WO2014107910A1

WO2014107910A1 - Drying method and drying apparatus for lignite particles and pulverized coal after granulation

Info

Publication number: WO2014107910A1
Application number: PCT/CN2013/070560
Authority: WO
Inventors: 蔡京鹏
Original assignee: Cai Jingpeng
Priority date: 2013-01-11
Filing date: 2013-01-16
Publication date: 2014-07-17
Also published as: CN103060048A

Abstract

A drying method and a drying apparatus for lignite particle and pulverized coal after granulation. The method is: a lignite raw material is sieved and crushed into particles between 4 mm and 50 mm in particle diameter or granules of less than 4 mm are made into particles between 4 mm and 12 mm in particle diameter and then transported into a pressure vessel to be sealed; then, a low-pressure high-temperature superheated steam is introduced into the pressure vessel, the superheated steam is introduced into the pressure vessel for heat exchange with the lignite particles, and, either when the lignite particles reaches a temperature between 130°C and 290°C or when the pressure within the pressure vessel is greater than or equal to 1.5 megapascals, supply of the superheated steam is ceased and pressure stabilization is commenced; and, after 10 minutes of pressure stabilization, a modified coal heated by the superheated steam is extracted and stacked for cooling in natural conditions. The present invention uses the superheated steam as a heat medium to allow the lignite particles to be modified towards characteristics of bituminous coal. The pressure vessel of the present invention effectively ensures that the lignite particles are dried in the optimal temperature and pressure, discharges waste gas and condensed water in a timely manner, allows the dried lignite particles to be provided with significantly reduced water content and minimized re-absorption and to be free from spontaneous combustion and weathering, and provides significantly increased calorific value per unit.

Description

Granite granule and drying method and drying equipment after pulverization of pulverized coal

Technical field

The invention relates to the field of coal processing and utilization, in particular to granules of lignite and drying technology after pulverization of pulverized coal.

Background technique

Over the years, a lot of research and experiments have been done on the technical process of reducing the moisture of lignite to improve the quality of lignite. There are many kinds of methods, but there are no mature technical processes. There are many drawbacks, mainly: 1. After drying the coal or Completely has the disadvantage of lignite, easy to spontaneous combustion, weathering, easy to absorb water and return to the tide. 2. Dry lignification due to low lignite burning point, hot air drying is dangerous, easy to catch fire or even explode; environmental pollution control is poor, wet method (steam) drying with fluidized bed drying, steam consumption, High energy consumption, high production cost, and expensive equipment.

Summary of the invention

In view of the problems existing in the prior art, the object of the invention is to provide a granule of lignite and a drying method and drying apparatus after pulverization of pulverized coal. The lignite granules dried by the technology have a significant decrease in moisture, and the suckback is extremely small, and spontaneous combustion and weathering do not occur, the unit heat generation is greatly increased, and the amount of steam is small, and the equipment cost is low.

The technical solution adopted by the present invention to solve its technical problems is:

A granule of lignite and a drying method after granulating pulverized coal, the drying steps are as follows:

1 The particles larger than 50 mm in the lignite raw material are sieved and broken into particles having a particle diameter of 4 mm to 50 mm, and the particles smaller than 4 mm are granulated into particles having a particle diameter of 4 mm to 12 mm;

2 The lignite granules after sieving, crushing or granulation are sent to the pressure vessel for sealing;

3 Introducing a low-pressure high-temperature superheated steam into the pressure vessel, the temperature of the superheated steam passing through is higher than or equal to 300 ° C, and the superheated steam pressure is less than or equal to 2.0 MPa;

4 The superheated steam is introduced into the pressure vessel for heat exchange with the lignite particles. When the lignite particle temperature reaches 130 ° C to 290 ° C, or the pressure in the pressure vessel is greater than or equal to 1.5 MPa, the supply of superheated steam is stopped, and the pressure is started;

5 After 10 minutes of voltage regulation, the steam in the vessel is evacuated by a pressure vessel, and the modified coal heated by hot steam is taken out and stacked under natural conditions for cooling.

Further, the above steps 1-5 may be repeated several times to achieve a desired moisture content of the modified coal.

Further, the temperature of the superheated steam introduced in step 3 is higher than or equal to 400 °C.

Further, the pressure vessel is an autoclave, and the autoclave comprises a cylinder, and the cylinder is respectively provided with an interface connecting a pressure gauge and a temperature gauge; and an inlet device connecting the superheated steam pipeline is disposed in the cylinder The bottom of the body; at the bottom of the cylinder is also provided with a sewage outlet for discharging condensed water; and an exhaust port for discharging sulfur dioxide and steam in the kettle is arranged at the top or the side of the cylinder.

Further, the autoclave cylinder is further provided with an inflation port and a venting port for stabilizing the superheated steam pressure in the cylinder.

Further, a rail is disposed in the autoclave cylinder, and the steaming cart is pushed into the cylinder along the rail.

Compared with the prior art, the beneficial effects of the present invention are:

The drying technology of the invention uses superheated steam as a heat medium, and heats the lignite particles to a high temperature of 300 ° C or higher in the autoclave, so that the lignite particles are modified to have the characteristics of bituminous coal, and at the same time, the dehydration and desulfurization are largely eliminated. The pressure vessel of the invention effectively ensures that the lignite particles are dried under the optimal temperature and pressure, and the exhaust gas and the condensed water are discharged in time, the amount of steam is small, and the equipment cost is low. The moisture content of the lignite particles after drying is significantly reduced, the suckback is extremely small, self-ignition and weathering do not occur, and the unit calorific value is greatly improved.

DRAWINGS

Figure 1 is a schematic front view showing the autoclave of the present invention;

Figure 2 is a side view showing the structure of the autoclave of the present invention;

3 is a schematic view showing the drying process of the brown coal of the present invention.

detailed description

A granule of lignite and a drying method after granulation of pulverized coal, as shown in Fig. 3, the drying steps are as follows:

1 The particles larger than 50 mm in the lignite raw material are sieved and broken into particles having a particle diameter of 4 mm to 50 mm, and particles smaller than 4 mm are granulated into particles having a particle diameter of 4 mm to 12 mm.

2 The lignite granules after sieving, crushing or granulation are sent to a pressure vessel for sealing. The effective charging volume of the invention is 10 m3 to 400 The autoclave of m3 is even an autoclave with a larger effective charge volume. The sieved and crushed lignite granules of the present invention are sent to the autoclave by a steaming basket or a steaming car, and the spherical cap 11 is sealed. Lignite pellets placed on steaming baskets or steaming carts should be kept breathable.

The autoclave shown in FIG. 1 comprises a cylinder 1 supported by a saddle support 14 having a spherical cap 11 at one end and an elliptical head 12 at the other end. The spherical cap 11 and the cylinder 1 are provided with a safety interlocking device 13 for locking.

The cylinders 1 are respectively provided with

interfaces

2 and 3 for connecting a pressure gauge and a temperature gauge, and the operation conditions in the autoclave are monitored by a pressure gauge and a temperature gauge.

The bottom of the cylinder 1 is provided with an air inlet 5 which connects the superheated steam pipe and the steam inlet means 4 in the cylinder 1. A drain outlet 6 is also arranged at the bottom of the cylinder body, and the drain outlet 6 is provided with a steam trap, and the condensed water and dirt in the kettle are discharged out of the kettle through the steam trap. An exhaust port 7 for discharging sulfur dioxide and steam in the kettle is disposed at the top of the cylinder 1. The cylinder 1 is also provided with an inflation port 8 and a venting port 9 for stabilizing the superheated steam pressure in the cylinder.

As shown in FIG. 2, a rail 15 is disposed in the cylinder 1, and the steaming cart is pushed into the cylinder 1 along the rail, the spherical cap 11 is closed, and the spherical cap 11 is locked by the safety interlock device 13 Insurance sales. When the steam pressure of the steam boiler reaches 0.7 MPa or more, the spherical cap 11 is inflated through the inflation port, and the spherical cap 11 is sealed by a gasket, and the sealing pressure of the spherical cap 11 is ≥450°.

3 After the spherical cap 11 is sealed, the valve of the air inlet 5 is opened, and the superheated steam of low pressure and high temperature is introduced into the autoclave, and the temperature of the superheated steam is higher than or equal to 300 ° C, preferably the temperature of the superheated steam is higher than Or equal to 400 ° C, the higher the temperature, the higher the heat of the steam, the smaller the steam consumption, the shorter the production cycle, the higher the utilization rate of the equipment; the steam temperature can not be lower than 300 ° C, the steam temperature is low, it is difficult to coal Heat to the desired temperature. The superheated steam pressure is less than or equal to 2.0 MPa, the steam pressure does not have to be too high, and the high pressure will inevitably result in high boiler cost, high risk and high maintenance requirements.

4 The superheated steam is introduced into the pressure vessel for heat exchange with the lignite particles, and the condensed water is discharged from the trap of the sewage outlet 6 at the bottom of the cylinder 1, and the temperature inside the cylinder and the coal temperature are continuously increased, and the pressure inside the cylinder is also continuously increased. The operation in the autoclave was monitored by a pressure gauge and a thermometer. When the lignite particle temperature reaches 130 ° C ~ 290 ° C when the lignite particle temperature reaches 130 ° C ~ 290 ° C, or the pressure in the pressure vessel is greater than or equal to 1.5 MPa, close the valve of the inlet 5, stop supplying superheated steam, start to stabilize Pressure. When the temperature of lignite particles exceeds the burning point of coal by 20 °C (the burning point of lignite varies from 110 °C to 270 °C according to the degree of development of the lignite to the old lignite, respectively), the higher the temperature of the superheated steam supplied, the higher the voltage The lower the pressure requirement in the point container, the coal temperature cannot exceed the ignition point too much, and the high volatile content is easily lost. Because the strength of lignite is poor, the pressure inside the cylinder is too large, and it is easy to break the particles into powder to affect the vapor permeability.

5 After 10 minutes of voltage regulation, the longer the time, the better. During this period, a series of modification reactions will occur inside the lignite: the sulfur and oxygen are greatly reduced, and the sulfur dioxide is generated by the exhaust port 7 located at the top of the cylinder 1; the coal tar and the large amount of pore water in the pores of the coal particles are displaced toward the surface of the particle. The volume is reduced and so on. The valve of the exhaust port 7 is opened, the steam in the cylinder is evacuated, the valve of the inflation port 8 is closed, the valve of the venting port 9 is opened, and the pressure of the seal of the spherical cap 11 is released. After the pressure of the sealing head of the spherical cap 11 is released, the safety pin is pulled out, the safety interlocking device 13 is rotated, the spherical cap 11 is opened, the modified coal heated by the hot steam is taken out, and the cooling is piled up under natural conditions. Since the pore water inside the modified coal has mostly become surface water (partially evaporated by the superheated steam in the vessel, the total moisture of the coal will be reduced by 30% to 40%), and the moisture of the coal will be naturally in the coal pile. During the cooling process, the surface water gradually balances with the moisture content of the surrounding air. On sunny days, the total water can be reduced to 10% to 20% after 48 hours, and between 18% and 25% in rainy days.

If the total water content of the coal is to be lowered, repeat steps 1-5 several times, and the minimum moisture can be reduced to less than 1%. However, the volume reduction of coal particles has a certain limit, and generally can only be reduced by 15% to 20%. When the water drops too low, the strength of the particles becomes worse, and the lignite has a high volatile content, and when the water content is less than 12%, it is disadvantageous for use as a thermal coal to a power plant.

The above embodiments are only for explaining the technical idea of the present invention, and the scope of protection of the present invention is not limited thereto. Any modification made based on the technical idea according to the technical idea of the present invention falls within the protection scope of the present invention. Inside.

Claims

A method for drying granules of lignite and pulverized pulverized coal, characterized in that the drying steps are as follows:

1 The particles larger than 50 mm in the lignite raw material are sieved and broken into particles having a particle diameter of 4 mm to 50 mm, and the particles smaller than 4 mm are granulated into particles having a particle diameter of 4 mm to 12 mm;

2 The lignite granules after sieving, crushing or granulation are sent to the pressure vessel for sealing;

3 Introducing a low-pressure high-temperature superheated steam into the pressure vessel, the temperature of the superheated steam passing through is higher than or equal to 300 ° C, and the superheated steam pressure is less than or equal to 2.0 MPa;

4 The superheated steam is introduced into the pressure vessel for heat exchange with the lignite particles. When the lignite particle temperature reaches 130 ° C to 290 ° C, or the pressure in the pressure vessel is greater than or equal to 1.5 MPa, the supply of superheated steam is stopped, and the pressure is started;

5 After 10 minutes of voltage regulation, the steam in the vessel is evacuated by a pressure vessel, and the modified coal heated by the hot steam is taken out and stacked under natural conditions for cooling.
A method of drying lignite granules and pulverized coal granules according to claim 1, wherein the steps 1-5 are repeated several times to achieve a desired moisture content of the modified coal.
The method for drying granules of lignite and pulverized coal after pulverization according to claim 1 or 2, wherein the temperature of the superheated steam introduced in the step 3 is higher than or equal to 400 °C.
The method for drying granules of lignite and pulverized pulverized coal according to claim 1 or 2, wherein the pressure vessel is an autoclave, and the autoclave comprises a cylinder, The cylinder body is respectively provided with an interface for connecting a pressure gauge and a temperature gauge; a steam inlet device connecting the superheated steam pipeline is arranged at the bottom of the cylinder; at the bottom of the cylinder body, a sewage outlet for discharging condensed water is further disposed; a sulfur dioxide is discharged and The exhaust port of the steam in the kettle is placed on the top or side of the cylinder.
The method for drying granules of lignite and pulverized pulverized coal according to claim 3, wherein the pressure vessel is an autoclave, and the autoclave comprises a cylinder, the cylinder An inlet port for connecting the pressure gauge and the temperature meter is respectively arranged; a steam inlet device connecting the superheated steam pipe is arranged at the bottom of the cylinder; and a sewage outlet for discharging the condensed water is arranged at the bottom of the cylinder; a sulfur dioxide and a kettle are discharged The steam exhaust port is provided at the top or side of the cylinder.
The method for drying granules of lignite and pulverized coal after pulverization according to claim 4, wherein the autoclave cylinder is further provided with an inflation port for stabilizing the superheated steam pressure in the cylinder and Air port.
The granule of lignite and the method for drying pulverized coal after pulverization according to claim 5, wherein the autoclave cylinder is further provided with an inflation port for stabilizing the superheated steam pressure in the cylinder and Air port.
The method for drying granules of lignite and pulverized pulverized coal according to claim 4, wherein a rail is disposed in the autoclave cylinder, and a steaming cart is pushed into the cylinder along the rail.
The method for drying granules of lignite and pulverized pulverized coal according to claim 5, wherein a rail is disposed in the autoclave cylinder, and a steaming cart is pushed into the cylinder along the rail.