【Ten Years of Great Development in Chemical Equipment】An excellent article from 2348 to 2025! The overall modular construction approach for ethylene cracking furnaces and its advantages!
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This post was last edited by “Fish Swimming in the Desert” on May 4, 2025, at 13:25. Let’s give a thumbs up and encouragement to the achievements made in China’s chemical engineering technology and equipment. Your participation in the discussion serves as the greatest motivation! ********************** [Ten Years of Great Development in Chemical Engineering Equipment] This is a continuously updated summary thread; all are welcome to join the discussion: https://bbs.hcbbs.com/thread-3576046-1-1.html ***************** Abstract: The article analyzes and summarizes the entire process of the overall modular manufacturing, transportation, and installation of cracking furnaces used in ethylene plants. It also makes a comprehensive comparison with on-site installation methods. The results indicate that the overall modular construction approach for such furnaces is not only technically feasible but also offers numerous advantages, including shortened construction periods, reduced construction costs, minimized safety risks during construction, and effective control over environmental pollution. Furthermore, this construction method can be further optimized based on the production capabilities of individual manufacturers. The overall modular construction of cracking furnaces is a new alternative construction method. Keywords: cracking furnace, radiation zone, convection zone, overall modularization. In early ethylene cracking furnaces, due to factors such as a large number of components, diverse types, large size, heavy weight, and the vulnerability of some refractory materials making transportation difficult, construction was mostly carried out through on-site manufacturing and installation. Starting from the mid-to-late 1990s, as ethylene cracking units evolved toward larger scale and higher levels of integration, the dimensions of the cracking furnaces also continued to increase in size and height. Modular manufacturing, transportation, and installation of the convection section in pyrolysis furnaces have emerged, which not only saves time but also addresses the issue of a shortage of skilled workers for on-site construction. Since 2000, the steel structure of the radiation section of the pyrolyzer has been prefabricated in segmented modular units ； Due to the constraints of the construction site conditions, there are various methods for the modular prefabrication of the steel structure in the radiation section; both longitudinal and transverse segmentation are common. Around 2010, attempts were made to implement overall modular manufacturing, transportation, and installation for other types of industrial furnaces, but preliminary planning for the overall modular manufacturing, transportation, and installation of cracking furnaces in ethylene plants was not carried out until 2016. The following will introduce, from the perspective of on-site construction in ethylene plants, the methods and key points for overall modular manufacturing, transportation, and installation, while using a comparative approach to illustrate the advantages of overall modular manufacturing.
1 Plan Confirmation 1.1 Overall Modular Approach At the beginning of 2017, a feasibility study was conducted in a domestic petrochemical company regarding an overall modular manufacturing approach for the cracking furnaces in ethylene production facilities, and the following plan was established: all 9 cracking furnaces with a capacity of 200,000 tons per year were to be manufactured in another location using a modular approach, transported there, and then installed in place. 1.2 Overall modular construction process: The 2 heavy oil furnaces, 5 light oil furnaces, and 2 gas furnaces are constructed in accordance with the SH/T 3511【1】 standard, based on their furnace type and individual unit numbers. The manufacturer requires a construction site at the location capable of building 9 pyrolysis units simultaneously, along with the necessary lifting equipment and shipping docks. Per furnace, module manufacturing is maximized based on the lifting capacity of the lifting equipment available at the site; the overall assembly is divided into three sections: the radiation section, the convection section, and the smoke collection hood (including the steam drum and platform). The construction site is shown in Figure 1, and the construction process flow is shown in Figure 2.
The overall module construction process is as follows: 1) The furnace shells of the two radiation chambers in the radiation section are separately assembled into box modules on the ground, with each module being located on a temporary foundation. 2 After the radiation box and transition sections are completed, the radiation furnace tubes are stored, and the refractory linings for the end walls, side walls, and top are installed. The fabrication diagram of the radiation section enclosure is shown in Figure 3. The burners, air preheaters, and bottom refractory linings that affect transportation are installed on-site at the facility before construction proceeds. 2) After the radiation chamber is in place, transport brackets are installed on both sides; the furnace bottom brackets between axis A-B and axis C-D in the middle are fabricated and installed together with the chamber before the temporary foundation for the radiation chamber body is in place. 3) The convection section includes the desulfurization and denitrification (SCR) modules along with their internal components; there are a total of 5 box-type modules. Professional and qualified manufacturers produce the tube bundles and wall panels as integrated units, which are then delivered and installed above the transition section (axis B to axis C). 4) The outer frame of the convection section is fabricated as separate modules on the left and right sides at ground level; during this process, a first-stage quench cooler is installed horizontally (4 SLE units on each side). The frames on both sides are then raised and combined to form one large module equipped with 8 first-stage quench heat exchangers and platform facilities, which is lifted into place in one go. The fabrication diagram for the convection section frame is shown in Figure 4.
5) The flue ducts and smoke collectors for axes B and C are installed at ground level; the lining is applied in a horizontal position using castable material. Once the lining is completed, an internal frame is formed, and the outer frame sections on both sides, together with the internal frame, constitute one module. After the furnace top platform was completed, the steam drum was lifted into place, and the entire large module was lifted at once above the convection section. The fabrication illustration for the smoke collector drum platform section is shown in Figure 5. 6) Ladder platforms, personal protective equipment, lighting fixtures, electrical cable trays, and other process pipelines are lifted into place together with the main module, without any further installation required. The installation of the instrument cable is the same as above. 7) The rising and falling pipes, the secondary quench heat exchanger, the tertiary quench heat exchanger, and the auxiliary platform are installed separately. 8) Due to transportation constraints, the chimney and bottom burners can be installed after being placed in place on site. 9) Once all the refractory linings inside the furnace have been installed (except at the bottom) and protective measures have been taken, they are lifted together with the furnace and transported alongside it.