阅读说明：本技术 一种利用再造梗丝废弃物制备生物炭基肥的方法 (Method for preparing biochar-based fertilizer by utilizing reconstituted cut stem waste ) 是由 刘琪 李炜 徐光忠 徐冬梅 陈晶波 张峥 马梦婕 朱莹 于 2021-03-09 设计创作，主要内容包括：本发明公开了一种利用再造梗丝废弃物制备生物炭基肥的方法,包括以下步骤：S1、收集再造梗丝生产过程中产生的废水,然后将收集到的废水进行蒸馏得固体废弃物；S2、将上述步骤得到的固体废弃物加入适量溶剂中,并向其中加入适量无机盐搅拌均匀得混合溶液；S3、对上述步骤制备的混合溶液进行湿法热解,使得溶液内的固体废弃物加热炭化得到生物炭基质,炭化完成后自然冷却,然后用超纯水与乙醇的混合溶液洗涤数次,干燥制得生物炭基肥。本发明提供的制备生物炭基肥的方法,以废弃物为原料,通过湿法热解技术制备生物炭基肥。该生物炭基肥可以有效保持土壤水分、增加微生物活性、锁住土壤中养分、促进植物生长、建立持久肥效。(The invention discloses a method for preparing a biochar-based fertilizer by using reconstituted cut stem waste, which comprises the following steps: s1, collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste; s2, adding the solid waste obtained in the step into a proper amount of solvent, adding a proper amount of inorganic salt into the solvent, and uniformly stirring to obtain a mixed solution; and S3, performing wet pyrolysis on the mixed solution prepared in the step, heating and carbonizing the solid waste in the solution to obtain a biochar substrate, naturally cooling the biochar substrate after carbonization is completed, washing the biochar substrate for a plurality of times by using the mixed solution of ultrapure water and ethanol, and drying the biochar substrate to obtain the biochar-based fertilizer. The method for preparing the biochar-based fertilizer provided by the invention takes waste as a raw material and prepares the biochar-based fertilizer by a wet pyrolysis technology. The biochar-based fertilizer can effectively keep soil moisture, increase microbial activity, lock nutrients in soil, promote plant growth and establish lasting fertilizer effect.)

1. A method for preparing a biochar-based fertilizer by using reconstituted cut stem waste is characterized by comprising the following steps:

s1, collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

s2, adding the solid waste obtained in the step into a proper amount of solvent, adding inorganic salt into the solvent, and uniformly stirring to obtain a mixed solution;

and S3, performing wet pyrolysis on the mixed solution prepared in the step, heating and carbonizing the solid waste in the solution to obtain a biochar substrate, naturally cooling the biochar substrate after carbonization is completed, washing the biochar substrate by using the mixed solution of ultrapure water and ethanol, and drying the biochar substrate to obtain the biochar-based fertilizer.

2. The method for preparing the biochar-based fertilizer by using the reconstituted cut stem waste according to claim 1, wherein the stirring time in the step S2 is 1-1.5 hours, and the stirring temperature is 20-25 ℃.

3. The method for preparing the biochar-based fertilizer by using the reconstituted cut rolled stem waste according to claim 1, wherein the solvent in the step S2 is phosphoric acid.

4. The method for preparing biochar-based fertilizer by using reconstituted cut stem waste according to claim 1, wherein the mass ratio of inorganic salt to solid waste in the step S2 is 0.01: 1.

5. the method for preparing the biochar-based fertilizer by using the reconstituted cut rolled stem waste according to claim 1, wherein the inorganic salt in the step S2 comprises one or more of copper sulfate, manganese sulfate and zinc sulfate.

6. The method for preparing the biochar-based fertilizer by using the reconstituted cut rolled stem waste as claimed in claim 1, wherein the temperature of the wet pyrolysis in the step S3 is 160-220 ℃.

7. The method for preparing the biochar-based fertilizer by using the reconstituted cut rolled stem waste according to claim 1, wherein the wet pyrolysis time in the step S3 is 2-6 hours.

8. The method for preparing the biochar-based fertilizer by using the reconstituted cut rolled stem waste according to claim 1, wherein the temperature rise rate of the wet pyrolysis in the step S3 is 10-20 ℃/h.

9. The method for preparing the biochar-based fertilizer by using the reconstituted cut stem waste according to claim 1, wherein the mass ratio of ethanol to ultrapure water in the step S3 is 1: 2.

10. The method for preparing the biochar-based fertilizer by using the reconstituted cut stem waste according to claim 1, wherein the biochar-based fertilizer is washed 3-5 times by a mixed solution of ultrapure water and ethanol in the step S3.

Technical Field

The invention relates to the field of biochar-based fertilizer preparation, in particular to a method for preparing biochar-based fertilizer by utilizing reconstituted cut stem waste.

Background

The carbon-based fertilizer is an ecological environment-friendly fertilizer prepared by adding organic matters or/and inorganic matters into biomass carbon serving as a matrix according to the characteristics of land in different areas, the growth characteristics of different crops and a scientific fertilization principle. The carbon-based fertilizer can increase the content of carbon-organic matters in soil, quickly reform the soil structure, balance salt and water, and create a soil environment beneficial to healthy growth of plants through quick curing, thereby increasing the soil fertility and promoting the growth of crops. The effect of the carbon-based fertilizer is mainly derived from the effect of biomass charcoal, which includes but is not limited to: 1. keeping the soil moisture; 2. increasing microbial activity; 3. locking nutrients in the soil; 4. promoting the growth of plants; 5. and (3) establishing a lasting fertilizer effect. Carbon-based fertilizers have begun to be widely distributed in the market, and the field test effect of the carbon-based fertilizers is verified by a plurality of growers, so that the carbon-based fertilizers have remarkable effects on improving the soil and improving the crop quality. At present, carbon-based fertilizer products on the market mainly comprise: biochar-based fertilizer and the like. The biochar-based fertilizer is prepared by mixing/compounding biochar matrix and inorganic fertilizer or organic fertilizer by different processes, and the special effect of the biochar matrix is determined by the unique structural characteristics of the biochar matrix. The biochar base fertilizer is formed by fusing the biochar matrix with organic nutrients, inorganic nutrients and beneficial microorganisms.

Researches find that the common problem in the tobacco growth process is that the potassium in the tobacco leaves is deficient, and the potassium is closely related to the appearance quality, the combustibility, the nicotine content and the like of the tobacco leaves. The biochar matrix prepared by the reconstituted cut stem waste has the characteristic of being rich in potassium.

Meanwhile, a large amount of wastewater is generated in the production process of the stem shreds, the wastewater is difficult to treat, and the traditional wastewater treatment method is that the wastewater is directly discharged outdoors after being purified, so that a large amount of manpower and material resources are consumed.

And because the essence of the process for preparing the biochar by the traditional method is the process of carrying out high-temperature pyrolysis on organic matters, organic pollutants such as polycyclic aromatic hydrocarbon and the like are inevitably generated in the process. Researches show that both combustion residues and gas contain polycyclic aromatic hydrocarbons, the discharge parameters of the polycyclic aromatic hydrocarbons are respectively 5.26, 1.37 and 1.74mg/kg, which shows that a large amount of polycyclic aromatic hydrocarbons can be generated in the combustion of straws, the polycyclic aromatic hydrocarbons contained in the biochar can easily cause the content of the polycyclic aromatic hydrocarbons in the soil to reach the degree of moderate or severe pollution under the condition of high application amount, in addition, organic pollutants such as antibiotics and phthalic acid esters are often present in the fertilizer, the pollutants are often low in content and difficult to degrade in the environment, belong to persistent organic pollutants, and can bring potential safety hazards to agricultural products after being applied to the soil.

Disclosure of Invention

In order to solve the problems, the invention provides a method for preparing a biochar-based fertilizer by using reconstituted cut stem waste, which is to primarily distill waste water generated in the production process of the reconstituted cut stem to obtain a large amount of solid waste. The biochar-based fertilizer is prepared from wastes through a wet pyrolysis technology. The biochar-based fertilizer can effectively keep soil moisture, increase microbial activity, lock nutrients in soil, promote plant growth and establish lasting fertilizer effect.

In order to achieve the purpose, the technical scheme provided by the invention is as follows: a method for preparing a biochar-based fertilizer by using reconstituted cut stem waste is characterized by comprising the following steps:

s1, collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

s2, adding the solid waste obtained in the step into a proper amount of solvent, adding a proper amount of inorganic salt into the solvent, and uniformly stirring to obtain a mixed solution;

and S3, performing wet pyrolysis on the mixed solution prepared in the step, heating and carbonizing the solid waste in the solution to obtain a biochar substrate, naturally cooling the biochar substrate after carbonization is completed, washing the biochar substrate by using the mixed solution of ultrapure water and ethanol, and drying the biochar substrate to obtain the biochar-based fertilizer.

Further, the stirring time in the step S2 is 1-1.5h, and the stirring temperature is 20-25 ℃.

Further, the solvent in step S2 is phosphoric acid.

Further, in the step S2, the mass ratio of the inorganic salt to the solid waste is 0.01: 1.

further, the inorganic salt in step S2 includes one or more of copper sulfate, manganese sulfate, and zinc sulfate.

Further, the temperature of the wet pyrolysis in the step S3 is 160-220 ℃.

Further, the wet pyrolysis time in the step S3 is 2-6 h.

Further, the temperature rising rate of the wet pyrolysis in the step S3 is 10-20 ℃/h.

Further, the mass ratio of the ethanol to the ultrapure water in the step S3 is 1: 2.

Further, the step S3 is performed by washing with a mixed solution of ultrapure water and ethanol for 3 to 5 times.

In the preparation method, the collected wastewater is distilled to obtain solid waste, and the solid waste is detected to have the characteristic of being rich in potassium, mainly comprising lignin, hemicellulose, cellulose, polysaccharide and impurities (dust, hair and the like). The tobacco leaf also contains a plurality of beneficial elements, such as amino acids, proteins, nicotine and other compounds, which can provide mineral elements, nutrient components, trace elements and the like required by the growth of tobacco. Therefore, the biochar matrix is prepared by the aid of the reconstituted cut stem waste, so that the problem of treatment of traditional wastewater can be effectively solved, the cut stem waste can be recycled, and the development concept of environmental protection is met.

In the preparation method, the wet pyrolysis is to catalyze the decomposition and bond breaking of lignin and cellulose in the solid waste by using a solvent (phosphoric acid) medium, so that the solid waste can be carbonized at the temperature of about 200 ℃ to prepare the biochar substrate, and compared with the traditional preparation method, the preparation method greatly reduces the reaction energy consumption and simplifies the production process. Meanwhile, the low-temperature preparation can also improve the yield of the biochar substrate.

The wet pyrolysis technology is carried out under the condition of liquid phase reaction, and drying treatment and high-pressure and high-temperature equipment are not needed, so that the preparation cost of the wet pyrolysis biochar-based fertilizer is far lower than that of the traditional biochar-based fertilizer, and meanwhile, environmental pollution and potential safety hazards caused by high-temperature pyrolysis can be avoided.

The invention has the beneficial effects that:

1. the method for preparing the biochar-based fertilizer by using the reconstituted cut stem waste provided by the invention can keep soil moisture, increase microbial activity, lock nutrients in soil, promote plant growth and establish lasting fertilizer effect.

2. The invention provides a method for preparing a biochar-based fertilizer by utilizing reconstituted cut stem waste, wherein wet pyrolysis is to catalyze the decomposition and bond breaking of lignin and cellulose in solid waste by utilizing a solvent medium, so that the solid waste can be carbonized at the temperature of about 200 ℃ to prepare a biochar matrix, and compared with the traditional preparation method, the method greatly reduces the reaction energy consumption and simplifies the production process. Meanwhile, the low-temperature preparation can also improve the yield of the biochar substrate. Meanwhile, environmental pollution and potential safety hazards caused by high-temperature pyrolysis can be avoided.

3. According to the method for preparing the biochar-based fertilizer by using the reconstituted cut stem waste, provided by the invention, the biochar-based fertilizer is prepared by taking the wastewater generated in the production process of the reconstituted cut stems as a raw material, so that the method is greatly helpful for purification treatment of the wastewater and has important significance for environmental protection. The waste is recycled, so that the pollution to the environment can be reduced, the preparation cost can be reduced, and the concept of environment-friendly development is met.

Drawings

Fig. 1 is a flow chart of a method for preparing a biochar-based fertilizer by using reconstituted cut stem waste in an embodiment of the invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the following will describe the specific embodiments of the present invention with reference to the accompanying drawings.

It is obvious that the drawings in the following description are only some examples of the invention, and it is obvious to a person skilled in the art that other drawings and other embodiments can be obtained from these drawings without inventive effort, and the invention is not limited to this example.

For example, in the prior art, the process of reconstructing the cut stems is specifically as follows:

1, preparing blank cut stems: sequentially carrying out shredding, extraction, solid-liquid separation and drying on the pretreated tobacco stems to obtain blank cut stems with uniform quality;

2, sequentially extracting, carrying out solid-liquid separation and concentrating the extracting solution on the mixed tobacco raw material to prepare a backfill stock solution;

3, adding a functional essence supplementing liquid into the backfill stock solution to prepare a backfill solution;

and 4, uniformly spraying the backfill liquid on the blank cut stems, fully stirring and mixing, and drying to obtain a mixed type reproduced cut stem finished product.

Collecting a large amount of wastewater generated in the steps 1 and 4, distilling the collected wastewater to obtain solid waste, and detecting that the solid waste has the characteristic of being rich in potassium, mainly comprising lignin, hemicellulose, cellulose, polysaccharide and impurities (dust, hair and the like). The tobacco leaf also contains a plurality of beneficial elements, such as amino acids, proteins, nicotine and other compounds, which can provide mineral elements, nutrient components, trace elements and the like required by the growth of tobacco. Therefore, the wastewater can be used as a raw material to prepare the biochar-based fertilizer.

The specific embodiment of the invention is as follows:

example 1

Collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

adding 50g of solid waste obtained by distillation into 1L of phosphoric acid to completely dissolve the solid waste, adding 0.005g of inorganic salt into the solid waste, and uniformly stirring to obtain a mixed solution, wherein the stirring time is 1h, the stirring temperature is 25 ℃, and the inorganic salt is specifically a mixture of copper sulfate 1: manganese sulfate 1: a mixture of zinc sulphate 2;

and (2) carrying out wet pyrolysis on the mixed solution prepared in the step, wherein the temperature of the wet pyrolysis is 160 ℃, the time is 6 hours, the heating rate is 10 ℃/h, so that solid waste in the solution is heated and carbonized to obtain a biochar substrate, the biochar substrate is naturally cooled after carbonization is finished, then the biochar substrate is washed for 3 times by using the mixed solution of ultrapure water and ethanol, and the biochar substrate fertilizer is prepared by drying, wherein the mass ratio of ethanol to ultrapure water is 1: 2.

Example 2

Collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

adding 50g of solid waste obtained by distillation into 1L of phosphoric acid to completely dissolve the solid waste, adding 0.005g of inorganic salt into the solid waste, and uniformly stirring to obtain a mixed solution, wherein the stirring time is 1h, the stirring temperature is 25 ℃, and the inorganic salt is specifically a mixture of copper sulfate 1: manganese sulfate 1: a mixture of zinc sulphate 2;

and (2) carrying out wet pyrolysis on the mixed solution prepared in the step, wherein the temperature of the wet pyrolysis is 180 ℃, the time is 4 hours, the heating rate is 15 ℃/h, so that solid waste in the solution is heated and carbonized to obtain a biochar substrate, the biochar substrate is naturally cooled after carbonization is finished, then the biochar substrate is washed for 3 times by using the mixed solution of ultrapure water and ethanol, and the biochar substrate fertilizer is prepared by drying, wherein the mass ratio of ethanol to ultrapure water is 1: 2.

Example 3

Collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

adding 50g of solid waste obtained by distillation into 1L of phosphoric acid to completely dissolve the solid waste, adding 0.005g of inorganic salt into the solid waste, and uniformly stirring to obtain a mixed solution, wherein the stirring time is 1h, the stirring temperature is 25 ℃, and the inorganic salt is specifically a mixture of copper sulfate 1: manganese sulfate 1: a mixture of zinc sulphate 2;

and (2) carrying out wet pyrolysis on the mixed solution prepared in the step, wherein the temperature of the wet pyrolysis is 200 ℃, the time is 2 hours, the heating rate is 20 ℃/h, so that solid waste in the solution is heated and carbonized to obtain a biochar substrate, the biochar substrate is naturally cooled after carbonization is finished, then the biochar substrate is washed for 3 times by using the mixed solution of ultrapure water and ethanol, and the biochar substrate fertilizer is prepared by drying, wherein the mass ratio of ethanol to ultrapure water is 1: 2.

Example 4

Collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

adding 50g of solid waste obtained by distillation into 1L of phosphoric acid to completely dissolve the solid waste, adding 0.005g of inorganic salt into the solid waste, and uniformly stirring to obtain a mixed solution, wherein the stirring time is 1h, the stirring temperature is 25 ℃, and the inorganic salt is specifically a mixture of copper sulfate 1: manganese sulfate 1: a mixture of zinc sulphate 2;

and (2) carrying out wet pyrolysis on the mixed solution prepared in the step, wherein the temperature of the wet pyrolysis is 220 ℃, the time is 2 hours, the heating rate is 20 ℃/h, so that solid waste in the solution is heated and carbonized to obtain a biochar substrate, the biochar substrate is naturally cooled after carbonization is finished, then the biochar substrate is washed for 3 times by using the mixed solution of ultrapure water and ethanol, and the biochar substrate fertilizer is prepared by drying, wherein the mass ratio of ethanol to ultrapure water is 1: 2.

The biochar-based fertilizers prepared in examples 1-4 were subjected to component detection, as shown in Table 1

	Example 1	Example 2	Example 3	Example 4
					Total nutrient (N + P)2O5+K2O) mass fraction%	25	27	29	31
Water content (H)2O) mass fraction%	4.0	3.8	3.6	3.4
					Mass fraction of trace elements%	0.007	0.007	0.008	0.009

TABLE 1-examples 1 to 4 measurement results of biochar-based fertilizer content

Example 5

Collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

adding 50g of solid waste obtained by distillation into 1L of phosphoric acid to completely dissolve the solid waste, adding 0.005g of inorganic salt into the solid waste, and uniformly stirring to obtain a mixed solution, wherein the stirring time is 1.5h, the stirring temperature is 20 ℃, and the inorganic salt is specifically a copper sulfate 1: manganese sulfate 1: a mixture of zinc sulphate 2;

and (2) carrying out wet pyrolysis on the mixed solution prepared in the step, wherein the temperature of the wet pyrolysis is 160 ℃, the time is 6 hours, the heating rate is 10 ℃/h, so that solid waste in the solution is heated and carbonized to obtain a biochar substrate, the biochar substrate is naturally cooled after carbonization is finished, then the biochar substrate is washed for 3 times by using the mixed solution of ultrapure water and ethanol, and the biochar substrate fertilizer is prepared by drying, wherein the mass ratio of ethanol to ultrapure water is 1: 2.

Example 6

Collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

adding 50g of solid waste obtained by distillation into 1L of phosphoric acid to completely dissolve the solid waste, adding 0.005g of inorganic salt into the solid waste, and uniformly stirring to obtain a mixed solution, wherein the stirring time is 1.5h, the stirring temperature is 20 ℃, and the inorganic salt is specifically a copper sulfate 1: manganese sulfate 1: a mixture of zinc sulphate 2;

and (2) carrying out wet pyrolysis on the mixed solution prepared in the step, wherein the temperature of the wet pyrolysis is 180 ℃, the time is 4 hours, the heating rate is 15 ℃/h, so that solid waste in the solution is heated and carbonized to obtain a biochar substrate, the biochar substrate is naturally cooled after carbonization is finished, then the biochar substrate is washed for 3 times by using the mixed solution of ultrapure water and ethanol, and the biochar substrate fertilizer is prepared by drying, wherein the mass ratio of ethanol to ultrapure water is 1: 2.

Example 7

Collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

adding 50g of solid waste obtained by distillation into 1L of phosphoric acid to completely dissolve the solid waste, adding 0.005g of inorganic salt into the solid waste, and uniformly stirring to obtain a mixed solution, wherein the stirring time is 1.5h, the stirring temperature is 20 ℃, and the inorganic salt is specifically a copper sulfate 1: manganese sulfate 1: a mixture of zinc sulphate 2;

and (2) carrying out wet pyrolysis on the mixed solution prepared in the step, wherein the temperature of the wet pyrolysis is 200 ℃, the time is 2 hours, the heating rate is 20 ℃/h, so that solid waste in the solution is heated and carbonized to obtain a biochar substrate, the biochar substrate is naturally cooled after carbonization is finished, then the biochar substrate is washed for 3 times by using the mixed solution of ultrapure water and ethanol, and the biochar substrate fertilizer is prepared by drying, wherein the mass ratio of ethanol to ultrapure water is 1: 2.

Example 8

Collecting waste water generated in the production process of the reconstituted cut stems, and distilling the collected waste water to obtain solid waste;

adding 50g of solid waste obtained by distillation into 1L of phosphoric acid to completely dissolve the solid waste, adding 0.005g of inorganic salt into the solid waste, and uniformly stirring to obtain a mixed solution, wherein the stirring time is 1.5h, the stirring temperature is 20 ℃, and the inorganic salt is specifically a copper sulfate 1: manganese sulfate 1: a mixture of zinc sulphate 2;

and (2) carrying out wet pyrolysis on the mixed solution prepared in the step, wherein the temperature of the wet pyrolysis is 220 ℃, the time is 2 hours, the heating rate is 20 ℃/h, so that solid waste in the solution is heated and carbonized to obtain a biochar substrate, the biochar substrate is naturally cooled after carbonization is finished, then the biochar substrate is washed for 3 times by using the mixed solution of ultrapure water and ethanol, and the biochar substrate fertilizer is prepared by drying, wherein the mass ratio of ethanol to ultrapure water is 1: 2.

The biochar-based fertilizers prepared in examples 5 to 8 were subjected to component detection, as shown in Table 2

	Example 5	Example 6	Example 7	Example 8
					Total nutrient (N + P)2O5+K2O) mass fraction%	25	27	29	31
Water content (H)2O) mass fraction%	4.0	3.8	3.6	3.4
					Mass fraction of trace elements%	0.005	0.006	0.006	0.007

TABLE 2-measurement results of biochar-based fertilizer content in examples 5 to 8

As can be seen from tables 1 and 2, under different wet pyrolysis conditions in inventive examples 1-8, corresponding biochar-based fertilizers can be prepared, and the prepared biochar-based fertilizers meet the standards in the industry. The solvent phosphoric acid is used as a medium to catalyze the decomposition and bond breaking of lignin and cellulose, so that the biochar matrix can be prepared by carbonizing the lignin and cellulose at the temperature lower than 200 ℃. The addition of the copper sulfate, the manganese sulfate and the zinc sulfate can introduce trace elements such as copper, manganese, zinc and the like into the biochar-based fertilizer, so that the nutritional value of the biochar-based fertilizer is further improved.

The above-described aspects may be implemented individually or in various combinations, and such variations are within the scope of the present invention.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the specific embodiments of the invention be limited to these descriptions. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.