RU2238962C1 - Gaseous fuel generation process - Google Patents

Abstract

FIELD: alternative fuels.

SUBSTANCE: gaseous fuel for heat, power, and liquid fuel production is obtained by gasifying wood raw material at 900-1100^оС with water steam, wood being heated for 9 to 35 min and consumption of steam being at least 0.7 kg per 1 kg absolutely dry wood. Generated gas is characterized by heat capacity 11-12 mJ/m³ and energy production at least 80% on heat capacity of starting wood.

EFFECT: enhanced process efficiency.

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Description

The invention relates to the field of producing gaseous fuels from wood raw materials and can be used to produce heat, electricity and liquid fuel.

Known methods for producing gaseous fuels from wood by gasification. The process is as follows. The wood is heated to a temperature of 900-1100 ° C, while at first it is dried, then decomposition with the formation of vapors of organic substances, gases and carbonizate (coal). The resulting carbonizate is reacted with a gasification agent (air, steam-air mixture, oxygen, carbon dioxide), which is fed to the hot carbonizate. The resulting gases along with the decomposition gases of wood make up gaseous fuel [1, 2]. [1. Geletukha G.G., Zheleznaya G.A. Overview of biomass gasification technologies // Ecotechnologies and Resource Saving - 1998, - No. 2. - p.21-30].

There are methods of gasification of wood with the upward movement of steam and gas, countercurrent movement of the wood (direct process), and downward flow to the movement of wood (reversed process).

Closest to the proposed technical essence and the achieved result is a method of producing gaseous fuel with a downward movement of steam and gas, including heating wood chips to a temperature of 900-1100 ° C and processing the resulting carbonizate with a steam-air mixture [2. Lyamin V.A. Gasification of wood. // - M. - From "Forest industry" - 1967 - p. 18]. The duration of the process is 3 hours. The output of gaseous fuel is 1.6 m ³ per kg of absolutely dry wood (a.s.d.), the calorific value is 7 MJ / m ³ . The achieved energy yield of 11.3 MJ / kg a.s.d. 59.7% of the calorific value of wood (18.9 MJ / kg a.s.d.).

The disadvantage is the low calorific value of gaseous fuel and energy output.

The aim of the invention is to increase the calorific value of gaseous fuel to a value of not less than 11.7 MJ / m ³ while increasing the energy output to 15.1 MJ / kg a.s.d. (not less than 80% of the calorific value of wood).

The goal is achieved by the described method, including heating wood raw materials to a temperature of 900-1100 ° C for 9-35 minutes and subsequent processing of the resulting carbonizate with water vapor in an amount of not less than 0.7 kg / kg a.s.d. at the indicated temperature, for 35-50 minutes.

The difference between the method is that the wood is heated for 9-35 minutes.

Another difference is that the steam flow rate is at least 0.7 kg / kg a.s.d.

The method is as follows.

Wood chips are heated to a temperature of 900-1100 ° C for 9-35 minutes, water vapor is fed to the resulting carbonizate in an amount of at least 0.7 kg / kg a.s. The gas resulting from the interaction of the carbonizate and water vapor, combined with the decomposition vapor-woods of wood formed during its heating, is a gaseous fuel.

Example 1

Wood chips with a particle size of 5-15 mm, a moisture content of 10% and a mass of 1 kg are heated to a temperature of 1000 ° C for 24 minutes. Water vapor is fed to the resulting carbonizate in an amount of 0.8 kg / kg a.s.d. Combined from the decomposition of wood chips during heating and obtained by the interaction of the carbonizate with water vapor, the vapor gas enters the refrigerator-condenser, where the vapor condenses and the gases are cooled.

The resulting gaseous fuel has the following composition,%: CO ₂ - 13.7; CH ₄ - 5.8; СО - 37.5; H ₂ - 42.9; CnHm -0.1.

Its calorific value is 11.5 MJ / kg a.s.d., the output is 1.37 m ³ / kg a.s.d.

The energy output is 15.8 MJ / kg, i.e. 83.4% of the calorific value of wood.

Other examples are tabulated. The experiments were conducted at a steam flow rate of 0.8-0.9 kg / kg a.s.d.

When carrying out the process according to the proposed method with a wood heating duration of less than 9 minutes, the energy yield is less than 80% of the calorific value of wood due to a decrease in gas yield (example 2). When the heating time of wood is more than 35 minutes, the energy yield is less than 80% due to a decrease in the calorific value of gas (example 7).

Upon receipt of gaseous fuel according to the proposed method with a steam flow rate of less than 0.7 kg / kg a.s.d., for example, 0.6 kg / kg a.s.d., the gas yield is reduced to 1.2 m ³ / kg ASD, which reduces the energy output to 76.7%.

Thus, the implementation of the process according to the proposed method will allow to obtain gaseous fuel with a large 1.6 times calorific value and 1.3 times the energy output compared to the known method.

The reliability of the results is confirmed by a large number of experimental data. The laboratory study of the proposed method was completed, an experimental installation was created. The work is at the stage of obtaining initial data for industrial design at a pilot plant.

The proposed method for producing gaseous fuel from wood aroused the interest of several organizations (for example, the FSUE "Amzinsky LC", Bashkortostan), their consent was obtained for the creation of a pilot plant for them.

Sources of information taken into account during the examination

1. Geletukha G.G., Zheleznaya G.A. Overview of biomass gasification technology // Ecotechnologies and Resource Saving. - 1998. - No. 2. - p.21-30.

2. Lyamin VA, Gasification of wood. // - M. - Iz-in “Forest industry”. - 1967. - p. 18.

Claims (1)

A method of producing gaseous fuel, including heating wood raw materials to 900-1100 ° C and subsequent processing of the obtained carbonizate with water vapor, characterized in that the wood is heated for 9-35 minutes with a steam consumption of at least 0.7 kg per 1 kg absolutely dry wood.