JP5616764B2 - Internal heat exchange type distillation equipment - Google Patents

Description

  The present invention relates to an internal heat exchange distillation apparatus.

  Conventionally, an internal heat exchange distillation apparatus developed as a highly efficient distillation column in the petrochemical industry is known (see, for example, Patent Document 1).

  The internal heat exchange distillation apparatus includes a first distillation column and a second distillation column disposed inside the first distillation column, and the second distillation column is an interior of the first distillation column. The inside and outside are separated from each other. The internal heat exchange distillation apparatus moves the heat of the second distillation column to the first distillation column, for example, with the side wall of the second distillation column as the heat transfer surface.

  The internal heat exchange distillation apparatus is used in the petrochemical industry, for example, for fractional distillation of benzene and toluene. At this time, according to the internal heat exchange type distillation apparatus, the heat transferred from the second distillation column to the first distillation column reduces the heating and cooling work, thereby reducing the thermal energy required for distillation. can do.

Japanese Patent No. 2694425

  However, in the internal heat exchange distillation apparatus, depending on the raw material solution to be distilled, a deposited component adheres and accumulates on the side wall of the second distillation column and acts as a heat insulating material, and the first distillation from the second distillation column. There is an inconvenience that heat transfer to the tower may be hindered.

  Therefore, the present invention provides an internal heat exchange distillation apparatus that eliminates such inconvenience and can be smoothly operated without hindering heat transfer from the second distillation column to the first distillation column. For the purpose.

In order to achieve this object, an internal heat exchange distillation apparatus of the present invention includes a first distillation column and a second distillation which is disposed inside the first distillation column and the inside and the outside are isolated from each other. A tower, a first supply conduit for supplying a fermentation solution obtained by fermenting a saccharified solution obtained by saccharifying lignocellulosic biomass as a raw material solution to the first distillation tower, and a top of the first distillation tower A second supply conduit for taking out the obtained first gas and supplying it to the second distillation column, and a second distillation column provided in the middle of the second supply conduit in the second distillation column than in the first distillation column. Heat exchange for preheating the fermentation solution by exchanging heat between the fermentation solution and the column bottom liquid, a pressure difference generating means for increasing the pressure, a first extraction conduit for extracting the column bottom liquid of the first distillation column Heating means for heating the first distillation column by means of a vessel and a steam pipe for supplying steam directly into the first distillation column; A second distillation pipe for taking out the second gas obtained at the top of the tower, and a condenser provided in the middle of the second extraction pipe for cooling and liquefying the second gas. In an internal heat exchange type distillation apparatus that moves the heat of the second distillation column to the first distillation column with the side wall of the column as the heat transfer surface, phosphoric acid contained in the fermentation solution is added to the side wall of the second distillation column. An adhesion / deposition prevention layer for preventing a deposition component consisting of a mixture of a salt, a silicate and a protein from being deposited and adhering to and depositing, comprising 79 to 90% by mass of Ni, 7 to The Ni—P alloy containing 9.5% by mass of P contains a fluorine resin in the range of 12 to 34% by mass and has a thickness of 5 μm or less.

  In the internal heat exchange type distillation apparatus of the present invention, first, the raw material solution supplied from the first supply conduit to the first distillation column is heated and distilled by the heating means, whereby the first distillation column is obtained. The first gas containing the low boiling point component in the raw material solution is obtained at the top of the column. The first gas is supplied to the second distillation column via the second supply conduit. At this time, the pressure difference generating means causes the second distillation column to be introduced from the first distillation column. Also, the temperature in the second distillation column rises due to the high pressure.

  In the internal heat exchange distillation apparatus of the present invention, the pressure difference generating means sets the first distillation column to atmospheric pressure, pressurizes the first gas, and sets the second distillation column to atmospheric pressure or higher. It is good also as a pressurization state. Further, the pressure difference generating means may depressurize the inside of the first distillation column so that the inside of the first distillation column is in a reduced pressure state equal to or lower than atmospheric pressure, and the inside of the second distillation column may be set to atmospheric pressure.

  As a result, the first gas is further distilled in the second distillation column, and a second gas containing the low-boiling component having a higher concentration than the first gas is obtained at the top of the second distillation column. . The second gas is taken out from the second take-out conduit, cooled by the condenser, and liquefied, whereby the low boiling point liquid can be obtained.

  In the internal heat exchange type distillation apparatus of the present invention, the temperature in the second distillation column rises as the pressure difference generating means makes the pressure in the second distillation column higher than that in the first distillation column. However, the temperature is higher than the temperature in the first distillation column. As a result, the heat of the second distillation column moves to the first distillation column using the side wall of the second distillation column as the heat transfer surface. Accordingly, the first distillation column is further heated, and the temperature of the second distillation column is lowered. Therefore, the heating and cooling work can be reduced, and the heat energy required for distillation can be reduced.

  However, when the raw material solution to be distilled contains a precipitation component, the precipitation component deposits and deposits on the side wall of the second distillation tower, and the precipitation component acts as a heat insulating material. There is a concern that heat transfer to the first distillation column is hindered.

  In view of this, the internal heat exchange distillation apparatus of the present invention includes an adhesion deposition preventing layer that prevents the deposition components contained in the raw material solution from being deposited and deposited on the side wall of the second distillation column. . As a result, according to the internal heat exchange type distillation apparatus of the present invention, it is possible to prevent the precipitation component from being deposited and deposited on the side wall of the second distillation column and to operate smoothly.

Internal heat exchanging type distillation apparatus of the present invention, prior Symbol raw material solution, when it is fermented solution fermented saccharification solution obtained by saccharifying lignocellulosic biomass, Ru physician use in distillation of the fermented solution . At this time, the precipitation component contained in the fermentation solution is a mixture of phosphate, silicate and protein.

In a heat integrated distillation apparatus of the present invention, the adhesion deposition preventing layer, Ni-P alloy including a 12-34 wt% of the fluororesin in. The adhesion deposition preventing layer can ensure the thermal conductivity of the side wall of the second distillation tower by the Ni-P alloy serving as a matrix, and is contained in the fermentation solution by containing the fluororesin in the range. It is possible to prevent the deposited components from being deposited. Moreover, the said adhesion deposition prevention layer acts especially effectively when the said precipitation component is a mixture of protein and an inorganic compound.

The fluorine resin contained in the deposited deposition preventing layer, with respect to the whole Ni-P alloy, when it is less than 12% by weight, the precipitation of the mixture of the protein and inorganic compounds that can not be prevent. Moreover, when the fluororesin contained in the adhesion deposition preventing layer exceeds 34 % by mass with respect to the entire Ni-P alloy, the heat insulating property of the adhesion deposition preventing layer becomes excessive, and the second distillation column Ru lowers the thermal conductivity of the side walls.

  In the internal heat exchange distillation apparatus of the present invention, it is preferable that the adhesion deposition preventing layer is formed by electroless plating. The adhesion deposition preventing layer can be formed by electroless plating regardless of the shape and size of the side wall of the second distillation column.

The system block diagram which shows the structure of the ethanol manufacturing apparatus using the internal heat exchange distillation apparatus of this invention. The chart of the Fourier-transform infrared spectroscopy spectrum which shows the component analysis example of a fermentation solution.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

  The internal heat exchange distillation apparatus of the present embodiment is used in an ethanol production apparatus for producing ethanol from lignocellulosic biomass such as rice straw as a substrate.

  As shown in FIG. 1, an ethanol production apparatus 1 that produces ethanol from lignocellulosic biomass includes a pretreatment apparatus 2, a saccharification treatment apparatus 3, a fermentation treatment apparatus 4, and an internal heat exchange distillation apparatus 5.

  The pretreatment device 2 includes a raw material supply device 21, an ammonia water supply device 22, a stirring tank 23, a storage tank 24, and a transfer conduit 25. The raw material supply device 21 supplies rice straw as a raw material substrate to the stirring tank 23, and the ammonia water supply device 22 supplies ammonia water to the stirring tank 23.

  The agitation tank 23 agitates and mixes the substrate and the aqueous ammonia, and supplies the obtained substrate mixture to the storage tank 24. While the substrate mixture is stored for a predetermined time, the storage tank 24 dissociates lignin from the substrate without heating or swells the substrate to obtain a pre-saccharification product.

  The lignocellulosic biomass has a structure in which lignin is firmly bound to cellulose or hemicellulose. Therefore, cellulose or hemicellulose can be saccharified by using the substrate as a pre-saccharification product by the treatment.

  In addition, in this application, dissociation means cut | disconnecting at least one part coupling | bonding among the binding sites of the lignin couple | bonded with the cellulose or hemicellulose of lignocellulosic biomass. Swelling means that voids are generated in cellulose or hemicellulose constituting crystalline cellulose by the intrusion of liquid, or voids are generated inside cellulose fibers to expand.

  The saccharification pretreatment product is taken out by a transfer conduit 25 connected to the bottom of the storage tank 24, and ammonia is separated by a solid-liquid separation device 26 provided in the middle of the transfer conduit 25. Is sent to the saccharification treatment apparatus 3. The solid-liquid separator 26 includes a recovery conduit 27 that recovers the separated ammonia as aqueous ammonia. The recovery conduit 27 is connected to the ammonia water supply device 22.

  The saccharification treatment apparatus 3 includes a saccharification treatment tank 31, a transfer conduit 25 is connected to the upper portion of the saccharification treatment tank 31, and a saccharification enzyme supply device 32 is provided. The ammonia supplied from the transfer conduit 25 A saccharification enzyme is supplied to the separated saccharification pretreatment product from the saccharification enzyme supply device 32 to perform saccharification treatment to obtain a saccharification solution.

  A transfer conduit 33 for transferring the saccharified solution obtained in the saccharification treatment tank 31 to the fermentation treatment apparatus 4 is connected to the bottom of the saccharification treatment tank 31. In the middle of the transfer conduit 33, a solid-liquid separator 34 is provided to separate and remove the rice straw residue and the like contained in the saccharified solution.

  The fermentation treatment apparatus 4 includes a fermentation treatment tank 41, a transfer conduit 33 is connected to the upper portion of the fermentation treatment tank 41, and a fungus body supply device 42 is provided, and the saccharification supplied from the transfer conduit 33 is performed. Fermented bacteria or yeast is supplied to the solution from the cell supply device 42 and fermented to obtain a fermentation solution. A transfer conduit 43 for transferring the fermentation solution obtained in the fermentation treatment tank 41 to the internal heat exchange distillation apparatus 5 is connected to the bottom of the fermentation treatment tank 41.

  The internal heat exchange distillation apparatus 5 of the present embodiment uses the fermentation solution supplied from the transfer conduit 43 as a raw material solution. The internal heat exchange distillation apparatus 5 includes a first distillation column 51 in which a second distillation column 52 is disposed. Inside the first distillation column 51, the inside and outside of the second distillation column 52, Are provided with a single distillation column 53 having a structure isolated from each other. The first distillation column 51 has a transfer conduit 43 connected to the upper part of the portion that is outside the second distillation column 52, takes out the first gas obtained at the top of the column, The gas supply conduit 54 for supplying the distillation column 52 is provided.

  The gas supply conduit 54 is provided with a dry vacuum pump 55 that depressurizes the inside of the first distillation column 51 in the middle, and is connected to the bottom of the second distillation column 52 on the downstream side of the dry vacuum pump 55. The first distillation column 51 includes a first extraction conduit 56 for extracting the column bottom liquid from the bottom of the portion that is outside the second distillation column 52. A heat exchanger 57 is provided in the middle of the first extraction conduit 56 to exchange heat between the fermentation solution supplied from the transfer conduit 43 and the bottom liquid and to preheat the fermentation solution.

  In addition, a steam pipe 58 that heats the first distillation column 51 by supplying steam directly into the first distillation column 51 is provided at the bottom of the first distillation column 51. In the internal heat exchange distillation apparatus 5, the heat exchanger 57 and the steam pipe 58 constitute a heating means for heating the first distillation column 51.

  On the other hand, the top of the second distillation column 52 is provided with a second extraction conduit 59 for taking out the second gas obtained at the top of the second distillation column 52, via a condenser 60. Ethanol as a product is taken out. In addition, the condenser 60 includes a reflux conduit 61 that refluxes the remaining liquid into the second distillation column 52.

The first distillation column 51 and the second distillation column 52 are formed of, for example, a stainless steel plate, and the second distillation column 52 is illustrated on the surface facing the inside of the first distillation column 51 on the outside thereof. It has a non-adhesive deposition prevention layer. The adhesion deposition preventing layer includes a fluororesin in a range of 12 to 34 % by mass in a Ni-P alloy containing 79 to 90% by mass of Ni and 7 to 9.5% by mass of P, and is 5 μm or less. With a thickness of.

  The adhesion deposition preventing layer may be formed, for example, by applying a predetermined electroless plating solution to a surface facing the inside of the first distillation column 51 outside the second distillation column 52 and performing electroless plating. it can. According to the electroless plating, unlike the electrolytic plating, it is not necessary to produce an electrode, and therefore, the adhesion deposition preventing layer can be formed easily and at a low cost regardless of the shape and size of the second distillation column 52. Can do.

Examples of the electroless plating solution include a Ni-P electroless plating solution, a fluororesin (for example, polytetrafluoroethylene) having an average particle size of 0.3 to 0.5 μm, a nonionic surfactant and a cationic surfactant. A material dispersed by an agent (manufactured by Nippon Kanisen Co., Ltd., trade name: Kaniflon) can be used .

  The electroless plating can be performed by immersing the second distillation column 52 in the electroless plating solution heated to a temperature in the range of 90 to 95 ° C. for a predetermined time.

  Next, the operation of the ethanol production apparatus 1 will be described.

  In the ethanol production apparatus 1, first, rice straw as a substrate supplied from the raw material supply apparatus 21 and ammonia water supplied from the ammonia water supply apparatus 22 are stirred in the stirring tank 23 to obtain a substrate mixture. The obtained substrate mixture is supplied to a storage tank 24 connected directly below the stirring tank 23, and stored in the storage tank 24 for a predetermined time, thereby dissociating lignin from the rice straw without heating, Alternatively, a pre-saccharification product is obtained by swelling the rice straw.

  Since the pre-saccharification product contains aqueous ammonia, ammonia is separated by the solid-liquid separation device 26 provided in the middle of the transfer conduit 25 while being transferred to the saccharification treatment tank 31 by the transfer conduit 25. . As a result, the ammonia separation saccharification pretreatment product is transferred to the saccharification treatment tank 31. On the other hand, the ammonia separated by the solid-liquid separator 26 is recovered as ammonia water by the recovery conduit 27 and is returned to the ammonia water supply device 22.

  In the saccharification treatment tank 31, the saccharification enzyme supplied from the saccharification enzyme supply device 32 is mixed with the ammonia separation saccharification pre-treatment product supplied via the transfer conduit 25, and held for a predetermined time. As a result, a saccharified solution obtained by saccharifying cellulose, hemicellulose and the like contained in rice straw as the substrate is obtained.

  The saccharification solution is taken out by a transfer conduit 33 connected to the bottom of the saccharification treatment tank 31, and the rice straw residue and the like are separated and removed by a solid-liquid separation device 34 provided in the middle of the transfer conduit 33. Then, it is transferred to the fermentation treatment tank 41.

  In the fermentation treatment tank 41, the fermented bacteria or yeast supplied from the microbial cell supply device 42 is mixed with the saccharified solution supplied via the transfer conduit 33 and held for a predetermined time. As a result, the sugar contained in the saccharified solution is ethanol-fermented with the fermenting bacteria or yeast, and a fermentation solution containing ethanol is obtained.

  The fermentation solution is taken out by a transfer conduit 43 connected to the bottom of the fermentation treatment tank 41 and transferred to the internal heat exchange distillation apparatus 5.

  In the internal heat exchange distillation apparatus 5, first, the fermentation solution supplied from the transfer conduit 43 to the first distillation column 51 is heat-exchanged with the column bottom liquid of the first distillation column 51 by the heat exchanger 57. It is further preheated and further heated by steam supplied from the steam pipe 58 to the first distillation column 51. As a result, the fermentation solution is distilled, and a first gas containing ethanol at a higher concentration than the fermentation solution is obtained as a low boiling point component at the top of the first distillation column 51.

  The first gas is supplied to the second distillation column 52 via the gas supply conduit 54 and the dry vacuum pump 55. At this time, the inside of the first distillation column 51 is depressurized by the dry vacuum pump 55. Therefore, while the inside of the first distillation column 51 is in a depressurized state below atmospheric pressure, the inside of the second distillation column 52 is at atmospheric pressure, and the temperature in the second distillation column 52 is higher than that in the first distillation column 51. Becomes hotter.

  As a result, the first gas is further distilled in the second distillation column 52, and a second gas containing a higher concentration of ethanol is obtained at the top of the second distillation column 52. The second gas is taken out by the second take-out conduit 59, cooled by the condenser 60 and liquefied, so that an ethanol solution containing ethanol having a higher concentration than the fermentation solution can be obtained as a product. The remaining liquid in the condenser 60 is refluxed into the second distillation column 52 through the reflux conduit 61.

  Here, in the internal heat exchange type distillation apparatus 5, the temperature in the second distillation column 52 is higher than the temperature in the first distillation column 51, so that heat is transferred through the side wall of the second distillation column 52. As a surface, the heat of the second distillation column 52 moves to the first distillation column 51. As a result of the heat transfer, the first distillation column 51 is further heated and the temperature of the second distillation column 52 is lowered, so that the work of heating and cooling can be reduced and the thermal energy required for distillation is reduced. can do.

  By the way, the fermentation solution supplied from the transfer conduit 43 to the first distillation column 51 contains proteins and inorganic compounds.

FIG. 2 shows a Fourier transform infrared spectrum of the fermentation solution. From FIG. 2, it is recognized that the fermentation solution contains phosphate, silicate (1200 to 900 cm ⁻¹ , 700 to 500 cm ⁻¹ ), and protein (1625, 1537 cm ⁻¹ , amide bond). Therefore, the precipitate is considered to be a complex of phosphate, silicate and protein.

  The protein is an enzyme used for the saccharification, a fermenting bacterium used for the fermentation, or a component derived from a cell of the enzyme, the silicate is a component of rice straw itself, and the phosphate is the fermentation bacterium or enzyme. It is considered to be a component used for the culture of Therefore, when the mixture of the protein and the inorganic compound is deposited as a deposition component on the side wall of the second distillation column 52 and deposited, the deposited component acts as a heat insulating material, and the first distillation column 52 starts the first distillation. There is a concern that the heat transfer to the tower 51 is hindered.

  However, in the internal heat exchange distillation apparatus 5 of the present embodiment, the second distillation column 52 includes the adhesion deposition preventing layer on the surface facing the inside of the first distillation column 51 on the outer side. Since the adhesion deposition preventing layer contains a fluororesin as described above, it is hydrophobic and can prevent the mixture containing proteins from adhering.

  Therefore, according to the internal heat exchange distillation apparatus 5 of the present embodiment, the internal heat exchange can be prevented by preventing the mixture of the protein and the inorganic compound from adhering to the side wall of the second distillation column 52 as a deposition component. The mold distillation column 6 can be operated smoothly.

  The internal heat exchange type distillation apparatus 5 of the present embodiment is provided with a dry vacuum pump 55 for depressurizing the inside of the first distillation column 51 in the middle of the gas supply conduit 54, and the inside of the first distillation column 51 is at atmospheric pressure or lower. And a configuration in which the second distillation column 52 is set to atmospheric pressure. However, the internal heat exchange distillation apparatus 5 of the present embodiment is not limited to the above configuration as long as the pressure in the second distillation column 52 can be made larger than the pressure in the first distillation column 51.

  For example, a compressor may be provided instead of the dry vacuum pump 55, and the first gas supplied to the second distillation column 52 via the gas supply conduit 54 may be pressurized. In this case, the inside of the 1st distillation column 51 can be made into atmospheric pressure, and the inside of the 2nd distillation column 52 can be made into the pressurized state more than atmospheric pressure.

  DESCRIPTION OF SYMBOLS 1 ... Ethanol production apparatus, 2 ... Pre-processing apparatus, 3 ... Saccharification processing apparatus, 4 ... Fermentation processing apparatus, 43 ... 1st supply conduit | pipe, 5 ... Internal heat exchange distillation apparatus, 51 ... 1st distillation tower, 52 ... Second distillation column, 54 ... Second supply conduit, 55 ... Compression means, 56 ... First extraction conduit, 57 ... Heat exchanger, 58 ... Steam pipe, 59 ... Second extraction conduit, 60 ... Condenser .

Claims (2)

A first distillation column, a second distillation column disposed inside the first distillation column and separated from the inside and the outside, and saccharification of lignocellulosic biomass as a raw material solution in the first distillation column A first supply conduit for supplying a fermentation solution obtained by fermenting the saccharified solution obtained in the step, and a first gas obtained at the top of the first distillation column and supplying the second gas to the second distillation column. Two supply conduits, a pressure difference generating means provided in the middle of the second supply conduit to make the pressure in the second distillation column higher than that in the first distillation column, and the bottom liquid of the first distillation column A first take-out conduit to be taken out, a heat exchanger for exchanging heat between the fermentation solution and the bottom liquid and preheating the fermentation solution, and a steam pipe for supplying steam directly into the first distillation column. Heating means for heating one distillation column, a second extraction conduit for taking out the second gas obtained at the top of the second distillation column, And a condenser for cooling and liquefying the second gas, and transferring the heat of the second distillation column to the first distillation column using the side wall of the second distillation column as a heat transfer surface In an internal heat exchange type distillation apparatus,
Provided on the side wall of the second distillation column is an adhesion / deposition prevention layer for preventing precipitation components consisting of a mixture of phosphate, silicate and protein contained in the fermentation solution from being deposited and deposited;
The adhesion deposition preventing layer includes a fluororesin in a range of 12 to 34% by mass in a Ni-P alloy containing 79 to 90% by mass of Ni and 7 to 9.5% by mass of P, and is 5 μm or less. An internal heat exchange distillation apparatus characterized by having a thickness of   2. The internal heat exchange distillation apparatus according to claim 1, wherein the adhesion accumulation preventing layer is formed by electroless plating.

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