BRPI0900363A2 - vegetable industrial waste burning process, vegetable industrial waste burning equipment, steam generator boiler - Google Patents

Abstract

VEGETABLE INDUSTRIAL WASTE BURNING PROCESS, VEGETABLE INDUSTRIAL WASTE BURNING EQUIPMENT, STEAM GENERATING BOILER. The present invention relates to a process of burning industrial vegetable waste, such a burning equipment, and a steam generator boiler (1) which harnesses the heat capacity of the waste for energy generation without polluting the atmosphere. The present process is performed with viscosity control of the waste, which allows its complete burning, and the steam generated is used for power generation (4) through a generator (3).

Description

INDUSTRIAL VEGETABLE WASTE BURNING PROCESS, INDUSTRIAL VEGETABLE WASTE BURNING EQUIPMENT, STEAM GENERATING BOILER

The present invention relates to the use of plant industrial waste as a fuel, and such waste has never been considered for this purpose. In a first aspect, the invention aims at a burning process of vegetal industrial waste, for the utilization of its calorific capacity. In another aspect the invention is suitable equipment for burning industrial combustible vegetable waste typically used in a steam generator boiler.

Invention History

The following text refers to soy molasses and vinasse, without, however, excluding any other residues of similar characteristics containing any sugars (eg sugar cane) or substances (eg starch) which may be hydrolyzed to sugars, such as maize, beet, potato, castor, canola, sesame, peanut, palm, cotton, orange cascade, sunflower, etc., known to the man of the art and for which eventual adaptations for carrying out the invention are made without necessity. of exploratory tests.

As used herein, "molasses" is a sugar residue separated, for example by distillation, from the liquid solvent used to stop the bran resulting from crushing a vegetable (grain, seed, husk, etc.).

As is well known, to obtain soybean oil, the soybeans are pressed or extracted, separating the oil from the desolate cake. The cake, in turn, undergoes a heat treatment, dried, cooled and stored for later commercialization. This process yields a soybean meal which depending on the shell separation can range from 44 to 50% protein (moisture 12.5%).

The process for obtaining protein concentrate consists of one more step of extraction. The bran mentioned above is subjected to an extraction with a mixture of water and alcohol, obtaining the protein concentrate (protein 65 to 74% dry basis) and the micelle. The concentrate is pressed, heat-treated, dried, cooled and stored. It is mainly used for animal feed manufacturing. The micelle, which is a mixture of sugars, water and alcohol, proceeds for distillation, first separating the alcohol from the remaining liquid which returns to the process. Then it passes through a concentration to remove most of the water to melt between (30% - 80% solids)

Soybean molasses contains a high sugar-alcohol content and can therefore be fermented. The residue of this fermentation is what is called vinasse. This vinasse contains mainly sugar residues, very small bran to be captured by filter, residual lipids and ashes. Sugarcane molasses also contains sugars that are easily convertible into traditional fermentation alcohol. Both vinasse generated in the process of obtaining sugarcane alcohol as well as cane molasses can be concentrated for use as plant fuels such as molasses and dasoja vinasse.

The application of soybean molasses as an additive in animal feed is known. However, most of this molasses is a waste that until now has been considered an undesirable by-product due to the difficulty of marketing it and the lack of storage space.

One option for discarding molasses would be to burn it. However, it is not possible to burn them in conventional devices without making several adjustments that were discovered as the molasses burned for a longer period, and it was possible to identify the problems. A number of problems arose which prevented the burning of this residue for more than 2 hours: the atomized molasses could not be heated in the burner, and temperature, concentration and viscosity control could not be achieved. consequent combustion control. These difficulties prevented molasses from being sent into the burner, preventing tests to be carried out to determine which concentration, temperature and viscosity would be best for complete combustion.

In the process of burning the BPF oil it is not necessary to control viscosity and concentration, as these parameters are guaranteed by the fuel supplier. There is no difficulty in heating, as conventional heat exchangers can heat the oil without problems of fouling and crystallization of sugars.

For some residues, such as molasses, this does not occur, because when the sugar passes about 60 degrees, it burns, crystallizing and eventually turning into coal, this coal incrustates in the inner piping pipe, losing the fuel and preventing the burning. At temperatures below 60 ° C the combustion is incomplete as it does not make it possible to heat molasses as necessary nor to maintain viscosity at a value between 50 to 70 centistokes. This value was found after making a battery of O2, CO2 and CO measurement tests.

The solution found was to inject steam directly into the molasses, with high speed through injectors, heating up to about 100 degrees without presenting any problem that, followed by a viscometer measures the viscosity in real time sending a signal to open or close a valve. steam control on the injector, according to the set point adopted. This molasses goes to a six pack and is sent straight to the burner. These controls made it possible to develop this firing process, with better molasses temperature, viscosity and concentration.

Another problem encountered due to molasses burning is the generation of a highly soluble and hygroscopic white ash. This ash impregnated in all areas of boiler heat exchange as well as in ducts, hoods (furnace, evaporator, superheater). This ash accumulates in the exchange areas and after two hours the temperature of the gases at the furnace outlet, which should never exceed 420 ° C, reached values of 550 ° C. The accumulation also happens in areas that are no longer thermal debris such as : boiler outlet ducts, pre-air, economizers, multicycle, hoods. This accumulation over time will increase the pressure drop on all these equipments, consuming all the hood making it impossible to burn for more than a week.

The solution found for impregnation in the trochanteric areas (furnace, evaporator, superheater) was the installation of sootblowers. In each area was determined a model that would have a better yield. Two blowing pressures were tested: 12 and 21 Kgf / cm2 It was found that at 12 Kgf / cm2 the gas temperature at the furnace outlet to 440 ° C and 21 Kgf / cm2 for 390 ° C.

In areas that are no longer heat exchange such as boiler outlet ducts, pre-air, economizers, multicycle, threaded hoods and rotary valves were made by removing these ashes directly to a bucket.

After adjusting these parameters a good result was obtained.

Another characteristic of molasses is that its burning occurs commemoration of many pollutants, causing damage to the environment. In addition, it can only be burned in blast furnaces at a temperature of about 1300 degrees centigrade, which is a costly procedure without any advantage in the harvesting cycle of the original plant.

It was then noted that the burning process caused another problem, which was the emission of smoke with particulate matter above 5000mg / m3 of gas, with a fine white dust (ash) dragged directly into the atmosphere, outside the legally permitted limits. .

Unlike other biomass fuels, where most of the ashes are insoluble, molasses ashes are soluble, so the solution to prevent their emission into the atmosphere must be different.

A first attempt to reduce this particulate emission was the use of a multicyclone and a water spray nozzle scrubber. However, when the molasses was burned again, it was noted that the multicyclone plus the scrubber was able to reduce the particulate gas from 5000 mg / Nm3 to 2500 mg / Nm3, but did not reach the 400 mg / Nm3 required by the IAP. It was also noted that over time the white ash clogged the multicycle, and the only way to continue was to wash every 3 days, ie not leaving the process continuous, making the project unviable.

As a result of the firing process, it was found that this was because gas scrubbing equipment, which is very common in the sugar and alcohol industry, only removes water-insoluble particulates contained in the gases, so that soluble particulates passed through the scrubber without being removed.

It was decided to start the multicycle and change the type of washer.

A venturi scrubber was then used to make a very efficient mixture of gases with liquid promoting both the capture of soluble solids and insoluble solids, followed by a cyclonic separator, a degouge separator and a mist separator installed on top of the cyclonic separator. A saturation lance was installed prior to the venturi to promote boiler gas saturation prior to venturi entry, soluble and insoluble solids would be captured in the latter, and the gas would exit the saturated washer with water containing soluble and insoluble solids. Excess water would be separated by the cyclonic separator, drops larger than 25 microns would be removed by the first drop separator, and drops (fog) larger than 3 microns would be separated by the mist separator (Demister), dragging the soluble particulate with it and releasing it. in the atmosphere the molasses burning gases with concentration below the required by the IAP.

Description of the invention

In the search for alternatives to use molasses and / or vinasse, particularly for soybeans, it was surprisingly found that this residue can be burned as fuel. In particular, molasses and / or soybean may be used as fuel in steam-generating boilers, in place of fossil fuels such as GMP oil or any other commonly used for this purpose, with the advantage of avoiding the accumulation of a by-product until the moment is considered wasteful polluting of little use, using advantageously the calorific power of the same, generating economy in the replacement of nobler and lighter fuels.

In a first aspect the present invention deals with a molasses and / or vinasse burning process, characterized by the following steps:

concentrate a molasses, vinasse or mixture thereof until the solids content is between 30 and 85%;

preheat to 60 to 100 ° C until a viscosity is achieved that is sufficient to completely burn in the burner;

burn in a flame burner by fogging.

In particular, but without excluding any other conditions, the following aspects are advantageously applicable:

molasses, vinasse or mixtures thereof are made from soya or sugar cane;

the solids content of molasses, vinasse or mixtures thereof is between 60 and 80%;

preheating is by direct steam injection;

preheating is done to about 100 ° C; and the viscosity of molasses and / or heated vinasse is between 30 and 80 cst (centistokes).

The burner is the same type commonly used for BPF oil and gas, for example Saacke SSB-S200 E-609 E-610 series burner.

It was found that obtaining complete combustion of molasses and / or vinasse is favored in the mentioned viscosity ranges, with expected variations depending on the plant origin of this new fuel. It has also been found that the calorific value obtained is greater than that of burning solid fuel as a chip.

Within another aspect of the invention there is also contemplated molasses burning equipment comprising:

- a molasses and / or vinasse containment vessel;

- a pump for pumping molasses and / or vinasse to a direct steam injection device;

- a direct steam injection device within molasses and / or vinasse;

- a viscosity checking and control device associated with a direct steam injection device;

- a pump to pump molasses and / or vinasse to a burner; and,

- a nebulized liquid fuel burner.

The equipment of the invention operates as follows: the molasses and / or vinasse, with a solids content of between 30 and 85%, is placed in a vessel which allows its direct heating by steam - the steam injector device may be self-contained or may be a built-in device. to the vase. The molasses and / or vinasse hazard is higher than adequate for full burning, so steam is injected until the viscosity drops to the proper range, typically between 40 and 80 cst, after which the liquid is pumped to the burner. The apparatus of the invention comprises a viscosity control and control device, for example a viscometer and a pipe and valve set that can return the pumped liquid to the vessel if the viscosity is higher or lower, as well as a specific actuator capable of acting on direct steam injector into the melting and / or vinasse mass, increasing or decreasing the amount of steam to increase or decrease viscosity as required. Precisioning and viscosity control devices for this purpose are known to the man of the art, so that their specific detail is not an essential aspect of the invention.

The liquid fuel burner device of the invention equipment is known in the state of the art, associated with an air compressor to allow the nebulization of the fuel. Advantageously, such a device may also concomitantly burn gaseous fuel, such as LPG, when it is desired to supplement molasses and / or vinasse burning.

The equipment of the invention is typically associated with a steam generator boiler. In such a configuration such a boiler may be multi-fuel, may contain various molasses and / or vinasse burners, soot blowers, etc. Such a boiler may be provided with a variety of additional devices, such as a solid department emission control system, according to the legal requirement of the region where the process is being carried out.

Advantageously, the steam generated in the boiler is sent to an energy generating turbine, which can be used in the production process that generated the vegetable waste, making the factory system self-sufficient.

Preferably, the equipment further comprises sootblowers that allow the inside of the boiler to be cleaned, for example, once per hour, without cleaning stops, improving combustion.

Suitably, without excluding any other, such a solid particle emission control system minimally comprises a venturidentro from which the flue gases and water are subjected to intense contact; and a cyclonic separator, a drop separator and a fog separator where mist is sent after passing through the venturi.

Alternatively to the use of a venturi, there is a washer with water absorption or pumping columns.

An exemplary embodiment of the invention is given hereinafter for illustrative purposes only, without imposing any limitation on its scope beyond that expressed in the appended claims. The image is schematic, without dimensions or proportions that correspond to reality, since its purpose is merely to clarify didactically an embodiment of the invention.

Example

The attached figure 1 schematically illustrates an installation where the burning of soy molasses occurs, its transformation into steam in a boiler (1), 12Kgf / cm2 steam turbine extraction (2) and 1.5 Kgf / exhaust steam. cm 2; and later generation of electricity (4) through a generator (3). The micelle from sugar extraction (not shown) enters a 4-stage apparatus called molasses concentrator (8) that sends molasses to a lung tank (10). With the aid of steam the micelle is concentrated to 80 brix before being sent to the tank (10). The amount of vapor injected into the concentrator (8) is controlled by a brix meter (9) at the concentrator outlet (8) which opens or closes a steam valve (7) according to the desired concentration. This 80 brix concentrated molasses is then sent to a lung tank (10). Molasses is concentrated to remove water, because what matters for burning is dry matter (Carbon, Hydrogen, Sulfur and Nitrogen). Through pumps (11) and (12) molasses is sent to the tanks (19) and (20) and to the injectors (13) and (14) where it is heated by direct steam injection. The amount of steam injected is controlled by the control valves (15) and (16) which receive signal from the viscosity meters (17) and (18), respectively. If the viscosity is high, the meters (17) and (18) have said valves open, and if the demand is low, depending on the set point chosen. Pumps (21) and (22) pump molasses to burners (Q2) and (Q1) with adjusted concentration, pressure, temperature and viscosity.

In this particular example, the steam generated by the boiler (1) has a pressure of 42 kgf / cm2 and exits through a pipe towards a turbine (2), where the 12 kgf / cm2 exhaust and 1.5kgf / exhaust vapors are extracted. cm2. This lowering of vapor pressure enables the generation of electrical energy (3). Thus there are two lines with extraction steam of 12kgf / cm2 (5) and exhaust of 1.5kgf / cm2 (6) directed to the molasses generating plant.

The boiler (1) can also generate steam with other fuels as it is provided with a grid (23) for the solid fuel support, such as the sow or soybean hull.

Burners (Q1) and (Q2) are also equipped with lances that can burn gas.

The boiler (1) is also provided with a soot blower (not shown), which is a rotary steam injector designed to remove any scale within the boiler.

The gases resulting from the boiler molasses burning (1) flow into a particulate material control system.

Said particulate material control system is composed of a saturation lance (24), a venturi washer (25), a cyclonic separator (26), a drop separator (27) and a mist separator (28).

Upon exiting the boiler (1), the burning vapors, through the desaturation lance (24), receive an amount of water that allows their saturation. After saturation they enter the venturi washer (25), where all the material is washed and captured. by injecting water into the venturi washer (25). The gases enter the bottom of a cyclonic separator (26), where centrifugal force separates the amount of coarse water injected into these gases.

This water comes out with insoluble solids and a part of soluble solids. The gases still continue with droplets that solubilize the soluble solids and the chimney outlet (30), if measured, appears as particulate matter. Still within the body of the cyclonic separator (26), the gases pass through a drop separator (27) that captures drops larger than 25 microns, moving to another mist separator (28) that captures drops larger than 3 microns. Thus, the gases leaving the cyclonic separator (26) are within the limits accepted by the environmental agency. The man of the art, with the aid of the aquitrazido teachings, as well as the example and the attached figure, will understand the invention and will be able to realize it. equivalently, not expressly described, but within all functions and result as learned herein, and which are protected by the appended claims.

Claims (14)

1. PROCESS OF BURNING INDUSTRIAL VEGETABLE WASTE characterized by the fact that it comprises the steps of: a. concentrate a molasses, vinasse or mixture thereof to a solids content of between 30 and 85% b. preheat to 60 to 100 ° C until adequate viscosity is achieved for complete burner burning; and, c. burn in a flame burner by fogging. Process according to Claim 1, characterized in that the molasses, vinasse or mixtures thereof are made from soy, sugar cane or other residues containing sugar or substances which can be converted into sugar by chemical hydrolysis. or enzymatic. Process according to Claim 1, characterized in that the solids content of molasses, vinasse or mixtures is between 30 and 80%. Process according to Claim 1, characterized in that the preheating is effected by direct injection of steam into the molasses mass and / or vinasse via injector. Process according to Claim 1, characterized in that the preheating is carried out to about 100 ° C. Process according to Claim 1, characterized in that the viscosity of the molasses and / or vinasse is between 30 and 80 centistokes. Process according to Claim 1, characterized in that the burner is of the Saacke type SSB-S200 series E-609 E-610. 8. VEGETABLE INDUSTRIAL WASTE BURNING EQUIPMENT characterized by: a. a molasses and / or vinasse lung tank (10), and molasses dokans at the appropriate viscosity for burning (19) and (20); two burners (Q1) and (Q2) of liquid-vaporized fuel c. two viscosity or temperature meters (17) and (18) for measuring the viscosity or temperature of molasses and / or vinasse brought to the burnout; two direct steam injection devices (13) and (14) within the molasses and / or vinasse; Two pumps (11) and (12) for pumping molasses and eavesdropping for injectors (13) and (14) and viscometers (17) and (18); two control valves for controlling the amount of vapor injected into molasses or vinasse (15) and (16) g. Two pumps (21) and (22) for pumping molasses and / or hearth to the burners (Q2) and (Q1), respectively. Equipment according to claim 8, characterized in that the liquid fuel burners (Q1) and (Q2) can simultaneously burn gaseous fuel. STEAM GENERATING BOILER, characterized in that it comprises at least one molasses and / or vinasse burning equipment according to one of claims 8 or 9. Boiler according to claim 10, characterized in that it is multi-fuel, the solid fuel being hull or soybean hull. BOILER according to Claim 10, characterized in that it has soot blowers. Boiler according to Claim 10, characterized in that it has a solid particle emission control system comprising a system which removes soluble and insoluble material consisting of a venturi scrubber (25), a cyclonic separator (26) and separators. fog (28). Boiler according to claim 10, characterized in that it has a solid particle emission control system comprising a washer such as absorption or bubbling columns, a cyclonic separator (26) and mist separators (28).