Gasifier and Incinerator for Biomass Sludge Destruction

Abstract

A device for gasifying biomass sludge having particle size less than 1 cm, and 20% to 100% solids content has a primary chamber, a fume transfer vent, a mixing chamber which accepts fumes from the primary chamber, and an afterburner chamber in fluid communication with the mixing chamber. A secondary burner produces an initial heating flame within a vertical portion of the afterburner chamber. A heat transfer chamber is in fluid communication with the afterburner chamber. Heated gases from the afterburner chamber cause heating of the heat transfer chamber. The primary chamber has a heat conductive floor superimposed over the heat transfer chamber so that conductive and convective heating of the primary chamber occur. At least one primary auger is located crosswise in the primary chamber between a sludge feed hopper and an ash hopper. The heat transfer chamber underlies the primary auger near the end at the ash hopper.

Description

FIELD OF THE INVENTION[0001]This invention relates to incinerators and the like for processing biomass waste, and particularly biomass sludge and sludge-like matter such as animal manure or other sewage sludge, and the like.BACKGROUND OF THE INVENTION[0002]It is necessary that various biomass sludges, particularly such as animal manure from factory farms where perhaps many thousands of animals are raised for purposes of slaughter, should be properly processed so that they are reduced to inert, sterile material. It can happen that these forms of biomass and other related volatile solids may have infectious or even deadly bacteria or viruses in them, which must be destroyed. Animal manure may have a significant quantity of water, but may also comprise large percentages of hydrogen, carbon, and also a number of trace elements, such as nitrogen, sulphur, iron, chlorine, magnesium, manganese, sodium and potassium, among others. It is desirable to heat all of these materials so that the o...

AI Technical Summary

Benefits of technology

[0073]It will be noted that the 90° corner has a “corner to corner” distance that is greater than the width of the afterburner chamber, so as to thereby effectively increase the cross-sectional area of the afterburner chamber at that point.

Problems solved by technology

If the external heat energy introduced into the biomass material is at a very high temperature or is applied very abruptly, especially in a concentrated area, then two things tend to happen: Firstly, any reactions that occur tend to be rather violent, thus causing the production of fly-ash into the fumes of the volatilizing biomass; secondly, the sudden and concentrated reactions produce a large amount of heat energy, which in turn can cause the abrupt volatilization of the surrounding material, which volatilization can be somewhat violent.

Further, if a substantial amount of material is volatilized, in the manner discussed immediately above, over a relatively short period of time, then the ambient temperature of the primary chamber will tend to rise substantially, thus causing the remaining biomass to be volatilized more quickly, but not at a controlled rate.

In other words, the reaction is, at least to some degree, out of control.

It is found, however, that the fumes that are driven off contain a great quantity of materials, such as fly-ash, having hydrogen-carbon bonds, and other unincinerated materials.

However, relatively large pieces of material, such as fly-ash, may contain several million or billion molecules; and, accordingly, such pieces of material as are borne by the fumes may not get fully incinerated in the time that they take to pass through the afterburner chamber 7.

The flame tends to cause the biomass waste to inflame and also tends to physically agitate the biomass 4.

As a result, an undesirably high amount of fly-ash is included within the fumes from the burning biomass 4.

Further, this type of conventional prior art incinerator 1 does not provide sufficient heat intensity on an overall basis to properly incinerate all of the waste material.

There is often not enough heat intensity to cause complete gasification even of the materials that do burn, and certainly not enough heat intensity to cause complete gasification of the waste material at the centre of the biomass.

It has been found that typically there is also undesirable material such as dioxins, furans and organo-chlorides, and other organic matter.

Such incineration by way of direct radiant heat tends to cause burning of the biomass 9 so as to cause premature ignition which leads to incomplete combustion in the early stages of the process.

The firing of this burner can cause instability in the primary chamber and cause the emission of fly-ash material.

Such incomplete gasification is generally unacceptable as this material might include hydro-carbons, dioxins, furans, and other unwanted organic matter such as bacteria, viruses, and other micro-organisms.

It has been found that the use of such multiple control systems tends to produce an overall system wherein the temperature in the primary chamber may vary and, therefore, cannot be considered stable.

Such lack of stability is caused by the plurality of control systems essentially working against each other.

It has been found that such prior art incinerators and cremators as discussed above, due to the inherent nature of the incineration process that occurs, produce an unacceptable end product.

The fumes that are produced have relatively high levels of hydro-carbons, dioxins, furans, among other materials and substances, and also may contain fly-ash, while the resulting ash remaining in the incinerator may have unwanted organic matter such as bacteria, viruses, and other microorganisms.

It can therefore be seen that incineration of biomass waste and related volatile solids is generally unacceptable as it does not render potentially infectious waste totally safe.

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