3. Structural characteristics of HM5Q new two-stage dry distillation gasifier

 The difference between the new two-stage dry distillation gasifier and the traditional two-stage gasifier lies in the removal of the lower gas outlet. All the gas produced inside the gasifier is discharged out of the gas outlet at the top of the gasifier.

 2. The gas production process of the new two-stage dry distillation gasifier: Air and steam, serving as gasification agents, are blown into the furnace from the bottom. Under high temperature conditions, they undergo oxidation-reduction reactions with the coal entering the gasification section, which has a semi-coke nature, forming gas primarily composed of CO and H2. The gas moves upward into the dry distillation section, where it directly contacts the slowly moving downwards coal for gasification, transferring its heat directly to the coal for gasification, thereby dry distilling and drying the coal. Simultaneously, a portion of dry distillation gas, primarily composed of high-calorific value gases such as alkanes, is produced. This upward-moving gas, along with the dry distillation gas produced during the dry distillation process, is discharged through the gas outlet.

3. The new two-stage dry distillation gasifier produces tar with low density, moderate viscosity, and good fluidity. After dust removal and decoking treatment, the gas purification degree of the gasifier is high. The gasifier is easy to operate and the gas purification process is simple and reasonable. It is a type of furnace more suitable for gasifying volatile and high moisture coal. The gasification technology of the new two-stage dry distillation gasifier not only absorbs the characteristics of high calorific value dry distillation gas and low temperature light tar that can be produced during coal dry distillation, but also realizes the characteristics of generating more gasified coal gas during complete coal gasification. It integrates the advantages of both into the same gasifier.

4. Performance advantages of HM5Q new two-stage dry distillation gasifier

A. High calorific value of gas

  The coal material undergoes thorough carbonization within the carbonization section, resulting in a gas calorific value generally ≥1500Kcal/Nm3. When compared with the same type of coal gasification, the calorific value of the carbonization furnace is about 15% higher than that of a single-stage furnace, and about 3-5% higher than that of a conventional two-stage furnace.

B. The amount of pulverized coal carried by the gas discharged from the furnace is small

Ø Realize full material layer operation in the furnace through the "hydraulic probe-type coal level automatic detector" - reduce dust emission during coal feeding due to height difference

  The hydraulic probe-type automatic coal level detector, through PLC interlocking with the coal feeder, maintains a full material layer inside the furnace at all times, ensuring that there are no empty layers and preventing coal dust from being carried out of the furnace with the gas during coal feeding.

Adopting a "single outlet structure" - to avoid the carry-out of coal dust caused by flame detection, rod driving, and thermal explosion

  Due to the absence of a lower gas outlet, the thick carbonization layer filters out the thermally exploded coal powder during gasification. Therefore, gas generators with a carbonization section are significantly superior to two-stage generators in terms of reducing ash carried by the gas. This is because most of the ash generated by thermal explosion of coal material in the gasification section and the ash stirred up during flame probing and rod driving in two-stage generators is carried to the downstream system along with the lower gas. However, in gas generators with a carbonization section, these two parts of ash are mostly deposited after being filtered through the thick material layer, resulting in a significant coal saving effect compared to two-stage generators.

Set up a "fixed quantity spraying and dust suppression system on the furnace top" - to reduce the carry-out amount of fine coal powder in the gas discharged from the furnace

  The top of the gasifier is equipped with a quantitative spray dust suppression system. This system, through a quantitative water supply device, evenly sprays process wastewater such as phenolic water onto the surface of the coal material entering the gasifier. This ensures that the finer coal powder on the surface of the coal material adheres to the coal blocks, preventing it from being carried out of the gasifier by the gas. Consequently, this reduces the dust content in the gas produced by the gasifier. This system is interlocked with the coal feeding mechanism, automatically initiating and performing quantitative spraying.

C. Good tar properties

  Through actual operation and sampling inspection of the by-product tar from the HM5Q new two-stage dry distillation gasifier, it has been found that the tar produced by this gasifier has low ash content, low density, and low viscosity. Its performance indicators are superior to those of tar produced by one-stage and two-stage gasifiers.

The gas produced in the gasification section of the new two-stage dry distillation gasifier enters the dry distillation section, so the heat provided to the coal material by the gasifier is approximately 2-3 times that of a two-stage gasifier, resulting in an increased tar yield. When coal is gasified in a two-stage gasifier, the tar yield as a by-product is generally 4-5%. The tar yield in a dry distillation gasifier is 50-60% higher than that in a two-stage gasifier.

D. High thermal efficiency

  This furnace utilizes the sensible heat of the gas produced in the gasification section to preheat, dry, and carbonize the coal material entering the furnace, thus saving heat consumption for heating cold semi-coke and achieving a thermal efficiency 3-5% higher than that of a two-stage furnace.

E. High gasification intensity

  Due to the relatively thick coal layer inside the gasifier and the high-temperature semi-coke entering the gasification section, it is beneficial to enhance the gasification intensity of the gasifier.

F. Easy to operate

  In the operation of a two-stage gasifier, the regulation of gas flow in the upper and lower stages is crucial. If the upward flow of gas produced in the gasification stage is too small (externally manifested as low gas flow in the upper stage), the heat for dry distillation will be insufficient, leading to incomplete coal dry distillation and inevitably resulting in a large amount of high-temperature cracked tar in the gas from the lower stage. To avoid this situation, it is necessary to add a high-temperature gas regulating valve at the gas outlet of the lower stage in the process configuration to properly regulate the gas flow in both stages. This increases the complexity of the gasifier operation. However, the new two-stage dry distillation gasifier has only one gas outlet, eliminating the need for such regulation. Moreover, all the gas produced in the gasification stage participates in the dry distillation, providing heat for it and ensuring more complete dry distillation of coal material.