CN201125232Y - Biodiesel Distillation Tower - Google Patents

Abstract

The utility model discloses a biodiesel distillation tower, which comprises a packed tower, an air pumping device is arranged on the top of the tower to form a vacuum, a reboiler and a feed preheater are arranged at the bottom of the tower, and the feature is that the packed tower is located The packing section below the feed inlet is filled with Pall ring packing, and the packing section above the feed inlet is filled with metal orifice corrugated structured packing. The biodiesel distillation tower can be used for refining crude biodiesel so that the crude biodiesel meets the requirements of the national biodiesel standard.

Description

Biodiesel Distillation Tower

technical field

The utility model relates to chemical equipment, in particular to a device capable of extracting refined biodiesel from crude biodiesel, so as to improve the quality of biodiesel and meet the national biodiesel standard GB/T20828-2007.

Background technique

With the rapid growth of people's demand for petrochemical products, the exploitation of non-renewable resources—oil is also gradually increasing, which makes the reserves of this non-renewable resources decrease day by day. Although new oil and gas fields are constantly being proved, based on future Considering the demand, some experts have predicted that oil resources will be exhausted in the next few decades. Therefore, finding renewable alternatives will be the direction of future technological development.

Biodiesel is extracted from renewable plants such as oil crops such as soybeans and rapeseed, or oil-bearing forest fruits such as pistachio, engineering microalgae and other oil-bearing aquatic plants, or refined from animal oils. It is a renewable clean energy. Compared with petrochemical diesel, biodiesel has low sulfur content and high oxygen content, so it is less polluting to the environment when used as fuel. In addition, biodiesel also has the advantages of good lubricity and high flash point. However, currently produced biodiesel is limited by raw materials and production processes, some products contain high content of impurities and vegetable asphalt, etc., and there is also a problem of darker color caused by the deterioration of unsaturated fatty acids, which makes some biodiesel not reach the target level. Meet the requirements of the national biodiesel standard GB/T20828-2007. Therefore, refining crude biodiesel is a main means to solve the quality problem of biodiesel.

Packed tower separation device is a commonly used chemical separation equipment. The existing packed tower separation device is usually composed of packed tower, tower internals, tower bottom reboiler, tower top condenser and feed predictor. The tower internals are mainly There are fillers, gas distributors, liquid collection distributors and other components. The reboiler, condenser and feed preheater are all independent equipment, which are respectively connected to the bottom, top and feed inlet of the packed tower through pipelines. The packing section above the feed and the section below the feed of the packed tower are filled with the same kind of packing. However, because biodiesel contains vegetable asphalt and impurities, it is not suitable for separation and purification by ordinary packed towers. In particular, the present separation device not only has many components, but also requires a large installation space and high cost, and also has the disadvantages of high energy consumption.

Utility model content

The purpose of the utility model is to provide a biodiesel distillation tower, which can be used to separate asphalt and impurities from crude biodiesel and improve the quality of refined biodiesel.

The utility model adopts the following technical solutions: a biodiesel distillation tower, including a packed tower, with an air extraction device on the top of the tower to maintain the pressure in the tower, a reboiler at the bottom of the tower, and a feed preheater and feed The pump is characterized in that: Pall ring packing is filled in the packing section below the feed inlet in the packed tower, and metal orifice corrugated structured packing is filled in the packing section above the feed inlet.

The condenser can be a tube-and-tube heat exchanger, which is installed above the packing section of the packed tower and its tube side communicates with the space inside the tower, and the upper outlet of its tube side communicates with the described air extraction device; A liquid collection distributor is installed between the tube heat exchanger and the packing section. The liquid collection tank of the liquid collection distributor communicates with the outlet at the top of the tower to extract refined diesel oil. The distributor of the liquid collection distributor disperses part of the liquid And discharged to the tower to form a reflux. to make the whole device compact.

The tube-and-tube heat exchanger can be composed of a first heat exchanger and a second heat exchanger connected in series on the tube side, the first heat exchanger is installed below the second heat exchanger, and the first heat exchanger The inlet of the shell side of the first heat exchanger is connected to the outlet of the feed pump through a pipeline, the shell side outlet of the first heat exchanger is connected to the material inlet of the feed preheater, and the shell side of the second heat exchanger is cooled by medium.

The reboiler is a distillation pot directly installed in the lower part of the packed tower and communicated with the inner space of the packed tower.

In the biodiesel distillation tower provided by the utility model, aiming at the composition characteristics of biodiesel, different packing combinations are used for the packing sections above and below the feed port, and metal orifice plates are used for the packing sections above the feed port in the tower. Corrugated structured packing, which is punched with small holes on the metal sheet, can roughly distribute the liquid in the sheet and strengthen horizontal mixing; the sheet is pressed into small corrugations to finely distribute the liquid, increase the uniform distribution of the liquid and the wetting performance of the filler, and improve mass transfer. efficiency. The use of Pall ring packing under the feed port is beneficial to block impurities and can be cleaned. As a biodiesel distillation tower, it is especially suitable for refining crude biodiesel, so that the refined product can meet the biodiesel standard GB/T20828-2007. In addition, this distillation extraction device can also be applied to the separation and refinement of other oil products.

Description of drawings

Fig. 1 is the schematic diagram of the biodiesel distillation tower of the utility model.

Detailed ways

The biodiesel distillation tower of the present invention will be further described below in conjunction with the accompanying drawings and specific examples, so as to help understand the content of the present invention.

As shown in Figure 1, the main component of the biodiesel distillation tower is a packed tower 4, and the top of the tower is connected to a pumping device composed of a vacuum buffer tank 8 and a vacuum pump (omitted in the figure) through a pipeline to maintain the vacuum degree in the tower. There is a reboiler composed of still 5 at the bottom of the tower to vaporize the liquid material again. The feed preheater 3 is used to heat the material—crude biodiesel to make the feed reach the feed temperature of the packed tower. Pall rings 41 are filled in the packing section below the feed inlet in the packed tower 4, and high-efficiency metal orifice corrugated structured packing 43 is filled in the packing section above the feed inlet. The holes can roughly distribute the liquid in the sheet and strengthen the horizontal mixing; the sheet is pressed into small corrugations to finely distribute the liquid, increase the uniform distribution of the liquid and the wetting performance of the filler, and improve the mass transfer efficiency. The height of the orifice corrugated packing plate is generally between 100mm-200mm, the diameter of the packing is slightly smaller than the inner diameter of the tower, and two adjacent plates are installed staggered at 90°. However, due to the low pressure and large flux, the use of Pall rings is conducive to the flow of heavy components in crude biodiesel, as well as blocking impurities and facilitating cleaning. The two refined diesel oil receiving tanks 6 and 7 communicate with the sump of the liquid collection distributor 44 in the tower through the discharge pipe, so as to take part of the condensate at the top of the tower to form a reflux. Both the packing and the liquid collecting and distributing device are existing products, which are selected and used according to the specific parameters of the products of different specifications provided by the manufacturer.

In order to make the device compact and reduce the consumption of cold and heat sources of the device. As shown in FIG. 1 , a condenser consisting of a tube-and-tube heat exchanger is arranged at the top of the packed tower 4 above the packing section, and its tube side communicates with the inner space of the tower. As a preferred embodiment, the tube-and-tube heat exchanger is composed of a first heat exchanger 45 and a second heat exchanger 46 connected in series on the tube side, and the first heat exchanger 45 is located below the second heat exchanger 46, both with The vertical installation of the tubes makes the tube side of the tubes directly communicate with the inside of the tower, so that the rising gas in the tower directly enters the tube side to be condensed, and the tube side outlet of the upper head of the second heat exchanger 46 is connected to the vacuum through the pipeline. Buffer tank 8 to maintain the operating pressure in the tower. Cooling water is fed into the shell side of the second heat exchanger 46 . The shell-side inlet of the first heat exchanger 45 is connected to the outlet of the feed pump 1 through the feed pipe and the flow meter 2 , and the shell-side outlet is connected to the material inlet of the feed preheater 3 . The crude biodiesel is pumped into the first heat exchanger through the feed pump 1 to exchange heat with the rising gas at the top of the tower, and then it is raised to the feed temperature of the packed tower through the feed preheater 3, so that the steam in the tower is fully utilized. The waste heat of the state material reduces the heat source used for raw material preheating, and also reduces the cold source used for condensation of the vapor at the top of the tower, achieving a comprehensive energy-saving effect. Cooling water is fed into the shell side of the second heat exchanger to further condense the uncondensed gas after passing through the first heat exchanger 45 .

The position between the first heat exchanger 45 and the filler is provided with a liquid collection distributor 44 for collecting the homing tower top condensate, and the liquid collection tank of the liquid collection distributor 44 communicates with the discharge pipe to use refined biodiesel as a finished product Extracted and collected in receiving tanks 6 and 7, the gas phase spaces of receiving tanks 6 and 7 communicate with the vacuum buffer tank 8 to maintain the vacuum of the entire system. The other part of the condensate at the top of the tower is used as reflux liquid to spread evenly to the packing section through the distributor of the liquid collecting distributor 44, and to carry out gas-liquid contact mass transfer and heat transfer with the rising gas in the packing.

In order to further make the structure of the packed tower compact and simplified, the reboiler is a still 5 directly installed in the lower part of the packed tower 4, and the distillation chamber of the still 5 communicates with the inner space of the packed tower 4, so that it flows through the Pall ring packing 41 and After the mass transfer and heat transfer, the liquid directly enters the still 5 and is reheated to vaporize components with relatively low boiling points.

As shown in Figure 1, the packing section filled with high-efficiency metal orifice corrugated structured packing above the feed inlet consists of two sections, each section has a height of 3000mm, and a gas distributor 42 is arranged below each section. The height of the packing section below the feed inlet is also 3000mm, and the inner diameter of the tower is 600mm. The volume of the bottom still 5 is 3m ³ , and the heat exchange area of the heater is 20m ² . The heat exchange area of the feed preheater 3 is 10m ² , the heat exchange area of the first heat exchanger 45 at the top of the tower is 20m ² , and the heat exchange area of the second heat exchanger 46 is 40m ² .

Steam is used as a heat source for the distillation pot 5 and the feed preheater 3 .

The crude biodiesel is sent into the first heat exchanger 45 and the feed preheater 3 by the feed pump 1, and then enters the packed tower 4 after being heated up to the feed temperature, and passes through the packing section through gas-liquid contact mass transfer and heat transfer to realize separation Components with a lower boiling point rise to the top of the tower in the form of vapor, and after being condensed by the first heat exchanger 45 and the second heat exchanger 46, a part is extracted as a discharge and is refined diesel oil, which enters the receiving tanks 6 and 7, and the other A portion is transferred downward through the packing section as reflux. Impurities with higher boiling points enter the distillation still 5 at the bottom of the still, and part of the components with a relatively lower boiling point are vaporized by heating to continue mass transfer. Material hole discharge. The distillation device is used for biodiesel refining, and the purity of the refined biodiesel product can reach 99.99%, the yield can reach more than 95%, and the quality can reach the national biodiesel standard GB/T20828-2007.

Claims (6)

1. A biodiesel distillation tower, comprising a packed tower, with a pumping device on the top of the tower to maintain the pressure in the tower, a reboiler at the bottom of the tower, a feed preheater and a feed pump, characterized in that: The packing section below the feed inlet in the packed tower is filled with Pall ring packing, and the packing section above the feed inlet is filled with metal orifice corrugated structured packing. 2. The biodiesel distillation tower as claimed in claim 1, characterized in that: the condenser is a tube-and-tube heat exchanger, which is installed above the packing section of the packed tower and its tube side communicates with the space inside the tower. The upper outlet of the tube side is connected with the air extraction device; a liquid collection distributor is installed between the tube-and-tube heat exchanger and the packing section, and the liquid collection tank of the liquid collection distributor is in common with the outlet at the top of the tower For the production of refined diesel oil, the distributor of the liquid collection distributor disperses part of the liquid and discharges it into the tower to form a reflux. 3. The biodiesel distillation tower as claimed in claim 2, characterized in that: the shell-and-tube heat exchanger is composed of a first heat exchanger and a second heat exchanger connected in series on the tube side, and the first heat exchanger The heat exchanger is installed below the second heat exchanger, the inlet of the shell side of the first heat exchanger is connected to the outlet of the feed pump through a pipeline, and the shell side outlet of the first heat exchanger is connected to the feed preheating The material inlet of the heat exchanger, and the shell side of the second heat exchanger passes through the cooling medium. 4. The biodiesel distillation tower according to any one of claims 1 to 3, characterized in that: the reboiler is a still pot directly installed in the lower part of the packed tower and communicated with the inner space of the packed tower. 5. The biodiesel distillation tower according to any one of claims 1 to 3, characterized in that: the packing section above the feed inlet is divided into two sections. 6. The biodiesel distillation tower as claimed in claim 5, characterized in that: the inner diameter of the packed tower is 600mm, and the height of each packed section is 3000mm.

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