**2. Market interest in gasification and pyrolysis**

Gasification is a partial oxidation processes in which the majority of the carbon is converted into the gaseous form-called syngas-by partial combustion of a portion of fuel in the reactor with air, pure oxygen, oxygen-enriched air or by reaction with steam. Relatively high temperatures are employed: 900- 1100oC with air and 1000-1400oC with oxygen. Gasification as a technology underwent major development during the oil price crises of the 1970s and 1980s.

Pyrolysis is the thermal degradation of carbonaceous materials. It occurs at lower temperature than gasification (typically 400-800oC), either in the complete absence of oxygen, or with such a limited supply that gasification. Pyrolysis has been promoted for biomass applications and in the treatment of scrap tyres, bur rarely as a stand-alone application for MSW.

Energy recovery is a secondary goal of waste incineration: thermal waste treatment and energy recovery are "married" within the waste-to energy plant (Pfeiffer, 2004). From an economic point of view, a waste–to- energy plant treating MSW is an enterprise using a special fuel.

The main potential benefits and advantages of pyrolysis and gasification of waste with respect to incineration are (Juniper, 2001; Klein et al., 2002; Malkow, 2004 as cited in Astrup

 The possibility and flexibility to recover chemical energy in the waste as hydrogen and/or other chemicals feedstocks rather than converting this energy into flue gases.

Gasifications units operating with a low fuel load, potentially facilitating small plants

Relatively homogeneous fuels are needed. Either specific material fractions can be fed

 Although theoretically possible, the pyrolysis and gasification processes are complicated to control and troubles with slagging, tar production, and contaminants in

 Numerous waste related pyrolysis and gasification technologies exist, many of these only demonstrated in small scale and/or applicable to specific fuel types.. This requires careful review of the appropriateness of a specific technology for a particular waste mix,

Overall energy conversion efficiencies of existing installations have been unable to

Gasification is a partial oxidation processes in which the majority of the carbon is converted into the gaseous form-called syngas-by partial combustion of a portion of fuel in the reactor with air, pure oxygen, oxygen-enriched air or by reaction with steam. Relatively high temperatures are employed: 900- 1100oC with air and 1000-1400oC with oxygen. Gasification as a technology underwent major development during the oil price crises of the 1970s and

Pyrolysis is the thermal degradation of carbonaceous materials. It occurs at lower temperature than gasification (typically 400-800oC), either in the complete absence of oxygen, or with such a limited supply that gasification. Pyrolysis has been promoted for biomass applications and in the treatment of scrap tyres, bur rarely as a stand-alone

Energy recovery is a secondary goal of waste incineration: thermal waste treatment and energy recovery are "married" within the waste-to energy plant (Pfeiffer, 2004). From an economic point of view, a waste–to- energy plant treating MSW is an enterprise using a

Improved quality of solid residues, particular for high-temperature processes.

The main drawback of the current technology for pyrolysis and gasification are:

to the gasifier, or mixed waste can be pretreated and homogenized.

& Bilitewski, 2010):

Potentially beter overall energy efficiency.

 Potentially better option for CO2 capture. Potentially lower emissions of dioxins.

the produced gas are not uncommon.

compare with modern waste incinerators.

**2. Market interest in gasification and pyrolysis** 

Less trouble with corrosion.

producing less than 1 MW.

Potentially lower costs.

local conditions, etc.

1980s.

application for MSW.

special fuel.

Some technologies, including gasification and pyrolysis, offers flexibility in terms of energy production and material recycling, and is an attractive technology option for Integrated Waste Management.

The main advantage that gasification has over incineration is its ability to conserve the chemical energy of waste in the produced syngas rather than convert it to heat energy in hot flue gas. Another reason for interest in gasification is the view by political decision-makers (especially in the UK) that gasification is an alternative to incineration, because which would mean that incineration would no longer be necessary.

The United States Department of Energy (DOE) sponsored the 2004 World Gasification Survey in order to accurately describe the world gasification industry as it exists today, to identify planned capacity additions, and to keep the gasification community apprised of current data and trends (National Energy Technology Laboratory [NETL], (2005).

An additional 38 plants with 66 gasifiers have been announced and are forecast to become operational between 2005 and 2010, according to the 2004 survey. The additional capacity from these new plants is 25,282 MWth, an expected increase of 56%. Worldwide capacity by 2010 is projected at 70,283 MWth of syngas output from 155 plants and 451 gasifiers.

 Regional distribution: The Africa/Middle East region will lead the world's regional growth with 43% of planned capacity growth from 2005 to 2010, all from a single gas-toliquids (GTL) project in Qatar that will produce liquid fuels from natural gas. The Asia/Australia region has planned projects that comprise 37% of the total planned growth, with China leading in this region. By contrast, plans for new gasification plants slowed in North America due to factors such as the economy and natural gas prices.

Feedstock distribution: Coal is the feedstock of choice for new gasification projects, identified for 29 of the 38 new plants (largely on the strength of the 24 chemical plants to be built in China). However, natural gas will be used in the largest single project from 2005 to 2010 at the nearly 11,000 MWth gas-to-liquid.
