solid waste management hydrothermal treatment using subcritical water

8/10/2019 Solid Waste Management Hydrothermal Treatment using Subcritical Water

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Solid Waste

Management

Presented By:-

Vijendra Kumar Gupta

Urvashi Tiwari

Prateek Aniruddha Sarin

Kuldeep Singh Bhati


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Overview

Introduction

Hydrothermal Treatment by usingSubcritical water

Case study

Comparative study

References


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Municipal Solid WasteMunicipal solid waste(MSW), commonly knownas trashor garbage(US), refuseor rubbish(UK)is a waste type consisting of everyday items thatare discarded by the public.


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Disposal of MSW

Different management/treatment which aregiven to the waste:-

1. Land Filling


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Incineration &Gasification


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Hydrothermal Treatment UsingSub-critical Water (HTSW)

Hydrothermal treatment technology employs thecombination of heat and water to convert

unutilized resources into uniform product.

Pressurised hot water is known as subcriticalwater.


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Why subcritical water?

It has hydrolytic and pyrolitic reactioncharacteristics, result from a decrease in thedielectric constant and increase in the ion product

of water at temperatures and pressures below

and near 374oC and 22.1 Mpa.


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Features of HTSW

No drying process is required prior to HTSW.

Char is produced with minimal carbon loss.

The char produced has a heating value

comparable to that of lignite & brown coal.Liquid filtrate produced has organic compoundssuch as Alcohols, ester, aldehydes etc. which canbe recovered as valuable products.


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Process Description

This process operates as a batch system.

Municipal Solid Waste (MSW) and distilled water(three times of MSW by mass) are added to anautoclave reactor.

The system is then stirred at 150 rpm.

Steam is now added at T=75-150oC

Now reactor is set at one of the following

conditions-Low Temperature conditions (234oC, 3 MPa)

High Temperature conditions (295oC, 8 MPa)


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These conditions are maintained for 5 min in thereactor.

Nitrogen gas (T=75oC ) is then purged into theautoclave reactor in order to discharge theresulting gas.

The resulting mixture (constituting solid, liquidand gas phase) is cooled down in a vapor gascondensing bottles, and non condensable gas

then being collected in Tedlar bag.


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Setup

In-Hee Hwang, Hiroya Aoyama, Toshihiko Matsuto, Tatsuhiro Nakagishi, Takayuki Matsuo.Recovery of solid fuel from municipal solid waste by hydrothermal treatment using subcriticalwater. Waste Management 32(2012) 410-416.


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The solid-liquid mixture is collected by rinsingwith distilled water and then filtered with 1micron pore-sized filter paper.

Solid components are then dried for 105oC for 12h, which are then pulverized to grain-sized 500micron particles.

The filtrate obtained is then cooled and scrubbedfiltered with 1 micron pore-sized filter paper.


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Case Study of AurobindoHostel

1. It accommodates 32 dustbins each producing 5Kg of solid waste daily.

2. Besides this solid waste of mess & canteenconstitute 200 kg on daily basis.


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Composition of SW

30%

40%

20%

10%

Organic Food WastePlastics/Polythene

Paper waste

Sand & others


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Yield at Lower Temperature

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Paper Food Wood Plastic

Yield 0.66 0.66 0.59 0.98

Yield

Lower Temperature


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Yield at High Temperature

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Paper Food Wood Plastic

Yield 0.66 0.66 0.59 0.98

Yield

High Temperature


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Heating Value Produced

Type ofWaste

Amountofwaste(in kg)

HeatingValue inLT (inKJ/kg)

EnergyProducedin LT(in KJ)

HeatingValue inHT (inKJ/kg)

EnergyProducedin HT (inKJ)

Paper 32 13780 260166.40 21359 307569.60

Food 248 24106 3766321.44 24727 3372762.80

Wood 0 21571 0 25724 0

Plastics 64 0 0 0 0

Total 354 4026487.84 3680332.40


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Heating Value of LPG= 49742 KJ /kg.

So the energy produced by the char producedfrom solid waste collected from Aurobindo Hostelis equivalent to 74 to 81 kg of LPG which is equalto 5 LPG domestic cylinder(14.2kg).


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Comparative StudyParameter Land

fillingIncineration

Gasification HTSW

Installation &OperationalCost

Low High Very High High

EnvironmentalImpact

Affectsland,water andair in localareas.

Affects airand largelyresponsiblefor climatechange.

Pollutes airand adds toglobalwarming.

Low impact.

Service inReturn

Nothing Less energyis recoveredin form of

heat.

High amountof energy isproduced.

Very highamount ofenergy is

produced.Ease ofoperation

Cant be

donelocally.

Cant be

done locally.Cant be

done locallyand specialskills arerequired.

Can be donelocally withless amountof specialskills

required.


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References

In-Hee Hwang, Hiroya Aoyama, Toshihiko Matsuto, TatsuhiroNakagishi, Takayuki Matsuo. Recovery of solid fuel from municipalsolid waste by hydrothermal treatment using subcritical water.

Waste Management 32(2012) 410-416.Brunner, G., 2009. Near critical and supercritical water. Part I.

Hydrolytic and hydrothermal processes. The Journal ofSupercritical Fluids 47, 373381

Thermochemical Liquidization and Anaerobic Treatment of KichenGarbage. Journal of Fermentation and Bioengineering 83 (5),451455. Shen, D.K., Gu, S., 2009.

solid waste management hydrothermal treatment using subcritical water

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