Method for removing organochlorine compounds in kitchen waste grease
By combining an aqueous reaction system with a dechlorinating agent, organochlorine compounds in kitchen waste oil are efficiently removed, solving the problems of low removal efficiency and high cost in existing technologies. This achieves safe and economical organochlorine removal, improves oil quality and yield, and reduces wastewater treatment load.
Patent Information
- Application Number
- CN202511550162.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-28
- Publication Date
- 2026-01-23
AI Technical Summary
Existing technologies are insufficient to efficiently remove organochlorine compounds from waste cooking oils, leading to equipment corrosion and catalyst performance degradation under hydrogenation process conditions, affecting stable operation of the unit and increasing maintenance costs.
An aqueous reaction system is used, and dechlorination agents such as sodium stearate, sodium dimer, sodium rosinate, sodium hydrogen phthalate, sodium salicylate, sodium butyrate, or sodium p-toluenesulfonate are added and mixed with waste cooking oil. After heating and reaction, the oil phase and aqueous phase are separated. The oil phase is dehydrated and the aqueous phase is recycled. The reaction temperature is 150~220 ℃, the time is 30~300 min, and the amount of dechlorination agent added is 2%~8%.
It achieves efficient, safe, and low-cost removal of organochlorine, reduces equipment safety risks and operating costs, improves oil quality and yield, reduces wastewater treatment load, and conforms to the principles of green chemistry.
Smart Images
Figure CN121379737A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of waste edible oil resource utilization and pollutant treatment, and particularly relates to a method for removing organic chlorine compounds in kitchen waste oil. BACKGROUND
[0002] Among various types of raw materials for biodiesel, the second-generation non-grain raw material represented by waste edible oil is of great concern due to its low cost, wide source and waste resource utilization. However, the composition of kitchen waste oil is complex, containing various impurities, and the presence of chlorine is a key technical bottleneck restricting its high-quality utilization. The chlorine in kitchen waste oil can be divided into inorganic chlorine (such as sodium chloride) and organic chlorine (such as chlorinated fatty acids, chlorinated pesticide residues, etc.). The existing pretreatment processes (such as electric desalting, water washing, etc.) can effectively remove inorganic chlorine, but the removal efficiency of organic chlorine compounds with stable structure and high boiling point is low. When kitchen waste oil is used as a raw material to produce hydrogenated biodiesel (HVO), it needs to be treated under hydrogenation process conditions. Under such conditions, chlorides can be converted into hydrogen chloride, which can cause equipment corrosion, plugging and catalyst performance degradation, resulting in unstable operation of the device, shortened catalyst life and increased maintenance costs.
[0003] To avoid the above problems, a pretreatment technology capable of efficiently and deeply removing organic chlorine in kitchen waste oil is developed, which can stably control the total chlorine content at a low level. This is of great significance to break through the technical bottleneck of the industry, ensure the long-term stable operation of the subsequent hydrogenation device, and improve the economic efficiency and competitiveness of the entire industry chain. SUMMARY
[0004] The present application overcomes the defects of low removal efficiency, complex process and high cost in the prior art method for removing organic chlorine from kitchen waste oil, and provides a method for efficiently, economically and industrially removing organic chlorine compounds from kitchen waste oil.
[0005] To solve the above technical problems, the present application adopts the following technical solutions:
[0006] A method for removing organic chlorine compounds from kitchen waste oil, water and a dechlorination agent are added to the kitchen waste oil, and the reaction is heated; after the reaction is completed, the oil phase and the water phase are separated by cooling and standing; the oil phase is dehydrated to obtain dechlorinated kitchen waste oil; the water phase is used for the next batch of treatment; the dechlorination agent is one or more of sodium stearate, sodium dimerate, sodium abietate, sodium hydrogen phthalate, sodium salicylate, sodium butyrate or sodium p-toluenesulfonate.
[0007] The method for removing organic chlorine compounds from kitchen waste oil, the reaction temperature is 150-220 DEG C, and the reaction time is 30-300 min.
[0008] The method for removing organic chlorine compounds in the kitchen waste oil, the water is added in an amount of 30% to 200% of the mass of the pretreated kitchen waste oil, and the dechlorination agent is added in an amount of 2% to 8% of the mass of the pretreated kitchen waste oil.
[0009] The method for removing organic chlorine compounds in the kitchen waste oil, the water is added in an amount of 30% to 100% of the mass of the pretreated kitchen waste oil, and the dechlorination agent is added in an amount of 4% to 8% of the mass of the pretreated kitchen waste oil.
[0010] The method for removing organic chlorine compounds in the kitchen waste oil, the reaction temperature is 190 to 210 ℃, and the reaction time is 120 to 240 min.
[0011] The method for removing organic chlorine compounds in the kitchen waste oil, comprising the following steps:
[0012] (1) Pretreatment: filtering and washing the kitchen waste oil to remove solid suspended matter and inorganic chlorine, to obtain pretreated kitchen waste oil
[0013] (2) Mixing: adding water and a dechlorination agent to the pretreated kitchen waste oil and mixing uniformly;
[0014] (3) Reaction: placing the mixture obtained in step (2) in a sealed container and heating to react;
[0015] (4) Separation and post-treatment: cooling the mixture after reaction to below 100 ℃, standing to separate into oil phase and water phase; the oil phase is dehydrated to obtain dechlorinated kitchen waste oil;
[0016] (5) Water phase reuse: the water phase obtained in step (4) is directly used in the dechlorination treatment step (2) of the next batch of kitchen waste oil;
[0017] (6) Repeating steps (1) to (5).
[0018] The method for removing organic chlorine compounds in the kitchen waste oil, the dechlorination agent is sodium p-toluenesulfonate, the water is added in an amount of 50% of the mass of the pretreated kitchen waste oil, and the sodium p-toluenesulfonate is added in an amount of 6% of the mass of the pretreated kitchen waste oil.
[0019] The method for removing organic chlorine compounds in the kitchen waste oil, the heating reaction temperature is 200 ℃, the reaction time is 180 min, and the stirring speed is 600 r / min.
[0020] The method for removing organic chlorine compounds in the kitchen waste oil, the water phase is repeatedly circulated for 9 times.
[0021] Compared with the prior art, the kitchen waste oil organic chlorine removal method provided by the application has the following beneficial effects:
[0022] (1) High safety, mild operating conditions: The application adopts a water phase reaction system and is carried out under relatively low pressure, without the high-pressure hydrogen environment necessary for traditional hydrogenation dechlorination technology, thereby greatly reducing the safety risks such as hydrogen explosion and hydrogen embrittlement, and significantly reducing the requirements for equipment materials and operating personnel.
[0023] (2) Low equipment investment and operating cost: The method does not require expensive hydrogenation reactors, hydrogen delivery and storage systems, and complex safety monitoring facilities, and the main equipment is conventional mixing, heating and separation devices, with low equipment investment and maintenance cost. At the same time, the water phase recycling mechanism reduces the consumption of fresh water and dechlorination agent, further reducing the operating cost.
[0024] (3) Environmentally friendly, less wastewater: Since the dechlorination agent is added in excess and the water phase after the reaction can be directly reused for the next batch production, the process greatly reduces the generation of chlorine-containing wastewater that needs to be treated, realizes the closed-loop circulation of the reaction medium, and reduces the wastewater treatment load and cost from the source, in line with the principles of green chemical industry.
[0025] (4) Good oil quality, high yield: The application removes chlorine elements by chemical reaction under relatively mild conditions, effectively avoiding side reactions such as excessive cracking, polymerization and carbonization of oil caused by high-temperature cracking, so the quality of the treated kitchen waste oil is better, and the chlorine removal rate before and after the reaction can reach 87.0, and the oil yield is 96.5. BRIEF DESCRIPTION OF DRAWINGS
[0026] Figure 1 The flowchart of the dechlorination of the waste edible oil provided by the application. DETAILED DESCRIPTION
[0027] The technical solutions of the application will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to exemplarily illustrate and explain the application, and should not be interpreted as limiting the scope of protection of the application. Any technical solution realized based on the above content of the application belongs to the protection scope of the application.
[0028] The chlorine content of the refined dechlorinated oil is determined by microcoulometry, and the chlorine removal rate is calculated. The organic chlorine removal rate is calculated according to the following formula:
[0029] ;
[0030] In the formula, D is the organic chlorine removal rate, O0 is the organic chlorine content of the kitchen waste oil after pretreatment, and O1 is the organic chlorine content of the kitchen waste oil after dechlorination reaction.
[0031] Calculate the yield of waste cooking oil using the following formula:
[0032] ;
[0033] In the formula, Y—the yield of waste cooking oil, W r —Weight of pretreated kitchen waste oil, W m —Weight of waste cooking oil.
[0034] Example 1
[0035] This embodiment illustrates the effectiveness of different dechlorinating agents in the method for removing organochlorine from waste cooking oil. Raw material: Commercially available waste cooking oil was used as the raw material. Solid suspended matter was removed by filtration, inorganic chlorine was removed by washing with room temperature tap water, and water was removed by heating at 120°C for 1 hour. The measured organochlorine content was 169.1 ppm.
[0036] Method: 100 g of the pretreated waste cooking oil was placed in a 500 mL high-pressure reactor. 100 g of water (water to oil mass ratio 1:1) and 5 g of dechlorinating agent (dechlorinating agent amount 5% of oil mass) were added sequentially. The reactor was sealed and reacted at 180℃ and a stirring speed of 600 r / min for 2 h. After the reaction, the mixture was cooled to below 80℃ and transferred to a separatory funnel for standing and separation to obtain the oil phase and water phase. The oil phase was heated at 120℃ for 1 h to remove water, yielding refined dechlorinated oil. The process flow diagram is shown below. Figure 1 As shown.
[0037] The test results for different dechlorinating agents are shown in Table 1 below. Among them, group 0# has no dechlorinating agent added, group 1# has sodium stearate, group 2# has sodium dimer, group 3# has sodium rosinate, group 4# has sodium hydrogen phthalate, group 5# has sodium salicylate, group 6# has sodium butyrate, and group 7# has sodium p-toluenesulfonate.
[0038] Table 1. Effects of different dechlorinating agents on the dechlorination of waste edible oils
[0039]
[0040] As shown in Table 1, the organic chlorine content in kitchen waste oil decreased only slightly when no dechlorinating agent was added. However, after adding the dechlorinating agent, the organic chlorine content in kitchen waste oil decreased significantly, indicating that the dechlorinating agent can effectively remove organic chlorine from kitchen waste oil, and the removal rate is significantly higher than that of the blank control group.
[0041] Example 2
[0042] This example is used to investigate the effect of reaction temperature on the removal efficiency of organochlorine.
[0043] The waste cooking oil used was the same as in Example 1. The dechlorination agent was fixed as sodium p-toluenesulfonate (added at 5% of the oil mass), the water-to-oil mass ratio was 1:1, and the reaction time was 2 hours. Experiments were conducted by varying the reaction temperature, while other operating procedures remained the same as in Example 1. The dechlorination effects at different reaction temperatures are shown in Table 2.
[0044] Table 2. Effects of different dechlorination temperatures on the dechlorination of kitchen waste oil.
[0045]
[0046] The results showed that the chlorine removal rate gradually increased with increasing reaction temperature. The dechlorination effect was significantly improved when the reaction temperature reached 180 °C. Further increasing the temperature could further reduce the organic chlorine content; when the temperature reached 210 °C, the chlorine content decreased to 24.96%, but the yield was only 91.9%, indicating that temperature has a significant impact on both the dechlorination effect and the yield of waste cooking oil. In addition, pressure monitoring showed that the pressure gradually increased with rising temperature, without any significant change. Considering both the dechlorination effect and the yield of waste cooking oil, 200 °C was ultimately selected as the optimal temperature for the dechlorination reaction.
[0047] Example 3
[0048] This example is used to investigate the effect of reaction time on the removal efficiency of organochlorine.
[0049] The waste cooking oil used was the same as in Example 1. The dechlorination agent was fixed as sodium p-toluenesulfonate, the water-to-oil mass ratio was 1:1, the reaction temperature was 200 °C, and the reaction time was varied during the experiment. Other operating procedures were the same as in Example 1. The dechlorination effect results at different reaction times are shown in Table 3.
[0050] Table 3. Effects of different reaction times on dechlorination of kitchen waste oil
[0051]
[0052] The results showed that the removal rate of organochlorine generally increased with the extension of reaction time. When the reaction time increased to 180 min, the dechlorination effect gradually improved, reaching a removal rate of 85.3%. Subsequently, as the reaction time increased to 240 min and above, the removal rate still increased slightly, but the rate of increase slowed significantly, finally reaching 85.9% at 300 min. This indicates that in this reaction system, the removal of organochlorine mainly occurs within the first 180 min, and further extension of the reaction time no longer significantly improves the dechlorination effect; the reaction gradually approaches equilibrium.
[0053] Example 4
[0054] This embodiment is used to investigate the effect of the amount of dechlorinating agent added on the removal effect of organochlorine.
[0055] The waste cooking oil used was the same as in Example 1. The dechlorinating agent was fixed as sodium p-toluenesulfonate, the reaction temperature was 200 °C, the water-to-oil mass ratio was 1:1, and the reaction time was 180 min. Experiments were conducted by varying the amount of dechlorinating agent added (as a percentage of the oil mass), with other operating procedures remaining the same as in Example 1. The dechlorination effect results under different dechlorinating agent addition amounts are shown in Table 4.
[0056] Table 4. Effects of different dechlorinating agent dosages on dechlorination of kitchen waste oil.
[0057]
[0058] The results showed that the chlorine removal rate further improved with increasing dechlorinating agent dosage. When the dosage increased from 2% to 6%, the dechlorination effect improved significantly. Further increasing the dosage to 8% still enhanced the dechlorination effect, but the rate of improvement plateaued. Therefore, a 6% dechlorinating agent dosage was selected as the optimal dosage.
[0059] Example 5
[0060] This embodiment is used to investigate the effect of the water-oil ratio on the removal efficiency of organochlorine.
[0061] The waste cooking oil used was the same as in Example 1. The dechlorinating agent was fixed as sodium p-toluenesulfonate, the reaction temperature was 200 °C, the reaction time was 180 min, and the amount of dechlorinating agent added was 6% of the oil mass. Experiments were conducted by varying the water-to-oil mass ratio; other operating procedures were the same as in Example 1. The dechlorination effect results under different water-to-oil ratios are shown in Table 5.
[0062] Table 5. Effects of different water-to-oil ratios on dechlorination of kitchen waste oil.
[0063]
[0064] The experimental results show that the water-to-oil ratio has a significant impact on dechlorination efficiency. The optimal dechlorination effect is achieved at a water-to-oil ratio of 1:2, with a chlorine removal rate of 88.9% and a chlorine content in the oil reduced to 18.72 ppm after dechlorination. As the water-to-oil ratio deviates from this ratio, whether the proportion of the aqueous phase increases or decreases, the dechlorination efficiency decreases to varying degrees. In summary, this invention significantly improves the removal efficiency of organochlorines by optimizing the water-to-oil mass ratio, achieving the optimal dechlorination effect at a water-to-oil ratio of 1:2, providing key parameter basis for the industrial application of this process.
[0065] Example 6
[0066] This example is used to examine the performance of dechlorination agents in continuous use.
[0067] The raw material of waste cooking oil used was the same as in Example 1. The dechlorinating agent was sodium p-toluenesulfonate, the reaction temperature was 200℃, the reaction time was 180 min, the amount of dechlorinating agent added was 6% of the oil mass, and the water:oil ratio was 1:2. All other conditions were the same as in Example 1. After each experiment, the aqueous phase separated by settling was directly added to the next round of reaction, with only a small amount of water added to compensate for moisture loss. The relationship between the number of consecutive uses of the dechlorinating agent and the dechlorination effect is shown in Table 6.
[0068] Table 6. Effect of the number of aqueous phase reuse cycles on dechlorination efficiency.
[0069]
Claims
1. A method for removing organochlorine compounds from waste cooking oil, characterized in that, Water and a dechlorinating agent are added to waste cooking oil, and the mixture is heated to react. After the reaction is completed, the mixture is cooled and allowed to stand to separate the oil phase and the water phase. The dehydrated oil phase is then used to obtain dechlorinated waste cooking oil. The dechlorinating agent is one or more of sodium stearate, sodium dimer, sodium rosinate, sodium hydrogen phthalate, sodium salicylate, sodium butyrate, or sodium p-toluenesulfonate.
2. The method for removing organochlorine compounds from waste cooking oil according to claim 1, characterized in that, The reaction temperature is 150~220 ℃, and the reaction time is 30~300 min.
3. The method for removing organochlorine compounds from waste cooking oil according to claim 1, characterized in that, The amount of water added is 30% to 200% of the mass of the pretreated kitchen waste oil, and the amount of dechlorinating agent added is 2% to 8% of the mass of the pretreated kitchen waste oil.
4. The method for removing organochlorine compounds from waste cooking oil according to claim 1, characterized in that, The reaction mixture was cooled to below 100 °C; the resulting aqueous phase was directly used for the dechlorination treatment of the next batch of kitchen waste oil.
5. The method for removing organochlorine compounds from waste cooking oil according to claim 1, characterized in that, The amount of water added is 30% to 100% of the weight of the pretreated kitchen waste oil, and the amount of dechlorinating agent added is 4% to 8% of the weight of the pretreated kitchen waste oil.
6. The method for removing organochlorine compounds from waste cooking oil according to claim 1, characterized in that, The reaction temperature is 190~210 ℃, and the reaction time is 120~240 min.
7. The method for removing organochlorine compounds from waste cooking oil according to claim 1, characterized in that, Includes the following steps: (1) Pretreatment: The waste cooking oil is filtered and washed with water to obtain pretreated waste cooking oil; (2) Mixing: Add water and dechlorinating agent to the pretreated kitchen waste oil and mix evenly; (3) Reaction: Place the mixture obtained in step (2) in a sealed container and heat it to react; (4) Separation and post-processing: The mixture after reaction is cooled to below 100 °C, allowed to stand and separate into layers, and the oil phase and water phase are obtained; the oil phase is dehydrated to obtain dechlorinated kitchen waste oil; (5) Aqueous phase reuse: The aqueous phase obtained in step (4) is directly used in the dechlorination treatment step (2) of the next batch of kitchen waste oil; (6) Repeat steps (1) to (5).
8. The method for removing organochlorine compounds from waste cooking oil according to claim 1 or 7, characterized in that, The dechlorinating agent is sodium p-toluenesulfonate. The amount of water added is 50% of the mass of the pretreated kitchen waste oil, and the amount of sodium p-toluenesulfonate added is 6% of the mass of the pretreated kitchen waste oil.
9. The method for removing organochlorine compounds from waste cooking oil according to claim 1 or 7, characterized in that, The heating reaction temperature was 200 ℃, the reaction time was 180 min, and the stirring speed was 600 r / min.
10. The method for removing organochlorine compounds from waste cooking oil according to claim 1 or 7, characterized in that, The aqueous phase was repeatedly circulated 9 times.