How is the dosage of coal slurry to be added determined?
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How is the dosage for preparing coal slurry determined? When we prepare the slurry, we often encounter problems such as slurry leakage or failure to produce slurry at all. The specified viscosity range is 300–1000, but in each case it ends up being higher than 1000, sometimes even several thousand; yet the concentration remains acceptable.
It is generally considered to be around 0.5% based on dry coal. There are no exact figures; coal quality varies, and the types and amounts of additives also differ! There is no best one; only the additive that is most suitable for that specific type of coal. Most first require laboratory evaluation!
Agree with what was said on the second floor; we can learn from other manufacturers
Is there any theoretical guidance before the experimental testing? Or it can be roughly estimated structurally. It seems that there is a lot of research being done on additives these days as well.
Let me add that additive technology is already a mature technology in China, with a wide range of different types available. The most commonly used ones are those top-tier products, which are typically chosen as the preferred materials and are specifically designed for different types of coal. With experience, one can avoid many pitfalls; it’s advisable to seek advice from other manufacturers, as there are no barriers to knowledge sharing among them – they all learn from each other!
There are various types of additives; sodium lignosulfonate, which is derived from waste pulp, is commonly used. The amount used is 0.5%–1% of the coal on a dry basis. There are many reasons for slurry leakage, and it is closely related to the quality of the coal. Generally, the amount of additive required is determined during the design phase, based on the coal quality analysis reports provided by the manufacturer. Therefore, during operation, as long as there are no problems with the additive pump and the coal quality does not change, the dosage of the additive remains unchanged. Slurry leakage is often caused by high concentrations, clogged screens, and an excessive amount of coarse particles; it is also related to the operating time of the rod mill, the amount of steel rods used, and the degree of wear. Under normal operating conditions, the concentration cannot reach the designed value; if operations are not carried out according to the designed values, slurry leakage will definitely occur.
The concentration of additives is generally selected and determined through laboratory pulping tests. Once the type of coal to be used in the facility is determined, tests are carried out to assess its pulping properties as well as its suitability for gasification. Only after such performance evaluations can the concentrations of additives and their types used in industrial pulping processes be determined, which in turn enables the establishment of the basic data needed for engineering design. Generally, when the type of coal changes, there is a period of instability in the facility’s operation. To avoid this, it is advisable to consult the most authoritative coal evaluation institution in China – the Northwest Research Institute of Chemical Industry – before making any changes in the type of coal used, thereby avoiding unnecessary complications
There is no formula for calculating the amount of additive; it can only be determined through experimentation. Many factors influence the amount of water-coal slurry that can be used. Generally, a viscosity below 1000 is not a problem. It is recommended to conduct experiments
Generally, the viscosity of water-coal slurry is required to be no more than 1000 CP, but 1200 CP is also acceptable. Our factory uses Shenfu coal, which is a type of coal that is quite difficult to process into slurry. We employ additives provided by Nanjing University, and they prove to be effective; the dosage is 1.5 per thousand of the amount of coal slurry used. The viscosity is less than 1200 CP, while the concentration ranges between 60–62%.
As determined through laboratory pulping performance evaluation tests, the general addition amount is from one thousandth to one thousandth five (for coal-based materials). This has a lot to do with the quality of coal; give it a try! Practical experience is the most reliable!
There are many types of additives, each with different components; however, the typical addition amount is 1% to 1.5% of the theoretical amount based on the amount of raw coal, and these additives are added to the coal slurry. After the slurry is prepared, adjustments are made depending on its viscosity