Waste heat co-production citric acid monohydrate production system
By using the low-temperature exhaust gas after drying the fermentation filter residue to the heat source of the citric acid monohydrate evaporation system, the problems of high energy consumption and resource waste in the production process are solved, and the energy utilization rate and operating costs are improved.
Patent Information
- Application Number
- CN202420473502.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-12
- Publication Date
- 2025-02-21
- Estimated Expiration
- 2034-03-12
AI Technical Summary
The energy consumption is high during the production process of citric acid monohydrate, especially in the evaporation stage, and the filter slag and hot exhaust generated after fermentation cannot be effectively utilized, resulting in waste of resources and high operating costs.
By using the low-temperature exhaust gas after drying of fermentation filter residue as the heat source of the citric acid monohydrate evaporation system, a waste heat coproduction production system is designed to improve energy utilization and reduce energy consumption.
Effectively utilize waste heat, significantly reduce the energy consumption and operating costs of citric acid production in the production of monohydrate, improve energy utilization, and have broad prospects for promotion and application.
Smart Images
Figure CN222514295U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to citric acid production and fermentation industry, in particular to a waste heat co-generation citric acid monohydrate production system. Background Art
[0002] Citric acid monohydrate is a typical organic acid, which is obtained through corn fermentation, crude extraction, and refined extraction. It can be widely used in food, medicine, chemical industry and other industries. The energy consumption of citric acid monohydrate production process is very high, especially in the evaporation stage. In the production process, a certain amount of low-temperature secondary steam will be generated in the flash stage, acidification stage, drying stage, etc. After the early fermentation of citric acid monohydrate, filtration is required. The filter residue produced by filtration accounts for about 30% of the fermentation and contains about 50% water. The dry material obtained by drying the filter residue contains rich organic matter, protein, etc., which is a good feed; and the hot tail gas generated by drying is directly discharged by many manufacturers, causing waste. Since citric acid monohydrate obtains a 45% solution after crude extraction, it is necessary to increase its concentration to 81% through an evaporation concentration process and then cool and crystallize to obtain citric acid monohydrate. The evaporation concentration process requires a large amount of steam. The utility model uses the tail gas from the drying of the filter residue as a heat source for the evaporation of citric acid monohydrate, which solves the problem of waste heat on the one hand and greatly saves the operating cost of citric acid monohydrate on the other hand. The energy-saving effect is remarkable and the prospect of promotion and application is broad. Utility Model Content
[0003] The utility model provides a waste heat co-generation citric acid monohydrate production system, which uses fermentation residue drying tail gas as a heat source to evaporate citric acid monohydrate, and comprehensively utilizes the waste heat of the system to improve energy utilization and reduce energy consumption under the premise of meeting process production requirements.
[0004] The technical solution adopted in this utility model is as follows:
[0005] A waste heat co-generation citric acid monohydrate production system includes an evaporation system, which mainly includes a low-temperature tail gas conveying system, a feed preheating system, a first-stage evaporation system, a second-stage evaporation system, and a condensation system; the low-temperature tail gas conveying system mainly includes a first-stage induced draft fan, the outlet of the first-stage induced draft fan is connected to a scrubbing tower, and the dry tail gas output port on the scrubbing tower is connected to the dry tail gas inlet of a first-stage first-effect evaporator in the first-stage evaporation system; the material passes through a first-stage preheater and a second-stage preheater in sequence and enters the first-stage first-effect evaporator; the material outlet of the first-stage first-effect evaporator is connected in sequence to a first-stage first-effect separator, a first-stage first-effect feed pump, a first-stage second-effect evaporator, a first-stage second-effect separator, a first-stage second-effect feed pump, a second-stage evaporator, a second-stage separator, a discharge pump, and a concentrated liquid outlet; the secondary steam outlets of the first-stage second-effect separator and the second-stage separator are connected in sequence to a condenser of the condensation system and a condensate mixed outlet of the condenser.
[0006] The condensate outlet of the first-stage first-effect evaporator is connected to a first-stage separation tank, which is connected to the second-stage preheater and the second-stage condensate outlet of the feed preheating system through a first-stage first-effect condensate pump; the secondary steam outlet of the first-stage separation tank is connected to the hot side inlet of the second-stage evaporator. The secondary steam outlet of the first-stage first-effect separator is connected to the hot side inlet of the first-stage second-effect evaporator.
[0007] The condensate outlet of the first-stage two-effect evaporator is connected to a first-stage preheater and a first-stage condensate outlet of the feed preheating system through a first-stage two-effect condensate pump.
[0008] The condensate outlet of the second-stage evaporator is connected to the second-stage separation tank, the second-stage condensate pump, the first-stage preheater of the feed preheating system, and the first-stage condensate outlet in sequence; the tail gas outlet of the second-stage separation tank is connected to the secondary induced draft fan and the dry tail gas outlet.
[0009] The scrubbing tower is provided with a circulating cleaning pump, a cleaning regulating valve, a concentration discharge regulating valve, a cleaning liquid replenishing regulating valve, a liquid level meter, a conductivity meter, a temperature transmitter and a pressure transmitter.
[0010] The first-stage single-effect evaporator and the second-stage evaporator are both low-pressure-drop evaporators.
[0011] The evaporator, preheater and condenser used in the system are tubular or plate heat exchangers.
[0012] The flow of materials in the evaporator can be co-current, counter-current or mixed flow.
[0013] The utility model fully understands the waste heat and the evaporation characteristics of citric acid monohydrate, utilizes the dry tail gas of fermentation residue to co-produce the evaporated citric acid monohydrate, comprehensively utilizes the waste heat of the system to improve the energy utilization rate under the premise of meeting the process production, greatly saves the consumption of fresh steam, reduces energy consumption, and greatly reduces the operating cost.
[0014] The utility model can also be used for the production of anhydrous citric acid, and even the production of other organic acids such as lactic acid and oxalic acid, and can also be promoted and applied to industries such as fermentation of sugar alcohols. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a production process flowchart of the utility model;
[0016] Figure 2 This is a structural block diagram of the evaporation system of the utility model;
[0017] Figure 3 This is a structural block diagram of the gas washing system of the utility model;
[0018] Figure 2In: E101, first stage preheater; E102, second stage preheater; ES201, first stage, first effect evaporator; V201, first stage, first effect separator; ES202, first stage, second effect evaporator; V202, first stage, second effect separator; ES211, second stage evaporator; V211, second stage separator; EC301 condenser; V203, first stage separation tank; P201, first stage, first effect feed pump; P202, first stage, first effect condensate pump; V212, second stage separation tank; P211, first stage, second effect feed pump; P212, first stage, second effect condensate pump; P221, discharge pump; P222, second stage condensate pump; C002, second stage induced draft fan;
[0019] 1011 material inlet; 2012 dry tail gas inlet; 1012 first stage condensed water outlet; 1022 second stage condensed water outlet; 2031 concentrated liquid outlet; 3011 cooling water inlet; 3012 cooling water outlet; 3013 condenser condensed water mixed outlet; 4011 dry tail gas input port;
[0020] Figure 3 Middle: V401 scrubber; P401 clean liquid circulation pump; LV01, cooling water regulating valve; LV02, cleaning liquid discharge regulating valve; LV03, water replenishment regulating valve; TT01 secondary steam thermometer; PT01 secondary steam pressure gauge; LT01 liquid level gauge; DT01 conductivity meter; C001 first-stage induced draft fan; 4011 dry tail gas inlet; 4012 cleaning liquid outlet; 4013 dry tail gas outlet; 4014 cleaning liquid inlet. DETAILED DESCRIPTION
[0021] The utility model is further described in detail below in conjunction with the accompanying drawings.
[0022] The production system of citric acid monohydrate includes raw material preparation, cooking, flash evaporation, fermentation, filtration, crude extraction, acidification, ion exchange, evaporation, cooling crystallization, drying, packaging and other systems. After the fermentation process, filtration is required to separate the fermentation liquid and the filter residue. The separated filter residue contains about 50% water and needs to be dried to obtain feed. During the drying process, low-temperature tail gas of 90°C will be generated. The low-temperature tail gas can be used as a heat source for the citric acid monohydrate evaporation system to reduce system energy consumption and improve efficiency. Note: The citric acid solution crystallizes below 36.6°C to obtain citric acid monohydrate with one crystal water, and crystallizes above 36.6°C to obtain anhydrous citric acid. The cooling crystallization process is usually used to produce citric acid monohydrate.
[0023] Reference Figure 2A waste heat cogeneration citric acid monohydrate production system includes an evaporation system, which mainly includes a low-temperature tail gas delivery system, a feed preheating system, a first-stage evaporation system, a second-stage evaporation system, and a condensation system; the low-temperature tail gas delivery system mainly includes a primary induced draft fan C001, the outlet of the primary induced draft fan C001 is connected to a scrubber V401, a dry tail gas output port 4013 on the scrubber V401 and a dry tail gas inlet 2012 of a first-stage first-effect evaporator ES201 in the first-stage evaporation system The material passes through the first-stage preheater E101 and the second-stage preheater E102 of the feed preheating system in turn and then enters the first-stage first-effect evaporator ES201; the material outlet of the first-stage first-effect evaporator (ES201) is connected in turn to the first-stage first-effect separator V201, the first-stage first-effect feed pump P201, the first-stage second-effect evaporator ES202, the first-stage second-effect separator V202, the first-stage second-effect feed pump P211, the second-stage evaporator ES211, the second-stage separator V211, the discharge pump P221, and the concentrated liquid outlet 2031; the secondary steam outlets of the first-stage second-effect separator V202 and the second-stage separator V211 are connected in turn to the condenser EC301 of the condensation system and the condenser condensate mixed outlet 3013.
[0024] The condensate outlet of the first-stage single-effect evaporator ES201 is connected to a first-stage separation tank V203, which is connected to the second-stage preheater E102 and the second-stage condensate outlet 1022 of the feed preheating system through a first-stage single-effect condensate pump P202; the secondary steam outlet of the first-stage separation tank V203 is connected to the hot side inlet of the second-stage evaporator ES211.
[0025] The secondary steam outlet of the first stage single effect separator V201 is connected to the hot side inlet of the first stage double effect evaporator ES202, so that the secondary steam separated by the first stage single effect separator V201 can be used as the heat source of the first stage double effect evaporator ES202, making full use of energy.
[0026] The condensate outlet of the first stage two-effect evaporator ES202 is connected to the first stage preheater E101 of the feed preheating system and the first stage condensate outlet 1012 through the first stage two-effect condensate pump P212. That is, the heat source of the first stage preheater E101 uses the condensate of the first stage two-effect evaporator ES202, and the condensate is discharged from the system after heat exchange with the temperature reduced to about 55°C.
[0027] The condensate outlet of the second stage evaporator ES211 is connected to the second stage separation tank V212, the second stage condensate pump P222, the first stage preheater E101 of the feed preheating system, and the first stage condensate outlet 1012 in sequence; the tail gas outlet of the second stage separation tank V212 is connected to the secondary induced draft fan C002 and the dry tail gas outlet 4011. That is, the heat source of the first stage preheater E101 can also be the condensate of the second stage evaporator ES211, and the condensate is discharged from the system after the temperature is reduced to about 55°C through heat exchange.
[0028] The heat source of the second-stage preheater E102 is the condensed water from the first-stage single-effect evaporator ES201. After passing through the heat exchanger, the temperature of the condensed water is reduced to 75°C and discharged from the system.
[0029] Reference Figure 3 The scrubber V401 is provided with a circulating cleaning pump P401, a cleaning regulating valve LV01, a concentrated discharge regulating valve LV02, a cleaning liquid replenishing regulating valve LV03, a liquid level meter LT01, a conductivity meter DT01, a temperature transmitter TT01, and a pressure transmitter PT01. The conductivity meter monitors the quality of the cleaning liquid (controlled to within 150us / cm), and when the conductivity exceeds 150us / cm, LV02 is adjusted to discharge the cleaning liquid; the liquid level meter controls the opening of the water replenishment regulating valve (LV03) to ensure sufficient and stable system cleaning; the temperature transmitter TT01 and the pressure transmitter PT01 are used to monitor the operating status of the scrubber.
[0030] The first stage single effect evaporator ES201 and the second stage evaporator ES211 both use low pressure drop evaporators. The hot side pressure drop needs to be controlled within 2kpa.
[0031] The evaporator, preheater and condenser used in the system are tubular or plate heat exchangers.
[0032] The flow of materials in the evaporator can be co-current, counter-current or mixed flow.
[0033] The utility model takes the temperature of the dry low-temperature tail gas as the design basis, and the subsequent first-stage evaporator can adopt double effect or triple effect. The subsequent second-stage evaporator can adopt single effect or double effect. The subsequent condenser is a total condensation system or a separate condensation system.
[0034] The working process of the utility model is:
[0035] Reference Figure 1The low-temperature tail gas at the outlet of the tubular dryer is about 90℃ (water content 55-60%), the pressure is normal pressure, and the characteristic is saturated wet air. Since the tail gas is a mixture of steam and water, there is no stable condensation point. The low-temperature tail gas is pressurized by 3-5kpa through the first-stage induced draft fan C001 and then enters the scrubber V401. After purification, it enters the first-stage first-effect evaporator ES201 and the temperature is reduced from 90℃ to 75℃. After entering the first-stage separation tank V203, the condensed water is separated and then enters the second-stage evaporator ES211 for heat exchange. In the second-stage evaporator ES211, the temperature is reduced from 75℃ to 55℃ and then enters the second-stage separation tank V212. In the second-stage separation tank V212, the tail gas after the condensed water is separated is discharged from the system through the second-stage induced draft fan C002, and the second-stage induced draft fan is pressurized by 3-5kap. The condensed water separated by the two-stage steam-water separation tank is used as the feed preheating of the ion exchange liquid. The secondary steam from the first-stage two-effect evaporator heat exchange enters the condenser EC301 for condensation, and at the same time, the secondary steam from the second-stage evaporator also enters the condenser EC301 for condensation.
[0036] The inlet temperature of the evaporation process is 20℃, and the feed concentration is about 46%. After being preheated by the first preheater E101 and the second preheater E102, it enters the first stage first effect evaporator ES201 (evaporation temperature 70℃), then enters the first stage second effect evaporator ES202 (evaporation temperature 48℃), and then enters the second stage evaporator ES211 (evaporation temperature 48℃) after the concentration is increased to 81% and output system. The evaporated material enters the subsequent cooling crystallization system for crystallization treatment. The feed ionized liquid passes through the feed pump P101 and enters the preheater E101 and the secondary preheater E102. The preheated ionized liquid enters the first-stage first-effect evaporator ES201, and then enters the first-stage first-effect separator V201 for gas-liquid separation. The separated material enters the first-stage second-effect evaporator ES202; the material is heated and evaporated in the first-stage second-effect evaporator ES202 and enters the first-stage second-effect separator V202 for gas-liquid separation. The separated material enters the second-stage evaporator ES211, and the secondary steam after separation enters the condenser EC301 for feed condensation; the material is heated and evaporated in the second-stage evaporator ES211 and enters the second-stage separator V211 for gas-liquid separation; the separated material is transported out of the system by the discharge pump P221, and the separated secondary steam enters the condenser EC301 for condensation and then discharged from the system.
[0037] The condensed water from the first stage two-effect evaporator ES202 and the condensed water from the second stage evaporator ES211 are respectively pumped out by the first stage two-effect condensed water pump P212 and the second stage condensed water pump P222 and used as the heat source of the first stage preheater E101. The condensed water from the first stage one-effect evaporator ES201 is pumped out by the first stage one-effect condensed water pump P202 and used as the heat source of the second stage preheater E102.
[0038] In order to ensure low pressure drop on the flash steam side, a low pressure drop plate evaporator is used, and the pressure is controlled to within 2 kPa, while meeting the requirements of evaporation heat transfer.
[0039] In order to ensure the evaporation temperature of each effect, a low pressure drop condenser is used. At the same time, the circulation inlet temperature is required not to exceed 30°C and to be sufficient.
Claims
1. A waste heat cogeneration citric acid monohydrate production system, comprising an evaporation system, characterized in that: The invention mainly comprises a low-temperature tail gas conveying system, a feed preheating system, a first-stage evaporation system, a second-stage evaporation system, and a condensation system; the low-temperature tail gas conveying system mainly comprises a first-stage induced draft fan (C001), the outlet of the first-stage induced draft fan (C001) is connected to a scrubber (V401), a dry tail gas outlet (4013) on the scrubber (V401) and a dry tail gas inlet (2012) of a first-stage first-effect evaporator (ES201) in the first-stage evaporation system. ) are connected; the material passes through the first preheater (E101) and the second preheater (E102) in sequence and then enters the first first-effect evaporator (ES201); the material outlet of the first first-effect evaporator (ES201) is connected in sequence to the first first-effect separator (V201), the first first-effect feed pump (P201), the first second-effect evaporator (ES202), the first second-effect separator (V202), the first second-effect feed pump (P211), the second evaporator (ES211), the second separator (V211), the discharge pump (P221), and the concentrated liquid outlet (2031); the secondary steam outlets of the first second-effect separator (V202) and the second separator (V211) are connected in sequence to the condenser (EC301) of the condensation system and the condensate mixed outlet (3013) of the condenser.
2. The waste heat cogeneration citric acid monohydrate production system according to claim 1, characterized in that: The condensate outlet of the first-stage single-effect evaporator (ES201) is connected to a first-stage separation tank (V203), and the first-stage separation tank (V203) is connected to the second-stage preheater (E102) and the second-stage condensate outlet (1022) of the feed preheating system through a first-stage single-effect condensate pump (P202); the secondary steam outlet of the first-stage separation tank (V203) is connected to the hot side inlet of the second-stage evaporator (ES211).
3. The waste heat cogeneration citric acid monohydrate production system according to claim 1, characterized in that: The secondary steam outlet of the first-stage first-effect separator (V201) is connected to the hot side inlet of the first-stage second-effect evaporator (ES202).
4. The waste heat cogeneration citric acid monohydrate production system according to claim 1, characterized in that: Said The condensate outlet of the first-stage two-effect evaporator (ES202) is connected to a first-stage preheater (E101) and a first-stage condensate outlet (1012) of the feed preheating system through a first-stage two-effect condensate pump (P212).
5. The waste heat cogeneration citric acid monohydrate production system according to claim 1, characterized in that: The condensate outlet of the second-stage evaporator (ES211) is connected in sequence to the second-stage separation tank (V212), the second-stage condensate pump (P222), the first-stage preheater (E101) of the feed preheating system, and the first-stage condensate outlet (1012); the exhaust gas outlet of the second-stage separation tank (V212) is connected to the secondary induced draft fan (C002) and the dry exhaust gas outlet (4011).
6. The waste heat cogeneration citric acid monohydrate production system according to claim 1, characterized in that: The scrubbing tower (V401) is provided with a circulating cleaning pump (P401), a cleaning regulating valve (LV01), a concentration discharge regulating valve (LV02), a cleaning liquid replenishing regulating valve (LV03), a liquid level meter (LT01), a conductivity meter (DT01), a temperature transmitter (TT01), and a pressure transmitter (PT01).
7. The waste heat cogeneration citric acid monohydrate production system according to claim 1, characterized in that: The first-stage single-effect evaporator (ES201) and the second-stage evaporator (ES211) both use low-pressure-drop evaporators.
8. The waste heat cogeneration citric acid monohydrate production system according to claim 1, characterized in that: The evaporator, preheater and condenser used in the system are tubular or plate heat exchangers.
9. The waste heat cogeneration citric acid monohydrate production system according to claim 1, characterized in that: The flow of materials in the evaporator can be co-current, counter-current or mixed flow.