CN102384459B - Waste heat boiler for preparing olefins from methanol - Google Patents

Abstract

The invention discloses a methanol-to-olefins waste heat boiler that can meet various steam requirements in a methanol-to-olefins system, comprising a vertically arranged heat-insulating furnace, a vertically arranged secondary heat exchange channel and connecting the upper end of the heat-insulated furnace with the The main heat exchange channel at the upper end of the auxiliary heat exchange channel, the lower end of the adiabatic furnace is provided with a flue gas inlet, the lower end of the auxiliary heat exchange channel is provided with a flue gas outlet, several superheaters are arranged in the main heat exchange channel, and the auxiliary heat exchange channel There are several groups of economizers arranged from top to bottom, and a heat booster for raising the temperature of the flue gas in the adiabatic furnace is arranged on the side wall above the flue gas inlet of the adiabatic furnace. The advantage of the present invention is that after adding a superheater on the side wall of the adiabatic furnace, the temperature of the high-temperature flue gas in the adiabatic furnace can be increased, so that the temperature and the amount of steam generated by the heater can be increased, and the methanol-to-olefins system can be satisfied. Power generation requirements and most process steam requirements.

Description

Waste heat boiler for methanol to olefins

technical field

The invention relates to a waste heat boiler for methanol to olefin.

Background technique

Methanol-to-olefins technology is a new way to produce olefins from non-oil raw materials, which will greatly alleviate the dependence on petroleum resources, effectively and cleanly utilize coal resources, alleviate the situation of methanol overcapacity, extend the coal chemical industry chain, and promote coal chemical industry The sustainable and healthy development of the industry will play an important role. As an important equipment in the methanol-to-olefins (MTO) plant, the waste heat boiler is used to recover the high-temperature CO flue gas energy of the MTO plant, protect the environment, and enable the entire MTO system to operate normally. The waste heat boiler includes: a vertically arranged adiabatic furnace, a vertically arranged auxiliary heat exchange channel, and a main heat exchange channel connecting the upper end of the adiabatic furnace and the upper end of the auxiliary heat exchange channel. The lower end of the adiabatic furnace is provided with a flue gas inlet. The lower end of the passage is provided with a flue gas outlet, several superheaters are arranged in the main heat exchange passage, and several sets of economizers are arranged in the auxiliary heat exchange passage from top to bottom. Due to the special process of methanol to olefins, the temperature of high-temperature flue gas before heat recovery is about 615°C, that is, the highest temperature in the adiabatic furnace of the above-mentioned waste heat boiler is about 615°C. After heat recovery of high-temperature flue gas, the waste heat boiler It can only supply ordinary process steam, which cannot meet the steam demand of the whole system of methanol to olefins.

Contents of the invention

The technical problem to be solved by the present invention is to provide a waste heat boiler for methanol to olefins that can meet various steam consumption requirements in the methanol to olefins system.

In order to solve the above technical problems, the technical solution adopted in the present invention is: a waste heat boiler for methanol to olefins, including a vertically arranged adiabatic furnace, a vertically arranged auxiliary heat exchange channel, and an upper end of the adiabatic furnace connected to the auxiliary heat exchanger. The main heat exchange channel at the upper end of the heat channel, the lower end of the adiabatic furnace is provided with a flue gas inlet, the lower end of the auxiliary heat exchange channel is provided with a flue gas outlet, and several superheaters are arranged in the main heat exchange channel, and the auxiliary heat exchange channel is installed from the top Several groups of economizers are arranged below, and the side wall of the adiabatic furnace located above the flue gas inlet is provided with a warmer for increasing the temperature of the flue gas in the adiabatic furnace.

The superheater is a burner using gas as a combustion raw material.

One side of the heat exchange tubes in the superheater and the economizer is respectively provided with a pulse soot blower for removing soot deposited on the heat exchange tubes.

A water supply device is provided on the outside of the auxiliary heat exchange channel. The water supply device includes a main pipe and several branch pipes. The branch pipes respectively connect the water inlet or outlet of the economizer with the main pipe. The section between the two branch pipes connecting the water inlet and the water outlet of the economizer is respectively provided with a main control valve, one end of the main pipe is provided with a main water inlet, and the other end is provided with a main water outlet.

The secondary heat exchange channel is assembled from several sub-channels, and each economizer is respectively fixed in the sub-channels; or the secondary heat exchange channel is assembled from several sub-channels, and each economizer Correspondingly fixed in the sub-channels, the water inlet and outlet of each economizer are respectively connected to branch pipes, and the sub-channels, economizers and branch pipes form an installation unit.

The beneficial effects of the present invention are: recovery of the high-temperature CO flue gas energy of the MTO device, environmental protection, increasing the temperature of the high-temperature flue gas in the adiabatic furnace after adding a warmer on the side wall of the adiabatic furnace, thereby increasing the heat generated by the heater. The temperature and steam volume of the steam can meet the power generation requirements in the methanol to olefins system and the steam requirements of most processes. The modular structure reduces the workload of on-site installation, and the economizer sub-units are conducive to flexible operation and maintenance.

Description of drawings

Figure 1 is a structural diagram of a waste heat boiler for methanol to olefins in the present invention.

In the figure: 1. Insulated furnace, 2. Secondary heat exchange channel, 3. Main heat exchange channel, 4. Flue gas inlet, 5. Flue gas outlet, 6. Superheater, 7. Economizer, 8. Burner, 9. Pulse soot blower, 10. Sub-channel, 11. Main pipe, 12. Branch pipe, 13. Sub-control valve, 14. Main control valve, 15. Main water inlet, 16. Main water outlet.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, a waste heat boiler for methanol to olefins includes a vertically arranged adiabatic furnace 1, a vertically arranged auxiliary heat exchange channel 2, and a main heat exchanger connecting the upper end of the adiabatic furnace 1 and the upper end of the auxiliary heat exchange channel 2. The heat channel 3, the lower end of the adiabatic furnace 1 is provided with a flue gas inlet 4, the lower end of the secondary heat exchange channel 2 is provided with a flue gas outlet 5, and the main heat exchange channel 3 is provided with several superheaters 6, the specific number of superheaters 6 Set it yourself according to the actual production requirements. A row of economizers 7 is arranged in the secondary heat exchange channel 2 from top to bottom, and a heat booster for increasing the flue gas temperature in the adiabatic furnace 1 is provided on the side wall above the flue gas inlet 4 of the adiabatic furnace 1 . In the present invention, the superheater uses gas as the burner 8 for burning raw materials. Of course, in actual production, it can be changed to other intensifiers according to the actual situation, as long as the temperature of the flue gas in the adiabatic furnace 1 can be improved. In order to avoid dust accumulation on the superheater 6 and the economizer 7 after working for a long time and affect the heat exchange efficiency, the heat exchange tubes in the superheater 6 and the economizer 7 are respectively provided with dust collectors for removing the accumulation on the heat exchange tubes. Ash pulse sootblower9. Waste heat boilers usually transport all parts to the installation site, and then weld them together on site, that is, the on-site installation workload is very large. In order to reduce the workload of on-site installation, the auxiliary heat exchange channel 2 is decomposed into several sub-channels 10, and each sub-channel 10 is correspondingly equipped with an economizer 7, that is, the sub-channel 10 and the economizer 7 form an installation unit , After arriving at the installation site, you only need to connect multiple installation units, which reduces the installation workload on site. In order to avoid affecting the normal operation of all economizers due to the damage of a single economizer 7, a water supply device is provided outside the secondary heat exchange channel 2. The water supply device includes a main pipe 11 and several branch pipes 12. The branch pipes 12 connect the economizers 7 respectively The water inlet or outlet is connected to the main pipe 11, and the branch pipes 12 are respectively provided with sub-control valves 13, and the section of the main pipe 11 between the two branch pipes 12 connected to the water inlet and water outlet of the same economizer 7 is respectively provided with a main The control valve 14 is provided with a main water inlet 15 at one end of the main pipe 11 and with a main water outlet 16 at the other end. In actual production, each branch pipe 12 can also be connected to the water inlet or water outlet of the economizer 7 in the installation unit in advance to form a new installation unit.

The working principle of the present invention is: as shown in Figure 1, high-temperature flue gas enters the adiabatic furnace 1 from the flue gas inlet 4, and at the same time, the burner 8 heats the flue gas in the adiabatic furnace 1 to increase the temperature of the flue gas in the adiabatic furnace 1. temperature, the flue gas with increased temperature exchanges heat with the superheater 6 and the economizer 7, which increases the temperature of the steam generated by the superheater 6. Most equipment that requires process steam. The flue gas after the heat exchange is exhausted from the flue gas outlet 5 . In the main water inlet 15, deoxygenated water is introduced. When no economizer 7 is damaged, all main control valves 14 are closed, and the secondary control valves 13 on all branch pipes 12 are opened. The branch pipe connected to the water inlet of the economizer 7 enters the bottom economizer 7, and then enters the main pipe 11 from the branch pipe connected to the water outlet of the bottom economizer 7 and flows upwards. By analogy, the deoxygenated water passes through all the economizers. Coal device and finally send out from the total water outlet 16 on the main pipe 11 and make other usefulness. When a certain economizer is damaged, it is only necessary to open the corresponding main control valve and close the corresponding auxiliary control valve. The auxiliary control valve 15 on the two branch pipes 12 connected to the lower economizer is enough. At this time, the deoxygenated water will pass through the lowermost main control valve 14, and then enter the upper one from the branch pipe connected to the upper economizer water inlet. The economizer, then conducts heat exchange with high-temperature flue gas, that is, the flow line of deoxygenated water bypasses the damaged economizer, so that the damaged economizer will not affect the heat exchange of the entire deoxygenated water.

Claims (1)

1. the waste heat boiler that is used for methanol-to-olefins; Comprise the adiabatic furnace of vertical arranged, the secondary heat exchanger channels and the main heat exchange passage that is connected adiabatic furnace upper end and secondary heat exchanger channels upper end of vertical arranged, the lower end of adiabatic furnace is provided with gas approach, and the lower end of secondary heat exchanger channels is provided with exhanst gas outlet; Be provided with several superheaters in the main heat exchange passage; Be provided with some groups of economizers from top to bottom in the secondary heat exchanger channels, it is characterized in that: the sidewall that said adiabatic furnace is positioned at the gas approach top is provided with the heat booster that is used to improve the adiabatic furnace flue-gas temperature, and said heat booster is to utilize the burner of combustion gas as combustion material; Heat exchanger tube one side in said superheater and the economizer is respectively arranged with the pulse soot blower that is used to remove dust stratification on the heat exchanger tube; Said secondary heat exchanger channels arranged outside has water supply installation, and water supply installation comprises house steward and some arms, and arm links to each other the water inlet or the delivery port of economizer respectively with house steward; Be respectively arranged with the sub-control valve on the arm; House steward last with two arms that the water inlet and the delivery port of same economizer link to each other between one section be respectively arranged with main control valve, house steward's a end is provided with total water inlet, the other end is provided with total delivery port; Said secondary heat exchanger channels is assembled by some subchannels; And what each economizer was corresponding respectively is fixed in the subchannel, and the water inlet of each economizer and delivery port be connecting branch respectively, and subchannel, economizer and arm form an installation unit.

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