for treatment

• Design systems for treatment: calculation and demonstrating for the details of operation

• Select and calculate ancillary equipment

• The concentration of these pollution after influent air passing throughtreatment process

3 Drawings and graphs (type and size of drawings)

• Process flow diagram: 01 with size A3

• Wet scrubber: 01 with size A3

• Tray tower scrubber: 01 with size A3

CHAPTER 1: INTRODUCTION

In modern life, the increase of urbanization and modernization has served and contributed to thequality of human life However, this also results in the environmental degradation including air

human activities has been become one of the most serious concerns around the world anddirectly posed a serious threat to human health In fact, The Environmental Performance Index(EPI) of the US places Vietnam in 115th place out of 180th economies, citing its air pollution andmodest biodiversity protection Furthermore, according to Health Environment ManagementAgency, said: “WHO figures show that six out of the ten diseases with the highest mortality rates

in Vietnam are related to air pollution.”

In the past few decades, in Vietnam, with the development of science, technology andurbanization, it has caused environmental pollution due to the lack of treatment of exhaust gas,wastewater and solid waste One of the issues that is concerned is the increasing emissionsemitted into the environment every day from industrial activities Vietnam is one of the countrieshas the highest air quality index in Asia and the World, especially in Hanoi and Ho Chi Minhcity But the current situation is not decreasing but increasing, especially from industrialactivities such as ceramic tile production, which not only pollutes but also harms human healthfrom the release of fine dust and toxic gas These are compounds harmful to human health,causing some forms of cancer The problem is how to solve the issue of emissions at the ceramictile factory most effectively emitting into the environment; besides, it must be economicallyappropriate and not cause negative impact on the environment

1.1 Contamination and hazard from ceramic tiles manufacturing

In this project of Air Pollution Control Engineering, ceramic tiles manufacturing would be usedfor case study Currently, the demand for bricks in Vietnam as well as in other countries aroundthe world is huge for serving accommodation need for people Along side with the increasing ofpopulation, the demand for housing is more and more necessary Therefore, the ceramic tiles areindispensable material in the construction such as schools, hospitals, condominiums, high-risebuildings However, today the ceramic tile production from process generate a large amount ofboth dust and toxic gas that negatively affect human health and the surrounding environment

1.1.1. Dust

Ceramic tiles are made from a combination of clays, feldspars and other natural occurringminerals, mixed and grinded in water and fired in a high temperature kiln Dust generated fromthe ceramic tiles process is of varying sizes As a final inert product, they contain mostly afraction of cement and silica dust which is one of the productions of workplace mechanical

processes such as crushing, cutting, drilling, grinding, sawing or polishing of natural stone.These respirable dust particles is released as an fine dust (), which are small enough to penetratedeep into the lungs and can cause irreversible lung damage of human or animal and reducing thephotosynthetic capacity of ecological systems

Table 1-1: Characteristic of dust from ceramic manufacture [1]

Table 1-2: Particles size distribution from ceramic tiles manufacturing [2]

Dust in the production of ceramic tiles mainly generates from these following producing stages:

• Transport of raw materials from tank to crusher

• Handling and storage the products

• Surface polishing stage of ceramic tiles

• The process of burning bricks with FO and DO oil from the furnace

Table 1-3: Typical concentration of dust pollution in the ceramic tile manufacturing industry [1]

Manufacturing processes Concentration of

Dust (mg/)

Concentration (mg/)

QCVN 19:2009/BTNM

T

Transport of raw materials 280

Handling and storage 527

Surface polishing stage 970

Burning bricks from furnace 944.2

1.1.2. Toxic gases

There are also many toxic gases that cause greenhouse effect and lead to the climate change,such as: mainly due to burning bricks with FO oil contained 3% of S from the furnace Thesegases are seriously toxic to the surrounding air environment and effect negatively on humanhealth: pneumonia, lung cancer …

Table 1-4: Parameters of the emissions from furnance [2]

Manufacturing processes Gas pollutants Concentration (mg/) 19:2009/BTNMT QCVN

Burning bricks from

furnace

Therefore, it is necessary to have an appropriate treatment system to prevent the harmful effects

of dust and toxic gases on the surrounding environment Moreover, using approved respiratorswhenever engineering controls are not effective to keep the dust, and particularly the crystallinesilica dust and toxic gas includes , which would be a threat to breath, lung cancer and reducingthe photosynthetic capacity of ecological systems, must be belowed the exposure standards

1.2 National regulation

This project in treating quality of dust expects to have the effluent meet the type B of theregulation of Vietnam Standard QCVN 19: 2009/BTNMT on Industrial Emission

Table 5-5: National technical regulation on industrial emissions QCVN 19: 2009/BTNMT

CHAPTER 2: AIR POLLUTION CONTROL METHODOLOGY

FOR CERAMIC-TILES MANUFACTURING

The production of ceramic tiles can generate both toxic gas ( and particulate pollution (cementand silica dust) As mentioned above, airborne matter particles in ceramic manufacturing areemitted from three main processes: toxic gases are emitted mostly in burning brick process anddusts are mainly relieved from transportation of raw materials, cutting and molding, surfacepolishing stage

2.1 An example for air polution control procedures of ceramic tiles companies

There are some well – known ceramic tiles factories in Vietnam, the following companies are thereference for the current leading Vietnamese ceramic tiles such as Hoa Phat, Hoa Sen or DongTam Ceramic Tiles,… Along with economic development, the above companies must satisfy theregultion of emission standards by applying technology diagrams from environmental company

Figure 2-1: Typical procedure for air pollution control

Ngoc Lan company

ETC– Environment comapny

Au Lac company

Tin Dat company

2.2 Air pollution control technologies for ceramic tiles manufacturing

2.2.1. Cyclone (dry scrubber)

Cyclone separators or simply cyclones are separation devices (dry scrubbers) that use theprinciple of inertia to remove particulate matter from flue gases Cyclone separators is one ofmany air pollution control devices known as pre-cleaners since they generally remove larger

pieces of particulate matter In addition, several cyclone separators can operate in parallel, andthis system is known as a multicyclone.

It is important to note that cyclones can vary drastically in their size The size of the cyclonedepends largely on flue gas flowrate, thus larger operations tend to need larger cyclones Thereare three types of cyclone includes: standard cyclone, stairmand cyclone and swift cyclone that

we can use for different size of dust

Figure 2-2: Schematic of Cyclone [3]

Once polluted air pass through the inlet and move downwards to form an outer vortex flow,particles inside the influent were thrown into the cyclone body by centrifugal force After thatthese particles drop and out of the cyclone to collection equipment based on the propulsive force

of the eddy and gravity The fresh air flow began to reverse upward to form an inner vortex flowand discharge to the environment after approaching the base of cone section

2.2.2. Fabric Filter

Fabric filtration is a process which permits gas contains solids pass through a porous fabricmedium and retains particle matters Once air and dust pass through the filter cloth, the dustparticles larger than the gap between the fibers will be retained on the fabric surface according tothe sieve principle while the smaller particles adhere to the surface of the filter cloth by collision,

gravitational force and electrostatic attraction The collected dust gradually thickens up to form afilter aid film, which holds all very small dust particles

Figure 2-3: Schematic of Fabric Filter [4]

After operating time; the dust layer will be very thick, making membrane resistance efficiently.Fabric filter have to stop letting the exhaust gas pass through and proceed to remove the dust onthe bag house We choose three ways to reverting filterability includes mechanical, compressedair and gas cleaning The gas after passing through the fabric bag filter will be released to the air.The filtration efficiency reaches 99% and traps all very small particles based on filter aid

Table 2-6: Velocity of dust filtration [4]

Type of dust

Velocity of dust filtration (m/min)

Mechanicalcleaning Compressed air cleaning Gas cleaningCement & Silica dust 0.7 – 0.8 2.0 – 3.5 0.6 – 0.9

Table 2-7: Air filter bags for dust collector [4]

2.2.3. Venturi scrubber

Venturi scrubber aims to treat fine dust which is continued going through the centrifugal fan tothis wet filter machine In this machine, the dust flue gas flows at high speed and they collidewith the absorbent to form very small dust particles or even partly toxic gases After beingwashed, the heavy dust particles will fall inertia into the wet sump and be treated

Figure 2-4: Schematic of vennturi srubber [4]

2.2.4. Adsorption and absorption tower

The toxic gases after passing through the adsorption tower satisfies QCVN 19: 2009/BTNMT

Table 8-3: Comparision between absorption and adsorption

Definition

the molecules will be entirelydissolved or diffused in theabsorbent to form a solution

atoms pass through or enter a

bulky material

Volume of liquid

Solid surface area,Characteristics of solid

Products Steam & Wastewater Heat & Non reuse adsorbent

Figure 2-5: Schematic of absorption and adsorption tower respectively [4]

CHAPTER 3: SELECTION OF AIR POLLUTION CONTROL PROCESS FOR CERAMIC-TILES MANUFACTURING

3.1 Selection of technology for air pollution control

There are two main proposed treatment lines for the treatment of air pollution from ceramic tiles

Diagram 1 – the properties of particle pollution in ceramic tiles manufacturing mostly contains

fine dust The combination of cyclone and fabric filtration which is a dry treatment method could

be used for dust control First cyclone application aims to remove dust with size larger than 10and act as a pre-collector before the fabric filter collects dust with a particle size of less than 10.After that, adsorption is used to treat the polluted gas emission

Diagram 2 – This flue gas treatment system has replaced Fabric Filtration with Venturi Scrubber.

This Venturi Srubber which is a wet treatment method could be indiscriminately used for finalstage of dust control, while also efficiently treating the toxic gases emitted from the ceramic tilesmanufacturing before entering toxic gases to the absorption tower and finally relieving clean air

to the environment

As mentioned, there are two proposed treatment lines for the treating toxic gases and dust fromceramic tile manufacturing The main difference between these two treatment lines are thetechnology to eliminate dust (cement and silica dust) from manufacturing processes betweenfabric filter – venturi scrubber and technology to eliminate toxic gases adsorption – absorption.

Table 3-9: Comparision between fabric filter and venturi scrubber

Venturi scrubber in this case study is used for dust control instead of fabric filter The reasonswhy we choose the wet scrubber for treating dust are:

• High efficiency for dust size less than 5 accounted for largest inlet concentration

• Applicable for silica dust with size of 0.01

• Application for high temperature of influent form furnace

• Simultaneously removal of both silica dust and a part of gas pollution

• Simple structure and small installation space

Figure 3-6: Schematic of Venturi Scrubber

Burning brick along with FO (3% S) from furnance release pollutant components including , ,and ash In ceramic tiles furnace, the concentration of always exceed the national regulation andneed to be treated before relieving to the environment

Table 3-10: Comparision between absorption and adsorption for toxic gases treatment

1 Heat steam and cold water is available

2 Exhaused gas has a realitively high

concentration of

3 Efficiency 85 – 90%

1 High cost for reconstitution

2 High cost equipment due toworking in corrosive environment

3 Efficiency 90 – 95%

To implement adsorption method for treating , large investment cost is required for materials tomanufacture equipments that be able to work in highly corrosive environments and at hightemperatures Therefore, our group applying absorption for this project The absorbent in thisproject is and lime is not appliciable because deposits clogged the device

Plate column is used for gas treatment, the reasons why we choose this absorption system are

• Suitable for high inlet capacity 63000 and high efficiency

• Simple equipment, low energy consumption, pressure drop and operating costs

• Less affected by corrosive environment than others

Figure 3-7: Schematic of Plate Column

3.2 Operating technology diagram for air pollution control

Firstly, dust is collected at the arising position through the air hoppers arranged in the stages ofdust generation and gas emissions The air hoppers are connected to the air ducts and flew intothis system by centrifugal fan Secondly, dust are priority to reduce based on wet treatmentmethod by using venturi scrubber Then, the combination of dust and water can be separated bycyclone separator to make sure that concentration of dusts from flue gas can be treatedefficiently Finally, plate column is used to treat toxic gases contained for satisfying QCVN192009/BTNMT

Table 3-11: Technology process diagram