Puralube Germany GmbH根据创新的UOP HyLube工艺操作了两家炼油厂。以废油为原料，年生产能力15万吨，这些工厂位于德国莱比锡以南约40公里的蔡茨工业园区。自2004年中期，世界上第一家此类炼油厂开始生产以来，Zeitz油田一直在生产高质量的API II组和III组基础油。2008年底，第二个工厂在同一地点投产。每年，这两个工厂消耗大约15万吨的原料。他们生产大约9万吨基础油和另外5万吨其他矿物油产品。目前约有110名员工在生产、质量保证、销售和行政部门工作。
腐蚀性成分废油原料的特性和组成千差万别，对螺杆泵的需求量很大。它们必须能够可靠地移动包含固体的液体，而不会造成过度磨损，同时还要抵抗油中所含的化学侵蚀性成分。在这种情况下，考虑Allweiler®是仅有的少数几家生产自己的定子PC泵的制造商之一，工程师可以从大约20种不同的材料中进行选择，以实现特定泵送液体的最长使用寿命。 PURALUBE所使用的定子和关节环均由Viton制成。另外，泵速与材料中的固体量相适应。在178 rpm时，泵速实际上比可能的要慢得多。更高的速度和更小的泵将是可能的。但是为了最大化使用寿命，选择了以较低速度运行的大型泵单元。结果，尽管有困难的液体，合成定子的平均使用寿命至少为6至9个月。定子和转子的特殊表面结构是这些泵的另一个优点。定子表面呈现蜂窝状结构。结合获得专利的“鲨鱼皮”转子，可实现较低的启动力和运行力，从而在运行过程中实现更高的效率和恒定的性能曲线。
原料通过反应器后，便进入主塔进行蒸馏。 除了柴油和石脑油外，这里还生产了粘度等级为P75，P160和P300的各种基础油。 产生的废气在炼油厂的加热器中进行热处理。
离心泵既用于塔中的回流，又用于基础油的最终泵送。 此时，所有固体均已分离出来，不再是选择泵技术的因素。 但是现在该过程除了可能超过300°C的温度外还涉及挥发性化合物。在塔中蒸馏期间，油温在200°C至330°C之间，对泵有很高的要求。 Allheat CTWH系列已证明是这些目的的理想选择。德国制造商Allweiler®设计了这些离心机泵。
轴密封处的温度仍然足够低，可以使用市售的机械密封而无需外部冷却。 由于机械密封是泵中对温度最敏感的部分，因此此特性对于在连续运行的工厂中保持连续，无干扰的泵送至关重要。 另外，通过上述外部冷却，投资和维护成本保持较低。 用于色谱柱回流并将产品泵送到外出储罐的泵被设计为冗余单元。
泵送液体中的低沸物会给热载体泵带来额外的压力，因此必须采用特殊的设计解决方案。 大的密封腔以及从泵中收集和清除气体的能力对于延长泵的使用寿命并提高其可靠性至关重要。 Zeitz使用的泵在最高6 bar的压力下在6m/h至19m/h之间移动。
尽管蒸馏的热条件需要使用特殊的高温泵，但在泵送最终产品时，其他因素也会起作用。 产品是部分挥发性的，温度最高约100°C。 还必须遵守TA Luft空气污染法规的规定。考虑到较低的液体温度，PURALUBE选择了Allweiler®的CNH-ML和CNH-M系列电磁耦合离心泵。这些泵是密封的，可将汽油，石脑油和柴油几乎无排放地输送到最终储罐。由于在叶轮后方装有碳化硅轴承，这些泵运行安静，甚至可以短时间空转而不会造成损坏。泵送能力在1m/h至5m/h之间，压力为6bar(g)， 泵由热传感器监控。
该工厂总共使用了77种不同设计类型的Allweiler泵。 所有泵的设计均具有防爆功能。 除了设计优势和针对各种泵送任务和液体的优化之外，所有泵都由一个供应商提供还具有其他优势：通用零件简化了备件管理，占用的资金更少，维护更容易，因为技术人员只需要一个制造商的知识。此外，授权的制造商维修中心Pumpenfabrik Leipzig GmbH还提供专业的现场支持和备件交付。
Puralube Germany GmbH operates two refineries according to the innovative UOP HyLube process. Total throughput is 150,000 metric tons per year with used oil as feedstock. The plants are located in the Zeitz industrial park, approximately 40 km south of Leipzig, Germany. Since beginning production at the world's first refinery of this type in mid-2004, the Zeitz site has been producing highquality API Group II and III base oils. In late 2008, a second plant was brought on line at the same location.Each year,the two plants consume approximately 150,000 metric tonsof feedstock. They produce about 90,000 metric tons ofbase oils and another 50,000 metric tons of other mineraloil products. Currently approximately 110 employees workin production, quality assurance, sales, and administrationat this location.
The pumps used in production must fulfill special requirements that vary depending on the step in the process. At first glance, this may be surprising since the lubricity of oil makes it one of the easiest liquids for pumps to handle.
However, the feedstock delivered in tank trucks places high demands on the pumps used to move that material: First,the chemical composition can vary. Second, the presence of solid components in the form of dirt or metal particles is also probable. A coarse screen collects larger solids, but medium-sized and smaller abrasive components can still get into the pumps. The pumps move the feedstock from the tank trucks or tank railcars to a holding tank where samples are taken. The pumps used for these tasks must resist chemically aggressive materials like benzols and naphtha while remaining insensitive to solids. Furthermore, all the pumps must have strong suction capabilities in order to draw the sometimes very viscous oil from the tanks. If the feedstock meets the minimum requirements for processing, it is pumped from the holding tanks to storage tanks. From there it moves into the high-pressure portion of the refinery. The pumps must move the material across distances of up to 500 m, sometimes overcoming a counterpressure of up to 2 bar created by a cushion of nitrogen in both holding tanks.
At PURALUBE, progressing cavity pumps fulfill all of these requirements. The company has chosen ten single-stage pumps of the AE-E series from manufacturer Allweiler®,which is part of the CIRCOR corporate group.
The widely varying characteristics and compositions of the used oil feedstock place extraordinary demands on progressing cavity pumps. They must be able to reliably move liquids containing solids without incurring excessive wear,while at the same time resisting chemically aggressive components contained in the oil. In this context, it is very important to consider that Allweiler® is one of only a few manufacturers of PC pumps that produces its own stators. Engineers choose from approximately 20 different materials to achieve the longest possible service life with the specific pumped liquid. Both the stators and joint collars used by PURALUBE are made of Viton. Additionally,pump speed is adapted to the amount of solids in the material. At 178 rpm, pump speed is actually much slower than is possible. Higher speeds and smaller pumps would have been possible. But in order to maximize service life, larger pump units running at reduced speeds were chosen. As a result, average service life of the synthetic stator is at least 6 to 9 months, despite the difficult liquid. The special surface structure of the stator and rotor is another advantage of these pumps. The stator surface exhibits a honeycomb structure. Combined with the patented "shark-skin" rotors, the results are low starting and operating forces for greater efficiency and constant performance curves during operation.
Frequency control with a start-up ramp ensures efficient and safe pumping across great distances. Starting up slowly is essential in order to bring the liquid slowly into motion and avoid cavitation.
Once the feedstock has passed through the reactors, it moves to distillation in the main column. A variety of base oils in viscosity classes P75, P160, and P300 are produced here in addition to diesel fuel and naphtha. The resulting off gas is thermally processed in the refinery's heaters.
Centrifugal pumps are used both for the return in the column as well as for final pumping of base oils. At this point, all solids have been separated out and are no longer a factor in selecting pump technology. But now the process involves volatile compounds in addition to temperatures that can exceed 300 °C.
During distillation in the column, oil temperature is between200°C and 330°C, placing high demands on the pumps.Special heat-carrier pumps of the Allheat CTWH series have shown to be ideal for these purposes. Manufacturer Allweiler®of Germany has designed these centrifugal pumps so that the temperature at the shaft seal remains low enough to use commercially available mechanical seals without external cooling. Since the mechanical seal is the most temperature-sensitive part of the pump, this characteristic is critical for maintaining continuous, disturbance-free pumping at plants that stay in operation continuously. In addition, investment and maintenance costs are kept low by foregoing external cooling. Pumps used for column returns and pumping the products to outgoing storage tanks are designed as redundant units.
Specially designed pumps
Low boilers in the pumped liquid place additional strains on the heat carrier pumps, so special design solutions must compensate. A large seal chamber and the ability to collect and remove gases from the pump are critical for extending the pump's service life and increasing its reliability.Pumps used at Zeitz move between 6 m /h and 19 m /h at a pressure of up to 6 bar.
While the thermal conditions of distillation require use of special high-temperature pumps, other factors come into play when pumping the final products. The products are partially volatile and temperatures max out at about 100 °C. The stipulations of the TA Luft air-pollution regulations must be observed as well. In view of the lower liquid temperatures,PURALUBE has selected magnetically-coupled centrifugal pumps of the CNH-ML and CNH-M series from Allweiler®.These pumps are hermetically sealed and move benzine,naphtha, and diesel to the final storage tanks virtually without emissions. With silicon carbide bearings directly behind the impeller, these pumps are quiet in operation and may even run dry for short periods without damage.Pump capacity is between 1 m /h and 5 m /h, with pressure at 6 bar(g). The pumps are monitored by thermal sensors.
In total, 77 Allweiler pumps of several different design types are used at the plant. All pumps are designed with explosion protection. Besides design benefits and optimization for a variety of pumping tasks and liquids, having a single supplier for all pumps has additional advantages:Common parts simplify spare parts management, less capital is tied up, and maintenance is easier because technicians require knowledge of only one manufacturer.Additionally, authorized manufacturer workshop Pumpenfabrik Leipzig GmbH provides competent on-site support and delivery of spare parts.