http://gasification.org/page_1.asp?a=87&b=85

Gasification Facts Gasification vs. Incineration

How is Gasification Different from Incineration?

Increasingly, gasification is being used to convert municipal solid waste, or MSW, into valuable forms of energy. While this type of waste has been burned, or incinerated, for decades to create heat and electricity, the gasification process represents significant advances over incineration. In order to understand the advantages of gasification when compared to incineration, it’s important to understand the significant differences between the two processes:

Incineration literally means to render to ash. Incineration uses MSW as a fuel, burning it with high volumes of air to form carbon dioxide and heat. In a waste-to-energy plant that uses incineration, these hot gases are used to make steam, which is then used to generate electricity.

Gasification converts MSW to a usable synthesis gas, or syngas. It is the production of this syngas which makes gasification so different from incineration. In the gasification process, the MSW is not a fuel, but a feedstock for a high temperature chemical conversion process. In the gasifier, the MSW reacts with little or no oxygen, breaking down the feedstock into simple molecules and converting them into syngas. Instead of making just heat and electricity, as is done in a waste-to-energy plant using incineration, the syngas produced by gasification can be turned into higher valuable commercial products such as transportation fuels, chemicals, and fertilizers.

In addition, one of the concerns with incineration of MSW is the formation and reformation of toxic dioxins and furans, especially from PVC-containing plastics and other materials that form dioxins and furans when they burn. These toxins end up in exhaust steams by three pathways:

•By decomposition, as smaller parts of larger molecules,

•By “re-forming” when smaller molecules combine together; and/or

•By simply passing through the incinerator without change.

Incineration does not allow control of these processes, and all clean-up occurs after combustion.

Gasification is significantly different and cleaner than incineration:

•In the high temperature environment in gasification, larger molecules such as plastics are completely broken down into the components of syngas, which can be cleaned and processed before any further use,

•Dioxins and furans need sufficient oxygen to form or re-form, and the oxygen-deficient atmosphere in a gasifier does not provide the environment needed for dioxins and furans to form or reform,

•Dioxins need fine metal particulates in the exhaust to reform; syngas from gasification is typically cleaned of particulates before being used,

•In gasification facilities that use the syngas to produce downstream products like fuels, chemicals and fertilizers, the syngas is quickly quenched, so that there is not sufficient residence time in the temperature range where dioxins or furans could re-form; and

•When the syngas is primarily used as a fuel for making heat, it can be cleaned as necessary before combustion; this cannot occur in incineration.

The ash produced from gasification is different from what is produced from an incinerator. While incinerator ash is considered safe for use as alternative daily cover on landfills, there are concerns with its use in commercial products.   In high-temperature gasification, the ash actually flows from the gasifier in a molten form, where it is quench-cooled, forming a glassy, non-leachable slag that can be used for making cement, roofing shingles, or used as an asphalt filler or for sandblasting. Some gasifiers are designed to recover melted metals in a separate stream, taking advantage of the ability of gasification technology to enhance recycling.

http://www.waste-management-world.com/articles/2013/02/jv-brings-waste-to-energy-gasification-technology-to-poland.html

Energy Canada (WtEC) has formed a joint venture with Polish investment and property development company, Rank Progress to develop projects in Poland and Croatia.

The joint venture – Rank Recycling Energy (RRE) – will seek to work in partnership with municipalities to provide waste processing facilities through a Design, Build, Own and Operate business model.

The JV Agreement was signed in the Canadian Embassy in Warsaw by Jan Mroczka, president of Rank Progress and Rod Taylor, CEO of WtEC in the presence of Alexandra Bugailiskis, the Canadian ambassador designate to the Republic of Poland.

http://www.energyglobal.com/news/special-reports/articles/The_economic_benefis_of_gasification_005.aspx

One of the most compelling challenges of the 21^st Century is finding a way to meet national and global energy needs. Oil refineries can help meet this challenge while generating more economic value by adopting a gasification process.

The economic benefits Of gasification

Refineries usually convert their waste or residue into asphalt or bitumen, products from which they derive very little economic value. Gasification technology converts this waste into valuable commodities, such as power, steam, oxygen, hydrogen and nitrogen, that are used in everyday refinery operations. A study by the National Energy Technology Laboratory (NETL) estimates these savings are worth US$ 13000 – $ 55000/day. Additionally, a refinery gasification plant is an attractive alternative energy source in regions with high natural gas prices.

In addition to the above operating expense savings, refineries can reduce their capital budgets when installing a gasification plant. Used plants are sold at a fraction of the cost of a new plant, often yielding savings of 40 – 50%. With new gasification plant investments running at US$ 500 – 800 million, the savings can fund a significant number of incremental capital projects. In addition to saving their investment capital, used plants save companies time and human capital. Generally speaking, facilities such as a gasification plant can be dismantled, relocated, re-assembled and operating in less than half the time of designing and building a new plant from scratch.

For example, International Process Plants (IPP) has a gasification plant available which converts refinery residue waste into clean synthetic gas. This plant consumes 1400 tpd of heavy residues to produce over 3000 tpd of clean syngas and can be modified to use petcoke or coal.

Refinery gasification opportunity

The IPP plant uses licensed technology from Texaco (GE Gasification), ABB, UOP, Parson and Praxair. The facility is over-designed to accommodate crude oils other than the standard Arab Heavy, such as Basrah Medium high-sulfur and Iranian Heavy feedstocks.

Units of operation

The Texaco gasification system is the core unit in this plant. It uses quench gasifier technology because:

• It is the best choice for gasifying feedstocks, such as refinery residues that have a high concentration of metal.
• It has a proven success record in the refinery industry.
• It is reliable and simple to operate.
• It offers superior environmental benefits.

Other units of operation include:

• Carbon extraction unit.
• Gas cooling and hydrolysis section designed by ABB Lummus Global.
• UOP acid gas removal system.
• Sulfur recovery unit comprised of two Parsons Claus units.
• Praxair™ air separation unit (ASU) produces oxygen that is 95% pure.
• Grey water treatment unit.
• Sour water stripper unit.

Written by International Process Plants.

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