Conceptual_Design_Report_Bac_Ninh_WtE_Project

REPORT

115002070
June 16, 2019

CONCEPTUAL DESIGN REPORT
Bac Ninh WtE Project


115002070
Bac Ninh WtE
Conceptual Design Report
i

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reproduced without permission in writing from Pöyry Switzerland Ltd.

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Conceptual Design Report
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Internal document control

Client

Thang Long Energy and Environment Joint Stock

Company
Conceptual Design Report
Bac Ninh WtE Project

Title
Project
Phase
Project No.

115002070

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Drawing/Reg./Serial No.
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File location
System

Conceptual Design Report 115002070_clean.docx
Microsoft Word 16.0

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Responsible BU

Revisions:
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Copyright © Pöyry Switzerland Ltd.

14/06/2019
Ilkka Lassila, et. al. / WtE/process specialist
15/06/2019
J. de Beer / Proj. Manager


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Conceptual Design Report
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Preface

Contact:
Jacques De Beer

Pöyry Switzerland Ltd.
Hanoi Representative Office
5A Floor BIDV Tower
194 Tran Quang Khai street,
Hoan Kiem district,
Hanoi, Vietnam
Tel. +84 (24) 3974 8388
Fax +84 (24) 3974 1199
E-mail:

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Conceptual Design Report
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Preface
Contents
1

INTRODUCTION

1

2

BASIC CONCEPT

2

3

DESIGN BASIS

3

3.1
3.2
3.3
3.3.1
3.3.2
3.3.3
3.4
3.5
3.5.1
3.5.2
3.5.3

Site Location
Site Layout and Equipment Arrangement
Site Conditions
Soil Conditions
Climatic Conditions
Seismic Conditions
Reference Design Conditions
Fuel
Municipal Solid Waste (MSW)
Pollutants Concentration

Fuel Oil Analysis

3
3
4
4
4
4
5
6
6
7
8

4

BOILER PLANT CONCEPT

9

4.1
4.2
4.3
4.4
4.5
4.6
4.6.1
4.6.2
4.6.3
4.6.4

4.6.5
4.6.6

General
Steam Generation
Fuel Oil Firing System
Draft Plant
Boiler Pressure Part
Emissions
Emissions Limits
NOx Emissions
Acid Gaseous Emissions
Particulate Emissions
Dioxin and Furans Emissions
Heavy Metal Emissions

9
10
10
11
11
13
13
15
15
15
15
15

5

TURBINE GENERATOR PLANT

16

5.1
5.2

Condensing Extraction Turbine
Condensing Plant

16
16

6

BALANCE OF PLANT

17

6.1
6.2
6.3
6.4
6.5
6.6

Waste Storage Requirements and Volumes
Waste Handling
Ash Collection and Removal

Ash Disposal Considerations
Water Supply
Water Treatment

17
19
20
20
21
22

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6.7
6.8
6.9
6.9.1
6.9.2
6.9.3
6.9.4
6.10
6.10.1
6.10.2
6.10.3

6.10.4
6.10.5
6.10.6
6.10.7

Demineralization Plant
Waste Water Treatment
Electrical Works
22kV MV Substation
11kV STG Power Generation System
690V Power Distribution System
400V Power Distribution System
Instrumentation and Control
Distributed Control System (DCS)
Programmable Logic Controllers (PLC)
Steam Turbine Governing, Protection and Supervision
Boiler Safety Related System (SRS)
Emissions Monitoring System
RDF Plant
General Field Instrumentation

22
23
23
23
23
23
24
24
24

24
25
25
26
26
26

7

CIVIL AND STRUCTURAL WORKS

27

8

HEAT AND MASS BALANCE

28

9

WATER BALANCE

29

10

EPC COST ESTIMATE

30

11

O&M COSTS

30

11.1
11.2

Fixed costs
Variable costs

30
31

12

PRELIMINARY TIME SCHEDULES

32

Annexes
Appendix 1
Appendix 2
Appendix 3
Appendix 4
Appendix 5
Appendix 6
Appendix 7

Appendix 8
Appendix 9
Appendix 10
Appendix 11

Process Flow Diagram
Plant Layout
Climatic Conditions
Preliminary Soil Investigation Report
Fuel Analysis
Raw Water Quality
Overall Single Line Diagram
Heat Mass Balance Diagram
Water Balance Diagram
Preliminary Project Time Schedule
Comparison of grab cranes versus front end wheel loaders

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List of Tables
Table 3-1 Fuel Analysis Hanoi .......................................................................................................... 6
Table 3-2 Fuel Sample Calorific Value .............................................................................................. 6
Table 3-3 Valmet requirement ........................................................................................................... 7
Table 3-4 BMH Waste Specification ................................................................................................. 7

Table 3-5 Fuel Oil Quality ................................................................................................................. 8
Table 4-1 Emission Limits# ............................................................................................................. 13
Table 6-1 Water Demand ................................................................................................................. 21
Table 8-1 Heat Balance Analysis ..................................................................................................... 28
Table 9-1 Water Balance Analysis ................................................................................................... 29
Table 10-1 EPC Cost Estimates ....................................................................................................... 30
List of Figures
Figure 3-1 Project Location .............................................................................................................. 3
Figure 3-2 Map of strong earthquake originated zones and maximum shake zoning .......................... 4
Figure 3-3 Seicmic Zone and Maximum seismic intensity zone of Vietnam (TCVN 9386-2012) ...... 5

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Abbreviations
HBD
IW
MSW
RDF
WBD

Heat Balance Diagram
Industrial Waste
Municipal Solid Waste
Refuse Derived Fuel

Water Balance Diagram

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1

INTRODUCTION
Thang Long Energy and Environment Joint Stock Company is developing a Waste to
Energy (WtE) plant capable to process 500 tons per day of Municipal Solid Waste
(MSW) and an additional 100 tons per day of Industrial Waste (IW) located in Que Vo
district of Bac Ninh Province, approximately 55 km from Hanoi, and producing around
10 MW net electricity exports to the EVN distribution system.
The objectives are to:
(a) Develop a WtE Plant having a dependable capacity of about 10 MW net power
output and an incineration capacity of 500 t/d municipal waste disposal and 100 t/d
industrial waste disposal. The project will also include, –among others, the design
and construction of the fresh water supply system for the WtE Plant from a nearby
river, and the construction of overhead power lines to evacuate the power to the
adjacent EVN 22kV transmission line;
(b) Place a turnkey fixed lump sum price EPC contract with a qualified contractor; and
(c) Own and operate the WtE Plant from the Commercial Operation Date.

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2

BASIC CONCEPT
The concept of the project is to develop a WtE Plant of about 10 MW net power output
and an incineration capacity of 500 t/d MSW and 100 t/d IW.
The WtE Plant shall have one Circulating Fluidized Bed (CFB) boiler and Refuse
Derived Fuel (RDF) preparation plant with the associated waste receiving and storing
system.
CFB boilers combined with adequate flue gas treatment have been selected to fulfil the
Vietnamese regulatory requirements for stack emission limits as stated in greater detail
later in this document.
The boilers shall be designed to burn RDF produced from MSW and IW only.
The WtE Plant will be connected to the EVN 22kV power grid.
Raw fresh water shall be drawn from a river adjacent to the site.
The preliminary process flow diagram is shown in Appendix 1 [Process Flow Diagram].

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3

DESIGN BASIS

3.1

Site Location
The proposed Site for the plant is located in Que Vo district of Bac Ninh Province,
approximately 55 km from Hanoi.
The Site is located in a general flat area and small hills. However the middle of the area
has formed a water pond. The area elevation is generally from around 2.0 m to 3.5 m
and around 0.0 to -1.0 m at the water pond. The project location is shown in Figure 3-1
below.

Figure 3-1 Project Location

The project site will be located in the area with the reference coordinates:
N 21o09’33”
E 106o14’04”
The Cau river runs along the north-western side of the site.
3.2

Site Layout and Equipment Arrangement
The Plant shall be located near the Cau river bank which shall include space for the
waste truck operating/receiving platform, waste bunker, waste separation, RDF
preparation and storage, power plant island, office building and water treatment plant,
covering a total area of about 4.834 ha. The waste which is foreseen to be treated in the
facility is stored in an enclosed bunker adjacent to the boiler.
The general plant layout provided in this report Appendix 2 [Power Plant - Layout]
suggests preliminary location for the boiler, turbine, waste receiving, RDF fuel

preparation and ash handling with storage systems, water treatment system and the
major buildings.

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3.3

Site Conditions

3.3.1

Soil Conditions
The Consultant carried out a site visit on 29 May 2019 by a team of specialists drawn
from the Consultant’s Bangkok and Vietnam office. At the time of site survey, the
proposed site location was mostly covered by bushes, vegetation and cattails. Some low
spots and swamp could be found at the proposed power plant area. The Owner is
currently filling some parts of the site with river sand from original land surface to an
elevation varying between +1.0 m and +2.0 m at the proposed office area. The
compaction is not being controlled as the sand is deposited.

3.3.2

Climatic Conditions
The Annual Mean Temperature averages 25° C with monthly maximum temperatures of

30,7° C and monthly minimum temperatures of 14.9° C.
Further details are provided in the Appendix 3 [Climatic Conditions].

3.3.3

Seismic Conditions
The Consultant considers the project site to have medium risks of earthquake as the
northern part of Vietnam is located in a region of moderate seismic hazard. There have
been some significant earthquakes recorded in the area nearby the site as shown in
Figure 3-2 below. The closest and most severe being the Tuan Giao earthquake (24th
July, 1983) with a 5.3 magnitude at a depth of 13 km, about 400 km northwest of Bac
Ninh .

Figure 3-2 Map of strong earthquake originated zones and maximum shake zoning

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According to "Earthquake Zonation Map on Vietnamese territory" and Design of
structures for earthquake resistances standard (TCVN 9386-2012), Que Vo - Bac Ninh
is located in the area subjected to category VIII (MSK-64) having Peak Ground
Accelerations (PGA) of 0.1226 as depicted in Figure 3-3 below.

Figure 3-3 Seicmic Zone and Maximum seismic intensity zone of Vietnam (TCVN 93862012)

The WtE Plant shall be designed for seismic loads according to Vietnamese Seismic
Code Zone which is approximately equivalent to UBC97 Zone 2A using Z = 0.19 as
recommended in the Geotechnical Investigation report. Further details are provided in
the Appendix 4 [Geotechnical Investigation Report].
The Contractor shall confirm the seismic category and the design requirements that
must be adopted for the site.
3.4

Reference Design Conditions
The reference design conditions are as follows:
Ambient air temperature (dry bulb)

25˚C

Relative Humidity

70 %

Atmospheric pressure

1,015 mbar

Makeup water temperature

25˚C

Fuel temperature

25˚C

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3.5

Fuel

3.5.1

Municipal Solid Waste (MSW)
The fuel for the proposed power plant is MSW and industrial waste (IW) for which
neither the sourcing nor the composition has been identified.
Fresh MSW will be provided to the plant in the amount of 500 t/d of fresh waste and
100 t/d of industrial waste. The fuel analysis of waste was made by several parties and
is summarized in Table 3-1 and Table 3-2 below:
Table 3-1 Fuel Analysis Hanoi
Samples
Material
Food
Paper
Diaper
Plastics
Fabrics
Wood
Garden

Rubber
Metals
Inorganic
Hazardous
Stone
Debris
Total

Unit
%m
%m
%m
%m
%m
%m
%m
%m
%m
%m
%m
%m
%m

Cau Dien
4 Samples
53.04
4.53
11.94
13.59
2.36

0.79
3.26
.56
0.39
1.77
0.06
3.03
4.77
100.09

Nam Son
8 Samples
52.57
4.6
12.7
17.36
4.83
0.88
1.47
0.62
0.27
0.97
0.3
1.37
2.08
100.02

Xuan Son
4 Samples
46.09

3.73
12.58
20.27
5.41
0.52
4.04
2.63
0.62
0.87
0.24
1.41
1.61
100

Table 3-2 Fuel Sample Calorific Value
Moisture
Ash
C
H
O
N
S
Cl
Total
LHV
LHV

Sample
%
%

%
%
%
%
%
%
%
kcal/kg
kJ/kg

Cau Dien
60.79
9.3
43.78
6.22
23.75
1.66
0.18
0.61
85.5
1,293
5,412.5

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Nam Son
59.01
10.37
48.64
6.43

17.25
1.68
0.34
0.63
85.34
1,174
4,914.4

Xuan Son
54.76
11.61
41.07
6.53
24.73
1.66
0.25
0.46
86.31
1,315
5,504.6

Hanoi JICA
4 Samples 4 Samples
63.2
68.7
5.3
5.1
7.3
2.5
7.2

8.9
0.9
1
0.6
0.4
3.2
2.6
0.2
0.3
0.9
0.6
1.6
1.4
0
0
0.4
0.4
9.1
8.1
99.9
100


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The proposed boiler supplier for the project, Valmet, has indicated a typical fuel analysis
for the mixture of RDF with an analysis as shown in Table 3-3 below:

Table 3-3 Valmet requirement
Valmet
Moisture
Ash
C
H
O
N
S
Cl
Total
kcal/kg
kJ/kg

50
14.2
49.6
5.2
28.64
1.4
0.17
0.77
150.1
1,911.1
8,000

Steam Pro
33.3
9.5
33

3.5
19.1
1
0.1
0.5
100
1,911.1
8,000

The above figures in the column ST Pro have been recalculated to 100% total for all
components. These figures are roughly in line with the “BN Finland” waste analysis as
well as a JICA report which indicated LHV values of between 6,300 kJ/kg 8,250 kJ/kg.
The proposed RDF plant supplier for the project, BMH, has given a specification for the
waste input to the separation plant, but there is no data for the expected RDF output as
shown in Table 3-4 below.
Table 3-4 BMH Waste Specification
Waste Input
BMH
Min Req
Bio-degradable
50 %
Plastic
6%
Tires – rubber
2%
Textiles
2%
Inert (glass, stone)
10 %
Moisture

55 %
Density

45 %
10 %
1%
1.5 %

400 – 600 kg/m3

In order to make a prediction of waste availability and expected waste analysis
considering the various waste streams, recommend that the Owner undertakes a further
campaign of sampling and sampling to better define the quality of the MSW. Sampling
should be done at the various locations proposed as supply source for the plant.
We also suggest that further clarifications with BMH are required to gain an
understanding of the quality of RDF after the separation process. Furthermore, data
about the flow and analysis of the industrial waste is required as to date no information
or data has been made available to the Consultant.
3.5.2

Pollutants Concentration
Valmet has indicated in its proposal that the maximum chloride levels acceptable in the
RDF are 1%. In some of the analysis data provided by the Owner it appears that this
value is exceeded. In addition, since Industrial Waste may have higher values, and

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neither the analysis nor the source of the Industrial Waste is defined, we wish to point
out that this could be a contentious issue and requires further analysis.
3.5.3

Fuel Oil Analysis
Light Fuel Oil (LFO) shall be used for starting up the boiler until the bed material
temperature is above 850 oC before starting feeding RDF into the furnace.
The expected quality of fuel oil is shown in Table 3-5 below.
Table 3-5 Fuel Oil Quality
Light Fuel Oil - Characteristic
Density (at 15 °C)
Lower Heating Value
Sulphur content (max)
Carbon residue
Ashes
Flash point (min)
Pour point (max – tank location outside)
Viscosity (at 40 °C)

Unit
kg/m3
MJ/kg
%w
%w
%w
°C
°C

mm2/s

Value
800 – 920
42 – 43
< 0.2
< 0.3
< 0.01
> 60
< -20
1.5 – 3.4

The use of LFO is only necessary during start-up and low load operation to maintain the
required furnace temperature and retention time. In normal operation of the boiler there
will be no consumption of the LFO.

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4

BOILER PLANT CONCEPT

4.1

General
The specific design requirements for mechanical components are presented below for
the supply of one (1) complete Circulating Fluidized Bed (CFB) boiler for a WtE Plant
with approximately a 12 MW nominal gross power output steam turbine/generator. The
CFB shall be designed for the combustion of Refuse Derived Fuel (RDF) produced
from Municipal Solid Waste (MSW) and Industrial Waste (IW). The purpose of mixing
IW to MSW is to maintain the minimum required heating value of the RDF (8 MJ/kg) to
the boiler.
The boiler shall be a sub-critical drum type single pass horizontal boiler designed as a
single drum boiler with natural circulation and gas tight welded membrane walls, and
shall have the capacity necessary to ensure that the associated steam turbine generator
shall always be capable of delivering the TMCR net power output over the full specified
range of climatic conditions and fuel quality throughout the design life of the plant,
including due allowance for unavoidable degradation of the performance of the plant
that will occur despite operation and maintenance of the plant in accordance with the
manufacturer’s instructions.
The boiler will be hung/supported from the top of the boiler structural steel columns,
which are included in the Works. The steel structures will be founded to the ground
level.
The membrane wall structure of the complete combustion chamber is covered with
refractory lining. Water circulating in the furnace wall piping cools down the structure
and fireproof mass protects the wall material from overheating and sustains high enough
temperature for combustion.
Sand shall be fed to the boiler from a silo to maintain the necessary bed material level in
the furnace and cyclone. The make-up silo is filled from a truck by a pneumatic or bulk
material conveyor. Before CFB boiler start-up, the sand shall be filled directly from a
truck to the furnace.
The Works shall be designed and laid out to facilitate inspection, cleaning, maintenance,
repair and operation, with the reliability of power supply being the first consideration.
The design shall incorporate every reasonable precaution and provision for the safety of

all those concerned in the operation and maintenance of the Works.
The boiler flue gas velocity shall be minimised to avoid the erosion of superheaters,
economizers and other heat transfer surfaces. The residence time of the flue gases in the
furnace shall not be less than 2 seconds at 850 °C as the minimum combustion
temperature to ensure complete combustion and thus avoid formation of dioxins.
All materials shall be new and of best quality, and of the class most suitable for working
under the conditions specified for the boiler plant.
The Works shall be furnished with measuring equipment and actuators, which enable
reliable and safe continuous operation as well as automatic start-up and shut-down of
the equipment.

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4.2

Steam Generation
The boilers shall be designed to fire RDF having the range of properties specified in the
section 3.6 for extended periods at full load.
The boiler shall be capable of operating at any load between 80 to 100% BMCR for
extended periods over the full range of properties of the fuel, without the support of the
oil burners.
Boiler pressure parts shall be designed in accordance with international codes and
standards.
Associated instrumentation control and protection systems shall also comply with

recognized international standards and insurance requirements.
A boiler storage (conservation) system shall be provided for both short and long term
protection of the internal surfaces of pressure parts during periods of standby or shut
down.
The final superheater outlet steam temperature shall be maintained at the rated value
down to at least 85% MCR.
The steam quality at the boiler outlet shall meet the latest issue of the relevant
international standard and the specific requirements of the steam turbine manufacturer.
The WtE Plant shall be designed to facilitate safe and efficient start up from hot, warm
and cold conditions without exceeding permissible levels of stress within components.
It is anticipated that the normal pattern of operation will be to run base load normally at
85% to 95% load so as to allow the daily incoming MSW to be fully consumed. The
WtE Plant shall be designed to satisfy this requirement safely, efficiently and without
exceeding permissible levels of stress within components.
The WtE Plant shall achieve these requirements with adequate levels of redundancy and
flexibility to provide high availability as economically as possible. Annual average
through life availability, excluding major overhauls, is required to be not less than 92%.
Failure of any one item of auxiliary equipment shall not result in complete loss of the
boiler output or tripping of the related turbine generator. The design shall include
adequate duplication and/or diversification of power supplies.
The WtE Plant shall be designed for remote control and monitoring from a central
control room using a DCS. Full sequence control shall be provided to facilitate
automatic start up and shut down of the boiler and its auxiliary systems with minimum
plant attendance.

4.3

Fuel Oil Firing System
The boiler shall be equipped with a fuel oil firing system suitably sized for boiler startup and shutdown procedures and for low load operation of the boiler. The boilers shall
be equipped with a start-up firing system designed heat the furnace to 850 °C prior to

feeding waste into the furnace.
The fuel oil system shall fully comply with all the safety regulations and requirements
valid in Vietnam.

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Facilities shall be provided adjacent to each burner for oil burner maintenance and
cleaning. The area shall be suitably protected to prevent oil spillage. There shall be
adequate space provided for oil burner removal.
The boiler burners, the ignition system and the flame monitoring system shall be fully
compliant with the NFPA Code for boiler burners or an equivalent internationally
recognized code. Where an electronic programmable device is used for this purpose the
design should follow IEC 61508 or an equivalent internationally recognized Standard.
The firing system shall be fully automatic and supplied complete with oil piping, burner
elements, ignition burners and gas cylinders, flame detectors and safety shut-off valve.
Fuel oil ignition system shall be by high energy spark or with a propane gas ignition
system. Satisfactory ignition of the oil shall be obtained over the full range of air/fuel
ratios and combustion air temperature under all possible air flow regimes.
Flame detectors shall be fail safe and they must have a self-checking function. An
analogue signal of the main flame shall be provided for remote indication.
The monitoring and control of the burners shall take place in a dedicated and standalone
protection system which interfaces to the main control room DCS. The protection
system shall receive all necessary information to be able to purge the furnace, ignite,
shut off and control the burners and via the DCS to be able to report on all disturbances

in the system.
4.4

Draft Plant
The concept and arrangement of the combustion air system and induced draft system
shall be optimized. The optimization shall take into account the size of the plant for
reliability and maintainability of the plant with due consideration to plant redundancy.
Consideration shall be given to single fans, duplicate part load fans, combustion air fans
that will provide both primary and secondary air and whether there is an economic
justification to pre-heat the fluidizing air.
All fans shall be furnished with protection and control device and with all necessary
dampers and silencers. The dampers shall be motor operated.

4.5

Boiler Pressure Part
The boiler pressure parts shall be designed, manufactured, constructed and tested to the
current edition of international standards for boiler and WtE Plant design, manufacture,
construction and testing. Materials shall be those defined within the chosen
international design standards.
All headers, piping and tubing used in the boiler shall be fabricated from seamless
material.
Headers shall not be installed in the gas flow path.
The boiler pressure parts design life shall be a minimum of 240,000 hours. Appropriate
options shall be selected within the design code to ensure that the fatigue and creep life
of all components will be sufficient to accommodate the plant life. Pressure parts shall
be designed for adequate flow through all tubes and heating surfaces in order to prevent
overheating of any area under any load and all operating conditions. Additionally, flow

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rates and velocities shall be selected so as to avoid "departure from nucleate boiling"
(DNB).
There should be sufficient space between the sections of the boiler to allow access to the
heating surfaces for repair and maintenance. The surfaces shall be designed so that any
modifications and repairs can be performed within a reasonable time and costs.
The pressure parts of the boiler unit shall be cleaned in the factory before pre-erection
and shall be adequately protected against any internal fouling and condensation during
transportation and storage.
Headers shall be fitted with inspection nozzles suitable to allow for full visual
inspection and cleaning, the inspection nozzles should be mounted at the end of headers.
Closure of these openings should be by a full penetration butt weld and sufficient excess
material should be provided for future cutting and re-welding.
All headers which are designed on a time dependent basis shall be fitted with creep pips
or other means to allow periodic measurement of diametral creep distension.
All nozzles, branches and tube stubs shall be attached by welding and shall be of the set
on type. Set through type welds may only be allowed for large bore headers or drums.
The weld preparation and weld procedures shall ensure fully penetrating welds.
No nozzle, branch or tube stub weld shall encroach over the heat affected zone of
header or pipe main seam welds.
All nozzles, branches and tube stubs shall be of sufficient length to ensure adequate
access for welding on the adjoining tubes or pipes and to permit effective post weld heat
treatment of these butt welds so as not to affect the integrity of the drums/headers. Due
allowance shall be made for heat affected zones and maintenance access and repairs.

All branch connections to headers or pipes shall be executed with full penetration
groove welds.
Heat treatment of welded joints shall comply with applicable design standards.
The corrosion allowances for all main pressure parts shall be a minimum of 1mm for
carbon steel tubes and headers and 0.5 mm for alloy steel tubes and headers.
All boiler tubes shall be seamless and have a minimum supplied thickness of 3.2 mm
(0.125”), however in all cases the tube wall thickness shall exceed the code requirement
plus the corrosion allowance by a minimum of 10%. Tube thickness shall include
adequate provision for tube erosion and for thinning on tube bends. There shall be no
circumferential welds on tube bends.
The convective heat transfer surfaces shall have a proper spacing between tube loops
and platens, both transverse and back spacing in the direction of gas flow, to prevent
deposit formation and to ease cleaning.
Unless a more onerous test pressure requirement is specified in the boiler design code or
regulations, the boiler shall be hydrostatically tested after erection is complete to a
pressure equal to 1.5 times the boiler design pressure. The test gauge for recording the
hydrostatic test pressure shall be mounted at the highest point on the boiler. The high
pressure circuit from feed water inlet isolation up to the steam outlet isolation valve (or
turbine stop valve) shall be tested in a single test.

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4.6

Emissions

4.6.1

Emissions Limits
The below stated gaseous emissions (Table 4-1) are maximum limits applicable to all
load range between 80-100% for the whole ambient air temperature range specified in
Appendix 3 [Climatic Conditions] and for all fuel compositions defined in Appendix 5
[Fuel Analysis].
Table 4-1 Emission Limits#
No.
1
2

Parameters of pollutants
Total particulate matter
Hydrochloric acid, HCl

Unit
mg/Nm3
mg/Nm3

Concentration*
100
50

3
4
5

Carbon monoxide (CO)
Sulfur dioxide, SO2
Nitrogen oxide (NOx) (expressed as NO2)

mg/Nm3
mg/Nm3
mg/Nm3

250
250
500

6
7
8
9

Mercury and its compounds (Hg)
Cadmium and its compounds (Cd)
Lead and its compounds (Pb)
Total dioxin/furan (PCDD/PCDF)

mg/Nm3
mg/Nm3
mg/Nm3
ngTEQ/Nm3

0.2
0.16
1.2

0.6

# QCVN 61-MT:2016/BTNMT
* Reference condition : oxygen in the flue gas is 12%, dry, 0 °C and 1,013 bar(a).

According to the current emission regulations which apply to the incineration of
domestic waste it is a requirement that the temperature of the secondary combustion
chamber be  950 °C. In addition to this, the current emission regulations which apply
to the incineration of industrial waste require the temperature in the secondary
combustion chamber to be  1,050 °C. If the industrial waste stream contains organic
halogens (chlorine), the temperature requirement increases to a temperature  1,300 °C.
In respect of the proposed use of a Circulating Fluidised Bed (CFB) boiler for the Bac
Ninh Waste to Energy project, the above requirements pose a number of problems:
1. At a temperature of 950 °C or higher the CFB boiler will experience sintering of the
bed material. This will lead to boiler shut downs and subsequent low plant
availability.
2. In addition to the above problem, it is doubtful that with the low calorific value of
the RDF a temperature of 950 °C can actually be achieved.
3. In order to achieve a high enough Lower Heating Value (LHV) for the RDF, it is
intended to mix industrial waste in the final stage of producing the RDF. In terms of
the regulation this would require a temperature of 1,050 °C and in the case that the
industrial waste contains organic halogens, the required temperature increases to
1,300 °C. As this is a co-incineration facility, the question arises as to how this is to
be treated under the regulations as these do not appear to cover co-incineration
plants. From points (1) and (2) above, the temperature of 1,050 °C and 1,300 °C is
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problematic but is at the same time unlikely to be achieved given the heating value
of the RDF.
Chapter 4 of the current European Union Waste Incineration Directive 2010/75/EU
covers the requirements for waste incineration plants and co-incineration plants
incinerating solid or liquid waste. Article 50, clause 2 of the directive states:
Waste incineration plants shall be designed, equipped,
built and operated in such a way that the gas resulting
from the incineration of waste is raised, after the last
injection of combustion air, in a controlled and
homogeneous fashion and even under the most
unfavourable conditions, to a temperature of at least
850 °C for at least two seconds.
Waste co-incineration plants shall be designed, equipped,
built and operated in such a way that the gas resulting
from the co-incineration of waste is raised in a controlled
and homogeneous fashion and even under the most
unfavourable conditions, to a temperature of at least
850 °C for at least two seconds.
If hazardous waste with a content of more than 1 % of
halogenated organic substances, expressed as chlorine, is
incinerated or co-incinerated, the temperature required to
comply with the first and second subparagraphs shall be
at least 1,100 °C.
The previous directive, 2000/76/EC has the same requirements regarding temperatures.
In order for the proposed Bac Ninh Waste to Energy plant to be able to use CFB
technology to incinerate the Municipal Solid Waste and Industrial waste, technology
which is successfully used in plants in Europe, we would suggest the Owner to apply

the requirements of the EU directive 2010/75/EU instead of QCVN 61MT:2016/BTNMT and QCVN 30:2010/BTNMT. This would mean a temperature of at
least 850 °C is maintained for 2 seconds and in the case that the organic halogens in the
industrial waste exceeds 1 %, a temperature of at least 1,100 °C maintained for 2
seconds.
Based on the foregoing, however, it has to be noted that in reality the limitation of the
CFB boiler in terms of bed temperatures means that incinerating materials with an
organic halogen content of more than 1 % is not possible and this will somehow have to
be managed in the fuel receiving process.
Based on the foregoing, the following issues are therefore of importance in limiting and
managing the chlorine content in the IW:
•

A thorough understanding of the exact source of the IW;

•

A thorough understanding of the sources of chlorine in the IW (e.g. PVC); and

•

A clear understanding of the components in the IW which are not desirable in
respect of chlorine content.

This should be consolidated into a process and strategy for the management of the IW in
order to avoid issues with excessive chlorine content.
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4.6.2

NOx Emissions
The fuel used in this plant has fuel nitrogen content of 1.7% (maximum). In general the
fuel bound NOx production can be controlled by a controlled combustion temperature
(CFB bed temperature) and low oxygen combustion to reduce the conversion of fuel
bound nitrogen to about 3 to 4%
According to Vietnamese NOx Emission limit shall be maintained below 500 mg/Nm3
(12% O2, 0 °C). It is assumed that an SNCR system is not necessary for a CFB boiler
because of the low combustion temperature.

4.6.3

Acid Gaseous Emissions
The gaseous product from combusting waste fuel contains with HCl, HF, SO2 and SO3
that form acids when condensing or combining with the moisture in the air. The flue
gas cleaning system shall remove these gaseous emission by injection of a carbonate
compound into the stream of flue gas to adsorb these acidic gaseous compounds. The
reagent may be in the form of hydrated lime or sodium bicarbonate. The injection
system can be a dry, semi-dry or wet system. Hydrated lime is preferred over sodium
bicarbonate, mainly due to the resulting fly ash properties from the treatment process. If
sodium bicarbonate is used the fly-ash will be very soluble and needs to be stored in a
dry place.

4.6.4

Particulate Emissions

The particulate emissions from this plant are limited to a maximum of 100 mg/Nm3.
The two options to reduce particulate emissions are an Electrostatic Precipitator (ESP)
or a Fabric Filter Plant (FFP). The operation cost for the ESP are somewhat lower due
to lower pressure drop and hence lower auxiliary consumption, but the reduction
efficiency is also slightly lower as well. FFPs achieve the highest particulate removal
efficiencies and may be a better option when considering the possibility of installing an
injection of hydrated lime or sodium bicarbonate into the flue gas for adsorption of the
acidic gaseous components in the flue gas.

4.6.5

Dioxin and Furans Emissions
The dioxin and furans emission from this plant is limited to be less than 0.6 ng/Nm3.
The residence time of the flue gases in the furnace shall not be less than 2 seconds at a
minimum combustion temperature of 850 °C to ensure complete combustion and thus
avoid formation of dioxins.

4.6.6

Heavy Metal Emissions
Injection of activated carbon into the flue gas stream will remove the different kinds of
heavy metals typically resulting from the combustion of this type of waste material,
such as mercury, as well as of dioxins and furans.

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5

TURBINE GENERATOR PLANT

5.1

Condensing Extraction Turbine
The turbine generator will be a condensing extraction turbine with a design capacity of
about 12 MW.
The steam turbine shall be of a single-flow condensing turbine type connected to a
50 Hz, three phase A.C. generator.
The turbine shall be provided with steam extraction points for feed water pre-heating.
The number of feed heating stages shall be selected by the Contractor based on the
selected main steam parameters and the final feed water temperature.
The turbine itself shall be completely equipped, including steam admission emergency
stop valve(s), turbine control valves, feed heating steam line isolating valves and power
assisted non-return valves in feed heating and deaerator tank extraction steam lines.
Turbine vibrations shall meet the requirements of ISO 7919 Zone A for the shaft and
ISO 10816 Zone A for pedestals and bearings.
The turbine hall layout shall be such that at the major overhaul there is enough laydown area for all turbine components including turbine casings and also generator rotor.
The civil works design for the turbine building floor shall include allowances for the
weight of this equipment.

5.2

Condensing Plant
A water cooled condensing system with a wet cooling tower is the preferred solution.
The condenser and main cooling system are designed to condense 100% of the steam

flow under normal operation conditions.

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6

BALANCE OF PLANT

6.1

Waste Storage Requirements and Volumes
There will be two separate storages, one for the incoming MSW (and IW) and the other
one for the processed waste, RDF.
The required storage volumes have been calculated based on the assumption that MSW
is being delivered at a rate of 500 tons/day, each day of the year. IW delivery has been
assumed to allow breaks in delivery.
It has furthermore been assumed, based on the information from boiler supplier and
RDF plant supplier, that the longest required maintenance periods are:
RDF plant

10 days

Boiler plant 15 days
It has also been assumed that the maintenance breaks will be coincident, starting at the

same time.
MSW storage capacity
MSW is stored in a bunker with a 10 days storage capacity (determined by the RDF
plant downtime). It has been assumed that the bunker will be emptied before the start of
the maintenance period. During this period there would be no IW delivery to the plant
Assuming the bulk density of the MSW to be 400 kg/m3 the required storage volume is:
500 × 1000 × 10
400
𝑀𝑆𝑊 𝑠𝑡𝑜𝑟𝑎𝑔𝑒 𝑣𝑜𝑙𝑢𝑚𝑒 = 12,500 m3
𝑀𝑆𝑊 𝑠𝑡𝑜𝑟𝑎𝑔𝑒 𝑣𝑜𝑙𝑢𝑚𝑒 =

With the bunker bottom area of 35 meters wide and 40 meters wide, the height of the
waste pile would be approximately 9 meters onaverage.
The waste will be piled as shown in the picture below to allow the tipping openings to
be free for waste truck unloading. Due to this the top of the bunker is estimated to be
about 14 meters high, so that the overall bunker dimensions would be 35 X 40 X 14
meters.
If the development of the layout allows, the bunker could be narrower and longer to
optimize the costs for the waste crane, thus avoiding an overly long span.

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