Titanium dioxide production gas powder waste heat recycling system

Abstract

A heat exchange coil pipe is arranged in a gas-powder heat exchanger, a water outlet of a central washing water tank is connected with a water outlet pipe through a booster pump, the water outlet pipe is connected with one end of the heat exchange coil pipe, the other end of the heat exchange coil pipe is connected with a hot water pipe, and the hot water pipe is connected into a side washing water tank. A water outlet in the lower portion of the side washing water tank is connected with a hot water conveying header pipe through a hot water pump, the hot water conveying header pipe is connected with six hot water branch pipes, and the six hot water branch pipes are connected into medium inlets in the lower portions of the six heat exchangers respectively. The water return branch pipes are connected into the water return main pipe and then return to the water outlet pipe; and hot water outlet pipes of the six heat exchangers are connected into a heating area and a production process. The system is simple and reasonable in design and convenient to operate. The heat exchange coil recovers heat and exchanges the recovered heat for a factory heating system and a production process, so that the energy utilization rate of titanium dioxide production by a sulfuric acid method can be improved, the use of steam can be reduced, and the comprehensive utilization rate of energy can be improved.

Description

Technical Field

[0001] This utility model belongs to the field of titanium dioxide production technology, specifically relating to a waste heat recovery system for titanium dioxide production. Background Technology

[0002] In the sulfuric acid process for titanium dioxide production, ilmenite undergoes a series of processes including raw ore crushing, acidolysis, hydrolysis, water washing, pre-kiln pressure filtration, calcination, grinding, pulping, surface treatment, and steam-powdering to ultimately produce finished titanium dioxide. In the steam-powdering section, the titanium dioxide is crushed using a steam-powdering mill. This crushing process requires a large amount of steam; each mill uses 2.5 tons of medium-pressure steam per hour. The heat of the steam in the mill comes from the steam-powdering heat exchanger, whose outlet temperature can reach 180°C. After supplying the mill, the temperature inside the heat exchanger remains close to 180°C. Current technology fails to fully recover and utilize this heat, resulting in significant heat waste. Simultaneously, the plant's heating system and the heating of the hot water tanks also require large amounts of steam, further increasing steam usage costs. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a waste heat recovery system for titanium dioxide production.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a waste heat recovery system for titanium dioxide production, comprising a central washing tank and multiple gas-powder heat exchangers, characterized in that: the gas-powder heat exchangers are equipped with heat exchange coils; the outlet of the central washing tank is connected to an outlet pipe via a booster pump; the outlet pipe is connected to one end of the heat exchange coil; the other end of the heat exchange coil is connected to a hot water pipe; the hot water pipe is connected to a side washing tank; the outlet at the bottom of the side washing tank is connected to a hot water delivery main pipe via a hot water pump; the hot water delivery main pipe is connected to six hot water branch pipes; the six hot water branch pipes are respectively connected to the media inlets at the bottom of heat exchangers No. 1, No. 2, No. 3, No. 4, No. 5, and No. 6; the media outlets of the six heat exchangers are respectively connected to the return water main pipe via return water branch pipes; the return water main pipe is connected to the outlet pipe.

[0005] The first hot water outlet pipe of heat exchanger No. 1 is connected to the western heating zone, the fourth hot water outlet pipe of heat exchanger No. 4 is connected to the eastern heating zone, the second hot water outlet pipe of heat exchanger No. 2 and the third hot water outlet pipe of heat exchanger No. 3 are respectively connected to the first washing hot water tank a and the second washing hot water tank a; the fifth hot water outlet pipe of heat exchanger No. 5 and the sixth hot water outlet pipe of heat exchanger No. 6 are respectively connected to the first washing hot water tank b and the second washing hot water tank b.

[0006] The first water inlet pipe at the top of heat exchanger No. 1 and the fourth water inlet pipe at the top of heat exchanger No. 4 are both connected to the water supply pipe of the production system; the second water inlet pipe at the top of heat exchanger No. 2, the third water inlet pipe at the top of heat exchanger No. 3, the fifth water inlet pipe at the top of heat exchanger No. 5, and the sixth water inlet pipe at the top of heat exchanger No. 6 are respectively connected to the cooling water pipe of the corresponding slag cooler.

[0007] The gas-powder heat exchanger consists of four units connected in parallel: the first gas-powder heat exchanger, the second gas-powder heat exchanger, the third gas-powder heat exchanger, and the fourth gas-powder heat exchanger.

[0008] The condensate outlet pipes of the gas-powder heat exchanger are all connected to the central washing tank.

[0009] The side-wash water tank is equipped with a thermometer and a level gauge. The level gauge is interlocked with the hot water pump and is automatically controlled by the DCS system. When the level gauge detects that the water level in the side-wash water tank reaches 80%, the hot water pump starts. When the water level in the side-wash water tank is lower than 20%, the hot water pump automatically reduces the pumping frequency.

[0010] A water temperature gauge is installed on each of the first, second, third, fourth, fifth, and sixth hot water outlet pipes.

[0011] Each of the heat exchangers No. 2, No. 3, No. 5 and No. 6 is equipped with a control valve and an inlet thermometer on the corresponding hot water branch pipe. The four control valves are interlocked with the outlet thermometers on the hot water outlet pipes of the four heat exchangers.

[0012] The outlet pipe is connected to a drain pipe, which is used for cleaning the gas-powder heat exchanger and for the water to directly enter the side wash tank when the return water main is drained.

[0013] The beneficial effects of this utility model are: the system design is simple and reasonable, and the operation is convenient. By adding heat exchange coils inside the gas-powder heat exchanger, heat is recovered through the heat exchange coils and exchanged for use in the plant heating system and production processes. This not only improves the energy utilization rate of sulfuric acid process titanium dioxide production, but also reduces the use of steam and improves the overall energy utilization rate. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the present invention;

[0015] In the diagram: A - Air-powder heat exchanger, A1 - First air-powder heat exchanger, A2 - Second air-powder heat exchanger, A3 - Third air-powder heat exchanger, A4 - Fourth air-powder heat exchanger; B - Side wash water tank, C - Hot water pump, D1 - Heat exchanger No. 1, D2 - Heat exchanger No. 2, D3 - Heat exchanger No. 3, D4 - Heat exchanger No. 4, D5 - Heat exchanger No. 5, D6 - Heat exchanger No. 6, G1 - First wash hot water tank a, G2 - First wash hot water tank b, H1 - Second wash hot water tank a, H2 - Second wash hot water tank b; T1 - Outlet water thermometer, T2 - Inlet water thermometer; L - Outlet pipe, L1 - Hot water pipe, L2 - Hot water main pipe, L3 - Drain pipe, R - Return water main pipe, r - Return water branch pipe; K1 - First hot water outlet pipe, K2 - Second hot water outlet pipe, K3 - Third hot water outlet pipe, K4 - Fourth hot water outlet pipe K5 - Fifth hot water outlet pipe, K6 - Sixth hot water outlet pipe; S1 - First water inlet pipe, S2 - Second water inlet pipe, S3 - Third water inlet pipe, S4 - Fourth water inlet pipe, S5 - Fifth water inlet pipe, S6 - Sixth water inlet pipe. Detailed Implementation

[0016] See the example. Figure 1 A waste heat recovery system for titanium dioxide production includes a central washing tank and multiple gas-powder heat exchangers A. The system is characterized by: heat exchange coils within each gas-powder heat exchanger A; the outlet of the central washing tank is connected to an outlet pipe L via a booster pump; the outlet pipe L is connected to one end of each heat exchange coil; the other end of the heat exchange coil is connected to a hot water pipe L1; the hot water pipe L1 is connected to a side washing tank B; the outlet at the bottom of the side washing tank B is connected to a hot water delivery main pipe L2 via a hot water pump C; the hot water delivery main pipe L2 is connected to six hot water branch pipes; these six branch pipes are respectively connected to the media inlets at the bottom of heat exchangers D1, D2, D3, D4, D5, and D6; the media outlets of the six heat exchangers are respectively connected to a return water main pipe R via return water branch pipes r; and the return water main pipe R is connected to the outlet pipe L.

[0017] The first hot water outlet pipe K1 of the No. 1 heat exchanger D1 is connected to the western heating zone, the fourth hot water outlet pipe K4 of the No. 4 heat exchanger D4 is connected to the eastern heating zone, and the second hot water outlet pipe K2 of the No. 2 heat exchanger D2 and the third hot water outlet pipe K3 of the No. 3 heat exchanger D3 are respectively connected to the first washing hot water tank a G1 and the second washing hot water tank a H1.

[0018] The fifth hot water outlet pipe K5 of heat exchanger D5 and the sixth hot water outlet pipe K6 of heat exchanger D6 are respectively connected to the first washing hot water tank bG2 and the second washing hot water tank bH2.

[0019] The first water inlet pipe S1 on the upper part of heat exchanger D1 and the fourth water inlet pipe S4 on the upper part of heat exchanger D4 are both connected to the water supply pipe of the production system; the second water inlet pipe S2 on the upper part of heat exchanger D2, the third water inlet pipe S3 on the upper part of heat exchanger D3, the fifth water inlet pipe S5 on the upper part of heat exchanger D5, and the sixth water inlet pipe S6 on the upper part of heat exchanger D6 are respectively connected to the cooling water pipe of the corresponding slag cooler.

[0020] The gas-powder heat exchanger A consists of four units connected in parallel: the first gas-powder heat exchanger A1, the second gas-powder heat exchanger A2, the third gas-powder heat exchanger A3, and the fourth gas-powder heat exchanger A4.

[0021] The condensate outlet pipes of the gas-powder heat exchanger A are all connected to the central washing tank.

[0022] The side-wash water tank B is equipped with a thermometer and a level gauge. The level gauge is interlocked with the hot water pump C and is automatically controlled by the DCS system. When the level gauge L detects that the water level in the side-wash water tank B reaches 80%, the hot water pump C starts. When the water level in the side-wash water tank B is lower than 20%, the hot water pump C automatically reduces the pumping frequency.

[0023] A water outlet thermometer T1 is installed on each of the first hot water outlet pipe K1, the second hot water outlet pipe K2, the third hot water outlet pipe K3, the fourth hot water outlet pipe K4, the fifth hot water outlet pipe K5, and the sixth hot water outlet pipe K6.

[0024] The hot water branch pipes connected to heat exchangers D2, D3, D5, and D6 are each equipped with a control valve and an inlet thermometer T2. The four control valves are interlocked with the outlet thermometers T1 on the hot water outlet pipes of the four heat exchangers.

[0025] The outlet pipe L is connected to the drain pipe L3, which is used for cleaning the gas-powder heat exchanger A and for the water to directly enter the side wash water tank B when the return water main pipe R is drained.

[0026] Instructions for use:

[0027] Due to limitations in heat recovery, heat exchangers No. 1 (D1) and No. 4 (D4) supplying heating cannot be used simultaneously with heat exchangers No. 2 (D2), No. 3 (D3), No. 5 (D5), and No. 6 (D6) supplying hot water to the first and second washing water tanks.

[0028] For winter heating, heat exchanger No. 1 (D1) and heat exchanger No. 4 (D4) are used.

[0029] In other seasons, heat exchangers No. 2 (D2), No. 3 (D3), No. 5 (D5), and No. 6 (D6) are used.

[0030] To facilitate switching, manual valves are installed on the first water inlet pipe S1, the second water inlet pipe S2, the third water inlet pipe S3, the fourth water inlet pipe S4, the fifth water inlet pipe S5, and the sixth water inlet pipe S6 for control.

Claims

1. A system for recycling waste heat from gas powder in titanium dioxide production, comprising a central washing water tank and a plurality of gas powder heat exchangers (A), characterized in that: The gas powder heat exchanger (A) is internally provided with a heat exchange coil, the water outlet of the central washing tank is connected with an outlet water pipe (L) through a booster pump, the outlet water pipe (L) is connected with one end of the heat exchange coil, the other end of the heat exchange coil is connected with a hot water pipe (L1), the hot water pipe (L1) is connected with a side washing tank (B), the water outlet at the lower part of the side washing tank (B) is connected with a hot water conveying main pipe (L2) through a hot water pump (C), the hot water conveying main pipe (L2) is connected with six hot water branch pipes, and the six hot water branch pipes are connected with the medium inlets at the lower parts of a first heat exchanger (D1), a second heat exchanger (D2), a third heat exchanger (D3), a fourth heat exchanger (D4), a fifth heat exchanger (D5) and a sixth heat exchanger (D6) respectively; the medium outlets of the six heat exchangers are connected with a backwater main pipe (R) through backwater branch pipes (r) respectively, and the backwater main pipe (R) is connected with the outlet water pipe (L). The first hot water outlet pipe (K1) of the first heat exchanger (D1) is connected with a heating west area, the fourth hot water outlet pipe (K4) of the fourth heat exchanger (D4) is connected with a heating east area, the second hot water outlet pipe (K2) of the second heat exchanger (D2) and the third hot water outlet pipe (K3) of the third heat exchanger (D3) are connected with a washing hot water bucket a (G1) and a washing hot water bucket b (H1) respectively, and the fifth hot water outlet pipe (K5) of the fifth heat exchanger (D5) and the sixth hot water outlet pipe (K6) of the sixth heat exchanger (D6) are connected with a washing hot water bucket a (G2) and a washing hot water bucket b (H2) respectively.

2. The system for recycling waste heat from gas powder production of titanium dioxide according to claim 1, characterized in that: The first inlet water pipe (S1) at the upper part of the first heat exchanger (D1) and the fourth inlet water pipe (S4) at the upper part of the fourth heat exchanger (D4) are connected with a production system water supply pipe; the second inlet water pipe (S2) at the upper part of the second heat exchanger (D2), the third inlet water pipe (S3) at the upper part of the third heat exchanger (D3), the fifth inlet water pipe (S5) at the upper part of the fifth heat exchanger (D5) and the sixth inlet water pipe (S6) at the upper part of the sixth heat exchanger (D6) are connected with cooling water pipes of corresponding cold slag machines.

3. The system for recycling waste heat from gas powder production of titanium dioxide according to claim 1, characterized in that: The gas powder heat exchanger (A) has four parallelly arranged first gas powder heat exchangers (A1), second gas powder heat exchangers (A2), third gas powder heat exchangers (A3) and fourth gas powder heat exchangers (A4).

4. The system for recycling waste heat from gas powder production of titanium dioxide according to claim 1, characterized in that: The condensate water outlet pipes of the gas powder heat exchangers (A) are connected with the central washing tank.

5. The system for recycling waste heat from gas powder production of titanium dioxide according to claim 1, characterized in that: A thermometer and a liquid level meter are arranged on the side washing tank (B), the liquid level meter is interlocked with the hot water pump (C) and is automatically controlled by a DCS system.

6. The system for recycling waste heat from gas powder production of titanium dioxide according to claim 1, characterized in that: Water temperature meters (T1) are arranged on the first hot water outlet pipe (K1), the second hot water outlet pipe (K2), the third hot water outlet pipe (K3), the fourth hot water outlet pipe (K4), the fifth hot water outlet pipe (K5) and the sixth hot water outlet pipe (K6).

7. The system for recycling waste heat from gas powder production of titanium dioxide according to claim 1, characterized in that: Control valves and inlet water temperature meters (T2) are arranged on the corresponding hot water branch pipes of the second heat exchanger (D2), the third heat exchanger (D3), the fifth heat exchanger (D5) and the sixth heat exchanger (D6), and the four control valves and the four water temperature meters (T1) on the hot water outlet pipes of the four heat exchangers are respectively interlocked and controlled.

8. The system for recycling waste heat from gas powder production of titanium dioxide according to claim 1, characterized in that: The water outlet pipe (L) is connected with a drainage pipe (L3), and water directly enters the side washing water tank (B) when the gas-powder heat exchanger (A) is cleaned and the return water main (R) is drained.

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