[0031] Example 1
[0032] As an embodiment of the present invention, an ammonia supply system for preparing soda ash, such as figure 1 Shown, including heat exchange unit, distillation unit, ammonium chloride preparation unit and calcium hydroxide preparation unit;
[0033] The ammonium chloride preparation unit includes an ammonium chloride dissolving tank 4, a cyclone separator 6, and a tail gas scrubber 3. The ammonium chloride dissolving tank 4 is provided with a liquid inlet 402, a liquid outlet 403 and a solid feed inlet 401, and a tail gas scrubber The upper part of 3 is provided with a washing water inlet 301, the lower part of the tail gas scrubber 3 is provided with a washing liquid outlet 302 and an ashing tail gas inlet, and the cyclone separator 6 is provided with a feed inlet 601 of the cyclone separator and a liquid outlet 602 of the cyclone separator , The scrubbing liquid outlet 302 of the tail gas scrubber is in pipeline communication with the feed port 601 of the cyclone separator, and the liquid outlet 602 of the cyclone separator is in pipeline communication with the liquid inlet 402 of the ammonium chloride dissolution tank;
[0034] The distillation unit includes a distillation tower 2, a flasher, and a reaction barrel 10. The distillation tower is provided with a gas cap layer 203 that separates the distillation tower into a heating layer 202 located above the gas cap layer and a distillation layer located below the gas cap layer. Layer 201, the lower part of the distillation layer 201 is provided with the waste liquid outlet 207 of the distillation column, the steam inlet 208 of the distillation column, and the flash steam inlet 206 of the distillation column. The upper part of the distillation layer 201 is provided with the reaction liquid inlet 2010 of the distillation column. The waste liquid outlet 207 of the tower is connected with the liquid inlet pipeline of the flasher, the steam inlet 208 of the distillation column is used to input distillation steam, and the flash steam inlet 206 of the distillation column is connected with the steam outlet 702 of the flasher for heating. The layer 202 is provided with the ammonium chloride solution inlet 205 of the distillation tower, the ammonia gas output pipeline 204 and the ammonium chloride solution outlet 209, the ammonium chloride solution inlet 205 of the distillation tower and the liquid outlet 403 pipeline of the ammonium chloride dissolving tank The top of the reaction barrel 10 is provided with an ammonia outlet 1001, the ammonia outlet 1001 of the reaction barrel is connected with the heating layer 202 pipeline, the bottom of the reaction barrel 10 is provided with a reaction liquid outlet 1002, the reaction liquid outlet 1002 of the reaction barrel is connected to the distillation The reaction liquid inlet 2010 of the tower is connected with the pipeline, the reaction barrel 10 is provided with an ammonium chloride solution inlet 1004 and a calcium hydroxide inlet 1003, and the ammonium chloride solution inlet 1004 of the reaction barrel is connected with the ammonium chloride solution outlet 209 of the distillation tower. ;
[0035] The heat exchange unit includes a heat exchanger 1. The heat exchanger 1 has a refrigerant inlet 102, a heat medium inlet 101, a refrigerant outlet 103 and a heat medium outlet 104. The ammonia supply system for preparing soda ash is used in conjunction with the soda ash preparation unit, and the soda ash preparation unit is provided with In the calcination process, the heat medium inlet 101 of the heat exchanger is connected with the steam condensate drain pipe 805 of the calcination process of the soda ash unit, and the refrigerant outlet 103 of the heat exchanger is connected with the scrubbing water inlet 301 of the tail gas scrubber.
[0036] The calcium hydroxide preparation unit includes an ashing machine 5, which is provided with a liquid inlet 501, the liquid inlet 501 of the ashing machine is connected with the liquid outlet 602 of the cyclone separator, and the ashing machine is provided with a calcium hydroxide outlet 502, the calcium hydroxide outlet 502 of the ash disintegrator is connected to the calcium hydroxide inlet 1003 of the reaction barrel by pipeline, the top of the ash disintegrator 5 is provided with an ash discharging tail gas outlet 503, and the ash discharging tail gas outlet 503 of the ash dissolving machine is connected to the scrubber 3 The ash exhaust gas inlet pipeline is connected.
[0037] Further, the ammonia output pipeline of the distillation tower is arranged at the top of the heating layer, and the ammonium chloride solution outlet of the distillation tower is arranged at the bottom of the heating layer.
[0038] In order to further improve the evaporation efficiency, the flasher includes a first flasher 7 and a second flasher 8. The first flasher is provided with a steam outlet 702, a condensed water inlet 701, and a condensed water outlet 703. The waste liquid of the distillation column The outlet 207 is in pipeline communication with the condensate inlet 701 of the first flasher, the condensate outlet 703 of the first flasher is connected with a waste liquid bucket 704, and the second flasher is provided with a steam outlet 804, a condensate outlet 802 and The condensed water inlet 803, the flash steam inlet 206 of the distillation column and the steam outlet 702 of the first flasher are pipeline connected, and the steam outlet 804 of the second flasher 8 is pipelined with the flash steam inlet 206 of the distillation tower, The condensed water outlet 802 of the second flasher is in pipeline communication with the heat medium inlet 101 of the heat exchanger.
[0039] Further, a flash pump 801 is connected to the pipeline between the condensate outlet 802 of the second flash generator and the heat medium inlet 101 of the heat exchanger.
[0040] In order to realize the recycling of ammonium chloride generated in the process of preparing soda ash, the ammonium chloride solution inlet 205 of the distillation tower is connected with the ammonium chloride discharge pipe of the soda ash preparation unit.
[0041] In order to make full use of the high-quality heat energy of the distilled condensate, the heat exchange unit further includes a desalinated water tank 11, which is provided with a liquid inlet, and the heat medium outlet 104 of the heat exchanger is connected with the liquid inlet pipe of the desalinated tank.
[0042] In order to control the steady flow of ammonium chloride solution into the distillation tower, the pipeline between the ammonium chloride solution inlet 205 of the distillation tower of the distillation tower and the liquid outlet 403 of the ammonium chloride dissolution tank is connected with a buffer tank 404 and Ammonium chloride infusion pump 405.
[0043] Further, the ammonia supply system for preparing soda ash also includes a purification unit 9. The solid outlet 603 of the cyclone is connected with the purification unit 9 through pipelines, the ammonia outlet 204 of the distillation tower conveys ammonia to the soda ash preparation unit, and the heat exchanger is liquid. Liquid plate heat exchanger. The tail gas scrubber 3 can purify the dust generated in the process of preparing calcium hydroxide, and prevent the dust from being discharged into the atmosphere.
[0044] The ammonia supply system for preparing soda ash in this embodiment can be used to provide ammonia in the ammonia-based soda process, avoiding the use of liquid ammonia storage tanks to provide ammonia in the ammonia-based alkali manufacturing process, avoiding accidents in the liquid ammonia storage tank, and eliminating The major hazard source in the ammonia production process reduces the cost of labor; the above ammonia supply system for preparing soda ash uses the condensed water produced after the distillation tower flashes to use the waste heat after heat exchange, avoiding the high quality and low use of condensed water. The problem of direct emptying is that part of the heat in the condensed water is transferred to the cold medium water through the heat exchanger, and the ash tail gas is washed by the cold medium water to prepare the ammonium chloride solution, which reduces the energy consumption in the distillation process. ; The cold medium water is weakly alkaline after washing the ash tail gas. It can generate reaction heat when used to dissolve the ammonium chloride solution and increase the temperature of the ammonium chloride solution. After the ammonium chloride solution is sent to the distillation tower, the steam consumption can be reduced. .
[0045] An ammonia supply method for preparing soda ash, which uses the ammonia supply system for preparing soda ash as described in Example 1;
[0046] The ammonia supply method for preparing soda ash includes the following steps:
[0047] (1) Prepare the ammonium chloride solution in the ammonium chloride dissolving tank, the calcium hydroxide preparation unit prepares calcium hydroxide, and the ammonium chloride solution is sent to the heating layer of the distillation tower after the free ammonia in the ammonium chloride solution is evaporated, Ammonium chloride solution enters the reaction tank, while calcium hydroxide enters the reaction tank and mixed with ammonium chloride solution. After the reaction liquid enters the distillation layer of the distillation tower for distillation, the ammonia produced by the distillation tower is output from the ammonia outlet of the distillation tower for preparation Ammonia supply for soda ash;
[0048] (2) The steam condensed water in the calcination process of the soda ash unit enters the heat medium inlet of the heat exchanger while the water as the refrigerant enters the refrigerant inlet of the heat exchanger for heat exchange;
[0049] (3) In the heat exchange process of the heat exchanger, the water flowing out from the outlet of the refrigerant is fed into the tail gas scrubber and then flows out from the scrubber outlet of the tail gas scrubber into the cyclone separator;
[0050] (4) The washing liquid enters the ammonium chloride dissolution tank from the liquid outlet of the cyclone separator after being separated by the cyclone separator.
[0051] Further, in the step (1), when the mass fraction of the ammonium chloride solution in the ammonium chloride dissolving tank reaches 25%, the ammonium chloride solution is delivered to the free ammonia in the ammonium chloride solution of the distillation tower pair evaporation.
[0052] Further, in the step (2), the temperature of the condensed water generated by the flasher is 90-96°C, the temperature of the water as the refrigerant is 25-30°C, and the temperature of the condensed water at the heat medium outlet is 35-40 ℃, the temperature of the water at the refrigerant outlet is 48-52℃.
