[Gasification] Sweden's trash project / Japanese trash project

Mon Nov 12 13:38:02 CST 2012

At TK Energi we gasified sewage sludge in an entrained flow gasification process at a te,perature of approx. 16-1700 K.
The results of the modelling and the measurements for zinc in shown below. In order to verify the model we burned some sewage slude at 1500 K – see the results in the last box below. We gasified approx. 15.000 kg dry sewage sludge.
It was not easy to make accurate mass balances for all the inorganics components but we could verify the general tendency for zinc – almost no zinc in the bottom ash for gasification – for combustion up to 12-1400 K all the zinc in bottom ash.

The lines here below are the conclusions concerning zinc.

The model work predicted:
Zn has a curious behaviour:
It seems to be released in the gas phase at 1200 K in reducing atmosphere (gasification) whereas it is predicted to stay in the solid at the same temperature for combustion ! When the temperature increases, Zn is progressively released in the gas phase as metallic Zn (gasification, reducing atmosphere) or probably also as ZnO in combustion

Phases formées
1 bar

milieu oxydant
T 1200 K

milieu réducteur
T 1200 K

milieu oxydant
T 1500 K

milieu réducteur
T 1500 K

milieu oxydant
T 1800 K

milieu réducteur
T 1800 K

Cendres de combustion
(données TKE)

Zn

Soid phase
Zn (gas)
ZnCl2 (gas)
ZnO (gas)

98

2

0
100

71
27

0
100

0
99

1

0
100

60
gaz 40

Measurement shoved:
Zn stays mainly in the solid for combustion (as predicted) and is also partly released in the gas (55%) in gasification.
Pb, Hg, Cd, Ag, Zn are released in metallic form in the gas at high temperature in reducing atmosphere
Zn forms oxides (ZnO) in oxidizing atmosphere and is released at high temperature in the gas
Sometimes ZnCl2 is found at lower temperatures (below 1200 K) (steel corrosion problems)

Fra: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] På vegne af Tom Miles
Sendt: 12. november 2012 17:32
Til: 'Discussion of biomass pyrolysis and gasification'; mark at ludlow.com
Emne: Re: [Gasification] Sweden's trash project / Japanese trash project

Tom,

Where did the zinc from the tires end up in your process? In the ash?

In combustion it is oxidized to  fine particle and is usually removed from  the stack gas with an electrostatic precipitator.

Tom

From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of linvent at aol.com<mailto:linvent at aol.com>
Sent: Monday, November 12, 2012 8:28 AM
To: gasification at lists.bioenergylists.org<mailto:gasification at lists.bioenergylists.org>; mark at ludlow.com<mailto:mark at ludlow.com>
Subject: Re: [Gasification] Sweden's trash project / Japanese trash project

For dioxins need to be produced, the chlorine needs oxygen to form the intermediate chlorine dioxide and without the availability of oxygen, and the presence of excess hydrogen, dioxins are actually destroyed by the stripping of oxygen to form water with the hydrogen and the hydrogen produces hydrogen chloride or hydrochloric acid. There are a series of reactions and conditions needed to produce dioxins including temperature, residence time, oxygen, and designs of thermal systems can affect the production where a pyrolytic gas is combusted, they will be produced.

In our testing for the North Counties Association, a group of cities around San Diego, the ash and gas we produced from MSW/RDF operations in South Houston did not contain any dioxins. Additionally, with the interesting gas cleaning system we have developed, tires gasified contained no sulfur by FTIR analysis and other analysis. It was not a specific S removal system i.e., not designed specifically to remove S from the gas.
Sincerely,
Leland T. "Tom" Taylor
Thermogenics Inc.

-----Original Message-----
From: Tom Miles <tmiles at trmiles.com<mailto:tmiles at trmiles.com>>
To: mark <mark at ludlow.com<mailto:mark at ludlow.com>>; 'Discussion of biomass pyrolysis and gasification' <gasification at lists.bioenergylists.org<mailto:gasification at lists.bioenergylists.org>>
Sent: Sat, Nov 10, 2012 9:38 pm
Subject: Re: [Gasification] Sweden's trash project / Japanese trash project
Mark,

The Japanese unit looks like it might be a small rotary pyrolyzer that is heated by burning the offgas. In that case we would expect to see a char product and a clean stack.

Ebara is the main waste to energy company that uses gasification in Japan. Burn the gas directly into a close coupled boiler.

Japan funded extensive waste gasification in the 1990s. They tried several different types of gasifiers. Ebara is one of the few companies that still used gasification for waste. There are several companies that make rotary pyrolyzers. Last year in Kyoto we did not see evidence that they are used much for biochar production.  Most biochar seems to be made by very small scale stirred bed rice husk gasifiers by Kansai Corporation.. The gas is burned above the stirred bed and used to heat water for space heating or process heat. The biochar (called “kuntan”) sells for about $0.40/lb.

Tom

From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org<mailto:gasification-bounces at lists.bioenergylists.org?>] On Behalf Of Mark Ludlow
Sent: Saturday, November 10, 2012 7:01 PM
To: 'Discussion of biomass pyrolysis and gasification'
Subject: Re: [Gasification] Sweden's trash project / Japanese trash project

Tom,
The incinerators I’ve seen, operate with excess oxygen. This seems antithetical to gasification. Perhaps a two-stage gasifier?
Mark

From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of Tom Miles
Sent: Saturday, November 10, 2012 7:09 PM
To: 'Discussion of biomass pyrolysis and gasification'
Subject: Re: [Gasification] Sweden's trash project / Japanese trash project

You could call it a pyrolytic incinerator. The gases must be burned in conditions to completely destroy the dioxins. Even the poultry manure gasifier in West Virginia had to be tested for dioxins. Poultry litter manure has about 1% chlorine on a dry basis. Municipal waste also is loaded with salts from foods and fertilizers. We found much higher concentrations of salts in ash from MSW incineration than we expected.

Tom

From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of Lloyd Helferty
Sent: Saturday, November 10, 2012 4:49 PM
To: Discussion of biomass pyrolysis and gasification
Subject: Re: [Gasification] Sweden's trash project / Japanese trash project

In answer to Mark Ludlow's question, Where does the rest of the “trash” go?
That would probably be "up the stack" ~ i.e. == air emissions ??

In answer to John Miedema's question about "chlorides involved in the trash" and a possible dioxin problem?
Again, you might, depending on the TEMPS involved in the process.

  You might expect that one good way to avoid Dioxins is to avoid burning chlorinated plastics, i.e. PVC (Polyvinyl chloride), Chlorinated polyethylene (CPE), Chlorinated polyvinyl chloride (CPVC) etc.

  Yes, most dioxins arise in the condensed solid phase by the reaction of inorganic chlorides with graphitic structures in char-containing ash particles, with copper acting as a catalyst for these reactions, therefore the highest dioxin concentration is typically created by the pyrolysis of PVC.

   Large incinerators have mostly worked this out, however.  The Japanese [and German] tech is rather good at dealing with these things.

I don't know what kind of "air emissions" controls have been put on this particular system, if any.

 The single most important factor in forming dioxin-like compounds is the temperature of the combustion gases. Oxygen concentration also plays a major role on dioxin formation, but not the chlorine content.  Several studies have shown that removing PVC from waste would not significantly reduce the quantity of dioxins emitted.**

The design of modern incinerators minimize dioxins by optimizing the stability of the thermal process.  The EU emission limit is 0.1 ng I-TEQ/m3.  Modern incinerators not only operate in conditions that minimize dioxin formation, but are also equipped with pollution control devices which catch the low amounts produced.

** The European Union Commission published in July 2000 a Green Paper on the Environmental Issues of PVC noted that, "there does not seem to be a direct quantitative relationship between chlorine content and dioxin formation".
Similarly, another study commissioned by the European Commission on "Life Cycle Assessment of PVC and of principal competing materials" states that "Recent studies show that the presence of PVC has no significant effect on the amount of dioxins released through incineration of plastic waste."

Regards,

  Lloyd Helferty, Engineering Technologist

  Principal, Biochar Consulting (Canada)

  www.biochar-consulting.ca<http://www.biochar-consulting.ca>

  48 Suncrest Blvd, Thornhill, ON, Canada

  905-707-8754

  CELL: 647-886-8754

     Skype: lloyd.helferty

  Steering Committee coordinator

  Canadian Biochar Initiative (CBI)

  President, Co-founder & CBI Liaison, Biochar-Ontario

  National Office, Canadian Carbon Farming Initiative (CCFI)

  Partner of Toronto Urban Ag Summit www.urbanagsummit.org<http://www.urbanagsummit.org>

  Manager, Biochar Offsets Group:

           http://www.linkedin.com/groups?home=&gid=2446475

   Advisory Committee Member, IBI

  http://www.linkedin.com/groups?gid=1404717

  http://www.facebook.com/group.php?gid=42237506675

  http://groups.google.com/group/biochar-ontario

  http://www.meetup.com/biocharontario/

  http://www.biocharontario.ca

   www.biochar.ca<http://www.biochar.ca>

"It is the path, more than the arrival at the destination, that is important"

 - Gandhi
On 2012-11-10 12:36 PM, John Miedema wrote:
I am curious about the chlorides involved in the trash (plastics)? Would not there be a dioxin problem?

John Miedema
BioLogical Carbon, LLC

________________________________
From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of Mark Ludlow
Sent: Saturday, November 10, 2012 2:24 AM
To: 'Discussion of biomass pyrolysis and gasification'
Subject: Re: [Gasification] Sweden's trash project / Japanese trash project

Where does the rest of the “trash” go? Just, “Somewhere”? RE: Conservation of Mass.

Mark

From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of Terry & Susan Layman
Sent: Friday, November 09, 2012 4:08 PM
To: Gasification at bioenergylists.org<mailto:Gasification at bioenergylists.org>
Subject: Re: [Gasification] Sweden's trash project / Japanese trash project

The Swedish are probably using the same system the Japanese invented.

Leave it to the Japanese to perfect a system, that virtually elimanates
trash. Each day Iwamoto's "Super Stone Clean Waste Treatment'' <http://superstoneclean.com/waste-treatment-solutions/> processors
can take a 20 ton pile of common garbage, and reduce it to less than 8 gallons
of what they call biochar.

Just watch their video. then you can see first hand the machine and the process.
I, wouldn't classify it as BioChar, but it looks to me like ashes.

Reduces waste volume from 1/100th to 1/3000th of original input:
1,000kg waste →300g ashes ( 2,200 lbs waste to 10.58 oz's ashes )

This is probably the most advanced system for Gasification.

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