METHOD FOR PRODUCING A BIOFUEL BY STEAM CRACKING

Abstract

A method for producing a biofuel by continuous or discontinuous steam cracking of lignocellulosic biomass includes: —recording a digital model of the optimal steam cracking parameters as a function of the nature and the content of the contaminants; —introducing a biomass containing at least part of the contaminated biomass into the steam cracking reactor; —measuring at least once during the treatment the nature and content of the contaminants; and —controlling the adjustment of the steam cracking parameters as a function of the nature and the content of the measured contaminants and of the digital model.

Claims

1. A method for producing a biofuel by continuous or discontinuous steam cracking of lignocellulosic biomass, the method comprising: recording a digital model of optimal steam cracking parameters depending on the nature and the content of contaminants; introducing a biomass containing the contaminated biomass, at least in part, into the steam cracking reactor; measuring the nature and the content of the contaminants at least once during treatment of the biomass containing the contaminated biomass in the steam cracking reactor; and controlling adjustment of at least one parameter of the steam cracking depending on the nature and the content of the measured contaminants and on the digital model.

2. The method of claim 1, wherein the at least one parameter is selected from among the following group of parameters: severity factor, steam cracking pressure, steam cracking temperature, steam cracking duration, cessation of steam cracking, steam/solid ratio, filling rate of a steam cracking tank, speed of advance in a steam cracking tank, rate of compression at an inlet, rate of compression at an outlet of a discharge of the reactor with an orifice diameter, supply flow rate, humidity, or particle size.

3. The method of claim 1, wherein the biomass containing the contaminated biomass has a humidity of less than 27% at the time introducing the biomass into the steam cracking reactor.

4. The method of claim 1, wherein the measuring comprises taking a sample of the biomass entering the steam cracking reactor, and applying a physicochemical analysis to the sample to characterize and quantify the contaminants present.

5. The method of claim 1, wherein the measuring comprises taking a sample of waste gases or liquids in or at an outlet of the steam cracking reactor, and applying a physicochemical analysis to the sample to characterize and quantify the contaminants present.

6. The method of claim 1, wherein the measuring comprises taking a sample of a specimen of steam-cracked products in or at an outlet of the steam cracking reactor, in applying a physicochemical analysis to the sample to characterize and quantify the contaminants present.

7. The method of claim 1, wherein the measuring comprises taking a sample of a specimen of pellets, and applying a physicochemical analysis to the sample to characterize and quantify the contaminants present.

8. The method of claim 3, further comprising periodically recording and time stamping at least some results of the measuring of the nature and the content of the contaminants.

9. The method of claim 8, further comprising injecting the results into a blockchain.

10. The method of claim 8, further comprising injecting the results into a supervised learning system for producing the digital model.

11. The method of claim 1, wherein the digital model is determined by a series of chemical simulations.

12. A facility for producing a biofuel by steam cracking of contaminated lignocellulosic biomass, comprising: a continuous or discontinuous steam cracking reactor, at least one means for taking a sample of a specimen of steam-cracked products in or at an outlet of the steam cracking reactor, and a physicochemical analysis system configured to characterize and quantify contaminants present in a sample obtained from the steam cracking reactor, and at least one means for adjusting at least one of the following parameters: severity factor, steam cracking pressure, steam cracking temperature, steam cracking duration, cessation of steam cracking, steam/solid ratio, filling rate of the steam cracking reactor, speed of advance in the steam cracking reactor, rate of compression at an inlet, rate of compression at an outlet of a discharge of the reactor with an orifice diameter, supply flow rate, humidity, or particle size, wherein the adjustment means is controlled by a computer configured to implement the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The present disclosure will be more clearly understood upon reading the following detailed description, which refers to the accompanying drawings and relates to a non-limiting embodiment of the present disclosure, in which drawings:

[0065] FIG. 1 is a schematic view of a facility for discontinuous steam cracking, but the general principle applies for a continuous method.

DETAILED DESCRIPTION

[0066] Steam Cracking of Contaminated Biomass

[0067] In addition to the known effect of steam cracking for reducing the fibers into powder and homogenizing the biomasses, the effect of the steam treatment would make it possible to extract the extractable compounds made volatile by the partition of the minor or major molecules or elements in the vapor phase, or by chemical depolymerization reactions. Thus, heavy metals such as zinc can volatilize, plastics materials would be hydrolyzed and vaporized, chlorinated or nitrogenated compounds would be extracted, biological compounds would be inactivated.

[0068] The method according to the present disclosure does not clean the biomass, but modifies the concentrations in the solid fraction and enriches the gas fraction. The treatment of a volatile substance by conventional systems for treatment of waste gases, by washing, complexation or by combustion, is easier than on a solid fraction. Furthermore, the solid residue would see the reduction in concentration of some components—halogenated compounds, heavy metals, major elements (nitrogen, chlorine). These are elements widely pursued for the use of steam-cracked biomass in combustion (in the form of black pellets). However, the nature of the volatiles, their cleanup by combustion, and their possible toxicity, must be apprehended by rigorous analyses.

[0069] By acting on the treatment conditions (duration, temperature and thus severity), and by following the volatile emissions of compounds (chlorine, for example, but also heavy metals), as well as the tracers of fossil plastics polymers or of chemical treatment on the solid fraction, it is possible to orientate the partition of the molecules and to obtain a black pellet that contains fewer additives, allowing for uses that would have generally been limited.

[0070] Description of an Embodiment of a Facility

[0071] FIG. 1 is a schematic view of a facility for steam cracking or explosion of biomass. The facility for steam explosion includes an evaporator (100) that generates steam, and a reactor (200) that is subj ected to rapid decompression.

[0072] The facility comprises a steam cracking reactor (200) and a spark arrestor (300). The reactor (200) is filled with biomass via the valve (13). Following closure of the valve (13), the steam is introduced into the reactor via the charging valve (6). The reactor (200) is then allowed to reach the target temperature, before starting the time period at the desired temperature. Typically, approximately 20 seconds are required for reaching the desired temperature. At the end of the desired period, the valve (9) is opened to allow the explosive decompression. The steam-exploded material passes through the connection pipe and fills the spark arrestor (300).

[0073] A high-pressure pump (1) supplies the steam generator (100). Heating bands (2) ensure the thermostabilization of the various items of equipment.

[0074] The facility furthermore comprises pressure gauges and sensors (3) for measuring the pressure and the temperature in the steam generator (100), as well as a pressure gauge and sensor (4) for measuring the pressure and the temperature in the reactor (200). An isolating valve (5) controls the entry of the steam into the generator (100). A safety valve (7) limits the pressure in the steam generator (100). The reactor (200) also comprises a safety valve. The spark arrestor (300) is equipped with a pressure gauge (12). The supply of the reactor (200) is achieved by a supply chamber (14), which draws along a controlled volume of the biomass stored in a reserve (15).

[0075] The facility comprises one or more items of sampling equipment (50 to 54) for solid, liquid or gaseous specimens, for analyzing the content of contaminants. These data are processed by a programmable machine (16) that controls the parameters of the facility, depending on the result of the analyses and the parameters provided by the pressure and temperature sensors. The data are furthermore stored in a memory (17), which also contains the recording of the processing model determining the parameters to apply, depending on the result of the analyses.

[0076] This memory (17) is associated with a computer that applies supervised learning processing to the historical data stored in the memory (17), and that also controls the injection of the data into a blockchain.

[0077] Severity factor and control of the facility.

[0078] The control measures for the treatment of a contaminated biomass takes into account the optimal elimination conditions, in the reactor (200), of some of the contaminants.

[0079] The control measures of the parameters and of the operating point are thus selected not merely depending on the processes of destructuration of the lignocellulosic materials, but also on their effect on the evaporation or the destruction of some contaminants or the decontamination reactions.

[0080] For this purpose, a digital model of control measures is developed, suitable for each contaminant and for each contaminant combination, in order to have available a digital reference that makes it possible to automatically adapt the parameters, depending on the nature of the biomass entering the reactor (200).

[0081] The construction of this model can be carried out experimentally, performing a succession of treatments of various contaminated biomasses, having different control measures, in order to retain the control measures corresponding to the minimization of the contaminants still present in the pellets produced.

[0082] This model can also be drawn up by a supervised learning solution, from recorded historic data.

[0083] Finally, the model can be drawn up by simulation of chemical reactions relating to the main contaminants that may be present in some biomasses.

[0084] This model determines the control measures to be selected, for each class of contaminants.

[0085] During a new treatment, the physicochemical analyses provide the nature and the composition of the contaminants, and a computer automatically determines the control measures of the facility, depending on the result of the analyses, and on the recorded digital model.

[0086] The pellets thus produced all have the same calorific qualities, furthermore improving the sterility and biological safety of the pellets, despite being obtained from contaminated biomass, in particular, biological contaminants (fungi, bacteria, etc.).