Waste to Carbon Char to Electricity

Yes imagine that. Electricity from waste. In Quezon City, we are already extracting methane from our controlled disposal facility. This methane is currently being used to run a 250kw generator, enough to power the facility, its perimeter lighting, and a free public clothes-ironing facility. The next phase of the project is to install a 1 MW capacity generator and sell surplus electricity to the main power grid.

But this proposal which we received from Nasmech Technology Sdn Bhd of Malaysia is quite different. I'm not sure if I'm allowed to share this information with you, but I guess it would be the benefit of all if more people around the world learn about this technology. It is not groundbreaking in anyway. We have previously received other proposals invovling other technologies such as pyrolysis, which can derive fuel from waste or KDV (german for catalytic depolymerization process, not exactly sure of the company but will blog about it some other time) which can derive diesel from waste and a local company which produces "green charcoal" from waste.

The difference is that Nasmech uses Carbonization technology which converts all organic

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waste into carbon char which can be used to run a power plant in a similar way that coal-fired power plants are operated. The difference is that carbon char is a cleaner fuel that will not produce dioxins and other toxins (that is the claim). How is that possible?

Let's begin by discussing the carbonization process. I am not an engineer so I'll explain this in layman terms, the way I understood it. First of all, organic materials are composed of 4 basic elements: C-H-O-N. That is Carbon, Hydrogen, Oxygan and Nitrogen. Polycarbons or plastics are also organic (they are derived from petroleum) but have extra elements of Sulfur and Chlorine.

As Joey (sorry, I forgot the full name of the president - or was he the COO? will update once I get my facts correct, hehe.) puts it, the process is like roasting. Waste is placed inside a slow-rotating drum.Waste need not be sorted except of course for the bulky ones which can be easily separated like construction debris. Other inorganic waste like metals and glass would remain unchanged after the carbonization process so it will be easier to sort them out later.The drum is placed in a chamber where dry heat is pumped. Heat reaches at about 600 degrees celsius but heating is done incrementally, in stages.

First is the drying stage where moisture is evaporated. Then the pre-carbonization stage, where heat is increased to remove sulphur. Then, the carbonization stage, where heat is at its peak and waste is broken down into basic carbon. Joey explains that each type of material has its sort of "carbonization point", like a melting point, but instead of melting, the H-O-N bonds are destroyed leaving only Carbon. The "carbonization point" varies per type of material that is why heating is increased incrementally. After that is the cooling stage where the temperature is taken down slowly so as not to introduce oxygen that might cause the char to burn and instead leave ashes.

Carbonization is not burning or incinerating because the process is done without the presence of oxygen (<1%). Because of the heating, most harmful compounds are eliminated. There is also an air pollution control chamber where all emissions are directed and properly treated. A scrubber is introduced at the end of the air pollution control process flow thereby keeping the levels of dioxin, furan, NOx, SOx, CO, dust particles and even odour way below the regulartory standards. Verified results of emission tests are also attached in the presentation.

That's the technology, which they say was started in Japan but perfected or at least improved by Nasmech. They actually have 4 pending patents for the technology.

Sustainability

I'm pretty stoked that they have not seriously considered using the resulting char as their main source of fuel. If you're talking about "cradle-to-cradle" as oppose to "cradle-to-grave" then you must ensure that you are operating in a closed-loop system wherein you operate independently from external fuel sources. They say that the technology may be powered by LPG, bunker fuel or other types of fuel and that the resulting carbon char is of high-quality and I'm assuming that they're telling us that its actually more expensive to use the carbon char because it can be sold at a higher price than what they will pay for the other types of fuel. Is it really that more expensive? Remember, we are recovering it from waste. And besides, if you yourself do not use it, how else could we expect other people to buy it?

They should learn from MAPECON Green Charcoal Philippines, Inc. (will blog about them some other time). The concept of their end product is the same. They produce "green charcoal" which may be used as fuel. (I hope I could discuss their process; they use an enzyme additive which transforms shredded biodegradable matter into "green charcoal".) They are still studying the feasibility of using "green charcoal" to fuel power plants but are already using their products for their own consumption. They are a leading exporter of activated carbon to Africa. Thanks to their "green charcoal" which now replaced the more expensive bunker fuel in their plant. Anyway, more about them in a separate blog soon.

The plan is for Nasmech to also set up a power plant that will use the carbon char. I just hope that will all the incentives from the Clean Development Mechanism and the Philippine Renewable Energy Act, the undertaking will prove to be a financially viable one. They are now studying the ROI and looking for potential investors to partner with us.

Projections

So far the only projections they gave us is that a 200 ton capacity system (that's daily processing capacity) may generate 40 tons of carbon char daily (that's 20% recovery). The char would have 6000 kcal/kg energy potential and the power plant would have 2.3 MW capacity (would have to verify my data, I'm just writing on top of my head) and the investment (excluding civil works) would stand at about $ 23 M (US) for the 200 ton plant and would require land area of 3 hectares.

Closing

They are hoping that they could come up with an ROI of less than 7 years to attract investors. Me? I hope that given a proper cost-benefit analysis which considers its environmental benefits and multipliers, we could convince the City Mayor to share with the cost of investment.

And also, I hope that we could make those who would oppose the project, saying that it would discourage people from segregating their waste, to understand that the project still adheres to the principle of waste recovery. And let's be realistic, it's almost been 10 years since the Philippine Ecological Solid Waste Management Act was passed and yet until now compliance to waste segregation is disappointingly low. Yes, the technology offers a quick-fix solution, but I think what is important is that it works, its easier to implement and that it still promotes waste recovery.