Discussion on single furnace production of two-sta

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Discussion on the production of single furnace with two-stage furnace *

classification No. tu996 tq5481 foreword our factory uses a two-stage water gas furnace with a diameter of 3.3 meters to produce gas. The characteristics of this furnace type are less investment, small floor area, short process flow, simple and convenient operation, good environmental protection, which is more suitable for coal gasification in small and medium-sized cities and as a peak shaving gas source in large cities

our factory has three sets of two-stage furnaces, with a production capacity of (60 ~ 80) KM3/d. There are only more than 20000 gas users in the city, and the daily gas consumption is only 30 KM3/d. The two-stage furnace is in the stewing state for a long time, which will inevitably cause the temperature of the heater and combustion chamber to drop more, so that when the blast gas enters the equipment again, it will not burn below its ignition point, and even lead to explosion accidents, damage to production facilities and blockage of waste heat boiler fire pipes, resulting in shutdown, In this way, there is not enough process steam to meet the needs of production. Gas production must rely on two fast loading boilers to supply steam, causing great waste, and the thermal efficiency and gasification rate of the gas production system are greatly reduced. The gas production consumes 1.25t/km3 lump coal gas, and the boiler consumes 0.6t/km3 fuel coal gas. It is of great significance to carry out technical transformation of single furnace production, reduce energy consumption, and improve gas heating efficiency and gasification rate. 2 process overview from the perspective of process design, three sets of gasifiers operate in parallel, and various process technical parameters are the most economical. The process flow is shown in Figure 1. The two-stage gasifier is an intermittent gas making method, with a cycle of four minutes. The following is a brief introduction to the process flow chart of the main stages. 1. Dn3.3m two-stage gasifier process flow (1) blast stage: air is blown into the gasifier through the grate, providing energy in the material layer, producing low calorific value blast waste gas, indirectly heating the fuel coal along the fire path of the retort section, and passing through the cyclone dust collector, heat increaser and fixer, And the secondary air is introduced at the top of the heat exchanger to make some combustible components burn, and the heat is stored in the lattice brick. Then the waste gas enters the combustion chamber, and then the tertiary air is introduced. It is not conducive to the long-term preservation of components by completely burning the combustible components in the waste gas. The burned waste gas passes through the waste heat pot to facilitate the user to conduct secondary data processing; The furnace recovers heat and discharges it into the atmosphere. The steam produced by the waste heat boiler is used in the gas making process

(2) up blowing gas: the process steam is introduced through the bottom of the gasifier and enters the reaction layer to react with the hot coke to generate water gas. The water gas is exported from the carbonization chamber through the top and sent to the purification system through the up blowing collector

(3) down blowing gas: the process steam is introduced from the top of the holder and reversely passes through the holder and the heat increaser, in which the saturated steam is overheated, and then passes through the cyclone dust collector and enters the reaction layer of the gasifier downward from the fire path of the upper retort section of the gasifier. The generated water gas is exported from the bottom outlet and sent to the subsequent purification system through the down blowing collector

in addition, the first blowing and the second blowing in the gas making process are two auxiliary processes to improve the quality of gas and ensure safety, which will not be repeated here

during the parallel operation of the three boilers (combustion chamber and waste heat boiler are public equipment), the three sets of boiler groups should be staggered in a cycle, so that the waste heat boiler can work at any time, and can produce enough steam at any time. After being balanced in the steam accumulator, it can be used for process production. This can maximize the thermal efficiency of the gas producer, and also greatly improve the gasification rate. 3. Solutions for single furnace production we believe that in the process of single furnace production, trying to use the blast gas to burn it in the heat exchanger and combustion chamber is a good way to solve the energy saving and consumption reduction of single furnace production. The reflux gas is used with the corresponding air (which can be adjusted by valves to achieve the best combustion conditions) to pass into the heat increaser and holder, and the normally open torch is installed in it. When the furnace is stewed, its temperature can be adjusted to 600 ~ 700 ℃, so as to ensure the normal operation of the heat increaser, holder and combustion chamber in the case of single furnace production, greatly improve the thermal efficiency and gasification rate of production, and save energy. See Figure 2 for the normally burning flare

Table 1 shows the consumption of raw coal in our plant from January to December 1995 (after the Changming torch). Table 1 table of raw coal consumption for each month in 1995 item 12345678912 gas production m gas coal t boiler coal we should actively recycle waste plastics and make printing materials tkm3 gas

consumption of lump coal 1.00.970.990.980.971.011.02km3 gas

consumption of fuel coal 0.300.310. according to the data in table 1, consumption of lump coal 1.0 t/km3 gas, Source of consumption picture: danimerscientific fuel coal 0.23 t/km3 gas. Obviously, a lot of energy can be saved after lighting the Changming torch. Figure 3 shows the relationship between the change of gas production and the raw materials consumed. Figure 2 Changming flare diagram Figure 3 Relationship between different gas production and comprehensive coal consumption. It can be seen that with the increase of gas production, there is a large gap between the comprehensive coal consumption of the two. In other words, after lighting the Changming torch, the unit consumption of coal can be greatly reduced and a lot of money and energy can be saved. Therefore, it is very necessary and feasible to carry out technological transformation on the single boiler operation of dn3.3m two-stage water gas furnace

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