Myth #1: Gasification is an Unproven Technology
Truth: Gasification is a technological process that can convert any carbonaceous (carbon-based) raw material such as coal into fuel gas, also known as synthesis gas. Gasification has been around for over 180 years with 60 years in refining, fertilizing, and chemical industries and over 35 years in the electric power industry.
The Ways2H process has been engineered, refined, and enhanced over 16 years. With four generations of demonstration units and over 6000 hours of operation, our systems are now available for commercial use.
Myth #2: Gasification Systems are Too Limited in Size and Scale
Truth: Gasification of biomass and municipal solid waste does not require larger gasifiers that are used in industrial applications. Newer technologies have gone far beyond the smaller “hobby-sized” units.
Ways2H systems are scalable from a 50 ton per day stationary system down to a 1 ton per day transportable system. Our feedstocks include organic waste streams including plastics, municipal solid waste, sludge, and medical waste.
Myth #3: Gasification Systems are Unsafe
Truth: Gasification is a partial oxidation process. The term partial oxidation is a relative term which simply means that less oxygen is used in gasification than would be required for combustion (i.e., burning or complete oxidation) of the same amount of fuel. In conventional gasification systems, this partial oxidation of the feedstock is the source of energy for gasification.
Our systems are different. They use char, the byproduct of the gasification process, as the energy source. As a result they are even cleaner than conventional gasifiers as char is basically pure carbon and it burns at very high temperature. Another result of this feature is self-balancing. Our process is designed so that it naturally prevents over-heating or tar generation, leaving the optimum amount of fuel for heat production.
Myth #4: Gasification Systems are a Financial Risk
Truth: Gasification can help the world two-fold. It can manage its waste while producing the energy and products needed to fuel economic growth. Gasification offers an alternative to more established ways of converting feedstocks like coal, biomass, and some waste streams into electricity and other useful products.
Ways2H systems create value out of waste. Our system is used to produce hydrogen, which can be used as transportation fuel as well as for heat and electricity to buildings.
Gasification Misconceptions and How Ways2H Systems Differ from Conventional Gasification
“Gasification is an old technique so what is the use of reviving it?”
Gasification, indeed, is not new. In the early 20th century, “town gas” was actually made out of coal via gasification until it was replaced by Natural Gas. Germany became the main expert of Gasification during WW-II as it was an important method of making fuel for their war effort. In the US, gasification technology was also used to produce gas from coal. Reviving gasification using modern techniques such as those used by Ways2H systems, can help the environment reap the benefits that conventional gasification offers without the harmful greenhouse gas emissions.
“Gasification does not work, there has been monumental failure stories with this technology”
Gasification works perfectly, and has significant success track record (see question above) with consistent, homogenous feedstock such as coal or wood chips. However, it is true that when applied various feedstocks mix, the variation in feedstock quality can significantly impact the process temperature, which is key to its stability. This is why some projects have indeed met several operational challenges: process temperature was not stable, and led to inconsisten performances, or even process interruption. Too low temperatures cause the production of tar, which may clog the systems, too high temperatures may cause pressure bursts and damage the reaction vessels.
“How is the gasification of waste material different?”
We use a thermo-chemical process which, by design, is more efficient and stable than traditional gasification technology. This process does not incinerate the feedstock or a fraction of it, as does conventional gasification. Therefore, it can create a much cleaner end-product (hydrogen) without the hazardous emission resulting from raw feedstock incineration.
Handling heterogeneous feedstock, such as biomass and municipal solid waste (MSW), for thermal conversion is difficult due to the unpredictability of the fuel. The heating value and composition of the feedstock will vary continuously with the incoming flow of fuel.
Our systems are self-stabilizing whereas conventional gasification systems are designed to operate within a specific temperature interval to obtain the right condition for gasification reactions. As a result, commercial systems require continuous monitoring during operation to sustain the target temperature.
“What is the difference between the technology of the Ways2H system and conventional Gasification?”
First, Ways2H is not gasification. Our “vapolyisis” technique is a two-stage process, where a chemically organic (meaning that it contains carbon and hydrogen: biomass is organic, but so are plastics or hydrocarbon-derived materials) feedstock is converted to a hydrogen-rich syngas. In the first stage, the feedstock is heated indirectly by solid heat carriers under a constant flow of steam/vapor. The energy source for the heat carrier is the inherent carbon content in the feedstock. In the second stage, the gas mix resulting from stage 1 is further processed in the presence of steam, to maximize its hydrogen contents.
Accordingly, there is no incineration or combustion of the feedstock as there is in conventional gasification. It is essentially a cracking process where the organic waste material is cracked into its gaseous components, rather like the refinery process that cracks hydrocarbons into their components. This process occurs in an inert atmosphere, hence there is no combustion of the feedstock, nor are there associated impurities.
Second, our systems are self-sustainable. A dual bed design where the heat required by gasification is transferred using a ceramic heat carrier that is easily separated from the residual char and transported by gravity and mechanical means. During the steady state of operation, the char and reject gas from a hydrogen PSA are sufficient to control the heat carrier preheater temperature.
Third, the gaseous components from the pyrolysis reactor pass to the reformer with a minimal amount of oxygen which reacts with the combustible gas to increase the temperature, to a level where certain gaseous components react to create the maximum amount of high value hydrogen.
Fourth, the heat required in the convection cracker is supplied by heat carriers, such as ceramic beads, rather than combustion. As these heat carriers pass through the convection cracker, they pick up the char which is practically pure carbon. At the exit of the convection cracker the heat carriers are separated from the char.
Fifth, the char is then burned at very high temperature, more than 1000 degrees centigrade, in a combustor. The flue gases from the combustor then heat the recirculated nonreactive heat carriers. These heat carriers are then circulated back through the convection cracker to supply the cracking energy, breaking all the solid organic matter molecules into their near-elemental components: hydrogen, carbon monoxide, solid carbon, carbon dioxide, steam, etc. This use of these heat carriers versus combustion in the pyrolysis reactor is a major differentiator in maximizing the hydrogen recovery and minimizing impurities. It also allows for a variety of feeds: wood, agricultural waste, plastic, municipal solid waste and a mix thereof.
Sixth, the gases from the reformer are then purified and the high value hydrogen is separated from the remaining gases which are cross exchanged to gain process heat.
“Why is only the char burned in the combustor?”
Pure carbon burns at a higher temperature and is cleaner, thus causes less emissions. No dioxins, no furans. Furthermore, the flue gas resulting from the combustion of this carbon flows through a separate stream and does not come into contact with the product gas from the feedstock.
If ash or char agglomeration occurs, the mechanical heat carrier/char separator and the mechanical movement of ash out of the combustor provides a direct outlet for clinkers.
“Why wasn’t combustion or incineration used like in conventional gasification?”
The Ways2H system is self-sustainable and does not require an external source of energy. It is a continuous, automated process that use ceramic beads as heat carriers to move heat from the combustor to the convection cracker. Flue gas from the combustor is passed through the preheater where the ceramic heat carriers are heated and staged to drop down through the convection cracker. This flue gas is controlled so that the heat carriers are heated to a constant temperature, usually 800ºC. The convection cracker resembles an updraft gasifier in the sense that the feedstock proceeds though a drying zone and a final char gasification zone as it flows down the vessel. This method allows for a continuous process without the need for combustion or incineration of the feedstock.
Because there is absolutely no combustion of the feedstock, there is no production of complex hazardous compounds. Also, the energy value in the initial feedstock is better preserved and can be more efficiently recovered in the gas. In addition to that, our process also includes a second phase where hydrogen content is pushed to its maximum, between 50 and 55% of the total product gas volume. All the carbon-containing molecules - which happen to have minimal hydrogen contents since methane has been converted into H2 and CO - are recycled back into the system as energy source. Most of the hydrogen contained in the feedstock is recovered as the final product gas. Depending on the final use of that hydrogen, different separation techniques can be used to provide various purity levels, from rough 95% to the 99.999% required by PEM fuel cells.
“In what sizes and to what capacities can the system be built?”
Systems are available from 1 ton/day waste processing capacity in our transportable units and between 8-50 ton/day in our stationary units. These systems are tailored and sized for decentralized deployment. Hydrogen logistics is a challenge, and so is transportation of garbage. These systems are ideally installed where waste is being produced, and where hydrogen will be consumed.
“Eliminating waste and destroying hazardous elements is the good upstream side of the system. What can it produce on the downstream end?”
Liquid fuels contain carbon and their use therefore generates CO2 that is inevitably sent back to the atmosphere, short of being able to recover that CO2 from every tailpipe. Our solution, by providing separation of hydrogen and carbon at source, offers the potential for true carbon negativity. The process continues 24/7, in contrast to solar and wind which are intermediate sources. Produced hydrogen can be used directly for generating electrical energy in a genset or used for fuel cells, either stationary or on-board vehicles, from bicycles to heavy-duty trucks, trains or even boats. The only byproduct from hydrogen used as a fuel is water, so pure that it is even possible to drink it. CO2 can be used in greenhouses for agriculture, sequestered underground in oil formations or saline aquifers, or upcycled to produce construction materials. In any case, with such processing it will be ultimately removed from the atmosphere. The low-grade heat can be used for cooling/heating in Heat pumps. By this the circle is closed on the low part of the circle. Waste has become a thing of value.
“What is the quality of the produced hydrogen?”
The outlet syngas in our systems is very high quality with relatively low residual hydrocarbon content. The syngas typically has a hydrogen content of 50-53vol%. Then this syngas is sent to a hydrogen separator, typically a device known as a PSA (Pressure Swing Absorber). PSAs can deliver hydrogen to 99.999% purity, the very high degree of purity required by Proton Exchange Membrane Fuel Cells.
“Are there any control issues?”
In conventional gasification, if the feedstock is rather clean and predictable (like pure wood or coal), the process will be fairly easy to control, and predictably clean. Using too much of the feedstock as the heat source, gasification temperatures are usually rather low. This causes incomplete gasification. It then produces intermediate compounds and tar. Low temperature combustion also causes dioxins, furans, as well as other compounds that would not happen at higher temperatures. Using MSW adds up further potential issues due to the inconsistency (moisture, heating value) of the fuel, which has a direct impact on the process stability.
The Ways2H advanced gasification process is an indirect gasification system that allows for easy control of gasification reactions and is furthermore inherently a self-balancing system as it has sufficient char and reject gas from a hydrogen PSA to sufficiently control the heat carrier temperature.