Regarding the review comments on the feasibility study report, I wonder what everyone thinks of the depth of this review? What aspect is missing?

Thread Content

The last edit to this post was made by 328104062 on 2015-12-8 at 22:37. The review comments for each section are as follows: 5. Process technology plan and equipment plan: 1. In 5.2 Process flow overview, there is a section on raw material washing; the main purpose of this is to protect the catalyst； It is recommended to eliminate the washing process and, by referring to certain refining units, install light gasoline purifiers (one in operation and one as a backup), equipped with the same resin catalysts as those used in the reactors. The reasons are as follows: (1) With washing, the raw material can only pass through once to become the product; the product cannot be recycled back to the raw material tank, otherwise the washing water will become unsuitable, affecting the wastewater treatment plant ； In this way, after the feed to the device is cut off, circulation cannot be established; instead, the feed must be stopped and methanol used for cooling, which results in large fluctuations and hinders recovery of production. (2) After washing, the raw material may contain a small amount of water, especially when the operation is unstable; this can lead to the loss of sulfonic acid groups (the rate of loss increases at high temperatures), which hinders the maintenance of catalyst activity and also increases the risk of corrosion in the system. (3) After washing, the wastewater treatment load increases; especially in the presence of methanol, the COD value for 1% methanol can exceed 10,000 ； Preventing freezing of water pipelines in winter is also a problem ； To the best of our knowledge, neither So-and-so nor So-and-so Factory uses water washing, and their conversion rates are both high (over 90%). There are no specific specifications set for basic nitrogen compounds such as acetonitrile and propionitrile in light gasoline. 2. Table 5.6.1 shows the water consumption for supply and drainage; the water usage in the demineralization tower is 3 t/h, which differs from 15 t/h stated in 10.4. 3. Regarding the utilization of condensate water in the plant: the methanol recovery tower and a certain distillation tower use steam as a heat source, with a steam consumption of 16 tons per hour (with minimal fluctuations when operation is stable). This steam is pumped outside the plant; therefore, it is possible to utilize the heat contained in the condensate water (16 tons) as a heat source for the feed preheater, thereby reducing the amount of heat transfer fluid needed (as heat transfer fluid is already scarce in winter). 4. In a situation where there is an excess of steam throughout the plant (3.5 MPa, with a surplus of 337.7 t/h) ； With 57.72 t/h of excess steam at 1.0 MPa, it is recommended to consider using steam as the heat source for So-and-so. 5. Table 5.7-1: Specifications of major equipment; it is recommended to increase the number of methanol wastewater pumps to 2 ； The reasons are as follows: (1) There are no underground sludge oil tanks inside the device; all sludge oil and methanol go into the sludge methanol tank, from where they are pumped into the extraction tower using a sludge methanol pump. It is recommended to have one spare pump for this purpose. When the catalyst is soaked in methanol for dehydration, this pump is of utmost importance, and it is also used for liquid removal on a daily basis. 6. Automatic Control and Information Engineering 1. In section 6.1.4 on the control room, it is required that at least one MES operation station be installed in the control room to facilitate daily queries and report preparation by operators (such as material balance reports and stability rate reports) ； It is necessary to add SIS operation stations and auxiliary control panels for a certain device (if shared with the gasoline hydrogenation unit, please specify). 9.1 Storage and Transportation 1. In Table 9.1-1, the main parameters of the storage and transportation system, the flow rate of the methanol feed pump is Q=6 m3/h. For a plant that consumes 42,600 tons of methanol per year, this value is relatively low (at another factory, Q=11 m3/h); it is recommended to increase this flow rate. 2. There are doubts regarding the gasoline storage and transportation system in 9.4.2 – no changes are required. (2) The vapor pressure of certain gasoline is 104 KPa, which is relatively high; as a result, it cannot be stored in tanks on its own, yet it still constitutes a qualified product. (3) If there are problems with the hydrodesulfurization unit of the gasoline hydrogenation plant, such as unsatisfactory sulfur content or corrosion issues, then if certain type of gasoline is mixed with heavy gasoline in the storage tank, that type of gasoline cannot be fed into the hydrogenation plant for reprocessing; the factory in question strictly prohibits such gasoline from being used in the hydrogenation plant for reprocessing. (4) Therefore, it is necessary to consider the situation where the pre-hydrogenation system is operating properly and everything else is functioning normally; in cases where hydrodesulfurization does not meet the required standards, there are issues related to the storage of certain types of gasoline. The substandard hydrogenated heavy gasoline produced by that factory can be stored in intermediate material tanks, while that particular type of gasoline can be stored in separate component tanks. There are 3 such intermediate material tanks and 3 component tanks, with each having a capacity of 5,000 cubic meters. 10.4 Heating and Air Supply 1. For the water supply at the bottom of the methanol extraction tower, it is recommended not to use deoxygenated water; instead, the condensed water generated within the plant should be used (16 tons of condensed water are produced in the plant). The reasons for this are as follows: (1) The water supply point is located at the inlet of the pump at the bottom of the recovery tower, where the temperature is around 130°C. If the temperature of the make-up demineralized water is at room temperature, fluctuations will occur during water replenishment. (2) This is not a continuous water supply; installing dedicated demineralized water lines is not conducive to preventing freezing in winter. (3) When the condensate water fully meets the requirements for water used in extraction and recovery (with the main purpose being to replace the acidic substances obtained through extraction and recovery), it enables the use of such water, which helps to save energy and reduce costs as well as lower investment requirements. 10.7 Laboratory Analysis 1. Table 10.7-1 lists the analysis items, methods, and frequency requirements; the pH value of the extraction water and the analysis of iron ions have been added to facilitate the monitoring of corrosion. The frequency can be once a month or once a week. 2. In the analysis of light gasoline, the determination of diene content has been added; a certain factory requires that this value be less than 300 PPM (for domestically produced catalysts). 11-12: Energy conservation and water utilization. 1. Under the water-saving measures in 12.2, it is stated that \"4) The cooling water for pumps and the cooling water for pump bearing housings should all be designed as circulating water.\" Considering the problem of scaling in circulating water, it is recommended to use deionized water in combination with a water softening system to cool components such as pump bearing housings and seal units. Manager Discussion Group