Continuous gas generator with a pre-drying chamber for gasified raw materials

Abstract

This utility model relates to gasifiers for the gasification of solid fuels. The continuous gasifier enables the thermochemical conversion of the organic portion of solid fuel into gas suitable for subsequent convenient and beneficial use. The resulting gas can be used as fuel for boilers, in gas turbine combustion chambers, for subsequent processing into target marketable products, and more. The utility model proposes a drying chamber design installed upstream of heated channel sections, which will intensify the heating and drying process of the feedstock, increasing the efficiency of coolant use and reducing the overall dimensions of the gasifier. A drying chamber is located upstream of the feed hopper for crushed gasified feedstock into the heated channels. Flue gas exiting the outer jacket of the heated channels at a temperature of 200-300°C is fed into the drying chamber.In the drying chamber, the feedstock to be gasified is heated by direct contact with the flue gas, and the water evaporated from the feedstock is discharged along with the flue gas. Next, the feedstock, heated to 150-200°C, enters heated channels, where the gasification process occurs. This design significantly reduces the required length of the heated channels, reducing the overall dimensions of the gasifier and allowing more efficient use of the flue gas heat by directly heating the feedstock in the drying chamber, which is more efficient than heating through the channel walls. 1 fig.

Description

[0001] The utility model relates to gas generators for gasification of solid fuels.

[0002] Gasification of solid fuels refers to the thermochemical process of converting the organic portion of a solid fuel into a gas suitable for subsequent convenient and useful use. The resulting gas can be used as fuel for boilers, in gas turbine combustion chambers, and for subsequent processing into target marketable products, etc.

[0003] The gasification process is traditionally implemented in various types of gasifiers. The most widely used are shaft-type gasifiers, in which the gasified feedstock is loaded from above through a loading hopper and, as it gasifies, descends downward, passing through drying, pyrolysis, and combustion zones. The necessary heat for the gasification process is supplied by burning a portion of the gasified feedstock. However, traditionally used gasifiers have a number of significant drawbacks: they require large capital investments and significant operating costs, and they do not produce gas with a high calorific value and a low cost price. During operation, such gasifiers emit significant amounts of harmful substances into the environment. Traditionally used gasifiers typically operate cyclically, with variable feeds of oxidizer and gasifying agent, such as water vapor.

[0004] One of the promising designs of a gas generator, which is largely free from the above-mentioned disadvantages, is a continuous gas generator for gasification of solid fuels according to Russian Federation Patent for Invention No. 2825949 dated 07.02.2024 (adopted as a prototype). The specified design of the gas generator comprises: a hopper for receiving crushed gasified raw materials; heated channels; a chamber for receiving the resulting gas and a slag unloading chamber; as well as units for preparing feedwater, generating and superheating water vapor used as a gasifying agent, obtaining a coolant for heating the gasifying agent and heated through the channel walls, and recovering the heat of the exhaust flue gas.

[0005] The heated channels consist of individual sections connected by flanges at their ends. A device for transporting the gasified feedstock from the raw material receiving bin to the slag unloading chamber is installed within the sections. The channel sections, located between the raw material receiving bin and the resulting gas receiving chamber, are equipped with a device for feeding the gasifying agent into the gasification zone. Each section is rigidly attached to a common frame and has its own device for compensating for thermal expansion of the material from which the sections are made. Each channel has an outer jacket, creating a space between the outer walls of the sections and the jacket for the passage of the coolant.

[0006] The disadvantage of the gas generator according to the specified patent is the insufficient efficiency of using the heat of the coolant - flue gas, with the help of which heat is supplied to the raw material through the walls of the heated channels for the gasification process.

[0007] Supplying the required amount of heat to the feedstock through the walls of the heated channels requires a significant heat-transfer surface area and the residence time of the gasified feedstock within the heated channels. The gasification process itself begins only after the feedstock temperature reaches at least 250-400°C. Before this temperature, only the feedstock is heated and the water contained in the feedstock evaporates, thereby drying the feedstock. Water evaporation is known to significantly exceed the heating process in terms of heat consumption, and the water content in some feedstocks, such as wood, can reach 50% or more of the feedstock's mass. As a result, the first sections of the gasifier heat and dry the feedstock without gasifying it, using the heat from the flue gas, which is supplied to the feedstock through the walls of the heated channels. This process can be performed more efficiently.

[0008] The objective of this utility model is to develop a design for a drying chamber installed in front of heated channel sections, which will intensify the process of heating and drying raw materials, increasing the efficiency of using the coolant and reducing the overall dimensions of the gas generator.

[0009] The problem is solved in the utility model as follows: a drying chamber is placed before the feed hopper for crushed gasified raw materials into heated channels. Flue gas at a temperature of 200-300°C, exiting the outer jacket of the heated channels, is fed into the drying chamber. In the drying chamber, the gasified raw material is heated by direct contact with the flue gas, and the water evaporated from the raw material is discharged along with the flue gas. The raw material, heated to a temperature of 150-200°C, then enters the heated channels, where it undergoes gasification.

[0010] This design allows for a significant reduction in the required length of the heated channels, which reduces the overall dimensions of the gas generator and allows for more efficient use of the heat from the flue gas by directly heating the raw material in the drying chamber, which is more efficient than heating through the channel wall.

[0011] Thus, the continuous gasifier comprises: a hopper for receiving crushed gasifiable raw materials, heated channels, a chamber for receiving the produced gas and a slag unloading chamber; each heated channel consists of separate sections connected to each other at the ends by flanges and fixed on a common frame; a device for moving the gasifiable raw materials from the hopper for receiving raw materials to the slag unloading chamber is installed inside the sections; each channel has an outer jacket with pipes for inlet and outlet of the coolant; a drying chamber is located in front of the hopper for feeding crushed gasifiable raw materials into the heated channels, with pipes for inlet and outlet of the coolant, wherein the pipe for inlet of the coolant into the drying chamber is connected to the pipe for outlet of the coolant from the outer jacket of the heated channels.

[0012] The utility model is further explained by a specific example of its implementation and the attached drawing Fig. 1, which schematically depicts a longitudinal section of a continuous gas generator.

[0013] The continuous gas generator includes a drying chamber 1 with a hopper 2 installed in front of the hopper 3, to which heated channels 4 consisting of sections 5 are adjacent. On the opposite side from the hopper 3, channels 4 are adjacent to a chamber 6 for receiving the produced gas, behind which a slag unloading chamber 7 is installed. The drying chamber 1, sections 5 of the heated channels 4 and chambers 6 and 7 are rigidly fixed on a common frame 8. Sections 5 of the heated channels 4 are connected to each other by means of flanges 9, to compensate for the thermal expansion of the metal, a compensator 10 is provided on each section 5. A device 11 is installed inside the channels 4 for moving the gasified raw material from the hopper 3 through sections 5 and chamber 6 to the slag unloading chamber 7. A device 12 is installed inside the drying chamber 1 for moving the gasified raw material through the drying chamber 1.

[0014] The crushed gasifiable feedstock is fed via line 13 to hopper 2 and passes through drying chamber 1, being moved by device 12. Drying chamber 1 is installed at an inclination of 5-35° to the horizontal plane. After drying chamber 1, the gasifiable feedstock enters hopper 3 and is then moved by device 11 through heated channels 4 and chamber 6 to slag discharge chamber 7. During this process, the feedstock is gasified, the resulting gas is removed from chamber 6 via line 14, and the sludge is discharged from chamber 7 via line 15.

[0015] Heated channels 4 are located inside the outer jacket 16, into which a heat carrier is supplied via line 17 and discharged via line 18 for heating the channels 4. The heat carrier leaving the jacket 16 is supplied to the branch pipe 19 of the drying chamber 1. In the drying chamber 1, the raw material is heated by direct contact with the heat carrier, and the water evaporated from the raw material is carried away together with the heat carrier discharged through branch pipe 20 via line 21.

Claims

A continuous gas generator comprising a hopper for receiving crushed gasifiable raw materials, heated channels, a chamber for receiving the resulting gas, and a slag unloading chamber; each heated channel consists of separate sections connected to each other at the ends by flanges and secured to a common frame; a device for moving the gasifiable raw materials from the hopper for receiving raw materials to the slag unloading chamber is installed inside the sections; each channel has an outer jacket with pipes for supplying and removing a coolant, characterized in that a drying chamber with pipes for supplying and removing a coolant is located in front of the hopper for feeding crushed gasifiable raw materials to the heated channels, wherein the pipe for supplying a coolant to the drying chamber is connected to the pipe for removing a coolant from the outer jacket of the heated channels.

Images