Clutches and brkesSelect any 3 position random motion out of real world and d...
Thermal utilization (treatment) of plastic waste.
1. Seminar Paper on
Thermal utilization (treatment) of plastic waste
By
Deepjyoti Chakraborty (17MT001501)
Shreyas Agrawal (17MT001516)
Rupal Pande (17MT001584)
Kishore Kunal (17MT001690)
Om Prakash Rajak (17MT002263)
Environmental Science and Engineering Department
INDIAN INSTITUTE OF TECHNOLGY (INDIAN SCHOOL OF MINES) DHANBAD
2018
2. --- Contents ---
i. Introduction
ii. System modification
iii. Description of technology
iv. Test results
v. Economic aspects
vi. Conclusions
vii. References
3. Background and Motivation
• What are plastics?
• Advantages
• Global plastic production: Increased from 1.3 MT in 1950 to 245 MT in
2006.
• What is plastic waste?
• Plastic Disposal techniques:
Landfilling, Incineration, Recycling, Bio-degradation.
4. Background and Motivation
• Thermal treatment process- Incineration was adopted.
• Advantages of Thermal treatment process
• What is Thermal utilization installation?
• Research aspects:
1. Energy: in terms of installation efficiency
2. Environmental: in terms of atmospheric emissions
3. Economic: in terms of determination profitability
Continued…
6. • A thermal utilization installation was provided for incinerating plastic waste
• Incineration of plastic waste is highly beneficial because of its high LCV (lower
calorific value)
• Research conducted on an industrial scale in a plant that manufactures
Plastic tape
8. Construction and Testing Details
• Rotating kiln of a special and untypical structure
• Capacity value of wastes =36 MJ/kg
• Non-Flammable parts= Low
• Length-to-diameter ratio= 2:1
• Plant was tested with respect to:
permissible emissions to the atmosphere, thermal efficiency
11. Advantages and details of upgrade
• Design and construction of waste incineration system :
based on rotary kiln
• Heat recovery system: equipped with special oil-tube boiler
• Proximity of technological production lines and incinerator was reduced:
waste transport was reduced
• Time between creation & neutralization of waste: reduced
• Combustion process was simplified.
12. • Harmful emissions into the atmosphere: reduced
• On-site facility location: efficient use of the heat generated by waste
incineration process
• Local natural gas-fired boiler room: eliminated
• Export to external waste disposal facilities eliminated, large quantity
consumption of fuel for external transport reduced
Continued…
14. Thermal recycling technology :-
The investigated system of plastic waste incineration consists of the
following elements:
A. Loading system:-
In the recycling plant waste is crushed/shredded and compressed. In such
form, waste is then loaded in large containers with a capacity of 370 or
770 L.
After weighting the container is raised by the elevator above the loading
chamber and completely emptied.
When the loading chamber is full, horizontal hydraulic cylinder pushes
the waste into the rotary kiln. The average frequency of loading is every
15 min, with the average weight of a load of 50 kg.
15. B. Rotary kiln:-
built with a 2% incline sloping in the direction of the secondary combustion (afterburner)
chamber where incineration of plastic waste takes place
The duration of the incineration process depends on the LCV and the moisture content of
the waste.
Rotary Kiln is short but has large diameter.
C. Secondary combustion (afterburner) chamber :-
Where gases produced during the incineration process in the rotary kiln are afterburnt.
This process is conducted at temperatures from 1100 C to 1200 C, and the minimum
retention time of incinerated gases must not be less than 2 s.
17. D. Recovery boiler :-
After leaving the reactor, flue gas at temperatures from 1100 to 1200 C heat the
thermal oil to a temperature of approximately 280 C.
The flue gases flowing through the heat recovery system are cooled to
temperatures between 265 C and 280 C.
E. Flue gas cleaning system :-
Multi-sectional bag filter to remove dust. In addition, this system is equipped with
metering devices for dosing sorbent and urea.
19. Energy balance of the system :-
The energy flows through the incinerator with a heat recovery boiler is given by following
equation :
20. Energy efficiency coefficient :-
The energy efficiency of a system for the thermal recycling of plastic waste can be determined
using two methods:
a. Indirect method :- The indirect method involves determining all components responsible for
energy losses and is frequently performed via calculations (analytical method).
b. Direct method :- The direct method involves measuring the energy flux supplied to the system
and the heat flux transferred to the steam receivers (usable/effective heat).
> The coefficient of energy efficiency is defined as follows:
21. Description of the measurement system:-
The measurement system consists of three essential components
a) flux measurement of the following
b) temperature measurement using sensors with a measuring accuracy of 2.0%
c) continuous flue gas monitoring consisting of the following
▪ measuring component
▪ treatment and computing component
▪ auxiliary component
23. The concentrations of pollutants emitted into the atmosphere
were measured using the following methods:
• FT-IR measuring method
* based on the ability of polyatomic gas particles to absorb infrared radiation; the performed
quantitative analysis involved the measurement of CO, SO2, NO, HCl, HF and H2O,
• Measurement method based on a zirconia sensor,
* measuring the oxygen concentration in gases with a high content of combustible compounds and impurities
resulting from high temperature (for example, in the flue gases); the zirconia probe consisted of a heated
measuring cell, an electronic controller and a pneumatic unit supplying reference air.
24. • The parameters measured by the system for the continuous
monitoring of flue gas and their ranges and measurement errors are
shown in Table 3.
26. 1 . Test results for thermal waste recycling process
• Natural gas (additional fuel) was burned only during the start-up the system,
in order to reach a proper temperature in the rotating kiln and the afterburner
chamber
• During the testing period (steady state) only the waste was incinerated.
• The flue gas temperature at the beginning of the chamber (T1) fluctuated
within the range of 922 C and 1011 C, with an average value of 985 C.
• The temperature at the end of the rotary kiln (T2) was slightly higher and
fluctuated within the range of 993 C and 1048 C, with average of 1029 C.
27. • It is worth noting that very high temperatures occurred (T1) even in the front of the
rotary kiln, due to the:
1. High LCV of plastic waste.
2. It demonstrates rapid combustion practically from the time of loading
the waste into the rotary kiln.
• The combustion process was quite stable due to the specially selected length and
diameter ratios of the rotary combustion chamber.
• The flue gas temperature behind the secondary combustion (afterburner) chamber
(T3) fell within the range of 1030 C and 1384 C, below 1100 C were very rare.
*Initially, auxiliary burner turned on to maintain the minimum temperature above 1100 C; testing period, auxiliary
burner turned off.
29. • Actual concentrations of CO and volatile organic compounds, expressed as TOC
(total organic carbon), in the outgoing flue gas.
• Devices to sample the flue gas and to measure the mass flux of dust were
located on the exhaust chimney itself.
• The concentration of carbon monoxide in the flue gas ranged from 5 to 15
mg/m3, with an average value of 11.2 mg/m3.
30. • The concentration of TOC, fluctuated between 5 and 10 mg/m3, except for a few
peaks with values reaching up to 50 mg/m3. The average concentration of TOC in
the flue gases during the study period reached a value of 8.8 mg/m3
*The peaks occurred during the same shift. This observation shows that the experience of workers operating such systems also
affects the quality of combustion and emissions, especially when loading the waste.
31. • Flue gas temperatures when entering (T4) and leaving (T5) the thermal oil boiler
are very different.
• The mean temperature difference measured in the study period was 870.9 C.
• The exhaust gas temperature at the entrance varied in the range of 907.7.0 to
1263.3 C, with an average value of 1156.1 C.
• The flue gas temperature at the outlet, fluctuated in the range of 265.2 C and 336.7
C, with an average value of 285.2 C.
* The temperature of the flue gas leaving the oil boiler gradually increased with time of operation. At the beginning of
the test period, the heat exchange surfaces were clean. With the progressive pollution of the heating surfaces, the flue gas
temperature increased. At the end of the test period, it reached a value in excess of 300 C, the heat recovery boiler was then
cleaned. This situation occurred after the end of the study.
33. • The starting temperature of the oil (T7) varied in the range of 250.2 C to 290.4
C, with an average value of 272.4 C.
• The temperature of the heating oil returning from the processing equipment
(T6) fluctuated in the range of 211.1 C to 268.4 C, average value being 249.5 C.
• The installation of the heat recovery system resulted in the recovery of useful
energy in the form of hot thermal oil, average flux of which was Eue = 1269.6
kW, and the thermal efficiency of the entire system was ƞ = 65.2%.
35. • When burning this type of waste we achieved
: The reduction of greenhouse gas emissions
: In the analysed period, CO2 emissions were reduced by 298.7 kg/
h.
: Emissions of SO2, CO, NOx and dust were omitted.
: The effect of avoided emissions due to the elimination of transport
to external facilities processing plastic waste
38. • The primary objective of any business operation is its cost effectiveness.
• Analysis of the economic viability of any venture should demonstrate
whether the net financial result of implementing the investment will be
sufficiently high.
• basic input in the form of technical indicators . The capacity and
performance of the plastic waste incineration, the thermal power recovery
system and other technical parameters were determined based on the
conducted research.
40. basic input associated with economic aspects. In particular,
these aspects define the capital and operating expenditures of
the studied system.
41. • SPB (simple payback period) of the capital expenditures
incurred for its construction is 4.5 years.
• The IRR (internal rate of return) of the project was 16.1%,
which was higher than the expected 8.3%.
• NPV (net present value) of the project after taxes is greater
than zero. In the case presented, after 15 years
43. This paper presents the results of a pilot study of the installation of a
thermal treatment (incineration) facility for plastic waste. The study was
conducted in a plant that manufactures plastic tape (used for warning,
packing and masking purposes, and others) The system was considered
in terms of three aspects:
1- energy
2- environment
3- economic.
44. • In terms of energy, tests have shown the value of designing and building plastic waste
incineration (thermal disposal) plants with heat recovery. This type of plant, in addition
to performing its basic role (waste management), is also highly efficient in terms of heat
production.
• The process of intense burning of wastes has already taken place as temperature of
exhaust gases in the kiln reached in the testing period an average value of 985 degree C.
Though the rotating kiln was short, it was possible to use its volume to ensure the
maximum thermal performance. There was a stable and high temperature inside the
cubic volume of the kiln.
• The use of a heat recovery module resulted in useful energy that was recovered in the
form of thermal oil at a temperature of 280 C.
45. • The value of the energy flux averaged Eue = 1269.6 kW.
• Despite high temperatures of exhaust gases at outlet of the recovery oil boiler
resulting from the required parameters of heat oil, thermal efficiency of the whole
system (burning and heat recovery part) was satisfactory and relatively high n =
65.2%.
• Such good thermal efficiency was obtained owing to low losses of the heat flux
through the external wall of the rotating kiln (short and well insulated)to the
environment.
• At the same time, it was demonstrated that the assumed construction ratios of the
rotating kiln guaranteed a proper and suitable level of thermal processing of
wastes. At a sufficiently low rotary speed (2 rotations per hour), it was possible to
obtain the total content of organic coal in slag and ashes below 3.0%.
46. • Analysis of the environmental aspect proved that the actual emissions to the
atmosphere that resulted from the thermal treatment of plastic waste, in the
experimental system, during the study period were lower than the current
emission standards in force in the European Union.
• Due to the nature of the disposed waste, particular attention was paid to the
emission analysis of carbon oxide and volatile organic compounds.
• In both cases, the average daily emission limit values fell below the limits.
• The use of the heat recovery system also resulted in the reduction of greenhouse
gas emissions because the plant had its own boiler room fired with natural gas.
47. • In economic terms, it has been demonstrated that the test system is both cost-
effective and attractive from the economic perspective.
• The simple payback period (SPB) of capital expenditures for its implementation
was 4.5 years.
• The NPV (net present value) of the project after taxes was greater than zero.
• Obtaining such a good economic result was possible due to, among others, low
cost related to the construction of the room for the analysed technology.
• Owing to a small length of the rotating kiln, it was possible to reduce the room
in size by 35%.
49. 1. Thermal utilization (treatment) of plastic waste by Janusz Wojciech Bujak (Polish
Association of Sanitary Engineers, Division Bydgoszcz, Ruminskiego 6, 85-950
Bydgoszcz, Poland) from ENERGY JOURNAL, Elsevier Publisher.
2. As Mentioned in the paper itself.