CA2061873A1 - Procedure for the manufacture of a solid combustible material based on solid urban and/or industrial waste and assimilable to urban and/or agricultural - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Procedure to manufacture a solid combustible material based on solid urban waste and/or industrial waste assimilable to urban and/or agricultural waste, in which the said waste, cleaned of contaminating metallic materials and glass, is ground to obtain a granulated product containing quicklime combined with the original water forming calcium hydroxide with minimum carbonate during the process and treatment with water steam at pressures of 1 to 20 atmospheres; its layer drying being carried out with hot air without CO2 at temperatures between 100 and 200°C.
so that the humdity decreases from the original of 1.5 to 1% by weight.

Description

2 ~ 7 3 PROCEDUR~ ~OR THB MANUFACTURE OF A SOLID COMBUSTIBL~ M~TERIAh BAS~p_Q~
SOLID UR~ A~L~ RUSTRIAL WAST~ A~ AS~INIhABLE TO pR~AN A~LQe AGR~L~URAL
DBscRIp~IQ~
The present invention refers to a procedure to manufacture, based on solid urban waste (S.U.W.) and solid industxial waste assimilable to urban waste ~S.I.W.~.U.), a material that can be used as fuel for electrical power plants, cement factories, etc..
Today, with the increase in population there is a proportional lncrease in the question of the elimination of all types of waste material from industrial production in mining, industry and also the elimination of solid urban wa~te (S.U.~.) and solid industrial waste as~imilable to urban waste (S.I.N.A.U.); solid urban waste (S.U.W.) is e~timated at a mini = of 1 kg per person/day. In the case of Spain, this amount can be calculated at 14xl06 t per year.
The lack of rubbish tip~ and the problems these involve, as well as the lac~ of fuels, are tuo problems that arise today. In order to offer an acceptable solution for these problems it i8 proposed to transform solid urban waste (S.U.W.) and solid industrial waste assimilable to urban waste (S.I.W.A.U.), following grinding and the removal of glass, metal elements, humidity and undergoing a thermo-chemical treatment, with solid, shaped material that can be transported and stored, and which can be used as fuel in electrical power plants, cement factories, and similar.
STUDY OF PR~VIOUS PATBNTS
There are varlous patents that carry out pyrolysis of organic residues and mix carbonized products, such as the French 2376B94 dated 78.09.08 and also 2369505-7806Ø Also the burning of organic material on a fluld bed is patented ~y the NIPPON ST~L CORP. under patent ~P 53049001 dated 78.05.04. The products of combustion are polymerized and pyrolized, adding other fuels with an auxiliary burner.
In some cases limestone is added as a desulphurer and slag remover, as in US patent 4078914 dated 7B.03.14 and US patent 410386 of 89.09.20 with drying prior to pyrolysis at 240-700DF. However, this is not cited when used to make compost since we believe that this i8 only a partial solution in US patent 356224 of 89.05.24. The use of water steam under pressure to recover latent heat in order to dry 20~1~73 supercrltical temperatures and subcritlcal pressures, is covered in US
patent 294424 of 89.01.09.
Nelther do ~e consider the incineration procs~ ln US pateDes such as 176782 dated 88.04.01 nor US 18.0~79 of 88.04.13, nor US
293546 of 89.01.03.
In so~e processea such a~ that oE US patent 399295, pre-drying is carrled out that reduces humidlty to 8-10% by compres81On and brlquetting as an original item. The fusion of the ash obtained i8 claimed in US patent 132058 of 80.03.20, using combustlon on a filter bed at high temperatures and passing through the aah.
The use of an atmospheric pressuxe reductlon allows a positlve air flo~ and avoids problems for persormel. The use of limestone as an outlet gas acrubber is used ln patent PB 2846032 dsted 80.04.30.
In the Itallan patent 105230 of recent date 85.10.28, urban waste is pulverlzed and drled at a predetermined level to avoid the production of fungi and possible fermentations. Specific chemical ~rodurts are added to avoid the production of toxic gases in later combustion of the pelleted product.
To summarise, from some 100 patents previously examined, the ma~ority end by using direct incineration of urban waste.
In some cases the outlet gases are purlfied ~ith lime~tone, mainly to eliminate the S02. In various cases urban ~aste 18 used for the blocatalysls producers of Methane and Bydrogen. Pyrolysls 18 used in many cases. Ihe fllter bed and prior ~eparation of metals ara profusely patented for the production of energy in direct boilers and without other treatments. Prlor drying is carried out by briquetting or in a scarcely defined form in the mentioned Italian patent.
The application for French patent N 2~72.421 describes a treatment process for urban rubb~sh to artificial aggregates.
To do this, the metallic elements are removed and a reaction is caused in the resulting mass that may have 30~ celluloae and humidities between 20 and 45~, with quic~lime and/or calclum salt at temperatures of between 250C and 450C, 80 that a dust-like product is obtained that i8 agglomerated by compres~ion after the addition o~
a binder to form granulea. The same patent N 2472.421 also indicates that the granules are sub~ected to a flnal thermal treatment, or following the abov~, at temperatures between 150C and 350C ~ith sufficient duration to heat them completely thro~gh. The preconceived 2 ~ 13 binder i~ a mixture of monocalclum pho~phate, chal~, urea, casein, bone gum and polyvinyl acetate. The patent indicate~ that charges can be incorporated YUC}l a~ indu~trlal wa~te, resin~ and sllicate~.
However, it does not preconcelve or claim its u~e as in our case as combustible material.
If combustible materials are usecl as boilers, there are numerous patents that uae urkan waste, but in no case do they u~e drying except in Brltish patent 1597443 of 81-09-09 in which, following ballistlc clas~ification followed by humidificati.on and drylng, pelleting wlth a polyethylene and lignite agglonerate. In ~ritish patent 1604948 of ~1.12.16 there i~ also a separation of metals and also of plastics and glass, and the alchols are used obtalned from the fermentatlon as fuels.
The procedures in accordance with the technique~ explalned above are not co~pletely satisfactory. Particularly because the use of energy to ellminate the water i8 lost and thls increases the corroaive properties of some gases glven off during combustion, auch as S02, NOx and ~Cl meaning that in our case they co~blne ~ith the Calcium Hydroxide contained in the resulting material thus dlmlnishing the possible corrosion by heating elements ln the stea~ boiler~, ~hlle decreasing possible contaminating aromatlc, orga~ic, blphenol and chlorate compounds such aa furanea and di~xines, a~ 1~ desirable ln a fuel for electrlcal power plants.
On the other hand, its blological stability is importa~t slnce its previous contaminating potential is eli~inated and lt remalns odourless.
The present Inveneion has the objectlve of offering a procedure that allows a materlal to be obtained that presents, as we have said, an optimum combinatlon of blological and phy~ical chemical propertles that are particularly useful for its use as a fuel material for electrlcsl power plants, cement factories, etc..

2 ~ 7 3 PRQCB~URE FOR TH~ M~NUF~UR~ OF A COMBUSTIBL~ M~TRRLA~_8e~ Q~ SOLI~
UR~AN A~ SOLID INDUSTRIAL WAST~ ASSIMILAB~ ~Q ~N W~s~E
Solid urban waste (S.U.W) and solid industrlal waste assimllabla to urban waste (S.I.~.A.U) are ground, ferro-magnetlc material~ are removed, lt is then ground to smaller~ si2e, glass and para-magnetic materials are removed, and quicklime and water steam added u~lng a worm. It is dried bet~een 100C and 200C BO that the maximum temperature is less than the flame point of combu~ti~le materials that may be found in the urban waste, particularly i~ they are already partially dried, i.e. their ~ater content iB lo~er than 1~. The outlet temperature from the drying oven must be near to the boiling point of water - 100C to obtain mdximum output from drylng at normal presRure .
Thi3 materlnl is reground and can be used as fuel in electrical power plants with the advantages of: containing no humidlty, being stable, odourle~s, tranRportable, not giving off or havlng a ~lnimum of toxic products during combustion and decreasing corrosion in the steam producing system in poYer plants. Ihe ash obtained from combustion can be used to manufacture cement (a~ a rau material), to clean smoke or as additives for portland cement.
The procedure according to the invention 18 characterized because solid urban ~aste (S.U.N.) and solid industrial ~aste assimilable to urban wa~te (S.I.W.A.U.) are mixed ~ithout containing contaminating metallic materials and glass, Yith a powdered mineral material containing calcium oxide.
The mixture thus obtained i~ treated ~ith water steam at high temperature, 100C - 200C, in order to destroy the organic structure of the materials composing the solid urban waste tS.U.W.) and solld industrial waste assimilable to urban uaste (S.I.W.A.U.), protelns, fats and mainly carbohydrates, and to ma~e easier their later shaping through lamination between rollers, in order to increase their den~ity and make eæaier their later drying uhich is carried out in a rotating oven uith internal helicoidal track ts aid the inter~al advance of the material. Drylng is carried out by hot air without C02 and causes an exchange with the ~ater steam, thus avoiding the carbonating of the Calcium ~ydroxide formed by the reaction of the uater with the quic~lime, and mairltaining the chemical-biological properti~s o~ the materials.

2~fil~73 According to the basia of the lnvention, this irJdlcates that the combination of the thermal treatment Yith ~licklime, the ~haped material obtained by lamination under presaure from a mixture of waat~
materials ground with quicklime, and fr a aecond grinding process under pre~ure of the product obtained following thermal treatment, confers the properties necessary for itEI transport and storage such a~
density, absence of odour, optimum si2e, no biological degradables, etc~.
Surprisingly, it has been noted that this group o~ operations allows a combustible product to be obtained that presents biological inertia, a notable decrea~e in corrosion possibilities for combustlon installations and an important decrease in the production of polluting gases. Due to their lime content, the ash may be u~ed to ellminate gases in depuration systems, as raw material in the production of cement, with a decrease in energy consumption, or a~ pozzolanlc material for adding to portland cement.
The lime may also come from calcinated dolomite~, i.e. lt0 content in Magnesium Oxide i8 not exactly a problem. Its percentage ~ill vary between ~% and 8%, with contents of 5~ of dry material being preferred. That the material - urban waste or industrial waste assimilable to urban waste - i9 bacterlologically co~taminated, is not a problem for its use since the sterilizing process using temperatures or Yater steam pressure, the addition of quicklime and the lster drying at 200C, impede any vital process.
In order to understand the in~ention, a description i~ given below with reference to the attached drawing, for carrying out the treatment of solid urban waste, solid industrial waste sssimilable to urban and/or agricultural ~aste to transform it into industrial fuel or similar.
In this case, the classic, prior treatment is carried out of grinding 1 and 2, breaking down to small ~izes of some 10 cm and magnetic separation 3, and later a further grinding to ~izes of 1 cm 4. ~ollowing density separation 5 of ceramics, glass and paramagnetic metals, and combination with quicklime in a uorm 6, the product in the worm undergoes the action of water steam at 100C-200C in the same worm 7, which desegregate~ and breaks down the cellular membranes in the organic part of the waste, principally proteins or carbohydrate~.
The worm acts simultaneously as a mixer, transporter and compressor.

2 ~ 7 ~

This part of the process increases the denslty of the material that, after shaping, decreases the ~ize of the prior drying system, and furthermore substances are formed with s~me sllght binding or agglutinant po~ers - such as the change of starches to de~trines -that permi~ the step through the laminators without 1088 of ~hape.
Furthermore, treatment with water steam at pressures of U,l - 2 N/mm2 causes the total destruction of bacteria, viruses and fungi and other contaminating organi~ms that are or may be co~tained in the urban waste. The quickllme contributes to this mlssion and according to the strongly basic p~ produced impedes the possibility of the waste serving after treatment a~ food for rodents or in~ects. Th2 drying temperature and lo~ flnal humidity content contrlbute to thi~
antiv~tal process.
Thereafter at the end of the worm the mater~al enters a ~erles of four pairs of lamination cylinders 8 in a horizontal po~ition, ~ith spaces of 1,5 cm, 1 cm, 0,5 cm and 0,25 cm, ~ith the ~os~ibility of separation by spring actlon with springs placed on their axls perpendicularly to the direction of passage of the material, in order to allow the passing of possible voluminous and non-compressible substances. These cylinders act as molder-shaper~ and re~Gve exce~e humidity.
In this manner the density of the waste increa~e~ from 0,1 g~ml to 0,4 g/ml and in some cases to 1 g/ml, and humidlty decr~asea frcm 30~ to 15~, the product then goes for some 20 to 30 miDutes to a drying oven in an a~ial direction through the said rotating tubular oven 9, placed with its rotating axis in a practically horizontal positlon, or ~ith a slight slope in the directio~ of advance of the materials in the oven, and with lnternal hel$coida1 paths.
Drylng in the oven is carried out using hot air at te~peratures of 100C to 2000C, thus avolding carbonation of the lime and contamination by C02 and an increase in drying output since the products of fuel co~bustion, C02 and H20, are not ln contact and therefore the air is less humid. The hot air causes an exchange of residual water steam of low enthalpy - air and thus the water steam i8 used without any other possible use due to lts low enthalpy. The dried product, with a humldlty of 1%, can be formed lnto squares or rounds when it leaves the worm using a ~eries of rollers simllar to those at the entrance 10. Shaplng 18 alded by the Calclu~ Hydroxlde 2~373 present that act~ as a binder, simultaneously with th~ calcium soaps formed that aid ln decreasing dra~ing friction.
Another variation iB the shaping ln cylinders uslng a granulator 11 that acts at high pressure of some 600 bars. The shaped product is stored under cover indeflnltely untll used as fuel. It~ upper calorific power is in the order of an average o~ more than 3.500 Kcal/kg. This fuel may be u~ed to advantage to produce water steaM
for heating use or also to move steam turbines. Combuation is carried out on a conventlonal fluid bed which gives good thermal outputs.
Furthermore, the ash produced can be used to advantage, with thermal energy saving since they are already partially active and need 1~B8 reaction heat in order to react with lime to produce tricalcium silicates as raw materlal for the productlon of portland cement clinXer, also for the production of silico-calcareou~ bricks, and alao as a po~zolanlc addltive since the heat it ha~ undergone during combustion and shaping, together with its lime conteDt, have activated ita po~zolanic properties. It hlgh lime content allou~ partlal recycling to substitute the lime originally added and also its use in smoke depuration. In the case of power plants, it ~ould decrease the final S0 content in the smoXe.
Reference is made below to a ser~es of practlcal e~a~ple~ of the invention:

A homogeneou~ mixture of ~aste is obtained wi~h a weight of BOme 945 r~g with an inltial humidity of some 30~ by ~ei~ht (obtained after having ~eparated 45 Rg of scrap from the initial mass of 1.000 Xg of urban waste, obtained directly from waste collection and a further 45 ~g of glass, bricXs, tile and various metals), to ~hich has been added 25 Kg of qulc~lime.
This mixture iB treated with air and~or ~ater steam at 150C and thereafter i~ shaped into parallelpipes or cylinders with 1 cm side or radius x 5 cm long approximately - using a hori~ontal system of shaping rollers. The mixture undergoe~ a water 108~ of 15~, with which the weight of the same on entering the oven is 795 Kg during drying aC 100C-200C.
These temperatures are obtalned by the passage of hot a~r produced, in turn, by exchange with water steam.

2 ~ 7 3 During the 30 minutes stay ln the drylng oven a further 14~ of water is lost and thus the resulting pro~uct ha~ a masa of 655 Kg approximately ~ith a humidlty content of 1%. Duri~g co~bustion this product can supply 3.895 Kcal a~d leave scme 163 ~g of a~h that may be used as pozzolan. This product can be ground for ea~e of tran~port and combustion under a pressure of some 600 bar~ using a rotating in-line roller granulator, to form cyllndrical bodies some ~ mm ~n diameter and with a length of between 10 and 20 mm.
It i8 al30 po3aible to give them the desired form by mak~ng the dried material pa3s through a series of cylinders that shape the material to the si~e required in parallelpipe or cylindrical shapes of similar sizes to tho3e on entering the oven.
These granules produced by either system are burned at temperatures above 850C for more than 2 ~econds and with 6~ minimum oxygen, in order to de3troy or impede the formation of chlorate to~ic compounds ~uch as dioxines or furanes on a fluid b~d to produce ~ater steam in a boiler at temperatures appropriate to move a ~team turbine that acti~ate3 an alternator in order to produce electrical energy.
The water steam ~ith less enthalpy is recycled for the treatment and drying of the ash produced and may also be partially reused due to its lime content, aR a decontamination or purificatioD material for combustion gases such a3 S0, NO~ and dioxines, and for the uses cited previously.
Bxam~le 2 In this case, starting ~ith 1.000 ~g of urban uaste with a humidity of 25%, 58 Rg of ferro-magnetic scrap, 60 xg of glass and 20 Xg of paramagnetic me~allic materials, mainly ccpper and aluminium together with porcelains, have been removed. 30 Rg of quicklime and 20 Kg of fluid bed ash have been added. ~fter the shaping and drying process has decreased humidity to 0,75~, giving a ~ater 1088 o~ 249 Rg, 662,7 Rg of dried granule3 are obtained that offer the pos~ibllity of producing 3.820 Rcal and giving 167 Kg of ash.
sxa~lel A similar pIocess is followed to those indicated in examples 1 and 2. It starts ~ith 1.000 Kg of urban ~aste containing 35~ humldity by weight and a content of 6~ ferric scrap, 5~ glass and 5~
paramagnetic scrap, porcelain, ash and brick. Follo~ing the addition of 25 Kg of quic~lime and drying of the remaining material to 1,5~

2 ~ 3 humidity, 530 Kg of grsnule~ are obtained that can produce 3.885 Xcal leaving an a~h content of 133 Kg following combu~tion in a fluid b~d.
Having ~ufficiently de~crlbed the nature of the invention and the manner of carrying lt out in practice, it ~hould be ~tated that the di~positions indlcated above and sho~n in the attached drawlng~
may be modified in their detail~ provided their fundamental principle i~ not altered.

Claims (10)

1. Procedure for the production of solid combustible material based on solid urban waste and/or industrial waste assimilable to urban and/or agricultural waste; characterized because the said waste, cleaned of contaminating metallic materials and glass, is ground to obtain a granulated or stick-shaped product containig quicklime combined with the orginal water forming calcium hydroxide the least carbonated possible during the process and treatment with water steam at pressures of 1 to 20 atmospheres; with later drying being carried out with hot air without CO2 at temperatures between 100 and 200°C, so that humidity decreases from the original 1,5 to 1% by weight

2. Procedure according to claim 1 characterized because the solid combustible material obtained produces during combustion 25% ash and more than 3500 Kcal/kg.

3. Procedure according to claim 1 characterized because the calcium oxide can also be used with magnesium oxide.

4. Procedure according to claims 1 and 2 characterized because the content of CaO is some 5% by dry weight of urban waste.

5. Procedure according to any of the above claims, characterized because the ash obtained from combustion on the fluid bed is incorporated in order to reduce the content of quicklime added to the waste.

6. Procedure according to any of the claims 1 to 4 characterized because the ash obtained during combustion is used as raw material to make cement clinker.

7. Procedure according to claims 1 to 4 characterized because the ash obtained from combustion is used as pozzolanic material.

8. Procedure according to claims 1 to 4 characterized because the ash from the fluid bed combustion of this fuel is used as a purifying agent for combustion gases to eliminate SO2, NOx and Furanes or dioxines.

9. Procedure according to claim 1 characterized because in order to granulate the product shaping cylinders are used with intermediate spaces of 1,5 to 0,25 cm.

10. Procedure according to claim 1 characterized because the combustible material is used in a fluid bed fuel installation.