All You Need To Know About The Process Of Converting Waste To Energy
Waste disposal is a major headache especially in industrialized nations.
Due to the production of lots of low-moisture content and the presence of very large volumes of municipal, industrial and hazardous waste, industrialized nations are forced to come up with dynamic waste treatment or management strategies. One such strategy, which has proved to be quite efficient, is called waste-to-energy (WtE) disposal. The term encompasses a number of waste treatment or disposal technologies all aimed at converting waste or garbage into a form of energy or into an energy producing compound. Depending on the technology used, the processed waste produces either heat, electricity, or any other energy-carrying compound like methane, hydrogen or carbon dioxide. WtE takes place in specially constructed plants that require a substantial amount of financial and manpower resources to setup and run. That is why expert energy financiers like America 2030 provide waste to energy financing to fund any prospective investor willing to try out such a venture. There is a huge deal of information about this effective waste handling solution and the following discussion attempts to highlight all the fundamentals.
There are several WtE techniques or technologies in application around the world today. All WtE methods can be split into two main classes, depending on the actual methodology or process used to convert the waste into energy and the kind of energy produced by the plant.
As the title implies, all the technologies featured in this category involve subjecting the waste to very high temperatures. They are further categorized according to the concentration of oxygen used. The first technology is incineration or direct combustion. The plant uses grate or uidized bed systems to burn the waste. The produced heat energy is used for a variety of uses including home heating, industrial heating, and steam heating for electricity generation with turbines. Modern plants are optimized to ensure very high performance levels of between 90-95% with no emissions.
The other type of thermal technology is called gasification, which treats the waste without combustion in low oxygen levels and moisture. Although there is no burning, the waste is still subjected to very high temperatures, which results in the production of synthesis gas or syngas. This gaseous energy product contains carbon dioxide, hydrogen, and carbon monoxide, which are all capable of burning to produce heat and electricity. There are four types of gasification methods including close-coupled, advanced, slagging, and plasma arc gasification. And last but least we have pyrolysis technology, which burns plastic and biomass without oxygen at very high temperatures. There are two types of pyrolysis technologies. Depolymerization also called hydrous pyrolysis uses moisture for garbage treatment in a thermo chemical decomposition process. There is also pyrolysis that uses only oxygen to decompose the waste into 3 compounds, namely syngas, bio-char and bio-oil.
In application, non-thermal methods are not viable WtE technologies because they can`t handle solid mixed municipal and commercial waste. The first technique is called anaerobic or bio-digestion. It is used to produce energy from moisture-rich biodegradable waste. Bacterial microorganisms decompose garbage to produce biogas in vacuums. The end products include methane and carbon dioxide — plus a stable residue called digestate.
Another biological technique is fermentation, which uses yeast to produce ethanol from sugar contained in organic waste.
Each of these WtE technologies have different benefits and problems but we will only look at general advantages and disadvantages of all of them due of space limitations.