阅读说明：本技术 双功能催化高酸值油脂一步制备生物柴油工艺及连续化装置 (One-step preparation process of biodiesel by bifunctional catalysis of high-acid-value grease and continuous device ) 是由 李科 陈洁 聂小安 蒋剑春 徐俊明 于 2021-07-09 设计创作，主要内容包括：本发明涉及一种双功能催化高酸值油脂一步制备生物柴油工艺及连续化装置,采用高酸值油脂和甲醇作为原料,以固体酸碱双功能催化剂或固体酸、碱为催化剂,在同反应器中同步实现油脂中脂肪酸酯化合成脂肪酸甲酯和甘油三酯酯交换制备脂肪酸甲酯；反应器底部设有气体分布器、顶部液体分布器、上催化剂层、下催化剂层。油脂经预热后从上端注入反应器中,顺流而下；甲醇经气化后从下端注入反应器,逆流而上,与甘油三酯和脂肪酸在不同催化剂层相遇反应。反应器中温度在101～260℃之间。气体或气体产物从反应器顶端排出,液体产物从反应器底端排出,静置分层后除去甘油既得生物柴油。本发明实现高酸值油脂一步制备生物柴油,亦可实现连续化生产。(The invention relates to a one-step preparation process and a continuous device of biodiesel by bifunctional catalytic high-acid-value grease, which adopts high-acid-value grease and methanol as raw materials, takes a solid acid-base bifunctional catalyst or a solid acid and a solid base as catalysts, and synchronously realizes the esterification synthesis of fatty acid methyl ester and the transesterification preparation of triglyceride from fatty acid in the grease in the same reactor; the bottom of the reactor is provided with a gas distributor, a top liquid distributor, an upper catalyst layer and a lower catalyst layer. Preheating the grease, injecting the preheated grease into the reactor from the upper end, and flowing down; after being gasified, the methanol is injected into the reactor from the lower end and flows up in the counter-current way to meet and react with the triglyceride and the fatty acid in different catalyst layers. The temperature in the reactor is between 101 and 260 ℃. Discharging gas or gas product from the top of the reactor, discharging liquid product from the bottom of the reactor, standing for layering, and removing glycerol to obtain biodiesel. The invention realizes the one-step preparation of the biodiesel from the high acid value grease and also can realize continuous production.)

1. A one-step preparation process of biodiesel by bifunctional catalysis of high acid value grease is characterized in that: adopting high-acid-value grease and methanol as raw materials, taking a solid acid-base bifunctional catalyst or a solid acid-base bifunctional catalyst as a catalyst, and synchronously realizing the esterification synthesis of fatty acid methyl ester and the transesterification preparation of triglyceride from fatty acid in the grease in one reactor; the method comprises the following steps of preheating filtered, dehydrated and degummed pretreated grease, injecting the preheated grease into a reactor (1) from the upper end, and flowing down; and (2) injecting the gasified methanol into the reactor from the lower end, flowing up in the counter-current manner, and reacting with triglyceride and fatty acid in the high-acid-value oil in different catalytic layers, wherein the temperature in the reactor is between 101 and 260 ℃, gas or gas products are discharged from the top end of the reactor, liquid products are discharged from the bottom end of the reactor, and the glycerin is removed after standing and layering to obtain the biodiesel.

2. The one-step biodiesel preparation process by using the bifunctional catalytic high-acid-value grease as claimed in claim 1, wherein the high-acid-value grease is various waste edible oils and acidic oils.

3. The process for preparing biodiesel by one step through catalyzing high acid value grease by using double functions as claimed in claim 1, wherein the solid acid catalyst is cation exchange resin, zeolite molecular sieve solid acid, heteropoly acid, SO₄ ^2-/M_xO_yAny one of (a); the solid base catalyst is any one of anion exchange resin, metal oxides such as calcium, magnesium and the like, magnesium-aluminum hydrotalcite, SBA loaded solid base, aluminum oxide or active carbon loaded solid base; the acid-base bifunctional catalyst is any one of SBA and MCM supported bifunctional catalysts, mixed metal oxides and acid-base bifunctional silica gel.

4. The process for one-step preparation of biodiesel according to claim 1, wherein methanol is purified and then reused.

5. A continuous device applied to the one-step preparation process of biodiesel by using bifunctional catalytic high-acid-value grease is characterized by mainly comprising a reactor, wherein a gas distributor is arranged at the bottom of the reactor, a lower catalyst layer and an upper catalyst layer are sequentially arranged upwards, a liquid distributor is arranged at the top of the reactor, a heating device is further arranged in the reactor, a grease inlet of the reactor is arranged at the upper end, a methanol inlet is arranged at the lower end, a gas outlet is arranged at the top of the reactor, and a liquid product outlet is arranged at the bottom of the reactor.

6. The continuous device applied to the one-step preparation process of the biodiesel by the bifunctional catalytic high-acid-value grease as claimed in claim 4, wherein the methanol is connected with the methanol inlet of the reactor through a metering pump and a gasifier.

7. The continuous device applied to the one-step preparation process of the biodiesel by the bifunctional catalytic high-acid-value grease as claimed in claim 4, wherein the grease is connected with a grease inlet at the upper end of the reactor through a metering pump and a preheating heat exchanger.

8. The continuous device applied to the one-step preparation process of the biodiesel from the bifunctional catalytic high-acid-value grease as claimed in claim 4, wherein a gas outlet at the top of the reactor is connected with a condensing heat exchanger, and the condensing heat exchanger is connected with a methanol rectifying tower.

Technical Field

The invention relates to a one-step preparation process of biodiesel by bifunctional catalytic high-acid-value grease and a continuous device, belonging to the fields of grease chemical utilization, new energy and related equipment.

Background

Biodiesel (fatty acid methyl ester and the like) is novel environment-friendly fuel oil which is very close to the existing diesel oil in molecular weight and structure, and the production raw materials come from various renewable oils (such as rapeseed oil, soybean oil, woody oil, microbial oil, waste catering oil and the like). Although the fatty acid ester biodiesel has the advantages of wide raw material source, excellent use performance, high environmental protection performance, good engine starting performance, renewability and the like; and the vigorous development of the biodiesel has important significance for energy safety, air pollution prevention, environmental improvement, economic sustainable development and the like. However, in practical applications, many bottleneck problems are encountered, such as: most of the oil materials capable of preparing the biodiesel are edible oil, such as soybean oil, rapeseed oil, corn oil and the like, and have the problem of competing for grains with people; in addition, the wood oil materials such as catalpa oil, tung oil and the like basically have respective industries and are commonly used for synthesizing special materials, and the cost is high; the microbial oil is not high in yield, and has a cost problem; kitchen waste oil, acidified oil and the like have poor oil quality although the price of raw materials is not high, the components of the oil are mainly a mixture of triglyceride and fatty acid, and after treatment, the biodiesel can be synthesized by two steps of esterification and ester exchange, so that the process is complex and the processing cost is high. Therefore, how to reduce the raw material cost or the processing cost of the biodiesel always restricts the development of the industry, and is a problem which needs to be solved urgently by the market.

The price influence factors of the soybean oil, the woody oil and the microbial oil are relatively fixed and are difficult to reduce. Only the grease with high acid value such as the kitchen waste oil can solve the problems in the processing technology by a way of thinking and trying, and the problem is solved once and for all.

At present, the treatment of high acid value oil and fat is aimed. Alkali refining and distillation are mainly adopted, but the decarboxylation directly removes free fatty acid in grease, so that the time consumption, energy consumption and pollution are consumed, the removed fatty acid is a main group of the biodiesel, unnecessary loss is caused, and the method is not suitable for biodiesel production; the pre-esterification is a method widely adopted at present, which can convert fatty acid in high-acid-value grease into a biodiesel product and reduce loss. And the subsequent low acid value grease can be continuously prepared into the biodiesel by adopting an ester exchange method. However, compared with the conventional synthesis process, the conventional synthesis process is at least 1 time enlarged, the time is at least 1 time prolonged, the energy consumption is at least 1 time increased and the like compared with the low-acid-value grease (biodiesel can be prepared only through transesterification reaction). This seriously hinders the development process of biodiesel synthesis from low-cost high-acid-value oil.

Disclosure of Invention

Aiming at the problems of complex process, high energy consumption, long time and the like caused by the fact that pre-esterification and ester exchange are separately carried out in the existing process for synthesizing the biodiesel by the high-acid-value oil, the invention provides a one-step biodiesel preparation process by bifunctional catalysis of the high-acid-value oil and a continuous device. Firstly, the invention realizes the synchronous esterification and ester exchange process of the high acid value grease, greatly shortens the process time, and reduces the production cost and the total energy consumption; secondly, the process has strong applicability to raw materials, and can be applied to various high-acid-value oils and fats; moreover, in order to remove the byproduct water as soon as possible and promote the reaction to be carried out quickly, the process can realize the quick discharge of water vapor. Therefore, the purposes of reducing working procedures, shortening time, reducing loss, improving efficiency and reducing cost are achieved.

The technical scheme of the invention is as follows: a one-step preparation process of biodiesel by bifunctional catalysis of high-acid-value grease adopts high-acid-value grease and methanol as raw materials, takes a solid acid-base bifunctional catalyst or a solid acid and base as catalysts, and synchronously realizes the esterification synthesis of fatty acid methyl ester in grease and the transesterification preparation of fatty acid methyl ester by triglyceride in a reactor; preheating the oil subjected to filtering, dehydrating and degumming pretreatment, injecting the preheated oil into a reactor from the upper end, and flowing down; and (2) injecting the gasified methanol into the reactor from the lower end, flowing up in the counter-current manner, and reacting with triglyceride and fatty acid in the high-acid-value oil in different catalytic layers, wherein the temperature in the reactor is between 101 and 260 ℃, gas or gas products are discharged from the top end of the reactor, liquid products are discharged from the bottom end of the reactor, and the glycerin is removed after standing and layering to obtain the biodiesel.

The high-acid-value oil is various waste edible oils and acidified oils.

The solid acid catalyst is cation exchange resin, zeolite molecular sieve solid acid, heteropoly acid, SO₄ ^2-/M_xO_yAny one of (a); the solid base catalyst is any one of anion exchange resin, metal oxides such as calcium, magnesium and the like, magnesium-aluminum hydrotalcite, SBA loaded solid base, aluminum oxide or active carbon loaded solid base; the acid-base bifunctional catalyst is any one of SBA and MCM supported bifunctional catalysts, mixed metal oxides and acid-base bifunctional silica gel.

Wherein the methanol is reused after being purified.

Be applied to a bifunctional catalysis high acid value grease one-step preparation biodiesel device in technology, mainly include the reactor, wherein the bottom of reactor sets up gas distributor, upwards sets gradually down catalyst layer and last catalyst layer, sets up liquid distributor at the top at last, still is provided with heating device in the reactor, the upper end is located to the grease entry of reactor, and the lower extreme is located to the methyl alcohol import, and the top is equipped with the gas outlet, and the bottom is equipped with the export of liquid product.

The methanol is connected with a methanol inlet of the reactor through a metering pump and a gasifier.

The grease is connected with a grease inlet at the upper end of the reactor through a metering pump and a preheating heat exchanger.

The gas outlet at the top of the reactor is connected with a condensing heat exchanger, and the condensing heat exchanger is connected with a methanol rectifying tower.

Has the advantages that:

the invention can realize that the high acid value grease synchronously carries out the esterification reaction of fatty acid and the ester exchange reaction of triglyceride in the same reactor and the same reaction time period, and can synchronously realize the timely discharge of water as a byproduct of esterification, thereby effectively improving the esterification rate of fatty acid, reducing the content of fatty acid in grease, ensuring the ester exchange conversion rate, shortening the reaction time and improving the quality of the esterification product. The method technically realizes the combination of fatty acid esterification and triglyceride transesterification, and can quickly and efficiently realize the purpose of preparing the biodiesel from the high-acid-value oil, thereby realizing the purposes of shortening the reaction time, reducing the loss, improving the productivity and reducing the cost. The methanol and water produced in the production process can be reused after rectification.

The raw materials are various kinds of recovered high acid value grease such as kitchen waste oil and methanol; the catalyst is various solid acid-base or acid-base bifunctional catalysts.

Drawings

FIG. 1 is a schematic diagram of a device for continuously producing biodiesel by one step from high acid value grease.

Wherein: the reactor comprises a reactor 1, a gas distributor 2, an upper catalyst 3, a lower catalyst 4, a valve 5, a metering pump 6, a gasifier 7, a preheating heat exchanger 8, a condensing heat exchanger 9 and an internal heat exchange coil 10.

Detailed Description

A one-step preparation process of biodiesel by bifunctional catalytic high-acid-value grease and a continuous device. Adopting high-acid-value grease and methanol as raw materials, taking a solid acid-base bifunctional catalyst or a solid acid and base as the catalyst, and synchronously realizing the esterification synthesis of fatty acid methyl ester and the transesterification preparation of triglyceride from fatty acid in the grease in the same reactor; to facilitate the process, the reactor is designed with reference to a simplified schematic diagram of the apparatus (but not limited to), and the main reactor of the apparatus is provided with a bottom gas distributor, a top liquid distributor, an upper catalyst layer, a lower catalyst layer, a heating device and other components. Preheating the grease after pretreatment such as filtration, dehydration, degumming and the like, injecting the preheated grease into a reactor from the upper end, and flowing down; after being gasified, the methanol is injected into the reactor from the lower end and flows up in the counter-current way to meet and react with triglyceride and fatty acid in different catalytic layers. The temperature in the reactor is controlled to be between 101 and 260 ℃. The gas or gaseous product is discharged from the top of the reactor, wherein the methanol can be reused after purification; discharging the liquid product from the bottom end of the reactor, standing for layering, and removing glycerin to obtain the biodiesel. The method can synchronously realize esterification and ester exchange reaction of fatty acid in the high-acid-value grease, quickly realize the purpose of acid reduction and ester exchange with low loss, and bidirectionally and synchronously synthesize the biodiesel.

The method can effectively realize that the high acid value grease synchronously carries out the esterification reaction of fatty acid and the ester exchange reaction of triglyceride in the same reactor and the same reaction time period, not only can effectively reduce the content of the fatty acid, ensure the ester exchange conversion rate, shorten the reaction time and improve the quality of the esterification product.

Example 1:

raw materials: kitchen waste oil (acid value 52mgKOH/g), methanol, solid acid and alkali catalyst;

enough solid acid catalyst SiO is added₂-ZrO₂Filling the upper layer of the reactor 1; the solid base catalyst anion exchange resin fills the lower layer of the reactor 1. Raising the temperature to 120 ℃, and injecting methanol steam from a feed inlet at the lower end of the reactor; injecting kitchen waste oil from a feed inlet at the upper end of the reactor. The kitchen waste oil completes esterification reaction on the upper layer of the reactor and flows into the lower layer to complete ester exchange reaction. In the upper layer, methanol steam and water generated in the reaction are discharged from the top and are separated by a rectifying device for reuse, so that the lower layer is not influenced; the kitchen waste oil subjected to deacidification completes ester exchange reaction at the lower layer, and the generated biodiesel (methyl ester) and glycerin enter a standing tank from a bottom discharge hole. Layering to obtain coarse biodiesel oil product with acid value of 0.6 mgKOH/g.

Example 2:

raw materials: acidified oil (acid value 131mgKOH/g), methanol, solid acid and alkali catalyst;

adding sufficient solid acid catalyst SO₄ ^2-/M_xO_yFilling the upper layer of the reactor (1); the solid alkali catalyst magnesium aluminum hydrotalcite is filled in the lower layer of the reactor (1). Raising the temperature to 170 ℃, and injecting methanol steam from a feed inlet at the lower end of the reactor; the acidified oil is injected from the feed inlet at the upper end of the reactor. The acidified oil completes esterification reaction at the upper layer of the reactor and flows into the lower layer to complete transesterification reaction. In the upper layer, methanol steam and water generated in the reaction are discharged from the top and are separated by a rectifying device for reuse, so that the lower layer is not influenced; the deacidified oil completes ester exchange reaction in the lower layer, and the biodiesel (methyl ester) and glycerin enter the standing tank from the bottom discharge hole. Layering to obtain biodiesel crude oilThe acid value of the product was 0.81 mgKOH/g.

Example 3:

raw materials: kitchen waste oil (acid value 63mgKOH/g), methanol and acid-base bifunctional catalyst;

sufficient amount of acid-base bifunctional silica gel catalyst is filled into all levels of the reactor (1). Raising the temperature to 230 ℃, and injecting methanol steam from a feed inlet at the lower end of the reactor; injecting kitchen waste oil from a feed inlet at the upper end of the reactor. The kitchen waste oil flows from the upper end to the lower end and is continuously subjected to esterification and ester exchange reaction with methanol, water generated by the reaction is quickly gasified and discharged from the top, and glycerin generated by the reaction is also quickly separated and discharged from the bottom end. Rectifying the gas product at the top, and recovering methanol for reuse; and (3) allowing the bottom product to enter a standing tank, and layering to obtain a biodiesel crude product with an acid value of 0.67 mgKOH/g.

Example 4:

raw materials: high acid value grease (acid value 114mgKOH/g), methanol, solid acid and alkali catalyst;

enough solid acid catalyst aluminum oxide is loaded with H₂SO₄Filling the upper layer of the reactor (1); the lower layer of the reactor (1) is filled with a solid alkali catalyst, namely alumina supported KOH. Raising the temperature to 190 ℃, and injecting methanol steam from a feed inlet at the lower end of the reactor; injecting high acid value grease from a feed inlet at the upper end of the reactor. The high acid value grease completes esterification reaction at the upper layer of the reactor and flows into the lower layer to complete ester exchange reaction. In the upper layer, methanol steam and water generated in the reaction are discharged from the top and are separated by a rectifying device for reuse, so that the lower layer is not influenced; the high acid value grease after acid reduction completes ester exchange reaction at the lower layer, and the biodiesel (methyl ester) and the glycerin enter a standing tank from a discharge hole at the bottom. Layering to obtain coarse biodiesel oil product with acid value of 0.74 mgKOH/g.

The examples and the schematic diagrams of the apparatus are only intended to illustrate the method of implementation, any changes of process parameters, replacement of catalyst or change of the structure of the equipment, which still adopts the principle of the method, still fall within the scope of protection of the patent.