CN115948187A - Plant residue treatment method for fuel - Google Patents

Abstract

The invention discloses a plant residue treatment method for fuel, which relates to the technical field of plant residue treatment, and specifically comprises the steps of sending plant residues into a crushing machine for crushing treatment to obtain residue crushed materials; and dehydrating the crushed residue through a screw extrusion dehydrator to obtain a residue stock, conveying the residue stock into a mixing bin, adding conventional alkali and alcohol treatment liquid, and heating and stirring simultaneously to obtain the mixed alcohol-based fuel. The plant extraction residue and the alcohol treatment solution are combined to form the mixed alcohol-based liquid fuel, compared with the conventional incineration process which only uses the plant residue as the combustion fuel, the whole combustion process does not generate black smoke and coking, and simultaneously does not generate a large amount of incineration ash.

Description

Plant residue treatment method for fuel

Technical Field

The invention relates to the technical field of plant extraction residue treatment, in particular to a plant residue treatment method for fuel.

Background

The plant extract is a plant product which is formed by separating and purifying one or more active ingredients in plant raw materials by means of physics, chemistry, biology and the like and mainly takes biological micromolecules and macromolecules as main components, is an important component of the biological industry which takes biomass as raw materials to produce biological products, is widely applied to the production fields of medicines, food additives, functional foods, daily chemicals, plant pesticides, plant veterinary drugs and the like at present, and mostly takes traditional Chinese medicine plants as main raw materials. The content of the target active substances of the plant extracts is generally not high in plants, and in order to obtain a certain amount of plant extracts, a large amount of plant raw materials are required to be processed, and meanwhile, huge amount of waste is generated.

At present, plant residues extracted from the plant residues belong to wet materials, are extremely easy to rot and have strong irritating unpleasant odor, and if the plant residues cannot be treated in time, great hidden danger of pollution exists to the ecological environment; at present, the treatment methods of plant extraction residues mainly comprise modes of landfill, incineration, secondary processing and utilization and the like, and in the case of treatment of huge amounts of plant residues, the incineration is the main treatment way at present.

However, in the conventional incineration treatment, most of the residues are dehydrated and then directly incinerated or made into biomass particles or lump fuel, and the biomass particles or lump fuel are put into a special biomass boiler to be used as fuel. However, in this treatment method, since the plant residue itself still contains part of water (generally, extrusion dehydration treatment or high-temperature baking is adopted, but the high-temperature baking dehydration takes a long time and has high energy consumption, and is not applicable to huge residue treatment requirements, while the extrusion dehydration treatment can generally reach about 80-85% of dehydration rate in the conventional extrusion processing), under the condition of not mixing with other substances for combustion, a large smoke volume is generated, the heat loss of smoke is large, a stable combustion state is difficult to achieve, and the plant residue generates a lot of ash after burning out, and the furnace chamber also needs to be cleaned regularly.

And most importantly, the plant extraction residues have the characteristics of high chlorine, high alkali, high volatile matter, low ash melting point and the like, and are easy to corrode a boiler during combustion and generate slag bonding, coking and the like. The biomass fuel ash has high content of alkali metal, particularly potassium, and low ash melting point, and coking, corrosion and the like are easily generated on a water-cooled wall and a heating surface in a high-temperature state; in addition, a certain amount of chloride ions may be present in the ash, and chlorine and potassium may be directly deposited on the heat transfer surface in the form of potassium chloride, and may also react with silicates in the ash to form low-melting-point ash, which makes the tendency of coking and corrosion of the boiler worse.

We therefore propose a method of treating plant residues for fuel.

Disclosure of Invention

The invention provides a plant residue pretreatment method for fuel, aiming at the problems that the combustion stability of plant residues is not well controlled, the smoke discharge is large, a large amount of ash is generated in the treatment of a large amount of plant residues, a boiler is easy to corrode, coking is easy to occur and the like in the conventional plant residue incineration treatment method in the background art.

The invention discloses a plant residue treatment method for fuel, which comprises the following steps:

and sending the plant residues in the temporary storage bin into a crushing machine for crushing treatment to obtain residue crushed aggregates.

Conveying the residue crushed aggregates processed by the crushing machine into a screw extrusion dehydrator for dehydration treatment while heating through a heating type screw feeder to obtain residual liquid and residue stock with the moisture content not more than 10%, wherein the residual liquid is uniformly collected into a residual liquid collecting tank for storage and waiting for waste liquid treatment; and the residue is prepared for standby.

Feeding the prepared residue into a mixing bin, adding conventional alkali and alcohol treatment liquid, and simultaneously heating and stirring to neutralize and disperse the residue in the mixing bin; and obtaining the mixed alcohol-based fuel.

The mixed alcohol-based fuel is sent into a buffer bin and finally sent to a combustion furnace to serve as fuel through a pipeline pressurization system.

Furthermore, two screw extrusion dewaterers are sequentially arranged from front to back, a feed inlet of the second screw extrusion dewaterer is positioned at the bottom end of a discharge outlet of the first screw extrusion dewaterer, the height difference is kept between 60 cm and 70 cm, and a reinforcing steel bar blocking fork is further arranged inside the second screw extrusion dewaterer.

Furthermore, the heating type screw feeder adopts hot water as a heat conducting medium, and the hot water is from a hot water system for recycling boiler heat.

Further, the heating temperature of the residue crushed aggregates is 70-80 ℃.

Further, the conventional alkali includes, but is not limited to, aqueous solutions containing caustic soda, ammonia water, lime water, or the like.

Furthermore, before the residue crushed aggregates enter the mixing bin, sampling is carried out by taking batches as units to carry out acidity value detection, the sampling object is residual liquid extruded in dehydration processing, the input amount of conventional alkali is determined by the detected acid content, and the input amount is controlled by matching with a flow valve.

Further, the alcohol content in the alcohol treatment liquid is 75-80%, wherein the alcohol is a liquid containing various simple alcohols such as methanol and ethanol or polyhydric alcohols or an alcohol solid with a melting point lower than 90 ℃.

Furthermore, the adding amount of the alcohol treatment liquid is based on the fact that residue materials are not prepared, the temperature of the residue materials is kept at 75-85 ℃ when the residue materials are heated and stirred in a mixing bin, the duration time is 6-8 minutes, and the residue materials and the alkali-containing alcohol treatment liquid are subjected to neutralization and decomposition reaction at high temperature to obtain the mixed alcohol-based fuel.

Further, after the mixed alcohol-based fuel is stored in a buffer bin, the mixed alcohol-based fuel needs to be slowly stirred before being conveyed to a boiler system through a pressurized pipeline.

Compared with the prior art, the invention has the following beneficial effects:

the plant extraction residue and the alcohol treatment liquid are combined, and the plant extraction residue and the alcohol treatment liquid are heated and stirred, so that the plant residue can be effectively dispersed in the alcohol treatment liquid to form the mixed alcohol-based liquid fuel, and the treatment mode has the advantages that although the combustion heat value of the alcohol-based fuel is influenced to a certain extent for a small amount of moisture contained in the plant residue, the normal combustion of the alcohol-based fuel is not influenced, the combustion stability is easy to control, in addition, the mixed alcohol-based fuel formed by dispersing and decomposing the plant residue into the alcohol treatment liquid mainly generates water and carbon dioxide during the combustion, a small amount of insoluble substances can also float in the mixed alcohol-based fuel and can be sent into a boiler along with a pressurized pipeline system for combustion, and compared with the conventional incineration process which only uses the plant residue as the combustion fuel, the black smoke and coking can not be generated, meanwhile, a large amount of incineration ash can not be generated, in addition, the neutralization reaction is also carried out on the plant residue in the method, so that the pH value of the obtained mixed alcohol-based fuel can be close to or reach the neutrality, and the working medium can not have obvious corrosivity any more, and the plant residue can be used as the conventional boiler fuel.

According to the invention, the plant residues are further crushed by the crusher, and the plant residues are heated and softened to soften plant residue fibers, so that convenience is provided for subsequent double-screw extrusion dehydration processing, the dehydration rate of 5-10% can be improved on the basis of the dehydration efficiency of the conventional screw extrusion dehydrator, the plant residues can damage the residue fibers in the dehydration processing process, convenience is provided for the later-stage plant residues to be subjected to dispersion decomposition and neutralization reaction in the alcohol treatment liquid, and the fluidity of a small amount of insoluble substances in the mixed alcohol-based fuel can be improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a schematic view of the step structure of the present invention;

FIG. 2 is a schematic view showing the structure of the plant residue treatment process according to the present invention.

Detailed Description

In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the various embodiments of the invention. It should be understood, however, that these physical details should not be taken to limit the invention. That is, in some embodiments of the invention, such physical details are not necessary. In addition, for simplicity, some conventional structures and components are shown in the drawings in a simplified schematic manner.

Referring to fig. 1-2, in order to solve the problems of large smoke discharge, more ash generated by combustion, difficult control of combustion stability, easy corrosion to a boiler, easy coking in the boiler and the like when the plant extraction residue is used as a biomass fuel for combustion at present, the invention provides a plant residue treatment method for combining the plant extraction residue and an alcohol treatment solution to form a mixed alcohol-based fuel, performing neutralization treatment on the acidity of the mixed alcohol-based fuel, and reducing obvious corrosion to the boiler when the plant residue is burned, and specifically comprises the following steps:

as is known, in the current plant extraction process, the most initial raw material extraction is mostly carried out by two types of squeezing and distilling, and the two types of extraction means are different from each other according to different types of raw materials, such as rhizomes, barks, leaves, fruits or flower buds, particularly, the extracted raw materials are rhizomes and barks, the fiber retention integrity of the extracted raw materials is far higher than that of the leaves and the fruits, the subsequent dispersion and decomposition reaction and the squeezing and dewatering processing have certain influence.

In order to improve the dehydration efficiency in the traditional screw extrusion dehydration process at present, the residue crushed aggregates processed by a crusher are heated and conveyed to enter a screw extrusion dehydrator for dehydration treatment through a heating type screw feeder, the heating temperature of the residue crushed aggregates is 70-80 ℃, residue stock with residual liquid and water content not more than 10% is obtained, wherein the residual liquid is uniformly collected into a residual liquid collection tank for storage and waiting for waste liquid treatment; the preparation of the residue is ready for use, and the residue pieces are heated during the spiral conveying process, it is known that plants generally have much higher fiber flexibility after being heated than in a cooled or normal temperature or normal state, and the heated residue is more easily squeezed out of the water inside.

In order to combine the plant residues and the alcohol treatment liquid to form a mixed alcohol-based fuel, reduce the acid residual in the plant residues and obviously corrode a boiler in long-term combustion, after the residue prepared materials are sent into a mixing bin, the conventional alkali and the alcohol treatment liquid are added and heated and stirred simultaneously, wherein the heating and stirring mainly promote the neutralization and dispersion reaction of the conventional alkali and alcohol treatment liquid and the plant residues in the treatment bin; and finally obtaining the mixed alcohol-based fuel.

And finally, the mixed alcohol-based fuel is sent into a buffer bin and finally sent to a combustion furnace through a pipeline pressurization system to serve as fuel.

In order to further improve the dehydration efficiency of the plant residues, two screw extrusion dehydrators are sequentially arranged from front to back, a feed inlet of a second screw extrusion dehydrater is positioned at the bottom end of a discharge outlet of the first screw extrusion dehydrater, the height difference is kept between 60 and 70 centimeters, a steel bar blocking fork is further arranged in the second screw extrusion dehydrater, the height difference of the feeding and discharging of the second screw extrusion dehydrater is 60 to 70 centimeters, and the design of the steel bar blocking fork is matched, so that the plant residues subjected to primary extrusion dehydration can be subjected to solid material fixation and can be subjected to primary bulk material operation when falling into the second residue dehydration equipment, and convenience is provided for secondary plant residue dehydration.

The heating type spiral feeder adopts hot water as a heat-conducting medium, the hot water comes from a hot water system for boiler heat recovery and utilization, electric energy or other energy sources do not need to be additionally used, and the heat recovery and utilization rate is improved.

For cost saving purposes, conventional bases include, but are not limited to, aqueous solutions containing caustic soda, aqueous ammonia, or limewater; the alcohol content in the alcohol treatment solution is 75-80%, wherein the obtained alcohol is liquid containing various simple alcohols such as methanol and ethanol or polyhydric alcohols or solid alcohols with melting point lower than 90 deg.C, and the used alcohol can be recovered alcohol or waste alcohol for cost saving.

In the extraction process of each batch of plants, due to the influence of factors such as the quality of raw materials, the production place and the like, the pH value of each batch of residues cannot be unified, so the input amount of alkali is related to the neutralization reaction condition of the plant residues in the alcohol treatment liquid, in order to neutralize the internal acidity of the plant residues as much as possible, the crushed residues need to be sampled by batch unit before entering a mixing bin for detection of the acidity value, the sampling object is residual liquid extruded in dehydration processing, the input amount of the conventional alkali is determined by the detected acid content, and the input amount is controlled by matching with a flow valve.

In order to sufficiently disperse and dissolve the plant residue in the alcohol treatment solution for each batch; the adding amount of the alcohol treatment liquid is based on the basic standard of the residual raw materials, the temperature of the residual raw materials is kept between 75 and 85 ℃ when the residual raw materials are heated and stirred in a mixing bin, the duration is 6 to 8 minutes, the residual raw materials and the alkali-containing alcohol treatment liquid are subjected to neutralization and decomposition reaction at high temperature, sufficient time and conditions are provided for the neutralization, dispersion and decomposition of the plant residues, and finally the mixed alcohol-based fuel is obtained.

In order to prevent a few insoluble substances floating inside the mixed alcohol-based fuel from settling after the mixed alcohol-based fuel is stored for a long time and influence the flowability of insoluble substance residue fibers in the mixed alcohol-based fuel, the mixed alcohol-based fuel needs to be slowly stirred after being stored in a buffer bin and before needing to be conveyed to a boiler system through a pressurized pipeline.

The plant extraction residue and the alcohol treatment liquid are combined, and the plant extraction residue and the alcohol treatment liquid are heated and stirred, so that the plant residue can be effectively dispersed in the alcohol treatment liquid to form the mixed alcohol-based liquid fuel, and the treatment mode influences the combustion heat value of the alcohol-based fuel to a certain extent for a small amount of moisture contained in the plant residue, but does not influence the normal combustion of the alcohol-based fuel, and the combustion stability is easy to control.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement or the like made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (9)

1. A method of treating plant residues for fuel, comprising:

s1, sending the plant residues in the temporary storage bin into a crushing machine for crushing treatment to obtain residue crushed aggregates;

s2, conveying the residue crushed aggregates processed by the crusher to a screw extrusion dehydrator for dehydration through a heating type screw feeder while heating, so as to obtain residual liquid and residue stock with the moisture content not more than 10%, wherein the residual liquid is uniformly collected in a residual liquid collecting tank and stored for waiting for waste liquid treatment; preparing the residue for standby;

s3, feeding the prepared residue into a mixing bin, adding conventional alkali and alcohol treatment liquid, and simultaneously heating and stirring to neutralize and disperse the residue in the mixing bin; obtaining mixed alcohol-based fuel;

and S4, feeding the mixed alcohol-based fuel into a buffer bin, and finally feeding the mixed alcohol-based fuel to a combustion furnace through a pipeline pressurization system to serve as fuel.

2. The method of claim 1, wherein: in S2, two screw extrusion dewaterers are sequentially arranged from front to back, a feed inlet of a second screw extrusion dewaterer is positioned at the bottom end of a discharge outlet of the first screw extrusion dewaterer, the height difference is kept at 60-70 cm, and a steel bar blocking fork is further arranged in the second screw extrusion dewaterer.

3. The method of claim 1, wherein: in S2, the heating type spiral feeder adopts hot water as a heat conducting medium, and the hot water comes from a hot water system for recycling boiler heat.

4. The method of claim 1, wherein: and S2, heating the residue and crushed aggregates at 70-80 ℃.

5. The method of claim 1, wherein: in S3, the conventional alkali includes, but is not limited to, aqueous solution containing caustic soda, ammonia water or lime water and the like.

6. The method of claim 1, wherein: and S3, sampling the crushed residue materials in batch unit before entering a mixing bin to detect the acidity value, wherein the sampling object is residual liquid extruded in dehydration, the input amount of conventional alkali is determined by the detected acid content, and the input amount is controlled by matching with a flow valve.

7. The method of claim 1, wherein: in S3, the alcohol content in the alcohol treatment liquid is 75-80%, wherein the alcohol is liquid containing various simple alcohols such as methanol and ethanol or polyhydric alcohols or alcohol solid with a melting point lower than 90 ℃.

8. The method of claim 1, wherein: in S3, the addition amount of the alcohol treatment liquid is based on the basic standard of the residual stock, the temperature of the residual stock is kept at 75-85 ℃ when the residual stock is heated and stirred in a mixing bin, the duration is 6-8 minutes, and the residual stock and the alkali-containing alcohol treatment liquid are subjected to neutralization and decomposition reaction at high temperature to obtain the mixed alcohol-based fuel.

9. The method of claim 1, wherein: and S4, after the mixed alcohol-based fuel is stored in a buffer bin, the mixed alcohol-based fuel needs to be slowly stirred before being conveyed to a boiler system through a pressurized pipeline.

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