Discussion on desulfurization waste liquid

1. Coal blending； 2. Coal blending after concentration (reduction in volume) ； 3. Prepare coal blend for salt production ； 4. Produce refined salt – it is still estimated that coal blending will be used for now ；

In the case of ammonia-based desulfurization, coal blending, salt extraction, and acid production are the options available. However, the first two methods are only temporary solutions; coal blending is used by most coking plants. As for salt extraction, it cannot be carried out on a continuous basis due to issues with purity levels. If acid is produced using desulfurization wastewater and sulfur foam (through either dry or wet combustion processes), it becomes possible to recycle the by-products salts. There are already industrial facilities for these two acid production methods, and their operation is generally reliable. It is recommended that companies go and investigate these acid production processes in detail. Another method is the technology of producing ammonium sulfate by acidifying desulfurization wastewater with concentrated sulfuric acid (Tianjin Carbon-1), but this technology has not yet been industrialized. If the sodium-based desulfurization process is used, then only the salt extraction process can be employed for treatment.

This post was last edited by dmz329227 on 2019-4-18 at 10:11. There are now quite a number of companies in China that produce acids; there are also three manufacturers of process packages (as far as I know). 1. Nanjing Hailu； 2. Xinan Industry in Pingxiang, Jiangxi ； 3. Jiaonai Institute: Each of these options has its advantages and disadvantages. It is recommended to consult the actual manufacturers who will use the products, rather than relying solely on the opinions and statements of the suppliers of the process packages. The actual projects for producing acid from desulfurization waste liquids that I am aware of are as follows: 1. Shandong Jinneng Technology (it seems to be a joint effort by Hailu and Jiaonai Institute, or it might be carried out by Jiaonai Institute alone); 2. Sichuan Chuanwei Group Co., Ltd. (the first company to produce acid, but its coking operations have been halted, so acid production has also stopped); 3. Hebei Bohai Coal Coking Co., Ltd. (Cangzhou China Railway’s facility is already in operation, while Bohai Coking is under construction in Fengnan Heiyanzhi); 4. Qian’an Jiujiang Coal Storage and Transportation Co., Ltd. (already in operation); 5. Tangshan Rongyi Coking and Gas Production Co., Ltd. (already in operation); 6. Tangshan Hong’ao Coking (seems not yet completed); 7. Shanxi Xiaoyi Pengfei (under construction, using technology provided by Xinan Industry, with Sanju Environmental Protection acting as the general contractor); 8. Jiuquan Iron and Steel (construction is in progress); 9. Inner Mongolia Hengkun Chemicals (construction is in progress). Key issues to consider: 1. If dry-process acid production is used, how can dust pollution be addressed? (It is necessary to conduct research with the manufacturers.) ； 2. How is the on-site leakage? What is the smell like at site S02? ； 3. What is the service life of the process equipment, what is the level of corrosion, and how often does it need to be replaced? ； 4. Downtime for maintenance (as far as I know, maintenance is required within no more than 3 months) ； 5. What is the quality of the product? (Many products are labeled as 98% acid, but actually contain a high amount of impurities.) ； 6. If acid is produced by dry process, how can the coking problem in the incinerator be solved or alleviated? ； 7. If acid is produced by the wet process, how can equipment corrosion be reduced at high temperatures, and what is the situation regarding corrosion of the furnace tubes in incinerators? ； 8. How much coking occurs in the incinerator, and how should this coking be dealt with (is landfilling the only option? ? ? ) In fact, for the current treatment of desulfurization waste liquids, aside from traditional methods such as coal blending, crude salt purification, and refined salt production, the option of using it for acid production is the most common; however, it is necessary to consider factors such as the cost per ton of acid produced and environmental considerations at the site to determine whether this approach is appropriate ； Additionally, under consideration at present is the scheme of reusing HPF desulfurization agents in the production of ammonium sulfate from ammonia-based desulfurization wastewater at Tianjin Carbon One (currently in pilot phase); particular attention is being given to the technology for producing sodium pyrosulfite from desulfurization wastewater at Tianjin HuiNeng LangTian.

New catalyst, by-product salts stable. complexed iron

Building 5# has made it clear that Qian’an and Rongyi in Hebei use the Pingxiang technology. The conditions at Qian’an’s site are not very good, while Rongyi made significant improvements to the existing problems during the design phase (including the transportation of slag powder and the incinerators). Hongao also replaced and improved the drying equipment. Overall, the operating costs are much lower compared to those of the wet process for acid production, and the operation is also simpler； However, there are still many areas that need improvement and refinement (such as the treatment of dried exhaust gases and the storage of dry materials). Baosteel has a relatively stable operation in the wet acid production process; its facilities are clean, and the operation is reliable and stable. However, many of its equipment is imported, and the process for desulfurizing gas also differs. Generally speaking, the owner needs to conduct thorough research before deciding on which process technology package to use; each option has its advantages and disadvantages, and there is no perfectly ideal or comprehensive process package for implementing a project.

It is appropriate to learn about the methods for acid suppression in the relevant operational environments; for existing installations, some can still be modified

At present, the process of producing acid from sulfur and desulfurization wastewater is the best method for ammonia-based desulfurization; it enables complete treatment of the desulfurization wastewater and also allows for the production of sulfuric acid. At present, the wet-fed acid production process at Jiaonai Institute has been improved and refined through several iterations, and it is now quite mature. All of the equipment used in this process is domestically produced, with multiple factories already in operation. The original poster can go and find out.