A method and apparatus for producing a second category base oil from a waste lubricating oil regenerated base oil

Abstract

The application belongs to the technical field of base oil processing and production, and provides a method and equipment for preparing a second-class base oil from regenerated base oil of waste lubricating oil, which comprises the following steps: step 1, a first stirring and adsorption kettle is used to stir and adsorb a first-class base oil waste oil, and then the waste oil is allowed to stand and settle, and then impurities are removed by a horizontal screw continuous filter to obtain an oil-containing filtrate; step 2, the oil-containing filtrate is pumped into a second stirring and adsorption kettle, silica gel is added in proportion by a powder continuous automatic metering feeder, and then stirring and adsorption are performed, and after the reaction is completed, filtration is performed by the horizontal screw continuous filter to separate out waste silica gel residue, and then a first refined base oil is obtained; step 3, the first refined base oil is pumped into a third stirring and adsorption kettle, activated clay is added in proportion by the powder continuous automatic metering feeder, and then stirring and adsorption are performed, and after the reaction is completed, filtration is performed by the horizontal screw continuous filter to separate out waste clay residue, and finally, a second-class base oil is prepared after a vacuum distillation process and a refining process.

Description

Technical Field

[0001] This invention belongs to the field of base oil processing and production technology, specifically relating to a method and equipment for preparing Group II base oil from recycled waste lubricating oil. Background Technology

[0002] Lubricating oil is a high-value-added, long-life category of petroleum products, widely used in key sectors such as transportation, industrial manufacturing, and energy and power. Waste lubricating oil contains 2%–5% deteriorated substances, with the remaining 95%–98% consisting of lubricating oil base oil components and light oils, possessing extremely high recycling value. However, waste lubricating oil also exhibits hazardous characteristics such as toxicity and flammability, and improper disposal can easily cause soil, water, and air pollution. Therefore, the resource-based recycling of waste lubricating oil is of great significance for conserving petroleum resources and protecting the ecological environment.

[0003] Traditional waste lubricating oil regeneration processes mainly include sulfuric acid-clay refining and hydrorefining. The sulfuric acid-clay refining process removes non-ideal components such as gums and asphaltenes through concentrated sulfuric acid sulfonation, followed by decolorization via clay adsorption. This process has significant drawbacks: sulfuric acid reacts with olefins and aromatics to produce large amounts of difficult-to-treat acid sludge, causing secondary pollution; it also destroys some ideal components, resulting in low yield and unstable quality, producing only Class I base oils, which is insufficient to meet high-end demands.

[0004] Hydrorefining can convert Group I base oils into Group II base oils. Group II base oils are produced through a combination of solvent processing and hydrorefining, primarily through chemical processes. This process alters the hydrocarbon structure and results in products with fewer impurities, a saturated hydrocarbon content >90%, a viscosity index of 90–120, oxidation stability >220 min, excellent demulsibility, and superior low-temperature soot dispersibility. However, this process still suffers from drawbacks such as high cost, large equipment investment, short production cycle, poor safety and stability, and low efficiency. Furthermore, the products contain significant amounts of unsaturated hydrocarbons, aromatic hydrocarbons, gums, and non-metallic organic compounds such as N, O, S, Cl, and P, which severely affect oxidation stability, viscosity index, and demulsibility, especially basic nitrogen compounds.

[0005] Therefore, developing a method and equipment for regenerating Group II base oil from waste lubricating oil with a simple process flow, high impurity removal efficiency, stable product quality, and good economic efficiency has important practical significance and broad application prospects. Summary of the Invention

[0006] The purpose of this invention is to provide a method and equipment for preparing Group II base oil from waste lubricating oil recycled base oil, which solves the problems of catalyst poisoning and complex process flow in the prior art, and realizes the efficient preparation of Group II base oil from waste Group I base oil.

[0007] The objective of this invention can be achieved through the following technical solutions: The first aspect of this invention provides a method for preparing Group II base oils from recycled waste lubricating oil base oils, comprising the following steps: Step 1: Add a type of base oil waste oil into the first stirred adsorption vessel for stirring and adsorption, let it stand and settle, and then remove impurities through a horizontal spiral continuous filter to obtain oil-containing filtrate. Step 2: Pump the oily filtrate obtained in Step 1 into the second stirred adsorption vessel, add silica gel in proportion through a continuous automatic powder metering feeder, stir and adsorb, and after the reaction is completed, filter it through a horizontal spiral continuous filter to separate the waste silica gel residue and obtain primary refined base oil. Step 3: Pump the primary refined base oil obtained in Step 2 into the third stirred adsorption vessel. Add activated clay in proportion through a continuous automatic powder metering feeder, and stir and adsorb. After the reaction is completed, filter it through a horizontal spiral continuous filter to separate the waste clay residue. Finally, after vacuum distillation and refining, the second-class base oil is obtained.

[0008] As a further embodiment of the present invention, the reaction temperature of the first stirred adsorption vessel in step 1 is 30-50 °C, and the stirring adsorption time is 30-100 min.

[0009] As a further embodiment of the present invention, the reaction temperature of the second stirred adsorption vessel in step 2 is 20–40 °C.

[0010] As a further embodiment of the present invention, the stirring speed of the second stirred adsorption vessel in step 2 is 80-100 r / min.

[0011] As a further embodiment of the present invention, the amount of silica gel added in step 2 is 3% to 8% of the mass of the oily filtrate.

[0012] As a further aspect of this invention, the silica gel in step 2 has a pore size of 8–15 nm. By rationally controlling the pore size of the silica gel, it effectively adsorbs oxidation products, acidic substances, some aromatic hydrocarbons, and residual additive degradation products from waste oil, exhibiting high selective adsorption capacity. Simultaneously, the silica gel possesses strong mechanical strength and wear resistance, and is not easily broken during stirring to generate fine dust, thus effectively avoiding problems such as silica gel powder clogging subsequent equipment, enabling long-term stable operation.

[0013] As a further embodiment of the present invention, the reaction temperature in the third stirred adsorption vessel in step 3 is 90–110 °C.

[0014] As a further embodiment of the present invention, the amount of activated clay added in step 3 is 3% to 8% of the mass of the primary refined base oil.

[0015] As a further aspect of the present invention, the particle size of the activated clay in step 3 is 50–80 μm. When the particle size of the activated clay is too large, it tends to result in a smaller specific surface area, thereby reducing the number of adsorption active sites and significantly decreasing the adsorption capacity for colloids, asphaltenes, and polar impurities. When the particle size is too small, it tends to result in a larger specific surface area. Although the adsorption activity is high, it easily penetrates the filter medium, causing product turbidity and making it difficult to be effectively separated by conventional filtration equipment.

[0016] The second aspect of the present invention provides an apparatus for preparing Class II base oil from waste lubricating oil recycled base oil, including a stirred adsorption kettle, a horizontal spiral continuous filter, a powder continuous automatic metering feeder, and a distillation kettle.

[0017] The beneficial effects of this invention are: This invention provides a method for preparing Group II base oil from recycled waste lubricating oil. The method primarily involves a silica gel refining process, where the amount and particle size of the silica gel are carefully controlled to effectively remove metal particles, gums, asphaltenes, and aging products from the waste Group I lubricating oil. Simultaneously, the second stirred adsorption vessel is kept at a low temperature to facilitate the selective adsorption of oxidation products and acidic substances by the silica gel, avoiding high-temperature competitive adsorption. Subsequently, activated clay is added for deep adsorption refining, further removing residual gums, polar impurities, and pigments, providing clean refined oil for subsequent vacuum distillation and ensuring the final product meets API Group II base oil standards. This invention also employs a three-stage temperature gradient adsorption process, sequentially using low-temperature sedimentation, low-temperature silica gel adsorption, and high-temperature activated clay adsorption to synergistically remove metal particles, gums, asphaltenes, oxidation products, and polar impurities from the waste lubricating oil, achieving efficient conversion of waste Group I base oil into high-quality Group II base oil.

[0018] This invention employs adsorption purification instead of traditional hydrogenation pretreatment, eliminating the need for expensive hydrogenation catalysts and fundamentally solving the catalyst poisoning problem caused by metal impurities in waste oil. Simultaneously, it requires less equipment investment, operates under milder conditions, and offers high safety, significantly reducing production costs and demonstrating excellent economic efficiency. Furthermore, the waste bleaching clay residue and waste silica gel residue generated by this invention can be recycled and utilized, reducing solid waste emissions and avoiding secondary pollution. Compared to the traditional sulfuric acid-bleaching clay process, it produces no acid slag, is highly environmentally friendly, and aligns with the development direction of green chemistry and the circular economy.

[0019] This invention provides a method for preparing Group II base oil from recycled waste lubricating oil. This method is simple and easy to operate, and the resulting Group II base oil meets the API Group II base oil standard. Compared with existing hydrorefining base oil technology, it has lower cost, requires less equipment investment, and is highly safe, thus having broad application prospects. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. For example, there are instances where detailed descriptions of well-known matters or repeated descriptions of actually identical structures are omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter of the claims.

[0021] The performance parameters of a type of base oil waste oil used in the embodiments and comparative examples of this invention are shown in the table below:

[0022] Example

[0023] Example 1

[0024] This embodiment provides a method for preparing Group II base oil from recycled waste lubricating oil, including the following steps: Step 1: Add a type of base oil waste oil into the first stirred adsorption vessel for stirring and adsorption. The temperature of the first stirred vessel is controlled at 35 ℃ and the stirring adsorption time is 60 min. After standing and settling, remove impurities through a horizontal spiral continuous filter to obtain oil-containing filtrate. Step 2: Pump the oily filtrate obtained in Step 1 into the second stirred adsorption vessel. The temperature of the second stirred adsorption vessel is controlled at 25 ℃ and the stirring speed is 80 r / min. Silica gel (3% of the mass of the oily filtrate and 9 nm pore size) is added in proportion by a continuous automatic powder metering feeder. Stirring and adsorption are carried out. After the reaction is completed, the mixture is filtered by a horizontal spiral continuous filter to separate the waste silica gel residue and obtain primary refined base oil. Step 3: Pump the primary refined base oil obtained in Step 2 into the third stirred adsorption vessel. Add activated clay (3% of the mass of the primary refined base oil, with a particle size of 50 μm) in proportion using a continuous automatic powder metering feeder. Stir and adsorb the mixture. The temperature of the third stirred adsorption vessel is controlled at 95 ℃. After the reaction is completed, filter the mixture through a horizontal spiral continuous filter to separate the waste clay residue. Finally, after vacuum distillation and refining, the second-class base oil is obtained.

[0025] Example 2

[0026] The only difference from Example 1 is that the stirring temperature and stirring time in the first stirring vessel are different in step 1: Step 1: Add a type of base oil waste oil into the first stirred adsorption vessel for stirring and adsorption. The temperature in the first stirred vessel is controlled at 48 ℃, and the stirring and adsorption time is 80 min. After settling, remove impurities by a horizontal spiral continuous filter to obtain oil-containing filtrate.

[0027] Example 3

[0028] The only difference from Example 1 is that the stirring temperature and stirring speed of the second stirring vessel in step 2 are different: Step 2: Pump the oily filtrate obtained in Step 1 into the second stirred adsorption vessel. The temperature of the second stirred adsorption vessel is controlled at 40 ℃ and the stirring speed is 100 r / min. Silica gel (3% of the mass of the oily filtrate and 9 nm pore size) is added in proportion by a continuous automatic powder metering feeder. Stirring and adsorption are carried out. After the reaction is completed, the mixture is filtered by a horizontal spiral continuous filter to separate the waste silica gel residue and obtain primary refined base oil.

[0029] Example 4

[0030] The only difference from Example 1 is the amount and pore size of the silica gel added in step 2: Step 2: Pump the oily filtrate obtained in Step 1 into the second stirred adsorption vessel. The temperature of the second stirred adsorption vessel is controlled at 25 ℃ and the stirring speed is 80 r / min. Silica gel (8% of the mass of the oily filtrate and 14 nm pore size) is added in proportion by a powder continuous automatic metering feeder. Stirring and adsorption are carried out. After the reaction is completed, the mixture is filtered by a horizontal spiral continuous filter to separate the waste silica gel residue and obtain primary refined base oil.

[0031] Example 5

[0032] The only difference from Example 1 is the amount and particle size of the activated clay added in step 3: Step 3: Pump the primary refined base oil obtained in Step 2 into the third stirred adsorption vessel. Add activated clay (7.8% of the mass of the primary refined base oil, with a particle size of 75 μm) in proportion using a continuous automatic powder metering feeder. Stir and adsorb the mixture. The temperature of the third stirred adsorption vessel is controlled at 95 ℃. After the reaction is completed, filter the mixture through a horizontal spiral continuous filter to separate the waste clay residue. Finally, after vacuum distillation and refining, the second-class base oil is obtained.

[0033] Example 6

[0034] The only difference from Example 1 is that the stirring temperature of the third reactor in step 3 is different: Step 3: Pump the primary refined base oil obtained in Step 2 into the third stirred adsorption vessel. Add activated clay (3% of the mass of the primary refined base oil, with a particle size of 50 μm) in proportion using a continuous automatic powder metering feeder. Stir and adsorb the mixture. The temperature of the third stirred adsorption vessel is controlled at 110 ℃. After the reaction is completed, filter the mixture through a horizontal spiral continuous filter to separate the waste clay residue. Finally, after vacuum distillation and refining, the second-class base oil is obtained.

[0035] Comparative Example

[0036] Comparative Example 1

[0037] The only difference from Example 1 is that the stirring temperature and stirring time in the first stirring vessel are different in step 1: Step 1: Add a type of base oil waste oil into the first stirred adsorption vessel for stirring and adsorption. The temperature in the first stirred vessel is controlled at 20 ℃, and the stirring and adsorption time is 20 min. After settling, the oil is then removed by a horizontal spiral continuous filter to obtain an oil-containing filtrate.

[0038] Comparative Example 2

[0039] The only difference from Example 1 is that the stirring temperature and stirring speed of the second stirring vessel in step 2 are different: Step 2: Pump the oily filtrate obtained in Step 1 into the second stirred adsorption vessel. The temperature of the second stirred adsorption vessel is controlled at 53 ℃ and the stirring speed is 70 r / min. Silica gel (3% of the mass of the oily filtrate and 9 nm pore size) is added in proportion by a powder continuous automatic metering feeder. Stirring and adsorption are carried out. After the reaction is completed, the mixture is filtered by a horizontal spiral continuous filter to separate the waste silica gel residue and obtain primary refined base oil.

[0040] Comparative Example 3

[0041] The only difference from Example 1 is the amount of silica gel added in step 2: Step 2: Pump the oily filtrate obtained in Step 1 into the second stirred adsorption vessel. The temperature of the second stirred adsorption vessel is controlled at 25 ℃ and the stirring speed is 80 r / min. Silica gel (10.2% of the mass of the oily filtrate, pore size of 9 nm) is added in proportion by a powder continuous automatic metering feeder. Stirring and adsorption are carried out. After the reaction is completed, the mixture is filtered by a horizontal spiral continuous filter to separate the waste silica gel residue and obtain primary refined base oil.

[0042] Comparative Example 4

[0043] The only difference from Example 1 is that the pore size of the silicone in step 2 is different: Step 2: Pump the oily filtrate obtained in Step 1 into the second stirred adsorption vessel. The temperature of the second stirred adsorption vessel is controlled at 25 ℃, and the stirring speed is 80 r / min. Silica gel (3% of the mass of the oily filtrate, pore size 6 nm) is added in proportion using a continuous automatic powder metering feeder. Stirring and adsorption are carried out. After the reaction is completed, the mixture is filtered by a horizontal spiral continuous filter to separate the waste silica gel residue, obtaining primary refined base oil. Comparative Example 5 The only difference from Example 1 is the amount of activated clay added in step 3: Step 3: Pump the primary refined base oil obtained in Step 2 into the third stirred adsorption vessel. Add activated clay (1.8% of the mass of the primary refined base oil, with a particle size of 50 μm) in proportion using a continuous automatic powder metering feeder. Stir and adsorb the mixture. The temperature of the third stirred adsorption vessel is controlled at 95 ℃. After the reaction is completed, filter the mixture through a horizontal spiral continuous filter to separate the waste clay residue. Finally, after vacuum distillation and refining, the second-class base oil is obtained.

[0044] Comparative Example 6

[0045] The only difference from Example 1 is the particle size of the activated clay in step 3: Step 3: Pump the primary refined base oil obtained in Step 2 into the third stirred adsorption vessel. Add activated clay (3% of the mass of the primary refined base oil, with a particle size of 100 μm) in proportion using a continuous automatic powder metering feeder. Stir and adsorb the mixture. The temperature of the third stirred adsorption vessel is controlled at 95 ℃. After the reaction is completed, filter the mixture through a horizontal spiral continuous filter to separate the waste clay residue. Finally, after vacuum distillation and refining, the second-class base oil is obtained.

[0046] Comparative Example 7

[0047] The only difference from Example 1 is that the stirring temperature of the third reactor in step 3 is different: Step 3: Pump the primary refined base oil obtained in Step 2 into the third stirred adsorption vessel. Add activated clay (3% of the mass of the primary refined base oil, with a particle size of 50 μm) in proportion using a continuous automatic powder metering feeder. Stir and adsorb the mixture. The temperature of the third stirred adsorption vessel is controlled at 80 ℃. After the reaction is completed, filter the mixture through a horizontal spiral continuous filter to separate the waste clay residue. Finally, after vacuum distillation and refining, the second-class base oil is obtained.

[0048] Comparative Example 8

[0049] The only difference from Example 1 is that silica gel is added in step 2, while activated clay is not added in step 3. A method for preparing Group II base oil from recycled waste lubricating oil base oil includes the following steps: Step 1: Add a type of base oil waste oil into the first stirred adsorption vessel for stirring and adsorption. The temperature in the first stirred vessel is controlled at 35 ℃ and the stirring adsorption time is 60 min. After standing and settling, remove impurities through a horizontal spiral continuous filter to obtain oil-containing filtrate. Step 2: Pump the oily filtrate obtained in Step 1 into the second stirred adsorption vessel. The temperature of the second stirred adsorption vessel is controlled at 25 ℃ and the stirring speed is 80 r / min. Silica gel (3% of the mass of the oily filtrate and 9 nm pore size) is added in proportion by a continuous automatic powder metering feeder. Stirring and adsorption are carried out. After the reaction is completed, the mixture is filtered by a horizontal spiral continuous filter to separate the waste silica gel residue and obtain primary refined base oil. Step 3: Pump the primary refined base oil obtained in Step 2 into the third stirred adsorption vessel for stirring and adsorption. The temperature of the third stirred adsorption vessel is controlled at 95 ℃. After the reaction is completed, filter it through a horizontal spiral continuous filter to separate the waste white clay residue. Finally, after vacuum distillation and refining, the second type of base oil is obtained.

[0050] Performance testing

[0051] I. The performance of recycled Group II base oils was analyzed based on the specific standard parameters of the base oils. The relevant test methods and standard indicators for Group II base oils in the industry are shown in Table 1: Table 1

[0052] II. The Group II base oils obtained in Examples 1-6 and Comparative Examples 1-9 were subjected to the above-mentioned performance tests. The test results are shown in Table 2. Table 2

[0053] As shown in Table 2, the performance of the Group II base oils obtained in Examples 1-6 all meet the API Group II base oil standards. This demonstrates that the method for preparing Group II base oils from recycled waste lubricating oil provided by this invention is reliable and has good stability. Comparing Comparative Examples 1-2 and 7 with Example 1, it is evident that insufficient stirring temperature, stirring time, and stirring in the stirred adsorption vessel can lead to incomplete adsorption, excessive impurities, and consequently, inadequate refining. Consequently, the saturated hydrocarbon content, oxidation stability, and sulfur content of the obtained Group II base oils do not meet the standards. Comparing Comparative Examples 3-4 with Example 1, it is evident that the amount and pore size of silica gel in the second stirred adsorption vessel in step 2 affect the adsorption performance of silica gel, resulting in a certain decrease in adsorption efficiency and a significant reduction in refining effect. Comparing Comparative Examples 5-6 with Example 1, it is evident that the amount and particle size of activated clay in the third stirred adsorption vessel in step 3 also affect the adsorption performance of activated clay, leading to a significant decrease in refining effect. As can be seen from the comparison between Comparative Example 8 and Example 1, the absence of activated clay in the third stirring adsorption vessel in step 3 resulted in the saturated hydrocarbon content, oxidation stability, and sulfur content of the Group II base oil being significantly substandard. This indicates that activated clay is crucial for removing gum, asphaltenes, and polar impurities, and its synergistic effect with silica gel can produce qualified Group II base oil.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. It should be understood that, in the various embodiments of this application, the sequence number of each process does not imply a sequential order of execution; some or all steps may be performed in parallel or sequentially; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0055] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application are available on the market or can be prepared by existing methods.

[0056] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions, and all technical features and optional technical features of this application can be combined to form new technical solutions.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing Group II base oil from recycled waste lubricating oil base oil, characterized in that, Includes the following steps: Step 1: Add a type of base oil waste oil into the first stirred adsorption vessel for stirring and adsorption, let it stand and settle, and then remove impurities through a horizontal spiral continuous filter to obtain oil-containing filtrate. Step 2: Pump the oily filtrate obtained in Step 1 into the second stirred adsorption vessel, add silica gel in proportion through a continuous automatic powder metering feeder, stir and adsorb, and after the reaction is completed, filter it through a horizontal spiral continuous filter to separate the waste silica gel residue and obtain primary refined base oil. Step 3: Pump the primary refined base oil obtained in Step 2 into the third stirred adsorption vessel. Add activated clay in proportion through a continuous automatic powder metering feeder, and stir and adsorb. After the reaction is completed, filter it through a horizontal spiral continuous filter to separate the waste clay residue. Finally, after vacuum distillation and refining, the second-class base oil is obtained.

2. The method for preparing Group II base oil from recycled waste lubricating oil according to claim 1, characterized in that, In step 1, the reaction temperature of the first stirred adsorption vessel is 30–50 °C, and the stirring adsorption time is 30–100 min.

3. The method for preparing Group II base oil from recycled waste lubricating oil according to claim 1, characterized in that, In step 2, the reaction temperature of the second stirred adsorption vessel is 20–40 °C.

4. The method for preparing Group II base oil from recycled waste lubricating oil according to claim 1, characterized in that, In step 2, the stirring speed of the second stirred adsorption vessel is 80-100 r / min.

5. The method for preparing Group II base oil from recycled waste lubricating oil according to claim 1, characterized in that, In step 2, the amount of silica gel added is 3% to 8% of the mass of the oily filtrate.

6. The method for preparing Group II base oil from recycled waste lubricating oil according to claim 1, characterized in that, In step 2, the pore size of the silica gel is 8–15 nm.

7. The method for preparing Group II base oil from recycled waste lubricating oil according to claim 1, characterized in that, The reaction temperature in the third stirred adsorption vessel in step 3 is 90–110 °C.

8. The method for preparing Group II base oil from recycled waste lubricating oil according to claim 1, characterized in that, In step 3, the amount of activated clay added is 3% to 8% of the mass of the primary refined base oil.

9. The method for preparing Group II base oil from recycled waste lubricating oil according to claim 1, characterized in that, The particle size of the activated clay in step 3 is 50–80 μm.

10. An apparatus for preparing Group II base oils from waste lubricating oil regenerated base oil as described in claim 1, characterized in that: This includes stirred adsorption kettles, horizontal spiral continuous filters, powder continuous automatic metering feeders, and distillation kettles.

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