EP0110875A1

EP0110875A1 - Process for the utilisation of organic waste materials and hydrogen from water electrolyse to produce gas with a controlled composition and calorific value

Info

Publication number: EP0110875A1
Application number: EP19820901835
Authority: EP
Inventors: Alcêo Antonio BRAGA LOPES
Original assignee: TECNOLUMEN ENGENHARIA Ltda
Current assignee: TECNOLUMEN ENGENHARIA Ltda
Priority date: 1982-06-04
Filing date: 1982-06-18
Publication date: 1984-06-20
Also published as: BR8203296A; WO1983004270A1

Abstract

Un procédé d'utilisation de matériaux organiques de déchets permettant de produire du gaz avec une composition et une énergie calorifique contrôlées consiste à transformer les matériaux organiques de déchets en gaz comprenant essentiellement H2 et CO par pyrolyse et à mélanger ces gaz avec le H2 produit dans une unité d'électrolyse.A method of using organic waste materials to produce gas with a controlled composition and calorific energy consists of transforming organic waste materials into gas comprising essentially H2 and CO by pyrolysis and mixing these gases with the H2 produced in an electrolysis unit.

Description

Process for the utilization of organic waste material and hydrogen from water elecrtrolise to produce gas with a controlled composition and calorific value.

Technical Field The invention relates to a process for the utilization of organic waste materials and hydrogen from water electrolisis to produce a mixture of gases. These mixtures, composed mainly of hydrogen (H2) and carbon monoxide (CO), have controlled compositions and calorific powers, owing to the different mixtures produced.

Many process have already been proposed for the production of gases. In almost all of these process the composition of the gases depend on only one raw material, so that the obtained gas has only one possible composition and has constant basic function characteristics (calorific value and reduction action).

Background of the Art In the prior art the conversion into gas from solid organic waste and some inorganic materials coming from municipal, industrial or agricultural refuses and from other sources, produces a gas with a composition which is composed mainly of carbon monoxide and carbon dioxide, hydrogen, traces of hydrocarbons, mechane and in addition to a reasonable amount of nitrogen. The calorific value and the reduction action of the gases will be decreased by the presence of inert nitrogen. Consequently the economic use of these gases is reduced in comparison to the gas produced by the present invention, which without nitrogen, necessitates a smaller volume of air for the combustion.

Accordingly the primary object of the present invention is to provide an improvement in the process for obtaining a controlled composition and calorific value gas, to be used depending on he cpmposition, in heating (domestic and industrial) or for propolling motors (explosion motor or reaction motor) or in reduction process (mineral reduction process, synthesis gas process, etc.) Disclosure of the invention The present invention benefits by two distinct technologies -water electrolisis and pyrolisis of materials, which are rich in carbon, hydrogen and have some of oxygen.

The production of hydrogen by the electrolisis process has been developed for many years. There have been units in operation for more than 50 years. In some places, where a electrical energy has competitive prices with derivative oil fuels, the production of hydrogen by eletrolisis competed with petroleum fuels before the 1973 crisis. Nowadays, obviously, the position of the production of hydrogen by electrolisis is better.

Ammonia producing units have been in operation for more than 50 years. In Assuwan, Egypt, one of the biggest ammonia producing units has been constructed, and has been operating since before the petroleum crisis. It produces ammonia for fertilizers based on urea. Such fertilizers have been used for the recuperation of the areas not flooded by the Nile River, since the regulation of the Assuwan dam.

As the element, which has highest calorific value by combustion, hydrogen has been the fuel for the spacecrafts, whose programs are indifferent to the petroleum crisis.

In table I are set forth some fuels, the calorific values of the gasificated fuels and their mixtures with air, necessary for combustion.

Table (I) - Calorific value of the gasificated fuels afther their mixture with the necessary air for combustion (approximate numbers)

On the other hand, the conventional process for the utilization of waste organic material - direct combustion and biodigestion - present respectively a find product, with a low calorific value and low convertion yield. The gas produced by pyrolisis of organic residues has a good yield and calorific value, near to that obtained by the natural gas combustion, for exemple, which is nowadays one of the biggest energy resources, although has a limited lifetime.

Through many experiences it was observed that the addition of hydrogen to the water gas improves its basic characterists. The hydrogen concentration is higher, so that the gas becomes more advantageous and easier in handling. The mixture is more employed with the presence of the carbon monoxide as a moderator, and the new process is enriched. Table (II) - Calorific value of some compositions of the mixture H2+CO, with sufficient air for its combustion.

Brief Description of the drawings The process of gas production of the invention will be more readily understood by referring to fig. 01, which is a schematic diagram and fig. 02, which is a operational fluxogram of the process. It will be understood that the invention is not limited to such figures and may be variously practised within it's scape.

The unit operations will now be described with reference to the drawings and with appropriate designations of the equipment.

Fig. 01 - Schematic flow plan of the arrangement of the units: An electric energy generators (1), that can be a hydroelectric station (1A) or a conventional substation (1B) or an ordinary lowering transformer (1C), produces energy for the electrolisis unit (2); the electrolisis unit receives treated water from the water-traiting unit (2.1) and is composed of different equipment and systems, including a lung storage tank of hydrogen and oxygen; the pyrolisis unit is composed of an area for the preparation of a wate organics materials: (3.1) and a furnace (3.2). The gases produced in the pyrolisis unit are conducted to a mixing and dosing unit. (4), which controls the addition of hydrogen .to obtain the deserable composition. The gas with a specific composition is conduced to the gasometer (5), which supplys the storage units (6) for the application of the gas.

Fluxogram of the process - fig. 02: Hydrogen line - the electrolisis unit receives water as raw material from a water treating unit, which receives untreated water from any available water sources (1.2); it consumes a continuous current from rectifyings (1.3) after receiving power from the substation (1.4).

The oxygen produced is employed in the pyrolisis furnace to correct the stequiometri reaction, when the amount of oxygen in the waste organic material is not sufficient to react with all necessary carbon to produced carbon monoxide (2); the surplus of oxygen is bottled (2.1) for other uses, including hospital, due to the purity of oxygens obtained by the electrolisis process. The hydrogen is conducted through it's own line (3) to the mixing-dosing unit, where it is mixed with the gas produced in the pyrolisis unit (5), so that the resultant gas will have the desirable composition and will be conduced to the gasometers (8).

Pyrolisis gas line - the waste organic material are selected and the inorganic materials are packed then leaped up in a covered area receiving area (5.1) and sold as scrap; as these waste meterials have high humidity, it is stored in a place where it permits the draining of a part of this humidity through a drainager system (5.2). The other part of the humidity is removed in the feeding system (5.3) which receives the gas from the pyrolisis furnace (5.5) and in the interior of the furnace, during the pre-heating, the low-humidity waste feeds a grinder (5.4) which breaks up the material in order to permit a homogenious feeding as well as facilitating it's combustion because of the increase of the contact surface; the necessary power for the system is supplied by the substation (1.4) which also supplies the electrolisis unit. The gases are removed from the furnace, after supplying the necessary heat for the reduction of the feed humidity, it can be directly burned in a system which does not demand the modification of it's calorific value or it can be conducted to the gasometer, the gas is conducted to the gasometer (6) after being cooled in an proper unit (6.1). From the gasometer, the gas is conducted to the mixing-dosing unit (4) which receives the right amount of hydrogen (3); the mixtures coith the desirable specification is conducted to the respective gasometer (8) and will supply the loading station (09) for the proper employment of the mixture.

One advantage of operating in accordance with the process defined will be the destination of the municipal, industrial, agricultural, etc. organic waste materials, which nowadays overloads the municipal administration gouvernment, on the verge of obtaining intermunicipal solutions such is to extent of the problem. A further advantage of the process will be for the regions without electric energy transmission lines, but with little waterfalls and large planted areas. In these cases the progress is limited by the high costs of the derivaters oil transported to such regions. In many municipalities the destination of agricultural residues (rice, corn, wheat, soybean, etc.) they have discussed which causes an impasse between the gouvernment and the farmer agriculturist.

Furthermore the benefit of the process will be enormous for the implantation or for the reinforcement of gas piping systems for industrial or domestic purposes, substituing the present structure supplied by oil derivatives . We call attention to the utilization of 700/800 kg of waste, which gives a gas with a calorific value of about 2,500 Kcal/Nm³, corresponding approximately to a substitution of 1.6 barrils of oil. We can conclude, from this, the great help the process will give in the search for oil substitutes.

In conclusion, we must remember that the utilization of energy according to this process, beyond the advantages alreadypointed out, will always provide a renewable energy, as long as there is earth's athmosphere and organic residues from our civilization.

Claims

Claims 1. Process fot the utilization of organic waste materials to produce synthesis gas with a controlled composition and a calorific power, which includes a pyrolisis process for the production of gases composed basically of H2 and CO, the improvement of this process comprises the complement of additional H2 from electrolisis to the gas mixture; and the final mixture will comprise of 49 to 80% of H2 and 47 to 17% of CO, with a calorific value equal to a more than 840 Kcal/Nm³, with a sufficient air for it's combustion. 2. A process as claimed in claim 1, wherein the raw material can be organic waste materials from public cleaming (domestic refuse or sweeping); refuses from cereal processing units, oily seeds, refuse from sugar cane cultivation or other cultivations; organic industrial refuses such as pieces of tyres, plastics, wood chips or sawdust or many other organic waste materials.